Tellurite glass microcavity resonators integrated on a silicon photonics platform

Abstract

Abstract. We report on the design and measurement of tellurium oxide microcavity resonators coupled to silicon bus waveguides on silicon photonic chips. The resonators are fabricated using a standard silicon photonics foundry processing flow in which the SiO2 top-cladding is etched in a ring shape and aligned next to a silicon bus waveguide. The resulting microtrench is coated in a tellurium oxide film by reactive sputtering in a post-processing step to form the waveguiding layer of the resonator. A 100-μm radius trench with a 1115-nm-thick TeO2 film is measured to have an internal Q factor of 0.9  ×  105. Smoothing the etch wall surface with a fluoropolymer coating is shown to enhance the Q factor of several devices, with a trench coated in a 630-nm-thick TeO2 film demonstrating a Q factor of 2.1  ×  105 corresponding to 1.7-dB/cm waveguide loss. These results demonstrate a potential pathway toward monolithic integration of tellurite glass-based nonlinear and rare-earth-doped devices compatible with silicon photonics platforms.