JP2011124363A - Method and device for manufacturing double-clad fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for manufacturing a double-clad fiber generating no connection loss. <P>SOLUTION: Two base materials of a laser-beam waveguide base material 10 and an excitation-light waveguide base material 11 are scribed fixed length with an interval therebetween and the two base materials of the laser-beam waveguide base material 10 and the excitation-light waveguide base material 11 are brought into contact with each other. A contact part is heated additionally by the laser beams of a carbon-dioxide laser device 29 to be melted and unified, a fixed length of scribing is performed and then a fixed length of scribing is further performed with an interval between the two base materials of the laser-beam waveguide base material 10 and the excitation-light waveguide base material 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a double clad fiber and an apparatus for producing a double clad fiber.

  In recent years, with the advent of double-cladding fibers, fiber lasers have been increased in output and are being applied in the field of material processing. In order to increase the output, a non-circular cross-section technique using an inner cladding cross-sectional shape is used in order to guide excitation light with high optical output.

  A conventional double-clad fiber having a non-circular cross-section inner clad is manufactured by heating, melting, stretching, and drawing an optical fiber preform having the cross-section (see, for example, Patent Document 1).

  Further, in the double clad fiber manufactured in this way, an excitation optical fiber that guides excitation light is connected to the inner clad of the double clad fiber in order to constitute a fiber laser (see, for example, Patent Document 2).

  FIG. 7 shows a schematic diagram of the connecting portion between the conventional double clad fiber and the pumping light.

  As shown in the figure, a double clad fiber 100 is configured by arranging a core 101 including a laser medium at the center, an inner clad 102 having a non-circular cross section around the core 101, and a coating 103 around the inner clad 102. is doing.

  The inner clad 102 is optically connected to the pumping optical fiber 104 that transmits the pumping light by fusion, and the core 101 is optically connected to the laser optical fiber 105 that extracts the laser light by fusion.

  The operation of the double clad fiber configured as described above and the pumping optical fiber will be described.

  Excitation light for exciting the laser medium of the core 101 enters the inner clad 102 from the excitation optical fiber 104 through the fusion part, and enters the core 101 to excite the laser medium.

  Multiple excitation feedback is performed by this excitation and an optical resonator (not shown) provided in the laser optical fiber 105 so that the laser light is emitted from the end face of the laser optical fiber 105.

JP 2003-226540 A (first page, FIG. 1) US Pat. No. 5,488,506 (first page, FIG. 2)

  However, the conventional connection between the double-clad fiber and the pumping optical fiber is separate from the double-clad fiber and the pumping optical fiber, and is integrated by fusion. Had.

  An object of the present invention is to provide a double-clad fiber manufacturing method and a double-clad fiber manufacturing apparatus in which a double-clad fiber and a pumping optical fiber are integrated at the time of manufacturing and no connection loss occurs.

  In order to solve the above-described problems, a method of manufacturing a double clad fiber according to the present invention includes a laser medium that generates laser light, an optical fiber base material that is surrounded by an inner clad, and an excitation that excites the laser medium. When heating and drawing a base material of an optical fiber that guides light, after drawing a predetermined length with a gap between the two base materials, the two base materials are brought into contact with each other, Additional heating and fusion integration, drawing a predetermined length, and then drawing the predetermined length with an interval between the two base materials, and the double-clad fiber manufacturing apparatus of the present invention Includes a laser medium that generates a laser beam, a laser optical waveguide base material chuck that holds a base material of an optical fiber that is covered with an inner cladding, and light that guides excitation light that excites the laser medium. An excitation optical waveguide base material chuck for holding a fiber base material, a furnace for heating the two base materials, and a winding mechanism for winding a drawn double clad fiber, the laser optical waveguide base material chuck and the excitation A moving means for changing the interval between the optical waveguide base material chucks and a heating means for additionally heating a contact portion where the two base materials are contacted by the moving means are provided.

  With this method and configuration, the base material can be integrated and separated during drawing, and a double clad fiber in which the pumping optical fiber is integrated can be manufactured.

