| 摘要 |
PURPOSE:To enable local control in formation of an optical waveguide while maintaining the uniformity of the waveguide and decreasing optical transmission loss by depositing a layer for protecting LiNbO3 againt a thermal diffusion treatment around the surface area for forming the optical waveguide and diffusing thermally the metalic layer into a crystal plate. CONSTITUTION:The surface of an LiNbO3 plate is covered thereon with a resist pattern 22 except the area for forming an optical waveguide. An H ion is then implanted thereon to form a damaged region 21' in the plate 21. After the removal of the pattern 22, a metallic Ti layer 23 is deposited by evaporation over the entire surface of the plate 21. Ti is then diffused over the entire part of the plate 21. The coefft. of Ti diffusion increases in the region 21' and an optical waveguide 21'' is formed. The disturbance in the formation of the waveguide 21'' owing to the escape of Li from LiNbO3 during the diffusion treatment of the waveguide 21' is thus obviated and since the Ti is diffused in the preformed region 21', the time fot the treatment is reduced. If the distribution of the implanted damages is made uniform by combining plural kinds of the elements to be ion-implanted, the local control of the waveguide 21'' is possible. |
