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:
Oct. 03, 2017
Filed:
Feb. 28, 2014
Hitachi, Ltd., Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
It is made possible to amplify signal light of an optical fiber sensor and to perform measurement in a long distance. At least one of a plurality of core wires in a multicore optical fiber is used as a signal-light propagating core wireand the other is used as a reference-light propagating core wire. Also, homodyne detection of signal light and reference light reflected by an FBG sensor unitarranged in each measurement point is performed. Thus, signal light is amplified. In order to make a difference between optical path lengths of the signal light and the reference light equal to or smaller than a coherence length, an optical path-length adjustment unit including a piezoelectric element or the like is arranged in an optical path of the reference light.