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US20040028362A1 - Optical fiber preform, method for manufacturing thereof, and optical fiber obtained by drawing thereof - Google Patents

Optical fiber preform, method for manufacturing thereof, and optical fiber obtained by drawing thereof Download PDF

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Publication number
US20040028362A1
US20040028362A1 US10/634,779 US63477903A US2004028362A1 US 20040028362 A1 US20040028362 A1 US 20040028362A1 US 63477903 A US63477903 A US 63477903A US 2004028362 A1 US2004028362 A1 US 2004028362A1
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US
United States
Prior art keywords
clad layer
optical fiber
viscosity
preform
rod
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/634,779
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English (en)
Inventor
Tetsuya Otosaka
Dai Inoue
Hiroshi Oyamada
Jun Abe
Hideo Hirasawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shin Etsu Chemical Co Ltd
Original Assignee
Shin Etsu Chemical Co Ltd
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Filing date
Publication date
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Assigned to SHIN-ETSU CHEMICAL CO., LTD. reassignment SHIN-ETSU CHEMICAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ABE, JUN, HIRASAWA, HIDEO, OYAMADA, HIROSHI, INOUE, DAI, OTOSAKA, TETSUYA
Publication of US20040028362A1 publication Critical patent/US20040028362A1/en
Priority to US11/133,193 priority Critical patent/US7752869B2/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C13/00—Fibre or filament compositions
    • C03C13/04—Fibre optics, e.g. core and clad fibre compositions
    • C03C13/045—Silica-containing oxide glass compositions
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01211—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/0128—Manufacture of preforms for drawing fibres or filaments starting from pulverulent glass
    • C03B37/01291—Manufacture of preforms for drawing fibres or filaments starting from pulverulent glass by progressive melting, e.g. melting glass powder during delivery to and adhering the so-formed melt to a target or preform, e.g. the Plasma Oxidation Deposition [POD] process
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/036—Optical fibres with cladding with or without a coating core or cladding comprising multiple layers
    • G02B6/03694—Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/08—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant
    • C03B2201/12—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant doped with fluorine
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/20—Doped silica-based glasses doped with non-metals other than boron or fluorine
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/20—Doped silica-based glasses doped with non-metals other than boron or fluorine
    • C03B2201/28—Doped silica-based glasses doped with non-metals other than boron or fluorine doped with phosphorus
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
    • C03B2201/31—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with germanium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2203/00—Fibre product details, e.g. structure, shape
    • C03B2203/10—Internal structure or shape details
    • C03B2203/22—Radial profile of refractive index, composition or softening point
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2203/00—Fibre product details, e.g. structure, shape
    • C03B2203/10—Internal structure or shape details
    • C03B2203/22—Radial profile of refractive index, composition or softening point
    • C03B2203/23—Double or multiple optical cladding profiles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Definitions

  • the present invention relates to an optical fiber preform with a small transmission loss of light at wavelength of 1385 nm and small rise of the transmission loss caused by a hydroxy (OH) group in case of being exposed to hydrogen atmosphere, a method for manufacturing the optical fiber preform, and an optical fiber obtained by drawing the optical fiber preform.
  • FIG. 1 shows an example of the configuration of a conventional optical fiber preform sintering apparatus 100 .
  • the sintering apparatus 100 has a container 14 , a heater 22 , a gas introduction pipe 24 , and a drive source 16 .
  • the container 14 is made from silica glass.
  • a heater 22 is arranged around the container 14 to heat the container 14 .
  • the gas introduction pipe 24 is connected to the bottom part of the container 14 , and the mixed gas, which contains inert gas such as helium (He) gas and dehydration-reaction-gas such as chlorhine (Cl 2 ) gas, is introduced into the container 14 through the gas introduction pipe 24 .
  • inert gas such as helium (He) gas
  • dehydration-reaction-gas such as chlorhine (Cl 2 ) gas
  • An exhaust pipe 20 is connected to the top part of the container 14 , and the mixed gas which travels through the container 14 from the bottom part of the container 14 is discharged from the exhaust pipe 20 .
  • the drive source 16 is provided in the upper part of the sintering apparatus 100 .
