JP5128913B2 - Manufacturing method of optical combiner - Google Patents

Description

  The present invention is composed of one signal optical fiber and a plurality of pumping optical fibers, and at the tip portion thereof, the plurality of pumping optical fibers surround the signal optical fiber as a center. The present invention relates to a method of manufacturing an integrated optical combiner.

  In an optical apparatus such as a fiber laser or an optical amplifier, a double clad fiber is widely used as an optical amplification element.

  The double-clad fiber is provided in the center of the fiber doped with a rare earth element as an optical amplification component, a lower refractive index first clad provided around the core, and the first clad. And a second clad having a lower refractive index. In such a double-clad fiber, the excitation light incident on the first cladding propagates through a region surrounded by the second cladding while repeating reflection at the interface between the first cladding and the second cladding, and the excitation light. When passing through the core, the rare earth element doped in the core is turned into an inverted distribution state excited by the outermost electrons, and the signal light propagating through the core is amplified by the stimulated emission.

  In such a double clad fiber, a method using an optical combiner is known as a method of making signal light enter the core and pump light incident on the first clad.

The optical combiner has, for example, a close-packed structure of a single single-mode optical fiber at the center and six multi-mode optical fibers surrounding the single-mode optical fiber, and has a structure in which they are fused and integrated at the tip portion (Patent Document) 1). When connected to the double clad fiber, the portion that was the core of the single mode optical fiber is connected corresponding to the core of the double clad fiber, and the portion that was the core of the multimode optical fiber is the first clad of the double clad fiber. Connected in response to.
JP 2007-163650 A

  It is an object of the present invention to provide a method capable of easily manufacturing an optical combiner with a high yield.

The present invention is composed of one signal optical fiber and a plurality of pumping optical fibers, and the plurality of pumping lights are surrounded by the signal optical fiber at the tip portion of the signal optical fiber. An optical combiner manufacturing method in which fibers are arranged and integrated,
A first step of inserting a capillary into the pipe material and inserting a signal optical fiber into the capillary from one end thereof;
The signal optical fiber is inserted and extended from one end side of the pipe member and is inserted into and held by the capillary inserted into the pipe member, and a plurality of excitations are provided to the pipe member from one end side thereof. A second step of inserting an optical fiber for use;
It is provided with.

  According to the present invention, by inserting the signal optical fiber into the capillary inserted into the pipe material, the signal optical fiber is reliably positioned at the center, so the signal optical fiber and the excitation optical fiber are inserted into the pipe material. In this case, the signal optical fiber is not positioned off the center, and therefore, the optical combiner can be easily manufactured with high yield.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows an optical combiner 10 according to the first embodiment. The optical combiner 10 is used by being connected to, for example, an optical amplifier of a laser marker or a double clad fiber of a welding fiber laser.

  The optical combiner 10 includes a pipe material 11, one signal optical fiber core wire 12, and a plurality of pumping optical fiber core wires 13. Each of the signal optical fiber core 12 and the plurality of excitation optical fiber cores 13 has the coating layers 14 and 15 peeled off from the tip of the core wire by a predetermined length, and the signal optical fiber 16 or the excitation light. As shown in FIG. 2, the optical combiner 10 positions the single signal optical fiber 16 and the plurality of pumping optical fibers 17 at the center of the signal optical fiber 16. They are bundled so as to be inserted and inserted into the pipe material 11, and at the tip portion thereof, they are formed into a melted portion 18 that is fused and reduced in diameter. FIG. 2 shows a form in which one signal optical fiber 16 and six pumping optical fibers 17 each having the same fiber diameter are provided in a hexagonal close-packed form.

  The pipe material 11 is made of, for example, quartz glass. For example, the pipe material 11 has a total length of 3 to 10 mm (excluding the melted portion 18) and an inner diameter of 380 to 400 μm.

  One signal optical fiber core 12 has a configuration in which a signal optical fiber 16 is covered with a coating layer 14. For example, the signal optical fiber core 12 is formed to have a total length of 1 to 10 m (including the melted portion 18) and a core diameter of 240 to 260 μm.

  The signal optical fiber 16 is made of, for example, quartz glass, and includes a high refractive index core 16a at the center of the fiber and a low refractive index clad 16b covering the periphery thereof. The signal optical fiber 16 may be one in which the core 16a is formed of quartz having a high refractive index doped with germanium or the like and the cladding 16b is formed of pure quartz, or the core 16a is formed of pure quartz. In addition, the cladding 16b may be formed of quartz having a low refractive index doped with fluorine or the like. The signal optical fiber 16 is generally composed of a single mode fiber. For example, the signal optical fiber 16 has a fiber length of 0.5 to 5 mm, a fiber diameter of 123 to 127 μm, and a core diameter of 10 to 60 μm, which are exposed when the coating layer 14 is peeled off.

