Fully polarisation independent Mach-Zehnder optical switch using a lattice-matched InGaAlAs/InAlAs MQW and high-mesa waveguide structure

Abstract

Using a semiconductor Mach-Zehnder optical switch, the authors have succeeded in obtaining polarisation-independent operation with respect to switching voltage and insertion loss. A polarisation-independent phase shift can be obtained by using a lattice-matched InGaAlAs/InAlAs MQW structure. To reduce the insertion loss difference between polarisations, the authors used a multimode-interferometer 3 dB coupler and a high-mesa waveguide structure in the switch.