WO2010055696A1 - Fibre optique dopée à l’ytterbium, laser à fibre et amplificateur à fibres - Google Patents

Fibre optique dopée à l’ytterbium, laser à fibre et amplificateur à fibres Download PDF

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Publication number
WO2010055696A1
WO2010055696A1 PCT/JP2009/006136 JP2009006136W WO2010055696A1 WO 2010055696 A1 WO2010055696 A1 WO 2010055696A1 JP 2009006136 W JP2009006136 W JP 2009006136W WO 2010055696 A1 WO2010055696 A1 WO 2010055696A1
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core
optical fiber
ytterbium
clad
doped optical
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PCT/JP2009/006136
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English (en)
Japanese (ja)
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中熊映乃
市井健太郎
谷川庄二
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株式会社フジクラ
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Priority claimed from PCT/JP2009/052756 external-priority patent/WO2010055700A1/fr
Application filed by 株式会社フジクラ filed Critical 株式会社フジクラ
Priority to CN200980112786.3A priority Critical patent/CN101999197B/zh
Priority to DK09825949.2T priority patent/DK2352209T3/en
Priority to EP09825949.2A priority patent/EP2352209B1/fr
Priority to CA2721326A priority patent/CA2721326C/fr
Priority to JP2010522121A priority patent/JP5436426B2/ja
Publication of WO2010055696A1 publication Critical patent/WO2010055696A1/fr
Priority to US12/907,622 priority patent/US8363313B2/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
    • H01S3/06716—Fibre compositions or doping with active elements
    • 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
    • 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
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/06—Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
    • 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
    • G02B6/024—Optical fibres with cladding with or without a coating with polarisation maintaining properties
    • 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
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/08—Doped silica-based glasses containing boron or halide
    • C03C2201/10—Doped silica-based glasses containing boron or halide containing boron
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/08—Doped silica-based glasses containing boron or halide
    • C03C2201/12—Doped silica-based glasses containing boron or halide containing fluorine
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/08—Doped silica-based glasses containing boron or halide
    • C03C2201/14—Doped silica-based glasses containing boron or halide containing boron and fluorine
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/20—Doped silica-based glasses containing non-metals other than boron or halide
    • C03C2201/28—Doped silica-based glasses containing non-metals other than boron or halide containing phosphorus
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/30—Doped silica-based glasses containing metals
    • C03C2201/31—Doped silica-based glasses containing metals containing germanium
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/30—Doped silica-based glasses containing metals
    • C03C2201/34—Doped silica-based glasses containing metals containing rare earth metals
    • C03C2201/3488—Ytterbium
    • 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
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/30—Doped silica-based glasses containing metals
    • C03C2201/34—Doped silica-based glasses containing metals containing rare earth metals
    • C03C2201/36—Doped silica-based glasses containing metals containing rare earth metals containing rare earth metals and aluminium, e.g. Er-Al co-doped
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
    • H01S3/06712—Polarising fibre; Polariser
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
    • H01S3/067—Fibre lasers
    • H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
    • H01S3/06729—Peculiar transverse fibre profile
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
    • H01S3/094007—Cladding pumping, i.e. pump light propagating in a clad surrounding the active core
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/1601—Solid materials characterised by an active (lasing) ion
    • H01S3/1603—Solid materials characterised by an active (lasing) ion rare earth
    • H01S3/1618—Solid materials characterised by an active (lasing) ion rare earth ytterbium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/1691—Solid materials characterised by additives / sensitisers / promoters as further dopants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/1691—Solid materials characterised by additives / sensitisers / promoters as further dopants
    • H01S3/1693—Solid materials characterised by additives / sensitisers / promoters as further dopants aluminium

Definitions

  • the present invention relates to an ytterbium-doped optical fiber in which photodarkening is suppressed, and a fiber laser and a fiber amplifier having the optical fiber.
  • rare earth-doped optical fibers are widely used for fiber amplifiers that amplify signal light having the same wavelength as stimulated emission light and fiber lasers that output laser oscillation light having the same wavelength as stimulated emission light. It's being used. And it is desired for fiber amplifiers and fiber lasers to have high and flat gain characteristics and oscillation characteristics in a wider wavelength band. From this point of view, research and development of rare earth-doped optical fibers are being developed.
  • an ytterbium (Yb) doped optical fiber As a rare earth doped optical fiber, for example, an ytterbium (Yb) doped optical fiber is known.
  • This Yb-doped optical fiber provides high power output light with good beam quality.
  • the oscillation wavelength of this output light is about 1 ⁇ m, which is almost the same as that of Nd-YAG, which is one of existing high-power lasers. Therefore, it is expected to be put to practical use as a laser medium for a high-output light source for material processing applications such as welding, marking, and cutting.
  • FIG. 13 is a diagram illustrating a radial cross section and a refractive index distribution of a conventional Yb-doped optical fiber.
  • the Yb-doped optical fiber 110 shown here is a single clad fiber, in which a clad 112 is provided on the outer periphery of the core 111, and a protective coating layer 113 is provided on the outer periphery of the clad 112.
  • the refractive index of the core 111 is higher than the refractive index of the cladding 112 in order to confine the guided light.
  • a refractive index increasing dopant such as germanium (Ge), aluminum (Al), or phosphorus (P) is usually added to the core 111.
  • Yb is added to the core 111 as a dopant having an optical amplification function. Yb is usually added so as to have a substantially uniform concentration distribution in the core 111, but may have a concentration distribution, and may be added to a part of the cladding 112. High power signal light can be obtained by making excitation light incident on such a Yb-doped optical fiber and making signal light incident or by forming a cavity using a fiber Bragg grating or the like.
  • Non-Patent Document 1 has a detailed disclosure about the conditions of an optical waveguide for single mode propagation.
  • Non-Patent Document 1 shows a relationship that should satisfy single mode propagation with respect to numerical aperture (NA) and core diameter.
  • NA numerical aperture
  • the NA needs to be about 0.04 or less.
  • the relationship represented by the following expression (1) is established approximately between the NA and the refractive index of the core.
  • the relative refractive index difference needs to be 0.035% or less.
  • the relative refractive index difference needs to be 0.15% or less.
  • considering the performance as an optical amplification medium it is desired that the amplification optical fiber can output light with higher power.
  • the former has a light transmission cross-sectional area larger than that of the latter. Since (mode field diameter) is small, the power density of light propagating through the core is increased. As a result, it is easy to induce damage to the core glass and optical nonlinear phenomenon due to light. Alternatively, the amplification power during optical transmission is limited. Therefore, from this point of view, a larger core diameter is desirable. From the above, in order to increase the core diameter and propagate the single mode, it is necessary to lower the refractive index of the core.
  • Non-Patent Documents 2 and 3 One factor that deteriorates the characteristics of fiber amplifiers and fiber lasers is an increase in optical fiber loss (photodarkening) caused by pumping light and signal light propagating in the fiber. Due to this increase in loss, the optical amplification efficiency of the rare earth-doped optical fiber, which is an optical amplification medium, gradually decreases. As a result, the output of the fiber amplifier or the fiber laser decreases with time and the life is shortened.
  • Non-Patent Document 2 discloses that photodarkening is suppressed by applying a special manufacturing method called DND (Direct Nanoparticle Deposition).
  • Non-Patent Document 3 discloses that photodarkening is suppressed by adding aluminum to an optical fiber at a high concentration.
  • Non-Patent Document 4 discloses that photodarkening is suppressed by adding phosphorus at a high concentration during the production of an optical fiber.
  • Patent Document 1 discloses that photodarkening is suppressed by adding hydrogen to an optical fiber.
