Patents by Inventor Shinji Minakawa

Shinji Minakawa 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).

  • Noise figure measuring system for optical amplifier
    Patent number: 6900929
    Abstract: A noise figure measuring system including a first optical amplifier whose noise figure is to be measured, a plurality of light sources for outputting a plurality of optical signals having different wavelengths, respectively, an optical multiplexer for wavelength division multiplexing the plurality of optical signals output from the light sources to obtain WDM signal light, and a second optical amplifier for amplifying the WDM signal light output from the optical multiplexer. The noise figure measuring system further includes an optical spectrum measuring unit for measuring output signals from the first and second amplifiers, a power deviation detecting unit for detecting a deviation in power between the optical signals of the WDM signal light to be input into the first optical amplifier, and a light source power control unit for controlling the light sources so that the powers of the optical signals of the WDM signal light to be input into the first optical amplifier becomes substantially equal to each other.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: May 31, 2005
    Assignee: Fujitsu Limited
    Inventor: Shinji Minakawa
  • Noise figure measuring system for optical amplifier
    Publication number: 20030053193
    Abstract: A noise figure measuring system including a first optical amplifier whose noise figure is to be measured, a plurality of light sources for outputting a plurality of optical signals having different wavelengths, respectively, an optical multiplexer for wavelength division multiplexing the plurality of optical signals output from the light sources to obtain WDM signal light, and a second optical amplifier for amplifying the WDM signal light output from the optical multiplexer. The noise figure measuring system further includes an optical spectrum measuring unit for measuring output signals from the first and second amplifiers, a power deviation detecting unit for detecting a deviation in power between the optical signals of the WDM signal light to be input into the first optical amplifier, and a light source power control unit for controlling the light sources so that the powers of the optical signals of the WDM signal light to be input into the first optical amplifier becomes substantially equal to each other.
    Type: Application
    Filed: January 23, 2002
    Publication date: March 20, 2003
    Applicant: Fujitsu Limited
    Inventor: Shinji Minakawa