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WO2020045569A1 - Cladding mode light removal structure, laser device, and method for manufacturing cladding mode light removal structure - Google Patents

Cladding mode light removal structure, laser device, and method for manufacturing cladding mode light removal structure Download PDF

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Publication number
WO2020045569A1
WO2020045569A1 PCT/JP2019/033918 JP2019033918W WO2020045569A1 WO 2020045569 A1 WO2020045569 A1 WO 2020045569A1 JP 2019033918 W JP2019033918 W JP 2019033918W WO 2020045569 A1 WO2020045569 A1 WO 2020045569A1
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WIPO (PCT)
Prior art keywords
mode light
cladding
clad
optical fiber
fiber
Prior art date
Application number
PCT/JP2019/033918
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French (fr)
Japanese (ja)
Inventor
康人 千葉
Original Assignee
株式会社フジクラ
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Filing date
Publication date
Application filed by 株式会社フジクラ filed Critical 株式会社フジクラ
Publication of WO2020045569A1 publication Critical patent/WO2020045569A1/en

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    • 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
    • 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
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • 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
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating

Definitions

  • the present invention relates to a cladding mode light removing structure, a laser device, and a method of manufacturing a cladding mode light removing structure, and more particularly to a cladding mode light removing device for removing cladding mode light propagating through a cladding of an optical fiber in a laser device such as a fiber laser. It is about structure.
  • clad mode light is propagated along the clad of the optical fiber without being coupled to the core of the optical fiber.
  • the cladding mode light may reach several hundreds of watts depending on the output of the high-power fiber laser system, in which case the operation of the system may be unstable or the reliability of the system may be reduced. .
  • this high refractive index resin has high light transmittance, its transmittance is not 100%, so that a part of the cladding mode light is absorbed by the high refractive index resin and the high refractive index resin generates heat. With the increase in the output of the entire system, the total amount of the cladding mode light has also increased, and thus the heat generation of such a high refractive index resin has become non-negligible. It has also been practiced to remove only a part in the circumferential direction and control the amount of clad mode light incident on the high refractive index resin to avoid local heat generation of the high refractive index resin.
  • the present invention has been made in view of such problems of the related art, and provides a clad mode light removing structure that can remove clad mode light while suppressing local heat generation by clad mode light at low cost.
  • the first purpose is to do so.
  • a second object of the present invention is to provide a laser device capable of increasing the output.
  • the present invention provides a method for easily manufacturing a clad mode light removing structure capable of removing clad mode light while suppressing local heat generation by clad mode light at a low cost. The purpose of.
  • a clad mode light elimination structure capable of removing clad mode light while suppressing local heat generation by clad mode light at low cost.
  • This cladding mode light removing structure is used to remove cladding mode light propagating in the cladding of the optical fiber.
  • the cladding mode light removing structure, a fiber holding portion holding the optical fiber, and at least a part of the entire circumference of the cladding is exposed from the coating material at a predetermined length along the longitudinal direction of the optical fiber.
  • the optical fiber includes a clad exposed portion and a plurality of high refractive index resin portions disposed on the fiber holding portion so as to be separated from each other in a longitudinal direction of the optical fiber.
  • the plurality of high refractive index resin portions have a refractive index equal to or higher than the refractive index of the cladding. Further, each of the plurality of high refractive index resin portions is formed so as to contact the outer periphery of the clad exposed portion along the circumferential direction of the clad.
  • the “cladding” in the present invention means the outermost cladding when the optical fiber has a plurality of claddings.
  • a laser device capable of increasing the output.
  • This laser device includes a laser light source, an optical fiber connected to the laser light source, and the above-described cladding mode light removing structure.
  • the cladding mode light removing structure is configured to remove cladding mode light propagating in the cladding of the optical fiber connected to the laser light source.
  • a method capable of easily manufacturing a cladding mode light removing structure capable of removing cladding mode light while suppressing local heat generation by cladding mode light at low cost Is done.
  • a cladding mode light removing structure for removing cladding mode light propagating in the cladding of the optical fiber is manufactured.
  • the coating material is removed at a predetermined length along the longitudinal direction of the optical fiber to form a clad exposed portion in which at least a part of the entire circumference of the cladding of the optical fiber is exposed from the coating material.
  • a plurality of high-refractive-index resin portions having a refractive index equal to or higher than the refractive index of the clad are formed on the fiber holding portion so as to be spaced apart in the longitudinal direction, and the clad exposed portion of the optical fiber is formed on the fiber holding portion.
  • the optical fiber is fixed to the fiber holding portion while being in contact with the plurality of high refractive index resin portions.
  • FIG. 1 is a plan view schematically showing a cladding mode light removing structure according to the first embodiment of the present invention.
  • FIG. 2 is a sectional view taken along line AA of FIG.
  • FIG. 3 is a sectional view taken along line BB of FIG.
  • FIG. 4 is a sectional view taken along line CC of FIG.
  • FIG. 5A is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG.
  • FIG. 5B is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG.
  • FIG. 5C is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG.
  • FIG. 5A is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG.
  • FIG. 5B is a cross-sectional view schematically showing a step of manufacturing the cladding
  • FIG. 5D is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG.
  • FIG. 6 is a cross-sectional view schematically showing a cladding mode light removing structure according to the second embodiment of the present invention, and corresponds to a cross section taken along line AA of FIG.
  • FIG. 7 is a cross-sectional view schematically showing a cladding mode light removing structure according to the second embodiment of the present invention, and corresponds to a cross section taken along line CC of FIG.
  • FIG. 8 is a cross-sectional view schematically showing a cladding mode light removing structure according to the third embodiment of the present invention, and corresponds to a cross section taken along line AA of FIG. FIG.
  • FIG. 9 is a cross-sectional view schematically showing a cladding mode light removing structure according to the third embodiment of the present invention, and corresponds to a cross section taken along line CC of FIG.
  • FIG. 10 is a cross-sectional view schematically illustrating a cladding mode light removing structure according to the fourth embodiment of the present invention, and corresponds to a cross section taken along line AA of FIG.
  • FIG. 11 is a cross-sectional view schematically showing a cladding mode light removing structure according to the fourth embodiment of the present invention, and corresponds to a cross section taken along line CC of FIG.
  • FIG. 12 is a schematic diagram showing an example of a fiber laser to which the cladding mode light removing structure according to the present invention can be applied.
  • FIG. 13 is a schematic view showing another example of a fiber laser to which the cladding mode light removing structure according to the present invention can be applied.
  • FIG. 14 is a cross-sectional view schematically showing an amplification optical fiber in
  • FIGS. 1 to 14 the same or corresponding components are denoted by the same reference numerals, and redundant description will be omitted. Also, in FIGS. 1 to 14, the scale and size of each component may be exaggerated or some components may be omitted.
  • FIG. 1 is a plan view schematically showing a cladding mode light removing structure 1 according to a first embodiment of the present invention
  • FIG. 2 is a sectional view taken along line AA of FIG. 1
  • FIG. FIG. 4 is a cross-sectional view taken along line CC of FIG. 1.
  • a cladding mode light removing structure 1 according to the present embodiment includes a fiber holding unit 20 for holding an optical fiber 10, a lid member 30 placed on the fiber holding unit 20, A heat sink (radiator) 40 connected to the holder 20;
  • FIG. 1 shows a state where the lid member 30 is removed for easy understanding.
  • the optical fiber 10 includes a core 11, a clad 14 covering the core 11, and a covering material 12 covering the clad 14, and the covering material 12 has a predetermined shape along the longitudinal direction. Removed in length. As a result, a clad exposed portion 16 where the clad 14 is exposed from the coating material 12 of the optical fiber 10 is formed. In the present embodiment, the clad exposed portion 16 is formed by removing the entire circumference of the coating material 12 at a fixed length along the longitudinal direction. It is exposed from the covering material 12.
  • a fiber groove 22 extending along the axial direction of the optical fiber 10 is formed at the center of the upper surface 21 of the fiber holding portion 20.
  • a part of the optical fiber 10 (cladding exposed portion 16) is accommodated in the space S.
  • the fiber grooves 22 on both sides of the clad exposed portion 16 of the optical fiber 10 are filled with a fixing resin 24 made of RTV (Room Temperature Vulcanizing) resin, UV curable resin, or the like. The fiber 10 is held and fixed to the fiber holding unit 20.
  • a plurality of high refractive index resin portions 50 made of a resin having a refractive index equal to or higher than the refractive index of the cladding 14 of the optical fiber 10 are provided on the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20. Are formed apart from each other in the longitudinal direction.
  • the high-refractive-index resin part 50 is formed so as to contact the outer periphery of the clad exposed part 16 of the optical fiber 10. More specifically, as shown in FIG. 4, each high-refractive-index resin portion 50 is formed so as to contact the outer periphery of the clad exposed portion 16 with a predetermined width along the circumferential direction of the clad 14. .
  • Such a high refractive index resin portion 50 is preferably formed of a material that can be elastically deformed.
  • a resin such as a gel resin or an elastomer material is used as the material of the high refractive index resin portion 50. Can be.
  • the clad exposed portion 16 of the optical fiber 10 is pressed against the high refractive index resin portion 50, whereby the high refractive index resin portion 50 is deformed and the high refractive index resin portion 50 A predetermined length in the direction contacts the outer periphery of the clad exposed portion 16.
  • the circumferential range of the region where the high refractive index resin portion 50 contacts the clad exposed portion 16 is preferably in a range of 25 degrees to 180 degrees around the optical axis of the optical fiber 10.
  • the refractive index of the air is lower than the refractive index of the clad 14 of the optical fiber 10.
  • the refractive index of the high refractive index resin portion 50 in contact with the clad exposed portion 16 is equal to or higher than the refractive index of the clad 14 of the optical fiber 10. Therefore, the cladding mode light propagating through the cladding 14 of the optical fiber 10 is reflected at the interface between the cladding 14 and the air in the cladding exposed portion 16, while having a high refractive index at the interface between the cladding 14 and the high-refractive-index resin portion 50. The light enters the resin portion 50.
  • the clad mode light incident on the high refractive index resin portion 50 is absorbed by the high refractive index resin portion 50 or the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20 and converted into heat. This heat is released from the fiber holding unit 20 to the outside via the heat sink 40.
  • the cladding mode light propagating through the cladding 14 of the optical fiber 10 can be removed from the cladding 14.
  • the clad mode light propagating through the clad 14 of the optical fiber 10 is removed stepwise by each of the high-refractive-index resin portions 50. Therefore, by adjusting the contact area between each high-refractive-index resin portion 50 and the clad exposed portion 16, the amount of clad mode light removed by each high-refractive-index resin portion 50 can be appropriately controlled. .
  • the formation of the high-refractive-index resin portions 50 can be controlled more easily than removing the coating material 12 mechanically as described later, the cladding removed by each of the high-refractive-index resin portions 50 can be controlled. It is easy to control the amount of mode light. Further, since the formation of the high-refractive-index resin portion 50 does not require expensive equipment such as a laser processing device, local heat generation due to cladding mode light can be suppressed at low cost.
  • the area where the high refractive index resin portion 50 located on the upstream side contacts the clad exposed portion 16 is reduced by the height located on the downstream side.
  • the power of the cladding mode light that can be processed is limited by the remaining coating material.
  • the power of the clad mode light that can be processed is not limited by the coating material 12. Therefore, higher power clad mode light can be processed.
  • the covering material 12 of the optical fiber 10 is formed into a predetermined length along the longitudinal direction using a canna-shaped blade.
  • the clad 14 is removed to form a clad exposed portion 16 in which the clad 14 is exposed over the entire circumference.
  • only a part of the entire circumference of the coating material 12 may be removed to form the clad exposed portion 16 in which a part of the entire circumference of the clad 14 is exposed.
  • the refractive index is higher than the refractive index of the clad 14 of the optical fiber 10.
  • the resin is formed in a predetermined pattern using, for example, a dispenser or the like, and the high refractive index resin portion 50 is formed.
  • the pattern of the high-refractive-index resin portion 50 is not particularly limited, a plurality of high-refractive-index resin portions 50 are formed along the longitudinal direction of the fiber groove 22 of the fiber holding portion 20 (the longitudinal direction of the optical fiber 10). The patterns are separated from each other.
  • the patterning of the high-refractive-index resin portion 50 is not limited to the one using a dispenser, and the pattern of the high-refractive-index resin portion 50 may be formed using, for example, a photolithography technique.
  • the optical fiber 10 is arranged along the fiber groove 22 of the fiber holding part 20 so that the clad exposed part 16 of the optical fiber 10 is located above the high refractive index resin part 50.
  • the clad exposed portion 16 is accommodated in the fiber groove 22, and the clad exposed portion 16 is brought into contact with the high refractive index resin portion 50.
  • the high-refractive-index resin portion 50 has elasticity, the high-refractive-index resin portion 50 is deformed by being pressed against the clad exposed portion 16 and comes into contact with the outer periphery of the clad exposed portion 16 along the circumferential direction. Become.
  • a fixing resin 24 is injected into the fiber grooves 22 on both sides in the longitudinal direction of the clad exposed portion 16, and the resin is cured to fix the optical fiber 10 to the fiber holding portion 20. Thereafter, the lid member 30 is placed on the upper part of the fiber holding unit 20 to complete the cladding mode light removing structure 1 shown in FIG.
  • each of the high-refractive-index resin portions 50 can remove the cladding mode light propagating through the clad 14 of the optical fiber 10.
  • the amount can be controlled by adjusting the contact area between each high refractive index resin portion 50 and the clad exposed portion 16. Since the formation of these high-refractive-index resin portions 50 can be controlled more easily than the removal of the coating material 12 of the optical fiber 10, the control of the amount of cladding mode light removed by each of the high-refractive-index resin portions 50 can be controlled. Becomes easier. Therefore, according to the present embodiment, it is possible to easily manufacture the cladding mode light removing structure 1 that can remove the cladding mode light while suppressing local heat generation due to the cladding mode light at low cost.
  • FIG. 6 and 7 are cross-sectional views schematically showing a cladding mode light removing structure 101 according to the second embodiment of the present invention.
  • FIG. 6 corresponds to a cross section taken along line AA of FIG. 1
  • FIG. This corresponds to the cross section taken along line CC of FIG.
