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:
May. 12, 2026
Filed:
Feb. 22, 2021
Fujikura Ltd., Tokyo, JP;
Fujikura Ltd., Tokyo, JP;
Abstract
An active element added-optical fiber includes a core, having a radius d and including a first region and a second region, and a cladding that surrounds an outer peripheral surface of the core without a gap and propagates light in a few mode. The first region is a region from a central axis of the core to a radius ra and contains ytterbium as an active element. The second region is a region to the radius d that surrounds the first region without a gap and contains a plurality of dopants, one of which is germanium. The active element is not added to a region within the second region from a radius rc to the radius d. The germanium is not added to a region within the first region from the central axis to a radius rb, and a concentration of the germanium is highest among the plurality of dopants.