Patents by Inventor Hiratake Iwadate

Hiratake Iwadate 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).

  • Control system for a laser diode and a method for controlling the same
    Patent number: 6885685
    Abstract: According to the present invention, an optical transmitting system, which enables a precise control of the power and the extinction ratio of the optical output without a small amount of the preset data, will be provided. The system comprises a laser module and a control system that supplies a bias current and a modulation current to the laser module. In the present invention, one of the bias current and the modulation current of the semiconductor laser in the laser module is varied to maintain the power and the extinction ratio of the optical output, and the other of the bias current and the modulation current is calculated based on the specific function. Only coefficients of the specific function are stored in the control system. Therefore, the present invention does not need a large size of the storage in which both the bias current and the modulation current are stored as a table.
    Type: Grant
    Filed: June 9, 2003
    Date of Patent: April 26, 2005
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hirotoshi Hidaka, Hiratake Iwadate
  • Control system for a laser diode and a method for controlling the same
    Publication number: 20040032889
    Abstract: According to the present invention, an optical transmitting system, which enables a precise control of the power and the extinction ratio of the optical output without a small amount of the preset data, will be provided. The system comprises a laser module and a control system that supplies a bias current and a modulation current to the laser module. In the present invention, one of the bias current and the modulation current of the semiconductor laser in the laser module is varied to maintain the power and the extinction ratio of the optical output, and the other of the bias current and the modulation current is calculated based on the specific function. Only coefficients of the specific function are stored in the control system. Therefore, the present invention does not need a large size of the storage in which both the bias current and the modulation current are stored as a table.
    Type: Application
    Filed: June 9, 2003
    Publication date: February 19, 2004
    Inventors: Hirotoshi Hidaka, Hiratake Iwadate