Patents by Inventor Keisei Morita

Keisei Morita 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: 20200393613
    Abstract: An optical fiber is formed from silica glass, and includes a core, a first cladding which surrounds the core and has a refractive index lower than the refractive index of the core, and a second cladding which surrounds the first cladding and has a refractive index that is lower than the refractive index of the core and higher than the refractive index of the first cladding. The second cladding is divided into an inner region that is in contact with the first cladding and an outer region which surrounds the inner region and has a thickness that is half the thickness of the second cladding or less, while being 5 ?m or more. The residual stress in at least a part of the outer region is a compressive stress.
    Type: Application
    Filed: August 27, 2020
    Publication date: December 17, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yoshiaki TAMURA, Hirotaka SAKUMA, Keisei MORITA
  • Publication number: 20200278492
    Abstract: An optical fiber includes a glass fiber and a coating resin covering an outer periphery of the glass fiber. The glass fiber includes a core, an inner cladding, a trench, and an outer cladding. An outer diameter of the glass fiber is 99 ?m or larger and 101 ?m or smaller. An outer diameter of the coating resin is 160 ?m or larger and 170 ?m or smaller. A mode field diameter for light having a wavelength of 1310 nm is 7.2 ?m or larger and 8.2 ?M or smaller. Bending loss at a wavelength of 1550 nm when wound in a ring shape having a radius of 10 mm is 0.1 dB/turn or less. Bending loss at the wavelength of 1550 nm when wound in the ring shape having the radius of 7.5 mm is 0.5 dB/turn or less.
    Type: Application
    Filed: February 20, 2020
    Publication date: September 3, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keisei MORITA, Hiroki ISHIKAWA, Sotaro IDA
  • Publication number: 20200278493
    Abstract: An optical fiber includes a glass fiber and a coating resin covering an outer periphery of the glass fiber. The glass fiber includes a core and a cladding. An outer diameter of the glass fiber is 99 ?m or larger and 101 ?m or smaller. The coating resin includes a cured material of an ultraviolet curing resin composition. An outer diameter of the coating resin is 160 ?m or larger and 170 ?m or smaller. A mode field diameter for light having a wavelength of 1310 nm is 7.2 ?m or larger and 8.2 ?m or smaller. Bending loss at a wavelength of 1550 nm when wound in a ring shape having a radius of 10 mm is 0.1 dB/turn or less. Bending loss at the wavelength of 1550 nm when wound in the ring shape having the radius of 7.5 mm is 0.5 dB/turn or less.
    Type: Application
    Filed: February 26, 2020
    Publication date: September 3, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hiroki ISHIKAWA, Keisei MORITA, Sotaro IDA
  • Publication number: 20200249393
    Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.
    Type: Application
    Filed: April 15, 2020
    Publication date: August 6, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Keisei MORITA, Yuki KAWAGUCHI
  • Patent number: 10723650
    Abstract: An optical fiber preform includes a silica-glass core portion, and a cladding portion surrounding the core portion, the cladding portion being composed of a fluorine-containing silica glass having a lower refractive index than the core portion, the core portion including a first region that does not include the central axis thereof, the first region containing a first dopant selected from sodium, potassium, and compounds thereof, and a second region that includes the central axis, the second region containing a second dopant that reduces the viscosity of the silica glass, the second dopant having a diffusion coefficient of 1×10?12 cm2/s or more and less than the first dopant at 2,000° C. to 2,300° C., in which the entire core portion has an average first dopant concentration of 10 atomic ppm or more and 2,000 atomic ppm or less and an average second dopant concentration of 10 atomic ppm or more.
    Type: Grant
    Filed: July 10, 2018
    Date of Patent: July 28, 2020
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keisei Morita, Yoshiaki Tamura, Hirotaka Sakuma
  • Patent number: 10656329
    Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.
    Type: Grant
    Filed: April 17, 2019
    Date of Patent: May 19, 2020
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka Sakuma, Yoshiaki Tamura, Keisei Morita, Yuki Kawaguchi
  • Patent number: 10550030
    Abstract: Provided is an optical fiber containing an alkali metal element or the like having a smaller diffusion coefficient than K and having a low Rayleigh scattering loss. An optical fiber is composed of silica glass and includes a core and a cladding arranged to surround the core which has a lower refractive index than the core. The core includes a first core including a central axis and a second core arranged to surround the first core. The average concentration of an alkali metal element or alkaline-earth metal element in the first core is 10 mol ppm or less. The average concentration of chlorine in the first core is 2000 mol ppm or more. The average concentration of an alkali metal element or alkaline-earth metal element in the second core is 10 mol ppm or more. The average concentration of chlorine in the second core is 10 to 600 mol ppm.
