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:
May. 12, 1992
Filed:
Jun. 22, 1990
Yasuo Ozawa, Odawara, JP;
Nobuo Ando, Hitachi, JP;
Satoshi Yamamoto, Hitachi, JP;
Toshio Fukahori, Hitachi, JP;
Hiroyuki Kunugiyama, Hitachi, JP;
Kouichi Sugiyama, Takahagi, JP;
Teruaki Tsutsui, Hitachi, JP;
Keiichi Hashiba, Hitachi, JP;
Shigehiro Endoh, Hitachi, JP;
Hiroshi Kawakami, Hitachi, JP;
Akira Tokushima, Hitachi, JP;
Kaoru Yamazaki, Kita-Ibaraki, JP;
Hitachi Cable Limited, Tokyo, JP;
The Tokyo Electric Power Company, Incorporated, Tokyo, JP;
Abstract
A fiber optic distributed temperature sensor system outputs a temperature distribution along the longitudinal direction of a sensor optical fiber by measuring the temperature dependency of Raman scattered light intensity produced in an optical fiber by use of the OTDR technique. The system is characterized in that a light output from a light source is input to the sensor (optical fiber) via an optical wavelength division demultiplexer, that among the reflected light of back scattered light returning from the sensor optical fiber, light of a particular wavelength range is reflected or transmitted by at least one optical filter of the optical wavelength division demultiplexer to separate the light of the particular wavelength range and that signal of the light of the particular wavelength range is guided to a detector of an optical measuring system.