Scattering of optical surface waves by a covered groove

Abstract

The reflectionjand modeconversionbehavior is considered for both TE(0) and TM(0) modes at a covered groove, which is cut in the substrate surface and covered by a thin film. With a numerical example, the scattering behavior of covered and surface grooves is presented here. It is found that a covered groove produces much less radiation loss than a surface groove of the same shape. Therefore, it is preferable as a reflector element in applications which require minimum mode conversion loss. On the other hand, surface grooves are preferable for grating couplers as they provide stronger coupling from surface to space waves as observed in this study.