  • Patent Document 2 the addition of rare earth elements, germanium, aluminum, and phosphorus to the core of an optical fiber reduces the difference in refractive index between the core and the cladding, and suppresses recrystallization of the rare earth elements. Is disclosed.
  • Non-Patent Document 2 photodarkening can surely be suppressed as compared with the case of manufacturing by the conventional method, but the suppression effect is still insufficient. Also, the manufacturing method is special, and in principle, this method cannot sufficiently dehydrate. As a result, the OH group is mixed into the optical fiber more than the conventional MCVD method and VAD method. Therefore, in the optical fiber manufactured by this manufacturing method, the loss due to this OH group becomes large. Furthermore, since the size of the fiber preform used for manufacture is limited, the manufacturing cost increases. Therefore, an optical fiber for optical amplification in which photodarkening is suppressed cannot be manufactured at low cost.
  • Non-Patent Document 3 it is necessary to add a large amount of aluminum in order to sufficiently suppress photodarkening. As a result, the refractive index of the core of the optical fiber becomes high.
  • Rare earth doped optical fibers used for fiber type optical amplifiers and fiber lasers are generally used under conditions of single mode propagation or minority mode propagation. Therefore, when the refractive index of the core is high, the core diameter must be relatively small. When the core diameter is small, the effective core cross-sectional area (A eff ) of the optical fiber is small, so that the power density of the propagating light is high and the nonlinear optical effect is likely to appear. That is, there is a problem that wavelength conversion due to the nonlinear optical effect occurs and desired output light cannot be obtained.
  • Non-Patent Document 4 it is necessary to add a large amount of phosphorus in order to sufficiently suppress photodarkening. Also in this case, like the method described in Non-Patent Document 3, the refractive index of the core of the optical fiber becomes high. When the refractive index of the core is high as described above, it is necessary to reduce the core diameter in order to operate the optical fiber in a single mode. However, as described above, the nonlinear optical effect is easily exhibited, and desired output light is generated. There was a problem that it could not be obtained. According to the method described in Patent Document 1, photodarkening can be suppressed, but a hydrogen impregnation step and a light irradiation step are required.
  • Patent Document 2 there is no description regarding suppression of photodarkening, and it is not only possible that photodarkening cannot be sufficiently suppressed only by adding the above elements to the core in the concentration range described in Patent Document 2.
  • the refractive index of the optical fiber increases and the effective core area (A eff ) of the optical fiber decreases, and wavelength conversion due to the nonlinear optical effect may occur, and desired output light may not be obtained.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide an optical fiber that can be manufactured by a conventional method and in which photodarkening is suppressed.
  • the present invention employs the following means in order to solve the above problems and achieve the object.
  • the ytterbium-doped optical fiber of the present invention includes a core containing ytterbium, aluminum, and phosphorus and not containing germanium, and a clad surrounding the core, and converted to ytterbium oxide of the ytterbium in the core.
  • the concentration is 0.09 to 0.68 mol%, and the molar ratio of the phosphorous in terms of diphosphorus pentoxide and the ytterbium oxide in the core is 3 to 30;
  • the molar ratio between the aluminum oxide equivalent concentration and the ytterbium oxide equivalent concentration of the aluminum is 3 to 32, and the molar ratio between the aluminum oxide equivalent concentration and the diphosphorus pentoxide equivalent concentration is 1 to 2.5.
  • the ytterbium-doped optical fiber of the present invention includes a core containing ytterbium, aluminum, phosphorus and germanium, and a clad surrounding the core, and the ytterbium oxide equivalent concentration of the ytterbium in the core is 0.09 to 0.68 mol%, the germanium oxide equivalent concentration of the germanium in the core is 0.1 to 1.1 mol%, and the phosphorus in the core is equivalent to diphosphorus pentoxide
  • the molar ratio of the concentration to the ytterbium oxide equivalent concentration is 3 to 30, the molar ratio of the aluminum equivalent to the aluminum oxide equivalent to the ytterbium oxide equivalent concentration in the core is 3 to 32, and the aluminum oxide
  • the molar ratio of the converted concentration to the diphosphorus pentoxide converted concentration is 1 to 2.5.
  • the germanium oxide equivalent concentration is preferably 0.30 to 0.59 mol%.
  • the core and the clad are made of silica glass.
  • the molar ratio between the diphosphorus pentoxide equivalent concentration and the ytterbium oxide equivalent concentration is 5 to 30, and the aluminum oxide equivalent concentration and the ytterbium oxide equivalent concentration are The molar ratio is preferably 5 to 32.
  • the aluminum oxide equivalent concentration and the diphosphorus pentoxide equivalent concentration are both 8 mol% or less.
  • the relative refractive index difference between the core and the clad is preferably 0.05 to 0.3%.
  • the relative refractive index difference between the core and the clad is 0.1 to 0.25%.
  • the core further contains fluorine and / or boron.
  • the core further contains at least one selected from the group consisting of rare earth elements other than the ytterbium and transition metal elements.
  • the refractive index of the radially inner clad is higher than the refractive index of the outer clad.
  • at least three layers of the clad are provided, the refractive index nc1 of the radially innermost clad, the refractive index nc3 of the outermost clad, the innermost and the innermost clad.
  • the refractive index nc2 of the intermediate cladding between the outer claddings preferably satisfies the relationship of nc1>nc2> nc3.
  • the fiber laser of the present invention has the ytterbium-doped optical fiber described in (1) or (2) as an optical amplification medium.
  • the fiber amplifier of the present invention has the ytterbium-doped optical fiber according to (1) or (2) as an optical amplification medium.
  • the ytterbium-doped optical fiber described in the above (1) or (2) it is possible to provide an inexpensive and large amount of optical fiber that can suppress photodarkening and obtain an excellent optical amplification effect. Further, by using such an optical fiber as an optical amplifying medium, it is possible to provide a fiber laser and a fiber amplifier having low optical output and good optical characteristics at low cost.
  • FIG. 1 is a diagram illustrating a radial cross section and a refractive index distribution of a Yb-doped optical fiber manufactured in Example 1.
  • FIG. 2 is a graph showing the relationship between the amount of loss before and after excitation light irradiation and the difference wavelength in Example 1.
  • FIG. 3 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 2.
  • FIG. 4 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 3.
  • FIG. 1 is a diagram illustrating a radial cross section and a refractive index distribution of a Yb-doped optical fiber manufactured in Example 1.
  • FIG. 2 is a graph showing the relationship between the amount of loss before and after excitation light irradiation and the difference wavelength in Example 1.
  • FIG. 3 is a diagram showing a cross section in the
  • FIG. 5 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 4.
  • FIG. 6 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 5.
  • FIG. 7 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 6.
  • FIG. 8 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 7.
  • FIG. 9 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber produced in Example 8.
  • FIG. 10 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber produced in Example 9.
  • FIG. 11 is a diagram showing a cross section in the radial direction and a refractive index distribution of the Yb-doped optical fiber manufactured in Example 10.
  • FIG. 12 is a graph showing the relationship between the amount of loss before and after excitation light irradiation and the difference wavelength in Comparative Example 2.
  • FIG. 13 is a diagram showing a radial section and a refractive index distribution of a conventional Yb-doped optical fiber.
  • FIG. 14 is a diagram showing a radial cross section and a refractive index distribution of Yb-doped optical fibers of Comparative Examples 9 to 11.
  • the concentration of the additive component shown in the unit of “mol%” is an average value unless otherwise specified in an optical fiber having a refractive index distribution.
  • the Yb-doped optical fiber of the present invention includes a core and a clad surrounding the core.
  • the core contains at least Yb, Al, and P.
