| 摘要 |
PURPOSE:To lower an operating voltage and to speed up operation by giving a specific propagation constant difference previously between both outside areas among three divided areas of an optical waveguide, and varying only the propagation constant difference of the center area and switching operation states. CONSTITUTION:The coupling area (length L) between optical waveguides 11 and 12 is divided into three areas and the propagation constant difference DELTAbetais given between both waveguides 11 and 12 in the two outside area or all three areas. This propagation constant difference DELTAbeta is given by varying the width and thickness of the optical waveguides, the diffusion quantity of Ti, etc. Then, an electrode 13 is formed only in the center area and a necessary voltage is impressed to invert the propagation constant difference between +DELTAbeta and -DELTAbeta. When the voltage is not impressed to the electrode 13 (V=0), a noncoupling state (=) is entered. On the other hand, the voltage is impressed to the electrode 13 to give the propagation constant difference -DELTAbeta between the optical waveguides 11 and 12 in the center area, and the coupling state is switched to (x). |