  • the drive source 16 is connected to a core rod 10 .
  • the optical fiber preform 12 is formed around the circumference of the core rod 10 by such as VAD method before the dehydration process.
  • the drive source 16 inserts the preform 12 into the container 14 by descending the core rod 10 into the container 14 .
  • the container 14 is filled with the atmosphere of the mixed gas, which flowed from the gas introduction pipe 24 , and the circumference of the container 14 is heated by the heater 22 . Therefore, the preform 12 inserted into the container 14 is heated under a mixed gas atmosphere to be dehydrated and sintered.
  • FIG. 2 shows relationship between a transmission loss and wavelength in a conventional general single mode optical fiber.
  • Wavelength of light used in communication is mainly about 1300 nm or about 1550 nm because an inexpensive semiconductor laser can be used.
  • WDM Wide length Division Multiplexing
  • the transmission loss in a general optical fiber rises sharply in wavelength of about 1385 nm.
  • the regenerator for amplifying and regenerating light needs to be added for a long distance transmission, which results in that cost of the whole transmission or communication system rises.
  • a difference between a peak value of the transmission loss at wavelength of about 1385 nm and a value of the transmission loss in a case of decreasing gradually as shown by a broken line is defined as an OH peak hereinafter.
  • the OH peak shown in FIG. 2 is about 0.06 dB/km.
  • the sharp rise or abrupt increase of the transmission loss at wavelength of about 1385 nm, i.e. the OH peak is caused by vibration of the OH group contained in the optical fiber and absorbing light of that wavelength.
  • FIG. 3 shows a rise of 0.1 dB/km of the OH peak at wavelength of about 1385 nm.
  • the OH peak at wavelength of about 1240 nm is caused by hydrogen diffusing in the optical fiber.
  • the OH peak disappears if the optical fiber is exposed to atmospheric air for a while and hydrogen is removed from the optical fiber.
  • the rise of the OH peak at wavelength of about 1385 nm is irreversible and does not decrease. Therefore, the defect that causes the rise of the OH peak in the optical fiber needs to be reduced sufficiently.
  • the preform of the present invention is that the maximum value V 0 [log(poise)] of radial viscosity distribution of the optical fiber is greater than 7.608[log(poise)] at the T s .
  • the maximum value V 0 [log(poise)] of viscosity distribution may be greater than 7.908[log(poise)].
  • the prefrom comprises a multi layer structure of which an outside area of the clad has more than two layers and has a high viscosity clad layer of which at least at one temperature viscosity is greater than viscosity of the inner clad layer of the most inside area in the outside area at the temperature T s , among the clad layers outside the inner clad layer.
  • an outside low viscosity clad layer of which viscosity is smaller than V 0 at the temperature T s is the most outside of the clad.
  • viscosity of surface of the preform at the temperature T s is preferably lower than V 0 .
  • the clad of the outside area may be comprised of two layers, that is, an inner clad layer and a high viscosity clad layer.
  • a synthetic quartz glass may be used as the inner clad layer, and a quartz glass, for example such as a native quartz or a crystallization synthetic quartz glass, containing crystal type silica may be used as the high viscosity clad layer.
  • the preform may be manufactured by using the synthetic quartz glass having the lower viscosity than a pure synthetic quartz glass by doping at least with one dopant among chlorine, germanium, fluorine, and phosphorus as the inner clad layer and using the synthetic quartz glass having higher viscosity than the inner clad layer by not doping or doping with small amount of dopant as the high viscosity clad layer.
  • a portion containing at least the core and the inner clad layer may be formed by VAD method, OVD method, MCVD method, and PCVD method, or by appropriate combination of them.
  • a method for manufacturing the preform includes steps of covering circumference of the rod at least the core and the inner clad layer with a tube containing at least the high viscosity clad layer, and unifying the rod and the tube by heating and contracting the tube or by heating glass grain while depositing the glass grain which forms the high viscosity clad layer.
  • plasma flame is preferably used at this heating.
