| 摘要 |
PURPOSE:To obtain an optical control element less in the deterioration of the characteristics of electric conductivity even in a high frequency region by forming the thickness of a crystal base plate to a value for interrupting the modes of electromagnetic waves except TEM modes propagating to the electrode. CONSTITUTION:An optical waveguide 10 is formed on a LiNbO3 base plate 1 by a treatment such as Ti diffusion and proton exchange, a signal line 2 is provided along the optical waveguide 10, and a ground electrode 3 is provided along the signal line 2. An SiO2 film 6 is formed as an insulating buffer layer between the base plate 1 and the signal line 2 and between the base plate 1 and the grounding electrode 3. The base plate 1 is fitted to a metal plate 4 such as a casing to electrically connect the ground electrode 3 to the metal plate 4. The metal plate 4 is provided with through holes 5, through which the signal line 2 is connected to an external microwave supply. The thickness (t) of the base plate 1 thiner than a is made value satisfying -0.636.logt+2.982=logf; wherein (f) is frequency of the microwave to be propagated to the signal line 2. |
