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Cited by 1,516Photorefractive and Nonlinear OpticsPhotonic and Optical DevicesAcoustic Wave Resonator Technologies

Integrated photonics on thin-film lithium niobate

Open access
Zhu, Di, Shao, Linbo, Yu, Mengjie, Cheng, Rebecca, Desiatov, Boris, Xin, C. J., Hu, Yaowen, Holzgrafe, Jeffrey +7 more·2021·Advances in Optics and Photonics
DOI 10.1364/aop.411024
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Abstract

Lithium niobate (LN), an outstanding and versatile material, has influenced our daily life for decades—from enabling high-speed optical communications that form the backbone of the Internet to realizing radio-frequency filtering used in our cell phones. This half-century-old material is currently embracing a revolution in thin-film LN integrated photonics. The successes of manufacturing wafer-scale, high-quality thin films of LN-on-insulator (LNOI) and breakthroughs in nanofabrication techniques have made high-performance integrated nanophotonic components possible. With rapid development in the past few years, some of these thin-film LN devices, such as optical modulators and nonlinear wavelength converters, have already outperformed their legacy counterparts realized in bulk LN crystals. Furthermore, the nanophotonic integration has enabled ultra-low-loss resonators in LN, which has unlocked many novel applications such as optical frequency combs and quantum transducers. In this review, we cover—from basic principles to the state of the art—the diverse aspects of integrated thin-film LN photonics, including the materials, basic passive components, and various active devices based on electro-optics, all-optical nonlinearities, and acousto-optics. We also identify challenges that this platform is currently facing and point out future opportunities. The field of integrated LNOI photonics is advancing rapidly and poised to make critical impacts on a broad range of applications in communication, signal processing, and quantum information.

AI snapshot

Written from the paper’s full text.

TL;DR

This review surveys integrated photonics on thin-film lithium niobate (LNOI), covering material properties, passive components, electro-optic, nonlinear, and piezo-optomechanical devices, and heterogeneous integration. It argues that LNOI has enabled record-performance modulators, nonlinear converters, and comb sources, while identifying challenges such as photorefraction, charge-carrier effects, and wafer-scale foundry compatibility.

Key findings

  • LNOI waveguides and resonators have improved dramatically: propagation loss fell from >6 dB/cm in 2007 to 0.027 dB/cm in 2017, intrinsic Q-factors reach ~10^7, and fiber-to-chip coupling as low as 0.54/0.59 dB per facet for TE/TM has been shown with a SiON cladding waveguide.
  • Electro-optic modulators on LNOI achieve VπL of 2.1–2.5 V-cm in monolithic MZMs, >100 GHz bandwidth at CMOS-compatible voltages, and coherent data rates up to 320 Gbit/s; hybrid LN/SOI modulators exceed 100 GHz 3-dB EO bandwidth.
  • Nonlinear devices include PPLN ridge SHG with 4600%/W·cm² normalized efficiency in a 300 μm waveguide, PPLN microring SHG at 5,000%/mW, SPDC with coincidence-to-accidental ratio 668 ± 7 at 12 MHz in a 5 mm PPLN waveguide, Kerr combs spanning 700 nm, soliton microcombs >200 nm at 1.5 μm and >300 nm at 2 μm, and supercontinuum spanning 0.35–4.1 µm with 240 pJ pulse energy.
  • Piezo-optomechanics and quantum transduction show microwave-to-optical conversion efficiency of 2×10^-5, later 1% on-chip, and piezo-optomechanical single-microwave-photon-to-optical-photon conversion efficiency of 5%; integrated acousto-optic frequency shifters are 10–100× more efficient than earlier AlN devices but still only a few percent efficient.

Methods

  • This is a review article, not a primary experimental study; it synthesizes material properties, passive optics, electro-optics, all-optical nonlinearity, piezo-optomechanics, heterogeneous integration, and challenges/opportunities.
  • The main analysis is a qualitative and quantitative synthesis of reported literature, organized with comparison tables for material properties, cavity Q-factors, EO modulators, and SHG performance.

Limitations

  • The paper states key challenges: charge-carrier effects (photorefraction, photoconductivity, dielectric relaxation) cause bias/detuning drift in LNOI and are stronger than in bulk; strong Raman gain competes with Kerr comb/soliton formation; fiber-to-chip coupling and packaging remain difficult; LN is not CMOS-compatible due to lithium contamination; and wafer-scale foundry access is limited.
  • Evident from the text: as a review, it does not describe a systematic search protocol or meta-analysis, and it notes that performance comparisons across literature are complicated by different lasers, detectors, amplifiers, and measurement conditions (e.g., for SFDR comparisons).

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1364/aop.411024

Cites

525 of 525 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 348 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Broadband absorption spectra measured on thin film were consistent with a reference bulk crystal.

    “Broadband absorption spectra were measured that is consistent with a reference bulk crystal.”
    Quote in the paperSubstantial claim
  • Findingown data

    The dispersion can be carefully tailored with small variations in the geometry.

    “Additionally, the dispersion can be carefully tailored with small variations in the geometry”
    Quote in the paperSubstantial claim
  • Findingown data

    Different cladding configurations (uncladded, 1 μm SiO2 top cladding, and suspended/free standing structure) affect the TE mode dispersion of TFLN waveguides.

    “The effect of different cladding configurations on the TE mode dispersion of TFLN waveguides, including uncladded, 1 μm SiO 2 top cladding, and suspended/free standing structure.”
    Quote in the paperSubstantial claim
  • Findingown data

    The TE mode GVD for thin-film LN waveguides can be geometrically controlled by varying width, etch depth, and initial film thickness.

    “We compare the TE mode GVD for thin-film LN waveguides with different widths (b), etch depths (b), and initial film thicknesses (d) against LN's intrinsic material dispersion (a).”
    • Also stated in: § 8. Conclusion · plain
      “We evaluate the effect of different geometric parameters, including waveguide width, etch depth, initial LN film thickness, and the etch angle on the dispersion curve.”
    Quote in the paperSubstantial claim
  • Findingown data

    In thin-film LN, the GVD curve takes on a larger range of β2 value than for bulk crystal.

    “it can be seen that in the case of thin-film LN, the GVD curve takes on a larger range of 𝛽𝛽 2 value than for bulk crystal.”
    Quote in the paperSubstantial claim
  • May combine two claims. 183
  • Classified as probably not a substantial claim. 123
  • The quote only partly states this claim. 2

  • May combine two claims.

    Findingown data

    Time-resolved spectral hole burning revealed hole widths and depths comparable to bulk Tm:LN under similar conditions, accounting for power broadening and spectral diffusion, and with two-orders of magnitude lower laser power than Ti-indiffused waveguides owing to small (0.07 μm2) transverse area of optical mode.

    “Time-resolved spectral hole burning revealed hole widths and depths that were comparable to that of bulk Tm:LN measured under similar conditions, accounting for power broadening and spectral diffusion, and with two-orders of magnitude lower laser power than Ti-indiffused waveguides owing to the small (0.07 μm 2 ) transverse area of the optical mode.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Resonance fluorescence revealed a fluorescence linewidth of 170 GHz, comparable to literature value of 180 GHz, with difference owing to imperfect wavelength calibration.

    “The sample was cooled to 2.8 K, and resonance fluorescence was performed revealing a fluorescence linewidth of 170 GHz, comparable to the literature value of 180 GHz, with the difference owing to imperfect wavelength calibration.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given

    From the authors' own experience, on bulk LN, pyroelectric effect tends to cause electrostatic discharge and damage nanowires under rapid temperature change, but this effect does not seem to happen on LNOI waveguides.

    “From our own experience, on bulk LN, pyroelectric effect tends to cause electrostatic discharge and damage the nanowires under rapid temperature change.But this effect does not seem to happen on LNOI waveguides.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Time-resolved excitation revealed a fluorescence lifetime of 3.2 ms, somewhat larger than 2.0 ms population lifetime of 4I13/2 level measured in bulk sample by spectral hole burning, with difference to be investigated in future work.

    “The sample was further cooled to 1.7 K, and time-resolved excitation revealed a fluorescence lifetime of 3.2 ms, which is somewhat larger than a 2.0 ms population lifetime of the 4 I 13/2 level measured in a bulk sample by spectral hole burning, with the difference to be investigated in future work.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Loaded Qs of 200,000 were measured at 1532 nm, owing to absorption of Er, with loaded Qs up to 1 million off resonant from Er3+ transition at 1515 nm (average Q 500,000).

    “Specifically, loaded Qs of 200,000 were measured at 1532 nm, owing to the absorption of Er, with loaded Qs of up to 1 million off resonant from the Er 3+ transition at 1515 nm (average Q of 500,000).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    A reduction in fluorescence lifetime of 0.6 ms (Purcell enhancement of 3) of ions in ring compared to waveguide was measured, consistent with measured Qs, optical mode volumes and field overlap with implanted ions.

    “Supporting cavity-ion coupling, they also measure a reduction in fluorescence lifetime of 0.6 ms (corresponding to a Purcell enhancement of 3) of ions in the ring compared to the waveguide, consistent with the measured Qs, optical mode volumes and field overlap with implanted ions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Nanophotonic integration enabled ultra-low-loss resonators in LN, which unlocked applications such as optical frequency combs and quantum transducers.

    “the nanophotonic integration enabled ultra-low-loss resonators in LN, which unlocked many novel applications such as optical frequency combs and quantum transducers.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The CMP process yields waveguides with sub-nanometer surface roughness and propagation losses as low as 0.027 dB/cm.

    “The CMP process yields waveguides with sub-nanometer surface roughness and propagation losses as low as 0.027 dB/cm [12].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [12] Wu, 2018, Nanomaterials (Basel) source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Hybrid approaches represent a promising path towards heterogeneous integration of LN with other PIC platforms, complementing their missing functionalities such as EO modulation, second-order nonlinearity, and quasi-phase matching.

    “These hybrid approaches represent a promising path towards heterogeneous integration of LN with other PIC platforms, complementing their missing functionalities such as EO modulation, second-order nonlinearity, and the ability of quasi-phase matching.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    LN has a third-order nonlinear coefficient (n2 = 1.8×10^-19 m2/W) that is comparable to other commonly used optical materials, making Kerr comb generation possible.

    “LN also has a third-order nonlinear coefficient (𝑛𝑛 2 = 1.8⨉10 -19 m 2 /W) that is comparable to other commonly used optical materials, making Kerr comb generation possible.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Devices with optical loss below 0.1 dB/cm can now be routinely produced by several groups, making LNOI a reliable and scalable low-loss platform for integrated photonics.

    “Devices with optical loss below 0.1 dB/cm can now be routinely produced by several groups, making LNOI a reliable and scalable low-loss platform for integrated photonics.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    LN's exceptional Pockels coefficient (r33 ≈ 31 pm/V) has made it the material of choice for electro-optic modulators, which are at the core of telecommunication networks.

    “Crucially, LN's exceptional Pockels coefficient (𝑟𝑟 33 ≈ 31pm/V) has made it the material of choice for electro-optic (EO) modulators, which is at the core of telecommunication networks.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Another class of waveguides on thin-film LN is the rib-loaded waveguide, which avoids the necessity of LN etching.

    “Another class of waveguides on thin-film LN is the rib-loaded waveguide, which avoids the necessity of LN etching.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    LN has a broad transparency window from 350 nm to 5 μm, covering the visible, near-infrared and mid-infrared wavelength range.

    “LN has a broad transparency window, from 350 nm to 5 μm, covering the visible, near-infrared and mid-infrared wavelength range.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisereasoning

    LN had generally fallen behind competing integrated photonic platforms, mainly due to significant difficulties of material integration and processing.

    “Despite its great potential, LN had generally fallen behind the competing integrated photonic platforms, mainly due to the significant difficulties of material integration and processing.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Most LNOI fabrication is performed using congruent rather than stoichiometric LN, meaning that the crystals are lithium deficient.

    “It is important to note that most LNOI fabrication is performed using congruent rather than stoichiometric LN, meaning that the crystals are lithium deficient [44].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [44]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Direct bonding is preferred over BCB bonding for many applications because the higher annealing temperatures allowed by the process are necessary for recovering nonlinear and electro-optic properties of the ion-sliced material.

    “However, while both BCB and direct bonding techniques have succeeded in producing single-crystalline LNOI, the direct bonding method is preferred for many applications, as the higher annealing temperatures allowed by the process are necessary for recovering nonlinear and electro-optic properties of the ion-sliced material [35].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Poberaj, 2012, Laser Photon. Rev. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Currently, pure physical etching with Ar+ plasma (or Ar+ milling) is among the most popular dry etching approaches for LNOI.

    “Currently, pure physical etching with Ar + plasma (or Ar + milling) [83] is among the most popular dry etching approaches for LNOI.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [83] Chen, 2009, J. Appl. Phys. source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    LN allows ferroelectric domain engineering, making it a leading material for nonlinear optical frequency conversion and generation.

    “Moreover, it allows ferroelectric domain engineering, which makes it a leading material for nonlinear optical frequency conversion and generation”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    The speed of sound on the surface of bulk LN or inside thin-film LN is ~4 km/s, resulting in a higher acoustic index than SiO2 and sapphire.

