WO2002078138A1 - Fibre a double gainage et procede de production d'une fibre a double gainage - Google Patents

Fibre a double gainage et procede de production d'une fibre a double gainage Download PDF

Info

Publication number
WO2002078138A1
WO2002078138A1 PCT/JP2002/002733 JP0202733W WO02078138A1 WO 2002078138 A1 WO2002078138 A1 WO 2002078138A1 JP 0202733 W JP0202733 W JP 0202733W WO 02078138 A1 WO02078138 A1 WO 02078138A1
Authority
WO
WIPO (PCT)
Prior art keywords
clad
fiber
cladding
core
double
Prior art date
Application number
PCT/JP2002/002733
Other languages
English (en)
Japanese (ja)
Inventor
Tetsuya Yamamoto
Norio Naka
Minoru Yoshida
Moriyuki Fujita
Masataka Nakazawa
Hirokazu Kubota
Satoki Kawanishi
Original Assignee
Mitsubishi Cable Industries, Ltd.
Nippon Telegraph And Telephone Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Cable Industries, Ltd., Nippon Telegraph And Telephone Corporation filed Critical Mitsubishi Cable Industries, Ltd.
Publication of WO2002078138A1 publication Critical patent/WO2002078138A1/fr

Links

Classifications

    • 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
    • G02B6/02319—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes characterised by core or core-cladding interface features
    • G02B6/02338—Structured core, e.g. core contains more than one material, non-constant refractive index distribution in core, asymmetric or non-circular elements in core unit, multiple cores, insertions between core and clad
    • 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
    • C03B37/0122—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 for making preforms of photonic crystal, 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
    • 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
    • G02B6/02361—Longitudinal structures forming multiple layers around the core, e.g. arranged in multiple rings with each ring having longitudinal elements at substantially the same radial distance from the core, having rotational symmetry about the fibre axis
    • 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
    • C03B2203/12—Non-circular or non-elliptical cross-section, e.g. planar core
    • 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
    • C03B2203/10—Internal structure or shape details
    • C03B2203/22—Radial profile of refractive index, composition or softening point
    • C03B2203/23—Double or multiple optical cladding profiles
    • 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

