Design of a compact photonic-crystal-based polarizing beam splitter

Abstract

A compact polarizing beam splitter based on a photonic crystal (PC) directional coupler with a triangular lattice of air holes is designed and simulated. In the employed PC structure, transverse-electric (TE) light is confined with the photonic bandgap effect, while transverse-magnetic (TM) light is guided through an index-like effect. Due to the different guiding mechanisms, TM and TE light have strikingly different beat lengths, which is utilized to separate the two polarizations in a directional coupler no longer than 24.2 μm. The two-dimensional finite-difference time-domain method of computation is used to evaluate the device performance. The extinction ratios are found to be around 20 dB for both TE and TM polarized light.