Fabrication of high-Q multimode microring resonators on a photonic silicon-on-insulator platform

This work reports on the fabrication and optimization of silicon microring resonators on SOI platforms with a focus on rapid device prototyping. Such resonators are instrumental in expanding the functionality of photonic circuits, be it by leveraging the inherent nonlinearities of silicon or by improving frequency filtering. Central to this investigation is the detailed fabrication techniques developed for SOI waveguides, specifically tailored to minimize losses. Devices are created using Electron Beam Lithography and are etched using Reactive Ion Etching. The performance of microrings with single-mode waveguides is compared with that of multimode variants, and it is shown that the latter mitigate the impact of sidewall roughness, thereby reducing scattering losses. Through optimization of the patterning parameters, etching recipes and thermal treatment, developed devices exhibit propagation losses as low as 0.28 dB/cm and Q factors in the vicinity of 2x10(5).