  • the lid member 30 is not placed on the fiber holding unit 20, but the low refractive index having a lower refractive index than the refractive index of the clad 14 of the optical fiber 10 is provided in the fiber groove 22 of the fiber holding unit 20. Resin 130 is filled.
  • FIG. 8 and 9 are cross-sectional views schematically showing a cladding mode light removing structure 201 according to the third embodiment of the present invention.
  • FIG. 8 corresponds to a cross section taken along line AA of FIG. 1, and FIG. This corresponds to the cross section taken along line CC of FIG.
  • a resin groove 260 that is deeper than the fiber groove 22 is formed on the bottom surface 22A of the fiber groove 22 of the fiber holding unit 20 in the present embodiment.
  • the resin grooves 260 are formed corresponding to the pattern of the high-refractive-index resin portions 50, and the above-described high-refractive-index resin portions 50 are formed inside the respective resin grooves 260.
  • the high-refractive-index resin portion 50 contacts the fiber holding portion 20 at the bottom surface 22A of the fiber groove 22.
  • the high-refractive-index resin portion 50 is provided inside the resin groove 260.
  • the high refractive index resin portion 50 comes into contact with the fiber holding portion 20 on the bottom surface of the resin groove 260 farther from the optical fiber 10 than the bottom surface 22A of the fiber groove 22. Therefore, the clad mode light can be converted into heat at a position farther from the optical fiber 10 than in the first embodiment, and the influence of the heat generated by the clad mode light on the optical fiber 10 can be reduced.
  • the heat sink 40 is connected to the fiber holding unit 20
  • the clad mode light can be converted into heat at a position closer to the heat sink 40 than in the first embodiment. Can be released to the outside.
  • the amount of the resin applied so as to form a desired pattern while considering the spread of the resin and the like. Must be controlled, and the operation of forming the high refractive index resin portion 50 tends to be complicated.
  • the resin groove 260 corresponding to the pattern of the high-refractive-index resin portion 50 is formed on the bottom surface 22A of the fiber holding portion 20, and therefore, resin is injected into the resin groove 260.
  • the pattern of the high-refractive-index resin portion 50 can be formed relatively easily without considering the spread of the resin.
  • forming such a resin groove 260 in the fiber holding unit 20 is generally easier than controlling the amount of resin to be applied.
  • the high-refractive-index resin portion 50 can be accurately disposed at a predetermined position. Between the contact areas can be suppressed. Therefore, the amount of clad mode light removed by each high refractive index resin portion 50 can be controlled more accurately.
  • the low refractive index resin 130 is filled in the fiber groove 22 of the fiber holding unit 20 without placing the lid member 30 on the fiber holding unit 20. Is also good.
  • FIG. 10 and 11 are cross-sectional views schematically showing a cladding mode light removing structure 301 according to the fourth embodiment of the present invention.
  • FIG. 10 corresponds to a cross section taken along line AA of FIG. 1, and FIG. This corresponds to the cross section taken along line CC of FIG.
  • the clad exposed portion 16 of the first embodiment described above is formed by removing the entire circumference of the coating material 12 at a fixed length along the longitudinal direction. Is formed by removing a part of the entire circumference of the coating material 12 at a fixed length along the longitudinal direction. Thereby, in the clad exposed portion 16, a part of the entire circumference of the clad 14 is exposed from the coating material 12. With such a configuration, the clad exposed portion 16 is reinforced by the remaining portion of the entire circumference of the coating material 12 that has not been removed, so that the mechanical strength of the cladding mode light removing structure 301 can be improved. it can.
  • the low refractive index resin 130 is filled in the fiber groove 22 of the fiber holding unit 20 without placing the lid member 30 on the fiber holding unit 20. Is also good.
  • a resin groove 260 is formed on the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20, and the high refractive index resin portion 50 is formed in the resin groove 260. May be formed.
  • the cladding mode light removing structure in each of the above-described embodiments can be applied to a portion where the cladding mode light is to be removed in a laser device such as a fiber laser.
  • FIG. 12 is a schematic view showing an example of a laser device to which the cladding mode light removing structure according to the present invention can be applied.
  • a laser device 2101 shown in FIG. 12 is configured as a fiber laser, and includes an optical fiber amplifier 2102 as a laser light source and a laser emitting unit 2160.
  • the optical fiber amplifier 2102 includes an optical resonator 2110, a plurality of forward pumping light sources 2120A for introducing pumping light from the front of the optical resonator 2110 to the optical resonator 2110, and a front inline combiner to which these forward pumping light sources 2120A are connected.
  • the optical resonator 2110 includes an amplification optical fiber 2112 having a core doped with rare earth ions such as yttrium (Yb) and erbium (Er), and a high reflection fiber connected to the amplification optical fiber 2112 and the front in-line combiner 2122A.
  • Yb yttrium
  • Er erbium
  • the amplification optical fiber 2112 is configured by a double-clad fiber having an inner cladding formed around a core and an outer cladding formed around the inner cladding.
  • the optical fiber amplifier 2102 includes a first delivery fiber 2130 extending from the rear inline combiner 2122B, and a second delivery fiber 2130 fused to the first delivery fiber 2130 by a fusion splicing part 2140. And a delivery fiber 2150.
  • a laser emitting unit 2160 that emits the laser oscillation light from the amplification optical fiber 2112 toward, for example, the object to be processed is provided.
  • the forward pumping light source 2120A and the backward pumping light source 2120B for example, a high-power multimode semiconductor laser (LD) having a wavelength of 915 nm can be used.
  • the front in-line combiner 2122A and the rear in-line combiner 2122B couple the pump light output from the front pump light source 2120A and the rear pump light source 2120B, respectively, and introduce the combined light into the inner cladding of the amplification optical fiber 2112 described above. As a result, the pump light propagates inside the inner cladding of the amplification optical fiber 2112.
  • HR-FBG2114 is formed by periodically changing the refractive index of an optical fiber, and reflects light in a predetermined wavelength band with a reflectance close to 100%.
  • the OC-FBG2116 is formed by periodically changing the refractive index of the optical fiber, and partially (eg, 10%) of the light in the wavelength band reflected by the HR-FBG2114. It passes through and reflects the rest.
  • the HR-FBG2114, the amplification optical fiber 2112, and the OC-FBG2116 recursively amplify the light in the specific wavelength band between the HR-FBG2114 and the OC-FBG2116 to generate laser oscillation.
  • a resonator 2110 is configured.
  • the above-described cladding mode light removing structure is used, for example, in the optical fiber amplifier 2102, a fusion splicing section 2140 for fusion splicing the first delivery fiber 2130 and the second delivery fiber 2150.
  • a fusion splicing section 2140 for fusion splicing the first delivery fiber 2130 and the second delivery fiber 2150.
  • the pumping light or the amplification optical fiber that is not absorbed by the amplification optical fiber 2112 and propagates through the cladding of the first delivery fiber 2130.
  • the clad mode light such as the laser light leaked from the core of the 2112 is converted into heat, and the heat converted from the clad mode light can be effectively processed.
  • by effectively suppressing the temperature rise of the optical fiber due to the heat generated by the cladding mode light it is possible to prevent the reliability of the optical fiber from being impaired, and to increase the output while securing the reliability of the laser device. It can be realized.
  • the clad mode light removing structure according to the present invention is not limited to the fusion splicing portion 2140, and may be provided at any position where the clad mode light is to be removed.
  • the present invention may be applied to the front inline combiner 2122A and the rear inline combiner 2122B of the optical fiber amplifier 2102.
  • the pump light sources 2120A and 2120B and the combiners 2122A and 2122B are provided on both the HR-FBG2114 side and the OC-FBG2116 side, which is a bidirectional pump type fiber laser.
  • An excitation light source and a combiner may be provided only on one of the HR-FBG2114 side and the OC-FBG2116 side.
  • a mirror can be used instead of the FBG as a reflection unit for causing laser oscillation in the optical resonator 2110.
  • FIG. 13 is a schematic view showing another example of a laser device to which the cladding mode light removing structure according to the present invention can be applied.
  • a laser device 3201 shown in FIG. 13 is configured as a fiber laser, and includes an optical fiber amplifier 3202 as a laser light source and a laser emitting unit 3260.
  • the optical fiber amplifier 3202 combines a signal light generator 3210 for generating signal light, a plurality of pump light sources 3220 for generating pump light, and a signal light from the signal light generator 3210 and a pump light from the pump light source 3220.
  • Optical coupler 3222 for outputting the optical fiber 3122, an amplification optical fiber 3212 having an end connected to the output end 3224 of the optical coupler 3222, and a delivery fiber 3250 fusion-spliced with the amplification optical fiber 3212 at a fusion splicing section 3240. It has. At the downstream end of the delivery fiber 3250, a laser emitting unit 3260 that emits laser oscillation light from the amplification optical fiber 3212 toward, for example, an object to be processed is provided.
  • FIG. 14 is a cross-sectional view schematically showing the amplification optical fiber 3212.
  • the amplification optical fiber 3212 includes a core 3214 that propagates the signal light generated by the signal light generator 3210, an inner cladding 3216 formed around the core 3214, and a periphery of the inner cladding 3216. And a double clad fiber having an outer cladding 3218.
  • the core 3214 is made of, for example, SiO 2 to which a rare earth element such as Yb is added, and serves as a signal light waveguide for transmitting signal light.
  • the inner cladding 3216 is made of a material having a lower refractive index than the core 3214 (for example, SiO 2 ).
  • the outer cladding 3218 is made of a resin having a lower refractive index than the inner cladding 3216 (for example, a low refractive index polymer).
  • the inner cladding 3216 becomes an excitation light waveguide that propagates the excitation light.
  • the signal light from the signal light generator 3210 propagates inside the core 3214 of the amplification optical fiber 3212, and the pump light from the pump light source 3220 propagates inside the inner cladding 3216 and the core 3214 of the amplification optical fiber 3212. .
  • the excitation light propagates through the core 3214
  • the rare-earth element ions added to the core 3214 absorb and excite the excitation light
  • the signal light propagating through the core 3214 is amplified by stimulated emission.
  • the above-described cladding mode light removing structure can be applied to the fusion splicing portion 3240 that fusion-splices the amplification optical fiber 3212 and the delivery fiber 3250.
  • the clad mode light removing structure can be applied to the fusion splicing portion 3240 of the optical fiber amplifier 3202, the pump light not absorbed by the amplification optical fiber 3212 and the leakage from the core of the amplification optical fiber 3212 are prevented.
  • the laser light or other clad mode light can be effectively converted to heat and removed, and this heat can be effectively processed.
  • the clad mode light removing structure according to the present invention is not limited to the fusion splicing part 3240, and can be provided at an arbitrary position where the clad mode light is to be removed.
  • the present invention may be applied to an optical coupler 3222 that combines and outputs the signal light from the signal light generator 3210 and the pump light from the pump light source 3220.
  • the present invention is not limited to the fiber laser, and can be applied to a laser device having a laser light source such as a semiconductor laser. Needless to say.
  • top and bottom used in the present specification are used in relation to the illustrated embodiment, and vary depending on the relative positional relationship of the device. Things.
  • a cladding mode light removing structure capable of removing cladding mode light while suppressing local heat generation by cladding mode light at low cost.
  • This cladding mode light removing structure is used to remove cladding mode light propagating in the cladding of the optical fiber.
  • the cladding mode light removing structure, a fiber holding portion holding the optical fiber, and at least a part of the entire circumference of the cladding is exposed from the coating material at a predetermined length along the longitudinal direction of the optical fiber.
  • the optical fiber includes a clad exposed portion and a plurality of high refractive index resin portions disposed on the fiber holding portion so as to be separated from each other in a longitudinal direction of the optical fiber.
  • the plurality of high refractive index resin portions have a refractive index equal to or higher than the refractive index of the cladding. Further, each of the plurality of high refractive index resin portions is formed so as to contact the outer periphery of the clad exposed portion along the circumferential direction of the clad.
  • the “cladding” in the present invention means the outermost cladding when the optical fiber has a plurality of claddings.
  • the cladding mode light propagating through the cladding of the optical fiber is: At the interface between the clad and the high-refractive-index resin part in the clad exposed part, the light enters the high-refractive-index resin part, is absorbed by the high-refractive-index resin part or the fiber holding part, and is converted into heat.
  • the cladding mode light removing structure may further include a heat radiating unit connected to the fiber holding unit and emitting heat from the fiber holding unit.
  • a plurality of resin grooves in which the plurality of high refractive index resin portions are arranged may be formed in the fiber holding portion.
  • the clad mode light can be converted to heat at a position farther from the optical fiber, so that the heat generated by the clad mode light affects the optical fiber. Can be reduced.
  • the clad mode light can be converted to heat at a position closer to the heat radiating section, so that the heat generated by the clad mode light can be efficiently radiated to the outside. It is possible to do.
  • the exposed clad portion may include a portion where the entire periphery of the clad is exposed from the coating material.
  • the power of the clad mode light that can be processed is not limited by the coating material. Therefore, higher power clad mode light can be processed.
  • the exposed clad portion may include a portion of the entire circumference of the clad that is partially exposed from the coating material.
  • the cladding exposed portion is covered on a part of the entire circumference of the coating material and is reinforced by the cladding, so that the mechanical strength of the cladding mode light removing structure can be improved.
  • a circumferential range of a region where at least one of the plurality of high refractive index resin portions contacts the outer periphery of the clad exposed portion is in a range of 25 degrees to 180 degrees around the optical axis of the optical fiber. Is preferred.
  • a laser device capable of increasing the output.
  • This laser device includes a laser light source, an optical fiber connected to the laser light source, and the above-described cladding mode light removing structure.
  • the cladding mode light removing structure is configured to remove cladding mode light propagating in the cladding of the optical fiber connected to the laser light source.
  • the above-described clad mode light removing structure can remove the clad mode light while suppressing local heat generation due to the clad mode light at low cost, thereby realizing a high output laser device. It is possible to do.
  • a method capable of easily manufacturing a cladding mode light removing structure capable of removing cladding mode light while suppressing local heat generation by cladding mode light at low cost Is done.
  • a cladding mode light removing structure for removing cladding mode light propagating in the cladding of the optical fiber is manufactured.
  • the coating material is removed at a predetermined length along the longitudinal direction of the optical fiber to form a clad exposed portion in which at least a part of the entire circumference of the cladding of the optical fiber is exposed from the coating material.
