| 摘要 |
PURPOSE:To make it possible to perform high speed modulation readily without using external modulation, by imparting a potential to electrodes, thereby yielding difference in refractive indexes of two lightguides, and selectively taking out two light beams, which are oscillated in the two lightguides and have phase difference, into an output lightguide. CONSTITUTION:On the a substrate 1, the following parts are provided: two parallel lightguides 2 and 3, which are optically coupled; a coupling device 4, where the two lightguides 2 and 3 are coupled; an output lightguide 5 connected to the coupling device 4; and electrodes 6 on the surface of the substrate. Two light beams having phase difference are oscillated in the two lightguides 2 and 3, which serve the roles of laser units. When a potential is imparted to the electrodes 6, the difference in refractive indexes is yielded between the two lightguides 2 and 3. Then either of the two light beams is selectively taken out by said optical switching action and put into the output lightguide 5. The light is emitted to the outside of the substrate 1. In order to make large-capacity transmission possible in this way, phase modulation characterized by excellent high-speed property and transmission efficiency of the optical switch utilizing the electroptical effect is used. |