    “Considering acoustic applications, the speed of sound on the surface of bulk LN or inside thin-film LN is ~4 km/s, resulting in a higher acoustic index than SiO 2 and sapphire.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    LN is a noncentrosymmetric crystal and possesses large second-order nonlinear coefficients (d33 = -27 pm/V).

    “Unlike Si and SiN x , LN is a noncentrosymmetric crystal and possesses large second-order nonlinear coefficients (𝑑𝑑 33 = -27 pm/V).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    Lithium niobate is one of the most versatile and attractive materials for photonics owing to its exceptional electro-, nonlinear-, and acousto-optic properties, as well as its wide transparency window and relatively high refractive index.

    “Studied since the 1960s, lithium niobate (LiNbO 3 , LN) is one of the most versatile and attractive materials for photonics, owing to its exceptional electro-, nonlinear-, and acousto-optic properties, as well as its wide transparency window and relatively high refractive index.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    LN has a high Curie temperature (~1210 °C) that ensures a stable ferroelectric phase compatible with a wide range of fabrication processes and operation conditions.

    “Its high Curie temperature (~1210 o C) ensures a stable ferroelectric phase to render it compatible with a wide range of fabrication processes and operation conditions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The limitations of bulk LN devices and the desire to integrate many different functionalities on the same LN chip motivated the production of thin-film LN-on-insulator (LNOI) wafers.

    “These limitations, along with the desire to integrate many different functionalities on the same LN chip, motivated the production of thin-film LN-on-insulator (LNOI) wafers.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Currently, LNOI wafers with sizes up to 6 inches have been made commercially available from companies such as NanoLN, Partow Technologies, NGK Insulators, and SRICO.

    “Currently, LNOI wafers with sizes up to 6 inches have been made commercially available from companies such as NanoLN, Partow Technologies, NGK Insulators, and SRICO.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Low-loss waveguides with propagation losses below 1 dB/cm were made possible since 2015 using multiple methods, and a few dB/m can now be achieved using dry-etching and chemo-mechanical polishing.

    “Low-loss waveguides with propagation losses below 1 dB/cm were made possible since 2015 using multiple methods, and a few dB/m can now be achieved using dry-etching and chemo-mechanical polishing.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    The availability of thin-film LNOI facilitates the fabrication of monolithic ridge waveguides with large index contrast (roughly an order of magnitude larger than ion-diffused waveguides) and strong mode confinement.

    “The availability of thin-film LNOI facilitates the fabrication of monolithic ridge waveguides with large index contrast (roughly an order of magnitude larger than ion-diffused waveguides) and strong mode confinement.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Dry etching of LN had been notoriously difficult; unlike most other integrated photonics platforms such as Si and SiNx, a proper reactive ion-etching recipe was not available for LN.

    “However, dry etching of LN had been notoriously difficult.Unlike most other integrated photonics platforms such as Si and SiN x , a proper reactive ion-etching recipe was not available for LN.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationnone given

    Compared to mechanical dicing/polishing and wet etching, dry etching is much preferred for integrated photonics because it is anisotropic, well-controlled in etch depth, able to transfer complex 2D patterns, and compatible with multi-layer processing.

    “Compared to mechanical dicing/polishing and wet etching, dry etching is much preferred for integrated photonics.It is anisotropic, well-controlled in etch depth, able to transfer complex 2D patterns, and compatible with multi-layer processing.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Fluorine-based reactive-ion etching (RIE) can remove LN effectively by forming volatile, fluorinated niobium species, but it forms non-volatile lithium fluoride (LiF) and results in severe redeposition problems.

    “Fluorine-based reactive-ion etching (RIE) can remove LN effectively by forming volatile, fluorinated niobium (Nb) species [77].However, it forms lithium fluoride (LiF), which is non-volatile, and result in severe redeposition problems [78].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [77] Hu, 2006, J. Vac. Sci. Technol. A source

      Not checked in the free run.

    • cites [78] Nagata, 1998, J. Cryst. Growth source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    A major drawback of traditional diffused or proton-exchange waveguides is low index contrast, resulting in weak optical confinement (mode area of 10 to 100 μm2) and large bending radius (millimeter).

    “A major drawback of these waveguides is the low index contrast, resulting in weak optical confinement (mode area of 10 to 100 μm 2 ) and large bending radius (millimeter).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    EO modulators realized using traditional diffusion-based bulk LN require large drive voltages and challenging RF-optical dispersion engineering.

    “For example, EO modulators realized using this approach require large drive voltages and challenging RF-optical dispersion engineering.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    It is impossible to make tight bends in traditional diffusion-based bulk LN waveguides, which prevents realization of low-loss ring or race-track resonators.

    “Furthermore, it is impossible to make tight bends in these waveguides, which prevents realization of, for example, low-loss ring or race-track resonators.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Deposition and growth methods for LN thin films failed to produce highly crystalline materials, and lattice matching requirements severely limit substrate options for epitaxial growth.

    “However, these approaches failed to produce highly crystalline materials, and lattice matching requirements severely limit the substrate options for epitaxial growth [35].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Poberaj, 2012, Laser Photon. Rev. source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    Traditional integrated LN devices based on low-index-contrast waveguides have weak mode confinement, large device footprints, and reduced nonlinear efficiencies.

    “These devices have weak mode confinement, large device footprints, and reduced nonlinear efficiencies.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    LN has a relatively large refractive index (~2.2 at 1550 nm) that allows high-index-contrast waveguides to be formed on most amorphous and crystal substrates (e.g., SiO2 or sapphire).

    “Its relatively large refractive index (~2.2 at 1550 nm) allows high-index-contrast waveguides to be formed on top of most amorphous and crystal substrates (e.g., SiO 2 or sapphire).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    The tight optical confinement of LNOI waveguides drastically reduces device footprint and enhances nonlinear optical interactions.

    “The tight optical confinement of LNOI waveguides drastically reduces device footprint and enhances nonlinear optical interactions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Bonded LNOI has the unique advantage that it allows buried metal layers, which can serve as an efficient optical reflector to minimize downward coupling and improve coupling efficiency.

    “On the other hand, bonded LNOI has the unique advantage that it allows buried metal layers, which can serve as an efficient optical reflector to minimize downward coupling and improve coupling efficiency [129,130].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [129] Chen, 2017, Opt. Mater. source

      Not checked in the free run.

    • cites [130] Kar, 2019, Opt. Express source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    In phase modulators, an applied voltage induces an index change in the waveguide and causes a phase shift of the transmitted light.

    “In phase modulators (see Figure 10(a)), an applied voltage induces an index change in the waveguide and causes a phase shift of the transmitted light.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The push-pull MZM configuration is the most common configuration in thin-film LN modulators.

    “This is the most common configuration in thin-film LN modulators.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisenone given

    The EO effect directly mixes optical and RF fields, enabling optical modulation, sideband generation, and frequency shifting in the GHz range.

    “This effect directly mixes optical and RF fields, enabling optical modulation, sideband generation, and frequency shifting in the GHz range.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    In quantum applications, EO-based frequency conversion serves as a promising candidate to link microwave photons and optical photons.

    “In quantum applications, EO-based frequency conversion serves as a promising candidate to link microwave photons (e.g. in superconducting quantum systems) and optical photons (for long-haul networks).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Integrated EO modulators in bulk LN have been studied extensively for decades.

    “Integrated EO modulators in bulk LN have been studied extensively for decades [192][193][194].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [192] Janner, 2009, Laser Photon. Rev. source

      Not checked in the free run.

    • cites [193] Ren, 2019, IEEE Photon. Technol. Lett. source

      Not checked in the free run.

    • cites [194] Wright, 2017, Phys. Rev. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Photonic crystal cavities simultaneously possess high Q-factor and wavelength-scale mode volume, which enhance optical nonlinearities and reduce the physical footprint.

    “Photonic crystal (PhC) cavities simultaneously possess high Q-factor and wavelength-scale mode volume, which enhance optical nonlinearities and reduce the physical footprint.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    IQ modulators can encode information in both amplitude and phase, and are important for coherent transmission systems.

    “IQ modulators can encode information in both amplitude and phase, and are important for coherent transmission systems.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Z-cut EO modulators can also be implemented by placing electrodes on top of the waveguides, but so far they are less common in thin-film LN devices because it is more difficult to efficiently deliver the electric field on the sub-micrometer waveguides while maintaining low microwave and optical loss.

    “In principle, Z-cut EO modulators can also be implemented by placing electrodes on top of the waveguides.But so far they are less common in thin-film LN devices, because it is more difficult to efficiently deliver the electric field on the sub-micrometer waveguides while maintaining low microwave and optical loss.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Mechanically polished, millimeter-scale disk resonators made from pristine bulk LN crystals have shown Q-factors as high as 2×10^8, an order of magnitude higher than what has been demonstrated in thin-film LN.

    “It is worth noting that mechanically polished, millimeter-scale disk resonators made from pristine bulk LN crystals have shown Q-factors as high as 2×10 8 [93], an order of magnitude higher than what has been demonstrated in thin-film LN.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [93] Ilchenko, 2004, Phys. Rev. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    LN is anisotropic and Z is the extraordinary axis (n33 = ne = 2.14 and n11 = n22 = no = 2.21 at 1550 nm).

    “Note that LN is anisotropic and Z is the extraordinary axis ( 𝑛𝑛 33 = 𝑛𝑛 𝑒𝑒 = 2.14 and 𝑛𝑛 11 = 𝑛𝑛 22 = 𝑛𝑛 𝑜𝑜 = 2.21 at 1550 nm).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    Migrating bulk LN modulators into the thin-film platform brings unique advantages and engineering opportunities.

    “Though basic principles remain similar, migrating these modulators into the thin-film platform brings unique advantages and engineering opportunities.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Low-loss ridge waveguides with closely placed microwave electrodes, strong field confinement and high-quality resonators in thin-film LN drastically improve EO interaction strength.

    “Low-loss ridge waveguides with closely placed microwave electrodes, strong field confinement and high-quality resonators in thin-film LN drastically improve EO interaction strength.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    When driven with a strong RF signal, phase modulators generate sidebands, and can be used for frequency comb generation and frequency shifting.

    “When driven with a strong RF signal, phase modulators generate sidebands, and can be used for frequency comb generation [195] and frequency shifting [196,197].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [195] Izutsu, 1981, IEEE J. Quantum Electron. source

      Not checked in the free run.

    • cites [196] Jian, 2019, Opt. Express source

      Not checked in the free run.

    • cites [197] Xu, 2019, APL Photon. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    There have been a number of reports on LNOI grating couplers, with a current record coupling efficiency as low as -3.5 dB per coupler.

    “There have been a number of reports on LNOI grating couplers [121,129-134], with a current record coupling efficiency as low as -3.5 dB per coupler [121] (see Figure 8(b)).”
    Quote in the paperNot a substantial claim0 of 7 sources checked
    • cites [121] Jian, 2018, Opt. Express source

      Not checked in the free run.

    • cites [129] Chen, 2017, Opt. Mater. source

      Not checked in the free run.

    • cites [130] Kar, 2019, Opt. Express source

      Not checked in the free run.

    • cites [131] Nisar, 2017, IEEE Photon. J. source

      Not checked in the free run.

    • cites [132] Baghban, 2017, Opt. Express source

      Not checked in the free run.

    • cites [133] Wang, 2020, Appl. Phys. Lett. source

      Not checked in the free run.

    • cites [134] Tiecke, 2015, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In bulk LN waveguides, the off-diagonal EO coefficient has been used for single-sideband modulation and magnetic-free optical isolation by mimicking an EO-driven rotating waveplate.

    “In bulk LN waveguides, it has been used for single-sideband modulation and magnetic-free optical isolation by mimicking an EO-driven rotating waveplate [188].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [188] Fan, 2018, Sci. Adv. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Optical microcavities enable wavelength filtering and strongly enhance nonlinear-, electro-, and acousto-optic interactions.

    “They enable wavelength filtering and strongly enhance nonlinear-, electro-, and acousto-optic interactions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    A typical intensity modulator based on a Mach-Zehnder interferometer embedded in a coplanar waveguide (CPW) electrode features a push-pull configuration, where the two arms naturally experience electric fields with opposite polarities and thus opposite phase shifts.

    “Figure 10(b) shows a typical intensity modulator based on a Mach-Zehnder interferometer embedded in a coplanar waveguide (CPW) electrode.This design features a push-pull configuration, where the two arms naturally experience electric fields with opposite polarities and thus opposite phase shifts.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Premisenone given

    The electro-optic effect is perhaps the most attractive property of LN.

    “The electro-optic (EO) effect is perhaps the most attractive property of LN.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    In LN modulators, the strongest and most utilized EO coefficient is r33 (~31 pm/V), which induces an index change along the Z crystal axis when the E field is applied along z as well.

    “In LN modulators, the strongest and most utilized EO coefficient is 𝑟𝑟 33 (~31 pm/V), which induces an index change along the Z crystal axis when the E field is applied along z as well.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Another noteworthy but less exploited EO coefficient is r51 = r42 ≈ 30 pm/V; it causes deformation of the index ellipsoid in the xz or yz crystal plane when a DC/RF field is applied along x or y, respectively.

