Four-wave mixing in high-Q tellurium-oxide-coated silicon nitride microring resonators

We report the first-time observation, to the best of our knowledge, of four-wave mixing (FWM) in hybrid tellurium oxide coated silicon nitride ring resonators with internal Q factors of 1.7 × 10 5 to 1.0 × 10 6 . We show oscillation at NIR wavelengths ranging from 1020 nm to 2530 nm under 1590 nm pumping. The FWM process has been investigated for TeO 2 -coated Si 3 N 4 ring resonators with a 600 µm radius and FWM is observed for threshold launched pump powers as low as 25 mW with normal group velocity dispersion (GVD). With the potential for engineering of the GVD to the anomalous regime, a phase-matched and more efficient FWM process can be realized, which can pave the way for broadband frequency comb generation in this platform. These results suggest further promise of higher performance and lower threshold power nonlinear devices on a low-loss CMOS compatible platform with the possibility of co-integration of active functionalities due to high solubility of rare earth dopants in tellurium oxide.