Patents by Inventor Munehisa Fujimaki
Munehisa Fujimaki 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).
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Patent number: 9002164Abstract: An optical fiber is provided. The optical fiber has a refractive index profile that includes a central core, an inner cladding layer, a trench layer, and an outer cladding layer. A trench layer is provided with a reduced refractive index. The optical fiber has a large effective area without having an increase of a cutoff wavelength, and exhibits low macrobending loss.Type: GrantFiled: February 28, 2013Date of Patent: April 7, 2015Assignee: Fujikura Ltd.Inventors: Takayuki Kitamura, Akihito Imase, Munehisa Fujimaki
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Publication number: 20140241686Abstract: An optical fiber is provided. The optical fiber has a refractive index profile that includes a central core, an inner cladding layer, a trench layer, and an outer cladding layer. A trench layer is provided with a reduced refractive index. The optical fiber has a large effective area without having an increase of a cutoff wavelength, and exhibits low macrobending loss.Type: ApplicationFiled: February 28, 2013Publication date: August 28, 2014Applicant: FUJIKURA, LTD.Inventors: Takayuki KITAMURA, Akihito IMASE, Munehisa FUJIMAKI
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Patent number: 8268075Abstract: A method of producing a zinc oxide-based semiconductor crystal, including: introducing at least zinc and oxygen on a surface of a substrate; and growing a zinc oxide-based semiconductor crystal on the substrate, wherein a total or partial portion of the zinc is ionized in a vacuum atmosphere of 1×10?4 Torr or less and is introduced to the surface of the substrate to grow the ZnO based semiconductor crystal. As a result, it is possible to provide a method of producing a zinc oxide based semiconductor crystal capable of growing a zinc oxide semiconductor crystal having excellent surface flatness and crystallinity and including an extremely small amount of impurities at a high growth rate.Type: GrantFiled: June 22, 2007Date of Patent: September 18, 2012Assignees: Fujikura Ltd., Chiba UniversityInventors: Koji Omichi, Yoshikazu Kaifuchi, Munehisa Fujimaki, Akihiko Yoshikawa
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Patent number: 7658086Abstract: A drawing method for a bare optical fiber, comprises the steps of: melting an optical fiber preform using a heating device and drawing the bare optical fiber; and naturally cooling down the bare optical fiber or forcibly cooling down the bare optical fiber by a cooling device after the heating and melting step, wherein a temperature history during the drawing the optical fiber preform to obtain the bare optical fiber in the heating device satisfies a relational expression: T??0.01X+12 where a time period when the heated and molten portion of the optical fiber preform heated and molten by the heating device reaches 1800° C. or higher is T (min) and a OH group concentration in a cladding layer of the optical fiber preform is X (wtppm).Type: GrantFiled: May 15, 2006Date of Patent: February 9, 2010Assignee: Fujikura Ltd.Inventors: Kenji Okada, Koichi Harada, Shunichirou Hirafune, Munehisa Fujimaki
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Publication number: 20090260563Abstract: A method of producing a zinc oxide-based semiconductor crystal, including: introducing at least zinc and oxygen on a surface of a substrate; and growing a zinc oxide-based semiconductor crystal on the substrate, wherein a total or partial portion of the zinc is ionized in a vacuum atmosphere of 1×10?4 Torr or less and is introduced to the surface of the substrate to grow the ZnO based semiconductor crystal. As a result, it is possible to provide a method of producing a zinc oxide based semiconductor crystal capable of growing a zinc oxide semiconductor crystal having excellent surface flatness and crystallinity and including an extremely small amount of impurities at a high growth rate.Type: ApplicationFiled: June 22, 2007Publication date: October 22, 2009Applicants: Fujikura Ltd., Chiba UniversityInventors: Koji Omichi, Yoshikazu Kaifuchi, Munehisa Fujimaki, Akihiko Yoshikawa
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Patent number: 7596292Abstract: A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.Type: GrantFiled: November 30, 2005Date of Patent: September 29, 2009Assignee: Fujikura Ltd.Inventors: Takahiro Hamada, Kenji Yamashiro, Munehisa Fujimaki, Koichi Harada, Yukinari Shirako, Hiroyuki Sawano, Shunichirou Hirafune
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Publication number: 20090084141Abstract: 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: ApplicationFiled: December 4, 2008Publication date: April 2, 2009Applicant: FUJIKURA LTD.Inventors: Tomohiro Nunome, Hiroshi Kutami, Manabu Saitou, Kenji Okada, Munehisa Fujimaki, Koichi Harada
