High extinction ratio and broadband silicon TE-pass polarizer using subwavelength grating index engineering

摘要

We propose and experimentally demonstrate a novel approach to implement a low loss, broadband and compact transverse electric (TE)-pass polarizer on a silicon-on-insulator (SOI) platform. The TE-polarizer utilizes a subwavelength grating (SWG) structure to engineer the waveguide equivalent material index. In this work, the SWG-based polarizer only supports its fundamental TE mode while the transverse magnetic (TM) mode is suppressed under the cut-off condition, i.e., the TM mode leaks from the waveguide with a low reflection. The simulations predict that the bandwidth to achieve a polarization extinction ratio (ER) of 35 dB exceeds 200 nm. Experimentally, the measured polarization ER is ~30 dB and the average insertion loss is 0.4 dB, in the wavelength range 1470 nm - 1580 nm. The fabricated TE-polarizer has a compact length of 60 \u3bcm.