| 摘要 |
PURPOSE:To obtain a waveguide in which light is strongly confined by forming a nitride film on the surface of LiNbO3 to prevent exposing of the crystal surface and to suppress external diffusion of Li. CONSTITUTION:The nitride film 2 is formed on the surface of the LiNbO3 substrate 1 and a guide pattern is formed thereon by a resist 3. The nitride film in the guide part is removed by etching with said pattern as a mask. Ti is deposited by evaporation thereon and is lifted off to remove the resist 3 and the Ti film 4 on the resist so that the Ti film 4 remains only on the guide part on the substrate 1. The substrate formed with the Ti film 4 only in the guide part is charged into a thermal diffusion furnace and is thermally diffused to form the waveguide. Since the crystal surface except in the part where the waveguide is formed is covered by the nitride film 2, the external diffusion of the Li is prevented. The light guide which confines the light excellently is thereby obtd. |
