Vector beam propagation analysis of polarization conversion in periodically loaded waveguides

An improved design of a short and low-loss polarization converter is proposed. It consists of an asymmetrically periodic loaded rib waveguides. At a wavelength of 1.5 μm, 98% polarization conversion ratio is obtained with a relatively short 0.74-mm device length and an extremely low 0.13-dB total insertion loss. The simulation results are obtained using a full vector beam propagation method based on the finite element method.