  In addition, another double-clad fiber manufacturing method of the present invention includes a laser medium that generates a laser beam, an optical fiber base material that is covered with an inner cladding, and excitation light that excites the laser medium. A predetermined position of the two base materials of the base material of the optical fiber to be waved is optically connected with the same material as the base material for guiding the excitation light, and the two base materials are drawn while being heated.

  By this method, the double clad fiber and the pumping optical fiber can be integrated.

  As described above, according to the present invention, a double-clad fiber in which a double-clad fiber and a pumping optical fiber are integrated can be manufactured. Thus, conventionally, it is necessary to separately fuse the double-clad fiber and the pumping optical fiber. In addition, it is possible to provide a double clad fiber having no fusion loss at the fusion part.

Schematic configuration diagram of a double-clad fiber manufacturing apparatus in Embodiment 1 of the present invention (A) FIG. 2 (c) is a cross-sectional view of the AA portion in the vicinity of the center in the longitudinal direction of the double clad fiber according to the first embodiment of the present invention, and (b) a double clad according to the first embodiment of the present invention. 2 (c) is a cross-sectional view in the direction of the arrow of BB in the vicinity of the fiber end face, (c) a schematic diagram of the excitation light introducing portion (with coating) of the double clad fiber of the present invention, and (d) the present invention. Schematic diagram of pump light introduction part (coating removal) of double clad fiber The conceptual diagram which shows operation | movement of the double clad fiber manufacturing apparatus in Embodiment 1 of this invention The conceptual diagram which shows operation | movement of the double clad fiber manufacturing apparatus in Embodiment 1 of this invention Schematic configuration diagram of a double-clad fiber manufacturing apparatus in Embodiment 2 of the present invention The conceptual diagram which shows operation | movement of the double clad fiber manufacturing apparatus in Embodiment 2 of this invention 7A is a cross-sectional view of the conventional double-clad fiber in FIG. 7B taken along the arrow AA, and FIG. 7B is a schematic diagram of a connection portion between the conventional double-clad fiber and pumping light.

  Embodiments for carrying out the present invention will be described with reference to the drawings.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to FIGS. In addition, the same number is attached | subjected to the same structure and the description is abbreviate | omitted.

  FIG. 1 is a schematic configuration diagram of a double-clad fiber manufacturing apparatus according to Embodiment 1 of the present invention, and FIG. 2 (a) is a view near the center in the longitudinal direction of the double-clad fiber according to Embodiment 1 of the present invention. c) A cross-sectional view of the AA portion in the arrow direction, FIG. 2B is a cross-sectional view of the double-clad fiber end surface in FIG. 2 (c) BB portion in the arrow direction in the first embodiment of the present invention. FIGS. 2 (c) and 2 (d) are schematic views of an excitation light introducing portion of the double clad fiber of the present invention. FIG. 2D is a view in which the coating of the excitation light introducing portion is removed from FIG. FIG. 3 is a conceptual diagram of the operation of the double clad fiber manufacturing apparatus according to the first embodiment, and is a conceptual diagram of an operation in which two base materials are integrated from (a) to (d). FIG. It is a conceptual diagram of operation | movement of the double clad fiber manufacturing apparatus in the form 1 of this, It is a conceptual diagram of operation | movement which the two base materials integrated from (a) to (c) isolate | separate.

  As shown in FIG. 2A, the double clad fiber 23 of the present embodiment includes a laser medium, a core 31 having a circular cross-sectional shape, and two circles that transmit excitation light from around the core 31. The inner cladding 33 has a cross-sectional shape in which a part of the inner cladding 33 is overlapped, and the coating 32 that confines the excitation light outside the inner cladding 33.

  As shown in FIGS. 2C and 2D, the inner clad 33 is branched into an excitation optical waveguide 34 that transmits excitation light and a laser optical waveguide 35 that transmits laser light (see FIG. 2 ( (b) having a cross section shown in FIG. 2) or joining (part having a cross section shown in FIG. 2A), both waveguides are covered with a coating 32.

  An apparatus for manufacturing such a double clad fiber will be described below.

  As shown in FIG. 1, the laser optical waveguide preform 10 is an optical fiber preform necessary for manufacturing the laser optical waveguide 35 including the core 31, and the laser optical waveguide preform that holds the laser optical waveguide preform 10. A laser optical waveguide base material moving mechanism 14 serving as a moving means for moving the laser optical waveguide base material 10 via the chuck 12 is attached.

