Patents by Inventor Toshio Kurashima

Toshio Kurashima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Optical fiber strain measuring apparatus
    Patent number: 5880824
    Abstract: An object of the present invention is to provide an optical fiber strain measuring apparatus which can perform precise measurement without causing any fluctuation in signal level.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: March 9, 1999
    Assignee: Ando Electric Co., Ltd.
    Inventors: Haruyoshi Uchiyama, Zhixien Li, Yasushi Satoh, Toshio Kurashima
  • Optical fiber characteristic measuring device
    Patent number: 5686986
    Abstract: Coherent light emitted from a coherent light source 1 is sent as a probe beam through a connector 31 into an optical fiber being measured. A portion of this beam is sent to an optical frequency converter 100 to form an optical pulse train having a frequency which is frequency-swept in steps of a designated frequency at a designated periodicity, and an optical pulse having a designated frequency is extracted from the optical pulse train by an electro-optic switch 18 and sent to the optical fiber being measured. Then, a signal beam exiting the optical fiber being measured is heterodyne-received by means of a local beam passing through either a connecting optical fiber 6 side or a frequency shifter 7 side according to the selection of optical switches 4 and 5. Consequently, it is possible to measure the characteristics of the optical fiber by means of a BOTDR, BOTDA or a COTDR.
    Type: Grant
    Filed: September 25, 1996
    Date of Patent: November 11, 1997
    Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone Corporation
    Inventors: Zhixien Li, Yasushi Sato, Shoji Adachi, Toshio Kurashima, Kaoru Shimizu
  • Optical cable and its manufacturing method
    Patent number: 5136673
    Abstract: An optical cable has a center member, around which a plurality of coated optical fibers are tightly stranded. Each optical fiber is given uneven strains in its longitudinal direction. Adhesive resin is applied to surround each of the coated optical fibers and binds each of them to the center member to make an integral optical unit when cured.
    Type: Grant
    Filed: May 28, 1991
    Date of Patent: August 4, 1992
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Nobuyuki Yoshizawa, Tsuneo Horiguchi, Koushi Ishihara, Tetsuro Yabuta, Toshio Kurashima, Hidenobu Tada