| 摘要 |
PURPOSE:To easily manufacture an optical waveguide circuit which has small loss at a Y-branch part by an ion exchanging method by delaying the advance of ion exchange substantially at the branch part where waveguides are close to each other behind that at other areas. CONSTITUTION:For example, when a single waveguide 2a branches into two, the branch part 10 which extends until the branch waveguides separate at a constant interval or more is provided with a 2nd mask film 3 covering the opening part of a 1st mask film 2. In a subsequent ion exchanging process, a material which functions to limit ion transmission to some extent is used for the 2nd mask film 3. Thus, the ion exchange is slowed down relatively at the branch part 10 where the waveguides are close to each other, so an abnormal ion diffusion phenomenon at the branch part 10 is suppressed. Consequently, the branch waveguides which are in nearly the same constant shape with the linear part 10 and have nearly the same constant characteristics are easily obtained by the ion exchanging method and the loss at the branch part 10 is reducible. |