    “Another noteworthy but less exploited EO coefficient is 𝑟𝑟 51 = 𝑟𝑟 42 ≈ 30 pm/V.It causes deformation of index ellipsoid in the 𝑥𝑥𝑧𝑧 or 𝑦𝑦𝑧𝑧 crystal plane when DC/RF field is applied along 𝑥𝑥 or 𝑦𝑦 , respectively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    With small mode volume and large local field intensity, photorefractive effects are enhanced to the extreme, enabling photon-level tuning of cavity resonances.

    “With small mode volume and large local field intensity, photorefractive effects (discussed in Sec.7) are enhanced to the extreme, enabling photon-level tuning of cavity resonances [183].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [183] Boyd, 2019

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Grating couplers allow vertical coupling at arbitrary positions of the chip with relatively large alignment tolerance, but their operation bandwidth is narrow and they are sensitive to polarization.

    “Grating couplers allow vertical coupling at arbitrary positions of the chip with relatively large alignment tolerance.However, their operation bandwidth is narrow, and they are sensitive to polarization.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Combining two MZMs can realize an in-phase/quadrature (IQ) modulator.

    “In addition, combining two MZMs can realize an in-phase/quadrature (IQ) modulator (see Figure 10(c)) [16].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [16] Xu, 2020, Nat. Commun. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    LNOI resonators have enabled low-voltage EO modulators, broadband EO frequency comb generation, ultra-efficient parametric wavelength conversions, and Kerr comb generation.

    “Furthermore, resonators have enabled low-voltage EO modulators [55,85,171], broadband EO frequency comb generation [26], ultra-efficient parametric wavelength conversions [30,31,94,168,169,172,173], and Kerr comb generation [27,28,174,175].”
    Quote in the paperNot a substantial claim0 of 10 sources checked
    • cites [55] Guarino, 2007, Nat. Photonics source

      Not checked in the free run.

    • cites [85] Wang, 2018, Opt. Express source

      Not checked in the free run.

    • cites [171] Gong, 2019, Opt. Lett. source

      Not checked in the free run.

    • cites [26] Zhang, 2019, Nature source

      Not checked in the free run.

    • cites [30] Chen, 2019, Optica source

      Not checked in the free run.

    • cites [31] Lu, 2019, Optica source

      Not checked in the free run.

    • cites [94] Wolf, 2017, Opt. Express source

      Not checked in the free run.

    • cites [168] Wolf, 2018, Optica source

      Not checked in the free run.

    • cites [169] Chen, 2018, OSA Continuum source

      Not checked in the free run.

    • cites [172] Yu, 2020, Light Sci Appl source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    LN has been the material of choice for modulators because of its exceptional EO property, low optical and microwave losses, and excellent temperature stability.

    “LN has been the material of choice for modulators because of its exceptional EO property, low optical and microwave losses, and excellent temperature stability.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Besides MZM, Michelson interferometer modulator (MIM) has also been studied.

    “Besides MZM, Michelson interferometer modulator (MIM) has also been studied [198,199], as illustrated in Figure 10(d).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [198] Rao, 2018, IEEE J. Sel. Top. Quantum Electron. source

      Not checked in the free run.

    • cites [199] Honardoost, 2018, J. Lightwave Technol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Microring and racetrack resonators support cleaner resonance modes than microdisks due to the suppression of higher-order radial modes.

    “Microring and racetrack resonators are formed by waveguide loops and support cleaner resonance modes than microdisks due to the suppression of higher-order radial modes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The concept of creating a photonic two-level system was first demonstrated in 1998.

    “The concept of creating a photonic two-level system was first demonstrated in 1998 [257].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [257] Rueda, 2016, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Shorter wavelength requires lower Vπ.

    “In addition, shorter wavelength requires lower 𝑉𝑉 𝜋𝜋 .”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The phase modulator can potentially increase the spectral density with any integer division of the original comb spacing.

    “Potentially the phase-modulator can increase the spectral density with any integer division of the original comb spacing.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Frequency combs are powerful tools for precision spectroscopy.

    “Frequency combs are powerful tools for precision spectroscopy [249].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [249] Griffiths, 2007 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Dual-comb spectroscopy offers broadband measurements with resolution given by the comb line spacing and frequency accuracy provided by an atomic clock.

    “This technique holds promise in several aspects as it offers broadband measurements with a resolution given by the comb line spacing and a frequency accuracy provided by an atomic clock.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A typical few-micron-gap CPW electrode has a capacitance on the order of 100 pF/m, resulting in a RC-limited, 3-dB EO bandwidth of about 15 GHz in a 2 mm-long modulator.

    “For example, a typical few-micron-gap CPW electrode has a capacitance on the order of 100 pF/m, resulting in a RC-limited, 3-dB EO bandwidth of about 15 GHz in a 2 mm-long modulator [85].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [85] Wang, 2018, Opt. Express source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    The Vπ of a modulator depends inversely on its length L in the ideal case, and VπL is a commonly quoted figure for comparing EO interaction strength.

    “The 𝑉𝑉 𝜋𝜋 of a modulator depends inversely on its length L in the ideal case, and 𝑉𝑉 𝜋𝜋 𝐿𝐿 is a commonly quoted figure for comparing EO interaction strength.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    While optical group and phase velocities/indices differ significantly in thin-film LN waveguides (usually >15% difference), microwave transmission lines have relatively small dispersion so their group and phase velocities/indices are similar (usually <1% difference and will asymptotically approach a constant at higher frequencies).

    “It is worth noting that while the optical group and phase velocities/indices differ significantly in thin-film LN waveguides (usually >15% difference), microwave transmission lines have relatively small dispersion so their group and phase velocities/indices are similar (usually < 1% difference and will asymptotically approach a constant at higher frequencies).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In resonant EO combs, flat dispersion is desirable; otherwise, mismatch between the microwave frequency and the cavity FSR introduces a spectral cut-off to the comb spectrum.

    “In resonant EO-combs, a flat dispersion is desirable; otherwise, the mismatch between the microwave frequency and the cavity FSR introduces a spectral cut-off to the comb spectrum, which can be numerically modelled [248].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [248]

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Unlike Kerr combs, resonant EO comb generation is not sensitive to group velocity dispersion at the pump frequency, so it could potentially extend to a wider range of optical pump wavelengths.

    “As opposed to Kerr combs, this process of comb generation is not sensitive to the group velocity dispersion at the pump frequency; therefore, it could potentially extend to a wider range of optical pump wavelengths.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    EO comb sources can provide high agility, flexible operating frequency, and tunable repetition rate.

    “These EO comb sources can also provide high agility, flexible operating frequency, and tunable repetition rate.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    In a high dielectric constant medium, the E field is small; voltage drops preferentially across the low (microwave) index material instead of the high index LN.

    “Therefore, in high 𝜖𝜖 medium, 𝐸𝐸 field is small.In other words, voltage drops preferentially across the low (microwave) index material instead of the high index LN.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Some modulator designs have a rapid roll-off at low frequencies, often due to impedance mismatch.

    “Second, some modulator designs have a rapid roll-off at low frequencies, often due to impedance mismatch.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Thermal-optic phase shifters can be used for DC control as well; they are more stable and compact, but at the expense of static power dissipation.

    “Thermal-optic phase shifters can be used for DC control as well.They more stable and compact [16], but at the expense of static power dissipation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [16] Xu, 2020, Nat. Commun. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    In most dual-comb demonstrations, the two combs are generated from separate sources, and establishing mutual coherence can be technically challenging.

    “In most demonstrations, the two combs are generated from separate sources (e.g., mode-locked lasers), and establishing a mutual-coherence could be technically challenging.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    To enhance the E-field in the LN waveguide, it is beneficial to have partially etched waveguides and place the electrodes directly on the slab.

    “To enhance the E-field in the LN waveguide, it is beneficial to have partially etched waveguides and place the electrodes directly on the slab.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The dual-comb measurement of the acetylene gas cell had a residual of 10% and a standard deviation of 3.4% relative to the HITRAN database.

    “A residual (difference between the measured spectrum and the HITRAN database [253]) of 10% and a standard deviation of 3.4% was reported.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [253] Dutt, 2018, Sci. Adv. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    In commercial LN modulators, it is common to have separate DC bias electrode and feedback circuit to stabilize the operation.

    “In commercial LN modulators, it is common to have separate DC bias electrode and feedback circuit to stabilize the operation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The flexibility of resonant EO combs allows pumping at different wavelengths and generating multiple combs simultaneously.

    “This flexibility allows pumping at different wavelengths and generating multiple combs simultaneously.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    The bandwidth of LNOI resonant EO combs can be improved in the future using resonators with higher Q factors.

    “Second, the bandwidth can be future improved using resonators with higher Q factors.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Dual-comb spectroscopy is an emerging technique based on Fourier transform spectroscopy with no moving parts.

    “Dual-comb spectroscopy [250] is an emerging technique based on Fourier transform spectroscopy [251] with no moving parts.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [250] Yan, 2017, Light Sci. Appl. source

      Not checked in the free run.

    • cites [251] Kochanov, 2019, J. Quant. Spectrosc. Radiat. Transfer source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Measurements of DC/low-frequency VπL in monolithic (dry-etched) LNOI MZMs at telecom wavelength typically range from 2.1 to 2.5 V-cm, and can reach 1.8 V-cm with 3.5 μm electrode gap.

    “Measurements of DC/low-frequency 𝑉𝑉 𝜋𝜋 𝐿𝐿 in monolithic (dry-etched) LNOI MZMs (at telecom wavelength) typically range from 2.1 to 2.5 V-cm [16,21,22], and can reach, for example, 1.8 V-cm with 3.5 μm electrode gap [85].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [16] Xu, 2020, Nat. Commun. source

      Not checked in the free run.

    • cites [21] Wang, 2018, Nature source

      Not checked in the free run.

    • cites [22] He, 2019, Nat. Photonics source

      Not checked in the free run.

    • cites [85] Wang, 2018, Opt. Express source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    LNOI waveguides feature compact mode areas and allow small electrode gaps; typical X/Y-cut modulators can support CPW gaps as small as ~5 μm.

    “LNOI waveguides feature compact mode areas and allow small electrode gaps.Typical X/Ycut modulators can support CPW gaps as small as ~5 μm.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Further reducing the electrode gap typically leads to excess optical absorption and microwave loss, and requires more precise alignment in fabrication.

    “Further reducing the gap typically leads to excess optical absorption and microwave loss, and requires more precise alignment in fabrication.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    A cladding material with high RF index but low optical index is highly desirable for reducing Vπ.

    “Furthermore, a cladding material with high RF index but low optical index is highly desirable for this purpose.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    Although LN possesses one of the largest EO coefficients among other materials, the absolute index modulation under a reasonable voltage is still weak; for instance, an electric field of 10^5 V/m can only induce an index change of 1.4×10^-5.

    “Though LN possesses one of the largest EO coefficients among other materials, the absolute index modulation under a reasonable voltage is still weak.For instance, an electric field of 10 5 V/m can only induce an index change of 1.4×10 -5 .”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Wider waveguides also allow wider electrode gap (given the same Vπ), which can reduce microwave loss of the electrode and increase bandwidth.

    “It is worth mentioning that wider waveguides also allow wider electrode gap (given the same 𝑉𝑉 𝜋𝜋 ), which can reduce microwave loss of the electrode and increase bandwidth (as discussed in the following subsections).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    In traveling-wave modulators, three key design considerations are particularly important: (1) velocity matching, (2) impedance matching, and (3) microwave loss.

    “In traveling-wave modulators, three key design considerations are particularly important: (1) velocity matching, (2) impedance matching, and (3) microwave loss.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    In practice, velocity mismatch matters more at higher frequencies; it is therefore appropriate to match the microwave effective index to the optical group index towards the highest target modulation frequency.

    “In practice, velocity mismatch matters more at higher frequencies.It is therefore appropriate to match the microwave effective index to the optical group index towards the highest target modulation frequency.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Placing a phase modulator in an optical cavity can enhance phase modulation efficiency by the number of passes through the modulator, which can increase comb bandwidth.

    “By placing a phase-modulator in an optical cavity, phase modulation efficiency can be enhanced by the number of passes (determined by the Finesse of the cavity) of the light through the modulator, which could increase the comb bandwidth.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    An acetylene gas-cell at atmospheric pressure was interrogated in this dual-comb setup, and its transmittance and dispersion were measured.

    “An acetylene gas-cell at atmospheric pressure was interrogated in this dual-comb setup, and its transmittance and dispersion were measured.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [250] Yan, 2017, Light Sci. Appl. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Not all cavity EO devices use the coupled-ring-resonator approach; other designs exploit neighboring longitudinal or transverse optical modes of a single optical resonator, but the principle of operation is the same.

    “Not all cavity EO devices use this coupled-ring-resonator approach; other designs exploit neighboring longitudinal [264] or transverse [190,262,265] optical modes of a single optical resonator, but the principle of operation is the same.”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [264] Kjaergaard, 2020, Annu. Rev. Condens. Matter Phys. source

      Not checked in the free run.

    • cites [190] Alferness, 1982, IEEE Trans. Microw. Theory Tech. source

      Not checked in the free run.

