| 摘要 |
PURPOSE:To reduce the loss of coupling with an optical fiber by forming a waveguide which has a larger diameter than a waveguide seed and recrystallizing a part of a substrate which becomes uncrystallized. CONSTITUTION:A dope element is injected by a converged ion beam method into nearby the surface of the substrate 41 to form the waveguide seed 42. Then the substrate 41 is heated to diffuse the injected dope element thermally and thus form the waveguide 43 having the larger diameter than the waveguide seed 42, and the part 44 of the substrate 41 which becomes uncrystallized by the injection is recrystallized. A thin film 44 is formed of a material homogeneous with the substrate 41 on the surface of the substrate 41 and then the waveguide 43 with a relatively high refractive index is surrounded with the substrate 41 and thin film 44 which have a low refractive index. Consequently, the optical waveguide 43 which has small loss in coupling with the optical fiber is obtained. |