  • Yb ytterbium oxide (Yb 2 O 3 ) equivalent concentration in the core (hereinafter sometimes simply referred to as “Yb 2 O 3 equivalent concentration”), P diphosphorus pentoxide (P 2 O 5 ) equivalent Concentration (hereinafter sometimes simply referred to as “P 2 O 5 equivalent concentration”) and Al aluminum oxide (Al 2 O 3 ) equivalent concentration (hereinafter simply referred to as “Al 2 O 3 equivalent concentration”)
  • the Yb 2 O 3 equivalent concentration is 0.09 to 0.68 mol%.
  • the molar ratio of P 2 O 5 equivalent concentration to Yb 2 O 3 equivalent concentration (P 2 O 5 equivalent concentration (mol%) / Yb 2 O 3 equivalent concentration (mol%)) is 3 to 30.
  • the molar ratio of the Al 2 O 3 equivalent concentration to the Yb 2 O 3 equivalent concentration (Al 2 O 3 equivalent concentration (mol%) / Yb 2 O 3 equivalent concentration (mol%)) is 3 to 32.
  • the molar ratio of the Al 2 O 3 equivalent concentration to the P 2 O 5 equivalent concentration (Al 2 O 3 equivalent concentration (mol%) / P 2 O 5 equivalent concentration (mol%)) is 1 to 2.5. is there.
  • Yb is a dopant having an optical amplification effect.
  • Al is a dopant having a refractive index increasing action and a glass crystallization inhibiting action.
  • P is a dopant having a photodarkening suppressing action and a refractive index raising action.
  • P in the core has an action of suppressing photodarkening.
  • the glass in which the core contains only Yb and P, when the refractive index of the core is set to a desired low value, the glass is crystallized. Therefore, this optical fiber cannot be used as an amplification optical fiber.
  • Al by further containing Al in the core, crystallization of the glass can be suppressed even when the refractive index of the core is set to a desired low value while suppressing photodarkening. It is presumed that Al has an action of suppressing crystallization of glass because Yb and P are dispersed in the glass. In addition, it should be noted that the inclusion of both Al and P has the effect of reducing the refractive index.
  • the Yb 2 O 3 equivalent concentration, the P 2 O 5 equivalent concentration, and the Al 2 O 3 equivalent concentration in the core are set within predetermined ranges so as to satisfy the above conditions (A) to (D).
  • suppression of photodarkening and suppression of crystallization of glass can be achieved at a high level, and a more excellent light amplification effect can be obtained.
  • the Yb 2 O 3 equivalent concentration in the core is 0.09 to 0.68 mol%.
  • a sufficient optical amplification effect can be obtained.
  • the Yb-doped optical fiber is applied to a fiber amplifier or a fiber laser, a good amplification effect of approximately 10 dB or more can be obtained.
  • the raise of the refractive index of a core can be suppressed in an allowable range, and the relative refractive index difference ((DELTA)) of a core and a clad can be 0.3% or less.
  • the molar ratio between the P 2 O 5 equivalent concentration and the Yb 2 O 3 equivalent concentration is 3 to 30, and preferably 5 to 30.
  • a higher effect of suppressing photodarkening can be obtained.
  • an increase in loss due to photodarkening can be suppressed to 0.01 dB or less.
  • the relative refractive index difference ( ⁇ ) of the core can be made 0.3% or less, and the optical loss can be made 50 dB / km or less.
  • a fiber is obtained.
  • the molar ratio is 5 to 30, a higher effect of suppressing crystallization of glass can be obtained, and a fiber can be easily manufactured.
  • the molar ratio between the Al 2 O 3 equivalent concentration and the Yb 2 O 3 equivalent concentration is 3 to 32, preferably 5 to 32.
  • the lower limit value or more even if the refractive index of the core is lowered, a higher effect of suppressing crystallization of the glass can be obtained.
  • the upper limit by more than the upper limit, the same effect as when the upper limit or less can be obtained the molar ratio of P 2 O 5 in terms of concentration and Yb 2 O 3 reduced concentration.
  • the molar ratio to 5 to 32, a higher effect of suppressing crystallization of glass can be obtained, and a fiber can be easily manufactured.
  • the molar ratio between the Al 2 O 3 equivalent concentration and the P 2 O 5 equivalent concentration is 1 to 2.5, preferably 1 to 1.8.
  • the lower limit value or more it is possible to obtain a higher effect of suppressing cracking due to fiber strain and crystallization of glass, and a Yb-doped optical fiber can be manufactured stably.
  • the relative refractive index difference ( ⁇ ) of the core can be set to 0.3% or less, and a Yb-doped optical fiber having good characteristics can be obtained.
  • the Al 2 O 3 equivalent concentration in the core is preferably 8 mol% or less. If the Al content is increased more than necessary, the transmission loss of the optical fiber becomes high. By setting the Al content in such a range, the transmission loss is suppressed and a higher light amplification effect can be obtained. Specifically, for example, the optical loss can be reduced to 50 dB / km or less. For the same reason, the P 2 O 5 equivalent concentration in the core is also preferably 8 mol% or less. Then, in the present invention, Al 2 O 3 reduced concentration and terms of P 2 O 5 concentration, it is particularly preferable that both at most 8 mol%.
  • the relative refractive index difference ( ⁇ ) between the core and the clad is preferably 0.05 to 0.3%, more preferably 0.1 to 0.25%.
  • the term "relative refractive index difference between the core and the clad” the refractive index of the core n 1, the refractive index of the cladding in the case of the n 0, the formula: (n 1 -n 0) / n 1 It is a value calculated by x100.
  • “Substantially single mode” means that the waveguide structure is multimode, but is effectively single mode so as to remove higher-order modes by bending or the like.
  • the core and the clad are preferably made of silica glass.
  • Silica glass is not only widely used in general transmission optical fibers, but also can reduce transmission loss and is advantageous for amplifying light with high efficiency.
  • the core may further contain other elements.
  • the function of the Yb-doped optical fiber can be enhanced or different functions can be imparted.
  • a fiber Bragg grating can be easily formed in a Yb-doped optical fiber by containing germanium (hereinafter sometimes abbreviated as Ge) in the core.
  • Ge germanium
  • the control of the refractive index distribution of the core is facilitated by containing one or both of fluorine (hereinafter sometimes abbreviated as F) and boron (hereinafter sometimes abbreviated as B).
  • F fluorine
  • B boron
  • the rare earth element may be a known element used in a conventional Yb-doped optical fiber. Specifically, erbium (Er), thulium (Tm), yttrium (Y), holmium (Ho), samarium (Sm ), Praseodymium (Pr), neodymium (Nd), and the like. What is necessary is just to select the said transition element suitably from a well-known thing according to the objective.
  • the other elements to be contained in the core may be one type or two or more types. These elements may be added to the core by a known method such as an immersion method.
  • the other elements to be contained in the core may be appropriately selected depending on the purpose. And what is necessary is just to set the density
  • the germanium dioxide (GeO 2 ) equivalent concentration is preferably 0.1 to 1.1 mol%, and more preferably 0.3 to 0.59 mol%.
  • a germanium dioxide (GeO 2 ) equivalent concentration of 0.1 to 1.1 mol% corresponds to a Ge concentration of 0.035 to 0.37 mol% in the core.
  • the addition of GeO 2 causes a refractive index increase of about 0.1% at a relative refractive index per mole%.
  • the refractive index of the core is reduced by reducing the aluminum oxide or by relatively reducing the doping amount of ytterbium oxide. Lower.
