Radiation from an annular grating on a planar optical waveguide

Abstract

This letter discusses the radiation scattering properties of a concentric-circle grating on the surface of an optical waveguide. A boundary perturbation method is used to obtain an analytical expression for the field radiated by a set of concentric rings located at the film–cover interface of the waveguide. The analytical expression for the radiation field consists of a scattering integral which is integrated to predict the field’s intensity at points in the far field.