We report on compact and efficient silicon-organic hybrid (SOH) Mach-Zehnder modulators (MZM) with low phase-shifter insertion loss of 0.7 dB. The 280 µm-long phase shifters feature a π -voltage-length product of 0.41 Vmm and a loss-efficiency product as small as aU π L = 1.0 VdB. The device perf…