OPTICAL SWITCH

PURPOSE:To perform optical path switching whose cross talk is prevented securely by providing an electrode for waveguide switching on or near the intersection part of waveguides on the surface of a substrate, and byproviding an electrode for cross talk prevention on the exit-side waveguide. CONSTITUTION:On a substrate 5 made of an optical crystal body, etc., metal such as titanium is vapor-deposited in belts and then diffused by a heat treatment to form two crossing waveguides consisting of parts 1 and 4, and 2 and 3. On the exit-side waveguide 4, an electrode 8 for cross talk prevention is provided. When a switching electrode 6 and the electrode 8 are applied with voltages which have the same potential, light incident from the waveguide 1 is changed in cource to the waveguide 3 by a change in refractivity in the waveguide due to the DC voltage, etc., applied to the switching electrode 6. At this time, light leaking without being reflected under the switching electrode 6 travels straight to the waveguide 4, but is reflected under the electrode 8 for cross talk prevention, so that no light is incident to the waveguide 4. Thus, cross talk is prevented securely.