1 × N All-Logic Optical Switch Based on Polymer Platform Using Multimode Interferometer

Abstract

The compact and broadband optical switch with a large port count is demanded with the increasing communication capacity. In this article, a universal method for modeling the 1 × N switch using multimode interferometer (MMI) through transmission matrixes is proposed. Herein, the reasons for the narrowing of the operating bandwidth switch are analyzed. As a proof of concept, a wide bandwidth 1 × 4 switch, which has an insertion loss lower than 23.7 dB, and a cross talk better than −10 dB at 1550 nm are simulated, designed, and fabricated. The cross talk throughout the C band is lower than −8.5 dB. According to the experimental result, the 1 × 4 switch with four-equal-length modulating arms shows a 32 nm bandwidth for −10 dB cross talk which is 13 times larger than traditional switch. The switch realizes a multi-port logic optical switch by modulation. The 1 × N switch based on the generalized Mach–Zehnder interferometer (GMZI) structure reduce the footprint significantly compared with the 1 × N switch consisting of a 1 × 2 switch cascade. It is believed that 1 × N switch based on GMZI structures is a promising solution to increase integration density.