    • cites [262] Witmer, 2020, Quantum Sci. Technol. source

      Not checked in the free run.

    • cites [265] Awschalom, 2021, PRX Quantum source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    This bi-directionality allows the device to be reconfigured as a tunable frequency beam splitter, in which the splitting ratio and frequency are controlled by microwave power and frequency, respectively.

    “This bi-directionality allows the device to be reconfigured as a tunable frequency beam splitter, in which the splitting ratio and frequency are controlled by microwave power and frequency, respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    Grooves induce periodic modulation in effective index and nonlinear coefficient, providing momentum kick to compensate phase mismatch, but cause Bloch scattering loss; deeper grooves give higher efficiency but larger loss.

    “This change of the waveguide width induces periodic modulation in both the effective index and nonlinear coefficient along the propagation direction, providing a momentum "kick" that compensates for the phase mismatch.The added grooves, however, causes Bloch scattering loss.In general, deeper grooves result in higher nonlinear conversion efficiency due to tighter confinement, but cause larger”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [117] Wang, 2017, Opt. Express source

      Not checked in the free run.

    • cites [321] Guo, 2016, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Compared to type-I SHG when the c-axis is the symmetry axis, CPM enables a much broader phase matching bandwidth but sacrifices conversion efficiency.

    “As compared to the type-I SHG when the caxis is the symmetry axis, CPM can enable a much broader phase matching bandwidth (only certain discrete wavelengths would satisfy phase matching within this bandwidth) but at a sacrifice of conversion efficiency.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [317] Fürst, 2016, Opt. Express source

      Not checked in the free run.

    • cites [318] Wang, 2017, Nat. Commun. source

      Not checked in the free run.

    • cites [319] Rao, 2017, Appl. Phys. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Superconducting quantum devices have demonstrated rapid progress in recent years, which has encouraged interest in using them to create large-scale networks.

    “Such superconducting quantum devices have demonstrated rapid progress in recent years [266], which has encouraged interest in using them to create large-scale networks.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [266] Lauk, 2020, Quantum Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Ultra-low-loss nanophotonic waveguides and high-Q resonators in thin-film LN offer the possibility of realizing long-lived photonic states, and the strong EO effect with highly confined optical modes enables efficient photonic transition.

    “The ultra-low-loss nanophotonic waveguides and high-Q resonators [11] offer the possibility of realizing long-lived photonic states, and the strong EO effect in conjunction with the highly confined optical modes enables efficient photonic transition.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] Zhang, 2017, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Microwave-frequency photons used to encode information in superconducting devices are susceptible to strong thermal noise and attenuation at room temperature, which limits the practical size of such networks to something that can fit within a single cryogenic environment.

    “However, the microwave-frequency photons used to encode information in these devices are susceptible to strong thermal noise and attenuation at room temperature, which limits the practical size of such networks to something that can fit within a single cryogenic environment.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    Bulk lithium niobate whispering gallery mode resonators benefit from low-loss optical modes with quality factor up to ~10^8, but their large size means the EO interaction strength is comparatively weak.

    “These devices benefit from low-loss optical modes (quality factor up to ~10 8 ), but the large size of the devices mean that the EO interaction strength is comparatively weak.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    In metasurface-assisted SHG, a unidirectional phase gradient couples SH into higher-order spatial modes, preventing back-conversion and down-conversion, resulting in unidirectional power transfer and broadband enhancement of SHG efficiency even without phase matching.

    “The unidirectional effective wavevector created by the dielectric metasurface prevents these SH signals from converting back to their fundamental TE modes, and the small mode overlap between these higher-order SH modes and fundamental pump modes prevents them from down-converting to 𝜔𝜔.Therefore, even in the absence of phase matching, the power transfer from the pump to SH is unidirectional, which”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    A photonic two-level system requires two optical resonance modes that are strongly coupled, so photons can transition from one mode to another before being dissipated or lost.

    “In general, a photonic twolevel system requires two optical resonance modes that are strongly coupled, so photons can transition from one mode to another before being dissipated or lost.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    At 50% duty cycle, no phase modulation should be observed when an electric field is applied across the waveguide along the Z crystal axis.

    “In principle, at 50% duty cycle, no phase modulation should be observed when an electric field is applied (through a separate set of electrodes than the poling electrodes) across the waveguide, along Z crystal axis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Nanophotonic PPLN waveguides allow conversion efficiencies comparable to bulk PPLN with a much shorter PPLN section, which is desirable for compactness and broader phase matching bandwidth.

    “Thus, nanophotonic PPLN waveguides allow one to achieve conversion efficiencies comparable to those of bulk PPLN with a much shorter PPLN section.This is desirable not only for its compactness, but also because the phase matching bandwidth will be broader, as the phase matching bandwidth is inversely proportional to interaction length.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Combining electro-optically active optical resonators with low-loss microwave cavities (cavity electro-optics) can enable strong interactions between microwave and optical fields and create nearly quantum-limited modulation performance.

    “Combining electro-optically active optical resonators with low-loss microwave cavities -an approach known as cavity electro-optics [259-261] -can enable strong interactions between microwave and optical fields and create nearly quantum-limited modulation performance.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [259] Tsang, 2011, Phys. Rev. A source

      Not checked in the free run.

    • cites [260] Ilchenko, 2003, J. Opt. Soc. Am. B source

      Not checked in the free run.

    • cites [261] Soltani, 2017, Phys. Rev. A source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Thin-film LN offers relatively low loss (Q-factor up to ~10^7) and smaller optical modes, which can allow for a stronger EO interaction.

    “Thin-film LN offers relatively low loss (Q-factor up to ~10 7 [11]) and smaller optical modes, which can allow for a stronger EO interaction.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] Zhang, 2017, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    The coupled-ring shifter allows bidirectional frequency exchange of photons (frequency swap operation), unlike conventional single sideband modulators.

    “Different from conventional single sideband modulators, the coupled-ring shifter allows bidirectional frequency exchange of photons (i.e., frequency swap operation).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The first cavity EO devices were based on bulk lithium niobate whispering gallery mode resonators.

    “The first cavity EO devices were based on bulk lithium niobate whispering gallery mode resonators, like that shown in Figure 19(c) [261,262,265].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [261] Soltani, 2017, Phys. Rev. A source

      Not checked in the free run.

    • cites [262] Witmer, 2020, Quantum Sci. Technol. source

      Not checked in the free run.

    • cites [265] Awschalom, 2021, PRX Quantum source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Extending the generalized critical coupling condition to a multilevel system is proposed and can lead to cascaded frequency shifting beyond 100 GHz using only several tens of GHz microwave drive.

    “In addition, extending the generalized critical coupling condition to multilevel system is also proposed [177], which can lead to cascaded frequency shifting beyond 100 GHz using only several tens of GHz microwave drive.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [177] Jiang, 2020, Nat. Commun. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In-situ monitoring by injecting CW telecom light and monitoring the second harmonic signal as poling proceeds has been used to optimize poling schedules by poling and depoling until the second harmonic signal saturates.

    “Another in-situ monitoring technique is to inject CW telecom light into a waveguide and monitor the second harmonic signal at the outcoupled light as poling proceeds.This has been used to optimize poling schedules by e.g.poling and depoling a waveguide multiple times until the second harmonic signal was saturated [310].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [310] Zhao, 2020, J. Appl. Phys. source

      Not checked in the free run.

  • May combine two claims. The quote only partly states this claim.

    Interpretationreasoning

    Thin-film LN nano-waveguides offer high optical confinement, leading to A_eff more than an order of magnitude smaller than weakly confined RPE LN waveguides, opening opportunities for low-power χ(3) processes.

    “The recent advancement on the thin-film LN nano-waveguides offers high optical confinement over the wavelength scale (~µm), leading to the 𝐴𝐴 eff more than an order of magnitude smaller than the mode size of weakly confined reverse proton exchange (RPE) LN waveguides.Therefore, thin-film-LNbased cascaded second-order process opens up exciting opportunities, including realizing dynamical processes”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Conversion efficiency in LN photonic crystals remains low (current record 0.078%/W) because fundamentals and harmonics are not on resonance simultaneously.

    “So far, the conversion efficiency remains low (current record of 0.078%/W [143]), since the fundamentals and harmonics (or sum-frequency) are not on resonance simultaneously.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [143] Wang, 2018, Opt. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    4/5 octave-spanning Kerr combs have been reported in a-Z-cut LN microresonator with 335 GHz line spacing, achieved by engineering waveguide-ring coupling to raise Raman oscillation threshold and using large FSR.

    “Recently, 4/5 octave-spanning Kerr combs have been reported in a-Z-cut LN microresonator with a 335 GHz line spacing [340].It is achieved by engineering the waveguidering coupling to raise the Raman oscillation threshold [341] and utilizing a relatively large FSR.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [340] Huang, 2014, Opt. Mater. Express source

      Not checked in the free run.

    • cites [341] Huang, 2013, Opt. Mater. Express source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The first SHG in LN photonic crystals was demonstrated in free-standing L3 photonic crystals from bulk LN; later LNOI wafers realized 1D and 2D photonic crystals with SHG and SFG.

    “The first SHG in LN photonic crystals was demonstrated in a free-standing L3 LN photonic crystals fabricated from bulk LN substrate [180].Subsequently, LNOI wafers were utilized to realize both 1D [181] and 2D photonic crystals [143] and to demonstrate SHG as well as SFG.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [180] Jiang, 2019, Optica source

      Not checked in the free run.

    • cites [181] Li, 2019, Optica source

      Not checked in the free run.

    • cites [143] Wang, 2018, Opt. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    SPDC has been demonstrated on thin-film LN platform in microdisks, PPLN waveguides, and PPLN ring.

    “In addition to demonstrations of classical 𝜒𝜒 (2) wavelength conversion processes, spontaneous parametric downconversion (SPDC), an exclusively quantum process in which a pair of photons is generated from a single pump photon, has also been demonstrated on the thin-film LN platform in microdisks [159], PPLN waveguides [32][33][34]325] and PPLN ring [326].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [159] Hao, 2017, Photon. Res. source

      Not checked in the free run.

    • cites [32][33][34]325]

      Not checked in the free run.

    • cites [326] Stegeman, 1996, Opt. Quantum Electron. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Chen et al. demonstrated a periodically poled racetrack resonator on X-cut MgO-doped LN with QPM SHG efficiency of 230%/mW, corresponding to 10^-6 per single photon.

    “In 2019, Chen et al. demonstrated a periodically poled racetrack resonator on X-cut MgO-doped LN thin films [30] (see Figure 28(a)).The poling is applied on one of the 300 μm straight waveguide sections.This configuration allows all waves to be in their fundamental quasi-TE modes and utilizes the largest nonlinear coefficient 𝑑𝑑 33 .Quasiphase-matched SHG with conversion efficiency of 230%/mW is”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [30] Chen, 2019, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    χ(2) frequency conversion has been demonstrated in unpoled LN ridge waveguides with type-I modal phase matching, sacrificing efficiency but having higher thermal tuning range.

    “Additionally, 𝜒𝜒 (2) frequency conversion has also been demonstrated in unpoled LN ridge waveguides with type-I modal phase matching [299].Such a configuration sacrifices conversion efficiency as it uses a smaller component of the 𝜒𝜒 (2) tensor, and has lower mode overlap 𝜁𝜁, but has a higher thermal tuning range than phase matching done in the type-0 polarization configuration.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [299] Gopalan, 1998, Appl. Phys. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In high-Q ring-shaped whispering gallery resonators, a mixture of nonlinear processes was observed, including SHG, cascaded Raman scattering, and SFG; periodic poling improved SHG efficiency to 0.09%/mW.

    “In addition, in high-Q (3×10 6 at 976 nm), large (200 μm diameter) and wide (7 μm) ring-shaped whispering gallery resonators, a mixture of nonlinear processes were observed, including SHG of the pump light, cascaded stimulated Raman scattering, SHG of the Raman signal, and SFG between the pump and Raman signal [94].Periodic poling was also applied to this Z-cut onchip whispering gallery resonators”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [94] Wolf, 2017, Opt. Express source

      Not checked in the free run.

    • cites [169] Chen, 2018, OSA Continuum source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In X-cut LN microdisks, cyclic phase matching is commonly used, with fundamentals in quasi-TE and SH in quasi-TM.

    “In X-cut LN microdisks, cyclic phase matching is commonly involved [153,159,164], where the fundamentals are quasi-TE modes and second harmonic is at a quasi-TM mode.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [153] Fang, 2019, Opt. Lett. source

      Not checked in the free run.

    • cites [159] Hao, 2017, Photon. Res. source

      Not checked in the free run.

    • cites [164] Jiang, 2016, Sci. Rep. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Effective quasi-phase matching can be achieved in X-cut microdisks with all waves in quasi-TE modes, interacting through d33 with oscillating sign; SHG efficiency 9.9%/mW and THG 1.05%/mW^2 were measured.

    “An effective quasi-phase matching can also be achieved in X-cut microdisks when all waves are at quasi-TE modes, interacting through 𝑑𝑑 33 but with an oscillating sign.Under this scheme, SHG with an efficiency of 9.9%/mW and THG with an efficiency of 1.05%/mW 2 were measured [151].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [151] Ye, 2020, Opt. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Effective third-order nonlinear phenomena have been observed as a result of cascaded χ(2) processes, e.g., THG via cascaded SHG and SFG, and FWM via cascaded SHG and DFG.

