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:
Jan. 21, 2025
Filed:
Apr. 05, 2021
Sumitomo Electric Industries, Ltd., Osaka, JP;
Sumitomo Electric Optifrontier Co., Ltd., Yokohama, JP;
Shigehiro Nagano, Osaka, JP;
Takemi Hasegawa, Osaka, JP;
Jun Kinugasa, Yokohama, JP;
Kazuaki Masui, Yokohama, JP;
SUMITOMO ELECTRIC INDUSTRIES, LTD, Osaka, JP;
SUMITOMO ELECTRIC OPTIFRONTIER CO., LTD., Yokohama, JP;
Abstract
A gain flattening filter includes a first optical fiber that has a core, a first cladding, and a second cladding and that has a uniform composition in a length direction; and a pair of second optical fibers fused to both ends of the first optical fiber. The first optical fiber has a first section in which a slanted refractive index grating is formed and a pair of second sections connecting both ends of the first section to the pair of second optical fibers. The first cladding contains a photosensitive material whose refractive index increases upon irradiation with light having a specific wavelength. In the core, a tensile stress remains in the first section. An average MFD of the second sections is larger than an average MFD of the second optical fibers and smaller than an average MFD of the first section.