Optics: measuring and testing – Material strain analysis
Reexamination Certificate
2008-03-18
2010-10-12
Turner, Samuel A (Department: 2877)
Optics: measuring and testing
Material strain analysis
C250S227180
Reexamination Certificate
active
07812934
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.
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Seiji Kokima et al., High-speed optical wavelength interrogator using a PLC-type optical filter for fiber Bragg grating sensors', Smart Structures and Materials 2004, Proceedings of SPIE vol. 5384. p. 241-249.
NTT Electronics Corporation, Nov. 3, 2006.
NTT Electronics Corporation , Mar. 13, 2007.
Kojima Seiji
Komatsuzaki Shinji
Antonelli, Terry Stout & Kraus, LLP.
Hitachi Cable Ltd.
Turner Samuel A
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