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:
Sep. 28, 2004
Filed:
Aug. 12, 2002
Phase difference calculation method, device, and system using optical fiber ring interference sensor
Tetsu Takashima, Chiba, JP;
Shin-ichi Nikaido, Chiba, JP;
Takeshi Togura, Chiba, JP;
Shin-ichi Niimi, Chiba, JP;
Fujikura Ltd., Tokyo, JP;
Abstract
A phase difference calculation method, a device ( ), and a system ( ) are disclosed. In an optical fiber ring interference sensor ( ) using a 3×3 optical splitting coupler ( ) and an optical splitting coupler ( ), linear sections are determined in advance, where a relationship between a phase difference &thgr; of propagation lights and an intensity Ppdn (n=1, 2, 3) outputted from each photo detector ( ) becomes approximately linear. The intensity Ppdn of an interference light, between propagation lights in CW and CCW directions in an optical fiber loop ( ), having a difference non-reciprocal phase bias is measured not less than two times. A phase difference &thgr; is then calculated based on the intensity Ppdn in the linear sections.