  • a plurality of high-refractive-index resin portions having a refractive index equal to or higher than the refractive index of the clad are formed on the fiber holding portion so as to be spaced apart in the longitudinal direction, and the clad exposed portion of the optical fiber is formed on the fiber holding portion.
  • the optical fiber is fixed to the fiber holding portion while being in contact with the plurality of high refractive index resin portions.
  • the amount of the cladding mode light removed in each high refractive index resin portion can be controlled by adjusting the contact area between each high refractive index resin portion and the clad exposed portion. Since the formation of the refractive index resin portion can be controlled more easily than the removal of the coating material of the optical fiber, according to the above-described method, the control of the amount of the cladding mode light removed by each of the high refractive index resin portions is performed. Becomes easier. Therefore, it is possible to easily manufacture a clad mode light removing structure capable of removing clad mode light while suppressing local heat generation due to clad mode light at low cost.
  • a heat radiating unit that emits heat from the fiber holding unit may be connected to the fiber holding unit.
  • the clad mode light converted into heat via the high refractive index resin portion can be efficiently emitted from the fiber holding portion to the outside of the heat radiating portion.
  • the plurality of high-refractive-index resin sections may be arranged in a plurality of resin grooves formed in the fiber holding section.
  • the high-refractive-index resin portion can be accurately arranged at a predetermined position. Can be suppressed. Therefore, it is possible to more accurately control the amount of the cladding mode light removed by each high refractive index resin portion.
  • the present invention it is possible to remove the cladding mode light while suppressing the local heat generation due to the cladding mode light propagating through the cladding of the optical fiber at low cost.
  • the present invention is suitably used for a cladding mode light removing structure for removing cladding mode light propagating through the cladding of an optical fiber in a laser device such as a fiber laser.

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Abstract

Provided is a cladding mode light removal structure capable of removing cladding mode light while suppressing local heating due to cladding mode light in an inexpensive manner. This cladding mode light removal structure 1 is used to remove cladding mode light propagating inside a cladding 14 of an optical fiber 10. The cladding mode light removal structure 1 comprises: a fiber-holding portion 20 for holding an optical fiber 10; an exposed cladding portion 16 wherein the entire periphery of a cladding 14 is exposed from a cover material 12 for a prescribed length along the lengthwise direction of the optical fiber 10; and a plurality of high-refractive-index resin portions 50 arranged on the fiber-holding portion 20 and separated from each other in the lengthwise direction of the optical fiber 10. The high-refractive-index resin portions 50 have a refractive index equal to or greater than the refractive index of the cladding 14. Each of the high-refractive-index resin portions 50 is formed so as to make contact with the outer periphery of the exposed cladding portion 16 along the circumferential direction of the cladding 14.

Description

クラッドモード光除去構造、レーザ装置、及びクラッドモード光除去構造の製造方法Cladding mode light removing structure, laser device, and method of manufacturing cladding mode light removing structure
　本発明は、クラッドモード光除去構造、レーザ装置、及びクラッドモード光除去構造の製造方法に係り、特にファイバレーザなどのレーザ装置における光ファイバのクラッドを伝搬するクラッドモード光を除去するクラッドモード光除去構造に関するものである。 The present invention relates to a cladding mode light removing structure, a laser device, and a method of manufacturing a cladding mode light removing structure, and more particularly to a cladding mode light removing device for removing cladding mode light propagating through a cladding of an optical fiber in a laser device such as a fiber laser. It is about structure.
　近年、１０ｋＷを超える高い出力を得ることが可能な高出力ファイバレーザが実用化されている。しかしながら、このような高出力ファイバレーザ中に存在する融着部や出力コンバイナなどにおいては、光ファイバのコアに結合することなく光ファイバのクラッドに沿って伝搬するクラッドモード光が生じる。このクラッドモード光は、高出力ファイバレーザのシステムの出力によっては数１００Ｗに達することがあり、この場合、システムの動作が不安定になったり、システムの信頼性が低下したりする可能性がある。 In recent years, high-output fiber lasers capable of obtaining high output exceeding 10 kW have been put to practical use. However, in a fused portion, an output combiner, and the like existing in such a high-power fiber laser, clad mode light is propagated along the clad of the optical fiber without being coupled to the core of the optical fiber. The cladding mode light may reach several hundreds of watts depending on the output of the high-power fiber laser system, in which case the operation of the system may be unstable or the reliability of the system may be reduced. .
　したがって、このようなクラッドモード光は効果的に除去されて安全に処理される必要があるが、このようなクラッドモード光を処理するための構造として、光ファイバの被覆材の一部を除去してクラッドを露出させ、このクラッドが露出した部分（クラッド露出部）をクラッドの屈折率以上の屈折率を有する高屈折率樹脂で覆った構造が知られている（例えば、特許文献１参照）。このような構成によれば、光ファイバのクラッドを伝搬してきたクラッドモード光が、クラッド露出部において高屈折率樹脂に入射することとなるため、光ファイバのクラッド中からクラッドモード光を除去することができる。 Therefore, such clad mode light needs to be effectively removed and processed safely, but as a structure for processing such clad mode light, a part of the coating material of the optical fiber is removed. There is known a structure in which a clad is exposed by a high refractive index resin having a refractive index equal to or greater than the refractive index of the clad (eg, see Patent Document 1). According to such a configuration, since the clad mode light propagating through the clad of the optical fiber enters the high refractive index resin at the exposed part of the clad, the clad mode light is removed from the clad of the optical fiber. Can be.
　この高屈折率樹脂は高い光透過性を有するものであるが、その透過率は１００％ではないため、クラッドモード光の一部は高屈折率樹脂に吸収されて高屈折率樹脂が発熱する。システム全体の高出力化に伴い、クラッドモード光の総量も増加しているため、このような高屈折率樹脂の発熱は無視できないものとなってきており、特許文献１のように、被覆材の周方向の一部のみを除去して、高屈折率樹脂に入射するクラッドモード光の量を制御して高屈折率樹脂の局所的な発熱を避けることもなされている。 高 Although this high refractive index resin has high light transmittance, its transmittance is not 100%, so that a part of the cladding mode light is absorbed by the high refractive index resin and the high refractive index resin generates heat. With the increase in the output of the entire system, the total amount of the cladding mode light has also increased, and thus the heat generation of such a high refractive index resin has become non-negligible. It has also been practiced to remove only a part in the circumferential direction and control the amount of clad mode light incident on the high refractive index resin to avoid local heat generation of the high refractive index resin.
　このように高屈折率樹脂に入射するクラッドモード光の量を適切に制御するためには、被覆材を除去する領域をサブミリメートルオーダーで微細に調整する必要がある。しかしながら、このような被覆材の除去は機械的に行われることが多く、被覆材をサブミリメートルオーダーで精度良く除去することが難しい。また、レーザ加工により高精度に被覆材を除去することも考えられるが、レーザ光を用いた加工を製造工程に導入することは製造コストの上昇を招く。 領域 In order to appropriately control the amount of cladding mode light incident on the high refractive index resin, it is necessary to finely adjust the region from which the coating material is removed on the order of sub-millimeter. However, such removal of the coating material is often performed mechanically, and it is difficult to remove the coating material with high accuracy on the order of sub-millimeters. Although it is conceivable to remove the coating material with high accuracy by laser processing, introducing processing using laser light into the manufacturing process causes an increase in manufacturing cost.
特許第６０１０５６５号明細書Patent No. 6010565
　本発明は、このような従来技術の問題点に鑑みてなされたもので、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造を提供することを第１の目的とする。 The present invention has been made in view of such problems of the related art, and provides a clad mode light removing structure that can remove clad mode light while suppressing local heat generation by clad mode light at low cost. The first purpose is to do so.
　また、本発明は、高出力化が可能なレーザ装置を提供することを第２の目的とする。 第 A second object of the present invention is to provide a laser device capable of increasing the output.
　さらに、本発明は、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造を容易に製造することができる方法を提供することを第３の目的とする。 Furthermore, the present invention provides a method for easily manufacturing a clad mode light removing structure capable of removing clad mode light while suppressing local heat generation by clad mode light at a low cost. The purpose of.
　本発明の第１の態様によれば、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造が提供される。このクラッドモード光除去構造は、光ファイバのクラッド内を伝搬するクラッドモード光を除去するために用いられる。上記クラッドモード光除去構造は、上記光ファイバを保持するファイバ保持部と、上記光ファイバの長手方向に沿って所定の長さで上記クラッドの全周のうち少なくとも一部を被覆材から露出させたクラッド露出部と、上記ファイバ保持部上に上記光ファイバの長手方向に離間して配置される複数の高屈折率樹脂部を備える。上記複数の高屈折率樹脂部は、上記クラッドの屈折率以上の屈折率を有している。また、上記複数の高屈折率樹脂部のそれぞれは、上記クラッドの周方向に沿って上記クラッド露出部の外周に接触するように形成される。なお、本発明における「クラッド」は、光ファイバが複数のクラッドを有する場合には、最外層のクラッドを意味する。 According to the first aspect of the present invention, there is provided a clad mode light elimination structure capable of removing clad mode light while suppressing local heat generation by clad mode light at low cost. This cladding mode light removing structure is used to remove cladding mode light propagating in the cladding of the optical fiber. The cladding mode light removing structure, a fiber holding portion holding the optical fiber, and at least a part of the entire circumference of the cladding is exposed from the coating material at a predetermined length along the longitudinal direction of the optical fiber. The optical fiber includes a clad exposed portion and a plurality of high refractive index resin portions disposed on the fiber holding portion so as to be separated from each other in a longitudinal direction of the optical fiber. The plurality of high refractive index resin portions have a refractive index equal to or higher than the refractive index of the cladding. Further, each of the plurality of high refractive index resin portions is formed so as to contact the outer periphery of the clad exposed portion along the circumferential direction of the clad. The “cladding” in the present invention means the outermost cladding when the optical fiber has a plurality of claddings.
　本発明の第２の態様によれば、高出力化が可能なレーザ装置が提供される。このレーザ装置は、レーザ光源と、上記レーザ光源に接続された光ファイバと、上述したクラッドモード光除去構造とを備える。上記クラッドモード光除去構造は、上記レーザ光源に接続された上記光ファイバのクラッド内を伝搬するクラッドモード光を除去するように構成されている。 According to the second aspect of the present invention, there is provided a laser device capable of increasing the output. This laser device includes a laser light source, an optical fiber connected to the laser light source, and the above-described cladding mode light removing structure. The cladding mode light removing structure is configured to remove cladding mode light propagating in the cladding of the optical fiber connected to the laser light source.
　本発明の第３の態様によれば、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造を容易に製造することができる方法が提供される。この方法によれば、光ファイバのクラッド内を伝搬するクラッドモード光を除去するクラッドモード光除去構造が製造される。この方法では、光ファイバの長手方向に沿って所定の長さで被覆材を除去して、上記光ファイバのクラッドの全周のうち少なくとも一部を上記被覆材から露出させたクラッド露出部を形成し、上記クラッドの屈折率以上の屈折率を有する複数の高屈折率樹脂部をファイバ保持部上に長手方向に離間させて形成し、上記光ファイバの上記クラッド露出部を上記ファイバ保持部上の上記複数の高屈折率樹脂部に接触させた状態で、上記光ファイバを上記ファイバ保持部に固定する。 According to the third aspect of the present invention, there is provided a method capable of easily manufacturing a cladding mode light removing structure capable of removing cladding mode light while suppressing local heat generation by cladding mode light at low cost. Is done. According to this method, a cladding mode light removing structure for removing cladding mode light propagating in the cladding of the optical fiber is manufactured. In this method, the coating material is removed at a predetermined length along the longitudinal direction of the optical fiber to form a clad exposed portion in which at least a part of the entire circumference of the cladding of the optical fiber is exposed from the coating material. A plurality of high-refractive-index resin portions having a refractive index equal to or higher than the refractive index of the clad are formed on the fiber holding portion so as to be spaced apart in the longitudinal direction, and the clad exposed portion of the optical fiber is formed on the fiber holding portion. The optical fiber is fixed to the fiber holding portion while being in contact with the plurality of high refractive index resin portions.
図１は、本発明の第１の実施形態におけるクラッドモード光除去構造を模式的に示す平面図である。FIG. 1 is a plan view schematically showing a cladding mode light removing structure according to the first embodiment of the present invention. 図２は、図１のＡ－Ａ線断面図である。FIG. 2 is a sectional view taken along line AA of FIG. 図３は、図１のＢ－Ｂ線断面図である。FIG. 3 is a sectional view taken along line BB of FIG. 図４は、図１のＣ－Ｃ線断面図である。FIG. 4 is a sectional view taken along line CC of FIG. 図５Ａは、図１に示すクラッドモード光除去構造を製造する工程を模式的に示す断面図である。FIG. 5A is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG. 図５Ｂは、図１に示すクラッドモード光除去構造を製造する工程を模式的に示す断面図である。FIG. 5B is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG. 図５Ｃは、図１に示すクラッドモード光除去構造を製造する工程を模式的に示す断面図である。FIG. 5C is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG. 図５Ｄは、図１に示すクラッドモード光除去構造を製造する工程を模式的に示す断面図である。FIG. 5D is a cross-sectional view schematically showing a step of manufacturing the cladding mode light removing structure shown in FIG. 図６は、本発明の第２の実施形態におけるクラッドモード光除去構造を模式的に示す断面図であり、図１のＡ－Ａ線断面に対応するものである。FIG. 6 is a cross-sectional view schematically showing a cladding mode light removing structure according to the second embodiment of the present invention, and corresponds to a cross section taken along line AA of FIG. 図７は、本発明の第２の実施形態におけるクラッドモード光除去構造を模式的に示す断面図であり、図１のＣ－Ｃ線断面に対応するものである。FIG. 7 is a cross-sectional view schematically showing a cladding mode light removing structure according to the second embodiment of the present invention, and corresponds to a cross section taken along line CC of FIG. 図８は、本発明の第３の実施形態におけるクラッドモード光除去構造を模式的に示す断面図であり、図１のＡ－Ａ線断面に対応するものである。FIG. 8 is a cross-sectional view schematically showing a cladding mode light removing structure according to the third embodiment of the present invention, and corresponds to a cross section taken along line AA of FIG. 図９は、本発明の第３の実施形態におけるクラッドモード光除去構造を模式的に示す断面図であり、図１のＣ－Ｃ線断面に対応するものである。FIG. 9 is a cross-sectional view schematically showing a cladding mode light removing structure according to the third embodiment of the present invention, and corresponds to a cross section taken along line CC of FIG. 図１０は、本発明の第４の実施形態におけるクラッドモード光除去構造を模式的に示す断面図であり、図１のＡ－Ａ線断面に対応するものである。FIG. 10 is a cross-sectional view schematically illustrating a cladding mode light removing structure according to the fourth embodiment of the present invention, and corresponds to a cross section taken along line AA of FIG. 図１１は、本発明の第４の実施形態におけるクラッドモード光除去構造を模式的に示す断面図であり、図１のＣ－Ｃ線断面に対応するものである。FIG. 11 is a cross-sectional view schematically showing a cladding mode light removing structure according to the fourth embodiment of the present invention, and corresponds to a cross section taken along line CC of FIG. 図１２は、本発明に係るクラッドモード光除去構造を適用可能なファイバレーザの一例を示す模式図である。FIG. 12 is a schematic diagram showing an example of a fiber laser to which the cladding mode light removing structure according to the present invention can be applied. 図１３は、本発明に係るクラッドモード光除去構造を適用可能なファイバレーザの他の例を示す模式図である。FIG. 13 is a schematic view showing another example of a fiber laser to which the cladding mode light removing structure according to the present invention can be applied. 図１４は、図１３に示すファイバレーザにおける増幅用光ファイバを模式的に示す断面図である。FIG. 14 is a cross-sectional view schematically showing an amplification optical fiber in the fiber laser shown in FIG.
