Effects of a buffer layer on TM modes in a metal-clad optical waveguide using Ti-diffused LiNbO(3) C-plate.

The effects of a buffer layer on the TM modes in a Ti-diffused LiNbO(3)C plate optical waveguide with metal cladding are described by examining the transverse load impedance. The loss reduction, the absorption peak, and the mode transformation of the TM modes in the metal-clad diffused waveguide with respect to the thickness of a SiO(2) buffer film are clarified by the numerical solutions of the dispersion equations. The Ti-diffused region of the waveguide is assumed to be well represented by a region with a permittivity that decreases linearly away from the waveguide surface.