A Low Crosstalk and Broadband Polarization Rotator and Splitter Based on Adiabatic Couplers

A low crosstalk and broadband polarization rotator and splitter (PRS) consisting of a bi-level adiabatic taper, a symmetric micro Y-junction and adiabatic couplers is proposed and demonstrated using a silicon-on-insulator platform. Due to the principle of mode evolution, the proposed PRS exhibits superior performance over a broad bandwidth. The waveguide with a thin ridge layer is introduced to reduce the crosstalk from TM ₀ mode and increase the coupling strength of TE ₀ mode. The proposed PRS is experimentally demonstrated with a loss about 1 dB and a crosstalk about -14 dB over a wavelength range of 100 nm.