　以下、本発明に係るクラッドモード光除去構造及びレーザ装置の実施形態について図１から図１４を参照して詳細に説明する。なお、図１から図１４において、同一又は相当する構成要素には、同一の符号を付して重複した説明を省略する。また、図１から図１４においては、各構成要素の縮尺や寸法が誇張されて示されている場合や一部の構成要素が省略されている場合がある。 Hereinafter, embodiments of a cladding mode light removing structure and a laser device according to the present invention will be described in detail with reference to FIGS. 1 to 14, the same or corresponding components are denoted by the same reference numerals, and redundant description will be omitted. Also, in FIGS. 1 to 14, the scale and size of each component may be exaggerated or some components may be omitted.
　図１は、本発明の第１の実施形態におけるクラッドモード光除去構造１を模式的に示す平面図、図２は、図１のＡ－Ａ線断面図、図３は、図１のＢ－Ｂ線断面図、図４は、図１のＣ－Ｃ線断面図である。図１及び図２に示すように、本実施形態におけるクラッドモード光除去構造１は、光ファイバ１０を保持するファイバ保持部２０と、ファイバ保持部２０上に載置される蓋部材３０と、ファイバ保持部２０に接続されたヒートシンク（放熱部）４０とを備えている。なお、図１では、理解を容易にするため、蓋部材３０を外した状態を示している。 FIG. 1 is a plan view schematically showing a cladding mode light removing structure 1 according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along line CC of FIG. 1. As shown in FIGS. 1 and 2, a cladding mode light removing structure 1 according to the present embodiment includes a fiber holding unit 20 for holding an optical fiber 10, a lid member 30 placed on the fiber holding unit 20, A heat sink (radiator) 40 connected to the holder 20; FIG. 1 shows a state where the lid member 30 is removed for easy understanding.
　図２に示すように、光ファイバ１０は、コア１１と、コア１１を被覆するクラッド１４と、クラッド１４を被覆する被覆材１２とを含んでおり、被覆材１２は長手方向に沿って所定の長さで除去されている。これにより、光ファイバ１０の被覆材１２からクラッド１４が露出するクラッド露出部１６が形成されている。本実施形態では、クラッド露出部１６は、被覆材１２の全周が長手方向に沿って一定の長さで除去されることによって形成されており、クラッド露出部１６においてはクラッド１４の全周が被覆材１２から露出している。 As shown in FIG. 2, the optical fiber 10 includes a core 11, a clad 14 covering the core 11, and a covering material 12 covering the clad 14, and the covering material 12 has a predetermined shape along the longitudinal direction. Removed in length. As a result, a clad exposed portion 16 where the clad 14 is exposed from the coating material 12 of the optical fiber 10 is formed. In the present embodiment, the clad exposed portion 16 is formed by removing the entire circumference of the coating material 12 at a fixed length along the longitudinal direction. It is exposed from the covering material 12.
　図１、図３、及び図４に示すように、ファイバ保持部２０の上面２１の中央には、光ファイバ１０の軸方向に沿って延びるファイバ溝２２が形成されており、このファイバ溝２２内の空間Ｓに光ファイバ１０の一部（クラッド露出部１６）が収容されている。また、光ファイバ１０のクラッド露出部１６を挟む両側のファイバ溝２２には、ＲＴＶ（Room Temperature Vulcanizing）樹脂やＵＶ硬化型樹脂などからなる固定樹脂２４が充填されており、この固定樹脂２４によって光ファイバ１０がファイバ保持部２０に保持及び固定されている。 As shown in FIGS. 1, 3, and 4, a fiber groove 22 extending along the axial direction of the optical fiber 10 is formed at the center of the upper surface 21 of the fiber holding portion 20. A part of the optical fiber 10 (cladding exposed portion 16) is accommodated in the space S. The fiber grooves 22 on both sides of the clad exposed portion 16 of the optical fiber 10 are filled with a fixing resin 24 made of RTV (Room Temperature Vulcanizing) resin, UV curable resin, or the like. The fiber 10 is held and fixed to the fiber holding unit 20.
　図１及び図２に示すように、ファイバ保持部２０のファイバ溝２２の底面２２Ａには、光ファイバ１０のクラッド１４の屈折率以上の屈折率を有する樹脂からなる複数の高屈折率樹脂部５０が長手方向に離間して形成されている。この高屈折率樹脂部５０は、光ファイバ１０のクラッド露出部１６の外周に接触するように形成されている。より具体的には、図４に示すように、それぞれの高屈折率樹脂部５０は、クラッド１４の周方向に沿って所定の幅でクラッド露出部１６の外周に接触するように形成されている。このような高屈折率樹脂部５０は、弾性変形が可能な材料から形成されていることが好ましく、例えばゲル状の樹脂やエラストマー材料からなる樹脂などを高屈折率樹脂部５０の材料として用いることができる。 As shown in FIGS. 1 and 2, a plurality of high refractive index resin portions 50 made of a resin having a refractive index equal to or higher than the refractive index of the cladding 14 of the optical fiber 10 are provided on the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20. Are formed apart from each other in the longitudinal direction. The high-refractive-index resin part 50 is formed so as to contact the outer periphery of the clad exposed part 16 of the optical fiber 10. More specifically, as shown in FIG. 4, each high-refractive-index resin portion 50 is formed so as to contact the outer periphery of the clad exposed portion 16 with a predetermined width along the circumferential direction of the clad 14. . Such a high refractive index resin portion 50 is preferably formed of a material that can be elastically deformed. For example, a resin such as a gel resin or an elastomer material is used as the material of the high refractive index resin portion 50. Can be.
　より具体的には、高屈折率樹脂部５０に光ファイバ１０のクラッド露出部１６が押し付けられており、これにより高屈折率樹脂部５０が変形して高屈折率樹脂部５０がクラッド１４の周方向に所定の長さでクラッド露出部１６の外周に接触している。この高屈折率樹脂部５０がクラッド露出部１６に接触する領域の周方向の範囲は、光ファイバ１０の光軸を中心として２５度～１８０度の範囲であることが好ましい。 More specifically, the clad exposed portion 16 of the optical fiber 10 is pressed against the high refractive index resin portion 50, whereby the high refractive index resin portion 50 is deformed and the high refractive index resin portion 50 A predetermined length in the direction contacts the outer periphery of the clad exposed portion 16. The circumferential range of the region where the high refractive index resin portion 50 contacts the clad exposed portion 16 is preferably in a range of 25 degrees to 180 degrees around the optical axis of the optical fiber 10.
　本実施形態では、ファイバ保持部２０のファイバ溝２２内の空間Ｓには空気が存在しており、空気の屈折率は光ファイバ１０のクラッド１４の屈折率よりも低い。一方で、クラッド露出部１６に接触している高屈折率樹脂部５０の屈折率は光ファイバ１０のクラッド１４の屈折率以上である。したがって、光ファイバ１０のクラッド１４を伝搬するクラッドモード光は、クラッド露出部１６におけるクラッド１４と空気との界面では反射する一方で、クラッド１４と高屈折率樹脂部５０との界面では高屈折率樹脂部５０に入射することとなる。高屈折率樹脂部５０に入射したクラッドモード光は、高屈折率樹脂部５０又はファイバ保持部２０のファイバ溝２２の底面２２Ａで吸収されて熱に変換される。この熱は、ファイバ保持部２０からヒートシンク４０を介して外部に放出される。このようにして、光ファイバ１０のクラッド１４を伝搬するクラッドモード光をクラッド１４から除去することができる。 In the present embodiment, air exists in the space S in the fiber groove 22 of the fiber holding unit 20, and the refractive index of the air is lower than the refractive index of the clad 14 of the optical fiber 10. On the other hand, the refractive index of the high refractive index resin portion 50 in contact with the clad exposed portion 16 is equal to or higher than the refractive index of the clad 14 of the optical fiber 10. Therefore, the cladding mode light propagating through the cladding 14 of the optical fiber 10 is reflected at the interface between the cladding 14 and the air in the cladding exposed portion 16, while having a high refractive index at the interface between the cladding 14 and the high-refractive-index resin portion 50. The light enters the resin portion 50. The clad mode light incident on the high refractive index resin portion 50 is absorbed by the high refractive index resin portion 50 or the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20 and converted into heat. This heat is released from the fiber holding unit 20 to the outside via the heat sink 40. Thus, the cladding mode light propagating through the cladding 14 of the optical fiber 10 can be removed from the cladding 14.
　本実施形態では、複数の高屈折率樹脂部５０が形成されているため、光ファイバ１０のクラッド１４を伝搬するクラッドモード光は、それぞれの高屈折率樹脂部５０で段階的に除去される。したがって、それぞれの高屈折率樹脂部５０とクラッド露出部１６との接触面積を調整することで、それぞれの高屈折率樹脂部５０で除去されるクラッドモード光の量を適切に制御することができる。特に、高屈折率樹脂部５０の形成は、後述するように、機械的に被覆材１２を除去するよりも容易に制御することができるので、それぞれの高屈折率樹脂部５０で除去されるクラッドモード光の量の制御が容易である。また、高屈折率樹脂部５０の形成はレーザ加工装置のような高価な設備を必要としないため、クラッドモード光による局所的な発熱を安価に抑制することが可能である。 In the present embodiment, since the plurality of high-refractive-index resin portions 50 are formed, the clad mode light propagating through the clad 14 of the optical fiber 10 is removed stepwise by each of the high-refractive-index resin portions 50. Therefore, by adjusting the contact area between each high-refractive-index resin portion 50 and the clad exposed portion 16, the amount of clad mode light removed by each high-refractive-index resin portion 50 can be appropriately controlled. . In particular, since the formation of the high-refractive-index resin portions 50 can be controlled more easily than removing the coating material 12 mechanically as described later, the cladding removed by each of the high-refractive-index resin portions 50 can be controlled. It is easy to control the amount of mode light. Further, since the formation of the high-refractive-index resin portion 50 does not require expensive equipment such as a laser processing device, local heat generation due to cladding mode light can be suppressed at low cost.
　また、光ファイバ１０を伝搬するレーザ光は上流側の方がより高パワーであるため、上流側に位置する高屈折率樹脂部５０がクラッド露出部１６に接触する面積を下流側に位置する高屈折率樹脂部５０がクラッド露出部１６に接触する面積よりも小さくすることで、多量のクラッドモード光が局所的に上流側の高屈折率樹脂部５０に放射されることを抑制することができ、局所的な発熱を防止することができる。 In addition, since the laser light propagating through the optical fiber 10 has higher power on the upstream side, the area where the high refractive index resin portion 50 located on the upstream side contacts the clad exposed portion 16 is reduced by the height located on the downstream side. By making the refractive index resin portion 50 smaller than the area in contact with the clad exposed portion 16, a large amount of clad mode light can be suppressed from being locally radiated to the high refractive index resin portion 50 on the upstream side. , Local heat generation can be prevented.
　従来のクラッドモード光除去構造では、除去されるクラッドモード光の量を制御するためにクラッド露出部に被覆材の一部を残さなければならないが、この被覆材はナイロンなどから形成され、他の構成要素に比べて耐熱性が低い。したがって、従来のクラッドモード光除去構造では、処理できるクラッドモード光のパワーは、この残存した被覆材によって制限される。これに対して、本実施形態では、クラッド露出部１６では、被覆材１２が全周にわたって除去されているため、処理できるクラッドモード光のパワーが被覆材１２によって制限を受けることがない。このため、より高パワーのクラッドモード光を処理することができる。 In the conventional cladding mode light removal structure, a part of the coating material must be left on the clad exposed portion in order to control the amount of the cladding mode light to be removed. Low heat resistance compared to components. Therefore, in the conventional cladding mode light removing structure, the power of the cladding mode light that can be processed is limited by the remaining coating material. On the other hand, in the present embodiment, in the cladding exposed portion 16, since the coating material 12 is removed over the entire circumference, the power of the clad mode light that can be processed is not limited by the coating material 12. Therefore, higher power clad mode light can be processed.
　次に、本実施形態におけるクラッドモード光除去構造１を製造する方法について図５Ａから図５Ｄを参照して説明する。上述したクラッドモード光除去構造１を製造する際には、まず、図５Ａに示すように、例えばカンナ状の刃を使って光ファイバ１０の被覆材１２を長手方向に沿って所定の長さで除去し、全周にわたってクラッド１４が露出したクラッド露出部１６を形成する。このとき、後述する実施形態のように、被覆材１２の全周のうち一部のみを除去して、クラッド１４の全周のうち一部が露出したクラッド露出部１６を形成してもよい。 Next, a method of manufacturing the cladding mode light removing structure 1 according to the present embodiment will be described with reference to FIGS. 5A to 5D. When manufacturing the above-described clad mode light removing structure 1, first, as shown in FIG. 5A, for example, the covering material 12 of the optical fiber 10 is formed into a predetermined length along the longitudinal direction using a canna-shaped blade. The clad 14 is removed to form a clad exposed portion 16 in which the clad 14 is exposed over the entire circumference. At this time, as in an embodiment to be described later, only a part of the entire circumference of the coating material 12 may be removed to form the clad exposed portion 16 in which a part of the entire circumference of the clad 14 is exposed.
