WO2012111436A1 - Procédé de fabrication de fibres optiques - Google Patents

Procédé de fabrication de fibres optiques Download PDF

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Publication number
WO2012111436A1
WO2012111436A1 PCT/JP2012/052303 JP2012052303W WO2012111436A1 WO 2012111436 A1 WO2012111436 A1 WO 2012111436A1 JP 2012052303 W JP2012052303 W JP 2012052303W WO 2012111436 A1 WO2012111436 A1 WO 2012111436A1
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WIPO (PCT)
Prior art keywords
optical fiber
base material
glass base
hole
ratio
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PCT/JP2012/052303
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English (en)
Japanese (ja)
Inventor
下高原　巌
治巳 稲葉
熊野　尚美
杉崎　隆一
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古河電気工業株式会社
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Publication of WO2012111436A1 publication Critical patent/WO2012111436A1/fr

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    • 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
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
    • C03B37/02781—Hollow fibres, e.g. holey fibres
    • 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
    • C03B2203/14—Non-solid, i.e. hollow products, e.g. hollow clad or with core-clad interface
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2203/00—Fibre product details, e.g. structure, shape
    • C03B2203/42—Photonic crystal fibres, e.g. fibres using the photonic bandgap PBG effect, microstructured or holey optical fibres
    • 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
    • G02B6/02295—Microstructured optical fibre
    • G02B6/02314—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes
    • G02B6/02342—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes characterised by cladding features, i.e. light confining region
    • G02B6/02357—Property of longitudinal structures or background material varies radially and/or azimuthally in the cladding, e.g. size, spacing, periodicity, shape, refractive index, graded index, quasiperiodic, quasicrystals

Definitions

  • the present invention relates to a method for manufacturing an optical fiber having a plurality of holes extending along a longitudinal axis.
  • a so-called holey fiber (Holey Fiber: HF) or photonic crystal fiber (Photonic Crystal Fiber: PCF), or a photonic band gap is used.
  • fiber Photonic BandGap Fiber: PBGF
  • hole assist fiber Hole Assisted Fiber: HAF
  • HF is an optical fiber of a type in which holes are regularly arranged in the cladding around the core to lower the average refractive index of the cladding and realize light confinement using the principle of total reflection.
  • PBGF forms photonic band gaps by arranging vacancies in the cladding part so as to form a photonic crystal, and introduces a core part as a crystal defect therein to realize light confinement.
  • a core part may be formed of a void
  • HAF is formed from a solid core portion doped with germanium (Ge) or the like and a cladding portion, as in a normal solid optical fiber, and light confinement is realized mainly by the principle of total reflection.
  • This is an optical fiber of a type in which holes are further provided in the cladding part to lower the average refractive index of the cladding part and to improve the light confinement characteristics in the core part.
  • HAF can improve the light confinement characteristics by providing holes near the core, bending loss can be significantly reduced.
  • HAF not only the fundamental mode but also higher-order mode light is easily confined, so that it is easy to make a multimode.
  • HAF in order to realize single mode propagation by confining only fundamental mode light and to reduce bending loss of single mode propagation, optimization of hole diameter, number of holes, core-hole distance, etc. Will be needed. Recently, from these viewpoints, a design in which the hole diameter is reduced and the number of holes is increased to about 10 has been proposed (see Non-Patent Document 1).
  • the present invention has been made in view of the above, and an object thereof is to provide an optical fiber manufacturing method capable of realizing a reduction in manufacturing cost.
  • an optical fiber manufacturing method is a glass base material having a plurality of holes extending along a longitudinal axis.
  • the ratio with the diameter is the second ratio
  • the pressure in the at least one hole of the glass base material is such that the ratio between the second ratio and the first ratio is less than 1.0.
  • the line drawing is performed by adjusting.
  • the optical fiber manufacturing method according to the present invention is characterized in that, in the above invention, the ratio of the second ratio to the first ratio is 0.5 or more.
