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公开(公告)号：US10710924B2
公开(公告)日：2020-07-14
申请号：US15740264
申请日：2016-09-20
Applicant: FUJIKURA LTD.
Inventor： Takayuki Kitamura , Akihito Imase
IPC: C03B37/025 , C03B37/027 , C03B37/03 , G02B6/02
Abstract: An optical fiber production method includes: drawing an optical fiber from an optical fiber preform in a drawing furnace; cooling the optical fiber in an annealing furnace; and delivering the optical fiber into the annealing furnace, and controlling a temperature difference between a temperature of the optical fiber and a fictive temperature of glass forming a core included in the optical fiber to be higher than 20° C. and lower than 100° C.
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公开(公告)号：US20190185365A1
公开(公告)日：2019-06-20
申请号：US16329164
申请日：2017-04-28
Applicant: FUJIKURA LTD.
Inventor： Takayuki Kitamura
IPC: C03B37/027 , G02B6/02
CPC classification number: C03B37/02727 , C03B37/027 , C03B2205/56 , C03B2205/72 , G02B6/02 , G02B6/02395
Abstract: A method for manufacturing an optical fiber includes: drawing an optical fiber from an optical fiber preform in a drawing furnace; and cooling the optical fiber in an annealing furnace. When the optical fiber enters the annealing furnace, a temperature difference between a temperature of the optical fiber and a fictive temperature of glass in a core of the optical fiber is 300° C. or less. The optical fiber is cooled for 0.01 seconds or more in the annealing furnace so that the temperature of the optical fiber becomes 1300° C. or more and 1800° C. or less.
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公开(公告)号：US20180194666A1
公开(公告)日：2018-07-12
申请号：US15740264
申请日：2016-09-20
Applicant: FUJIKURA LTD.
Inventor： Takayuki Kitamura , Akihito Imase
IPC: C03B37/025 , C03B37/03 , G02B6/02
Abstract: An optical fiber production method includes: drawing an optical fiber from an optical fiber preform in a drawing furnace; cooling the optical fiber in an annealing furnace; and delivering the optical fiber into the annealing furnace, and controlling a temperature difference between a temperature of the optical fiber and a fictive temperature of glass forming a core included in the optical fiber to be higher than 20° C. and lower than 100° C.
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14.发明申请公开(公告)号：US20200308043A1
公开(公告)日：2020-10-01
申请号：US16832680
申请日：2020-03-27
Applicant: Fujikura Ltd.
Inventor： Takayuki Kitamura , Nobuo Ozeki , Katsuhiro Takenaga
IPC: C03B37/029 , C03B37/03 , C03B37/023
Abstract: An optical fiber drawing furnace heating element includes a heat generator including: a tubular resistance heating element in which at least a part of an optical fiber preform is disposed in a through-hole; a first portion extending, from a first end portion, over a predetermined section along a longitudinal direction; and a second portion disposed closer to a second end portion than the first portion. The second portion has a wall thickness on a side of the first end portion being equal to or larger than a wall thickness of the first portion. The wall thickness of the second portion increases toward a side of the second end portion from the side of the first end portion.
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公开(公告)号：US20200095158A1
公开(公告)日：2020-03-26
申请号：US16698472
申请日：2019-11-27
Applicant: Fujikura Ltd.
Inventor： Takayuki Kitamura , Akihito Imase
IPC: C03B37/027 , G02B6/02 , C03B37/025
Abstract: An optical fiber production method includes: drawing an optical fiber preform in a drawing furnace; and cooling the optical fiber. The optical fiber is passed through a plurality of annealing furnaces while the optical fiber is cooled. While the optical fiber is cooled, temperatures of the annealing furnaces are set such that the temperature difference is within a range between and including an upper limit and a lower limit of a temperature difference between a temperature of the optical fiber and a fictive temperature of glass constituting a core of the optical fiber at which an increase of a transmission loss of the optical fiber when the fictive temperature of the glass is decreased is less than 0.001 dB/km.
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Patent Agency Ranking
公开(公告)号：US10267984B2
公开(公告)日：2019-04-23
申请号：US15505155
申请日：2016-05-13
Applicant: FUJIKURA LTD.
