Theoretical approach to a polarization-insensitive single-mode microring resonator

Abstract

This paper addresses the polarization sensitivity issue of micro-ring resonators by proposing a novel design of an MMI-coupled resonator with substantially reduced or zero polarization sensitivity, while maintaining singlemode and low-loss conditions. The design is based on polarization-independent, single-mode waveguide obtained by using a judicious combination of critical ridge width and etch depth. The design is limited to relatively large resonators having small FSR (free spectral range). For the first time, it gives designer a handle on the intrinsic polarization-dependent characteristics of waveguide microresonators.