  • the optical fiber manufacturing method according to the present invention is characterized in that, in the above invention, the plurality of pores of the glass base material are pressurized with different pressures.
  • the optical fiber manufacturing method according to the present invention is characterized in that, in the above invention, the diameter of the plurality of holes in the glass base material is 3 mm or more.
  • FIG. 1 is a schematic cross-sectional view of an optical fiber manufactured by the manufacturing method according to the first embodiment.
  • FIG. 2 is a schematic perspective view of a glass preform for manufacturing the optical fiber shown in FIG.
  • FIG. 3 is a diagram for explaining a drawing process.
  • FIG. 4 is a diagram showing the relationship between the dimensionless in-hole pressurization amount and the ratio (X / Y).
  • FIG. 5 is a diagram showing the relationship between the ratio (X / Y) and the dimensionless pore diameter variation.
  • FIG. 6 is a schematic cross-sectional view of an optical fiber manufactured by the manufacturing method according to the second embodiment.
  • FIG. 7 is a schematic perspective view of a glass preform for manufacturing the optical fiber shown in FIG.
  • FIG. 8 is a schematic diagram of a pressure mechanism used in the manufacturing method according to the second embodiment.
  • FIG. 9 is a schematic cross-sectional view of another optical fiber that can be manufactured by the manufacturing method according to the second embodiment.
  • the cutoff wavelength is ITU-T (International Telecommunication Union) This refers to the fiber cutoff wavelength defined in 650.1.
  • ITU-T G.A. 650.1 and G.I. It shall follow the definition and measurement method in 650.2.
  • FIG. 1 is a schematic cross-sectional view of an optical fiber manufactured by the manufacturing method according to Embodiment 1 of the present invention.
  • the optical fiber 1 is a HAF and includes a core portion 1a and a clad portion 1b formed on the outer periphery of the core portion 1a.
  • the core portion 1a is made of quartz glass to which a dopant for increasing the refractive index such as germanium (Ge) is added.
  • the clad part 1b is made of quartz glass having a lower refractive index than that of the core part 1a, for example, pure silica glass not containing a dopant for adjusting the refractive index.
  • the cross-sectional refractive index distribution shape around the core portion 1a is a rectangle (step index), a pseudo rectangle (pseudo step index) with a skirt at the boundary with the cladding portion 1b, and a Gaussian distribution shape (refractive index distribution coefficient ⁇ is approximately 2. Graded index) may be used.
  • the clad portion 1b has ten holes 1c formed so as to surround the core portion 1a and extending along the longitudinal axis.
  • Two holes 1c are formed when the center point of the core portion 1a is connected to each of the center points of any two adjacent holes 1c in a cross section perpendicular to the longitudinal direction of the optical fiber 1. Are formed at positions where the angles (center angles) formed by the line segments are equal.
  • the holes 1c have the same diameter (hereinafter referred to as the hole diameter).
  • the hole diameter of the hole 1c is d1.
  • the outer diameter of the optical fiber 1 is D1.
  • X1 d1 / D1.
  • FIG. 2 is a schematic perspective view of a glass base material for manufacturing the optical fiber 1.
  • the glass base material 2 is a columnar shape made of quartz glass, and a core portion 2a for forming each of the core portion 1a, the cladding portion 1b, and the hole 1c of the optical fiber 1, It has a clad portion 2b and a hole 2c.
  • the air holes 2 c extend along the longitudinal axis of the glass base material 2.
  • the holes 2c have the same hole diameter.
  • the hole diameter of the hole 2c is d2.
  • the outer diameter of the glass base material 2 is D2.
  • Y1 d2 / D2.
  • the length of the glass base material 2 is L1.
  • the glass base material 2 can be prepared as follows, for example. First, using a known method such as a VAD (Vapor phase Axial Deposition) method, an OVD (Outside Vapor Deposition) method, or an MCVD (Modified Chemical Vapor Deposition) method, a glass base material having a core portion 2a and a cladding portion 2b is formed. Form. Thereafter, holes 2c are formed along the longitudinal axis of the glass base material using a drill. Thereby, the glass base material 2 shown in FIG. 2 can be prepared.
