Silicon-based on-chip hybrid (de)multiplexers

A review is given on the recent progress of silicon-based on-chip hybrid multiplexers, which are the key elements to enable more than one (de)multiplexing techniques simultaneously, including wavelength-division-multiplexing (WDM), polarization-division-multiplexing (PDM), and mode-division-multiplexing (MDM). This helps enhance the link capacity of optical interconnects multiplexed with many channels. The first part gives a review on the recent developed silicon-based hybrid WDM-PDM (de)multiplexers enabling WDM and PDM simultaneously, which helps achieve 2N channels by introducing N wavelengths and dual polarizations. The recent progress of silicon-based hybrid WDM-MDM (de)multiplexers developed is reviewed in the second part. With the hybrid WDM-MDM (de)multiplexers, one can achieve NxM channels by using N wavelengths and M guided-modes. Finally, the silicon-based hybrid MDM-PDM (de)multiplexers are presented as the key to enhance the link capacity for a single wavelength carrier.