Emission of E and H waves from a corrugated section of a diffused waveguide

An investigation is reported of the emission of a surface optical wave (of the E or H polarization) from a corrugated section of a diffused waveguide. The propagation of a wave in such a waveguide differs from the corresponding propagation in a thin-film waveguide because there is no sharp boundary between the waveguide and the substrate. It is shown that there is a corrugation period for which there is no damping of the E waves. An experimental check of this conclusion is reported.