Patent ID: 7664344

Claim:
A method of fabricating an electro-optic modulator, comprising the steps of: forming an optical waveguide in a substrate, wherein the substrate is made of a material which has an electro-optic effect, and the optical waveguide comprises at least a pair of optical paths; laminating at least one transparent insulator film and at least one transparent conductor film to form laminated films on the substrate and on the optical waveguide; mutually diffusing the laminated films into each other to form a buffer layer on the substrate and on the optical waveguide, wherein the buffer layer is transparent, wherein the laminated films are mutually partially diffused into each other, and wherein the buffer layer has a structure in which there is no clear boundary between the at least one transparent insulator film and the at least one transparent conductor film; and forming electrodes on the buffer layer, wherein the electrodes are arranged to cause refractive index changes in the pair of optical paths in response to electrical fields surrounding the electro-optic modulator.