  • the relative refractive index of the core is increased by about 0.2%, so that one or both of aluminum oxide and ytterbium oxide is decreased by about 0.2%. Therefore, it is necessary to reduce the amount of these dopes. Reducing aluminum oxide makes it impossible to produce optical fiber products due to glass crystallization. In addition, when ytterbium oxide is reduced, the light amplification effect is reduced accordingly. Therefore, it is not desirable to reduce these addition amounts.
  • a ytterbium-doped fiber when a ytterbium-doped fiber is manufactured with a design of a relative refractive index difference of 0.25% between the core and the cladding, the addition of 2 mol% of germanium dioxide as described above will reduce the relative refractive index by 0.2%.
  • the concentration (addition amount) of ytterbium oxide is not originally high only by reducing ytterbium oxide, it is not possible to reduce the relative refractive index by 0.2%. From the above, it is often undesirable to add a large amount of GeO 2 . On the other hand, if the addition amount of GeO 2 is small, the purpose of the addition cannot be sufficiently exhibited. For example, considering that a grating is imparted to this fiber, at least 0.1 mol% of GeO 2 is necessary, and more preferably 0.3 mol% or more.
  • the concentration in terms of diboron trioxide (B 2 O 3 ) is preferably 0.01 to 5 mol%, and more preferably 0.05 to 1 mol%. By setting it to the upper limit of the above range or less, an increase in residual stress is suppressed and a sufficiently strong optical fiber can be obtained. Further, when F is contained, it is preferably 0.05 to 3 mol%, more preferably 0.1 to 1 mol%. The cost can be reduced by setting it to the upper limit value or less of the above range.
  • the concentration in terms of thulium oxide (Tm 2 O 3 ) is preferably 0.01 to 1 mol%, preferably 0.05 to 0. More preferably, it is 5 mol%. By setting it to the upper limit of the above range or less, problems such as concentration quenching can be suppressed.
  • the clad may have a single layer structure or a multi-layer structure such as a two-layer structure or a three-layer structure.
  • a multi-clad fiber such as a double-clad fiber or a triple-clad fiber
  • the excitation light is guided to the cladding, so that the concentration of the excitation light on the core can be suppressed. Therefore, damage to the core glass and optical nonlinear phenomenon can be suppressed, and a higher-power fiber laser or fiber amplifier can be manufactured.
  • a triple clad fiber having higher excitation light utilization efficiency is preferable to a double clad fiber.
  • the shape of the cladding is not particularly limited, and may be appropriately selected according to the purpose.
  • the radial cross-sectional shape is a non-circular shape such as a polygonal shape or a D shape.
  • the stress applying portion can be formed from, for example, a material obtained by adding B 2 O 3 or the like to quartz glass.
  • the refractive index distribution of the core may be adjusted as appropriate according to the purpose.
  • a single-peak step type as illustrated in FIG. 13 may be used.
  • a bell-shaped, concave, dual-shaped, segmented core, double-concave, W-shaped, Any refractive index distribution may be used.
  • the refractive indexes of the core and the clad are preferably adjusted in consideration of the structure of the Yb-doped optical fiber, the desired relative refractive index difference, and the like.
  • the refractive index of the core is preferably higher than the refractive index of the cladding.
  • the refractive index of the radially inner cladding is higher than the refractive index of the radially outer cladding. By doing so, higher output light can be obtained.
  • “radially inner” and “radially outer” refer to the relative positional relationship in the radial direction of the two-layer clad.
  • radially inner cladding and “radially outer cladding” do not necessarily indicate only two-layer cladding of a double-cladding fiber, but any of multi-cladding fibers including three or more claddings. A two-layer cladding is also shown.
  • the refractive index nc1 of the radially innermost cladding, the refractive index nc3 of the outermost cladding, and the intermediate cladding between the innermost and outermost claddings The refractive index nc2 preferably satisfies the relationship of nc1>nc2> nc3. By doing in this way, higher output light can be obtained efficiently.
  • the “intermediate cladding” may be any one disposed between the innermost and outermost claddings.
  • the intermediate cladding may be any one disposed between the innermost and outermost claddings.
  • the triple-clad fiber only the intermediate cladding between the innermost and outermost claddings is shown. It is not a thing.
  • the core diameter is preferably set as appropriate according to the refractive index of the core, but is usually preferably 4 to 50 ⁇ m, and more preferably 8 to 43 ⁇ m.
  • the Yb-doped optical fiber of the present invention can be manufactured by a known method except that a predetermined amount of Yb, Al, and P is added to the core.
  • it can be manufactured by producing a fiber preform by MCVD method, VAD method or the like, spinning the fiber preform so as to have a desired outer diameter, and forming a protective coating layer with UV curable resin or the like on the outer periphery.
  • Yb can be added by a technique of adding to the soot by a liquid immersion method or a technique of spraying droplets in the fiber preform manufacturing process. Further, for example, when the clad shape is non-circular, the fiber preform after the addition of Yb is cut off into a desired shape and then spun.
  • a stress applying portion is provided in the clad
  • a hole is provided in the central axis direction (longitudinal direction of the fiber preform), preferably the inner surface is ground and After polishing to a mirror surface, a stress applying member made of B 2 O 3 —SiO 2 glass produced by MCVD or the like is inserted here, and then spinning is performed.
  • the fiber laser or the fiber amplifier of the present invention has the Yb-doped optical fiber of the present invention as an optical amplification medium. And it can manufacture by the method similar to a well-known fiber laser or fiber amplifier except using the said Yb addition optical fiber of this invention as an amplification medium.
  • a Yb-doped optical fiber that is excellent in the effect of suppressing photodarkening and obtains desired high-output light by applying a known method such as the MCVD method or the VAD method.
  • the size of the fiber preform used at the time of manufacture is not limited. Therefore, Yb-doped optical fibers having excellent characteristics as described above can be provided at low cost and in large quantities. Further, by using such an optical fiber as an optical amplifying medium, it is possible to provide a fiber laser and a fiber amplifier having low optical output and good optical characteristics at low cost.
  • the increase in loss due to photodarkening of the Yb-doped optical fiber was evaluated by the following method. This makes it possible to compare the amount of increase in loss relatively even with optical fibers having different uses and structures.
  • evaluation method of loss increase by photodarkening A Yb-doped optical fiber having a length such that the Yb absorption amount of the core is 340 dB was used, and the core was irradiated with excitation light having a wavelength of 976 nm for 100 minutes so that the amount of incident light was 400 mW. The difference in loss before and after irradiation at a wavelength of 800 nm was defined as “loss increase due to photodarkening”.
  • FIG. 1 is a diagram showing a radial cross section and a refractive index distribution of a Yb-doped optical fiber 1.
  • the Yb-doped optical fiber 1 is a single clad fiber, in which a clad 12 is provided on the outer periphery of the core 11 and a protective coating layer 13 is provided on the outer periphery of the clad 12.
  • the fiber preform was produced by the MCVD method. Yb was added by a liquid immersion method. The fiber preform was spun until the glass outer diameter was about 125 ⁇ m, and a protective coating layer was provided on the outer periphery.
  • FIG. 2 is a graph showing the relationship between the amount of loss before and after excitation light irradiation and the difference wavelength.
  • FIG. 3 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 2.
  • the Yb-doped optical fiber 2 is a single clad fiber, in which a clad 22 is provided on the outer periphery of the core 21 and a protective coating layer 23 is provided on the outer periphery of the clad 22.
  • the fiber preform was produced by the VAD method. Yb was added by a liquid immersion method. The fiber preform was spun until the glass outer diameter was about 125 ⁇ m, and a protective coating layer was provided on the outer periphery.