　クラッド露出部１６を形成する前又は形成した後に、図５Ｂに示すように、ファイバ保持部２０のファイバ溝２２の底面２２Ａ上に、光ファイバ１０のクラッド１４の屈折率よりも高い屈折率を有する樹脂を例えばディスペンサなどを用いて所定のパターンで形成し、高屈折率樹脂部５０を形成する。この高屈折率樹脂部５０のパターンは特に限定されるものではないが、ファイバ保持部２０のファイバ溝２２の長手方向（光ファイバ１０の長手方向）に沿って複数の高屈折率樹脂部５０が互いに離間したパターンとする。この高屈折率樹脂部５０のパターニングは、ディスペンサを用いたものに限られるものではなく、例えばフォトリソグラフィ技術を用いて高屈折率樹脂部５０のパターンを形成してもよい。 Before or after the formation of the clad exposed portion 16, as shown in FIG. 5B, on the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20, the refractive index is higher than the refractive index of the clad 14 of the optical fiber 10. The resin is formed in a predetermined pattern using, for example, a dispenser or the like, and the high refractive index resin portion 50 is formed. Although the pattern of the high-refractive-index resin portion 50 is not particularly limited, a plurality of high-refractive-index resin portions 50 are formed along the longitudinal direction of the fiber groove 22 of the fiber holding portion 20 (the longitudinal direction of the optical fiber 10). The patterns are separated from each other. The patterning of the high-refractive-index resin portion 50 is not limited to the one using a dispenser, and the pattern of the high-refractive-index resin portion 50 may be formed using, for example, a photolithography technique.
　次に、高屈折率樹脂部５０の上方に光ファイバ１０のクラッド露出部１６が位置するように、光ファイバ１０をファイバ保持部２０のファイバ溝２２に沿って配置する。そして、図５Ｃに示すように、クラッド露出部１６をファイバ溝２２内に収容するとともに、クラッド露出部１６を高屈折率樹脂部５０に接触させる。このとき、高屈折率樹脂部５０が弾性を有するため、クラッド露出部１６に押し付けられることによって高屈折率樹脂部５０が変形し、クラッド露出部１６の外周に周方向に沿って接触することとなる。 Next, the optical fiber 10 is arranged along the fiber groove 22 of the fiber holding part 20 so that the clad exposed part 16 of the optical fiber 10 is located above the high refractive index resin part 50. Then, as shown in FIG. 5C, the clad exposed portion 16 is accommodated in the fiber groove 22, and the clad exposed portion 16 is brought into contact with the high refractive index resin portion 50. At this time, since the high-refractive-index resin portion 50 has elasticity, the high-refractive-index resin portion 50 is deformed by being pressed against the clad exposed portion 16 and comes into contact with the outer periphery of the clad exposed portion 16 along the circumferential direction. Become.
　この状態で、図５Ｄに示すように、クラッド露出部１６の長手方向の両側のファイバ溝２２に固定樹脂２４を注入し、これを硬化させることにより光ファイバ１０をファイバ保持部２０に固定する。その後、ファイバ保持部２０の上部に蓋部材３０を載置することで図２に示すクラッドモード光除去構造１が完成する。 (5) In this state, as shown in FIG. 5D, a fixing resin 24 is injected into the fiber grooves 22 on both sides in the longitudinal direction of the clad exposed portion 16, and the resin is cured to fix the optical fiber 10 to the fiber holding portion 20. Thereafter, the lid member 30 is placed on the upper part of the fiber holding unit 20 to complete the cladding mode light removing structure 1 shown in FIG.
　上述したように、それぞれの高屈折率樹脂部５０では光ファイバ１０のクラッド１４を伝搬するクラッドモード光を除去することができるが、それぞれの高屈折率樹脂部５０で除去されるクラッドモード光の量は、それぞれの高屈折率樹脂部５０とクラッド露出部１６との間の接触面積を調整することで制御することができる。これらの高屈折率樹脂部５０の形成は光ファイバ１０の被覆材１２の除去よりも容易に制御することができるので、それぞれの高屈折率樹脂部５０で除去されるクラッドモード光の量の制御が容易になる。したがって、本実施形態によれば、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造１を容易に製造することが可能である。 As described above, each of the high-refractive-index resin portions 50 can remove the cladding mode light propagating through the clad 14 of the optical fiber 10. The amount can be controlled by adjusting the contact area between each high refractive index resin portion 50 and the clad exposed portion 16. Since the formation of these high-refractive-index resin portions 50 can be controlled more easily than the removal of the coating material 12 of the optical fiber 10, the control of the amount of cladding mode light removed by each of the high-refractive-index resin portions 50 can be controlled. Becomes easier. Therefore, according to the present embodiment, it is possible to easily manufacture the cladding mode light removing structure 1 that can remove the cladding mode light while suppressing local heat generation due to the cladding mode light at low cost.
　図６及び図７は、本発明の第２の実施形態におけるクラッドモード光除去構造１０１を模式的に示す断面図であり、図６は図１のＡ－Ａ線断面に対応し、図７は図１のＣ－Ｃ線断面に対応するものである。本実施形態では、ファイバ保持部２０上に蓋部材３０が載置されていないが、ファイバ保持部２０のファイバ溝２２に、光ファイバ１０のクラッド１４の屈折率よりも低い屈折率を有する低屈折率樹脂１３０が充填されている。これにより、光ファイバ１０のクラッド露出部１６及び被覆材１２の一部が低屈折率樹脂１３０に覆われ、ファイバ溝２２の底面２２Ａに形成された高屈折率樹脂部５０も低屈折率樹脂１３０に覆われる。このような構成によっても第１の実施形態と同様の効果を得ることができる。 6 and 7 are cross-sectional views schematically showing a cladding mode light removing structure 101 according to the second embodiment of the present invention. FIG. 6 corresponds to a cross section taken along line AA of FIG. 1, and FIG. This corresponds to the cross section taken along line CC of FIG. In the present embodiment, the lid member 30 is not placed on the fiber holding unit 20, but the low refractive index having a lower refractive index than the refractive index of the clad 14 of the optical fiber 10 is provided in the fiber groove 22 of the fiber holding unit 20. Resin 130 is filled. As a result, a part of the clad exposed portion 16 and the coating material 12 of the optical fiber 10 are covered with the low refractive index resin 130, and the high refractive index resin portion 50 formed on the bottom surface 22 </ b> A of the fiber groove 22 also has the low refractive index resin 130. Covered in. With such a configuration, the same effect as that of the first embodiment can be obtained.
　図８及び図９は、本発明の第３の実施形態におけるクラッドモード光除去構造２０１を模式的に示す断面図であり、図８は図１のＡ－Ａ線断面に対応し、図９は図１のＣ－Ｃ線断面に対応するものである。本実施形態におけるファイバ保持部２０のファイバ溝２２の底面２２Ａには、ファイバ溝２２よりもさらに深くなった樹脂溝２６０が形成されている。この樹脂溝２６０は、高屈折率樹脂部５０のパターンに対応して形成されており、それぞれの樹脂溝２６０の内部に上述した高屈折率樹脂部５０が形成されている。 8 and 9 are cross-sectional views schematically showing a cladding mode light removing structure 201 according to the third embodiment of the present invention. FIG. 8 corresponds to a cross section taken along line AA of FIG. 1, and FIG. This corresponds to the cross section taken along line CC of FIG. A resin groove 260 that is deeper than the fiber groove 22 is formed on the bottom surface 22A of the fiber groove 22 of the fiber holding unit 20 in the present embodiment. The resin grooves 260 are formed corresponding to the pattern of the high-refractive-index resin portions 50, and the above-described high-refractive-index resin portions 50 are formed inside the respective resin grooves 260.
　上述した第１の実施形態では、高屈折率樹脂部５０はファイバ溝２２の底面２２Ａでファイバ保持部２０に接触するが、本実施形態では、樹脂溝２６０の内部に高屈折率樹脂部５０を形成することで、高屈折率樹脂部５０は、ファイバ溝２２の底面２２Ａよりも光ファイバ１０から離れた樹脂溝２６０の底面でファイバ保持部２０に接触することとなる。したがって、第１の実施形態よりも光ファイバ１０から離れた位置でクラッドモード光を熱に変換することができることとなり、クラッドモード光により生じる熱が光ファイバ１０に与える影響を低減することができる。また、ファイバ保持部２０にヒートシンク４０を接続する場合には、第１の実施形態よりもヒートシンク４０に近い位置でクラッドモード光を熱に変換することができるので、クラッドモード光により生じる熱を効率的に外部に放出することができる。 In the above-described first embodiment, the high-refractive-index resin portion 50 contacts the fiber holding portion 20 at the bottom surface 22A of the fiber groove 22. In the present embodiment, the high-refractive-index resin portion 50 is provided inside the resin groove 260. By forming, the high refractive index resin portion 50 comes into contact with the fiber holding portion 20 on the bottom surface of the resin groove 260 farther from the optical fiber 10 than the bottom surface 22A of the fiber groove 22. Therefore, the clad mode light can be converted into heat at a position farther from the optical fiber 10 than in the first embodiment, and the influence of the heat generated by the clad mode light on the optical fiber 10 can be reduced. When the heat sink 40 is connected to the fiber holding unit 20, the clad mode light can be converted into heat at a position closer to the heat sink 40 than in the first embodiment. Can be released to the outside.
　また、上述した第１の実施形態では、高屈折率樹脂部５０をファイバ溝２２の底面２２Ａに形成する際に、樹脂の広がりなどを考慮しながら所望のパターンとなるように塗布する樹脂の量を制御する必要があり、高屈折率樹脂部５０を形成する作業が煩雑になりやすい。これに対して、本実施形態では、ファイバ保持部２０の底面２２Ａに高屈折率樹脂部５０のパターンに対応した樹脂溝２６０が形成されているため、この樹脂溝２６０の内部に樹脂を注入することで、樹脂の広がりなどを考慮することなく比較的簡単に高屈折率樹脂部５０のパターンを形成することができる。また、このような樹脂溝２６０をファイバ保持部２０に形成することは、一般的に、塗布する樹脂の量を制御することよりも簡単である。また、樹脂溝２６０に高屈折率樹脂部５０を配置することで、高屈折率樹脂部５０を所定の位置に正確に配置することができるので、高屈折率樹脂部５０とクラッド露出部１６との間の接触面積のばらつきを抑制することができる。したがって、それぞれの高屈折率樹脂部５０で除去されるクラッドモード光の量をより正確に制御することができる。 In the first embodiment described above, when the high refractive index resin portion 50 is formed on the bottom surface 22A of the fiber groove 22, the amount of the resin applied so as to form a desired pattern while considering the spread of the resin and the like. Must be controlled, and the operation of forming the high refractive index resin portion 50 tends to be complicated. On the other hand, in the present embodiment, the resin groove 260 corresponding to the pattern of the high-refractive-index resin portion 50 is formed on the bottom surface 22A of the fiber holding portion 20, and therefore, resin is injected into the resin groove 260. Thus, the pattern of the high-refractive-index resin portion 50 can be formed relatively easily without considering the spread of the resin. In addition, forming such a resin groove 260 in the fiber holding unit 20 is generally easier than controlling the amount of resin to be applied. In addition, by disposing the high-refractive-index resin portion 50 in the resin groove 260, the high-refractive-index resin portion 50 can be accurately disposed at a predetermined position. Between the contact areas can be suppressed. Therefore, the amount of clad mode light removed by each high refractive index resin portion 50 can be controlled more accurately.
　なお、本実施形態において、第２の実施形態のように、ファイバ保持部２０上に蓋部材３０を載置せずに、ファイバ保持部２０のファイバ溝２２に低屈折率樹脂１３０を充填してもよい。 In this embodiment, unlike the second embodiment, the low refractive index resin 130 is filled in the fiber groove 22 of the fiber holding unit 20 without placing the lid member 30 on the fiber holding unit 20. Is also good.
　図１０及び図１１は、本発明の第４の実施形態におけるクラッドモード光除去構造３０１を模式的に示す断面図であり、図１０は図１のＡ－Ａ線断面に対応し、図１１は図１のＣ－Ｃ線断面に対応するものである。上述した第１の実施形態のクラッド露出部１６は、被覆材１２の全周が長手方向に沿って一定の長さで除去されることによって形成されているが、本実施形態におけるクラッド露出部１６は、被覆材１２の全周のうち一部が長手方向に沿って一定の長さで除去されることによって形成されている。これにより、クラッド露出部１６においてはクラッド１４の全周のうち一部が被覆材１２から露出することとなる。このような構成とすることで、被覆材１２の全周のうち除去されずに残った部分によってクラッド露出部１６が補強されるため、クラッドモード光除去構造３０１の機械的強度を向上させることができる。 10 and 11 are cross-sectional views schematically showing a cladding mode light removing structure 301 according to the fourth embodiment of the present invention. FIG. 10 corresponds to a cross section taken along line AA of FIG. 1, and FIG. This corresponds to the cross section taken along line CC of FIG. The clad exposed portion 16 of the first embodiment described above is formed by removing the entire circumference of the coating material 12 at a fixed length along the longitudinal direction. Is formed by removing a part of the entire circumference of the coating material 12 at a fixed length along the longitudinal direction. Thereby, in the clad exposed portion 16, a part of the entire circumference of the clad 14 is exposed from the coating material 12. With such a configuration, the clad exposed portion 16 is reinforced by the remaining portion of the entire circumference of the coating material 12 that has not been removed, so that the mechanical strength of the cladding mode light removing structure 301 can be improved. it can.
　なお、本実施形態において、第２の実施形態のように、ファイバ保持部２０上に蓋部材３０を載置せずに、ファイバ保持部２０のファイバ溝２２に低屈折率樹脂１３０を充填してもよい。これに加えて、あるいはこれに代えて、第３の実施形態のように、ファイバ保持部２０のファイバ溝２２の底面２２Ａに樹脂溝２６０を形成し、この樹脂溝２６０に高屈折率樹脂部５０を形成してもよい。 In this embodiment, unlike the second embodiment, the low refractive index resin 130 is filled in the fiber groove 22 of the fiber holding unit 20 without placing the lid member 30 on the fiber holding unit 20. Is also good. In addition to or instead of this, as in the third embodiment, a resin groove 260 is formed on the bottom surface 22A of the fiber groove 22 of the fiber holding portion 20, and the high refractive index resin portion 50 is formed in the resin groove 260. May be formed.
