Symbol-rate-variable DQPSK receiver fabricated using CMOS-compatible process

We demonstrate a silicon DQPSK receiver, that is symbol-rate variable, fabricated by using CMOS-compatible process. It consists of Si-wire waveguides, splitters/couplers, heater-controlled Mach-Zehnder attenuators, phase shifters, 90° hybrid including low-loss crossing and balanced Ge photodetectors. In addition, micro-ring-based slow-light device is introduced to demodulate various bit-rate signals. The demodulation was observed at bit-rates of 14.8 - 18.0 Gb/s.