Inventor： Sho Endo , Takayuki Kitamura
Abstract: The refractive index of the inner core part 11 in a region in contact with the boundary of the outer core part 12 is higher than the refractive index of the outer core part 12. The refractive index of the outer core part 12 is gradually decreased from the inner circumferential side to the outer circumferential side. The refractive index of the inner cladding part 21 is equal to the refractive index of the outermost circumferential part of the outer core part 12 and not greater than the refractive index of the outer cladding part 22.
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公开(公告)号：US20180290914A1
公开(公告)日：2018-10-11
申请号：US15575690
申请日：2016-09-20
Applicant: FUJIKURA LTD.
Inventor： Takayuki Kitamura , Akihito Imase
IPC: C03B37/027 , C03B37/025 , G02B6/02
Abstract: An optical fiber production method includes: drawing an optical fiber from an optical fiber preform in a drawing furnace; and cooling the optical fiber. The optical fiber is passed through a plurality of annealing furnaces while the optical fiber is cooled. Equation (1) is held in a given period during the cooling, where a time constant of relaxation of a structure of glass forming a core included in the optical fiber is defined as τ(T), a temperature of the optical fiber at a point in time during the cooling is defined as T, a fictive temperature of glass forming the core at the point in time is defined as Tf0, and a fictive temperature of glass forming the core after a lapse of time Δt from the point in time is defined as Tf. 20° C.
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公开(公告)号：US10067287B2
公开(公告)日：2018-09-04
申请号：US15514090
申请日：2015-09-24
Applicant: Fujikura Ltd.
Inventor： Sho Endo , Tatsuya Kishi , Takayuki Kitamura
Abstract: An optical fiber includes a core and a cladding surrounding an outer periphery of the core and has a refractive index profile in which a relative refractive index difference with respect to a distance r from a center of the core is represented by Δ(r), where a value of A represented by A=−∫00.22MFD1.31(Δ(r)−Δref(r))dr+∫0.22MFD1.310.44MFD1.31(Δ(r)−Δref(r))dr (Formula 1) is 0.3%·μm or less, where a unit of r is μm, a unit of a relative refractive index difference Δ(r) is %, Δref(r)=−0.064r+0.494, and MFD1.31 is a mode field diameter at a wavelength of 1.31 μm.
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公开(公告)号：US20170336558A1
公开(公告)日：2017-11-23
申请号：US15514090
申请日：2015-09-24
Applicant: Fujikura Ltd.
Inventor： Sho Endo , Tatsuya Kishi , Takayuki Kitamura
CPC classification number: G02B6/02009 , C03B2201/02 , C03B2201/31 , C03B2203/23 , C03B2203/26 , G02B6/0281 , G02B6/03611 , G02B6/03627 , G02B6/03633 , G02B6/0365
Abstract: An optical fiber includes a core and a cladding surrounding an outer periphery of the core and has a refractive index profile in which a relative refractive index difference with respect to a distance r from a center of the core is represented by Δ(r), where a value of A represented by A=−∫00.22MFD1.31(Δ(r)−Δref(r))dr+∫0.22MFD1.310.44MFD1.31(Δ(r)−Δref(r))dr (Formula 1) is 0.3%·μm or less, where a unit of r is μm, a unit of a relative refractive index difference Δ(r) is %, Δref(r)=−0.064r+0.494, and MFD1.31 is a mode field diameter at a wavelength of 1.31 μm.
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公开(公告)号：US20170269294A1
公开(公告)日：2017-09-21
申请号：US15505155
申请日：2016-05-13
Applicant: FUJIKURA LTD.
Inventor： Sho Endo , Takayuki Kitamura
CPC classification number: G02B6/036 , G02B6/02395 , G02B6/0283 , G02B6/0285 , G02B6/03627 , G02B6/0365
Abstract: The refractive index of the inner core part 11 in a region in contact with the boundary of the outer core part 12 is higher than the refractive index of the outer core part 12. The refractive index of the outer core part 12 is gradually decreased from the inner circumferential side to the outer circumferential side. The refractive index of the inner cladding part 21 is equal to the refractive index of the outermost circumferential part of the outer core part 12 and not greater than the refractive index of the outer cladding part 22.
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