| 摘要 |
PURPOSE:To perform control by an easy digital logic circuit by dividing electrodes of an optical branching device into plural parts on an optical waveguide and selecting electrodes to be applied with a voltage among them according to a branching ratio. CONSTITUTION:The electrodes to be applied with the voltage consist of plural sectioned electrodes 41-48 and one or specific electrodes are selected among the electrodes 41-48 and applied with the constant voltage to vary the branching power ratio of light branching between both optical waveguides 21 and 22. In this case, the branching ratio can be varied by varying the length of an optical waveguide part applied with the voltage. For the purpose, the electrodes are divided previously and the voltage is applied to only the specific electrodes to obtain similar effect. For example, the length of L1-L8 is so selected that light power outputted from the optical waveguide 22 is 0, 1/8-7/8, and 1. Consequently, only one kind of voltage is applied to the respective divided electrode and an optical variable branching device which is controllable by a simple digital logic circuit is obtained. |
