Polarization manipulation devices based on silicon photonic wire waveguides and their practical application

A compact polarization splitter and rotator based on silicon photonic wire waveguide have been developed. The splitter is based on simple directional couplers. In the fabricated splitter, the polarization extinction ratio is 23 dB and excess loss is less than 0.5 dB. The rotator consists of a silicon waveguide and an off-axis silicon oxinitride waveguide. In the fabricated rotator, efficient polarization rotation was observed, and the excess loss is about 1 dB. Using these devices, a polarization diversity system for ring-resonator wavelength filters has also been developed. The polarization dependent loss of the filter with diversity is about 1 dB.