  • VAD Very phase Axial Deposition
  • OVD Outside Vapor Deposition
  • MCVD Modified Chemical Vapor Deposition
  • FIG. 3 is a diagram for explaining a drawing process.
  • a drawing apparatus 100 shown in FIG. 3 includes a drawing heating furnace 101 having a heater 101a, a pressurizing mechanism 102, an outer diameter measuring device 103, a coating resin coating apparatus 104, a resin curing apparatus 105, and a capstan roller. 106, a guide roll 107, and a controller C.
  • the pressurizing mechanism 102 includes a pressurizing connector 102a, a gas supply path 102b connected to the pressurizing connector 102a, and a pressure adjusting unit 102c connected to the gas supply path 102b.
  • the pressure adjusting unit 102c is configured by, for example, a mass flow controller (MFC).
  • MFC mass flow controller
  • the drawing process of the optical fiber 1 will be described together with the operation of each component.
  • the glass base material 2 shown in FIG. 2 is set in the drawing heating furnace 101, and the pressure connector 102 a is connected to the upper end of the glass base material 2.
  • the lower end of the glass base material 2 is heated and melted by the heater 101a, and the lower end is drawn.
  • the optical fiber 1 shown in FIG. 1 is drawn from the glass preform 2.
  • gas G is supplied into the air holes 2c of the glass base material 2 and pressurized.
  • the gas G is supplied from the pressurizing connector 102a into the hole 2c through the gas supply path 102b.
  • the pressure of the gas G in the hole 2c is controlled by the pressure adjusting unit 102c controlled by the controller C so that the hole diameter of the hole 1c of the optical fiber 1 becomes d1.
  • the gas G is, for example, argon gas, but may be other inert gas such as helium gas or nitrogen gas.
  • the drawn optical fiber 1 is coated with a known coating resin coating device 104 and resin curing device 105, sent by a capstan roller 106 and a guide roll 107, and wound on a winder (not shown). .
  • the controller C controls the rotational speed of the capstan roller 106 (that is, the drawing speed of the optical fiber 1) so that the outer diameter of the optical fiber 1 measured by the outer diameter measuring device 103 becomes D1.
  • (X1 / Y1) (d1 / D1) / (d2 / D2) ⁇ 1.0.
  • the ratio X1 is 0.028.
  • the hole diameter d2 of the glass base material 2 is 3 mm and the outer diameter D2 is 70 mm
  • the ratio Y1 is 0.043, so X1 / Y1 is 0.65, and (X1 / Y1) ⁇ 1.0 holds.
  • the hole diameter of the holes formed in the glass base material must be reduced to about 2 mm. I must.
  • (X1 / Y1) ⁇ 1.0 is established.
  • the hole diameter d2 of the glass base material 2 is, for example, 3 mm, which is larger than 2 mm, and the hole diameter d2 can be made relatively large.
  • the length can be increased. Therefore, the length L1 of the glass base material 2 can be increased.
  • a hole 2c having a large hole diameter d2 is previously formed in the glass preform 2 with respect to the ratio X1 between the hole diameter d1 and the outer diameter D1 of the optical fiber 1 to be manufactured. I have to. Then, by adjusting the pressure of the gas G in the hole 2c during the subsequent drawing, the ratio of the hole diameter d1 and the outer diameter D1 is adjusted to a desired ratio X1. As a result, since the length of the drill that can be used for forming the hole 2c can be increased while maintaining the mechanical strength, the length of the glass base material 2 can also be increased. Accordingly, the length of the optical fiber 1 that can be manufactured from one glass base material 2 is increased, and thus the manufacturing cost is reduced.
  • the ratio ⁇ (optical fiber hole diameter) / (optical fiber outer diameter) ⁇ between the hole diameter and the outer diameter of the optical fiber is set to X
  • the ratio ⁇ (glass base material) between the hole diameter and the outer diameter of the glass base material is set to X
  • the ratio ⁇ (glass base material) between the hole diameter and the outer diameter of the glass base material is set to X
  • the relationship between the pressure in the pores of the glass base material and the ratio (X / Y) will be described where Y is (hole diameter) / (glass base material outer diameter) ⁇ .