  • the preform may be manufactured by forming a porous preform by depositing glass particles generated by a flame hydrolysis of a glass crude material containing silicon on the circumference of the rod comprising at least the core and the inner clad layer, and forming the high viscosity clad layer by vitrifying the porous preform at temperature between 1400 and 1600° C. after dehydrating the porous preform in atmosphere containing dehydration gas at temperature range between 900 and 1200° C. In this case, chlorine gas is used as the dehydration gas.
  • the method for manufacturing preform comprises covering circumference of the rod comprising at least the core, the inner clad layer, and the high viscosity clad layer with the tube containing at least the outside low viscosity clad layer, and unifying the rod and the tube by heating and contracting the tube.
  • the preform may be manufactured by forming the outside low viscosity clad layer by depositing glass particles generated by flame hydrolysis of glass crude material containing silicon on the circumference of the rod.
  • the method for manufacturing the preform may comprise covering circumference of the rod comprising at least the core and the inner clad layer with the tube containing the high viscosity clad layer, and unifying the rod and the tube by heating and contracting the tube, while forming the outside low viscosity clad layer by depositing glass particles generated by flame hydrolysis of glass crude material containing silicon.
  • the method may comprise covering circumference of the rod comprising at least the core and the inner clad layer with the tube containing at least the high viscosity clad layer and the outside low viscosity clad layer, and unifying the rod and the tube by heating and contracting the tube.
  • optical fiber of which the transmission loss at wavelength of 1385 nm is equal to or less than 0.35 dB/km, preferably equal to or less than 0.30 dB/km, is obtained by heating and drawing the above-mentioned preform.
  • the transmission loss of the optical fiber at wavelength of 1385 nm is equal to or less than 0.35 dB/km in case that the fiber is exposed to atmosphere containing 1% hydrogen for four days, and does not substantially change compared with the transmission loss at wavelength of 1385 nm before exposed to the atmosphere.
  • FIG. 1 is a partially cut-out view showing an example of the conventional configuration of an optical fiber preform sintering apparatus.
  • FIG. 2 is a graphic chart showing relationship between the transmission loss and wavelength in a general single mode optical fiber.
  • FIG. 3 is a graphic chart showing relationship between the transmission loss and wavelength of the fiber being exposed to hydrogen atmosphere.
  • FIG. 4 shows an example of a preform 200 manufactured by the sintering apparatus to which the invention is applied.
  • FIG. 5 is a graphic chart showing relationship between difference of relative index of refraction of the preform and radial viscosity distribution at the temperature T s in examples 1-7 of the present invention and a comparative example 4.
  • FIG. 6 is a graphic chart showing relationship between difference of relative index of refraction and radial viscosity distribution at the temperature T s in the preform as examples 1-3.
  • FIG. 7 is a graphic chart showing relationship between difference of relative index of refraction of the preform and radial viscosity distribution at the temperature T s as an example 8 of the present invention.
  • FIG. 4 shows an example of a preform 200 manufactured by the sintering apparatus 100 shown in FIG. 1.
  • a preform 200 has a cylindrical core 10 , made from quartz doped with germanium, and a first, inner clad 32 , made from quartz, formed around the outside surface of the core 10 .
  • a second, outer clad 34 may be formed around the outside surface of the preform 200 to increase the thickness of the clad 32 .
  • the content of the OH group in the preform 200 is substantially 0.8 ppb or less.
  • the amount of projection of the OH peak in the curve that shows the transmission loss of the light of the optical fiber, which is obtained by drawing the preform 200 is substantially 0.05 dB/km or less. Therefore, the optical fiber obtained from the preform 200 can be used for light transmission in the wavelength band from 1300 nm to 1600 nm.
  • the rise of the transmission loss (OH peak) at wavelength of 1385 nm is suppressed by controlling radial viscosity distribution around softening temperature of the preform.
  • the preform of the present invention is that the maximum value V 0 [log(poise)] of radial viscosity distribution of the optical fiber is greater than 7.608[log(poise)] at the temperature T s , defined as temperature at which the maximum value V 0 [log(poise)] of radial viscosity distribution of the optical fiber in an inside area is 7.608[log(poise)] in an inside and an outside area equivalent to two times of mode field diameter, in which light at wavelength of 1385 nm propagates in the optical fiber obtained by drawing the preform.
