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:
Feb. 06, 2001
Filed:
Aug. 04, 1997
Yukio Horiuchi, Tokyo, JP;
Shiro Ryu, Tokyo, JP;
Kokusai Denshin Denwa Kabushiki Kaisha, Tokyo, JP;
Abstract
Disposing optical fiber gratings,each reflecting a wavelength &lgr;1 which is different from a signal wavelength &lgr;s along an optical fiber line,at suitable intervals and positions. The wavelength &lgr;s of signal light is not reflected by the grating,, but transmitted through the optical fiber line,. An optical pulse tester,outputs probe pulse lights of wavelengths &lgr;0, &lgr;1, which are different from the signal wavelength &lgr;s, at slightly different times. The probe lights of the wavelengths &lgr;0, &lgr;1 are input into the optical fiber line,through an optical adding and dividing device,and transmitted through the optical fiber line,. Reflected light of the wavelength &lgr;1 of probe light contains therein reflection pulses of the grating,, and each reflection pulse serves as a position reference. The probe light of the wavelength &lgr;0 does not contain reflection light of the grating,. Comparison of the reflected lights of the wavelengths &lgr;0, &lgr;1 to each other by the optical pulse tester,, provides determination of whether there is a fault location, and, if so, detection of fault location with high precision can be made.