| 摘要 |
PURPOSE:To improve the modulation efficiency by providing a first electrode through a buffer layer on a three-dimensional optical waveguide which is formed on the upper face of a substrate, and also, providing a second electrode which is formed directly on the surface of the substrate in parallel to an optical waveguide. CONSTITUTION:On a three-dimensional optical waveguide 11 which is formed on the upper face of a substrate 10 consisting of an electro-optical crystal, the first electrode 13 is formed through a buffer layer 12, and also, the second electrode 14 which is formed directly on the surface of the substrate 10 in parallel to the optical wavguide 11 is provided. Accordingly, a capacitance is not constituted between the second electrode 14 and the substrate 10, therefore, in modulation voltages applied between the electrodes 13, 14, the voltage applied to the substrate 10 part contributed to the modulation can be increased. In such a way, the modulation efficiency can be improved. |
