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.

Date of Patent:
Jul. 12, 2016

Filed:

Aug. 08, 2014
Applicant:

Kabushiki Kaisha Toshiba, Minato-ku, JP;

Inventors:

Kinichi Sasaki, Tokyo, JP;

Masao Takahashi, Kanagawa-ken, JP;

Yukihisa Hirata, Tokyo, JP;

Assignee:

KABUSHIKI KAISHA TOSHIBA, Minato-ku, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B 9/02 (2006.01); G01R 15/24 (2006.01); G01D 5/353 (2006.01); G01R 19/00 (2006.01);
U.S. Cl.
CPC ...
G01R 15/246 (2013.01); G01D 5/35322 (2013.01); G01R 19/0092 (2013.01);
Abstract

In one embodiment, a Sagnac interferometer-type fiber-optic sensor includes a synchronous detection circuit to carry out synchronous detection of detected light signal with a phase modulation angular frequency of a phase modulator. A signal processing circuit calculates and outputs the magnitude of current to be measured using the signal detected in the synchronous detection circuit. A phase modulator driving circuit controls the driving of the phase modulator. The phase modulator driving circuit controls a phase modulation depth of the phase modulator so that the amplitude of the second-order harmonics and the fourth-order harmonics obtained by carrying out the synchronous detection of the detected light signal with the phase modulation angular frequency becomes the same.


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