  • Yb 2 O 3 of the core is 0.38 mol%
  • P 2 O 5 / Yb 2 O 3 is 29.71
  • Al 2 O 3 / Yb 2 O 3 is 31.06
  • Al 2 O 3 / P 2 O 5 was 1.05.
  • the relative refractive index difference ( ⁇ ) of the core was 0.14%. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less. Further, using the obtained Yb-doped optical fiber, a fiber laser was produced, and the temporal change in light output was evaluated. As a result, the decrease in output after 100 hours was 3% or less with a fiber laser having an initial output of 3 W.
  • This output reduction amount includes not only an increase in optical fiber loss but also a cause due to temperature change and measurement variation. Therefore, it was considered that the output decrease due to the loss increase due to photodarkening was 1% or less.
  • Table 1 shows the obtained Yb-doped optical fiber and the evaluation results.
  • FIG. 4 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 3.
  • the Yb-doped optical fiber 3 is a single clad fiber having a core 31 having a three-layer structure, in which a clad 32 is provided on the outer periphery of the core 31 and a protective coating layer 33 is provided on the outer periphery of the clad 32.
  • the core 31 includes a center core 31a, a ring groove 31b provided on the outer periphery of the center core 31a, and a ring core 31c provided on the outer periphery of the ring groove 31b.
  • the fiber preform was produced by the MCVD method.
  • Yb was added by a liquid immersion method.
  • the fiber preform was spun until the glass outer diameter was about 125 ⁇ m, and a protective coating layer was provided on the outer periphery.
  • the core Yb 2 O 3 is 0.09 mol%, P 2 O 5 / Yb 2 O 3 is 22.33, Al 2 O 3 / Yb 2 O 3 is 28.00, Al 2 O 3 / P 2 O 5 Was 1.25.
  • the relative refractive index difference ( ⁇ ) of the core was 0.07%.
  • FIG. 5 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 4.
  • the Yb-doped optical fiber 4 is a double-clad fiber having a clad 42 having a two-layer structure.
  • An inner clad 42a is provided on the outer circumference of the core 41
  • an outer clad 42b is provided on the outer circumference of the inner clad 42a
  • the protective coating layer 43 is provided on the outer periphery of 42b.
  • the cross-sectional shape of the inner cladding 42a is a D shape.
  • the fiber preform was produced by the MCVD method. Yb was added by spraying droplets during soot production. At this point, the cylindrical fiber preform was cut off so that the cross-sectional shape was a D shape as shown in FIG. Then, the obtained fiber preform was spun until the diameter of the circumscribed circle of the glass became about 400 ⁇ m. At this time, a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • the core Yb 2 O 3 is 0.52 mol%, P 2 O 5 / Yb 2 O 3 is 3.04, Al 2 O 3 / Yb 2 O 3 is 3.10, Al 2 O 3 / P 2 O 5 was 1.02.
  • the relative refractive index difference ( ⁇ ) of the core was 0.24%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • FIG. 6 is a diagram illustrating a radial section and a refractive index distribution of the Yb-doped optical fiber 5.
  • the Yb-doped optical fiber 5 is a double-clad fiber having a clad 52 having a two-layer structure, and an inner cladding 52a is provided on the outer periphery of the core 51, an outer cladding 52b is provided on the outer periphery of the inner cladding 52a, and an outer cladding.
  • a protective coating layer 53 is provided on the outer periphery of 52b.
  • a pair of stress applying portions 54 and 54 are provided at positions symmetrical to the core 51.
  • the fiber preform was produced by the VAD method.
  • Yb was added by spraying droplets during soot production.
  • a pair of holes are provided in the central axis direction of the fiber preform so as to be symmetrical with respect to the core, and stress-applied glass prepared by adding boron or the like is inserted therein, and the outer diameter of the glass is about 125 ⁇ m. Spinning until.
  • a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • the core Yb 2 O 3 is 0.33 mol%, P 2 O 5 / Yb 2 O 3 is 3.02, Al 2 O 3 / Yb 2 O 3 is 5.34, Al 2 O 3 / P 2 O 5 was 1.76.
  • the relative refractive index difference ( ⁇ ) of the core was 0.29%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.41. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • FIG. 7 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 6.
  • the Yb-doped optical fiber 6 is a double-clad fiber having a clad 62 having a two-layer structure.
  • An inner clad 62a is provided on the outer circumference of the core 61
  • an outer clad 62b is provided on the outer circumference of the inner clad 62a
  • a protective coating layer 63 is provided on the outer periphery of 62b.
  • the cross-sectional shape of the inner cladding 62a is a regular heptagon, and the core 61, the inner cladding 62a, and the outer cladding 62b are arranged concentrically.
  • the fiber preform was produced by the MCVD method. Yb was added by a liquid immersion method. At this point, the cylindrical fiber preform was cut off so that the cross-sectional shape was a regular heptagon as shown in FIG. The obtained fiber preform was spun until the diameter of the circumscribed circle of the glass became about 420 ⁇ m. At this time, a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • the core Yb 2 O 3 is 0.39 mol%, P 2 O 5 / Yb 2 O 3 is 11.98, Al 2 O 3 / Yb 2 O 3 is 18.34, Al 2 O 3 / P 2 O 5 was 1.53.
  • the relative refractive index difference ( ⁇ ) of the core was 0.13%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • FIG. 8 is a diagram illustrating a radial section and a refractive index distribution of the Yb-doped optical fiber 7.
  • the Yb-doped optical fiber 7 is a triple-clad fiber having a clad 72 having a three-layer structure, an innermost cladding 72a is provided on the outer periphery of the core 71, and an intermediate cladding 72b is provided on the outer periphery of the innermost cladding 72a.
  • the outermost cladding 72c is provided on the outer periphery of the intermediate cladding 72b, and the protective coating layer 73 is provided on the outer periphery of the outermost cladding 72c.
  • the cross section of the intermediate clad 72b is a regular octagon, and the core 71, the innermost clad 72a, the intermediate clad 72b, and the outermost clad 72c are arranged concentrically.
  • the fiber preform was produced by the VAD method. Yb was added by a liquid immersion method. At this time, the cylindrical fiber preform was cut off so that the cross-sectional shape was a regular octagon as shown in FIG. The obtained fiber preform was spun until the diameter of the circumscribed circle of the glass cross section was about 380 ⁇ m. At this time, a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • Yb 2 O 3 of the core is 0.68 mol%, P 2 O 5 / Yb 2 O 3 is 17.79, Al 2 O 3 / Yb 2 O 3 is 18.87, Al 2 O 3 / P 2 O 5 Was 1.06.
  • the relative refractive index difference ( ⁇ ) of the core was 0.28%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.47. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • FIG. 9 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 8.
  • the Yb-doped optical fiber 8 is a triple clad fiber having a two-layer core 81 and a three-layer clad 82.
  • the ring groove 81b is provided on the outer periphery of the center core 81a
  • the innermost cladding 82a is provided on the outer periphery of the ring groove 81b
  • the intermediate cladding 82b is provided on the outer periphery of the innermost cladding 82a
  • the outer periphery of the intermediate cladding 82b is provided on the outer periphery of the intermediate cladding 82b.
  • the outermost clad 82c is provided on the upper surface
  • the protective coating layer 83 is provided on the outer periphery of the outermost clad 82c.
  • the cross-sectional shape of the intermediate clad 82b is a regular heptagon, and the center core 81a, ring groove 81b, innermost clad 82a, intermediate clad 82b, and outermost clad 82c are arranged concentrically.
  • the fiber preform was produced by the MCVD method.
  • Yb was added by a liquid immersion method.
  • the cylindrical fiber preform was cut off so that the cross-sectional shape was a regular heptagon as shown in FIG.