    “Furthermore, effective third-order nonlinear phenomena have been observed as a result of cascaded 𝜒𝜒 (2) processes.For example, thirdharmonic generation has been demonstrated through cascaded SHG and SFG [150,151]; effective four-wave mixing (𝜒𝜒 (3) process) has been demonstrated as a result of cascaded SHG and DFG [161].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [150] Lin, 2019, Phys. Rev. Lett. source

      Not checked in the free run.

    • cites [151] Ye, 2020, Opt. Lett. source

      Not checked in the free run.

    • cites [161] Hao, 2020, Photon. Res. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The same group improved the Z-cut PPLN microring with a 2.95 μm poling period, enabling QPM SHG with all waves in fundamental quasi-TM modes to utilize d33, achieving record high 5,000%/mW efficiency and single-photon nonlinearity approaching 1%.

    “More recently, the same group further improved the Z-cut PPLN microring and realized a poling period of 2.95 μm [168].This allowed for QPM SHG with all waves in their fundamental quasi-TM modes to utilize 𝑑𝑑 33 .As a result, record high SHG efficiency of 5,000%/mW was achieved in the low-power regime, reaching a single-photon nonlinearity approaching 1%.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [168] Wolf, 2018, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Entangled photon pairs from SPDC can be used as heralded single photons, but spectral purity has yet to be demonstrated on thin-film LN.

    “Entangled photon pairs generated via SPDC can also be used as sources of heralded single photons, though the spectral purity of the heralded photon has yet to be demonstrated on thin-film LN [34].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Zhao, 2020, Phys. Rev. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Photonic crystals support high Q (~10^5) and ultra-small mode volume, strongly enhancing optical interactions.

    “Photonic crystals support high quality factor (~10 5 ) while maintaining ultra-small mode volume ~ (𝜆𝜆/𝑛𝑛) 3 .They strongly enhance optical interactions and are ideal for nonlinear photonic applications.”
    Quote in the paperNot a substantial claim

  • May combine two claims. The quote only partly states this claim.

    Premisecitation

    Periodic poling has been applied to Z-cut LN microdisks, achieving poling period ~2 μm and later dual-period poling with 90 nm domain size, observing SHG, THG, and FHG, but conversion efficiency remains moderate (0.05%/mW).

    “Recently, periodic poling has also been applied to Z-cut LN microdisks [162].With a bottom layer acting as a poling electrode, piezoresponse force microscopy was used to achieve a poling period of ~2 μm.Using the piezoresponse force microscopy method, the same group further demonstrated dual-period poling with unit domain size as small as 90 nm in width, and observed SHG, THG, and even FHG [163].H”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [162] Zhang, 2020, Opt. Lett. source

      Not checked in the free run.

    • cites [163] Eichenfield, 2017 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Stable soliton combs in TE mode of Z-cut LN have been achieved by generating combs along non-polar axis or at longer wavelengths where Raman is weaker.

    “The former two solutions have been used to achieve stable soliton combs in the TE mode of Z-cut LN [27,174].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [27] He, 2019, Optica source

      Not checked in the free run.

    • cites [174]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Photons generated via SPDC in PPLN waveguides exhibit strong energy-time entanglement, enabling entangled photon pairs in multiple wavelength channels; demonstrated over >120 nm separation.

    “Photons generated via SPDC in PPLN waveguides generally exhibit strong energy-time entanglement, which can be leveraged to produce entangled photon pairs in multiple wavelength channels to enable frequency domain multiplexing; this has been demonstrated in a submillimeter PPLN waveguide with signal-idler pairs generated over a coarse wavelength division multiplexing grid separated by more than 120”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Elkus, 2019, Opt. Express source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The combination of optimized χ(2) performance and maximized Raman gain in the same polarization causes a conundrum in Kerr comb generation, as strong Raman effect can prevent soliton modelocking.

    “The combination of optimized 𝜒𝜒 (2) performance and maximized Raman gain in the same polarization has caused a conundrum in functional Kerr comb generation, as the strong Raman effect can prevent soliton modelocking.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Luo et al. demonstrated telecom-to-visible SHG with 1.5%/mW efficiency and DFG at telecom wavelengths in Z-cut microrings.

    “With this approach, Luo et al. demonstrated telecom to visible SHG with a conversion efficiency of 1.5%/mW as well as DFG at telecom wavelengths [173].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [173] Zhang, 2019, Nat. Photonics source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    The key advantage of resonance-enhanced χ(2) conversion relies on circulating optical waves; in doubly resonant and critically coupled conditions, efficiency enhancement scales as ∼Q1^2 Q2.

    “Most importantly, the key advantage of resonance-enhanced 𝜒𝜒 (2) wavelength conversion relies on its capability of circulating the optical waves.In doubly resonant and critically coupled conditions, the conversion efficiency enhancement can scale as ∼ 𝑄𝑄 1 2 𝑄𝑄 2 .”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The Raman effect is strongest when light is polarized along the crystal's Z-axis and competes with FWM used to generate comb teeth.

    “The Raman effect is strongest when the light is polarized along the crystal's Z-axis [175] and competes with the four wave mixing process used to generate the comb teeth.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [175] Holzgrafe, 2020, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Recent development of piezo-optomechanics further links elastic waves and microwaves on thin film piezoelectric materials.

    “The recent development of piezooptomechanics further links elastic waves and microwaves on thin film piezoelectric materials.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    LN thin film on diamond could achieve mechanical frequencies of >40 GHz, taking advantage of the high acoustic velocity in diamond (19 km/s in bulk diamond vs 8 km/s in bulk LN).

    “taking advantage of the high acoustic velocity in diamond (19 km/s in bulk diamond, vs 8 km/s in bulk LN), LN thin film on diamond could achieve mechanical frequencies of >40 GHz.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Oxide is not a good thermal conductor, and thus limits stability of devices under high RF power inputs.

    “Also, oxide is not a good thermal conductor, and thus limits the stability of devices under high RF power inputs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Most published work selected crystal orientation of LN thin film based on commercial availability, but optimal device orientations might be different for piezoelectric and optomechanical couplings, so devices can have two parts with different orientations connected by an acoustic waveguide.

    “While most published work selected the crystal orientation of LN thin film based on its commercial availability, the optimal device orientations might be difference for piezoelectric and optomechanical couplings, and thus piezo-optomechanical devices can have two parts with different orientations and then be connected using an acoustic waveguide [170].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [170] Luo, 2019, Phys. Rev. Appl. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Other piezoelectric materials with stronger piezoelectricity and/or photoelasticity, such as PZT and TeO2, could further improve efficiency of piezo-optomechanical devices if high quality thin film with low optical loss is available.

    “Other piezoelectric materials with stronger piezoelectricity and/or photoelasticity, such as PZT and TeO2, could further improve the efficiency of piezo-optomechanical devices, should high quality thin film with low optical loss be available.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Optical waveguide structure defined on LN thin film can scatter thin film acoustic waves, especially when acoustic wavelength becomes comparable to structure feature sizes, so such devices usually work at sub-GHz acoustic frequencies and have limited Q and fQ product.

    “However, similar to the overlay waveguides on bulk LN substrate, the optical waveguide structure defined on the LN thin film can scatter the thin film acoustic waves, especially when the acoustic wavelength becomes comparable to the structure feature sizes (e.g.etch depth).Thus, such devices usually work at sub-GHz acoustic frequencies and have limited Q and fQ product for the acoustic resonance.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    This potentially leads to strong energy transfer from pump to Stokes light if high optical power is used for other parametric oscillation such as SHG or in EO-based LN devices.

    “This potentially leads to a strong energy transfer from the pump to the Stokes light if high optical power is used for other parametric oscillation such as second harmonic generation or in EO-based LN devices.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Since piezo-optomechanical coupling strength depends on both piezoelectric and photoelastic tensors, design of piezo-optomechanical devices is challenging.

    “Since the piezo-optomechanical coupling strength depends on both the piezoelectric and photoelastic tensors, the design of piezo-optomechanical devices is challenging.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The strongest Raman gain is found when pump polarization is parallel to the crystal axis, where EO and second-order nonlinear effects are also largest.

    “The strongest Raman gain is found when the polarization of the pump is parallel to the crystal axis, where both the electro-optic (EO) and second order nonlinear effects are also the largest.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [175] Holzgrafe, 2020, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Compared to suspended thin-film LN, LNOI can handle larger RF powers; up to ~100 mW microwave power is delivered to suspended LN thin films, while more than 1 W is delivered when thin-film LN is on oxide layer.

    “Compared to suspended thin-film LN, LNOI can handle larger RF powers.For example, through similar IDT structures, up to ~100 mW microwave power is delivered to the suspended LN thin films, while more than 1 W microwave power is delivered when thin-film LN is laying on the oxide layer [396].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [396] Cai, 2019, Low-loss waveguides in Y-cut thin film lithium niobate for acousto-optic applications source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Piezoelectrically generated acoustic waves in LN could efficiently drive spin qubits of color centers in diamond.

    “Piezoelectrically generated acoustic waves in LN could efficiently drive the spin qubits of color centers in diamond.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    While optical fields in LN with X or Y polarization have the same ordinary refractive index, acoustic phase velocities in X, Y, and Z directions are all different.

    “While optical fields in LN with X or Y polarization have the same ordinary refractive index, the acoustic phase velocities in the X, Y, and Z directions are all different.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Dispersive wave generation is a phase-matched nonlinear process where energy is transferred across a zero-GVD point, commonly used to extend spectral bandwidth.

    “Dispersive wave generation is a phase-matched nonlinear process where energy from the pump is transferred across a zero-GVD point, and is commonly used to extend the overall generated spectral bandwidth [383][384][385].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [383][384][385]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Due to anisotropy of LN, SAW devices use a variety of crystal orientations such as X, Z, 42°-Y, 128°-Y.

    “Due to the anisotropy of LN, SAW devices use a variety of crystal orientations such as X, Z, 42°-Y, 128°-Y.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Rayleigh modes are not the most effective modes for optomechanical coupling due to their strain profile; top of thin film sees tensile strain and bottom compressive, and induced optical index changes would be partially cancelled out in overlap integration with optical mode.

    “However, Rayleigh modes are not the most effective modes for optomechanical coupling due to their strain profile.The top of the thin film sees a tensile strain and the bottom sees a compressive strain, and the induced optical index changes would be partially cancelled out in the overlap integration with the optical mode.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In simulations of a 0.5-cm-long dispersion-engineered LN waveguide, second and third harmonic components were immediately generated, main pulse underwent spectral broadening via self-phase modulation, and for z > 4 cm a dispersive wave near 860 nm was generated and blue-shifted.

    “As the pulse propagates in the waveguide, the second harmonic and third harmonic components were immediately generated.The main pulse undergoes spectral broadening through self-phase modulation.For z > 4 cm, a dispersive wave component is generated near 860 nm which continues to blue shift due to phase matching and approaches the second harmonic component.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [296] Luo, 2019, Laser Photon. Rev. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Point defects in SiC have been explored for acoustic wave-spin interactions.

    “Point defects in SiC have also been explored for acoustic wave-spin interactions [391].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [391]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    TeO2 is widely used in bulk acousto-optic modulators for its excellent acousto-optic properties, but nanofabrication of TeO2 is challenging and needs further development.

    “TeO 2 is widely used in bulk acousto-optic modulators (AOMs) for its excellent properties for acousto-optics, but nanofabrication of TeO 2 is challenging and needs further development [387,388].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [387] Whiteley, 2019, Nat. Phys. source

      Not checked in the free run.

    • cites [388] Campbell, 1989

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    This particular shear acoustic mode employs high piezoelectric coefficient d24=d15 and high photoelastic coefficient p14, and features higher acoustic velocity than Rayleigh-like modes, increasing acoustic frequency.

    “This particular shear acoustic mode, whose major strain component is 𝑒𝑒 𝑌𝑌𝑌𝑌 (index 4 in the reduced representation), employs the high piezoelectric coefficient 𝑑𝑑 24 = 𝑑𝑑 15 , and high photoelastic coefficient 𝑝𝑝 14 .It also features a higher acoustic velocity than the Rayleigh-like modes, and thus increases the acoustic frequency of the devices.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Integrated piezo-optomechanical devices utilize electrically-driven acoustic waves to deflect, modulate, and frequency control light and demonstrate superior performance than conventional bulk acousto-optic components.

    “Such integrated piezo-optomechanical devices utilize electrically-driven acoustic waves to deflect, modulate, and frequency control the light and demonstrate superior performance than conventional bulk acousto-optic components.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In that work, spectral components in the visible were generated through SHG and sum-frequency generation, along with cascaded SHG allowing spectral generation down to the UV regime.

    “The spectral components in the visible were generated through SHG and sum-frequency generation, along with cascaded SHG which allows for spectral generation down to the UV regime.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [297] Luo, 2018, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    LN SAW technology has been developed for several decades for mobile communication systems, providing valuable experience and insight into design of piezo-optomechanical devices.

