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. 12, 2010
Filed:
Mar. 18, 2008
Seiji Kojima, Hitachi, JP;
Shinji Komatsuzaki, Hitachi, JP;
Seiji Kojima, Hitachi, JP;
Shinji Komatsuzaki, Hitachi, JP;
Hitachi Cable, Ltd., Tokyo, JP;
Abstract
A physical quantity measuring system according to the present invention comprises: an optical fiber having fiber Bragg gratings; a light source connected to the optical fiber; an arrayed waveguide grating connected between the light source and the optical fiber via an optical branching filter, and having output channels of which central wavelengths of at least three output channels are included in a one-tenth loss band of a reflected light by the fiber Bragg grating; light receiving devices for receiving light output from the output channels on a one-to-one basis; and a central reflected wavelength change detecting unit connected to the light receiving devices for estimating a change in a central reflected wavelength based on a physical quantity, by calculating first and second group signals from light receiving signals corresponding to the at least three output channels, and by calculating a differential signal between the first and the second group signals.