Polarization conversion by reflection in a thin-film grating

A dielectric-film waveguide with a grating etched on its film-cover interfa ce can be used as a polarization converter. The e wave can be converted int o the h wave and vice versa if the guided wave is incident obliquely to the grating vector. The polarization converter is analyzed by use of a quasi-o ptic technique. A high degree of polarization-conversion efficiency is achi eved by a suitable choice of the grating length. The Bragg angles of incide nce and observation, the maximum polarization-conversion efficiency, and th e frequency and the angular selectivity are all found to increase with an i ncrease in the grating period. An illustrative numerical example is present ed. (C) 2001 Optical Society of America.