  • a glass base material having an outer diameter of 60 mm having the same structure as the glass base material 2 shown in FIG. 2 and having 10 holes having a hole diameter of 3.5 mm was prepared.
  • an experiment was carried out in which an optical fiber having an outer diameter (cladding diameter) of 125 ⁇ m was drawn from the prepared glass base material with various pressure settings in the glass base material.
  • the pressure in the hole is defined by the dimensionless pressure in the hole.
  • the dimensionless vacancy pressure is the difference between the pressure in the cavities and the atmospheric pressure (hereinafter, this pressure difference is referred to as the vacancy pressure) and the ratio (X / Y) is 1. It is defined as the value divided by the amount of pressurization in the hole.
  • FIG. 4 is a diagram showing the relationship between the dimensionless in-hole pressurization amount and the ratio (X / Y). As shown in FIG. 4, when the amount of pressurization in dimensionless holes is increased, the ratio (X / Y) is increased accordingly. Therefore, a desired ratio (X / Y) can be realized by controlling the pressure in the holes in accordance with the relationship between the dimensionless pressure in the holes and the ratio (X / Y) as shown in FIG. it can.
  • the fluctuation of the hole diameter is defined by the dimensionless hole diameter fluctuation.
  • the dimensionless hole diameter variation is the fluctuation amount per 1 km of optical fiber (maximum value and minimum value) of the average hole diameter (unit: ⁇ m) of 10 holes when the ratio (X / Y) is a certain value. (Hereinafter referred to as pore diameter fluctuation) is divided by the hole diameter fluctuation where the ratio (X / Y) is 1.
  • FIG. 5 is a diagram showing the relationship between the ratio (X / Y) and the dimensionless pore diameter variation. As shown in FIG. 5, it is preferable that X / Y is 0.5 or more because the dimensionless pore diameter variation is smaller than 1.5, and the variation in the longitudinal direction of the pore diameter is reduced.
  • the ratio (X / Y) is smaller than 1.0, the length of the glass base material can be increased. However, if the ratio (X / Y) is 0.7 or less, the effect is remarkable. This is more preferable.
  • Example 1 Comparative Example 1
  • a glass base material having a core portion containing Ge in the center portion and a cladding portion around the core portion was obtained. Furthermore, this glass base material was extended
  • stretched with the oxyhydrogen flame burner the method by the heating with an electric furnace may be used.
  • the cross-sectional refractive index distribution shape of this glass base material was a substantially rectangular shape (step index) with a relative refractive index difference of 0.35%.
  • a drilling process was performed on one of the prepared glass base materials to form ten holes having a diameter of 1.9 mm along the longitudinal axis.
  • the length of the glass base material was set to 350 mm because of the mechanical strength of the drill used at this time.
  • the glass base material of the comparative example 1 was prepared.
  • the glass base material of Example 1 was prepared. The distance between the center of the core portion and the center of the hole in the glass base material of Example 1 and the distance in the glass base material of Comparative Example 1 were the same.
  • the optical fiber is drawn while pressurizing the pores of the glass base material of Example 1 and Comparative Example 1, and Examples 1 and 1 of Comparative Example 1 are drawn.
  • An optical fiber was manufactured.
  • Argon gas was used as the pressurized gas.
  • the amount of pressurization in the holes was adjusted so that the average hole diameter of the ten holes was 3.5 ⁇ m.
  • the average hole diameter of the manufactured optical fiber was 3.55 ⁇ m in Example 1, and 3.51 ⁇ m in Comparative Example 1.
  • the outer diameter of each of the optical fibers of Example 1 and Comparative Example 1 was set to 125 ⁇ m. Therefore, in the case of Example 1, the ratio (X / Y) was 0.57, and in the case of Comparative Example 1, the ratio (X / Y) was 1.
