Fabrication of a 4 × 4 strictly nonblocking SOI switch matrix

A 4 × 4 strictly nonblocking thermo-optical switch matrix based on Mach-Zehnder (MZ) switching unit was designed and fabricated in silicon-on-insulator (SOI) wafer. The paired multi-mode interferometers (MMI) were used as power splitters and combiners in MZ structures. The device presents an average insertion loss of 17 dB and an average crosstalk of 16.5 dB. The power consumption needed for operation is reduced to 0.288 W by adding isolating trenches. The switching time of the device is about 15 μs, which is much faster than that of silica-based switches.