Ultrahigh-Q silicon resonators in a planarized local oxidation of silicon platform.

We describe a platform for the fabrication of smooth waveguides and ultrahigh-quality-factor (Q factor) silicon resonators using a modified local oxidation of silicon (LOCOS) technique. Unlike the conventional LOCOS process, our approach allows the fabrication of nearly planarized structures, supporting a multilayer silicon photonics configuration. Using this approach we demonstrate the fabrication and the characterization of a microdisk resonator with an intrinsic Q factor that is one of the highest Q factors achieved with a compact silicon-on-insulator platform.