  • the transmission loss of the optical fiber of Example 1 was 0.197 dB / km
  • the transmission loss of the optical fiber of Comparative Example 1 was 0.198 dB / km, which was substantially the same.
  • the difference in the values of the optical fibers of Example 1 and Comparative Example 1 was within 10%. Therefore, the optical fibers of Example 1 and Comparative Example 1 had substantially the same characteristics.
  • the glass base material of Example 1 is twice or more longer than the glass base material of Comparative Example 1, the optical fiber of Example 1 is longer than the optical fiber of Comparative Example 1 from each glass base material. Even a long optical fiber was obtained. Therefore, the manufacturing cost of the optical fiber of Example 1 was lower.
  • Example 2 A glass base material having an outer diameter of 70 mm having the same structure as in Example 1 and Comparative Example 1 is prepared, and drilling is performed using a drill to form a hole having a diameter of 3.0 mm along the longitudinal axis. Ten were formed. The drill used at this time had a diameter larger than that of Comparative Example 1 and the drill had higher rigidity, so that the length of the glass base material could be 850 mm. Thereby, the glass base material of Example 2 was prepared.
  • Example 2 the optical fiber was drawn while pressurizing the inside of the glass base material of Example 2 to produce the optical fiber of Example 2.
  • the pressurization amount in the holes was adjusted so that the average hole diameter of the ten holes of the optical fiber was 3.5 ⁇ m.
  • the average hole diameter of the manufactured optical fiber was 3.53 ⁇ m.
  • the outer diameter of the optical fiber was set to 125 ⁇ m. Therefore, in the case of Example 2, the ratio (X / Y) was 0.65.
  • the transmission loss of the optical fiber of Example 2 was 0.196 dB / km, which was substantially the same as Example 1 and Comparative Example 1.
  • the difference in values between the optical fiber of Example 2 and the optical fibers of Example 1 and Comparative Example 1 was within 10%. Therefore, the optical fiber of Example 2 had substantially the same characteristics as those of Example 1 and Comparative Example 1.
  • the glass base material of Example 2 is also twice or more longer than the glass base material of Comparative Example 1, a longer optical fiber was obtained from one glass base material. Therefore, the manufacturing cost of the optical fiber of Example 2 was lower. Further, in the case of the optical fiber of Example 2, the ratio (X / Y) is made larger than that of the optical fiber of Example 1, so that the hole diameter variation in the longitudinal direction of the optical fiber is suppressed to be smaller than that of Example 1. It was done.
  • Example 3 One glass base material having an outer diameter of 70 mm having the same structure as in Example 1 and Comparative Example 1 is prepared, drilling is performed using a drill, and a hole having a diameter of 5.0 mm is formed along the longitudinal axis. Ten were formed. The drill used at this time had a larger diameter than in the case of Examples 1 and 2, and the rigidity of the drill was further increased, so that the length of the glass base material could be 920 mm. Thereby, the glass base material of Example 3 was prepared.
  • Example 3 the optical fiber was drawn while pressurizing the pores of the glass base material of Example 3 to produce the optical fiber of Example 3.
  • the pressurization amount in the holes was adjusted so that the average hole diameter of the ten holes of the optical fiber was 3.5 ⁇ m.
  • the average hole diameter of the manufactured optical fiber was 3.54 ⁇ m.
  • the outer diameter of the optical fiber was set to 125 ⁇ m. Therefore, in the case of Example 3, the ratio (X / Y) was 0.39.
  • the optical fiber of Example 3 had substantially the same characteristics as the optical fibers of Examples 1 and 2 and Comparative Example 1.
  • Example 3 Since the glass base material of Example 3 is longer than the glass base materials of Examples 1 and 2, an optical fiber longer than that of Examples 1 and 2 was obtained from one glass base material. Therefore, the manufacturing cost of the optical fiber of Example 3 was further reduced.
  • the ratio (X / Y) is made smaller than those of Examples 1 and 2, and the hole diameter variation in the longitudinal direction of the optical fiber is the same as that of Comparative Example 1. Although it was about twice as much as the case, it was a value with no problem in use.
