| 摘要 |
PURPOSE:To easily obtain a low-loss waveguide channel having coupling characteristics equivalent to that for single-mode fiber by its production through the first ion exchange process, an electric field-applying annealing process and the second ion exchange process. CONSTITUTION:An ion exchange control film 11 having a specified waveguide channel pattern is first formed on a monovalent ion-contg. glass substrate 10 capable of ion exchange. Second, the resulting substrate 10 is immersed in the first molten salt 2 containing the first monovalent ion, and a thermal ion exchange is made through said film 11 to change the refractive index of the substrate 10. Third, an etching is made to remove part of the control film 11 from the substrate 10. Fourth, at temperatures close to that in the first ion exchange process, an electric field is applied on the substrate 10 to effect annealing with the film 11-adhered side put to positive voltage. Thence, the resulting substrate 10 is immersed in the second molten salt containing the second monovalent ion acting oppositely to the first monovalent ion in terms of the refractive index of the substrate 10 followed by carrying out a thermal ion exchange. |
