Low-loss and low-crosstalk hybrid WDM-PDM (de)multiplexer based on a microring-resonator array

A high-performance hybrid multiplexer for wavelength division multiplexing (WDM) and polarization-division multiplexing (PDM) is proposed and realized by combining a polarization-splitter-rotator (PSR) and a microring resonator (MRR) array. A 16-channel hybrid multiplexer with eight wavelength-channels and dual polarizations is demonstrated as an example. Any MRR works bi-directionally and provides two drop ports. The MRR array enables a box-like response for WDM filtering with a channel spacing of 400 GHz. The 3dB-bandwidth is as large as 2nm and the channel crosstalk is less than −25dB. The on-chip loss for the present 16-channel hybrid (de)multiplexer is ∼3dB only.