  Similarly, the pumping optical waveguide base material 11 is an optical fiber base material necessary for manufacturing the pumping optical waveguide 34, and the pumping optical waveguide base material chuck 13 holding the pumping optical waveguide base material 11 is used as the pumping optical waveguide base material 11. It is attached to an excitation optical waveguide base material moving mechanism 15 which is a moving means for moving the base material 11.

  Both the laser optical waveguide base material moving mechanism 14 and the excitation optical waveguide base material moving mechanism 15 are connected to a moving mechanism control device 28 that controls them, and the moving mechanism control device 28 uses the manufacturing apparatus of the present embodiment. It is connected to a control device 27 to be controlled.

  A furnace 16 for melting the two base materials of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 includes a heater 17 serving as a heating source inside, and a carbon dioxide laser device in a part of the container. A window 18 of zinc selenide (ZnSe) that transmits 29 laser beams is provided, and a hole through which the laser beams pass is also provided in the heater 17. The window 18 is provided at a position where the laser beam of the carbon dioxide laser device can be guided to the vicinity of the position where the temperature inside the furnace 16 becomes maximum by the heater 17.

  At the outlet of the furnace 16 (lower part of the furnace 16), a fiber diameter and a wire diameter / wire position measuring device 19 for measuring the position are provided. The wire diameter / wire position measuring device 19 is connected to a control device 27 that controls the manufacturing device of the present embodiment.

  A coating cup 22 for applying the coating 32 is provided below the wire diameter / line position measuring device 19, and a UV light source 24 for curing the coating 32 is further provided below the coating cup 22.

  In addition, a capstan 25 that takes up the double-clad fiber manufactured by the manufacturing apparatus and a take-up mechanism 26 that takes up the double-clad fiber are provided. Further, the capstan 25 and the winding mechanism 26 are connected to a control device 27 that controls the manufacturing apparatus of the present embodiment.

  Also, a carbon dioxide laser device 29 is installed as a heating means for additionally heating so that the laser optical waveguide base material 10 inside the furnace 16 and the melted portion of the excitation optical waveguide base material 11 can be irradiated through the window 18. The carbon dioxide laser device 29 is connected to a control device 27 that controls the manufacturing device of the present embodiment.

  The operation of the double-clad fiber manufacturing apparatus configured as described above, that is, a drawing process as a manufacturing method will be described with reference to FIGS.

  First, the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are inserted into the furnace 16 by a base material insertion mechanism (not shown) at a predetermined interval, preferably 5 mm.

  When the inside of the furnace 16 reaches the melting temperature of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 by the heater 17, the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are reduced in diameter by their own weight while melting, Each is drawn to the bare laser optical waveguide 20 and the bare bare optical waveguide 21.

  The laser optical waveguide bare optical fiber 20 and the pumping optical waveguide bare optical fiber 21 are close to each other when passing through the coating cup 22, and the coating 32 is applied while being close to each other, and the coating 32 is cured by the UV light source 24. It becomes the double clad fiber 23 of the form 1, and becomes the end portion of the double clad fiber 23 formed by the excitation optical waveguide 34 and the laser optical waveguide 35 being close to each other (in the state of FIG. 2B).

  Thereafter, the double clad fiber 23 is taken up by a capstan 25 and taken up by a take-up mechanism 26.

  At this time, the take-up speed of the capstan 25 and the take-up speed of the take-up mechanism 26 are controlled by a signal from the wire diameter / wire position measuring device 19 via the control device 27, so that the laser optical waveguide bare optical fiber 20. , And control and monitor the diameter of the pumped optical waveguide bare optical fiber 21.

  Next, after winding the excitation optical waveguide 34 and the laser optical waveguide 35 to a desired length, the distance between the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 is reduced (state shown in FIG. 3A) and contacted. (State of FIG. 3B), the laser light of the carbon dioxide laser device 29 is applied to the tip contact portion of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11, and the laser optical waveguide base material 10 and the excitation optical waveguide base material. Irradiate until the material 11 is integrated (state of FIG. 3C).

