Hitachi Cable, Inc.

The Tokyo Electric Power Company, Incorporated

Hiroyuki Kunugiyama

Katsuyuki Imoto

Satoshi Yamamoto

Toshio Fukahori

Nobuo Ando

Hiroshi Kawakami

Keiichi Hashiba

Shigehiro Endoh

Yasuo Ozawa

Akira Tokushima

Kouichi Sugiyama

Kaoru Yamazaki

Teruaki Tsutsui

An optical star coupler comprises an optical fiber bundle consisting of a plurality of optical fibers. The central portion of the optical fiber bundle is twisted, fused and pulled under heating so as to form a tapered region, and the outer peripheral portion of the tapered region is coated with a dielectric substance.

Optical star coupler and method for manufacturing the same

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.

Fiber optic distributed temperature sensor system

Growing community of inventors

Hitachi, Japan

Hiroyuki Kunugiyama