Patents by Inventor Takaaki Kakitsuka

Takaaki Kakitsuka 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).

  • Publication number: 20120155502
    Abstract: The objective of the invention is to provide a photonic crystal device which enables efficient confinement of carriers while preventing the deterioration of device characteristics. Specifically a photonic crystal device has a photonic crystal in which media with different refractive indexes are regularly arranged, wherein an active region (11) includes an active layer (12) and carrier confinement layers (13, 14) provided on the top and bottom of the active layer (12) respectively for confining carriers. The photonic crystal is formed by a buried growth layer (15) with a larger bandgap than that of the active region (11).
    Type: Application
    Filed: September 1, 2010
    Publication date: June 21, 2012
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shinji Matsuo, Takaaki Kakitsuka, Masaya Notomi, Akihiko Shinya
  • Publication number: 20100202776
    Abstract: There is provided an optical modulation signal generating device in which an operation speed is not limited by a relaxation oscillation frequency of a laser, and high-speed modulation and long-distance transmission can be performed. The optical modulation signal generating device converts a signal from a signal source into an optical signal and outputs the optical signal to a transmission medium having frequency dispersion. The optical modulation signal generating device includes an optical source (102) for performing frequency modulation by the signal from the signal source to generate an optical signal having only a frequency modulation component, and a frequency filter (103) for converting the frequency modulation component of the optical signal into an intensity modulation component and a frequency modulation component.
    Type: Application
    Filed: June 25, 2008
    Publication date: August 12, 2010
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takaaki Kakitsuka, Shinji Matsuo, Toru Segawa, Hiroyuki Suzuki