A Compact Silicon Photonic DQPSK Receiver Based on Microring Filters

An extremely compact integrated receiver for differential quadrature phase shift keying signals based on two tunable silicon-on-insulator microring resonators and four integrated germanium photodetectors is reported. Simulations show the expected performance of the device and how it compares with alternative receivers, i.e., conventional receivers based on delayed Mach-Zehnder interferometers and Gaussian filters-based ones. The device, fabricated in a silicon photonic multiuser wafer run, is described and experimentally characterized showing operation for signal ranging from 10 to 20 Gbaud.