A dual polarization optical 90°-hybrid in silicon-on-insulator waveguides

Abstract

An all-passive dual polarization optical 90°-hybrid in silicon-on-insulator waveguides is proposed and designed. It consists of two 2x2 MMI-MZI structures, working as polarization beam splitters, and two 4x4 MMI couplers, working as 90°-hybrids. The fabrication process includes only one step of inductively coupled plasma (ICP) etching. It is particularly suitable for silicon-based integration of DP-QPSK receiver.