Definitions

  • the present invention relates to a double clad fiber used in a fiber-to-the-fiber fiber amplifier and a method for manufacturing the same.
  • a core single mode core doped with an excitation light active material, a first cladding covering the periphery of the core, and a second cladding covering the periphery of the first cladding are provided.
  • Double-cladded fiber is known.
  • the double clad fin is used for a fiber laser or a fiber amplifier.
  • a signal light is propagated in the core of the double clad, while an excitation light for exciting the signal light is used. Is propagated in the first class.
  • the excitation light active substance is activated, and as a result, the signal light is amplified.
  • the refractive index of the second cladding needs to be lower than that of the first cladding in order to improve the numerical aperture of the pumping light. Therefore, in the conventional double cladding mode fiber, while the upper SL core and first Kuradzu de formed by quartz (S i 0 2), and the second clad so as to form, for example, by a UV-curable resin I have.
  • the numerical aperture for excitation light is only about 0.5, and further improvement of the numerical aperture cannot be expected.
  • forming the second cladding with a resin also causes a problem of thermal stability in the double cladding fiber.
  • the present invention has been made in view of such circumstances, and an object of the present invention is to provide a double clad fiber having an improved numerical aperture for excitation light and a method for manufacturing the same. Disclosure of the invention
  • a core which extends in a central axis direction of a fiber and through which signal light propagates, a first cladding covering the periphery of the core and through which pumping light for pumping the signal light propagates, and the first cladding. And a second cladding fiber covering the periphery of the cladding.
  • the second cladding has a porous structure having a large number of fine pores extending in the fiber central axis direction.
  • the core is preferably doped with an excitation light active substance.
  • the excitation light active substance may be, for example, a rare earth element.
  • the rare earth element may be at least one of erbium (Er), neodymium (Nd), and ytterbium (Yb).
  • the core is doped with a material for increasing the refractive index, for example, germanium (Ge) in order to increase the refractive index more than the first clad.
  • the second cladding has a porous structure having a large number of pores extending in the direction of the central axis of the fiber. For this reason, the refractive index of the second class (impeached refractive index) is determined by the refractive index of the air in each hole and the refractive index of the portion other than this hole.
  • the effective refractive index of the second cladding changes according to the porosity of the second cladding (the ratio of the total volume (or cross-sectional area) of the holes to the total volume (or cross-sectional area) of the second cladding).
  • the porosity of the second cladding the ratio of the total volume (or cross-sectional area) of the holes to the total volume (or cross-sectional area) of the second cladding.
  • the higher the porosity the lower the effective refractive index of the second clad. Therefore, by lowering the effective refractive index of the second cladding, the relative refractive index difference between the second cladding and the first cladding can be made relatively large. As a result, the numerical aperture of the double-cladding fiber for pump light is greatly increased. It is possible to increase.
  • the second clad is also made of S i 0 2, only Rukoto changing the porosity of the second clad, and a large child relative refractive index difference between the second clad and the first clad it can. Therefore, it is not necessary to form the second clad with resin. That is, the second Kuradzu de by a S i 0 2 made, thermal stability problems of da Purukura' Dofuaiba is eliminated.
  • the first and second cladding fibers have a porous structure having a large number of pores extending in the central axis direction of the fiber.
  • the second invention unlike the first invention, not only the second cladding but also the first cladding has a porous structure.
  • the refractive index (effective refractive index) of the first cladding changes.
  • the core diameter of the double clad fiber can be increased.
  • the excitation light active substance is doped in the core and Ge is doped, for example.
  • the excitation light active substance may be a rare earth element such as Er, Nd, or Yb.
  • the porosity of the first clad is set lower than the porosity of the second clad.
  • the effective refractive index of the second cladding becomes smaller than the effective refractive index of the first cladding. This makes it possible to propagate the excitation light in the first cladding.
  • the porosity of the first clad be set to 2.5% or less. By doing so, the relative refractive index difference between the core and the first clad becomes relatively small. Therefore, as described above, even if the core diameter is increased, the core becomes a single mode core.
  • the pores of the first clad may be periodically arranged in the cross section of the fiber.
  • the effective refractive index of the first clad has wavelength dependence. For this reason, the condition for the core to be in a single mode exists for all the wavelengths of the signal light.
  • the cross-sectional shape of the first clad may be, for example, a polygonal shape such as a triangle, a quadrangle and a hexagon, a circular shape or an elliptical shape. .
  • the first and second inventions relate to the double clad fiber, but the third to fifth inventions relate to a method for manufacturing a double clad fiber.
  • a core extending in a central axis direction of a fiber, through which a signal light propagates, a first cladding that covers the periphery of the core, and through which a pump light for exciting the signal light propagates, and a first clad.
  • the present invention relates to a method for producing a double clad fiber including a second cladding covering the periphery of the cladding.
  • the third invention provides a first preform having a core portion serving as a core of the double clad fiber, and a first cladding portion covering a periphery of the core portion and serving as a first clad of the double clad fiber.
  • a first preform manufacturing step to be manufactured; and disposing the first preform in a cylindrical support tube such that the core portion is located substantially at the center of the support tube.
  • a second clad portion serving as a second clad of the double clad fiber is formed to form a second preform.
  • a first preform having a core portion and a first clad portion surrounding the core portion is produced.