  • the hole diameter formed in the glass base material is 3 mm or more because the length of the glass base material can be sufficiently increased and the manufacturing cost can be sufficiently reduced.
  • Example 4 A glass base material having an outer diameter of 70 mm having the same structure as that of Example 1 and Comparative Example 1 was produced, and a drilling process was performed using a drill to form a hole having a diameter of 2.5 mm along the longitudinal axis. Ten were formed. Since the diameter of the drill used at this time was larger than that of Comparative Example 1 and the rigidity of the drill was high, the length of the glass base material was made 480 mm. Thereby, the glass base material of Example 4 was prepared.
  • Example 4 the optical fiber was drawn while pressurizing the pores of the glass base material of Example 4 to produce the optical fiber of Example 4.
  • the pressurization amount in the holes was adjusted so that the average hole diameter of the ten holes of the optical fiber was 3.5 ⁇ m.
  • the average hole diameter of the manufactured optical fiber was 3.54 ⁇ m.
  • the outer diameter of the optical fiber was set to 125 ⁇ m. Therefore, in the case of Example 4, the ratio (X / Y) was 0.79.
  • the transmission loss of the optical fiber of Example 4 was 0.195 dB / km, which was substantially the same as Example 1 and Comparative Example 1. Further, regarding other characteristics such as cutoff wavelength and wavelength dispersion, the difference in values between the optical fiber of Example 4 and the optical fibers of Example 1 and Comparative Example 1 was within 10%. Therefore, the optical fiber of Example 4 had substantially the same characteristics as those of Example 1 and Comparative Example 1.
  • Example 4 Since the glass base material of Example 4 is also longer than the glass base material of Comparative Example 1, a longer optical fiber was obtained from one glass base material. Therefore, the manufacturing cost of the optical fiber of Example 4 was lower. Further, in the case of the optical fiber of Example 4, the ratio (X / Y) was made larger than that of the optical fiber of Example 2, so that the hole diameter variation in the longitudinal direction of the optical fiber was even smaller than that of Example 2. It was suppressed.
  • FIG. 6 is a schematic cross-sectional view of an optical fiber manufactured by the manufacturing method according to the second embodiment. As shown in FIG. 6, the optical fiber 3 has holes 3a and 3b extending along the longitudinal axis.
  • the optical fiber 3 is made of a material such as pure quartz glass.
  • the holes 3 a and 3 b are regularly arranged in a triangular lattice pattern in a cross section perpendicular to the longitudinal axis of the optical fiber 3. However, there is a region where there is no hole in the region where the holes 3a and 3b are arranged.
  • hole functions as the core part 3c, and the circumference
  • the two holes 3b are located on both sides of the core portion 3c.
  • the 16 holes 3a have the same hole diameter.
  • the hole diameter of the hole 3a is d31.
  • the two holes 3b have the same hole diameter.
  • the hole diameter of the hole 3b is d32.
  • the hole diameter d32 is set larger than the hole diameter d31.
  • the outer diameter of the optical fiber 3 is D3.
  • the optical fiber 3 can be used as a polarization-maintaining optical fiber because anisotropy occurs in the refractive index distribution of the core 3c due to the holes 3b.
  • FIG. 7 is a schematic perspective view of a glass base material for manufacturing the optical fiber 3.
  • the glass base material 4 has a cylindrical shape made of quartz glass and has holes 4 a for forming the holes 3 a and 3 b of the optical fiber 3.
  • the air holes 4 a extend along the longitudinal axis of the glass base material 4.
  • the hole diameter of the hole 4a is d4.
  • the outer diameter of the glass base material 4 is D4.
  • the length of the glass base material 4 is L2.
  • the holes 4a having the same hole diameter are formed. is doing. As a result, only one type of drill is required for forming the holes 4a in the drilling process, and the work of replacing the drills with different thicknesses is not necessary. Therefore, since the drilling process is simplified, the manufacturing cost can be reduced.
