| 摘要 |
PURPOSE:To obtain an excellent switching state even if a deviation in coupling length is generated by providing a 3rd electrode which is applied with a variable voltage for biasing on an optical waveguide layer between clad layers. CONSTITUTION:The clad layers 13 and 14 which are arranged in parallel have opposite internal surfaces 13a and 14a and external surfaces 13b and 14b positioned outside them. On an optical waveguide layer 12 on the side of the internal surfaces 13a and 14a, an ohmic electrode (3rd electrode) 18 for biasing is formed. Therefore, the 3rd electrode 18 increases the refractive index of the optical waveguide layer 12 right below the 3rd electrode 18 by being applied with the variable voltage for biasing to increase the electrode field coupling between the clad layers. Further, the variable voltage for biasing is varied to adjust the extent of electric field coupling. Consequently, even if the deviation in coupling length is caused by an error in manufacture, the excellent switching state can be obtained. |
