Low-loss broadband 5 × 5 non-blocking Si3N4 optical switch matrix

Abstract

An integrated 5×5 non-blocking optical switch matrix is proposed and experimentally demonstrated based on the silicon nitride (Si3N4) platform. The proposed optical switch matrix is designed with the Spanke–Benes architecture having 10 balanced Mach–Zehnder interferometers, each of which operates as a 2×2 switching unit enabled by an on-chip thermo-optic phase shifter. Over an 80 nm bandwidth (from 1520 to 1600 nm), the optical switch matrix is characterized with intriguing specifications, including the average extinction ratio larger than 25 dB, the excess loss less than 5 dB for both “all-cross” and “all-bar” states, and the leaked power lower than −48 dB. To the best of our knowledge, this is the first non-blocking optical switch matrix based on a Si3N4 platform with leading comprehensive performance in extinction ratio, excess loss, leaked power, and bandwidth. It will provide enabling building blocks for massive switch networks of optical communications and microwave photonics.