Polarization-Insensitive Directional Couplers Based on SOI Wire Waveguides

Abstract

Optical directional couplers based on SOI-wire waveguides have been modelled by a semi-analytical approach based on the Coupled Mode Theory and Finite Element Method. The modelling is used to obtain analytically optical power at the parallel and cross ports by utilizing numerically calculated coupling coefficients. Geometrical dimensions of the couplers have been optimized to obtain a polarization-independent behaviour. The influence of non-vertical sidewalls on the coupler performance has also been addressed.