　上述した各実施形態におけるクラッドモード光除去構造は、ファイバレーザなどのレーザ装置においてクラッドモード光を除去したい箇所に適用することができる。 ク ラ ッ ド The cladding mode light removing structure in each of the above-described embodiments can be applied to a portion where the cladding mode light is to be removed in a laser device such as a fiber laser.
　図１２は、本発明に係るクラッドモード光除去構造を適用可能なレーザ装置の一例を示す模式図である。図１２に示すレーザ装置２１０１は、ファイバレーザとして構成されており、レーザ光源としての光ファイバ増幅器２１０２とレーザ出射部２１６０とを備えている。光ファイバ増幅器２１０２は、光共振器２１１０と、光共振器２１１０の前方から光共振器２１１０に励起光を導入する複数の前方励起光源２１２０Ａと、これらの前方励起光源２１２０Ａが接続された前方インラインコンバイナ２１２２Ａと、光共振器２１１０の後方から光共振器２１１０に励起光を導入する複数の後方励起光源２１２０Ｂと、これらの後方励起光源２１２０Ｂが接続された後方インラインコンバイナ２１２２Ｂとを備えている。光共振器２１１０は、イットリウム（Ｙｂ）やエルビウム（Ｅｒ）などの希土類イオンが添加されたコアを有する増幅用光ファイバ２１１２と、増幅用光ファイバ２１１２及び前方インラインコンバイナ２１２２Ａと接続される高反射ファイバブラッググレーディング（High Reflectivity Fiber Bragg Grating（ＨＲ－ＦＢＧ））２１１４と、増幅用光ファイバ２１１２及び後方インラインコンバイナ２１２２Ｂと接続される低反射ファイバブラッググレーディング（Output Coupler Fiber Bragg Grating（ＯＣ－ＦＢＧ））２１１６とから構成されている。例えば、増幅用光ファイバ２１１２は、コアの周囲に形成された内側クラッドと、内側クラッドの周囲に形成された外側クラッドとを有するダブルクラッドファイバによって構成される。 FIG. 12 is a schematic view showing an example of a laser device to which the cladding mode light removing structure according to the present invention can be applied. A laser device 2101 shown in FIG. 12 is configured as a fiber laser, and includes an optical fiber amplifier 2102 as a laser light source and a laser emitting unit 2160. The optical fiber amplifier 2102 includes an optical resonator 2110, a plurality of forward pumping light sources 2120A for introducing pumping light from the front of the optical resonator 2110 to the optical resonator 2110, and a front inline combiner to which these forward pumping light sources 2120A are connected. 2122A, a plurality of rear pump light sources 2120B for introducing pump light into the optical resonator 2110 from behind the optical resonator 2110, and a rear inline combiner 2122B to which the rear pump light sources 2120B are connected. The optical resonator 2110 includes an amplification optical fiber 2112 having a core doped with rare earth ions such as yttrium (Yb) and erbium (Er), and a high reflection fiber connected to the amplification optical fiber 2112 and the front in-line combiner 2122A. Bragg grading (High Reflectivity Fiber Bragg Grating (HR-FBG)) 2114, and low reflection fiber Bragg grading (Output Coupler Fiber Bragg Grating (OC-FBG)) 2116 connected to the amplification optical fiber 2112 and the rear inline combiner 2122B. It is composed of For example, the amplification optical fiber 2112 is configured by a double-clad fiber having an inner cladding formed around a core and an outer cladding formed around the inner cladding.
　また、図１２に示すように、光ファイバ増幅器２１０２は、後方インラインコンバイナ２１２２Ｂから延びる第１のデリバリファイバ２１３０と、この第１のデリバリファイバ２１３０と融着接続部２１４０で融着接続される第２のデリバリファイバ２１５０とをさらに有している。この第２のデリバリファイバ２１５０の下流側の端部には増幅用光ファイバ２１１２からのレーザ発振光を例えば被処理物に向けて出射するレーザ出射部２１６０が設けられている。 As shown in FIG. 12, the optical fiber amplifier 2102 includes a first delivery fiber 2130 extending from the rear inline combiner 2122B, and a second delivery fiber 2130 fused to the first delivery fiber 2130 by a fusion splicing part 2140. And a delivery fiber 2150. At the downstream end of the second delivery fiber 2150, a laser emitting unit 2160 that emits the laser oscillation light from the amplification optical fiber 2112 toward, for example, the object to be processed is provided.
　前方励起光源２１２０Ａ及び後方励起光源２１２０Ｂとしては、例えば、波長９１５ｎｍの高出力マルチモード半導体レーザ（ＬＤ）を用いることができる。前方インラインコンバイナ２１２２Ａ及び後方インラインコンバイナ２１２２Ｂは、それぞれ前方励起光源２１２０Ａ及び後方励起光源２１２０Ｂから出力される励起光を結合して上述した増幅用光ファイバ２１１２の内側クラッドに導入するものである。これにより、増幅用光ファイバ２１１２の内側クラッドの内部を励起光が伝搬する。 と し て As the forward pumping light source 2120A and the backward pumping light source 2120B, for example, a high-power multimode semiconductor laser (LD) having a wavelength of 915 nm can be used. The front in-line combiner 2122A and the rear in-line combiner 2122B couple the pump light output from the front pump light source 2120A and the rear pump light source 2120B, respectively, and introduce the combined light into the inner cladding of the amplification optical fiber 2112 described above. As a result, the pump light propagates inside the inner cladding of the amplification optical fiber 2112.
　ＨＲ－ＦＢＧ２１１４は、周期的に光ファイバの屈折率を変化させて形成されるもので、所定の波長帯の光を１００％に近い反射率で反射するものである。ＯＣ－ＦＢＧ２１１６は、ＨＲ－ＦＢＧ２１１４と同様に、周期的に光ファイバの屈折率を変化させて形成されるもので、ＨＲ－ＦＢＧ２１１４で反射される波長帯の光の一部（例えば１０％）を通過させ、残りを反射するものである。このように、ＨＲ－ＦＢＧ２１１４と増幅用光ファイバ２１１２とＯＣ－ＦＢＧ２１１６とによって、ＨＲ－ＦＢＧ２１１４とＯＣ－ＦＢＧ２１１６との間で特定の波長帯の光を再帰的に増幅してレーザ発振を生じさせる光共振器２１１０が構成される。 HR-FBG2114 is formed by periodically changing the refractive index of an optical fiber, and reflects light in a predetermined wavelength band with a reflectance close to 100%. Like the HR-FBG2114, the OC-FBG2116 is formed by periodically changing the refractive index of the optical fiber, and partially (eg, 10%) of the light in the wavelength band reflected by the HR-FBG2114. It passes through and reflects the rest. As described above, the HR-FBG2114, the amplification optical fiber 2112, and the OC-FBG2116 recursively amplify the light in the specific wavelength band between the HR-FBG2114 and the OC-FBG2116 to generate laser oscillation. A resonator 2110 is configured.
　このような構成のレーザ装置２１０１において、上述したクラッドモード光除去構造を、例えば、光ファイバ増幅器２１０２において第１のデリバリファイバ２１３０と第２のデリバリファイバ２１５０とを融着接続する融着接続部２１４０に適用することができる。このように、融着接続部２１４０にクラッドモード光除去構造を適用することで、増幅用光ファイバ２１１２にて吸収されずに第１のデリバリファイバ２１３０のクラッドを伝搬する励起光や増幅用光ファイバ２１１２のコアから漏れ出たレーザ光などのクラッドモード光が熱に変換され、クラッドモード光から変換された熱を効果的に処理することができる。また、クラッドモード光により生じる熱による光ファイバの温度上昇が効果的に抑制されることにより、光ファイバの信頼性が損なわれることが防止され、レーザ装置の信頼性を確保しつつ高出力化を実現することが可能となる。 In the laser apparatus 2101 having such a configuration, the above-described cladding mode light removing structure is used, for example, in the optical fiber amplifier 2102, a fusion splicing section 2140 for fusion splicing the first delivery fiber 2130 and the second delivery fiber 2150. Can be applied to As described above, by applying the cladding mode light removing structure to the fusion splicing portion 2140, the pumping light or the amplification optical fiber that is not absorbed by the amplification optical fiber 2112 and propagates through the cladding of the first delivery fiber 2130. The clad mode light such as the laser light leaked from the core of the 2112 is converted into heat, and the heat converted from the clad mode light can be effectively processed. In addition, by effectively suppressing the temperature rise of the optical fiber due to the heat generated by the cladding mode light, it is possible to prevent the reliability of the optical fiber from being impaired, and to increase the output while securing the reliability of the laser device. It can be realized.
　なお、本発明に係るクラッドモード光除去構造は、融着接続部２１４０に限られず、クラッドモード光を除去したい任意の箇所に設けてよいことは言うまでもない。例えば、光ファイバ増幅器２１０２の前方インラインコンバイナ２１２２Ａや後方インラインコンバイナ２１２２Ｂに適用してもよい。 It is needless to say that the clad mode light removing structure according to the present invention is not limited to the fusion splicing portion 2140, and may be provided at any position where the clad mode light is to be removed. For example, the present invention may be applied to the front inline combiner 2122A and the rear inline combiner 2122B of the optical fiber amplifier 2102.
　また、図１２に示す例では、ＨＲ－ＦＢＧ２１１４側とＯＣ－ＦＢＧ２１１６側の双方に励起光源２１２０Ａ，２１２０Ｂとコンバイナ２１２２Ａ，２１２２Ｂが設けられており、双方向励起型のファイバレーザとなっているが、ＨＲ－ＦＢＧ２１１４側とＯＣ－ＦＢＧ２１１６側のいずれか一方にのみ励起光源とコンバイナを設置することとしてもよい。また、光共振器２１１０内でレーザ発振させるための反射手段としてＦＢＧに代えてミラーを用いることもできる。 In the example shown in FIG. 12, the pump light sources 2120A and 2120B and the combiners 2122A and 2122B are provided on both the HR-FBG2114 side and the OC-FBG2116 side, which is a bidirectional pump type fiber laser. An excitation light source and a combiner may be provided only on one of the HR-FBG2114 side and the OC-FBG2116 side. Further, a mirror can be used instead of the FBG as a reflection unit for causing laser oscillation in the optical resonator 2110.
　図１３は、本発明に係るクラッドモード光除去構造を適用可能なレーザ装置の他の例を示す模式図である。図１３に示すレーザ装置３２０１は、ファイバレーザとして構成されており、レーザ光源としての光ファイバ増幅器３２０２とレーザ出射部３２６０とを備えている。光ファイバ増幅器３２０２は、信号光を発生させる信号光発生器３２１０と、励起光を発生させる複数の励起光源３２２０と、信号光発生器３２１０からの信号光と励起光源３２２０からの励起光とを結合して出力する光カプラ３２２２と、光カプラ３２２２の出力端３２２４に端部が接続された増幅用光ファイバ３２１２と、増幅用光ファイバ３２１２と融着接続部３２４０で融着接続されるデリバリファイバ３２５０を備えている。デリバリファイバ３２５０の下流側の端部には、増幅用光ファイバ３２１２からのレーザ発振光を例えば被処理物に向けて出射するレーザ出射部３２６０が設けられている。 FIG. 13 is a schematic view showing another example of a laser device to which the cladding mode light removing structure according to the present invention can be applied. A laser device 3201 shown in FIG. 13 is configured as a fiber laser, and includes an optical fiber amplifier 3202 as a laser light source and a laser emitting unit 3260. The optical fiber amplifier 3202 combines a signal light generator 3210 for generating signal light, a plurality of pump light sources 3220 for generating pump light, and a signal light from the signal light generator 3210 and a pump light from the pump light source 3220. Optical coupler 3222 for outputting the optical fiber 3122, an amplification optical fiber 3212 having an end connected to the output end 3224 of the optical coupler 3222, and a delivery fiber 3250 fusion-spliced with the amplification optical fiber 3212 at a fusion splicing section 3240. It has. At the downstream end of the delivery fiber 3250, a laser emitting unit 3260 that emits laser oscillation light from the amplification optical fiber 3212 toward, for example, an object to be processed is provided.
　図１４は、増幅用光ファイバ３２１２を模式的に示す断面図である。図１４に示すように、増幅用光ファイバ３２１２は、信号光発生器３２１０により生成された信号光を伝搬するコア３２１４と、コア３２１４の周囲に形成された内側クラッド３２１６と、内側クラッド３２１６の周囲に形成された外側クラッド３２１８とを有するダブルクラッドファイバによって構成される。コア３２１４は、例えばＹｂなどの希土類元素が添加されたＳｉＯ2からなり、信号光を伝搬する信号光導波路となっている。内側クラッド３２１６は、コア３２１４の屈折率よりも低い屈折率の材料（例えばＳｉＯ2）からなる。外側クラッド３２１８は、内側クラッド３２１６の屈折率よりも低い屈折率の樹脂（例えば低屈折率ポリマー）からなる。これにより、内側クラッド３２１６は励起光を伝搬する励起光導波路となる。 FIG. 14 is a cross-sectional view schematically showing the amplification optical fiber 3212. As shown in FIG. 14, the amplification optical fiber 3212 includes a core 3214 that propagates the signal light generated by the signal light generator 3210, an inner cladding 3216 formed around the core 3214, and a periphery of the inner cladding 3216. And a double clad fiber having an outer cladding 3218. The core 3214 is made of, for example, SiO 2 to which a rare earth element such as Yb is added, and serves as a signal light waveguide for transmitting signal light. The inner cladding 3216 is made of a material having a lower refractive index than the core 3214 (for example, SiO 2 ). The outer cladding 3218 is made of a resin having a lower refractive index than the inner cladding 3216 (for example, a low refractive index polymer). Thus, the inner cladding 3216 becomes an excitation light waveguide that propagates the excitation light.