  • the optical fiber obtained by drawing the preform of the present invention has a superior characteristic that rise of the OH peak is suppressed remarkably without depending on the condition of the drawing process.
  • This temperature T s is about 1600° C. in the case of a normal single mode fiber in which quartz glass doped with germanium (Ge), is used as a core.
  • the above-mentioned viscosity distribution is achieved by having more than two layers as the clad in the outside area, lowering viscosity of the inner clad layer of the most inside layer in the outside area, and forming a high viscosity layer by heightening viscosity of at least one of the other clad layers.
  • the fiber normally has two layers including an inner clad layer of low viscosity and a high viscosity clad layer, it may have three layers as mentioned below according to viscosity and thickness of the high viscosity clad layer.
  • maximum value V 0 [log(poise)] of radial viscosity distribution outside the inside area is preferably equal to or more than 7.90[log(poise)] at the temperature T s . at which the maximum value of radial viscosity distribution is 7.608[log(poise)], so that the desired effect of the invention can be realized.
  • outer diameter of the inner clad is preferably small to suppress rise of the OH peak due to hydrogen
  • a glass used for the high viscosity clad layer is material of which the possibility of increasing the transmission loss remarkably is high like a native quartz glass
  • the outer diameter is sufficiently large (about six times of the mode field diameter)
  • the initial loss may be large.
  • an upper limit of V 0 is about 9.0.
  • an upper limit of V 0 can be larger than 9.0, and influences such as the transmission loss caused by doping, can not be defined sweepingly because the influence largely depends on the composition.
  • Viscosity can be distributed in radial direction of the preform by changing quality of glass material composing the inner clad layer and the high viscosity clad layer.
  • the synthetic quartz glass used for the preform for the conventional optical fiber includes amorphous structure manufactured by oxidizing or hydrolyzing by flame glass crude material gas such as silicon tetrachloride.
  • amorphous structure manufactured by oxidizing or hydrolyzing by flame glass crude material gas such as silicon tetrachloride.
  • the native quartz glass manufactured by heating and fusing the native quartz there are many microcrystals of cristobalite type helix originating from the nature of quartz and quartz type helix that cristobalite type is dislocated in the amorphous structure. Because these microcrystals suppress flow of glass, the native quartz glass has higher viscosity than the synthetic quartz glass.
  • a crystallization quartz glass manufactured by depositing microcrystal in the synthetic quartz glass has higher viscosity than a conventional synthetic quartz glass.
  • viscosity of the crystallization quartz glass can be lower easily by doping the synthetic quartz glass with many kind of dopant.
  • the dopant such as chlorine, germanium, fluorine, phosphorus, and the like does not cause so large rise of the loss at wavelength range between 1300 to 1600 nm which is normally used for the optical fiber communication, so these dopant are preferably used.
  • the synthetic quartz glass or the synthetic quartz glass doped with a dopant to lower viscosity is preferably used for the inner clad layer, and the inner clad layer can be formed as an extension of clad portion of the inside area.
  • the first method covering outside of a rod containing the core portion and the inner clad layer with the high viscosity clad layer having high viscosity comprises unifying the rod and a tube by placing the rod in the tube containing the high viscosity clad layer and contracting the rod by heating form outside.
  • oxyhydrogen flame, electric furnace, plasma torch, or the like can be used as a heating source.
  • the second method comprises unifying the rod and glass grain by heating while depositing on the circumference of the above-mentioned rod by scattering the glass grain composing the high viscosity clad layer.
  • plasma torch is preferably used as the heating source.
  • the third method covering the rod with the high viscosity clad layer is OVD method that includes forming the porous preform by depositing glass particles manufactured by flame hydrolysis of the glass crude material containing silicon on the circumference of the above-mentioned rod, and a dehydrating porous preform at the temperature range between 900 and 120° C. in the atmosphere containing dehydration gas such as chlorine or the like, and then forming the high viscosity clad layer by vitrifying in the atmosphere at the temperature between 1400 and 1600° C.
  • the inner clad layer needs to be doped with dopant to lower its viscosity.