    “Fortunately, LN surface acoustic wave (SAW) technology has been developed for several decades for its use in mobile communication systems [392] , which provides valuable experience and insight into the design of piezo-optomechanical devices.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [392] Cheng, 1992, Appl. Phys. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    This approach utilizes quasi-phase matched χ2 interactions to enable broadband SHG with 3-dB bandwidths >110 nm and effective self-phase modulation with nonlinearities 200 times larger than the intrinsic χ3 nonlinearity in LN.

    “This approach utilizes quasi-phase matched 𝜒𝜒 (2) interactions to enable broadband SHG with 3-dB bandwidths >110 nm and effective self-phase modulation with nonlinearities that are 200 times larger than the intrinsic 𝜒𝜒 (3) nonlinearity in LN.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [295] Jankowski, 2020, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Piezo-optomechanical coupling between superconducting qubits and optical cavities using AlN on Si has been achieved, benefiting from the silicon optomechanics platform.

    “Piezo-optomechanical coupling between superconducting qubits and optical cavities using AlN on Si has been achieved [390], benefiting from the well-developed silicon optomechanics platform.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [390] Mayor, 2021, Phys. Rev. Appl. source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    The optical contrast formed by Ti indiffusion is limited, so optical mode size is large, for example, 10 μm.

    “However, the optical contrast formed by Ti indiffusion is also limited, and thus the optical mode size is large, for example, 10 μm.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    SAWs on bulk LN substrates are low-loss propagating elastic waves confined to the surface of LN, efficiently generated by interdigital transducers.

    “SAWs on bulk LN substrates are low-loss propagating elastic waves confined to the surface of LN, which can be efficiently generated by interdigital transducers (IDTs).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In the integrated LN f-2f interferometer, the waveguide output was directly sent to a silicon avalanche photodiode for fCEO detection and a feedback loop was implemented for stabilization.

    “The waveguide output was directly sent to a silicon avalanche photodiode for f CEO detection and a feedback loop was implemented for stabilization.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [296] Luo, 2019, Laser Photon. Rev. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Bulk LN substrates cannot confine optical modes, so Ti indiffused layers, deposited higher optical index materials, or material-on-oxide layers are needed to guide optical light on chip.

    “However, bulk LN substrates cannot confine optical modes.Thus, Ti indiffused layers, deposited higher optical index materials, or material-on-oxide layers are needed to guide the optical light on the chip.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Overlay layers on bulk LN can be used to guide light while SAW generation and propagation remain mainly in LN substrate; such devices do not rely on LNOI wafers and feature more robust and compatible fabrication avoiding etching of LN.

    “To improve interaction between optical and acoustic waves, overlay layers on bulk LN can be used to guide the light, while the generation and propagation of the SAW are still mainly in the LN substrate.Such devices do not rely on LNOI wafers, and feature a more robust and compatible fabrication that avoids etching of LN.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Among commonly used piezoelectric materials ZnO, AlN, GaAs, and LN, LN shows the highest piezoelectric coefficient, while all have similar photoelasticity and have been used to demonstrate high-Q optical cavities.

    “While all these materials have similar photoelasticity, and have been used to demonstrate high-Q optical cavities, LN shows the highest piezoelectric coefficient.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Recently developed integrated LN acousto-optic frequency shifters employ free-space regions and achieve high purity frequency shifting.

    “Recently developed integrated LN acousto-optic frequency shifter (AOFS) [396,401] employ such "free-space" regions and achieve high purity frequency shifting.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [396] Cai, 2019, Low-loss waveguides in Y-cut thin film lithium niobate for acousto-optic applications source

      Not checked in the free run.

    • cites [401] Shao, 2020, Acoustically mediated microwave-to-optical conversion on thin-film lithium niobate

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Propagation loss of SAWs on bulk LN is typically 1-7 dB/mm at GHz frequencies at room temperature, and about one order of magnitude lower at cryogenic temperatures.

    “The propagation loss is typically 1-7 dB/mm at GHz frequencies at room temperature, and about one order of magnitude lower at cryogenic temperatures [393,394].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [393] Shao, 2020, Opt. Express source

      Not checked in the free run.

    • cites [394] Cai, 2019, Photon. Res. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Thin-film LN is a promising platform for quantum information processing, but material itself does not offer memories, detectors and deterministic sources.

    “On the other hand, thin-film LN is a promising platform for quantum information processing, but the material itself does not offer memories, detectors and deterministic sources.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Optomechanical crystals have been developed on suspended LN; periodic structures provide bandgaps for both light and acoustic waves, while resonators are formed by introducing defect modes within the bandgap.

    “Optomechanical crystals [142,170,182] have also been developed on suspended LN.Periodic structures provide bandgaps for both light and acoustic waves, while resonators are formed by introducing defect modes within the bandgap, for example, by introducing a perturbation to the periodic unit cell.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [142] Li, 2019, Laser Photon. Rev. source

      Not checked in the free run.

    • cites [170] Luo, 2019, Phys. Rev. Appl. source

      Not checked in the free run.

    • cites [182] Li, 2020, Nat. Commun. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Travelling acoustic waves in integrated devices are typically generated by IDTs, whose small feature size limits RF power at about 1 W, while bulk AOFS can handle 10 W of RF power.

    “Second, the travelling acoustic waves in integrated devices are typically generated by IDTs, whose small feature size limits the RF power at about 1 W, while bulk AOFS can handle 10 W of RF power.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Optomechanical crystals feature small optical and acoustic mode volumes and large overlaps between the two modes.

    “Optomechanical crystals feature small optical and acoustic mode volumes and large overlaps between the two modes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    On Ti in-diffused LN waveguides, integrated SNSPDs based on amorphous WSi as well as W TESs have both been demonstrated.

    “On Ti in-diffused LN waveguides, integrated SNSPDs based on amorphous WSi as well as W TESs have both been demonstrated [418,419].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [418] Colangelo, 2020, Superconducting nanowire single-photon detector on thin- film lithium niobate photonic waveguide

      Not checked in the free run.

    • cites [419] Desiatov, 2019, Appl. Phys. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Commercial bulk acousto-optic modulators typically operate at acoustic frequencies below hundred megahertz, though devices featuring gigahertz frequencies have been available with compromised performance.

    “Commercial bulk acousto-optic modulators typically operate at acoustic frequencies below hundred megahertz, though devices featuring gigahertz frequencies have been available with compromised performance.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Currently major limitation for LN on sapphire is availability of high-quality LN on sapphire wafers; bubbles formed between thin-film LN and sapphire during bonding significantly impact usable area to less than 50%.

    “Currently, the major limitation is the availability of high-quality LN on sapphire wafers.Bubbles formed between the thin-film LN and sapphire substrate during the bonding process significantly impact the usable area of LN on sapphire wafer, to less than 50%.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    It is more suitable to pattern the SNSPD after waveguide fabrication, which makes the lithography step for SNSPDs particularly challenging.

    “It is, therefore, more suitable to pattern the SNSPD after waveguide fabrication, which makes the lithography step for SNSPDs particularly challenging.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Thus devices can achieve higher acoustic frequencies (in GHz range) and acoustic Q factors.

    “Thus, devices can achieve higher acoustic frequencies (in the GHz range) and acoustic Q factors.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Both demonstrations employed specially tailored deposition processes for the superconducting thin film to avoid excessive heating, which is incompatible to LN thin films.

    “Furthermore, both demonstrations employed specially tailored deposition processes for the superconducting thin film to avoid excessive heating, which is incompatible to LN thin films [423,424].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [423] Akhlaghi, 2015, Nat. Commun. source

      Not checked in the free run.

    • cites [424] Cheng, 2020, Photon. Res. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Such acousto-optic nonreciprocal devices have been developed on thin film AlN, but achieved efficiency is still much lower than state-of-the-art magnetic bulk optical isolators and circulators.

    “Such acoustooptic nonreciprocal devices have been developed on thin film AlN [406,407].However, the achieved efficiency is still much lower than the state-of-the-art magnetic bulk optical isolators and circulators.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [406] Reed, 2010, Nat. Photonics source

      Not checked in the free run.

    • cites [407] Honardoost, 2019, Opt. Express source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    SNSPDs and TESs are two leading single-photon detection technologies, especially at infrared wavelengths.

    “Superconducting nanowire single-photon detectors (SNSPDs) and transition-edge sensors (TESs) are two leading single-photon detection technologies, especially at infrared wavelengths [412-415].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [412] Cabrera, 1998, Appl. Phys. Lett. source

      Not checked in the free run.

    • cites [413] Miller, 2003, Appl. Phys. Lett. source

      Not checked in the free run.

    • cites [414] Tanner, 2012, Nanotechnology source

      Not checked in the free run.

    • cites [415] Smirnov, 2018, J. Phys. Conf. Ser. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Suspended LN disks support both optical whispering gallery modes and mechanical modes, and have been used to achieve optomechanical coupling, but at relatively low mechanical frequency of 100s of MHz.

    “Suspended LN disks support both optical whispering gallery modes and mechanical modes (Figure 35(a)), and have been used to achieve optomechanical coupling [166], but at a relatively low mechanical frequency of 100s of MHz.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [166] Siew, 2016, IEEE Photon. Technol. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Rib-loaded modulators have not been able to fully utilize CMOS-fabrication facilities, but reduce some process compatibility issues associated with LN etching and can reach similar performances as monolithic ones.

    “Though rib-loaded modulators have not been able to fully utilize CMOS-fabrication facilities, it does reduce some process compatibility issues associated with LN etching, and can reach similar performances as monolithic ones [409].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [409] Ferrari, 2018, Nanophotonics source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    Non-magnetic acousto-optic isolators or circulators are being developed, compatible with magnetic fields and desired for quantum systems.

    “Non-magnetic acousto-optic isolators or circulators are being developed, which are compatible with magnetic fields and desired for quantum systems.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    About 1 W optical light has been successfully coupled from lensed fibers to suspended optical waveguides, and only about 100 mW RF power has been applied to suspended LN acoustic cavities; higher powers could damage suspended LN structures, probably due to localized heating.

    “About 1 W optical light has been successfully coupled from lensed fibers to suspended optical waveguides, and only about 100 mW RF power has been applied to the suspended LN acoustic cavities.Higher powers could damage the suspended LN structures, probably due to the localized heating.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Employing a second optical resonance can enhance microwave to optical conversion efficiency by the ratio between microwave frequency and optical linewidth; such improvements are significant for high Q optical cavities with linewidths of tens of MHz.

    “Similar to double-ring cavity electro-optics (Section 3.5 and 3.6), employing a second optical resonance can enhance the microwave to optical conversion efficiency by the ratio between the microwave frequency and the optical linewidth.Such improvements are significant for high Q optical cavities with linewidths of tens of MHz.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    More recently, hybrid LN (unpatterned)/SiNx MZM have been demonstrated, which is CMOS-compatible and aimed for future integration with SiP photonics.

    “More recently, hybrid LN (unpatterned)/SiNx MZM have also been demonstrated, which is CMOS-compatible and is aimed for future integration with SiP photonics [202].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [202] Bahadori, 2020, Opt. Express source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Bonding of dry-etched thin-film LN modulators on Si photonic circuits was achieved, where splitters/combiners and grating couplers of MZM were all Si, but phase modulation sections, including LN ridge waveguides and metal electrodes, were in LN thin films.

    “Bonding of dry-etched thin-film LN modulators on Si photonic circuits were also achieved, where the splitters/combiners and grating couplers of the MZM were all Si, but the phase modulation sections, including LN ridge waveguides and metal electrodes, were in LN thin films [22].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] He, 2019, Nat. Photonics source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    While LN features strong piezoelectricity, the optomechanical coupling rate of LN devices is smaller than that in state of the art silicon devices, due to lower photoelastic coefficients of LN compared to silicon and limitations in LN fabrication.

    “While LN features strong piezoelectricity, the optomechanical coupling rate of LN devices is smaller than that in the start of the art silicon devices.This is due to the lower photoelastic coefficients of LN compared to silicon, and the limitations in LN fabrication.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    As acoustic waves do not radiate into vacuum, suspended LN thin films are more flexible in design and could achieve higher acoustic frequency and larger Q factors.

    “As acoustic waves do not radiate into vacuum, suspended LN thin films are more flexible in design and could achieve higher acoustic frequency and larger Q factors.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Hybrid devices that use LN and silicon have potential for higher microwave to optical conversion efficiencies, and such hybrid devices using AlN and silicon have been recently demonstrated, though their efficiency is still limited.

    “Hybrid devices that use LN and silicon have the potential for higher microwave to optical conversion efficiencies, and such hybrid devices using AlN and silicon have been recently demonstrated [390], though their efficiency is still limited.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [390] Mayor, 2021, Phys. Rev. Appl. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Optical ring resonators defined by etched optical waveguides benefit from higher Q factors than photonic crystals.

    “Also, optical ring resonators defined by etched optical waveguides benefit from higher Q factors than photonic crystals.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Molecular beam epitaxy growth of LN on sapphire has been demonstrated, opening another pathway for high quality LN on sapphire, although current film quality is still not comparable with Smart-Cut.

