Patents by Inventor Kiyoaki Takashina

Kiyoaki Takashina 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).

  • Gain profile measuring method and system and gain profile controlling method and system
    Patent number: 7009693
    Abstract: To control a gain profile in an optical fiber line to become a desirable form, a C-OTDR measuring apparatus (36) outputs a probe pulse light having a wavelength ?m for an optical fiber line (14). A power level on the input or output side of a variable gain equalizer (22) can be measured according to a C-OTDR waveform of a return light of the probe pulse light entered through a C-OTDR path (20c) and an optical fiber line (16). By sweeping the measurement wavelength ?m, the gain file is measured. The equalizing characteristics of the variable gain equalizer (22) are remotely controlled so that the gain profile becomes a desirable form according to the measured result.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: March 7, 2006
    Assignees: KDDI Submarine Cable Systems Inc., Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kiyoaki Takashina, Toshio Kawazawa, Koji Goto
  • Gain profile measuring method and system and gain profile controlling method and system
    Publication number: 20030231888
    Abstract: To control a gain profile in an optical fiber line to become a desirable form, a C-OTDR measuring apparatus (36) outputs a probe pulse light having a wavelength &lgr;m for an optical fiber line (14). A power level on the input or output side of a variable gain equalizer (22) can be measured according to a C-OTDR waveform of a return light of the probe pulse light entered through a C-OTDR path (20c) and an optical fiber line (16). By sweeping the measurement wavelength &lgr;m, the gain file is measured. The equalizing characteristics of the variable gain equalizer (22) are remotely controlled so that the gain profile becomes a desirable form according to the measured result.
    Type: Application
    Filed: June 6, 2003
    Publication date: December 18, 2003
    Inventors: Kiyoaki Takashina, Toshio Kawazawa, Koji Goto