Low loss silicon nitride based multimode interference beam splitter in a near polarization insensitive regime

Abstract

Design and simulation process for a multimode interference (MMI) device based on a silicon nitride platform presented. The objective is to achieve a low-loss MMI model as a beam splitter at 1550 nm wavelength. Additionally, the device should exhibit least sensitivity to polarization changes. Finite element method employed throughout simulations and optimizations. Following mode analysis and preliminary design, the device optimized by a tapering assisted structure to operate near a polarization insensitive regime (0.062 dB TE and 0.078 dB TM). The impact of wavelength variation and fabrication imperfections on the device’s performance also investigated. The optimized design shows stable performance, making it suitable for wideband communication and quantum optical integrated circuits.