　信号光発生器３２１０からの信号光は、増幅用光ファイバ３２１２のコア３２１４の内部を伝搬し、励起光源３２２０からの励起光は増幅用光ファイバ３２１２の内側クラッド３２１６及びコア３２１４の内部を伝搬する。励起光がコア３２１４を伝搬する際に、コア３２１４に添加された希土類元素イオンが励起光を吸収して励起され、誘導放出によってコア３２１４中を伝搬する信号光が増幅される。 The signal light from the signal light generator 3210 propagates inside the core 3214 of the amplification optical fiber 3212, and the pump light from the pump light source 3220 propagates inside the inner cladding 3216 and the core 3214 of the amplification optical fiber 3212. . When the excitation light propagates through the core 3214, the rare-earth element ions added to the core 3214 absorb and excite the excitation light, and the signal light propagating through the core 3214 is amplified by stimulated emission.
　このような構成のレーザ装置３２０１において、例えば増幅用光ファイバ３２１２とデリバリファイバ３２５０とを融着接続する融着接続部３２４０に上述したクラッドモード光除去構造を適用することができる。このように、光ファイバ増幅器３２０２の融着接続部３２４０にクラッドモード光除去構造を適用することで、増幅用光ファイバ３２１２にて吸収されなかった励起光や増幅用光ファイバ３２１２のコアから漏れ出たレーザ光などのクラッドモード光を効果的に熱に変換して除去することができ、この熱を効果的に処理することができる。 In the laser device 3201 having such a configuration, for example, the above-described cladding mode light removing structure can be applied to the fusion splicing portion 3240 that fusion-splices the amplification optical fiber 3212 and the delivery fiber 3250. As described above, by applying the clad mode light removing structure to the fusion splicing portion 3240 of the optical fiber amplifier 3202, the pump light not absorbed by the amplification optical fiber 3212 and the leakage from the core of the amplification optical fiber 3212 are prevented. The laser light or other clad mode light can be effectively converted to heat and removed, and this heat can be effectively processed.
　なお、本発明に係るクラッドモード光除去構造は、融着接続部３２４０に限られず、クラッドモード光を除去したい任意の箇所に設けることができることは言うまでもない。例えば、信号光発生器３２１０からの信号光と励起光源３２２０からの励起光とを結合して出力する光カプラ３２２２に適用してもよい。 It is needless to say that the clad mode light removing structure according to the present invention is not limited to the fusion splicing part 3240, and can be provided at an arbitrary position where the clad mode light is to be removed. For example, the present invention may be applied to an optical coupler 3222 that combines and outputs the signal light from the signal light generator 3210 and the pump light from the pump light source 3220.
　また、上述の実施形態では本発明に係るクラッドモード光除去構造をファイバレーザに適用した例を説明したが、ファイバレーザに限られず、半導体レーザなど、レーザ光源を有するレーザ装置に本発明を適用できることは言うまでもない。 In the above-described embodiment, the example in which the cladding mode light removing structure according to the present invention is applied to a fiber laser has been described. However, the present invention is not limited to the fiber laser, and can be applied to a laser device having a laser light source such as a semiconductor laser. Needless to say.
　なお、本明細書において使用した用語「上」や「底」などの位置関係を示す用語は、図示した実施形態との関連において使用されているのであり、装置の相対的な位置関係によって変化するものである。 Note that terms indicating a positional relationship such as the terms “top” and “bottom” used in the present specification are used in relation to the illustrated embodiment, and vary depending on the relative positional relationship of the device. Things.
　これまで本発明の好ましい実施形態について説明したが、本発明は上述の実施形態に限定されず、その技術的思想の範囲内において種々異なる形態にて実施されてよいことは言うまでもない。 Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention may be implemented in various forms within the scope of the technical idea.
　以上述べたように、本発明の第１の態様によれば、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造が提供される。このクラッドモード光除去構造は、光ファイバのクラッド内を伝搬するクラッドモード光を除去するために用いられる。上記クラッドモード光除去構造は、上記光ファイバを保持するファイバ保持部と、上記光ファイバの長手方向に沿って所定の長さで上記クラッドの全周のうち少なくとも一部を被覆材から露出させたクラッド露出部と、上記ファイバ保持部上に上記光ファイバの長手方向に離間して配置される複数の高屈折率樹脂部を備える。上記複数の高屈折率樹脂部は、上記クラッドの屈折率以上の屈折率を有している。また、上記複数の高屈折率樹脂部のそれぞれは、上記クラッドの周方向に沿って上記クラッド露出部の外周に接触するように形成される。なお、本発明における「クラッド」は、光ファイバが複数のクラッドを有する場合には、最外層のクラッドを意味する。 As described above, according to the first aspect of the present invention, there is provided a cladding mode light removing structure capable of removing cladding mode light while suppressing local heat generation by cladding mode light at low cost. This cladding mode light removing structure is used to remove cladding mode light propagating in the cladding of the optical fiber. The cladding mode light removing structure, a fiber holding portion holding the optical fiber, and at least a part of the entire circumference of the cladding is exposed from the coating material at a predetermined length along the longitudinal direction of the optical fiber. The optical fiber includes a clad exposed portion and a plurality of high refractive index resin portions disposed on the fiber holding portion so as to be separated from each other in a longitudinal direction of the optical fiber. The plurality of high refractive index resin portions have a refractive index equal to or higher than the refractive index of the cladding. Further, each of the plurality of high refractive index resin portions is formed so as to contact the outer periphery of the clad exposed portion along the circumferential direction of the clad. The “cladding” in the present invention means the outermost cladding when the optical fiber has a plurality of claddings.
　このような構成では、光ファイバのクラッド露出部に接触する複数の高屈折率樹脂部の屈折率が光ファイバのクラッドの屈折率以上であるため、光ファイバのクラッドを伝搬するクラッドモード光は、クラッド露出部におけるクラッドと高屈折率樹脂部との界面で高屈折率樹脂部に入射し、高屈折率樹脂部又はファイバ保持部で吸収されて熱に変換される。このような高屈折率樹脂部が光ファイバの長手方向に離間して配置されているため、光ファイバのクラッドを伝搬するクラッドモード光をそれぞれの高屈折率樹脂部で段階的に熱に変換して除去することが可能となり、除去するクラッドモード光の量を適切に制御して局所的な発熱を抑制することができる。このような高屈折率樹脂部の形成はレーザ加工装置のような高価な設備を必要としないため、クラッドモード光による局所的な発熱を安価に抑制することが可能である。 In such a configuration, since the refractive indices of the plurality of high refractive index resin portions that are in contact with the exposed portion of the cladding of the optical fiber are equal to or higher than the refractive index of the cladding of the optical fiber, the cladding mode light propagating through the cladding of the optical fiber is: At the interface between the clad and the high-refractive-index resin part in the clad exposed part, the light enters the high-refractive-index resin part, is absorbed by the high-refractive-index resin part or the fiber holding part, and is converted into heat. Since such high-refractive-index resin portions are arranged apart from each other in the longitudinal direction of the optical fiber, the cladding mode light propagating through the cladding of the optical fiber is converted into heat in each high-refractive-index resin portion stepwise. It is possible to appropriately control the amount of the cladding mode light to be removed, thereby suppressing local heat generation. Since the formation of such a high refractive index resin portion does not require expensive equipment such as a laser processing device, local heat generation due to cladding mode light can be suppressed at low cost.
　上記クラッドモード光除去構造は、上記ファイバ保持部に接続され、上記ファイバ保持部から熱を放出する放熱部をさらに備えていてもよい。このような構成により、高屈折率樹脂部を介して熱に変換されたクラッドモード光をファイバ保持部から放熱部を通じて効率的に外部に放出することができる。 The cladding mode light removing structure may further include a heat radiating unit connected to the fiber holding unit and emitting heat from the fiber holding unit. With such a configuration, the clad mode light converted into heat via the high refractive index resin portion can be efficiently emitted to the outside from the fiber holding portion through the heat radiating portion.
　上記ファイバ保持部には、上記複数の高屈折率樹脂部が配置される複数の樹脂溝が形成されていてもよい。このような樹脂溝に高屈折率樹脂部を配置することにより、光ファイバからより離れた位置でクラッドモード光を熱に変換することができるので、クラッドモード光により生じる熱が光ファイバに与える影響を低減することができる。また、上述した放熱部をファイバ保持部に接続する場合には、放熱部により近い位置でクラッドモード光を熱に変換することができるので、クラッドモード光により生じた熱を効率的に外部に放出することが可能となる。 複数 A plurality of resin grooves in which the plurality of high refractive index resin portions are arranged may be formed in the fiber holding portion. By arranging a high-refractive-index resin portion in such a resin groove, the clad mode light can be converted to heat at a position farther from the optical fiber, so that the heat generated by the clad mode light affects the optical fiber. Can be reduced. In addition, when the above-described heat radiating section is connected to the fiber holding section, the clad mode light can be converted to heat at a position closer to the heat radiating section, so that the heat generated by the clad mode light can be efficiently radiated to the outside. It is possible to do.
　上記クラッド露出部は、上記クラッドの全周が上記被覆材から露出している部分を含んでいてもよい。この場合には、クラッドの全周が上記被覆材から露出している部分においては被覆材が存在しないため、処理できるクラッドモード光のパワーが被覆材によって制限を受けない。このため、より高パワーのクラッドモード光を処理することができる。 The exposed clad portion may include a portion where the entire periphery of the clad is exposed from the coating material. In this case, since there is no coating material in a portion where the entire circumference of the cladding is exposed from the coating material, the power of the clad mode light that can be processed is not limited by the coating material. Therefore, higher power clad mode light can be processed.
　上記クラッド露出部は、上記クラッドの全周のうち一部が上記被覆材から露出している部分を含んでいてもよい。このような構成とすることで、被覆材の全周の一部にクラッド露出部が覆われ、これにより補強されるため、クラッドモード光除去構造の機械的強度を向上させることができる。 ク ラ ッ ド The exposed clad portion may include a portion of the entire circumference of the clad that is partially exposed from the coating material. With such a configuration, the cladding exposed portion is covered on a part of the entire circumference of the coating material and is reinforced by the cladding, so that the mechanical strength of the cladding mode light removing structure can be improved.
　また、上記複数の高屈折率樹脂部の少なくとも１つが上記クラッド露出部の外周に接触する領域の周方向の範囲は、上記光ファイバの光軸を中心として２５度から１８０度の範囲であることが好ましい。 Further, a circumferential range of a region where at least one of the plurality of high refractive index resin portions contacts the outer periphery of the clad exposed portion is in a range of 25 degrees to 180 degrees around the optical axis of the optical fiber. Is preferred.
　本発明の第２の態様によれば、高出力化が可能なレーザ装置が提供される。このレーザ装置は、レーザ光源と、上記レーザ光源に接続された光ファイバと、上述したクラッドモード光除去構造とを備える。上記クラッドモード光除去構造は、上記レーザ光源に接続された上記光ファイバのクラッド内を伝搬するクラッドモード光を除去するように構成されている。 According to the second aspect of the present invention, there is provided a laser device capable of increasing the output. This laser device includes a laser light source, an optical fiber connected to the laser light source, and the above-described cladding mode light removing structure. The cladding mode light removing structure is configured to remove cladding mode light propagating in the cladding of the optical fiber connected to the laser light source.
　このような構成によれば、上述したクラッドモード光除去構造により、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるため、レーザ装置の高出力化を実現することが可能となる。 According to such a configuration, the above-described clad mode light removing structure can remove the clad mode light while suppressing local heat generation due to the clad mode light at low cost, thereby realizing a high output laser device. It is possible to do.
　本発明の第３の態様によれば、クラッドモード光による局所的な発熱を安価に抑制しつつクラッドモード光を除去することができるクラッドモード光除去構造を容易に製造することができる方法が提供される。この方法によれば、光ファイバのクラッド内を伝搬するクラッドモード光を除去するクラッドモード光除去構造が製造される。この方法では、光ファイバの長手方向に沿って所定の長さで被覆材を除去して、上記光ファイバのクラッドの全周のうち少なくとも一部を上記被覆材から露出させたクラッド露出部を形成し、上記クラッドの屈折率以上の屈折率を有する複数の高屈折率樹脂部をファイバ保持部上に長手方向に離間させて形成し、上記光ファイバの上記クラッド露出部を上記ファイバ保持部上の上記複数の高屈折率樹脂部に接触させた状態で、上記光ファイバを上記ファイバ保持部に固定する。 According to the third aspect of the present invention, there is provided a method capable of easily manufacturing a cladding mode light removing structure capable of removing cladding mode light while suppressing local heat generation by cladding mode light at low cost. Is done. According to this method, a cladding mode light removing structure for removing cladding mode light propagating in the cladding of the optical fiber is manufactured. In this method, the coating material is removed at a predetermined length along the longitudinal direction of the optical fiber to form a clad exposed portion in which at least a part of the entire circumference of the cladding of the optical fiber is exposed from the coating material. A plurality of high-refractive-index resin portions having a refractive index equal to or higher than the refractive index of the clad are formed on the fiber holding portion so as to be spaced apart in the longitudinal direction, and the clad exposed portion of the optical fiber is formed on the fiber holding portion. The optical fiber is fixed to the fiber holding portion while being in contact with the plurality of high refractive index resin portions.
　それぞれの高屈折率樹脂部で除去されるクラッドモード光の量は、それぞれの高屈折率樹脂部とクラッド露出部との間の接触面積を調整することで制御することができるが、これらの高屈折率樹脂部の形成は光ファイバの被覆材の除去よりも容易に制御することができるので、上述した方法によれば、それぞれの高屈折率樹脂部で除去されるクラッドモード光の量の制御が容易になる。したがって、クラッドモード光による局所的な発熱を安価に抑制しつつ、クラッドモード光を除去することができるクラッドモード光除去構造を容易に製造することができる。 The amount of the cladding mode light removed in each high refractive index resin portion can be controlled by adjusting the contact area between each high refractive index resin portion and the clad exposed portion. Since the formation of the refractive index resin portion can be controlled more easily than the removal of the coating material of the optical fiber, according to the above-described method, the control of the amount of the cladding mode light removed by each of the high refractive index resin portions is performed. Becomes easier. Therefore, it is possible to easily manufacture a clad mode light removing structure capable of removing clad mode light while suppressing local heat generation due to clad mode light at low cost.
