JPS57173819A - Optical switch - Google Patents

Abstract

PURPOSE:To obtain an excellent optical switch used for a small-sized device, etc., by covering the surface of a substrate with a protective film, providing grooves meeting at right angles with each other, on the film, embedding an optical propagation medium in the grooves, forming an optical waveguide, and providing a black diffraction grating and one pair of electrodes on said crossing part. CONSTITUTION:A substrate 22 of a sapphire, etc. is covered with a protective film 231 of SiO2, etc., grooves 232 meeting at right angles with each other are formed on the film 231, an optical propagation medium 233 of PbTiO3, etc. is embedded in the grooves, and an optical waveguide 23 is formed. On a crossing part 24 of the optical waveguide 23, a black grating 25 for executing the black diffraction is formed by a transparent conductive film. One pair of electrodes 26 are formed in the proximity of the grating 25. In this case, the optical propagation medium 233 whose refractive index is larger than the surface of the film 231 and the substrate 22 is used. Also, as for the refractive index of th grating 25, a material whose refractive index is smaller than the medium 233 is used. In this way, it is possible to easily form an excellent optical switch which is high in its integration degree and suitable for an optical IC, etc. A comb line electrode can be formed by making it serve as the black grating and the electrode.