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:
Mar. 09, 1999
Filed:
Oct. 21, 1997
Haruyoshi Uchiyama, Tokyo, JP;
Ando Electric Co., Ltd., Tokyo, JP;
Abstract
The objective of the present invention is to offer an optical fiber strain-measuring apparatus, which allows the detecting of the amount of strain at an arbitrary distance within a test optical fiber as well as the distance strain distribution, and facilitates the detecting of the back scattered light. In order to achieve the above objective, the present invention comprises an acousto-optic switch 108 which outputs a measuring pulse light, an optical circulator 112 which forwards the measuring pulse light to an optical ring circuit possessing a test optical fiber 124, while allowing the natural Brillouin back scattered light generated from the test optical fiber 124 to travel through the optical ring circuit, a frequency conversion section 132 to successively convert the reference light outputted from an optical directional coupler 102 into a reference pulse train which has its frequency change into a step form, and an acousto-optic switch 134 to output the reference pulse train as a sampling pulse, and the sampling pulse and the natural Brillouin back scattered light outputted from the optical ring circuit are converted into electrical signals by the opto-electric conversion section 138, and the signal processing section 146 measures the strain of the test optical fiber 124 based on these electrical signals.