4 × 4 nonblocking optical switch fabric based on cascaded multimode interferomet

We experimentally demonstrate a 4 × 4 nonblocking silicon thermo-optic (TO) switch fabric consisting of three stages of tunable generalized Mach–Zehnder interferometers. All 24 routing states for nonblocking switching are characterized. The device’s footprint is 4.6 mm × 1.0 mm. Measurements show th