Cost-Effective $2\times 2$ Silicon Nitride Mach-Zehnder Interferometric (MZI) Thermo-Optic Switch

We present cost effective $2 \times 2$ silicon nitride Mach-Zehnder interferometric thermo-optic switches with 1 mm-length phase shifter. Devices were fabricated on a bulk silicon wafer with CMOS compatible process. The footprint was ~0.7 mm2. For the device designed for $\lambda \!\!\sim 1310$ nm, we demonstrated ~26.8-dB crosstalk, 0.23-dB insertion loss, and 17.25- $\mu \text{s}$ switching speed at $\lambda \!\!\sim 1325.8$ nm. Similarly, $\lambda \!\!\sim 1550$ nm device showed the ~24.7-dB crosstalk, 0.48-dB insertion loss, and 17.48- $\mu \text{s}$ switching speed at $\lambda \!\!\sim 1550.8$ nm. The measured operating power was 55.6 and 64.4 mW at $\lambda \!\!\sim 1325.8$ nm and $\lambda \!\!\sim $ 1550.8 nm, respectively.