Patents by Inventor Koji Batou

Koji Batou 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-level control method, optical-level control apparatus and wavelength-multiplexing optical network
    Patent number: 7466478
    Abstract: An optical-level control apparatus includes a plurality of variable optical attenuators each used for attenuating an input optical signal included in a wavelength division multiplexing signal as a component having a specific wavelength by applying a variable attenuation quantity, a plurality of control units each used for executing automatic control for automatically controlling the attenuation quantity in order to adjust the optical level of an optical signal output by a corresponding one of the variable optical attenuators to a target level in an ordinary normal state of the input optical signal, and a detection unit for detecting a loss of light failure of an optical signal input to each of the variable optical attenuators and detecting disappearance of the loss of light failure.
    Type: Grant
    Filed: March 15, 2005
    Date of Patent: December 16, 2008
    Assignee: Fujitsu Limited
    Inventors: Takuji Maeda, Haruki Tanaka, Hisayuki Ojima, Hiroaki Tomofuji, Hideaki Sugiya, Koji Batou
  • Optical-level control method, optical-level control apparatus and wavelength-multiplexing optical network
    Publication number: 20050168806
    Abstract: An optical-level control apparatus includes a plurality of variable optical attenuators each used for attenuating an input optical signal included in a wavelength division multiplexing signal as a component having a specific wavelength by applying a variable attenuation quantity, a plurality of control units each used for executing automatic control for automatically controlling the attenuation quantity in order to adjust the optical level of an optical signal output by a corresponding one of the variable optical attenuators to a target level in an ordinary normal state of the input optical signal, and a detection unit for detecting a loss of light failure of an optical signal input to each of the variable optical attenuators and detecting disappearance of the loss of light failure.
    Type: Application
    Filed: March 15, 2005
    Publication date: August 4, 2005
    Applicant: Fujitsu Limited
    Inventors: Takuji Maeda, Haruki Tanaka, Hisayuki Ojima, Hiroaki Tomofuji, Hideaki Sugiya, Koji Batou