Patents by Inventor Akito Chiba

Akito Chiba 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).

  • Method for evaluating characteristic of optical modulator having mach-zehnder interferometer
    Patent number: 8867042
    Abstract: A method for evaluating a characteristic of, especially, each of Mach-Zehnder interferometers (MZIs) of an optical modulator. The method includes a step of measuring the intensity of the output of the optical modulator containing MZIs and a step of evaluating a characteristic of each MZI by using the sideband. The output intensity measuring step is the one of measuring the intensity Sn,k of the sideband signal contained in the output light from the optical modulator. The characteristic evaluating step is the one of evaluating a characteristic of the MZIk by using the Sn,k.
    Type: Grant
    Filed: September 7, 2009
    Date of Patent: October 21, 2014
    Assignees: National Institute of Information and Communications Technology, Sumitomo Osaka Cement Co., Ltd.
    Inventors: Tetsuya Kawanishi, Akito Chiba, Junichiro Ichikawa, Masaaki Sudo
  • Quadrature amplitude modulation signal generating device
    Patent number: 8676060
    Abstract: A quadrature amplitude modulation (QAM) signal generator, which can obtain optical signals such as QAM signals without handling multilevel electrical signals, can be produced by using a plurality of parallel Mach-Zehnder modulators (MZMs), such as quadruplex parallel MZMs (QPMZM). The quadrature amplitude modulation (QAM) signal generator includes a first waveguide, a first quadrature phase-shift-keying (QPSK) signal generator provided on the first waveguide, a second waveguide connected with the first waveguide at a wave-combining point, and a second quadrature phase-shift-keying (QPSK) signal generator provided on the second waveguide.
    Type: Grant
    Filed: January 31, 2008
    Date of Patent: March 18, 2014
    Assignee: National Institute of Information and Communications Technology
    Inventors: Tetsuya Kawanishi, Takahide Sakamoto, Akito Chiba, Masahiro Tsuchiya
  • METHOD FOR EVALUATING CHARACTERISTIC OF OPTICAL MODULATOR HAVING MACH-ZEHNDER INTERFEROMETER
    Publication number: 20120162656
    Abstract: A method for evaluating a characteristic of, especially, each of Mach-Zehnder interferometers (MZIs) of an optical modulator. The method includes a step of measuring the intensity of the output of the optical modulator containing MZIs and a step of evaluating a characteristic of each MZI by using the sideband. The output intensity measuring step is the one of measuring the intensity Sn,k of the sideband signal contained in the output light from the optical modulator. The characteristic evaluating step is the one of evaluating a characteristic of the MZIk by using the Sn,k.
    Type: Application
    Filed: September 7, 2009
    Publication date: June 28, 2012
    Inventors: Tetsuya Kawanishi, Akito Chiba, Junichiro Ichikawa, Masaaki Sudo
  • QUADRATURE AMPLITUDE MODULATION SIGNAL GENERATING DEVICE
    Publication number: 20100202785
    Abstract: A quadrature amplitude modulation (QAM) signal generator, which can obtain optical signals such as QAM signals without handling multilevel electrical signals, can be produced by using a plurality of parallel Mach-Zehnder modulators (MZMs), such as quadruplex parallel MZMs (QPMZM). The quadrature amplitude modulation (QAM) signal generator includes a first waveguide, a first quadrature phase-shift-keying (QPSK) signal generator provided on the first waveguide, a second waveguide connected with the first waveguide at a wave-combining point, and a second quadrature phase-shift-keying (QPSK) signal generator provided on the second waveguide.
    Type: Application
    Filed: January 31, 2008
    Publication date: August 12, 2010
    Applicant: National Institute of Information and Communications Technology
    Inventors: Tetsuya Kawanishi, Takahide Sakamoto, Akito Chiba, Masahiro Tsuchiya