  • the procedure for producing the first preform is as follows: (1) A preform having a core portion and a cladding portion (first cladding portion) is formed by a known production method such as a VAD method, an OVD method, or a rod-in-tube method.
  • the preform may be manufactured, and (2) the preform may be subjected to grinding so that the preform has a desired cross-sectional shape.
  • a second preform is produced. That is, the first preform is disposed in the cylindrical support tube such that the core portion of the first preform is located substantially at the center of the support tube. At the same time, a plurality of tubular cavities are arranged between the first preform and the support tube to form a second cladding portion.
  • the second preform thus manufactured is heated and drawn in a drawing step to draw a fiber.
  • the first preform becomes a double clad fiber core and a first clad.
  • the holes of each capillary in the second cladding section form pores extending in the central axis direction of the fiber in the second cladding of the double clad fiber.
  • the second cladding of the double cladding fiber has a porous structure.
  • the second clad having a porous structure can be manufactured only by disposing a plurality of cavities in the support tube.
  • the manufacturing process of the first preform is a process that has been conventionally performed when manufacturing a double clad fiber.
  • the preform is subjected to grinding, it is extremely complicated and has a disadvantage that it is difficult to form a complicated cross-sectional shape.
  • the fourth invention solves this inconvenience, and the double This is a method that makes it easier to manufacture a bus.
  • the method for manufacturing a double clad fiber according to the fourth invention includes a preform manufacturing step of manufacturing a preform, and a drawing step of heating and stretching the preform to draw a fiber.
  • the preform manufacturing step includes arranging at least one rod-shaped core port substantially at the center of the cylindrical support pipe, thereby forming the double-clad fiber.
  • the core forming step in the preform manufacturing step at least one rod for a rod-shaped core is disposed substantially at the center of the cylindrical support pipe.
  • a core portion serving as a core of the fiber is formed.
  • the number of core ports arranged in the sabot pipe is appropriately determined according to the diameter of this port and the core diameter of the double clad fiber after the preform is bowed.
  • the core rod may be, for example, one doped with an excitation light active substance or Ge.
  • a first clad part forming step a plurality of rod-shaped first clad rods are arranged around the core part in the support pipe. As a result, a first clad portion serving as a first clad of the fiber is formed.
  • a plurality of tubular second clad cavities are arranged between the first cladding portion and the support pipe.
  • a second cladding portion that becomes the second cladding of the fiber is formed.
  • the first clad portion of the preform includes a plurality of first clad portions. It is formed by a doodling rod. Therefore, by simply adjusting the arrangement of the rod, the first cladding portion (the first cladding of the double clad fiber) can be formed into a desired cross-sectional shape, for example, a polygonal shape, a circular shape, or an elliptical shape. Can be formed. Therefore, there is no need to perform a grinding process in the production of a double clad fiber, and the production cost is greatly reduced.
  • a first clad rod is provided at a boundary between the first clad part and the second clad part in the cross section of the preform.
  • a mixed layer in which the second cladding cavities and the second cladding cavities are alternately arranged along the boundary may be provided.
  • the first clad and the second clad are drawn in the cross section of the double clad fiber obtained by drawing the preform.
  • the shape of the interface with the 2nd grade becomes a waveform.
  • the excitation light propagating in the first clad is randomly reflected at this interface. For this reason, the probability that the above-mentioned pumping light crosses the core is increased, and the pumping efficiency of the double clad fiber is improved.
  • the method for producing a double clad fiber according to the fifth invention is suitable for producing the double clad fiber according to the second invention.
  • the method for producing a double clad fiber according to the fifth invention includes a preform producing step of producing a preform, and a drawing step of heating and stretching the preform to draw a fiber.
  • the preform manufacturing step includes disposing at least one rod-shaped core rod substantially at the center of the cylindrical support tube, so that the core as the core of the double clad fiber is formed. Forming a cylindrical portion around the core portion in the support pipe and forming a plurality of cylindrical first clad capillaries to form the first clad of the double clad fiber.
  • the first cladding part forming step of forming the first cladding part, and a plurality of cylindrical second clad cavities are disposed between the first cladding part and the support pipe, thereby achieving the above-mentioned. Forming a second clad portion forming a second clad portion of the double clad fiber.
  • the first clad portion of the preform is formed by the plurality of first clad cavities, as described above, only the arrangement of the first clad cavities is adjusted.
  • the first cladding portion (the first cladding of the double clad fiber) having a desired cross-sectional shape can be formed. Therefore, the production cost of double clad fiber is greatly reduced.
  • FIG. 1 is a sectional view showing a double clad fiber according to the first embodiment.
  • FIG. 2 is a cross-sectional view showing a preform of the double clad fiber according to the first embodiment.
  • FIG. 3 is an enlarged cross-sectional view showing an interface between the first and second claddings.
  • FIG. 4 is an enlarged cross-sectional view showing an example in which a mixed layer is provided at the interface between the first and second cladding portions.
  • FIG. 5 is an enlarged cross-sectional view showing an interface portion between the first and second cladding portions when a cabillary and a rod having a regular hexagonal cross section are used.
  • FIG. 6 is an enlarged cross-sectional view showing an example in which a mixed layer is provided at the interface between the first and second cladding portions when a hexagonal cross-sectioned cabillary and a rod are used.
  • FIG. 7 is a cross-sectional view showing a preform of a double clad fiber according to a modification of the first embodiment.
  • FIG. 8 is a cross-sectional view showing a double clad fiber according to the second embodiment.
