Patents by Inventor Hiroshi Kutami

Hiroshi Kutami 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: 20090084141
    Abstract: An optical fiber is formed by performing vapor phase deposition of SiO2 on the outside of a glass rod comprising a core section and a first cladding section and drawing a glass preform which formed by a second cladding section. Also, a single mode optical fiber is manufactured so that the ratio of the diameter D of the first cladding section and the diameter d of the core section is in a range of 4.0 to 4.8, and OH concentration is 0.1 ppm or less. Also, an optical fiber is manufactured so that a value of D/d>4.8, and the OH concentration is 0. 1 ppm or less. It is thereby possible to maintain an initial loss in the 1380 nm wavelength range even if hydrogen diffusion occurs.
    Type: Application
    Filed: December 4, 2008
    Publication date: April 2, 2009
    Applicant: FUJIKURA LTD.
    Inventors: Tomohiro Nunome, Hiroshi Kutami, Manabu Saitou, Kenji Okada, Munehisa Fujimaki, Koichi Harada
  • Patent number: 7440663
    Abstract: A single-mode optical fiber has a cut-off wavelength of 1260 nm or less, a zero-dispersion wavelength in the range of 1300 nm to 1324 nm, a zero-dispersion slope of 0.093 ps/nm2/km or less, a mode field diameter at a wavelength of 1310 nm in the range of 5.5 ?m to 7.9 ?m, and a bending loss of 0.5 dB or less at a wavelength of 1550 nm, the bending loss being produced when the fiber is wound around a 10-mm radius for 10 turns.
    Type: Grant
    Filed: February 26, 2007
    Date of Patent: October 21, 2008
    Assignee: Fujikura Ltd.
    Inventors: Shoichiro Matsuo, Hiroshi Kutami, Kuniharu Himeno, Hiroyuki Sawano
  • Publication number: 20070147756
    Abstract: A single-mode optical fiber has a cut-off wavelength of 1260 nm or less, a zero-dispersion wavelength in the range of 1300 nm to 1324 nm, a zero-dispersion slope of 0.093 ps/nm2/km or less, a mode field diameter at a wavelength of 1310 nm in the range of 5.5 ?m to 7.9 ?m, and a bending loss of 0.5 dB or less at a wavelength of 1550 nm, the bending loss being produced when the fiber is wound around a 10-mm radius for 10 turns.
    Type: Application
    Filed: February 26, 2007
    Publication date: June 28, 2007
    Applicant: FUJIKURA LTD
    Inventors: Shoichiro Matsuo, Hiroshi Kutami, Kuniharu Himeno, Hiroyuki Sawano
  • Publication number: 20060115224
    Abstract: A single-mode optical fiber, cable, cord, and a method for ensuring a service life of the fiber are provided. The fiber has a core and a cladding, the fiber having a cut-off wavelength that exhibits a single-mode transmission in a 1.31 ?m wavelength band. A relative refractive index difference of the core with respect to the cladding is adjusted such that a bending loss, when a bend is applied in a radius smaller than a limit bending radius of the fiber, becomes greater than a detection limit value. The limit bending radius is calculated from a relationship between a bending radius applied to the optical fiber and a failure probability which occurs after a time period. The method includes measuring a loss and ensuring that a failure probability of the fiber during a service life falls within a failure probability used for setting the limit bending radius.
    Type: Application
    Filed: November 28, 2005
    Publication date: June 1, 2006
    Inventors: Hiroshi Kutami, Shoichiro Matsuo, Kuniharu Himeno
  • Patent number: 6694079
    Abstract: A dispersion-shifted optical fiber is obtained that has a refractive index distribution shape comprising a center core portion of high refractive index, a step core portion of lower refractive index than the center core portion, provided about the outer circumference thereof, and clad of lower refractive index than the step core portion, provided about the outer circumference of the step core, in which, by suitably setting structural parameters, both Aeff expansion and dispersion slope reduction are satisfactorily effected, simultaneously, under conditions that the optical fiber is substantially single-mode, and bending loss is held down to 100 dB/m or lower.
    Type: Grant
    Filed: March 21, 2001
    Date of Patent: February 17, 2004
    Assignee: Fujikura Ltd.
    Inventors: Shoichiro Matsuo, Hiroshi Kutami, Shoji Tanigawa
  • Publication number: 20030110811
    Abstract: An optical fiber is formed by performing vapor phase deposition of SiO2 on the outside of a glass rod comprising a core section and a first cladding section and drawing a glass preform which formed by a second cladding section. Also, a single mode optical fiber is manufactured so that the ratio of the diameter D of the first cladding section and the diameter d of the core section is in a range of 4.0 to 4.8, and OH concentration is 0.1 ppm or less. Also, an optical fiber is manufactured so that a value of D/d>4.8, and the OH concentration is 0.1 ppm or less. It is thereby possible to maintain an initial loss in the 1380 nm wavelength range even if hydrogen diffusion occurs.
    Type: Application
    Filed: November 26, 2002
    Publication date: June 19, 2003
    Applicant: SINGLE MODE OPTICAL FIBER AND MANUFACTURING METHOD THEREFOR
    Inventors: Tomohiro Nunome, Hiroshi Kutami, Manabu Saitou, Kenji Okada, Munehisa Fujimaki, Koichi Harada