  The inner clad bare optical fiber 30 is formed by the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 integrated by irradiation (state of FIG. 3D). At this time, the cross section of the inner clad bare optical fiber 30 becomes the shape of the inner clad 33 having a cross sectional shape in which a part of two circles are overlapped.

  Thereafter, the inner clad bare optical fiber 30 passes through the wire diameter / wire position measuring device 19 and the coating cup 22 and is coated with a coating 32 to become a double clad fiber 23, which becomes the center of the double clad fiber 23 (FIG. 2A). State). At this time, by controlling the take-up speed of the capstan 25 and the take-up speed of the take-up mechanism 26 via the control device 27 according to the signal from the wire diameter / wire position measuring device 19, the laser optical waveguide bare optical fiber 20. And the diameter of the pumped optical waveguide bare optical fiber 21 is controlled and monitored.

  And after winding up the length of the desired double clad fiber 23, the space | interval of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 is made into the front-end | tip contact part of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 Is expanded until they are separated (the state from FIG. 4A to FIG. 4C).

  By this separation, the laser optical waveguide preform 10 and the pump optical waveguide preform 11 become the laser optical waveguide bare optical fiber 20 and the pump optical waveguide bare optical fiber 21, respectively.

  Similarly, the laser optical waveguide bare optical fiber 20 and the pumping optical waveguide bare optical fiber 21 pass through the wire diameter / line position measuring device 19 and the coating cup 22 and are coated with a coating 32 to form a double clad fiber 23. 23 (state of FIG. 2B). At this time, by controlling the take-up speed of the capstan 25 and the take-up speed of the take-up mechanism 26 via the control device 27 according to the signal from the wire diameter / wire position measuring device 19, the laser optical waveguide bare optical fiber 20. The diameter of the bare optical fiber 21 of the excitation optical waveguide is controlled and monitored.

  In the present embodiment, the number of the base materials is two, such as the laser optical waveguide base material 10 and the excitation optical waveguide base material 11, but there may be a large number of base materials, and the base materials may be integrated and separated. However, either one may be performed.

  As described above, the laser optical waveguide preform 10 of the optical fiber in which the periphery of the core 31 including the laser medium that generates the laser light is covered with the laser optical waveguide 35 and the excitation light that excites the core 31 including the laser medium. When heating and drawing the excitation optical waveguide base material 11 of the optical fiber to be guided, the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are spaced apart from each other with a predetermined length. After drawing, the two base materials of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are brought into contact with each other, and the contact portion is additionally heated with the laser beam of the carbon dioxide gas laser device 29 to be melted and integrated to have a predetermined length. After that, the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are drawn with a predetermined length by separating the two base materials, and a laser medium for generating laser light is drawn. Including core 31 A laser optical waveguide preform chuck 12 for holding a laser optical waveguide preform 10 of an optical fiber whose periphery is covered with a laser optical waveguide 35, and an excitation optical waveguide preform of an optical fiber for guiding excitation light for exciting the laser medium. Excitation optical waveguide base material chuck 13 for holding 11, furnace 16 for heating two base materials of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11, and a winding mechanism for winding the drawn double clad fiber 26, a laser optical waveguide base material moving mechanism 14, an excitation optical waveguide base material moving mechanism 15, and a laser optical waveguide base material moving mechanism 15, which can change the distance between the laser optical waveguide base material chuck 12 and the excitation optical waveguide base material chuck 13. The contact portion where the two base materials of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are contacted by the material moving mechanism 14 and the excitation optical waveguide base material moving mechanism 15 is added. In is provided with a carbon dioxide gas laser apparatus 29 for heating.

  As described above, the distance between the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 is reduced and the vicinity of the tip is heated to be integrated, or the distance between the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 is increased. By separating, it is possible to manufacture a double-clad fiber in which a double-clad fiber and a pumping optical fiber are integrated, so that there is no need to separately fuse the double-clad fiber and the pumping optical fiber as in the past, Furthermore, it is possible to provide a double clad fiber having no fusion loss at the fusion part.

  In this embodiment, the carbon dioxide laser device is used as the heating means. However, a carbon dioxide gas laser device may be used, and other heating means may be used.

(Embodiment 2)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 2, FIG. 5, and FIG.

