| 摘要 |
PURPOSE:To obtain a high extinction ratio and to reduce the size of an optical switch so that the switch is made suitable for matrix integrally forming coupling sections of the 1st and 2nd optical waveguides to a prescribed length. CONSTITUTION:A cross state is maintained when a voltage is not impressed to an electrode 3. The incident light on the optical waveguide 2 is propagated to the optical waveguide 2' via the coupling section 4. The voltage is impressed to the electrodes 5, 6 in this stage and the refractive index in this part is changed so that the width of the coupling section 4 is made 2d1. The refractive index in the central part of the coupling section 4 changes and the waveguides 2, 2' are separated to attain the non-cross state when the voltage is impressed to the electrode 3. The width of the waveguides 2, 2' is narrowed by W1/2 by the refractive index change in the central part. However, the parts of the electrodes 5, 6 are expanded as the optical waveguide if the voltage is not impressed to the electrodes 5, 6. As a result, the width of the waveguides 2, 2' can be maintained at the specified value d1. The length of the coupling section 4 is thus reduced and the size of the switch is reduced. |
