Patents by Inventor Kyouzou TSUJIKAWA

Kyouzou TSUJIKAWA 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).

  • Amplifying optical fiber and optical amplifier
    Patent number: 9515450
    Abstract: A plurality of cores 51 is disposed around the center axis of a first cladding 52 in a state in which an inter-core distance ? of cores adjacent to each other is equal, a refractive index n1 of the core 51 is provided higher than a refractive index n2 of the first cladding 52, and the refractive index n2 of the first cladding 52 is provided higher than a refractive index n3 of a second cladding 53. Moreover, 5.8??/MFD(2?c/(?c+?op))?8 is satisfied, where the inter-core distance is defined as ?, a mode field diameter of the core is defined as MFD, a cutoff wavelength is defined as ?c, and a wavelength of communication light incident on the core 51 is defined as ?op.
    Type: Grant
    Filed: October 31, 2013
    Date of Patent: December 6, 2016
    Assignees: FUJIKURA LTD., NIPPON TELEGRAPH AND TELEPHONE CORPORATION, OSAKA PREFECTURE UNIVERSITY PUBLIC CORPORATION, NATIONAL UNIVERSITY CORPORATION SHIMANE UNIVERSITY
    Inventors: Shoichiro Matsuo, Katsuhiro Takenaga, Kentaro Ichii, Hirotaka Ono, Kyouzou Tsujikawa, Makoto Yamada, Hiroji Masuda
  • Amplifying optical fiber and optical amplifier
    Patent number: 9252556
    Abstract: The first cladding 52 has a two-layer structure formed of a solid inner layer 62A passed through the center axis of the first cladding 52 and an outer layer 62B enclosing the inner layer 62A and the plurality of cores 51 with no gap. A refractive index n1 of the core 51 is provided higher than refractive indexes n2A and n2B of the inner layer 62A and the outer layer 62B, the refractive indexes n2A and n2B of the inner layer 62A and the outer layer 62B are provided higher than a refractive index n3 of the second cladding 53, and the refractive index n2A of the inner layer 62A is provided lower than the refractive index n2B of the outer layer 62B.
    Type: Grant
    Filed: October 31, 2013
    Date of Patent: February 2, 2016
    Assignees: FUJIKURA LTD., NIPPON TELEGRAPH AND TELEPHONE CORPORATION, OSAKA PREFECTURE UNIVERSITY PUBLIC CORPORATION, NATIONAL UNIVERSITY CORPORATION SHIMANE UNIVERSITY
    Inventors: Shoichiro Matsuo, Katsuhiro Takenaga, Kentaro Ichii, Hirotaka Ono, Kyouzou Tsujikawa, Makoto Yamada, Hiroji Masuda
  • AMPLIFYING OPTICAL FIBER AND OPTICAL AMPLIFIER
    Publication number: 20150318659
    Abstract: A plurality of cores 51 is disposed around the center axis of a first cladding 52 in a state in which an inter-core distance ? of cores adjacent to each other is equal, a refractive index n1 of the core 51 is provided higher than a refractive index n2 of the first cladding 52, and the refractive index n2 of the first cladding 52 is provided higher than a refractive index n3 of a second cladding 53. Moreover, 5.8??/MFD(2?c/(?c+?op))?8 is satisfied, where the inter-core distance is defined as ?, a mode field diameter of the core is defined as MFD, a cutoff wavelength is defined as ?c, and a wavelength of communication light incident on the core 51 is defined as ?op.
    Type: Application
    Filed: October 31, 2013
    Publication date: November 5, 2015
    Applicants: FUJIKURA LTD., NIPPON TELEGRAPH AND TELEPHONE CORPORATION, OSAKA PREFECTURE UNIVERSITY PUBLIC CORPORATION, NATIONAL UNIVERSITY CORPORATION SHIMANE UNIVERSITY
    Inventors: Shoichiro Matsuo, Katsuhiro Takenaga, Kentaro Ichii, Hirotaka Ono, Kyouzou Tsujikawa, Makoto Yamada, Hiroji Masuda
  • AMPLIFYING OPTICAL FIBER AND OPTICAL AMPLIFIER
    Publication number: 20150318661
    Abstract: The first cladding 52 has a two-layer structure formed of a solid inner layer 62A passed through the center axis of the first cladding 52 and an outer layer 62B enclosing the inner layer 62A and the plurality of cores 51 with no gap. A refractive index n1 of the core 51 is provided higher than refractive indexes n2A and n2B of the inner layer 62A and the outer layer 62B, the refractive indexes n2A and n2B of the inner layer 62A and the outer layer 62B are provided higher than a refractive index n3 of the second cladding 53, and the refractive index n2A of the inner layer 62A is provided lower than the refractive index n2B of the outer layer 62B.
    Type: Application
    Filed: October 31, 2013
    Publication date: November 5, 2015
    Applicants: FUJIKURA LTD., NIPPON TELEGRAPH AND TELEPHONE CORPORATION, OSAKA PREFECTURE UNIVERSITY PUBLIC CORPORATION, NATIONAL UNIVERSITY CORPORATION SHIMANE UNIVERSITY
    Inventors: Shoichiro Matsuo, Katsuhiro Takenaga, Kentaro Ichii, Hirotaka Ono, Kyouzou Tsujikawa, Makoto Yamada, Hiroji Masuda
  • Optical fiber having holes
    Patent number: 9121995
    Abstract: Each of a first clad region (12) and a second clad region (13) has holes (12a, 13a) which have identical diameters and are periodically formed so that the first clad region (12) and the second clad region (13) each have an effective refractive index lower than a refractive index of a core region (11), the effective refractive index of the first clad region (12) being lower than that of the second clad region (13).
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: September 1, 2015
    Assignees: FUJIKURA LTD., NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Shoji Tanigawa, Katsuhiro Takenaga, Shoichiro Matsuo, Takashi Matsui, Taiji Sakamoto, Kyouzou Tsujikawa, Shigeru Tomita
  • OPTICAL FIBER
    Publication number: 20120288247
    Abstract: Each of a first clad region (12) and a second clad region (13) has holes (12a, 13a) which have identical diameters and are periodically formed so that the first clad region (12) and the second clad region (13) each have an effective refractive index lower than a refractive index of a core region (11), the effective refractive index of the first clad region (12) being lower than that of the second clad region (13).
    Type: Application
    Filed: July 26, 2012
    Publication date: November 15, 2012
    Applicants: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, FUJIKURA LTD.
    Inventors: Shoji TANIGAWA, Katsuhiro TAKENAGA, Shoichiro MATSUO, Takashi MATSUI, Taiji SAKAMOTO, Kyouzou TSUJIKAWA, Shigeru TOMITA