The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 1987
Filed:
Aug. 27, 1986
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A light modulation device according to the present invention comprises a substrate, a substrate layer, an optical waveguide layer, and buffer layers, in the order from the bottom upward, all formed of either n-type or p-type compound semiconductor crystal. In this light modulation device, in order to capture the light in the optical waveguide layer, the composition ratio of the compound semiconductor is so determined that refractive index is at least approximately 0.1% higher in the optical waveguide layer than in the substrate layer and in the buffer layers. Further, the carrier density is low in the optical waveguide layer and in the buffer layers so that the applied voltage is applied mainly to the optical waveguide layer. Because of such construction, the light modulation device according to the present invention is free from strict conditions required in an etching process, is small in absorption loss of light, and can be used as a component of monolithic optical integrated circuit.