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:
Jul. 26, 1994
Filed:
Sep. 14, 1993
Hajime Sakata, Hiratsuka, JP;
Hitoshi Oda, Sagamihara, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical device comprises a substrate, a first guiding layer having a guided mode provided on the substrate, a second guiding layer laminated with the first guiding layer on the substrate, the second guiding layer having a guided mode different from that of the first guiding layer, and a diffraction grating provided on an area where the first and second guiding layers have their guided modes overlapping, the diffraction grating serving to couple the light on the specific range of wavelengths that propagate through the first guiding layer, with the second layer, wherein the diffraction grating comprises a high refractive index region and a low refractive index region disposed periodically in the propagation direction of light, the ratio of the high refractive index region to the low refractive index region occupied in one period changing gradually in the propagation direction of light.