  • the obtained fiber preform was spun until the diameter of the circumscribed circle of the glass became about 400 ⁇ m.
  • a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • the core Yb 2 O 3 is 0.28 mol%, P 2 O 5 / Yb 2 O 3 is 5.79, Al 2 O 3 / Yb 2 O 3 is 7.61, Al 2 O 3 / P 2 O 5 1.31 and GeO 2 was 0.83 mol%.
  • the relative refractive index difference ( ⁇ ) of the core was 0.27%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • FIG. 10 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 9.
  • the Yb-doped optical fiber 9 is a double clad fiber having a clad 92 having a two-layer structure.
  • An inner clad 92a is provided on the outer circumference of the core 91
  • an outer clad 92b is provided on the outer circumference of the inner clad 92a
  • the outer clad is provided on the outer periphery of 92b.
  • a pair of stress applying portions 94 and 94 are provided at positions symmetrical to the core 91. Furthermore, the cross-sectional shape of the inner cladding 92a is a regular octagon, and the core 91, the inner cladding 92a, and the outer cladding 92b are arranged concentrically.
  • the fiber preform was produced by the MCVD method.
  • Yb was added by a liquid immersion method.
  • the cylindrical fiber preform was cut off so that the cross-sectional shape was a regular octagon as shown in FIG.
  • a pair of holes were provided in the direction of the central axis of the fiber preform so as to be symmetrical with respect to the core, and stress-applied glass produced by adding boron or the like was inserted therein.
  • the obtained fiber preform was spun until the diameter of the circumscribed circle of the glass became about 250 ⁇ m.
  • a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • Yb 2 O 3 of the core is 0.60 mol%
  • P 2 O 5 / Yb 2 O 3 is 19.17
  • Al 2 O 3 / Yb 2 O 3 is 20.17
  • Al 2 O 3 / P 2 O 5 A polarization-maintaining optical fiber with 1.05 and F of 0.40 mol% was obtained.
  • the relative refractive index difference ( ⁇ ) of the core was 0.18%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.43. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • FIG. 11 is a diagram illustrating a radial cross section and a refractive index distribution of the Yb-doped optical fiber 10.
  • the Yb-doped optical fiber 10 is a double-clad fiber having a clad 102 having a two-layer structure.
  • An inner clad 102a is provided on the outer circumference of the core 101
  • an outer clad 102b is provided on the outer circumference of the inner clad 102a
  • a protective coating layer 103 is provided on the outer periphery of 102b.
  • the cross-sectional shape of the inner cladding 102a is a regular octagon, and the core 101, the inner cladding 102a, and the outer cladding 102b are arranged concentrically.
  • the fiber preform was produced by the VAD method.
  • Yb was added by a liquid immersion method.
  • the cylindrical fiber preform was cut off so that the cross-sectional shape was a regular octagon as shown in FIG.
  • the obtained fiber preform was spun until the diameter of the circumscribed circle of the glass became about 420 ⁇ m.
  • a polymer clad material having a refractive index lower than that of the glass was applied and cured on the outer periphery of the glass so that excitation light was confined in the glass clad. Further, the outer periphery was coated with a protective UV curable resin.
  • Yb 2 O 3 of the core is 0.26 mol%
  • P 2 O 5 / Yb 2 O 3 is 6.62
  • Al 2 O 3 / Yb 2 O 3 is 9.04
  • GeO 2 was 0.92 mol%
  • F was 0.35 mol%.
  • the relative refractive index difference ( ⁇ ) of the core was 0.21%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less.
  • Example 11 The addition of B in addition to Al, P, and Yb to the core, the addition amount of Al, P, and Yb are different, and the fiber preform that has been cut off so that the cross-sectional shape is D-shaped
  • a double clad fiber was prepared in the same manner as in Example 4 except that spinning was performed until the diameter reached about 125 ⁇ m.
  • the core Yb 2 O 3 is 0.31 mol%
  • P 2 O 5 / Yb 2 O 3 is 22.29
  • Al 2 O 3 / Yb 2 O 3 is 25.23
  • Al 2 O 3 / P 2 O 5 Was 1.13
  • B 2 O 5 was 0.3 mol.
  • the relative refractive index difference ( ⁇ ) of the core was 0.22%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less. Further, using the obtained Yb-doped optical fiber, a fiber laser was produced, and the temporal change in light output was evaluated. As a result, the amount of decrease in output after 100 hours was 1% or less with a pulse fiber laser having an initial output of 20.0 W. This output reduction amount includes not only an increase in optical fiber loss but also a cause due to temperature change and measurement variation. For this reason, it was considered that there was almost no decrease in output due to increased loss due to photodarkening. Table 2 shows the obtained Yb-doped optical fibers and the evaluation results.
  • Tm is added to the core in addition to Al, P, Yb, the addition amount of Al, P, Yb is different, and the fiber preform cut off so that the cross-sectional shape becomes a regular octagonal shape
  • a triple clad fiber was produced in the same manner as in Example 7 except that spinning was performed until the diameter reached about 250 ⁇ m.
  • Tm was added by an immersion method.
  • Yb 2 O 3 of the core is 0.25 mol%
  • P 2 O 5 / Yb 2 O 3 is 25.80
  • Al 2 O 3 / Yb 2 O 3 is 27.52
  • the relative refractive index difference ( ⁇ ) of the core was 0.25%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less. Further, using the obtained Yb-doped optical fiber, a fiber laser was produced, and the temporal change in light output was evaluated. As a result, the output decrease after 100 hours was 3% or less with the pulse fiber laser having an initial output of 15 W.
  • This output reduction amount includes not only an increase in optical fiber loss but also a cause due to temperature change and measurement variation. Therefore, it was considered that the output decrease due to the loss increase due to photodarkening was 1% or less.
  • Table 2 shows the obtained Yb-doped optical fibers and the evaluation results.
  • Example 13 Addition of Nd to the core in addition to Al, P, and Yb, different amounts of addition of Al, P, and Yb, and fiber preforms cut off so that the cross-sectional shape is a regular heptagonal shape.
  • a triple clad fiber was produced in the same manner as in Example 8, except that spinning was performed until the diameter reached about 250 ⁇ m.
  • Nd was added by the immersion method.
  • Yb 2 O 3 of the core is 0.30 mol%
  • P 2 O 5 / Yb 2 O 3 is 13.67
  • Al 2 O 3 / Yb 2 O 3 is 16.53
  • Al 2 O 3 / P 2 O 5 1.21 and Nd 2 O 3 were 0.15 mol.
  • the relative refractive index difference ( ⁇ ) of the core was 0.18%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.43. Almost no increase in loss due to photodarkening was observed in the obtained Yb-doped optical fiber, and the loss increase by the evaluation method was 0.01 dB or less. Further, using the obtained Yb-doped optical fiber, a fiber laser was produced, and the temporal change in light output was evaluated. As a result, the output decrease after 100 hours was 1% or less with the pulsed fiber laser having an initial output of 15.8 W.
  • This output reduction amount includes not only an increase in optical fiber loss but also a cause due to temperature change and measurement variation. Therefore, it was considered that the output decrease due to the loss increase due to photodarkening was 1% or less.
  • Table 3 shows the obtained Yb-doped optical fibers and the evaluation results.
  • Example 1 Example except that Al, Yb, Ge were added to the core, P was not added, the addition amount of Al, Yb was different, and the fiber preform was spun until the glass outer diameter was about 200 ⁇ m.
  • a single clad fiber was produced.
  • the core Yb 2 O 3 was 0.51 mol%
  • Al 2 O 3 / Yb 2 O 3 was 0.39
  • Al 2 O 3 was 0.2 mol%
  • GeO 2 was 0.23 mol%. That is, Al 2 O 3 / Yb 2 O 3 was outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.27%.
