Patents by Inventor Tasuku Fujieda

Tasuku Fujieda 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).

  • Raman amplifier and optical communication system
    Patent number: 7768698
    Abstract: A Raman amplifier includes a pumping light source, an optical coupler, and a Raman amplifier medium. The pumping light source outputs a pumping light that is intensity-modulated with a frequency equal to or higher than 100 megahertz. The optical coupler couples the pumping light with a carrier light. The Raman amplification medium is pumped by the pumping light to amplify the carrier light. The Raman amplification medium has characteristics of a low dispersion and a small difference between propagation times of the carrier light and the pumping light.
    Type: Grant
    Filed: August 30, 2004
    Date of Patent: August 3, 2010
    Assignees: Independent Administrative Institution, Japan Agency for Marine-Earth Science and Technology, Mitsubishi Electric Corporation
    Inventors: Toshiyuki Tokura, Katsuhiro Shimizu, Tasuku Fujieda, Ken'ichi Asakawa, Hitoshi Mikada, Katsuyoshi Kawaguchi
  • Submarine observation apparatus and submarine observation system
    Patent number: 7437070
    Abstract: In each of a plurality of submarine observation apparatus (1 to n), a branching unit (63) branches fixed-wavelength light (?1) from an incoming wavelength-multiplexed light signal. An observation signal modulating unit (64) modulates the intensity of the branched fixed-wavelength light (?1) with observation information multiplexed by an observation signal multiplex unit (61). A combining unit (65) combines light signals (?2) to (?n) passing through the branching unit (63) and the fixed-wavelength light (?1a) modulated by the observation signal modulating unit (64) into a composite light signal, and outputs it to an optical fiber (12a). Therefore, in each of the plurality of submarine observation apparatus (1 to n), there is no necessity for providing a wavelength-division-multiplexing-transmission optical transmitter which requires high wavelength stability.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: October 14, 2008
    Assignees: Mitsubishi Denki Kabushiki Kaisha, Japan Agency for Marine-Earth Science and Technology
    Inventors: Tasuku Fujieda, Hideki Goto, Kenichi Asakawa, Hitoshi Mikada, Katsuyoshi Kawaguchi
  • Raman Amplifier And Optical Communication System
    Publication number: 20080013161
    Abstract: A Raman amplifier includes a pumping light source, an optical coupler, and a Raman amplifier medium. The pumping light source outputs a pumping light that is intensity-modulated with a frequency equal to or higher than 100 megahertz. The optical coupler couples the pumping light with a carrier light. The Raman amplification medium is pumped by the pumping light to amplify the carrier light. The Raman amplification medium has characteristics of a low dispersion and a small difference between propagation times of the carrier light and the pumping light.
    Type: Application
    Filed: August 30, 2004
    Publication date: January 17, 2008
    Applicants: INDEPENDENT ADMINISTRATIVE INSTITUTION, JAPAN AGENCY FOR MARINE-EARTH SCIENCE AND TECHNOLOGY, MITSUBISHI ELECTRIC CORPORATION
    Inventors: Toshiyuki Tokura, Katsuhiro Shimizu, Tasuku Fujieda, Ken'ichi Asakawa, Hitoshi Mikada, Katsuyoshi Kawaguchi
  • Submarine observation apparatus and submarine observation system
    Publication number: 20050259998
    Abstract: In each of a plurality of submarine observation apparatus (1 to n), a branching unit (63) branches fixed-wavelength light (?1) from an incoming wavelength-multiplexed light signal. An observation signal modulating unit (64) modulates the intensity of the branched fixed-wavelength light (?1) with observation information multiplexed by an observation signal multiplex unit (61). A combiningunit (65) combines lightsignals (?2) to (?n) passing through the branching unit (63) and the fixed-wavelength light (?1a) modulated by the observation signal modulating unit (64) into a composite light signal, and outputs it to an optical fiber (12a). Therefore, in each of the plurality of submarine observation apparatus (1 to n), there is no necessity for providing a wavelength-division-multiplexing-transmission optical transmitter which requires high wavelength stability.
    Type: Application
    Filed: February 18, 2005
    Publication date: November 24, 2005
    Applicants: MITSUBISHI DENKI KABUSHIKI KAISHA, Japan Agency for Marine-Earth Science and Tech.
    Inventors: Tasuku Fujieda, Hideki Goto, Kenichi Asakawa, Hitoshi Mikada, Katsuyoshi Kawaguchi