Low loss, wideband, and high extinction ratio TM polarizer based on subwavelength gratings

Abstract

We propose a low loss, wideband silicon transverse magnetic (TM) polarizer with high polarization extinction ratio and low reflection based on subwavelength grating. By arranging and optimizing a mutually perpendicular subwavelength grating with different duty cycles as the core and cladding, efficient waveguiding and radiation can be achieved for the TM and transverse electric (TE) injection, respectively. In simulation, the proposed TM polarizer has a footprint of 40µm×16.68µm, an insertion loss <0.7dB, a polarization extinction ratio ≥20dB, and an unwanted TE reflection <−17.4dB in the wavelength range of 1230–1700 nm. Moreover, the fabrication tolerance of the proposed device is also investigated.