  In addition, the same number is attached | subjected to the structure same as Embodiment 1, and the description is abbreviate | omitted.

  FIG. 5 is a schematic configuration diagram of the double clad fiber manufacturing apparatus according to the second embodiment of the present invention, and FIG. 6 is a conceptual diagram of the operation of the double clad fiber manufacturing apparatus according to the second embodiment of the present invention (a). It is a conceptual diagram of the operation | movement which the base material isolate | separated from (c) to (c) unifies and isolate | separates again.

  The present embodiment is different from the first embodiment in that the shapes of the two base materials, the laser optical waveguide base material 10 and the excitation optical waveguide base material 11, and the absence of the window 18 through which laser light enters the furnace 42. The laser optical waveguide base material moving mechanism 14 and the excitation optical waveguide base material moving mechanism 15 have no moving means.

  As shown in FIG. 6, the trapezoidal base material 40 is the same as the excitation optical waveguide base material 11 in two places between the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 while maintaining a predetermined interval. It is a base material connected by material.

  The ladder-shaped base material chuck 41 is configured to hold the ladder-shaped base material 40 and insert it into the furnace 42 by a base material insertion mechanism (not shown).

  About the double clad fiber manufacturing apparatus comprised as mentioned above, the operation | movement, ie, the drawing process is demonstrated as a manufacturing method.

  First, the ladder-shaped base material 40 is inserted into the furnace 42 by a base material insertion mechanism (not shown).

  When the inside of the furnace 42 reaches the melting temperature of the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 by the heater 17, the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are reduced in diameter by their own weight while melting. Each is drawn to the bare optical fiber 20 of the laser optical waveguide and the bare optical fiber 21 of the excitation optical waveguide (state shown in FIG. 6A).

  The laser optical waveguide bare optical fiber 20 and the pumping optical waveguide bare optical fiber 21 are close to each other when passing through the coating cup 22, and the coating 32 is applied while being close to each other, and the coating 32 is cured by the UV light source 24. The double-clad fiber 23 of the first embodiment is formed, and the end portion of the double-clad fiber 23 formed by the excitation optical waveguide 34 and the laser optical waveguide 35 being close to each other (state shown in FIG. 2B).

  Thereafter, the double clad fiber 23 is taken up by a capstan 25 and taken up by a take-up mechanism 26.

  At this time, the take-up speed of the capstan 25 and the take-up speed of the take-up mechanism 26 are controlled by a signal from the wire diameter / wire position measuring device 19 via the control device 27, so that the laser optical waveguide bare optical fiber 20. And the diameter of the pumped optical waveguide bare optical fiber 21 is controlled and monitored.

  When reaching a portion where the predetermined laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are connected, the ladder-shaped base material 40 is integrated with the laser optical waveguide base material 10 and the excitation optical waveguide base material 11. Then, it is melted and reduced in diameter to become the inner clad bare optical fiber 30 (the state shown in FIG. 6B).

  At this time, the cross section of the inner clad bare optical fiber 30 becomes the shape of the inner clad 33 having a cross sectional shape in which a part of two circles are overlapped. Thereafter, the inner clad bare optical fiber 30 passes through the wire diameter / wire position measuring device 19 and the coating cup 22 and is coated with a coating 32 to become a double clad fiber 23, which becomes the center of the double clad fiber 23 (FIG. 2A). State).

  At this time, by controlling the take-up speed of the capstan 25 and the take-up speed of the take-up mechanism 26 via the control device 27 according to the signal from the wire diameter / wire position measuring device 19, the laser optical waveguide bare optical fiber 20. And the diameter of the pumped optical waveguide bare optical fiber 21 is controlled and monitored.

  Thereafter, when there is no longer a portion connecting the predetermined laser optical waveguide base material 10 and the excitation optical waveguide base material 11, the distance between the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 is widened. The base material 10 and the pumping optical waveguide base material 11 become the laser optical waveguide bare optical fiber 20 and the pumping optical waveguide bare optical fiber 21, respectively (state shown in FIG. 6C).

  Similarly, the laser optical waveguide bare optical fiber 20 and the pumping optical waveguide bare optical fiber 21 pass through the wire diameter / line position measuring device 19 and the coating cup 22 and are coated with a coating 32 to form a double clad fiber 23. 23 (state of FIG. 2B).

