Broadband 4×4 non-blocking optical switch fabric based on Mach-Zehnder interferometers

We demonstrate a silicon 4×4 non-blocking Benes switch fabric consisting of three stages of tunable Mach-Zehnder interferometers. Measurements show that the insertion loss is around 10 dB and the crosstalk is below -10 dB over a 40 nm wide wavelength range.