  • the length of the drill for forming the hole having the smallest hole diameter is the shortest.
  • the length of the glass base material is also limited by the length of the shortest drill.
  • the length L2 of the glass base material 4 can be increased without being restricted as described above.
  • a glass base material is formed using a known method such as the VAD method, and then a glass base material is used using a drill. Holes 4a are formed along the longitudinal axis. Thereby, the glass base material 4 shown in FIG. 7 can be prepared.
  • the optical fiber 3 is drawn from the glass base material 4 using a drawing apparatus 100 as shown in FIG.
  • a drawing apparatus 100 it is necessary to form holes 3 a and 3 b having different hole diameters of the optical fiber 3 from the holes 4 a having the same hole diameter of the glass base material 4. Therefore, it is preferable to control the internal pressure separately for the hole 4a for forming the hole 3a and the hole 4a for forming the hole 3b.
  • FIG. 8 is a schematic diagram of a pressurizing mechanism used in the manufacturing method according to the second embodiment.
  • a pressurizing mechanism 110 shown in FIG. 8 is used instead of the pressurizing mechanism 102 shown in FIG.
  • the pressurization mechanism 110 includes a pressurization connector 111, gas supply paths 112 and 113 connected to the pressurization connector 111, and pressure adjustment units 114 connected to the gas supply paths 112 and 113, respectively. 115.
  • the pressure adjusting units 114 and 115 are connected to the controller C.
  • a gas G is supplied to the pressure adjusting units 114 and 115.
  • the pressure connector 111 includes a first pressure part 111a and a second pressure part 111b.
  • the first pressurizing unit 111 a is configured to supply the gas G only to the hole 4 a for forming the hole 3 a of the optical fiber 3 among the holes 4 a of the glass base material 4.
  • the second pressurizing part 111b is configured to supply the gas G only to the hole 4a for forming the hole 3b.
  • the gas G supplied to the hole 4a for forming the hole 3a is supplied to the first pressurizing unit 111a through the gas supply path 112 and is pressured by the pressure adjusting unit 114 controlled by the controller C. Is adjusted.
  • the gas G supplied to the hole 4a for forming the hole 3b is supplied to the second pressurizing unit 111b through the gas supply path 113 and is pressured by the pressure adjusting unit 115 controlled by the controller C. Is adjusted. Therefore, by using the pressurizing mechanism 110, the pressure in each hole 4a can be controlled separately. Specifically, the pressure in each hole 4a is set so that the pressure in the hole 4a for forming the hole 3b is higher than the pressure in the hole 4a for forming the hole 3a. Be controlled.
  • the ratio (X2 / Y2) is set to be smaller than 1.0, and the ratio (X3 / Y2) is set to 1.0.
  • both the ratio (X2 / Y2) and the ratio (X3 / Y2) may be made smaller than 1.0. By making both smaller than 1.0, the glass base material can be made longer.
  • FIG. 9 is a schematic cross-sectional view of another optical fiber that can be manufactured by the manufacturing method according to the second embodiment. As shown in FIG. 9, the optical fiber 5 has holes 5a and 5b extending along the longitudinal axis.
  • the optical fiber 5 is made of a material such as pure quartz glass.
  • the holes 5a and 5b are regularly arranged in a triangular lattice pattern in a cross section perpendicular to the longitudinal axis of the optical fiber 5.
  • region where the hole 5a, 5b is arranged functions as the core part 5c, and the circumference
  • the six holes 5b are positioned so as to surround the core portion 5c.
  • the 12 holes 5a have the same hole diameter.
  • the hole diameter of the hole 5a is d51.
  • the six holes 5b have the same hole diameter.
  • the hole diameter of the hole 5b is d52.
  • the hole diameter d52 is set larger than the hole diameter d51.
  • this optical fiber 5 a region having a low refractive index is formed around the core portion 5c by the hole 5b having a large hole diameter, and a so-called W-shaped cross-sectional refractive index profile is formed.
