Silicon-Based Integrated Comb Filter and Demultiplexer for Simultaneous WDM Signal Processing

We design and fabricate a silicon-based integrated comb filter and arrayed waveguide grating (AWG), which can perform the multichannel filtering and wavelength demultiplexing in the wavelength division multiplexing (WDM) system. The comb filter with specific free spectra range performs the simultaneous filtering, and the AWG achieves the wavelength demultiplexing function. With the proposed device, parallel multichannel signal processing can be achieved based on the linear passive filtering. Furthermore, assisting by a nonlinear device, some nonlinear signal processing functions can also be achieved. For demonstration, the format conversions for WDM return-to-zero (RZ) to nonreturn-to-zero (NRZ), the demodulation for the differential phase-shift keying signals, as well as the NRZ-to-RZ conversions assisting by a semiconductor optical amplifier are experimentally demonstrated successfully. The experimental results show the good performances and the practicability for the proposed device.