    Type: Grant
    Filed: August 23, 2018
    Date of Patent: February 4, 2020
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka Sakuma, Yoshiaki Tamura, Keisei Morita
  • Publication number: 20190324195
    Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.
    Type: Application
    Filed: April 17, 2019
    Publication date: October 24, 2019
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Keisei MORITA, Yuki KAWAGUCHI
  • Publication number: 20190292089
    Abstract: The present embodiment relates to an optical fiber preform manufacturing method in which two or more kinds of alkali metal elements are diffused and doped to an inner surface of a glass pipe. The manufacturing method includes: a first drying step performed at a temperature equal to or lower than a lowest temperature among melting point temperatures of the alkali metal salt raw materials; and a second drying step performed at a temperature which is equal to or higher than a highest temperature among the melting point temperatures of the alkali metal salt raw materials and at which vapor pressures of the alkali metal salt raw materials are 2 mmHg or lower.
    Type: Application
    Filed: June 11, 2019
    Publication date: September 26, 2019
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Keisei MORITA
  • Publication number: 20190016630
    Abstract: An optical fiber preform includes a silica-glass core portion, and a cladding portion surrounding the core portion, the cladding portion being composed of a fluorine-containing silica glass having a lower refractive index than the core portion, the core portion including a first region that does not include the central axis thereof, the first region containing a first dopant selected from sodium, potassium, and compounds thereof, and a second region that includes the central axis, the second region containing a second dopant that reduces the viscosity of the silica glass, the second dopant having a diffusion coefficient of 1×10?12 cm2/s or more and less than the first dopant at 2,000° C. to 2,300° C., in which the entire core portion has an average first dopant concentration of 10 atomic ppm or more and 2,000 atomic ppm or less and an average second dopant concentration of 10 atomic ppm or more.
    Type: Application
    Filed: July 10, 2018
    Publication date: January 17, 2019
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keisei MORITA, Yoshiaki TAMURA, Hirotaka SAKUMA
  • Publication number: 20180362392
    Abstract: Provided is an optical fiber containing an alkali metal element or the like having a smaller diffusion coefficient than K and having a low Rayleigh scattering loss. An optical fiber is composed of silica glass and includes a core and a cladding arranged to surround the core which has a lower refractive index than the core. The core includes a first core including a central axis and a second core arranged to surround the first core. The average concentration of an alkali metal element or alkaline-earth metal element in the first core is 10 mol ppm or less. The average concentration of chlorine in the first core is 2000 mol ppm or more. The average concentration of an alkali metal element or alkaline-earth metal element in the second core is 10 mol ppm or more. The average concentration of chlorine in the second core is 10 to 600 mol ppm.
    Type: Application
    Filed: August 23, 2018
    Publication date: December 20, 2018
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Keisei MORITA
  • Patent number: 10048437
    Abstract: A low attenuation optical fiber having a core doped with Ge is offered. The optical fiber consists of a glass part and a covering part formed around the glass part. The glass part is made of silica glass and includes: a Ge-doped center core region; an optical cladding layer formed around the center core region; and an optical cladding layer formed around the cladding layer. The relationship of ?1>?3??2 holds, where ?1, ?2, and ?3 are the relative refractive index differences of the center core region, the cladding layer, and the cladding layer 30, respectively with respect to pure silica glass. The average outer diameter of the glass part is in the range of 125±0.5 ?m in the longitudinal direction, and 3? is in the range of 0.1 ?m to 0.5 ?m, where ? is the standard deviation of the outer diameter in the longitudinal direction.
    Type: Grant
    Filed: August 30, 2017
    Date of Patent: August 14, 2018
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keisei Morita, Yoshinori Yamamoto
  • Patent number: 10031282
    Abstract: An optical fiber containing alkali metal elements or the like in which Rayleigh scattering loss can be reduced is provided. An optical fiber includes a core composed of silica glass and a cladding which surrounds the core, has a refractive index lower than a refractive index of the core, and is composed of silica glass containing fluorine. The core contains a first group of dopants and a second group of dopants having a diffusion coefficient lower than a diffusion coefficient of the first group of dopants. The difference between the maximum value and the minimum value of residual stress in the optical fiber is 150 MPa or less.