  • the first method covering outside of the high viscosity clad layer with the outside low viscosity clad layer includes covering the circumference of the rod with the tube containing at least the outside low viscosity clad layer, and unifying the rod and the tube by heating and contracting the tube.
  • the second method covering outside of the high viscosity clad layer with the outside low viscosity clad layer includes depositing glass particles manufactured by flame hydrolysis of glass crude material containing silicon on the circumference of the rod containing the high viscosity clad layer.
  • the first method covering outside of the inner clad layer with the high viscosity clad layer and the outside low viscosity clad layer comprises covering the circumference of the rod comprising at least the core and the inner clad layer with the tube containing the high viscosity clad layer, and then covering the tube with the outside low viscosity clad layer by depositing glass particles manufactured by flame hydrolysis of glass crude material containing silicon, while unifying the rod and the tube by heating and contracting the tube.
  • the first method covering outside of the inner clad layer with the high viscosity clad layer and the outside low viscosity clad layer comprises covering the circumference of the rod comprising at least the core and the inner clad layer with the tube containing at least the high viscosity clad layer and the outside low viscosity clad layer, and unifying the rod and the tube by heating and contracting the tube.
  • An step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of the core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the preform having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 100 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 12.5 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 7.9[log(poise)].
  • Rise of the OH peak of 0.03 dB/km is measured, after this optical fiber is exposed to atmosphere containing 1% hydrogen for four days.
  • FIG. 5 to 7 are graphs showing relationships of differences of relative index of refraction and radial viscosity distribution at the temperature T s of the preform, of which upper row is relationship of difference of relative index of refraction and structure, and the lower is relationship of viscosity and optical fiber equivalent radius.
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of the core in the inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the preform having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 90 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 17.5 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 7.98[log(poise)].
  • Rise of the OH peak of 0.014 dB/km is measured, after this optical fiber is exposed to atmosphere containing 1% hydrogen for four days.
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of the core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the preform having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 80 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 22.5 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 7.98[log(poise)].
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of the core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the preform having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 35 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 45 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 7.98[log(poise)].
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the pre-form having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 80 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 22.5 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 8.5[log(poise)].
  • the step index type single mode optical fiber as shown in FIG. 6, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by drawing a normal pre-form that the whole of clad is formed with the same material as clad of periphery of the core at drawing speed of 800 m/min and drawing tension of 1.4N.
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the pre-form having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 500 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 100 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 12.5 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 7.98[log(poise)].
  • Rise of the OH peak of 0.011 dB/km is measured, after this optical fiber is exposed to atmosphere containing 1% hydrogen for four days.
  • the step index type single mode optical fiber as shown in FIG. 6, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by drawing the normal optical fiber pre-form that the whole of clad is formed with the same material as clad of periphery of the core at drawing speed of 500 m/min and drawing tension of 1.4N.
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the pre-form having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 150 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 100 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 12.5 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s . is 7.98[log(poise)].
  • the step index type single mode optical fiber as shown in FIG. 6, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter) at wavelength of 1385 nm is 10 ⁇ m, is manufactured by drawing the normal optical fiber pre-form that the whole of clad is formed with the same material as clad of periphery of the core at drawing speed of 150 m/min and drawing tension of 1.4N.
  • the step index type single mode optical fiber as shown in FIG. 7, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the pre-form having three layers of the inner clad layer, the high viscosity clad layer, and the outside low viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 105 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 7 ⁇ m in terms of optical fiber
  • thickness of the outside low viscosity clad layer is 3 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 8.58[log(poise)]
  • viscosity V t of the outside low viscosity clad layer at the temperature T s is 7.68 [log(poise)].
  • the step index type single mode optical fiber as shown in FIG. 5, of which outer diameter is 125 ⁇ m, difference of relative index of refraction is 0.34%, mode field diameter at wavelength of 1385 nm is 10 ⁇ m, is manufactured by forming clad of periphery of core in inside area with glass which has the same composition as the inner clad layer in outside area, and drawing the pre-form having two layers of the inner clad layer and the high viscosity clad layer in outside area at drawing speed of 800 m/min and drawing tension of 1.4N.
