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:
Mar. 25, 2014
Filed:
Aug. 15, 2011
Hideaki Okayama, Tokyo, JP;
Hideaki Okayama, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
An optical wavelength filter has optical waveguides each of which includes a cladding layer and a core having a refractive index that is as high as that of the cladding layer by a factor of 1.4 or more. Each optical waveguide is partitioned into a reference section providing a reference and an adjustment section for adjusting phase differences. The reference section of each optical waveguide is so set that the optical waveguide in this section has a first equivalent refractive index and a first length. The adjustment section is so set that the waveguide in this adjustment section has a second equivalent refractive index and a second length. Two waves of light outputted from the output ends of adjacent two of the optical waveguides interfere with each other with a predetermined phase difference, thereby accomplishing independency of temperature and dimensional error.