    Type: Grant
    Filed: September 11, 2017
    Date of Patent: July 24, 2018
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka Sakuma, Yoshiaki Tamura, Keisei Morita
  • Publication number: 20180074258
    Abstract: A low attenuation optical fiber having a core doped with Ge is offered. The optical fiber consists of a glass part and a covering part formed around the glass part. The glass part is made of silica glass and includes: a Ge-doped center core region; an optical cladding layer formed around the center core region; and an optical cladding layer formed around the cladding layer. The relationship of ?1>?3??2 holds, where ?1, ?2, and ?3 are the relative refractive index differences of the center core region, the cladding layer, and the cladding layer 30, respectively with respect to pure silica glass. The average outer diameter of the glass part is in the range of 125±0.5 ?m in the longitudinal direction, and 3? is in the range of 0.1 ?m to 0.5 ?m, where ? is the standard deviation of the outer diameter in the longitudinal direction.
    Type: Application
    Filed: August 30, 2017
    Publication date: March 15, 2018
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keisei MORITA, Yoshinori YAMAMOTO
  • Publication number: 20170371096
    Abstract: An optical fiber containing alkali metal elements or the like in which Rayleigh scattering loss can be reduced is provided. An optical fiber includes a core composed of silica glass and a cladding which surrounds the core, has a refractive index lower than a refractive index of the core, and is composed of silica glass containing fluorine. The core contains a first group of dopants and a second group of dopants having a diffusion coefficient lower than a diffusion coefficient of the first group of dopants. The difference between the maximum value and the minimum value of residual stress in the optical fiber is 150 MPa or less.
    Type: Application
    Filed: September 11, 2017
    Publication date: December 28, 2017
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Keisei MORITA
  • Patent number: 8011209
    Abstract: A method of making a glass is provided in which the time needed for doping a refractive index control substance such as fluorine into a soot glass deposit body can be reduced. The method comprises the steps of: (1) putting a soot glass deposit body in a container; (2) doping a refractive index control substance into the soot glass deposit body by supplying an doping gas into the container, the doping gas containing the substance; and (3) consolidating the soot glass deposit body by heating, wherein the final set-value concentration of the substance is determined beforehand depending on the target refractive index of the glass, and in step (2), the container is supplied with the doping gas including the substance having a concentration set to be higher than the final set-value concentration, and subsequently, the doping gas including the substance having the final set-value concentration is supplied into the container.
    Type: Grant
    Filed: November 18, 2005
    Date of Patent: September 6, 2011
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keisei Morita, Sumio Hoshino
  • Publication number: 20080028798
    Abstract: A method of making a glass is provided in which the time needed for doping a refractive index control substance such as fluorine into a soot glass deposit body can be reduced. The method comprises the steps of: (1) putting a soot glass deposit body in a container; (2) doping a refractive index control substance into the soot glass deposit body by supplying an doping gas into the container, the doping gas containing the substance; and (3) consolidating the soot glass deposit body by heating, wherein the final set-value concentration of the substance is determined beforehand depending on the target refractive index of the glass, and in step (2), the container is supplied with the doping gas including the substance having a concentration set to be higher than the final set-value concentration, and subsequently, the doping gas including the substance having the final set-value concentration is supplied into the container.
    Type: Application
    Filed: November 18, 2005
    Publication date: February 7, 2008
    Inventors: Keisei Morita, Sumio Hoshino
  • Publication number: 20050259932
    Abstract: There is prepared an optical fiber preform 2 whose core region is doped with Ge in such a quantity of dopant that the relative refractive-index difference [Ge] expressed in % with respect to pure SiO2 satisfies the condition [Ge]?0.3%, where upon after being heat drawn with a drawing furnace 11 into an optical fiber 3, the optical fiber 3 is annealed in a heating furnace 21 downstream of the drawing furnace 11 under a condition that the cooling speed is 2000° C./second or less, and the period of annealing time is equal to or longer than the relaxation time. Further, the annealed optical fiber 3 is introduced into a cooling means 31 at an entry temperature of 700° C. or more, and the optical fiber 3 is forcibly cooled by the cooling means 31. As a consequence, there are achieved an optical fiber and a method of fabricating the same capable of fabricating the optical fiber having a reduced Rayleigh scattering loss as well as excellent hydrogen-resisting property with favorably high productivity.
    Type: Application
    Filed: July 10, 2003
    Publication date: November 24, 2005
    Inventors: Katsuya Nagayama, Keisei Morita