  • an outer diameter of the inner clad layer is 111 ⁇ m in terms of optical fiber diameter
  • thickness of the high viscosity clad layer is 7 ⁇ m in terms of optical fiber
  • viscosity V 0 of the high viscosity clad layer at the temperature T s is 8.58[log(poise)].
  • the optical fiber breaks, and many breakage inside of remaining optical fiber are also recognized. Because the outside low viscosity clad layer is not formed on the most outside of the clad, the optical fiber is broken.

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EP2539288A1 (en) * 2010-02-26 2013-01-02 Corning Incorporated Optical fiber with increased mechanical strength
US20160299289A1 (en) * 2015-04-07 2016-10-13 Corning Incorporated Low attenuation fiber with stress relieving layer and a method of making such
US20220267193A1 (en) * 2019-07-17 2022-08-25 Heraeus Quarzglas Gmbh & Co. Kg Methods for producing a hollow-core fiber and for producing a preform for a hollow-core fiber

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FR2863606B1 (fr) * 2003-12-15 2007-06-01 Cit Alcatel Procede de realisation d'une preforme a fibre optique, preforme a fibre optique et fibre optique associees
DK2008977T3 (da) * 2006-06-26 2013-11-04 Sumitomo Electric Industries Fremgangsmåde til fremstilling af optisk fiber og dens præform
DE102007003889B3 (de) * 2007-01-19 2008-09-11 Heraeus Quarzglas Gmbh & Co. Kg Quarzglasrohr als Halbzeug für die Vorform- und Faserherstellung, dessen Verwendung sowie Verfahren zur Herstellung des Quarzglasrohres
JP4926164B2 (ja) * 2008-12-26 2012-05-09 信越化学工業株式会社 高周波誘導熱プラズマトーチを用いた光ファイバプリフォームの製造方法及び装置
US8065893B2 (en) * 2009-07-10 2011-11-29 Dau Wu Process, apparatus, and material for making silicon germanium core fiber
DE102011118268A1 (de) 2011-05-27 2012-11-29 J-Plasma Gmbh Verfahren zur Herstellung eines Halbzeugs zur Fertigung einer biegeoptimierten Lichtleitfaser
US9108876B2 (en) * 2011-11-30 2015-08-18 Corning Incorporated Pressed, multilayered silica soot preforms for the manufacture of single sinter step, complex refractive index profile optical fiber
US9290405B2 (en) 2013-09-06 2016-03-22 Corning Incorporated Method of making updoped cladding by using silicon tertrachloride as the dopant
US9658395B2 (en) * 2014-10-21 2017-05-23 Ofs Fitel, Llc Low loss optical fiber and method of making the same
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WO2020157766A1 (en) * 2019-01-29 2020-08-06 Sterlite Technologies Limited Optimized core particles for optical fiber preform and optical fiber preform thereof
EP3766848B1 (de) * 2019-07-17 2022-03-02 Heraeus Quarzglas GmbH & Co. KG Verfahren zur herstellung einer hohlkernfaser und zur herstellung einer vorform für eine hohlkernfaser

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US20070165630A1 (en) * 2006-01-13 2007-07-19 Nokia Corporation Optimization of PDP context usage
US7911943B2 (en) * 2006-01-13 2011-03-22 Nokia Corporation Optimization of PDP context usage
EP2539288A1 (en) * 2010-02-26 2013-01-02 Corning Incorporated Optical fiber with increased mechanical strength
US20160299289A1 (en) * 2015-04-07 2016-10-13 Corning Incorporated Low attenuation fiber with stress relieving layer and a method of making such
US9772445B2 (en) * 2015-04-07 2017-09-26 Corning Incorporated Low attenuation fiber with stress relieving layer and a method of making such
US9778413B2 (en) * 2015-04-07 2017-10-03 Corning Incorporated Low attenuation fiber with stress relieving layer and a method of making such
US20220267193A1 (en) * 2019-07-17 2022-08-25 Heraeus Quarzglas Gmbh & Co. Kg Methods for producing a hollow-core fiber and for producing a preform for a hollow-core fiber

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