Broadband and CMOS compatible polarization splitter–rotator based on a bi-level taper

A silicon-on-insulator polarization diversity scheme is proposed. Based on an asymmetrical evanescent coupler, a broadband and compact polarization splitter–rotator comprising mode conversion tapers and mode sorting asymmetric Y junctions is optimized with silicon dioxide upper cladding and a silicon nitride waveguide. The simulation results show mode conversion loss is less than 0.2 dB, and the extinction ratio is lower than − 17 d B in the wavelength range of 1.48 µ m to 1.67 µ m .