  • FIG. 9 is a cross-sectional view showing a preform of a double clad fiber according to the second embodiment.
  • FIG. 1 shows a double clad finino 1 according to a first embodiment of the present invention.
  • the double clad fiber includes a core 11 through which the signal light propagates, a first clad 12 covering the core 11 and propagating the pump light for exciting the signal light, and a first clad 12 And a support portion 14 that covers the periphery of the second clad 13.
  • the core 11 is a single mode core made of Si 2 , and is disposed so as to extend in the direction of the center axis of the double clad fin 1 at substantially the center of the double clad fin 1.
  • the core 11 is doped with, for example, Ge so as to have a higher refractive index than the first clad 12.
  • a rare earth element specifically, Er, Nd, Yb
  • Etc. is so amplified that the signal light propagating in the core 11 is amplified by the pumping light propagating in the first clad 12.
  • the first clad 12 is made of Si 2 , and extends in the central axis direction of the double clad fiber 1 while covering the periphery of the core 11.
  • the cross-sectional shape of the first clad 12 is formed in a substantially regular hexagonal shape in the illustrated example, the cross-sectional shape of the first clad 12 is not limited to a regular hexagonal shape, but may be a triangular shape, a rectangular shape, or the like. Polygonal shape, circular shape, elliptical shape, or the like.
  • the second clad 1 3 is a S i 0, Ltd. 2, while covering the periphery of the first Kuradzu de 1 2 are arranged to extend in the direction of the central axis of the double clutch mode fiber 1.
  • the second clad 13 is a double clad fiber 1 It has a number of holes 13a, 13a, ... extending in the direction of the central axis, and has a porous structure.
  • the plurality of holes 13a, 13a,... Are arranged so as to be almost closest to each other in the cross section of the double clad fino 1.
  • the holes 13 a, 13 a,... May be arranged so as to be substantially uniform in the circumferential direction in the fiber cross section without being arranged so as to be almost the closest.
  • the support part 14 is provided so as to cover the second clad 13.
  • the support part 14 plays a role of protecting the second clad 13 having a porous structure and improving the mechanical strength of the double clad fiber 1.
  • a coating material for example, a coating material made of an ultraviolet-curable resin
  • a communication optical fiber or the like for normal communication is provided around the support portion 14. Is good.
  • the double clad fiber 1 has a second clad 13 having a porous structure having a large number of pores extending in the central axis direction of the fiber. Therefore, the refractive index of the second Kuradzu de 1 3 (the effective refractive index), each hole 1 3 a, 1 3 a, the refractive index of air in ..., S i 0 2 part (hole other than the hole Between the hole and the hole). That is, the effective refractive index of the second clad 13 changes according to the porosity of the second clad 13. Specifically, the smaller the porosity is, the larger the effective refractive index of the second clad 13 is, and the larger the porosity is, the smaller the effective refractive index of the second clad 13 is.
  • the holes 13a, 13a, ... are typically arranged closest to each other, but in the second clad 13, a pair of adjacent holes 13a, 13a are formed.
  • the porosity of the second cladding 13 is calculated by the ratio of the pitch ⁇ ⁇ to the diameter d of each hole 13 a. (D / ⁇ ). That is, as d / ⁇ is smaller, the porosity is smaller and the effective refractive index of the second clad 13 is larger. As d / ⁇ is larger, the porosity is larger and the second clad 13 is larger. Has a small effective refractive index.
  • the effective refractive index of the second clad 13 can be changed to about 1-1.46.
  • the numerical aperture for the excitation light of the double-clad Fino'1 can be changed to about 0.01 to 0.99.
  • a conventional double-clad fiber in which the second clad is formed of an ultraviolet curable resin has a numerical aperture of about 0.5. Therefore, by making the second clad 13 have a porous structure, it is possible to greatly increase the numerical aperture for pumping light as compared with a conventional double clad fiber.
  • the second clad 1 3 is made of S i 0 2, it is possible to improve the thermal stability of the Daburukuradzu Dofuaino '1.
  • FIG. 2 shows preform 2 of double clad fino 1. Since the preform 2 is symmetrical, the right half of the preform 2 is not shown in FIG.
  • the method for manufacturing the double clad fiber 1 according to the first embodiment includes a preform manufacturing step of manufacturing the preform 2 and a drawing step of heating and stretching the preform 2 to draw a fiber. Become.
  • a preform manufacturing process will be described.
  • a cylindrical support tube 24 having a substantially circular cross section was prepared, and a rod 2 for a core having a circular cross section and a rod shape made of Si02 was placed substantially in the center of the support tube 24. 7 las will be provided.
  • the core 21 serving as the core 11 of the double clad fiber 1 is formed (core part forming step).
  • the core part 21 is provided with six core rods 21a around one core port 21a arranged substantially at the center of the support pipe 24 so as to be in contact with each other. By doing so, it suffices if the whole is formed so as to have a substantially circular cross section.
  • the core port 21a be doped in advance with Ge for increasing the refractive index and an excitation light active substance.
  • the number of core rods 21 a forming the core portion 21 may be appropriately adjusted according to the diameter of the core rod 21 a and the diameter of the core 11 in the double-cladding fiber 1.
  • first clad portion 22 that becomes the first clad 12 of the double clad fiber 1 is formed (first clad portion forming step).
  • first clad rods 22 a are arranged in the closest density so that the first clad portion 22 has a substantially regular hexagonal cross section. If the first clad 12 in the double clad fiber 1 after the drawing step becomes solid, it is not necessary to arrange the first clad rod 22a in the closest density.
  • the first clad load 22a for example, one obtained by doping Ge or the like may be used.
  • a second clad portion 23 that becomes the second clad 13 of the double clad fiber 1 is formed (a second clad portion forming step). It is also preferable to arrange the second cloud cable 23a in the closest density.
  • the holes 13 a, 13 a,... In the second clad 13 of the double clad fiber 1 are arranged in the circumferential direction of the double clad fiber 1 even if the second clad cavities 23 a are not dense. They may be arranged so as to be distributed almost uniformly. However, it is preferable that the above-mentioned second clad cavities 23a are arranged such that the pitch ⁇ is 5 m or less in the second clad 13 of the double clad huino '1.