  • the obtained Yb-doped optical fiber had a large loss increase due to photodarkening, and the loss increase amount by the evaluation method was 3.8 dB. Therefore, a fiber laser was produced using the obtained Yb-doped optical fiber, and the temporal change in the optical output was evaluated. As a result, the amount of decrease in output after 30 hours with a pulse fiber laser with an initial output of 20 W was 30% or more. Met. Table 3 shows the obtained Yb-doped optical fibers and the evaluation results.
  • the relative refractive index difference ( ⁇ ) of the core was 0.20%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.43.
  • the obtained Yb-doped optical fiber had a large loss increase due to photodarkening, and the loss increase amount by the evaluation method was 10.6 dB.
  • FIG. 12 is a graph showing the relationship between the amount of loss before and after excitation light irradiation and the difference wavelength.
  • the output decrease after 100 hours with a pulse fiber laser with an initial output of 12 W is 50% or more.
  • Table 3 shows the obtained Yb-doped optical fibers and the evaluation results.
  • a double clad fiber was produced in the same manner as in Example 2 except that the addition amounts of Al, P, and Yb were different, and that the polymer clad material was coated and cured to form a double clad structure.
  • Yb 2 O 3 of the core is 0.45 mol%
  • P 2 O 5 / Yb 2 O 3 is 30.7
  • Al 2 O 3 / Yb 2 O 3 is 31.1
  • Al 2 O 3 / P 2 O 5 Was 1.01. That is, P 2 O 5 / Yb 2 O 3 was outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.27%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46.
  • the obtained Yb-doped optical fiber had a large transmission loss and reached about 160 dB / km. Therefore, using the obtained Yb-doped optical fiber, a fiber laser was fabricated and the optical output was evaluated. As a result, the initial output could be realized only up to 6W.
  • Table 4 shows the obtained Yb-doped optical fiber and its evaluation results.
  • a double clad fiber was prepared in the same manner as in Example 5 except that the addition amounts of Al, P, and Yb were different.
  • the core Yb 2 O 3 is 0.22 mol%
  • P 2 O 5 / Yb 2 O 3 is 2.14
  • Al 2 O 3 / Yb 2 O 3 is 4.91
  • Al 2 O 3 / P 2 O 5 was outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.30%.
  • the clad NA obtained from the refractive index difference between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.44.
  • the obtained Yb-doped optical fiber had a large loss increase due to photodarkening, and the loss increase amount by the evaluation method was 1.7 dB. Therefore, a fiber laser was manufactured using the obtained Yb-doped optical fiber, and the temporal change in the optical output was evaluated. As a result, the amount of output decrease after 100 hours with a pulsed fiber laser with an initial output of 12 W was 25% or more. Met. Table 4 shows the obtained Yb-doped optical fiber and its evaluation results.
  • Example 6 A single clad fiber was produced in the same manner as in Example 2 except that the addition amounts of Al, P, and Yb were different.
  • the core Yb 2 O 3 is 0.28 mol%
  • P 2 O 5 / Yb 2 O 3 is 20.29
  • Al 2 O 3 / Yb 2 O 3 is 38.57
  • Al 2 O 3 / P 2 O 5 was 1.90. That is, Al 2 O 3 / Yb 2 O 3 was outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.55%.
  • the loss increase amount of the obtained Yb-doped optical fiber by the evaluation method was about 0.01 dB or less.
  • the mode field diameter of the optical fiber was reduced because of the large relative refractive index difference ( ⁇ ). For this reason, stimulated Raman scattering occurs, and only a fiber laser with an initial output of 5 W can be realized. Further, as a result of producing a fiber laser using the obtained Yb-doped optical fiber and evaluating the temporal change of the optical output, the output decrease after 100 hours is 8% or more with a pulse fiber laser with an initial output of 5 W. Met. Table 4 shows the obtained Yb-doped optical fiber and its evaluation results.
  • a double clad fiber was produced in the same manner as in Example 6 except that the addition amounts of Al, P, and Yb were different.
  • the core Yb 2 O 3 is 0.48 mol%
  • P 2 O 5 / Yb 2 O 3 is 9.02
  • Al 2 O 3 / Yb 2 O 3 is 24.38
  • Al 2 O 3 / P 2 O 5 was 2.70. That is, Al 2 O 3 / P 2 O 5 was outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.85%.
  • the clad NA obtained from the difference in refractive index between the glass clad for guiding the excitation light and the polymer clad for confining the light was about 0.46.
  • the mode field diameter of the optical fiber was small due to the large relative refractive index difference ( ⁇ ). Therefore, stimulated Raman scattering occurs, and only a fiber laser with an initial output of 7 W can be realized.
  • Table 4 shows the obtained Yb-doped optical fiber and its evaluation results.
  • FIG. 14 is a diagram showing a radial section and a refractive index distribution of the Yb-doped optical fiber 120.
  • the Yb-doped optical fiber 120 is a double-clad fiber having a clad 122 having a two-layer structure.
  • the inner clad 122a is provided on the outer circumference of the core 121
  • the outer clad 122b is provided on the outer circumference of the inner clad 122a
  • the outer clad is provided on the outer circumference of the inner clad 122a
  • a protective coating layer 123 is provided on the outer periphery of 122b.
  • Yb 2 O 3 of the core is 1.3 mol%
  • GeO 2 is 1.2 mol%
  • P 2 O 5 / Yb 2 O 3 is 3.77
  • Al 2 O 3 / Yb 2 O 3 is 11.00
  • Al 2 O 3 / P 2 O 5 was 2.92. That is, the Yb 2 O 3 concentration and Al 2 O 3 / P 2 O 5 were outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.45%.
  • the obtained Yb-doped optical fiber is shown in Table 5.
  • the relative refractive index of the core was too high, and the effective core area could not be sufficiently increased.
  • a double clad fiber was produced in the same manner as in Comparative Example 9 except that the addition amounts of Al, P, and Ge were different.
  • Yb 2 O 3 of the core is 1.3 mol%
  • GeO 2 is 4.5 mol%
  • P 2 O 5 / Yb 2 O 3 is 11.54
  • Al 2 O 3 / Yb 2 O 3 is 8.31
  • Al 2 O 3 / P 2 O 5 was 0.72. That is, the Yb 2 O 3 concentration and P 2 O 5 / Yb 2 O 3 were outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.30%.
  • the obtained Yb-doped optical fiber is shown in Table 5.
  • a double clad fiber was prepared in the same manner as in Comparative Example 10 except that the addition amounts of Al and P were different.
  • Yb 2 O 3 of the core is 1.3 mol%
  • GeO 2 is 4.5 mol%
  • P 2 O 5 / Yb 2 O 3 is 23.15
  • Al 2 O 3 / Yb 2 O 3 is 11.00
  • Al 2 O 3 / P 2 O 5 was 0.48. That is, the Yb 2 O 3 concentration and P 2 O 5 / Yb 2 O 3 were outside the scope of the present invention.
  • the relative refractive index difference ( ⁇ ) of the core was 0.48%.
  • the obtained Yb-doped optical fiber is shown in Table 5.
  • the present invention can be used as a laser medium for a high-power light source for material processing applications such as welding, marking, and cutting.