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Patent number: 7496261Abstract: A dispersion compensating optical fiber for NZ-DSFs, includes: an uncovered dispersion compensating optical fiber; a double-layered resin coating disposed around the uncovered dispersion compensating optical fiber; and an outer coating layer having a thickness of 3 to 7 ?m, containing silicone in an amount of 1 to 5% by weight, and disposed around the double-layered resin coating. The outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 ?m, an outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 ?m, and the amount of silicone contained in the outer coating layer is determined such that an adhesive property of the outer coating layer is 1 gf/mm or less.Type: GrantFiled: August 15, 2005Date of Patent: February 24, 2009Assignee: Fujikura Ltd.Inventors: Kazuhiko Aikawa, Yutaka Nagasawa, Shogo Shimizu, Takaaki Suzuki, Masakazu Nakayama, Kuniharu Himeno, Ryozo Yamauchi, Keiji Ohashi, Munehisa Fujimaki
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Patent number: 7486863Abstract: A method of treating optical fiber includes at least a first step of creating a reduced-pressure atmosphere in a space which holds the optical fiber, and a second step of introducing to the space a deuterium-containing gas so as to expose the optical fiber to the gas.Type: GrantFiled: June 20, 2006Date of Patent: February 3, 2009Assignee: Fujikura Ltd.Inventors: Takahiro Hamada, Munehisa Fujimaki, Kenji Yamashiro, Koichi Harada, Yukinari Shirako, Hiroyuki Sawano
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Publication number: 20070230863Abstract: An optical/electrical interconnect board includes a base material composing an electrical circuit; a plurality of light receiving/emitting units, each of the units being constituted by a light emitting element and a light receiving element packaged on the base material; and an optical fiber tape that connects the light emitting element to the light receiving element for each of the light receiving/emitting units, the optical fiber tape being formed by bringing together optical wires for the units in a side-by-side manner and coating with a first coating material.Type: ApplicationFiled: March 29, 2007Publication date: October 4, 2007Applicants: FUJIKURA LTD., STANLEY ELECTRIC CO., LTD.Inventors: Takeshi Fukuda, Kentaro Ichii, Yoshihiro Terada, Munehisa Fujimaki, Hiroyuki Oka, Yoshiki Furukawa, Katsumi Inuzuka
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Publication number: 20060233502Abstract: A method of treating optical fiber includes at least a first step of creating a reduced-pressure atmosphere in a space which holds the optical fiber, and a second step of introducing to the space a deuterium-containing gas so as to expose the optical fiber to the gas.Type: ApplicationFiled: June 20, 2006Publication date: October 19, 2006Inventors: Takahiro Hamada, Munehisa Fujimaki, Kenji Yamashiro, Koichi Harada, Yukinari Shirako, Hiroyuki Sawano
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Publication number: 20060204193Abstract: A drawing method for a bare optical fiber, comprises the steps of: melting an optical fiber preform using a heating device and drawing the bare optical fiber; and naturally cooling down the bare optical fiber or forcibly cooling down the bare optical fiber by a cooling device after the heating and melting step, wherein a temperature history during the drawing the optical fiber preform to obtain the bare optical fiber in the heating device satisfies a relational expression: T??0.01X+12 where a time period when the heated and molten portion of the optical fiber preform heated and molten by the heating device reaches 1800° C. or higher is T (min) and a OH group concentration in a cladding layer of the optical fiber preform is X (wtppm).Type: ApplicationFiled: May 15, 2006Publication date: September 14, 2006Inventors: Kenji Okada, Koichi Harada, Shunichirou Hirafune, Munehisa Fujimaki
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Publication number: 20060127018Abstract: A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.Type: ApplicationFiled: November 30, 2005Publication date: June 15, 2006Inventors: Takahiro Hamada, Kenji Yamashiro, Munehisa Fujimaki, Koichi Harada, Yukinari Shirako, Hiroyuki Sawano, Shunichirou Hirafune
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Patent number: 7041334Abstract: An optical fiber coating die is made such that an interfacial shear rate of the optical fiber to the resin coat is calculated in accordance with a pressure value of resin inside a coating cup, and the interfacial shear rate is in a range of ?1.5×105 to 0 sec?1. Also, an optical fiber drawing die is made such that the interfacial shear rate of the optical fiber to the resin coat is calculated in accordance with a diameter of a coating resin, and the interfacial shear rate is in a range of range of ?3×105 to 2×105 sec?1. By doing this, an optical fiber drawing die which can be used in an optical fiber drawing method so as to realize stable resin coating operation even in high-speed drawing operation and high productivity can be realized.Type: GrantFiled: December 6, 2002Date of Patent: May 9, 2006Assignee: Fujikura Ltd.Inventors: Munehisa Fujimaki, Takahiro Hamada, Koichi Harada