  • the preform in which the core port 21a, the first clad rod 22a, and the second clad cab 23a are disposed in the support pipe 24 is provided.
  • 2 is prepared (preform preparation step). Note that there is no limitation on the order in which the core part forming step, the first cladding part forming step, and the second cladding part forming step are performed.
  • the preform 2 is heated and drawn into a fiber in a drawing furnace (not shown) (drawing step). In this drawing step, a coating material may be provided around the fiber 1.
  • the holes of the second clad cavities 23 a form the holes of the second clad 13.
  • the second clad 13 has a porous structure.
  • the first clad rods 22a are fused together to form the first clad 12, and the core claws 21a are fused together to form the core 11a.
  • the double clad fiber 1 as shown in FIG. 1 is manufactured.
  • the support tube 24 forms the support portion 14 of the double clad fiber 1.
  • the second clad of the double-clad fiber 1 is formed. 13 can be configured in a porous structure. Also, when fabricating the preform 2, the inner diameter of the second clad cab 23a and the pitch at which the second clad cab 23a is arranged (a pair of capillaries 23a, 2a). By simply changing the distance between 3a, the diameter d and the radius of the hole 13a of the second clad 13 are changed, and the effective refractive index of the second clad 13 is changed. Can be done.
  • the first clad portion 22 of the preform 2 is also formed by a plurality of first clad rods 22a, the first clad portion 22 (double clad) can be formed without performing a grinding step.
  • the first cladding 12) of the fiber 1 can be formed into a desired cross-sectional shape.
  • the cross-sectional shape of the first clad 12 (first clad part 22) is substantially a regular hexagon, but the arrangement of the first clad rod 22a may be adjusted.
  • the first cladding 12 can be formed in a polygonal shape such as a triangular shape or a rectangular shape, a circular shape, an elliptical shape, or the like.
  • the boundary between the first cladding part 22 and the second cladding part 23 in the preform 2 may be configured, for example, as shown in FIG.
  • the first cladding rod 22a is placed closest to one side of the boundary (boundary interface) S, while the second cladding rod is placed on the other side of the boundary S.
  • Only the cabillary 23a is placed closest.
  • the first cladding rod 22 a and the second cladding cab 23 a may be individually arranged to form the boundary surface S.
  • the boundary between the first cladding section 22 and the second cladding section 23 may be configured as shown in FIG. 4, for example. That is, at this boundary, the first clad load 22 a and the second clad cab 23 a are alternately arranged along the boundary (boundary surface) S. A layer 25 may be provided.
  • the mixed layer 25 is provided in this manner, the interface shape between the first clad 12 and the second clad 13 in the double clad fiber 1 has a waveform c. Therefore, the excitation light is randomly reflected at this interface. I will be. As a result, the probability that the pumping light crosses the core 11 is further increased, and the pumping efficiency of the double-class fiber 1 can be further improved.
  • the first cladding rod 22a is not limited to the one having a circular cross section, and may be, for example, a rod-shaped member 22b having a regular hexagonal cross section as shown in FIG.
  • the second clad cavity 23a may be a cylindrical member 23b having a regular hexagonal cross section.
  • the cross-sectional shape of the hole of the second clad cavity 23b is formed in a circular shape, but the cross-sectional shape of the hole is not limited to a circular shape.
  • the side surfaces of the door 22b or the second clad cab 23b may be arranged side by side so as to be in close contact with each other. By doing so, there is no gap between the adjacent first-class rods 22b or second-layer cabillary 23b, and these first-class rods 22b.
  • the cross-sectional shape of the first clad rod 22 b and the second clad cab 23 is a regular hexagon, as shown in FIG. 6, the first clad portion of the preform 2 At the boundary between the second and second cladding sections 23, the first cladding rods 22b and the second cladding cab 23b are alternately arranged along the boundary surface S.
  • a mixed layer 25 may be provided.
  • FIG. 7 also shows the preform 3 of the double clad fiber 1, but similarly to FIG. 2, illustration of the right half of the preform 3 is omitted.
  • the manufacturing method of the double-clad finos 1 according to this modification includes a first preform manufacturing step, a second preform manufacturing step, and a drawing step of heating and stretching the second preform to draw a fiber shape.
  • a core 31 serving as the core 11 of the double clad fiber 1 and a first clad 12 of the double clad fiber 1 covering the periphery of the core 32 are formed.
  • the first preform 35 has a core portion 31 and a cladding portion (first cladding portion 32) by a known method such as a VAD method, a 0 VD method, or a mouth-drawing method.
  • a preform may be manufactured, and thereafter, may be manufactured by subjecting the preform to grinding so that the preform has a substantially hexagonal cross-sectional shape.
  • a cylindrical support tube 34 is prepared, and the first preform is placed so that the core 31 of the first preform 35 is located substantially at the center of the support tube 34.
  • the system 35 is disposed in the cylindrical support tube 34.
  • the second clad portion 33 is formed.
  • the second clad cavity 33a may be the same as the second clad cavity 23a in the first embodiment. Further, in the example shown in the figure, the above-mentioned second cladding rod 33a is arranged closest, but the second cladding rod 33a does not have to be arranged closest. .
  • each of the first preform 35 and the plurality of second clad cavities 33 a produces the second preform 3 disposed in the support tube 34 (second preform production step).
  • the first preform 35 may be provided after the second clad cavities 33a are provided in the sabot tube 34 first.
  • the drawing process performed on the produced second preform 36 is the same as that described in the first embodiment, and the description thereof is omitted here.
  • FIG. 8 shows a double clad fiber 5 according to a second embodiment of the present invention.
  • the double-clad fire 5 has a porous structure in which both the first and second clads 52, 53 have a large number of holes 52a, 53a extending in the direction of the central axis of the fiber. This point is different from the first embodiment.
  • the first clad 52 is formed in a substantially rectangular cross-section (see the dashed line in the figure), but the first clad 52 is replaced by other polygonal shapes, circular shapes, Alternatively, it may be formed in an elliptical shape as in the first embodiment.