    “Molecular beam epitaxy growth of LN on sapphire has been demonstrated [402], and it opens another pathway for high quality LN on sapphire, although the current film quality is still not comparable with ones prepared by the Smart-Cut.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [402] Saleh, 2019

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    On bulk LN substrate, SNSPDs based on polycrystalline NbN have been studied since 2012.

    “On bulk LN substrate, SNSPDs based on polycrystalline NbN have been studied since 2012 [416,417].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [416] Höpker, 2017, Proc. SPIE source

      Not checked in the free run.

    • cites [417] Höpker, 2019, APL Photon. source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    In this approach, full mode transition from Si waveguide to thin-film LN waveguide is possible, offering stronger field confinement in LN compared to bare-film-bonding approach.

    “In this approach, full mode transition from Si waveguide to thin-film LN waveguide is possible (see Figure 36(b)), which offers stronger field confinement in the LN compared to the barefilm-bonding approach.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Thin-film LN waveguide fabrication involves aggressive dry etching and wet cleaning, which will damage superconducting nanowires.

    “However, thin-film LN waveguide fabrication involves aggressive dry etching and wet cleaning, which will damage the superconducting nanowires.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    LN-on-sapphire platform is being employed for better acoustic confinement and better substrate thermal conductivity to handle high RF power.

    “Another is employing the LN-on-sapphire platform (Figure 35(e)) [397] for better acoustic confinement and better substrate thermal conductivity to handle high RF power.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [397] Sarabalis, 2020, APL Photon. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Integrated lasers, amplifiers, linear detectors, as well as driving electronics are desirable in some classical applications, but they are not provided natively by LN.

    “Furthermore, integrated lasers, amplifiers, linear detectors, as well as driving electronics are desirable in some classical applications, but they are not provided natively by LN.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Piezoelectrically driving small acoustic modes in optomechanical crystals is challenging; demonstrated microwave-to-mechanical conversion efficiency is ~0.1% due to small size of electrodes.

    “However, piezoelectrically driving such small acoustic modes is challenging.It can be done using electrodes directly deposited on the optomechanical crystals [182] or by employing an inter-digitated transducer (IDT) on a suspended acoustic waveguide then guided to the crystals [170].Due to the small size of electrodes, the demonstrated microwave-to-mechanical conversion efficiency is ~0.1%.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [170] Luo, 2019, Phys. Rev. Appl. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Size of acousto-optic interaction regions for integrated devices is limited to ~100 μm, while bulk devices can feature a few centimeters.

    “First, the size of acousto-optic interaction regions for the integrated devices are limited to ~100 μm, while bulk devices can feature a few centimeters.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Many mature PIC platforms, such as Si and SiNx, lack χ2 nonlinearity and/or capability of quasi-phase matching.

    “On one hand, many mature photonic integrated circuit (PIC) platforms, such as Si and SiNx, lack 𝜒𝜒 (2) nonlinearity and/or the capability of quasi-phase matching.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    There is still a need to match mechanical resonant frequency and differential frequency between optical resonances, which can be done by DC electro-optic tuning.

    “However, there is still a need to match the mechanical resonant frequency and the differential frequency between the optical resonances, which can be done, for example, by DC electro-optic tuning.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Integrated acousto-optic modulators have been demonstrated featuring even higher acoustic frequencies in gigahertz regime.

    “Meanwhile, integrated acousto-optic modulators have been demonstrated featuring even higher acoustic frequencies in gigahertz regime.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Mobile charge carriers in electro-optic materials can create a wide variety of optical and electrooptical effects, including photoconductivity; these are long-standing problems with LN material and often limit stability and power handling capability of LN devices.

    “Mobile charge carriers in electro-optic materials can create a wide variety of optical and electrooptical effects, including photoconductivity .These are long-standing problems with LN material, and often limit the stability and power handling capability of LN devices.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Time-resolved luminescence revealed consistent fluorescence lifetimes of 157 μs in both thin film and bulk samples, suggesting no additional non-radiative decay pathways were induced by smart-cut.

    “Time-resolved luminescence further revealed consistent fluorescence lifetimes of 157 μs in both the thin film and bulk samples, suggesting no additional non-radiative decay pathways were induced by the smart-cut.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    Thin-film LN could be suited for both time-domain and frequency-domain quantum processing, as fast switches, interferometers, and electro-optic frequency shifters can be achieved in a compact and low-loss platform.

    “Thin-film LN could be suited for both time-domain as well as frequency-domain quantum processing [477], as fast switches, interferometers and electrooptic frequency shifters can be achieved in a compact and low-loss platform.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [477] Soudagar, 2007, J. Opt. Soc. Am. B source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Photorefractive materials experience refractive index changes when exposed to optical power due to excitation of charge carriers from crystal defect sites.

    “Photorefractive materials experience refractive index changes when exposed to optical power due to the excitation of charge carriers from crystal defect sites.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    With growing complexity of optical circuits, additional challenges related to fabrication variation arise, which motivates active tuning of photonic devices.

    “With growing complexity of the optical circuits [471], additional challenges related to fabrication variation arises, which motivates active tuning of photonic devices [472].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [471]

      Not checked in the free run.

    • cites [472] Slussarenko, 2019, Appl. Phys. Rev. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Other methods of mitigation used in bulk LN devices include transition metal doping and operating at elevated temperature.

    “Other methods of mitigation used in bulk LN devices include transition metal doping [462] and operating at elevated temperature [463].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [462] Becker, 1985, Opt. Lett. source

      Not checked in the free run.

    • cites [463] Gee, 1985, Appl. Phys. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    A luminescence spectrum measured using thin film and bulk crystal showed comparable transition linewidths (0.7 nm) and absence of background fluorescence from thin film, indicating smart-cut process does not create additional fluorescent centers that absorb at 773.4 nm excitation.

    “A luminescence spectrum was also measured using the thin film and bulk crystal, showing comparable transition linewidths (0.7 nm) between these samples and absence of background fluorescence from the thin film.This indicates that the smart-cut process does not create any additional fluorescent centers that absorb at the 773.4 nm excitation wavelength used here.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    On Ti in-diffused LN waveguides, GaAs detectors have been demonstrated.

    “On Ti in-diffused LN waveguides, GaAs detectors have been demonstrated [430].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [430] Ellis, 2018, Appl. Phys. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Strong Raman oscillation in LN manifests in the counterpropagating direction with respect to the pump field, effectively coupling the clockwise and counterclockwise modes in the resonator.

    “Additionally, the strong Raman oscillation in LN manifests in the counterpropagating direction with respect to the pump field [175], effectively coupling the clockwise and counterclockwise modes in the resonator.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [175] Holzgrafe, 2020, Optica source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Integrated SNSPDs and amorphous-Si detectors can be fabricated by direct material deposition and patterning on LNOI waveguides.

    “Note that the integrated SNSPDs [420,421] and amorphous-Si detectors [422] discussed here can be fabricated by direct material deposition and patterning on LNOI waveguides.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [420] Sayem, 2020, Appl. Phys. Lett. source

      Not checked in the free run.

    • cites [421] Cheng, 2019, Appl. Phys. Lett. source

      Not checked in the free run.

    • cites [422] Dane, 2017, Appl. Phys. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    In LN, there are multiple approaches to achieve magnetic-free non-reciprocity and on-chip optical isolation.

    “In LN, there are multiple approaches to achieve magnetic-free non-reciprocity and on-chip optical isolation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Recent measurements suggest charge carrier effects are stronger in LNOI than in comparable bulk devices, possibly due to tighter optical confinement and higher crystal defect concentration in LNOI.

    “Recent measurements [183,342,457,458] suggest that these effects are stronger in LNOI than in comparable bulk devices, possibly due to the tighter optical confinement and higher crystal defect concentration in LNOI.”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [183] Boyd, 2019

      Not checked in the free run.

    • cites [342] Sanna, 2015, Phys. Rev. B source

      Not checked in the free run.

    • cites [457] Surya, 2021, Opt. Lett. source

      Not checked in the free run.

    • cites [458] Günter, 2006 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Time-domain quantum processing has been widely used for quantum communication, where temporal modes can propagate long distances in optical fibers, and frequency-domain quantum processing enables parallel and multiplexed operations.

    “The ability to process quantum information in the time domain has been widely used for quantum communication, where the temporal modes can propagate long distances in optical fibers [474], and frequency-domain quantum processing enables parallel and multiplexed operations [258].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [474] Marcikic, 2002, Phys. Rev. A source

      Not checked in the free run.

    • cites [258] Tsang, 2010, Phys. Rev. A source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Nonreciprocal devices, such as isolators and circulators, are critical for signal routing and blocking, as well as laser protection.

    “However, nonreciprocal devices, such as isolators and circulators, are critical for signal routing and blocking, as well as laser protection.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Beam splitters can be achieved by Mach-Zehnder interferometers, which can be tuned to the desired operation point, increasing the number of active devices and optical phase shifters but allowing compensation for defects and fabrication imperfections.

    “As an example, beam splitter can be achieved by Mach-Zehnder interferometers, which can be tuned to the desired operation point, which increases the number of active devices and optical phase shifters, but allows for compensating for defects and fabrication imperfections [473].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [473] Lu, 2019, npj Quantum Inf. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Polarization-dependence of transition dipole moment was consistent despite variations in light polarization owing to racetrack waveguide design, indicating smart-cut process did not add residual strain compared to bulk crystal.

    “Importantly, the polarization-dependence of the transition dipole moment was also consistent despite variations in light polarization owing to their racetrack waveguide design, indicating that the smart-cut process did not add residual strain compared to the bulk crystal.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    Such a broad, stable frequency comb with low repetition rates could be used for applications such as optical frequency synthesizer and high-resolution comb spectroscopy.

    “Such a broad, stable frequency comb with low repetition rates could be used for applications such as optical frequency synthesizer and high-resolution comb spectroscopy.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Time-domain quantum processing employs fast switches, optical delay lines, and unbalanced interferometers as fundamental building blocks, while frequency-domain processing requires spectral filtering and frequency shifting achieved by electro-optic modulation.

    “Time-domain quantum processing employs fast switches, optical delay lines as well as unbalanced interferometers as fundamental building blocks [475], while frequency-domain processing requires spectral filtering, as well as frequency shifting achieved by e.g.electrooptic modulation [476].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [475] Joshi, 2018, Nat. Commun. source

      Not checked in the free run.

    • cites [476] Joshi, 2020, Phys. Rev. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The low propagating loss achieved in thin-film LN is well suited for quantum applications, and the electro-optic effect allows low-loss phase shifters, which could drastically reduce power consumption compared to thermal phase shifters.

    “The low propagating loss achieved in thin-film LN is well suited for quantum applications, and the electro-optic effect allows low-loss phase shifters, which could drastically reduce the power-consumption compared to the use of thermal phase shifters.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    On thin-film platform, metal-semiconductor-metal photodetectors based on amorphous silicon have been reported, featuring responsivity of 22 mA/W to 37 mA/W in 635 nm to 850 nm wavelength range.

    “On the thin-film platform, metal-semiconductor-metal photodetectors based on amorphous silicon have been reported, featuring a responsivity of 22 mA/W to 37 mA/W in the 635 nm to 850 nm wavelength range [422] (see Figure 37(b)).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [422] Dane, 2017, Appl. Phys. Lett. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Thermo-optic tuning can be used as a drift-free method of bias control, but it requires tradeoffs in power dissipation and tuning bandwidth.

    “Thermo-optic tuning can be used as a drift-free method of bias control [16,468], but this requires tradeoffs in power dissipation and tuning bandwidth.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [16] Xu, 2020, Nat. Commun. source

      Not checked in the free run.

    • cites [468] Wang, 2020, Nat. Photonics source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    The thin-film LN platform presents a promising avenue for exploring more complex nonlinear dynamics.

    “the thin-film LN platform presents a promising avenue for exploring more complex nonlinear dynamics.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The role of Raman and the dynamics of counterpropagating EO fields remains largely unstudied.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Heterogeneous integration of magneto-optical materials in integrated photonics is generally difficult to fabricate, incompatible with large scale integration, and associated with high insertion loss.

    “But it is generally difficult to fabricate, incompatible with large scale integration, and associated with high insertion loss.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Conventional semiconductor detectors, such as Si or III-V p-n/p-i-n or avalanche photodiode, will likely require flip-chip bonding.

    “But conventional semiconductor detectors, such as Si or III-V p-n/p-i-n or avalanche photodiode, will likely require flip-chip bonding.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Piezoresponse force microscopy can provide detailed information on the surface but without poling depth information.

    “This method can provide detailed information on the surface but without poling depth information.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [304] Li, 2017, Opt. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Thin-film nonlinear wavelength converter and down-conversion sources have shown orders of magnitude higher efficiencies than that using diffusion-based waveguides.

    “Thin-film nonlinear wavelength converter and down-conversion sources have shown orders of magnitude higher efficiencies than that using diffusion-based waveguides.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    CPM-based spontaneous parametric down conversion has been reported in a X-cut LN microdisk resonator.

    “CPM-based spontaneous parametric down conversion has been reported in a X-cut LN microdisk resonator[159].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [159] Hao, 2017, Photon. Res. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    LNOI has a transparency window and ultralow linear loss, and offers EO modulators with performances (>100 GHz, few-volt half-wave voltage, <0.5 dB on-chip insertion loss, and ~100 dB Hz^2/3 SFDR) that few other material platforms can compete with.

