A silicon mode multiplexer based on the three-stage cascaded wavelength insensitive coupler for MDM-WDM transmission system

Abstract

A silicon mode multiplexer (MUX) based on the three-stage cascaded wavelength insensitive coupler (3CWINC) is proposed and numerically demonstrated. The 3CWINC is composed of three identical asymmetric directional couplers (ADCs) and two different phase adjustment regions placed between each ADC. We numerically show that high-performance mode MUX is easily designed using 3CWINC, which consists of ADC with transmission higher than 25% over the entire operating wavelength range. The designed TE₀-TE₁ mode MUX based on 3CWINC can maintain transmission 94.4% (−0.25 dB) or higher even if fabrication error of waveguide width occurs up to 10 nm.