　さらに、上記ファイバ保持部から熱を放出する放熱部を上記ファイバ保持部に接続してもよい。このような放熱部により、高屈折率樹脂部を介して熱に変換されたクラッドモード光をファイバ保持部から効率的に放熱外部に放出することができる。 放熱 Furthermore, a heat radiating unit that emits heat from the fiber holding unit may be connected to the fiber holding unit. With such a heat radiating portion, the clad mode light converted into heat via the high refractive index resin portion can be efficiently emitted from the fiber holding portion to the outside of the heat radiating portion.
　また、上記複数の高屈折率樹脂部を形成する際に、上記ファイバ保持部に形成された複数の樹脂溝に上記複数の高屈折率樹脂部を配置してもよい。このような樹脂溝に高屈折率樹脂部を配置することで高屈折率樹脂部を所定の位置に正確に配置することができるので、高屈折率樹脂部とクラッド露出部との間の接触面積のばらつきを抑制することができる。したがって、それぞれの高屈折率樹脂部で除去されるクラッドモード光の量をより正確に制御することができる。 When forming the plurality of high-refractive-index resin sections, the plurality of high-refractive-index resin sections may be arranged in a plurality of resin grooves formed in the fiber holding section. By arranging the high-refractive-index resin portion in such a resin groove, the high-refractive-index resin portion can be accurately arranged at a predetermined position. Can be suppressed. Therefore, it is possible to more accurately control the amount of the cladding mode light removed by each high refractive index resin portion.
　本発明によれば、光ファイバのクラッドを伝搬するクラッドモード光による局所的な発熱を安価に抑制しつつ、クラッドモード光を除去することができる。 According to the present invention, it is possible to remove the cladding mode light while suppressing the local heat generation due to the cladding mode light propagating through the cladding of the optical fiber at low cost.
　本出願は、２０１８年８月２９日に提出された日本国特許出願特願２０１８－１５９８７４号に基づくものであり、当該出願の優先権を主張するものである。当該出願の開示は参照によりその全体が本明細書に組み込まれる。 This application is based on Japanese Patent Application No. 2018-159874 filed on Aug. 29, 2018, and claims the priority of the application. The disclosure of that application is incorporated herein by reference in its entirety.
　本発明は、ファイバレーザなどのレーザ装置における光ファイバのクラッドを伝搬するクラッドモード光を除去するクラッドモード光除去構造に好適に用いられる。 The present invention is suitably used for a cladding mode light removing structure for removing cladding mode light propagating through the cladding of an optical fiber in a laser device such as a fiber laser.
　　　１　　　クラッドモード光除去構造
　　１０　　　光ファイバ
　　１１　　　コア
　　１２　　　被覆材
　　１４　　　クラッド
　　１６　　　クラッド露出部
　　２０　　　ファイバ保持部
　　２２　　　ファイバ溝
　　２２Ａ　　底面
　　２４　　　固定樹脂
　　３０　　　蓋部材
　　４０　　　ヒートシンク（放熱部）
　　５０　　　高屈折率樹脂部
　１０１，２０１，３０１　　　クラッドモード光除去構造
　１３０　　　低屈折率樹脂
　２６０　　　樹脂溝
２１０１　　　レーザ装置
２１０２　　　光ファイバ増幅器
２１１０　　　光共振器
２１１２　　　増幅用光ファイバ
２１１４　　　ＨＲ－ＦＢＧ
２１１６　　　ＯＣ－ＦＢＧ
２１２０Ａ，２１２０Ｂ　　励起光源
２１２２Ａ，２１２２Ｂ　　インラインコンバイナ
２１３０　　　第１のデリバリファイバ
２１４０　　　融着接続部
２１５０　　　第２のデリバリファイバ
２１６０　　　レーザ出射部
３２０１　　　レーザ装置
３２０２　　　光ファイバ増幅器
３２１０　　　信号光発生器
３２１２　　　増幅用光ファイバ
３２１４　　　コア
３２１６　　　内側クラッド
３２１８　　　外側クラッド
３２２０　　　励起光源
３２２２　　　光カプラ
３２２４　　　出力端
３２４０　　　融着接続部
３２５０　　　デリバリファイバ
３２６０　　　レーザ出射部 DESCRIPTION OF SYMBOLS 1 Cladding mode light removal structure 10 Optical fiber 11 Core 12 Coating material 14 Cladding 16 Cladding exposed part 20 Fiber holding part 22 Fiber groove 22A Bottom surface 24 Fixed resin 30 Cover member 40 Heat sink (heat radiating part)
Reference Signs List 50 high refractive index resin portion 101, 201, 301 cladding mode light removing structure 130 low refractive index resin 260 resin groove 2101 laser device 2102 optical fiber amplifier 2110 optical resonator 2112 amplifying optical fiber 2114 HR-FBG
2116 OC-FBG
2120A, 2120B Excitation light sources 2122A, 2122B In-line combiner 2130 First delivery fiber 2140 Fusion splicing unit 2150 Second delivery fiber 2160 Laser emission unit 3201 Laser device 3202 Optical fiber amplifier 3210 Signal light generator 3212 Amplification optical fiber 3214 Core 3216 inner cladding 3218 outer cladding 3220 excitation light source 3222 optical coupler 3224 output end 3240 fusion splicing part 3250 delivery fiber 3260 laser emitting part

Claims (10)

  1. 　光ファイバのクラッド内を伝搬するクラッドモード光を除去するクラッドモード光除去構造であって、
    　前記光ファイバを保持するファイバ保持部と、
    　前記光ファイバの長手方向に沿って所定の長さで前記クラッドの全周のうち少なくとも一部を被覆材から露出させたクラッド露出部と、
    　前記ファイバ保持部上に前記光ファイバの長手方向に離間して配置される複数の高屈折率樹脂部であって、前記クラッドの屈折率以上の屈折率を有する複数の高屈折率樹脂部と
    を備え、
    　前記複数の高屈折率樹脂部のそれぞれは、前記クラッドの周方向に沿って前記クラッド露出部の外周に接触するように形成される、
    クラッドモード光除去構造。     A cladding mode light removing structure for removing cladding mode light propagating in the cladding of the optical fiber,
    A fiber holding unit for holding the optical fiber,
    A clad exposed portion where at least a part of the entire circumference of the clad is exposed from the coating material at a predetermined length along the longitudinal direction of the optical fiber,
    A plurality of high-refractive-index resin portions disposed on the fiber holding portion so as to be separated from each other in the longitudinal direction of the optical fiber, and a plurality of high-refractive-index resin portions having a refractive index equal to or higher than the refractive index of the cladding. Prepared,
    Each of the plurality of high refractive index resin portions is formed so as to contact the outer periphery of the clad exposed portion along the circumferential direction of the clad,
    Cladding mode light removal structure.
  2. 　前記ファイバ保持部に接続され、前記ファイバ保持部から熱を放出する放熱部をさらに備える、請求項１に記載のクラッドモード光除去構造。 The cladding mode light removing structure according to claim 1, further comprising: a heat radiating unit connected to the fiber holding unit and emitting heat from the fiber holding unit.
  3. 　前記ファイバ保持部には、前記複数の高屈折率樹脂部が配置される複数の樹脂溝が形成される、請求項１又は２に記載のクラッドモード光除去構造。 3. The clad mode light elimination structure according to claim 1, wherein a plurality of resin grooves in which the plurality of high refractive index resin portions are arranged are formed in the fiber holding portion. 4.
  4. 　前記クラッド露出部は、前記クラッドの全周が前記被覆材から露出している部分を含む、請求項１から３のいずれか一項に記載のクラッドモード光除去構造。 4. The clad mode light removing structure according to claim 1, wherein the clad exposed portion includes a portion where the entire circumference of the clad is exposed from the coating material. 5.
  5. 　前記クラッド露出部は、前記クラッドの全周のうち一部が前記被覆材から露出している部分を含む、請求項１から３のいずれか一項に記載のクラッドモード光除去構造。 4. The clad mode light removing structure according to claim 1, wherein the clad exposed portion includes a part of the entire circumference of the clad that is partially exposed from the coating material. 5.
  6. 　前記複数の高屈折率樹脂部の少なくとも１つが前記クラッド露出部の外周に接触する領域の周方向の範囲は、前記光ファイバの光軸を中心として２５度から１８０度の範囲である、請求項１から５のいずれか一項に記載のクラッドモード光除去構造。 The circumferential range of a region where at least one of the plurality of high refractive index resin portions contacts the outer periphery of the clad exposed portion is in a range of 25 degrees to 180 degrees around the optical axis of the optical fiber. 6. The cladding mode light removing structure according to any one of 1 to 5.
  7. 　レーザ光源と、
    　前記レーザ光源に接続された光ファイバと、
    　請求項１から６のいずれか一項に記載のクラッドモード光除去構造と
    を備え、
    　前記クラッドモード光除去構造は、前記レーザ光源に接続された前記光ファイバのクラッド内を伝搬するクラッドモード光を除去するように構成される、
    レーザ装置。     A laser light source,
    An optical fiber connected to the laser light source,
    A cladding mode light removing structure according to any one of claims 1 to 6,
    The cladding mode light removing structure is configured to remove cladding mode light propagating in the cladding of the optical fiber connected to the laser light source,
    Laser device.
  8. 　光ファイバのクラッド内を伝搬するクラッドモード光を除去するクラッドモード光除去構造を製造する方法であって、
    　光ファイバの長手方向に沿って所定の長さで被覆材を除去して、前記光ファイバのクラッドの全周のうち少なくとも一部を前記被覆材から露出させたクラッド露出部を形成し、
    　前記クラッドの屈折率以上の屈折率を有する複数の高屈折率樹脂部をファイバ保持部上に長手方向に離間させて形成し、
    　前記光ファイバの前記クラッド露出部を前記ファイバ保持部上の前記複数の高屈折率樹脂部に接触させた状態で、前記光ファイバを前記ファイバ保持部に固定する、
    クラッドモード光除去構造の製造方法。     A method for manufacturing a cladding mode light removal structure for removing cladding mode light propagating in the cladding of an optical fiber,
    Removing the coating material at a predetermined length along the longitudinal direction of the optical fiber, forming a clad exposed portion at least a portion of the entire circumference of the cladding of the optical fiber is exposed from the coating material,
    A plurality of high-refractive-index resin portions having a refractive index equal to or greater than the refractive index of the cladding are formed on the fiber holding portion so as to be spaced apart in the longitudinal direction,
    In a state where the clad exposed portion of the optical fiber is in contact with the plurality of high refractive index resin portions on the fiber holding portion, the optical fiber is fixed to the fiber holding portion,
    A method for manufacturing a cladding mode light removing structure.
  9. 　さらに、前記ファイバ保持部から熱を放出する放熱部を前記ファイバ保持部に接続する、請求項８に記載のクラッドモード光除去構造の製造方法。 The method for manufacturing a cladding mode light removing structure according to claim 8, further comprising connecting a heat radiating unit that emits heat from the fiber holding unit to the fiber holding unit.
  10. 　前記複数の高屈折率樹脂部を形成する際に、前記ファイバ保持部に形成された複数の樹脂溝に前記複数の高屈折率樹脂部を配置する、請求項８又は９に記載のクラッドモード光除去構造の製造方法。 The clad mode light according to claim 8, wherein, when forming the plurality of high-refractive-index resin portions, the plurality of high-refractive-index resin portions are arranged in a plurality of resin grooves formed in the fiber holding portion. Manufacturing method of the removal structure.
PCT/JP2019/033918 2018-08-29 2019-08-29 Cladding mode light removal structure, laser device, and method for manufacturing cladding mode light removal structure WO2020045569A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220302666A1 (en) * 2019-12-17 2022-09-22 Fujikura Ltd. Beam quality control device and laser device using same
JP7623202B2 (en) 2021-04-12 2025-01-28 古河電気工業株式会社 Light guide device, optical fiber assembly, and optical device

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002131550A (en) * 2000-10-25 2002-05-09 Mitsubishi Cable Ind Ltd Optical loss filter
JP2010181574A (en) * 2009-02-04 2010-08-19 Olympus Corp Method and apparatus for light filtering of double clad fiber
US20130016740A1 (en) * 2011-07-11 2013-01-17 Matthieu Saracco Fiber cladding light stripper
US20140363125A1 (en) * 2013-06-06 2014-12-11 Prima Electro North America, LLC Cladding mode stripper
JP2015145959A (en) * 2014-02-03 2015-08-13 株式会社フジクラ Excessive light removal structure and fiber laser
JP2016031523A (en) * 2014-07-30 2016-03-07 株式会社フジクラ Optical device, and method for producing optical device
JP2016161867A (en) * 2015-03-04 2016-09-05 株式会社フジクラ Optical power monitor device and fiber laser device
JP2016529548A (en) * 2013-08-07 2016-09-23 コラクティブ・ハイ−テック・インコーポレイテッドＣｏｒａｃｔｉｖｅ Ｈｉｇｈ−Ｔｅｃｈ Ｉｎｃ． Spatial modulation cladding mode stripper and optical fiber having the same

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002131550A (en) * 2000-10-25 2002-05-09 Mitsubishi Cable Ind Ltd Optical loss filter
JP2010181574A (en) * 2009-02-04 2010-08-19 Olympus Corp Method and apparatus for light filtering of double clad fiber
US20130016740A1 (en) * 2011-07-11 2013-01-17 Matthieu Saracco Fiber cladding light stripper
US20140363125A1 (en) * 2013-06-06 2014-12-11 Prima Electro North America, LLC Cladding mode stripper
JP2016529548A (en) * 2013-08-07 2016-09-23 コラクティブ・ハイ−テック・インコーポレイテッドＣｏｒａｃｔｉｖｅ Ｈｉｇｈ−Ｔｅｃｈ Ｉｎｃ． Spatial modulation cladding mode stripper and optical fiber having the same
JP2015145959A (en) * 2014-02-03 2015-08-13 株式会社フジクラ Excessive light removal structure and fiber laser
JP2016031523A (en) * 2014-07-30 2016-03-07 株式会社フジクラ Optical device, and method for producing optical device
JP2016161867A (en) * 2015-03-04 2016-09-05 株式会社フジクラ Optical power monitor device and fiber laser device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220302666A1 (en) * 2019-12-17 2022-09-22 Fujikura Ltd. Beam quality control device and laser device using same
JP7623202B2 (en) 2021-04-12 2025-01-28 古河電気工業株式会社 Light guide device, optical fiber assembly, and optical device

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