Silicon Optical Interconnect Device Technologies for 40 Gb/s and Beyond

Important active technologies, modulators, photodetectors, and thermooptics for low-energy silicon optical interconnects are discussed. High-speed performance up to 40 Gb/s is reported for the silicon modulators and germanium photodetectors, and approaches for further improvement in speed and efficiency are presented. Low-voltage avalanche multiplication is demonstrated, giving a gain-bandwidth product of 75 GHz, while the combined effects of multiplication gain and the Franz-Keldysh effect enable a 5-μm-long germanium photodetector to achieve responsivity in the L-band that is comparable to that in the C-band. With trench-based thermal isolation, a low switching power of 0.4 mW is achieved for a thermooptic switch.