20-Gb/s Silicon Optical Modulators for the 2 μm Wavelength Band

We demonstrate silicon-on-insulator based high speed modulators working at a wavelength of 1950 nm. The carrier-depletion Mach-Zehnder interferometer modulator operates at a data rate of 20 Gbit/s with an extinction ratio of 5.8 dB and modulation efficiency (V _π L _π ) of 2.68 Vcm at 4 V reverse bias.