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Abstract

L’invention concerne une fibre optique dopée à l’ytterbium comprenant une âme et une gaine entourant ladite âme qui contient de l’ytterbium, de l’aluminium et du phosphore mais pas de germanium. Dans l’âme, l’ytterbium est contenu selon une quantité de 0,09 à 0,68 % moles en termes de teneur en oxyde d’ytterbium, le rapport molaire entre la teneur en phosphore (en termes de teneur de pentoxyde de phosphore) et la teneur en ytterbium (en termes de teneur d’oxyde d’ytterbium) est de 3 à 30, le rapport molaire entre la teneur en aluminium (en termes de teneur en oxyde d’aluminium) et la teneur en ytterbium (en termes de teneur d’oxyde d’ytterbium) est de 3 à 32, et le rapport molaire entre la teneur en aluminium (en termes de teneur en oxyde d’aluminium) et la teneur en phosphore (en termes de teneur en pentoxyde de phosphore) est compris entre 1 et 2,5.
PCT/JP2009/006136 2008-11-14 2009-11-16 Fibre optique dopée à l’ytterbium, laser à fibre et amplificateur à fibres WO2010055696A1 (fr)

Priority Applications (6)

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CN200980112786.3A CN101999197B (zh) 2008-11-14 2009-11-16 掺镱光纤、光纤激光器及光纤放大器
DK09825949.2T DK2352209T3 (en) 2008-11-14 2009-11-16 OUTERBUM-DOTATED OPTICAL FIBER, FIBER LASER, AND FIBER AMPLIFIER
EP09825949.2A EP2352209B1 (fr) 2008-11-14 2009-11-16 Fibre optique dopée à l'ytterbium, laser à fibre et amplificateur à fibres
CA2721326A CA2721326C (fr) 2008-11-14 2009-11-16 Fibre optique dopee a l'ytterbium, laser a fibre et amplificateur a fibres
JP2010522121A JP5436426B2 (ja) 2008-11-14 2009-11-16 イッテルビウム添加光ファイバ、ファイバレーザ及びファイバアンプ
US12/907,622 US8363313B2 (en) 2008-11-14 2010-10-19 Ytterbium-doped optical fiber, fiber laser, and fiber amplifier

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PCT/JP2009/052756 WO2010055700A1 (fr) 2008-11-14 2009-02-18 Fibre optique dopée à l’ytterbium, laser à fibre et amplificateur à fibres
JPPCT/JP2009/052756 2009-02-18

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011085619A1 (fr) * 2010-01-18 2011-07-21 烽火通信科技股份有限公司 Fibre optique active par champ à large mode et son procédé de fabrication
US8363313B2 (en) 2008-11-14 2013-01-29 Fujikura Ltd. Ytterbium-doped optical fiber, fiber laser, and fiber amplifier
JP2014007255A (ja) * 2012-06-22 2014-01-16 Mitsubishi Cable Ind Ltd 光ファイバ
JP2020045272A (ja) * 2018-09-18 2020-03-26 株式会社フジクラ 光ファイバの製造方法及び光ファイバの製造装置
JP2020079752A (ja) * 2018-11-13 2020-05-28 株式会社フジクラ 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
US11095086B2 (en) 2018-03-30 2021-08-17 Fujikura Ltd. Amplification optical fiber, fiber laser device, and optical resonator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01298043A (ja) * 1988-02-08 1989-12-01 American Teleph & Telegr Co <Att> アルミニウムおよびリン含有シリカ系ガラスを含む物品
JPH09194225A (ja) * 1995-11-22 1997-07-29 Lucent Technol Inc クラッディングポンプファイバとその製造方法
JPH11112070A (ja) 1997-08-07 1999-04-23 Lucent Technol Inc ファイバレーザ
JP2002043660A (ja) * 2000-07-26 2002-02-08 Furukawa Electric Co Ltd:The 光増幅用光ファイバ
JP2003124547A (ja) * 2001-08-21 2003-04-25 Lucent Technol Inc 光ファイバ増幅器
JP2006519495A (ja) * 2003-01-27 2006-08-24 セラムオプテック ゲーエムベーハー マルチクラッド光ファイバーレーザーおよびそれらの製造
JP2007114335A (ja) 2005-10-19 2007-05-10 Fujikura Ltd 光増幅用光ファイバの出力低下抑制方法、光増幅用光ファイバ、光ファイバ増幅器及び光ファイバレーザ

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01298043A (ja) * 1988-02-08 1989-12-01 American Teleph & Telegr Co <Att> アルミニウムおよびリン含有シリカ系ガラスを含む物品
JPH09194225A (ja) * 1995-11-22 1997-07-29 Lucent Technol Inc クラッディングポンプファイバとその製造方法
JPH11112070A (ja) 1997-08-07 1999-04-23 Lucent Technol Inc ファイバレーザ
JP2002043660A (ja) * 2000-07-26 2002-02-08 Furukawa Electric Co Ltd:The 光増幅用光ファイバ
JP2003124547A (ja) * 2001-08-21 2003-04-25 Lucent Technol Inc 光ファイバ増幅器
JP2006519495A (ja) * 2003-01-27 2006-08-24 セラムオプテック ゲーエムベーハー マルチクラッド光ファイバーレーザーおよびそれらの製造
JP2007114335A (ja) 2005-10-19 2007-05-10 Fujikura Ltd 光増幅用光ファイバの出力低下抑制方法、光増幅用光ファイバ、光ファイバ増幅器及び光ファイバレーザ

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
D.J. DIGIOVANNIA ET AL.: "Structure and properties of silica containing aluminum and phosphorus near the A1P04 join", JOURNAL OF NON-CRYSTALLINE SOLIDS, vol. 113, no. ISS.1, 2 November 1989 (1989-11-02), pages 58 - 64, XP024065480 *
M. ENGHOLM: "Preventing photodarkening in ytterbium-doped high power fiber laser; correlation to the UV-transparency of the core glass", THE PROCEEDING OF OPTICS EXPRESS, vol. 16, 2008, pages 1260 - 1268
MING-JUN LI: "Effective Area Limit for Large Mode Area Laser Fibers", THE PROCEEDINGS OF OFC 2008, OTUJ2, 2008
S. TAMMELA ET AL.: "The Potential of Direct Nanoparticle Deposition for the Next Generation of Optical Fibers", THE PROCEEDING OF SPIE PHOTONICS WEST 2006, vol. 6116-16, 2006
T. KITABAYASHI: "Population Inversion Factor Dependence of Photodarkening of Yb-doped Fibers and its Suppression by Highly Aluminum Doping", THE PROCEEDINGS OF OFC 2006, OTHC5, 2006

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8363313B2 (en) 2008-11-14 2013-01-29 Fujikura Ltd. Ytterbium-doped optical fiber, fiber laser, and fiber amplifier
WO2011085619A1 (fr) * 2010-01-18 2011-07-21 烽火通信科技股份有限公司 Fibre optique active par champ à large mode et son procédé de fabrication
JP2014007255A (ja) * 2012-06-22 2014-01-16 Mitsubishi Cable Ind Ltd 光ファイバ
US11095086B2 (en) 2018-03-30 2021-08-17 Fujikura Ltd. Amplification optical fiber, fiber laser device, and optical resonator
JP2020045272A (ja) * 2018-09-18 2020-03-26 株式会社フジクラ 光ファイバの製造方法及び光ファイバの製造装置
WO2020059683A1 (fr) * 2018-09-18 2020-03-26 株式会社フジクラ Procédé de fabrication de fibre optique et appareil de fabrication de fibre optique
US11667560B2 (en) 2018-09-18 2023-06-06 Fujikura Ltd. Manufacturing method for optical fiber and manufacturing apparatus for optical fiber
JP7360270B2 (ja) 2018-09-18 2023-10-12 株式会社フジクラ 光ファイバの製造方法及び光ファイバの製造装置
JP2020079752A (ja) * 2018-11-13 2020-05-28 株式会社フジクラ 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

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