  • first clad 52 having a porous structure
  • the holes 52 a and 53 a of the first and second clads are arranged closest.
  • Each hole 52 a in the first clad 52 When the diameter of each hole 53a in the second clad 53 is d2 and the pitch is ⁇ 2, the first clad 52
  • the porosity of the first clad 52 be lower than the porosity of the second clad 53.
  • the effective refractive index of the second clad 53 becomes smaller than the effective refractive index of the first clad 52, and the pumping light can be propagated in the first clad 52. become.
  • the first cladding 52 is
  • the porosity of the first clad 52 is set to 2.5% or less.
  • the relative refractive index difference between the core 51 and the first clad 52 becomes relatively small, so that even if the diameter of the core 51 of the double clad fiber 5 is increased, the core 51 becomes a single mode. .
  • the holes 52a of the first clad 52 are periodically arranged in the cross section of the fiber.
  • the periodical arrangement of the holes 52a of the first clad 52 includes the arrangement of the holes 52a of the first clad 52 in the closest density.
  • the effective refractive index of the first clad 52 has wavelength dependence. As a result, there is a condition that the core 51 becomes a single mode for all wavelengths of the signal light.
  • the fabrication of the preform 4 according to the second embodiment is different from the fabrication of the preform 2 according to the first embodiment (see FIG. 2) in that the first clad portion 42 is formed into a circular cross-section and a cylinder.
  • the only difference is that the shape is formed by arranging the first-stage cable carrier 42a. Therefore, when producing the preform 4, the core part 41 is formed by disposing the core rod 4 la in the support pipe 44, or the second clad cavities 4 are provided. By disposing 3a, the second clad portion 43 is formed, but this procedure is the same as that for producing the preform 2 according to the first embodiment. Therefore, the description is omitted.
  • the first and second satisfies the above equations (1) and (2).
  • the outer diameter of the first clad cavity 42a is the same as the outer diameter of the second clad cavity 43a, while the inner diameter is the second clad cavity 42a. If a smaller diameter than the inside diameter of the capillary 43a is used, the first class 52 satisfies the above expression (1).
  • the double clad fin 5 according to the second embodiment has a structure in which the core 51 and the first clad 52 are formed because the first clad 52 has a porous structure.
  • the relative refractive index difference can be easily changed. Thereby, it is possible to configure the double clad fiber 5 in which the diameter of the core 51 is enlarged while satisfying the condition of the single mode.
  • the double-clad finos 5 in which the first and second clads 52 and 53 have a porous structure, respectively, are also provided with the first and second clad cavities 42 a and 43 a in the support pipe 44. It can be manufactured simply by disposing. Furthermore, since the first clad 52 is formed by the first clad cavities 42a, the first clad 52 can be easily formed in a sectional shape. Next, an example in which a double clad fiber is manufactured by the manufacturing method according to the present invention will be described.
  • Example 1 is an example in which a double clad fiber was manufactured by the manufacturing method according to the first embodiment.
  • the support pipes and the like used in the first embodiment are as follows.
  • ⁇ relative refractive index difference.
  • Sabot tube 40 mm x 5 t X 300 mm L Core rod ( ⁇ 1.0% (Ge dope), Yb dope (3000 ppm)):
  • Cable for the second clad O.D. 0500 ⁇ m, I.D. 02 O O ⁇ mX 3 O 0 mmL
  • the first clad rod 22a was formed around the core 21 so as to be closest to the hexagonal cross section of the first clad rod 22a, thereby forming the first clad part 22.
  • the second clad cab 23a is arranged between the first clad portion 22 and the support pipe 24 in the closest density to form the second clad portion 23.
  • the above-mentioned second clad cavity 23a is subjected to chlorination and the openings at both ends thereof are closed.
  • the preform 2 thus produced was set on a lathe and subjected to chlorination, and the inside of the support tube 24 was closed after the pressure inside the support tube 24 was reduced.
  • the preform 2 was drawn to produce a double clad fiber with an outer diameter of ⁇ 125 m. At the time of this drawing process, coating was performed to provide a coating material around the fiber.
  • the double clad fiber 1 (see FIG. 1) manufactured in this manner has a core 11 having a diameter of approximately ⁇ 5 mm and a first cladding 12 having a size (diagonal length of a regular hexagonal cross section) of approximately 60 mm.
  • the diameter of the second clad 13 was 94 m. Further, the diameter d of each hole 13a of the second clad 13 was 1. l ⁇ m, and the pitch was 1.6 1.m.
  • the numerical aperture of the double clad fiber 1 for the excitation light was 0.85 to 0.86.
  • the second example is an example in which a double clad fiber is manufactured by the manufacturing method according to the second embodiment.
  • the support pipes and the like used in the second embodiment are as follows.
  • Support tube 04 Ommx 5 t x 3 O O mmL
  • Core rod ( ⁇ 1.0% (Ge dope), Yb dope (300 ppm)): ⁇ 500 ⁇ 300 mmL
  • Cylinder for the first class outer diameter 500 mm, inner diameter 0 1 O O ⁇ mx 3 O 0 mmL
  • 2nd class cable cab outer diameter 500 mm, inner diameter 035 Omx3O0 mmL
  • the core rod 41 a was disposed substantially at the center of the support pipe 44 to form a core portion 41.
  • the first clad cavities 42a were disposed around the core 41 so as to have a substantially rectangular cross section, thereby forming the first clad 42.
  • the second clad gallery 43 a was disposed between the first clad portion 42 and the support pipe 44 to form the second clad portion 43.
  • the cavities 42a and 43a for the first and second clads are chlorinated and the openings at both ends are closed.
  • the preform 4 thus produced was set on a lathe and subjected to chlorination. Further, the inside of the support tube 44 was sealed after the inside of the support tube 44 was depressurized.
  • the preform 4 was drawn to produce a double clad fiber having an outer diameter of ⁇ 125 mm. At the time of this drawing process, coating was performed to provide a coating material around the fiber.
  • the diameter of the core 51 is approximately ⁇ 2.4 jm, and the diameter d 1 of each hole 52 a of the first clad 52 is 0. 9 m, pitch 1 is 1.6 m, each hole of second clad 53 3
  • the diameter d2 was 1.4111, and the pitch ⁇ 2 was 1.6 zm.
  • the numerical aperture of the double-clad fiber 5 for pumping light was 0.85 to 0.86.