  • the optical fiber 5 is also controlled to have a different internal pressure depending on each hole 4a from the glass base material 4 having the holes 4a having the same hole diameter shown in FIG. 7 using the manufacturing method according to the second embodiment. However, it can be manufactured by drawing while drawing. Specifically, the pressure in the hole 4a of the glass base material 4 for forming the hole 5b of the optical fiber 5 is higher than the pressure in the hole 4a for forming the hole 5a. The pressure in each hole 4a may be controlled.
  • the glass base material has holes formed by a drill.
  • the present invention can also be applied to a case where a base material is prepared using a glass tube that becomes a hole.
  • the glass tube can be lengthened. Therefore, a longer and larger glass base material can be prepared using a longer glass tube.
  • pressure control is performed so that the ratio (X / Y) ⁇ 1.0 is satisfied for some or all of the plurality of holes in the glass base material.
  • pressure control may be performed so that the ratio (X / Y) ⁇ 1.0 is satisfied with respect to at least one hole.
  • the outer diameter of the glass base material may be adjusted by applying a known jacket method to the glass base material of the above embodiment.
  • the jacket method is a method of forming a glass base material having a larger outer diameter by inserting the glass base material into a quartz glass tube having an inner diameter that is substantially the same as the outer diameter of the glass base material.
  • the present invention can be applied to the manufacture of various optical fibers having a plurality of holes extending along the longitudinal axis such as PBGF.
  • the optical fiber manufacturing method according to the present invention is suitable for use in manufacturing an optical fiber having a plurality of holes.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

La présente invention concerne un procédé de fabrication de fibres optiques comprenant les étapes suivantes : une étape de préparation pour la préparation d'une préforme comportant de multiples trous se prolongeant le long de son axe longitudinal, le rapport entre le diamètre des trous et le diamètre extérieur de la préforme étant défini comme correspondant à un premier rapport ; et une étape d'étirage consistant à chauffer et à faire fondre une extrémité de la préforme tout en appliquant une pression à l'intérieur des multiples trous de la préforme, puis à étirer une fibre optique comportant de multiples trous se prolongeant le long de son axe longitudinal. Si le rapport entre le diamètre d'au moins l'un des trous de la fibre optique et le diamètre extérieur de la fibre optique est défini comme correspondant à un second rapport, la fibre optique est étirée après ajustement de la pression à l'intérieur d'au moins l'un des trous de la préforme de façon telle à ce que le rapport entre le second rapport et le premier rapport diminue jusqu'à atteindre moins de 1,0. Il est ainsi possible de réduire les coûts de fabrication.
PCT/JP2012/052303 2011-02-14 2012-02-01 Procédé de fabrication de fibres optiques WO2012111436A1 (fr)

Applications Claiming Priority (2)

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JP2011-028748 2011-02-14
JP2011028748A JP2012166975A (ja) 2011-02-14 2011-02-14 光ファイバの製造方法

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WO2012111436A1 true WO2012111436A1 (fr) 2012-08-23

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Publication number Priority date Publication date Assignee Title
JP5879842B2 (ja) * 2011-09-12 2016-03-08 住友電気工業株式会社 光ファイバ製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004191947A (ja) * 2002-11-25 2004-07-08 Shin Etsu Chem Co Ltd 空孔ファイバの線引き方法
JP2006083037A (ja) * 2004-09-17 2006-03-30 Fujikura Ltd 光ファイバの製造方法
WO2011052497A1 (fr) * 2009-10-26 2011-05-05 株式会社フジクラ Procédé de soudure, dispositif de soudure et procédé de fabrication de fibre optique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004191947A (ja) * 2002-11-25 2004-07-08 Shin Etsu Chem Co Ltd 空孔ファイバの線引き方法
JP2006083037A (ja) * 2004-09-17 2006-03-30 Fujikura Ltd 光ファイバの製造方法
WO2011052497A1 (fr) * 2009-10-26 2011-05-05 株式会社フジクラ Procédé de soudure, dispositif de soudure et procédé de fabrication de fibre optique

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