Optical frequency domain reflectometer for use as an optical fiber testing device
 In the primary invention of this application, an optical-fiber inspection device which detects the distance to a reflection point within the DUT and the amount of reflected light by dividing into two a laser beam which is possible to be frequency-swept, making one of the divided light beams incident to an optical detector via the reference light path, while making the other of the divided light beams incident to the DUT and making the light reflected within the DUT incident to the said optical detector, and analyzing the frequency of the interference signal for the two beams obtained by the optical detector, is configured so that the final reference light is obtained by providing an optical coupler in the reference light path and, after taking out a part of the reference light and making it pass through an optical frequency shifter, combining this again with the original reference light with the said optical coupler. 
Yokogawa Electric Corporation
G
G01M
inventional
Yoshihiko Yasuyuki Makoto Yoshihiro Takaaki Mamoru
Tachikawa Suzuki Komiyama Sampei Hirata Arihara