Performance-enhanced silicon thermo-optic Mach-Zehnder switch using laterally supported suspended phase arms and efficient electrodes.

We report a silicon thermo-optic Mach-Zehnder switch with a broadband, low switching power, and fast response. A broadband 3 dB directional coupler is used to act as a power splitter. Laterally supported suspended phase arms are employed to substantially reduce the switching power without sacrificing too much on the temporal response. Furthermore, two metallization steps are utilized to further decrease the power consumption. We experimentally obtain a switching power as low as 1.1 mW, as well as a fast response of 76 and 48 μs for rise time and fall time, respectively. The demonstrated device also has a relatively high mechanical strength and compact size, making it promising to be applied in silicon photonic integrated circuits.