| 摘要 |
PURPOSE:To impress a strong modulation electric field on a place where light intensity is high by providing a groove along an optical waveguide on the surface of an insulating buffer layer in the vicinity of the optical waveguide and providing a projection complementary to the groove on an electrode which comes into contact with the groove between two electrodes. CONSTITUTION:The optical waveguide 2 is formed on a part of an LiNbO3 substrate 1. Two electrodes 4 and 4' being substantially in parallel, which are arranged along the optical waveguide 2 and impress high frequency electric field on the optical waveguide 2, and the insulating buffer layer 3 provided between the respective electrodes 4 and 4' and the optical waveguide 2 are installed. In such a case, the groove 7 is provided along the optical waveguide 2 on the surface of the insulating buffer layer 3 in the vicinity of the optical waveguide 2, and the projection complementary to the groove 7 is provided on the electrode 4. Namely, since the electrode 4 is protruded toward the optical waveguide 2 side, the electric field is concentrated on the optical waveguide 2. Thus, the modulation efficiency is enhanced and driving voltage is dropped. |
