Study of the effects of the geometry on the performance of vertically coupled InP microdisk resonators

High-quality-factor vertically coupled InP microdisk resonators have been fabricated. The devices exhibit smooth sidewalls, single-mode operation, high-quality factors Q in excess of 7000, and finesse of 50. The influence of different structural parameters on the device performance is investigated both theoretically and experimentally. These include the disk radius R, the coupling separation d_c, the thickness of the thin membrane between the waveguides and resonator that remains after fabrication t, and the waveguide etch depth d_WG (defined as the distance between the core layer of the waveguides and the thin membrane).