Landscapes

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

Abstract

Un procédé de production d'une fibre à double gainage comprend les étapes suivantes: on étire une préforme (2) qui a été produite en disposant des bâtonnets centraux (21a), des bâtonnets (22a) de première gaine et des capillaires (23a) de deuxième gaine dans un tube-support (24) pour assurer la fibérisation, ceci permettant de former une deuxième gaine (13) d'une fibre (1) à double gaine dans une structure poreuse ayant un grand nombre de pores (13a) s'étendant dans le sens de l'axe central de la fibre.
PCT/JP2002/002733 2001-03-22 2002-03-22 Fibre a double gainage et procede de production d'une fibre a double gainage WO2002078138A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001081963A JP4080701B2 (ja) 2001-03-22 2001-03-22 ダブルクラッドファイバ及びその製造方法
JP2001-81963 2001-03-22

Publications (1)

Publication Number Publication Date
WO2002078138A1 true WO2002078138A1 (fr) 2002-10-03

Family

ID=18937969

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2002/002733 WO2002078138A1 (fr) 2001-03-22 2002-03-22 Fibre a double gainage et procede de production d'une fibre a double gainage

Country Status (2)

Country Link
JP (1) JP4080701B2 (fr)
WO (1) WO2002078138A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1571131A2 (fr) * 2004-03-03 2005-09-07 Samsung Electronics Co., Ltd. Procédé de fabrication d'une préfrome pour une fibre optique à trous
CN112408773A (zh) * 2020-10-29 2021-02-26 东北大学 D形光子晶体光纤预制棒及其d形光子晶体光纤拉制方法

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6917741B2 (en) * 2002-11-18 2005-07-12 Corning Incorporated Methods for manufacturing microstructured optical fibers with arbitrary core size
JP4561314B2 (ja) 2004-10-28 2010-10-13 日立電線株式会社 ファイバレーザ用光ファイバ、ファイバレーザ及びレーザ発振方法
JP5102979B2 (ja) * 2006-06-12 2012-12-19 三菱電線工業株式会社 レーザー光の出射方法
JP4490464B2 (ja) * 2007-08-24 2010-06-23 日本電信電話株式会社 光ファイバ及びその製造方法
JP4490465B2 (ja) * 2007-09-11 2010-06-23 日本電信電話株式会社 光ファイバ製造方法
JP4417995B2 (ja) * 2007-12-06 2010-02-17 三菱電線工業株式会社 ダブルクラッドファイバ及びその加工方法
US7590324B1 (en) * 2008-07-24 2009-09-15 Corning Incorporated Double-clad optical fibers and devices with double-clad optical fibers
CN113126198B (zh) * 2019-12-31 2022-07-05 武汉安扬激光技术股份有限公司 一种大纤芯直径的单模光纤