    “It not only has transparency window and ultralow linear loss, but also offers EO modulators with performances (> 100 GHz, few-volt half-wave voltage, < 0.5 dB on-chip insertion loss, and ~ 100 dB Hz 2/3 SFDR) that to date few other material platforms can compete with.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    LNOI offers broadband frequency comb sources for multiband operation, and magnetic-free isolators to facilitate integration of on-chip lasers.

    “In addition, it offers broadband frequency comb sources for multiband operation, and magnetic-free isolators to facilitate integration of on-chip lasers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In a photonic molecule, hybrid modes are formed by a pair of evanescently coupled microring resonators.

    “The concept of the photonic molecule, where hybrid modes are formed by a pair of evanescently coupled microring resonators.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [176] McKenna, 2020, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    A CPM-based process generally suffers from a lower conversion efficiency as compared to a QPM-based one given the same resonance condition.

    “A CPM-based process generally suffers from a lower conversion efficiency as compared to a QPM-based one given the same resonance condition.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Thin-film LN has already demonstrated ability to perform heterogeneous integration as well as monolithic wafer-scale processing.

    “as well as the already demonstrated ability to perform heterogeneous integration as well as monolithic wafer-scale processing”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Thin-film LN integrated photonics is rapidly revolutionizing a broad range of applications, from traditional uses in telecommunications and nonlinear optics to emerging fields such as quantum photonics, cavity electro-optics, and piezo-optomechanics.

    “Overall, thin-film LN integrated photonics, building on half-century legacy of discrete components realized in LN crystals, is rapidly revolutionizing a broad range of applications, from its traditional uses in telecommunications and nonlinear optics, to emerging fields such as quantum photonics, cavity electro-optics, and piezo-optomechanics.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    Integration with superconducting detectors, quantum-dot single-photon emitters, and rare-earth ions are promising fully integrated quantum processors.

    “Furthermore, integration with superconducting detectors, quantum-dot single-photon emitters, and rare-earth ions are promising fully integrated quantum processors.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Within the past few years, thin-film LN modulators have significantly outperformed their widely used bulk counterparts in power consumption, bandwidth, and size.

    “Within the past few years, thin-film LN modulators have significantly outperformed their widely used bulk counterparts in power consumption, bandwidth, and size, which are key metrics for next generation optical communication systems.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    LN is neither the smallest nor possessing the highest EO efficiency, but its well-balanced material properties and adequate integrability with decades of industry proven operation could result in rapid deployment.

    “Among many promising new material platforms, such as polymer, plasmonic or barium titanate, while LN is neither the smallest nor possessing the highest EO efficiency, its well-balanced material properties and adequate integrability with decades of industry proven operation could results in rapid deployment.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    LN is not compatible with current CMOS or silicon photonics processes due to material contamination issues, mainly caused by lithium diffusion or residues from the etching process.

    “Unfortunately, LN is not compatible with current CMOS or silicon photonics processes due to material contamination issues, mainly caused by lithium diffusion or residues from the etching process.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Investment and involvement from industry and national facilities are pushing integrated thin-film LN photonics from laboratory proof-of-concept demonstrations to high-yield, wafer-scale productions.

    “Moreover, investment and involvement from industry and national facilities are pushing integrated thin-film LN photonics from laboratory proof-of-concept demonstrations to high-yield, wafer-scale productions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationreasoning

    Such potential in volume applications is key to catalyze LN technology development and could enable scaling up and cost reduction for LN thin-film platform at the foundry-level.

    “Such potential in volume applications is key to catalyze LN technology development and could enable scaling up and cost reduction for LN thin-film platform at the foundry-level.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    The LN platform lacks native light sources, amplifiers, and detectors.

    “However, the LN platform lacks native light sources, amplifiers, and detectors.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Silicon photonics is compatible with CMOS fabrication techniques, which enable large-scale and low-cost production of integrated photonic components at high volumes.

    “Among the key advantages of silicon photonics is the compatibility with CMOS fabrication techniques, which enable large-scale and low-cost production of integrated photonic components at high volumes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The non-reciprocal process of acousto-optic modulation has been demonstrated in AlN and Si, and can be readily adapted to integrated LN systems.

    “This non-reciprocal process of acousto-optic modulation has been demonstrated in AlN [492] and Si [493], and can be readily adapted to integrated LN systems.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [492] Sohn, 2018, Nat. Photonics source

      Not checked in the free run.

    • cites [493] Kittlaus, 2018, Nat. Photonics source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Different frequency modes are coupled by EO modulation and form a tight-binding lattice.

    “Different frequency modes are coupled by EO modulation and form a tight-binding lattice.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [271] Yuan, 2016, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    To realize a fully integrated microwave photonic transceiver, heterogeneous integration of III-V photonic components is a promising direction.

    “To realize a fully integrated microwave photonic transceiver, heterogeneously integration III-V (e.g., InP and InGaAs) photonic components is a promising direction (see Section 6.5).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    It is possible to construct an effective magnetic field using a pair of such modulators driven by microwave fields with different phases, which could lead to optical isolation.

    “Using this property, it is possible to construct an effective magnetic field using a pair of such modulators driven by microwave fields with different phases [285], which could lead to optical isolation as well.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [285] Minkov, 2016, Optica source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Several works have demonstrated the coupling of quantum dot emitters to integrated on-chip silicon-based photonic platforms.

    “Recently, several works have demonstrated the coupling of quantum dot emitters to integrated on-chip silicon-based photonic platforms[431][432][433].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [431][432][433]

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisenone given

    The probabilistic nature of heralded single-photon sources poses significant challenges for scaling up.

    “their probabilistic nature poses significant challenges for scaling up.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The main drawback of silicon based optical materials is the absence of an effective mechanism for cryogenic compatible EO modulation (both phase and amplitude) in these materials.

    “The main drawback of silicon based optical materials is the absence of an effective mechanism for cryogenic compatible EO modulation (both phase and amplitude) in these materials.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Solid-state quantum emitters and quantum dots in 2D materials are excellent sources of on-demand single photons due to their small spatial footprint and good emission properties.

    “Solid-state quantum emitters and quantum dots in 2D materials are excellent sources of ondemand single photons due to their small spatial footprint and good emission properties.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The carrier-envelope offset frequency (f_CEO) can be stabilized by using a self-referencing technique based on f-2f interferometry which requires the generation of a coherent, octave-spanning spectrum.

    “The carrier-envelope offset frequency (f CEO ) can be stabilized by using a self-referencing technique based on f-2f interferometry which requires the generation of a coherent, octavespanning spectrum [372-374].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [372] Okawachi, 2018, Opt. Lett. source

      Not checked in the free run.

    • cites [373] Hickstein, 2019, Nat. Photonics source

      Not checked in the free run.

    • cites [374] Lu, 2019, Opt. Lett. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Heralded single-photon sources can be produced through SPDC processes.

    “While heralded single-photon sources can be produced through SPDC processes”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    On-chip supercontinuum technology has become mature.

    “While the on-chip supercontinuum technology has become mature”
    Quote in the paperNot a substantial claim
253 of 253

  • The authors state this as an assumption.

    Both the source and load (termination) have impedance ZL (in most cases at 50 Ω).

    “Here, we assume both the source and load (termination) have impedance 𝑍𝑍 𝐿𝐿 (in most cases at 50 Ω).”

  • The paper relies on this without support.

    For many applications in high-density integrated photonics, more compact modulators are required.

    “For many applications in highdensity integrated photonics, more compact modulators are required.”

  • The paper relies on this without support.

    Dielectric relaxation effects have yet to be studied directly in LNOI devices.

    “To our knowledge, these effects have yet to be studied directly in LNOI devices, but recent works have observed bias drift consistent with dielectric relaxation [467].”

  • The paper relies on this without support.

    The role of Raman and the dynamics of counterpropagating EO fields remains largely unstudied.

    “The role of Raman and the dynamics of counterpropagating EO fields remains largely unstudied, and the thin-film LN platform presents a promising avenue for exploring more complex nonlinear dynamics.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • LNOI combines high integration density with unique functionalities of electro-optical modulation and second order nonlinearity.

    “Anew promising material for the implementation of future quantum circuits is lithium niobate on insulator (LNOI) since it combines a high integration density, as known from silicon photonics, with its unique functionalities of electro-optical modulation and a second order nonlinearity [5].”

    From Demonstration of Hong-Ou-Mandel interference in an LNOI directional coupler (2023) · cites this paper as [5]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Metasurface-assisted SHG efficiency disagrees with Table 5

    Major

    The text reports a normalized conversion efficiency of 1,660% W−1 cm−2 for the metasurface-assisted device, while Table 5 lists 0.4%/W cm2 for the same reference [320]. These values differ by a factor of 4,150.

  • Table 6 disagrees with the stated SHG efficiency for reference [169]

    Major

    The text gives 0.09%/mW, equivalent to 90%/W, whereas Table 6 lists 0.9%/W for the same ring-shaped resonator reference. The listed values differ by a factor of 100.

  • Simulated propagation exceeds the stated waveguide length

    Minor

    The waveguide used for the Figure 32 simulation is described as 0.5 cm long, yet the discussion says a dispersive wave is generated after propagation beyond 4 cm.

  • SiNx-loaded modulator's VπL differs between prose and Table 3

    Minor

    For reference [203], the prose reports 2.1 V-cm, while Table 3 lists 1.925 V-cm. The table's own voltage and length, 0.875 V and 24 mm, give 2.1 V-cm, supporting the prose value.

  • Figure 6 reverses the Si and TiO2 reference labels

    Minor

    The waveguide discussion assigns reference [96] to TiO2 loading and [97] to Si loading, but the Figure 6 caption assigns those references to Si and TiO2, respectively.

5 of 5

Cites

Flagged first, then by citations

5 of the 530 references couldn’t be matched to a known paper.

Research works printed but not linked: 8

  1. Hu, 2009, Large area, crystal-bonded LiNbO3 thin films and ridge waveguides of high refractive index contrast
  2. Jin, 2016, IEEE Photon. Technol. Lett., 28, 736, 10.1109/lpt.2015.2507136 · DOI
  3. Boyd, 2019, Nonlinear Optics
  4. Stenger, 2017, Low loss and low Vpi thin film lithium niobate on quartz electro-optic modulators, 1
  5. Tsang, 2011, Phys. Rev. A, 84, 043845, 10.1103/physreva.84.04384 · DOI
  6. Boyd, 2008, Nonlinear Optics
  7. Gui, 2010, Periodically Poled Ridge Waveguides and Photonic Wires in LiNbO for Efficient Nonlinear Interactions
  8. Günter, 2005, Photorefractive Materials and Their Applications 1: Basic Effects

Cited by

Sorted by citations

Related

Authors
Zhu, D., Shao, L., Yu, M., Cheng, R., Desiatov, B., Xin, C. J., Hu, Y., Holzgrafe, J., Ghosh, S., Shams-Ansari, A., Puma, E., Sinclair, N., Reimer, C., Zhang, M., & Lončar, M.
Affiliations
  • Harvard University (US)
  • Harvard University
  • California Institute of Technology (US)
Corresponding author
Lončar, Marko
ORCID
Venue
Advances in Optics and Photonics
Publisher
Optica Publishing Group
Published
2021-05-03
Volume
13
Issue
2
Pages
242
ISSN
1943-8206 (ISSN-L)
DOI
10.1364/aop.411024
OpenAlex
W3130725666
Semantic Scholar
2019ed75223f51bf7321f877eefee8bcbf953387
Cited by
1,516
References
530
Citations by year
2026: 293 · 2025: 393 · 2024: 328 · 2023: 271 · 2022: 170 · 2021: 60
FWCI
90.07
Type
journal article
Language
en
Open access
Licence
Locations
  • Advances in Optics and Photonics (publishedVersion, cc-by)
  • arXiv (Cornell University) (submittedVersion)
  • CaltechAUTHORS (California Institute of Technology) (submittedVersion, cc-by)
  • Figshare (submittedVersion, cc-by)
  • OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (submittedVersion)
  • arXiv (Cornell University)
Funders
  • National Science Foundation
  • Harvard Quantum Initiative
  • Natural Sciences and Engineering Research Council of Canada
  • Office of Naval Research
  • Air Force Office of Scientific Research
  • Defense Advanced Research Projects Agency
  • U.S. Department of Energy
  • Army Research Laboratory
  • Army Research Office
  • Raytheon Company
  • Nokia Bell labs
  • Rockwell Collins
  • Google
  • Alliance for Quantum Technologies, California Institute of Technology (INQNET)
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Photorefractive and Nonlinear Optics
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Photonic and Optical Devices
  • Physical Sciences › Engineering › Biomedical Engineering › Acoustic Wave Resonator Technologies
Keywords
lithium niobate, thin-film lithium niobate, integrated photonics, lithium niobate on insulator, optical modulators, nonlinear frequency conversion, electro-optic devices, acousto-optic devices, low-loss resonators, optical frequency combs, quantum transducers, wafer-scale thin films

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-07.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-07.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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