  At this time, by controlling the take-up speed of the capstan 25 and the take-up speed of the take-up mechanism 26 via the control device 27 according to the signal from the wire diameter / wire position measuring device 19, the laser optical waveguide bare optical fiber 20. And the diameter of the pumped optical waveguide bare optical fiber 21 is controlled and monitored.

  In this embodiment, there are two portions where the laser optical waveguide base material 10 and the excitation optical waveguide base material 11 are connected and the positions thereof are not questioned, but they may be changed according to desired characteristics.

  In the present embodiment, the outer diameter and core diameter of the laser optical waveguide base material 10 and the outer diameter of the excitation optical waveguide base material 11 are unquestioned with respect to the length direction. If the outer diameter and core diameter of the waveguide preform 10 and the outer diameter of the excitation optical waveguide preform 11 are reduced, a double-clad fiber with small variations in outer diameter and core diameter can be manufactured.

  As described above, the laser optical waveguide preform 10 of the optical fiber in which the periphery of the core 31 including the laser medium that generates the laser light is covered with the laser optical waveguide 35 and the excitation light that excites the core 31 including the laser medium. A predetermined position of the two base materials of the pumping optical waveguide base material 11 of the optical fiber to be guided is optically connected by the same material as the base material for guiding the pumping light, and the base material is drawn while being heated. Thus, a double clad fiber in which the double clad fiber and the pumping optical fiber are integrated can be manufactured. Therefore, there is no need to separately fuse the double clad fiber and the pumping optical fiber as in the prior art. It is possible to provide a double clad fiber having no fusion loss at the bonded portion.

  INDUSTRIAL APPLICABILITY According to the present invention, a double clad fiber and a pumping optical fiber are integrated at the time of production, and the double clad fiber production method and a double clad fiber production apparatus are produced that do not cause connection loss.

DESCRIPTION OF SYMBOLS 10 Laser optical waveguide base material 11 Excitation optical waveguide base material 12 Laser optical waveguide base material chuck 13 Excitation optical waveguide base material chuck 14 Laser optical waveguide base material moving mechanism 15 Excitation optical waveguide base material moving mechanism 16 Furnace 17 Heater 26 Winding mechanism 29 CO2 laser device 31 Core 32 Coating 33 Inner clad 34 Excitation optical waveguide 35 Laser optical waveguide 40 Ladder base material 41 Ladder base material chuck 42 Furnace

Claims (5)

  When heating and drawing an optical fiber base material including a laser medium that generates laser light and covered with an inner cladding, and an optical fiber base material that guides pumping light for exciting the laser medium After drawing a predetermined length with a gap between the two base materials, the two base materials are brought into contact with each other, the contact portion is additionally heated and melted and integrated, and the predetermined length is drawn. A method for producing a double-clad fiber, wherein a predetermined length is drawn with an interval between the two base materials.   The method for producing a double clad fiber according to claim 1, wherein the contact portion is additionally heated by a carbon dioxide gas laser device or a carbon dioxide gas laser device.   A laser optical waveguide base material chuck that holds a base material of an optical fiber that includes a laser medium that generates laser light and is surrounded by an inner cladding, and an optical fiber base that guides excitation light that excites the laser medium. An excitation optical waveguide base material chuck for holding the material; a furnace for heating the two base materials; and a winding mechanism for winding the drawn double clad fiber; and the laser optical waveguide base material chuck and the excitation optical waveguide base An apparatus for producing a double-clad fiber, comprising: a moving means for changing the interval between the material chucks; and a heating means for additionally heating a contact portion where the two base materials are contacted by the moving means.   The apparatus for producing a double clad fiber according to claim 3, wherein a carbon dioxide laser device or a carbon dioxide gas laser device is used as a heating means for additionally heating the contact portion.   Predetermined positions of two base materials: an optical fiber base material that includes a laser medium that generates laser light and whose periphery is covered with an inner cladding, and an optical fiber base material that guides excitation light that excites the laser medium. Is optically connected with the same material as the base material for guiding the excitation light, and the two base materials are drawn while being heated.

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