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0520653A1 (fr) * 1991-06-27 1992-12-30 Hughes Aircraft Company Fibre optique avec faible indice de réfraction
JPH08295524A (ja) * 1995-04-25 1996-11-12 Mitsubishi Cable Ind Ltd ハロゲン化物ガラスファイバ母材の製造方法
US5802236A (en) * 1997-02-14 1998-09-01 Lucent Technologies Inc. Article comprising a micro-structured optical fiber, and method of making such fiber
US5907652A (en) * 1997-09-11 1999-05-25 Lucent Technologies Inc. Article comprising an air-clad optical fiber

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0520653A1 (fr) * 1991-06-27 1992-12-30 Hughes Aircraft Company Fibre optique avec faible indice de réfraction
JPH08295524A (ja) * 1995-04-25 1996-11-12 Mitsubishi Cable Ind Ltd ハロゲン化物ガラスファイバ母材の製造方法
US5802236A (en) * 1997-02-14 1998-09-01 Lucent Technologies Inc. Article comprising a micro-structured optical fiber, and method of making such fiber
US5907652A (en) * 1997-09-11 1999-05-25 Lucent Technologies Inc. Article comprising an air-clad optical fiber

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
K.W. PARK ET AL.: "Observation of fundamental mode cut-off at short wavelength in a holey optical fiber", OPTICAL FIBER COMMUNICATION CONFERENCE 2001 (TUC5-1-TUC5-3), 20 March 2001 (2001-03-20), XP002952451 *
TANYA M. MONRO ET AL.: "New possibilities with holey fibers", OPTICAL FIBER COMMUNICATION CONFERENCE (THG4-1-4-3), vol. 3, 2000, pages 106 - 108, XP000941699 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1571131A2 (fr) * 2004-03-03 2005-09-07 Samsung Electronics Co., Ltd. Procédé de fabrication d'une préfrome pour une fibre optique à trous
EP1571131A3 (fr) * 2004-03-03 2006-03-29 Samsung Electronics Co., Ltd. Procédé de fabrication d'une préfrome pour une fibre optique à trous
CN112408773A (zh) * 2020-10-29 2021-02-26 东北大学 D形光子晶体光纤预制棒及其d形光子晶体光纤拉制方法

Also Published As

Publication number Publication date
JP4080701B2 (ja) 2008-04-23
JP2002277669A (ja) 2002-09-25

Similar Documents

Publication Publication Date Title
US9151889B2 (en) Rare earth doped and large effective area optical fibers for fiber lasers and amplifiers
US9815731B1 (en) Tapered core fiber manufacturing methods
US7107795B2 (en) Method for forming high-density multicore phase-locked fiber laser array
WO2002078138A1 (fr) Fibre a double gainage et procede de production d'une fibre a double gainage
JP2002296440A (ja) 大きな実効断面積を有するフォトニック光ファイバ
JP5102979B2 (ja) レーザー光の出射方法
JP4476900B2 (ja) フォトニッククリスタルファイバ母材の製造方法
US20060120677A1 (en) Optical waveguide, method of its production, and its use
JP3836698B2 (ja) フォトニッククリスタルファイバの製造方法
JP4249121B2 (ja) ダブルクラッドファイバの製造方法
JP4541264B2 (ja) 光ファイバ母材の製造方法および光ファイバの製造方法
WO2011001850A1 (fr) Procédé de fabrication d'une préforme de fibre à bande interdite photonique et procédé de fabrication d'une fibre à bande interdite photonique
KR101927388B1 (ko) 삼중 피복 단일 모드 광섬유
JP4447531B2 (ja) フォトニックバンドギャップファイバとその製造方法
WO2013031484A1 (fr) Fibre
JP4447528B2 (ja) フォトニックバンドギャップファイバとその製造方法
KR100660148B1 (ko) 공기홀을 갖는 광섬유용 모재의 제조 방법
JP2004273581A (ja) 光学装置、及びダブルクラッドファイバの励起方法
JP4447529B2 (ja) フォトニックバンドギャップファイバとその製造方法
JP2006160550A (ja) フォトニッククリスタルファイバとその製造方法、フォトニッククリスタルファイバ製造用プリフォーム
JP2002277647A (ja) ダブルクラッドファイバの製造方法及びダブルクラッドファイバ
US20060008218A1 (en) Method of manufacturing an optical fibre, a preform and an optical fibre
JP4451360B2 (ja) フォトニックバンドギャップファイバとその製造方法
JP2007127929A (ja) フォトニックバンドギャップファイバとその製造方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
122 Ep: pct application non-entry in european phase