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Publication number: 20060062534Abstract: A dispersion compensating optical fiber for NZ-DSFs, includes: an uncovered dispersion compensating optical fiber; a double-layered resin coating disposed around the uncovered dispersion compensating optical fiber; and an outer coating layer having a thickness of 3 to 7 ?m, containing silicone in an amount of 1 to 5% by weight, and disposed around the double-layered resin coating. The outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 ?m, an outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 ?m, and the amount of silicone contained in the outer coating layer is determined such that an adhesive property of the outer coating layer is 1 gf/mm or less.Type: ApplicationFiled: August 15, 2005Publication date: March 23, 2006Inventors: Kazuhiko Aikawa, Yutaka Nagasawa, Shogo Shimizu, Takaaki Suzuki, Masakazu Nakayama, Kuniharu Himeno, Ryozo Yamauchi, Keiji Ohashi, Munehisa Fujimaki
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Publication number: 20060016393Abstract: An optical fiber coating die is made such that an interfacial shear rate of the optical fiber to the resin coat is calculated in accordance with a pressure value of resin inside a coating cup, and the interfacial shear rate is in a range of ?1.5×105 to 0 sec?1. Also, an optical fiber drawing die is made such that the interfacial shear rate of the optical fiber to the resin coat is calculated in accordance with a diameter of a coating resin, and the interfacial shear rate is in a range of range of ?3×105 to 2×105 sec?1. By doing this, an optical fiber drawing die which can be used in an optical fiber drawing method so as to realize stable resin coating operation even in high-speed drawing operation and high productivity can be realized.Type: ApplicationFiled: July 22, 2005Publication date: January 26, 2006Inventors: Munehisa Fujimaki, Takahiro Hamada, Koichi Harada
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Patent number: 6965719Abstract: A dispersion compensating optical fiber includes an uncovered dispersion compensating optical fiber containing a core and a cladding, and a resin coating which is disposed around the uncovered dispersion compensating optical fiber, wherein the resin coating has an adhesive property of 10 g/mm or less, and which includes an outer coating layer which is formed to have a thickness of 3 ?m or more, and the outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 ?m, and the outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 ?m.Type: GrantFiled: March 21, 2002Date of Patent: November 15, 2005Assignee: Fujikura Ltd.Inventors: Kazuhiko Aikawa, Yutaka Nagasawa, Shogo Shimizu, Takaaki Suzuki, Masakazu Nakayama, Kuniharu Himeno, Ryozo Yamauchi, Keiji Ohashi, Munehisa Fujimaki
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Patent number: 6789399Abstract: When an optical fiber 3 is formed by drawing a preform 1, twisting is generated in the optical fiber 3. An outer diameter of the optical fiber 3 is continuously measured along a longitudinal direction of the optical fiber 3 from two different directions in a plane perpendicular to the advancing direction of the optical fiber 3 by a device for measuring twisting 4, thus twisting of the optical fiber 3 is measured.Type: GrantFiled: January 5, 2001Date of Patent: September 14, 2004Assignee: Fujikura Ltd.Inventors: Munehisa Fujimaki, Koichi Takahashi
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Patent number: 6768854Abstract: A manufacturing method and apparatus for manufacturing a coated optical fiber which has a superior surface smoothness of a resin coating and which can be coated with a colored ink with high coating performance. In the method including the steps of making a coated optical fiber by forming an outer coating layer around a bare optical fiber; and winding the coated optical fiber via pulleys by a take-up, the surface roughness of each solid body which the outer layer of the running coated optical fiber contacts is 0.8 &mgr;m or less. When the temperature of the outer coating layer is a room temperature or the Young's modulus of the outer coating layer is higher than 500 MPa, the surface roughness of each solid body, which the outer layer of the coated optical fiber contacts during drawing or rewinding, is 1.2 &mgr;m or less.Type: GrantFiled: October 25, 2002Date of Patent: July 27, 2004Assignee: Fujikura Ltd.Inventors: Koji Tsuruśaki, Koichi Harada, Munehisa Fujimaki
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Publication number: 20040031291Abstract: The present invention provides a drawing method for optical fiber, which is capable of reducing attenuation at 1.55 um due to Rayleigh scattering, even if the drawing speed is high. The reduction of the attenuation of the optical fiber 3 is realized by conducting a preliminary cooling in a first cooling zone 4, which has a low convection heat transfer coefficient, for reducing the temperature of the as-drawn optical fiber just before entering into a second cooling zone 5. The optical fiber is obtained after being cooled in the second cooling zone 5, which has a higher convection heat transfer coefficient.Type: ApplicationFiled: May 20, 2003Publication date: February 19, 2004Inventors: Takahiro Hamada, Munehisa Fujimaki