Polarization-insensitive low-voltage optical waveguide switch using InGaAsP/lnP four- port Mach-Zehnder interferometer

Abstract

Polarization-independent operation is highly desirable for optical-waveguide switches. It can be realized with directional couplers, digital optical switches (DOS’s),1 and Mach-Zehnder interferometric (MZI) devices. MZI switches2 have spatially separated regions for electro-optic phase shifting and mode coupling that may permit independent optimization. Multimode- interference (MMI) couplers were recently demonstrated to be promising as polarization-insensitive and fabrication-tolerant power splitter-combiners.3 Zucker et al.4 realized a polarization- insensitive MZI switch by applying MMI couplers and introducing strain in quantum wells.