Polarization-Insensitive Thermo-Optic Mach Zehnder Device Based on Silicon Oxinitride Waveguide with Fast Response Time

In this article, a thermo-optic structure with a silicon trench below the heater and stress-releasing grooves in both sides of the core is proposed for a thermo-optic Mach Zehnder switch using silicon oxinitride as a core and SiO2 as a cladding. It is seen from thermal analysis by using the implicit finite difference method that the absolute value of the temperature gradient of the proposed structure, which mainly causes the release of stress anisotropy, is approximately nine times more than that of a conventional structure. The response time of the thermo-optic Mach Zehnder device, based on the proposed structure with a switching power of ∼177 mW is estimated as 180 μs, which is about 100 times faster than that of the existing structure.