  The covering layer 14 is made of, for example, an ultraviolet curable resin, a silicon resin, a nylon resin, or the like, and may be composed of a single layer or may be composed of a plurality of layers. The coating layer 14 has a layer thickness of, for example, 55 to 65 μm.

  Each of the plurality of pumping optical fiber cores 13 has a configuration in which the pumping optical fiber 17 is covered with a coating layer 15. The excitation optical fiber core wire 13 is formed, for example, so that the total length of the core wire is 1 to 10 m (including the melted portion 18) and the core wire diameter is 240 to 260 μm. The number of optical fiber core wires 13 for excitation is, for example, 3 to 10 (6 in FIGS. 1 to 4).

  Each excitation optical fiber 17 is made of, for example, quartz glass, and has a high-refractive index core 17a at the center of the fiber and a low-refractive index cladding 17b covering the periphery thereof. Each pumping optical fiber 17 may be one in which a core 17a is formed of quartz having a high refractive index doped with germanium or the like and a cladding 17b is formed of pure quartz, or the core 17a is formed of pure quartz. The clad 17b may be formed of quartz formed and doped with fluorine or the like to lower the refractive index. Each pumping optical fiber 17 is generally composed of a multimode fiber. Each of the excitation optical fibers 17 has, for example, a fiber length of 0.5 to 5 mm, a fiber diameter of 123 to 127 μm, and a core diameter of 80 to 115 μm, which are exposed when the coating layer 15 is peeled off. .

  The plurality of pumping optical fibers 17 may be configured with a uniform fiber diameter, or may be configured differently. The plurality of pumping optical fibers 17 may have a uniform core diameter, or may be configured differently.

  When the fiber diameters of the plurality of pumping optical fibers 17 are configured uniformly, the fiber diameter may be the same as or different from the fiber diameter of the signal optical fiber 16. However, the former is preferable from the viewpoint of the filling property into the pipe material 11.

  The covering layer 15 is made of, for example, an ultraviolet curable resin, a silicon resin, a nylon resin, or the like, and may be constituted by a single layer or may be constituted by a plurality of layers. The coating layer 15 has a layer thickness of, for example, 55 to 65 μm.

  In the melting part 18, the pipe material 11, one signal optical fiber 16, and a plurality of pumping optical fibers 17 are integrated, and one signal optical fiber 16 and a plurality of pumping optical fibers 17 are integrated therein. The cores 16a and 17a of the optical fiber 17 extend in the length direction, and the core 16a of the signal optical fiber 16 is positioned at the center on the end face as shown in FIG. The core arrangement positioned so as to surround the core 17a is exposed.

  In this optical combiner 10, the signal optical fiber 16 is connected to the signal light source, each of the plurality of pumping optical fibers 17 is connected to the pumping light source, and the end surface of the melting portion 18 is connected to the core and the first light source. And a double clad fiber having a second clad and fused and connected by arc discharge or the like. At this time, the core 16a of the signal optical fiber 16 at the end face of the melted portion 18 is a double-clad fiber core, and each core 17a of the plurality of pumping optical fibers 17 is a first clad of the double-clad fiber. Connected.

  Then, the signal light from the signal light source is incident on the core of the double clad fiber via the signal optical fiber 16, and the pump light from the pump light source is incident on the first clad of the double clad fiber via the pump optical fiber 17. Then, the excitation light incident on the first clad propagates through the region surrounded by the second clad while repeating reflection at the interface between the first clad and the second clad, and passes through the core when passing through the core. The rare earth element doped in is made into an inversion distribution state excited by outermost electrons, and the signal light propagating through the core is amplified by the stimulated emission.

  Next, the manufacturing method of this optical combiner 10 is demonstrated based on Fig.4 (a)-(d).

<Preparation steps>
A pipe member 11, one signal optical fiber core wire 12, a plurality of excitation optical fiber core wires 13, and a capillary 20 in addition to them are prepared. The pipe material 11 has a length of, for example, 30 to 80 mm. Each of the signal optical fiber core 12 and the plurality of excitation optical fiber cores 13 has a core length of, for example, 1 to 10 m.

  The capillary 20 is made of, for example, quartz glass. For example, the capillary 20 is formed to have a total length of 40 to 90 mm, an outer diameter of 350 to 390 μm, and an inner diameter of 130 to 170 μm.

  For each of the signal optical fiber core 12 and the plurality of excitation optical fiber cores 13, the coating layers 14 and 15 are peeled off from the tip of one core wire by a predetermined length, or the signal optical fiber 16 or the excitation fiber The optical fiber 17 for use is exposed. At this time, the peeling length of the coating layers 14 and 15 is set to 20 to 40 mm, for example.

<Signal optical fiber insertion step (first step)>
As shown in FIGS. 4A and 4B, the capillary 20 is inserted into the pipe material 11, and the signal optical fiber 16 is inserted into the capillary 20 from one end side thereof.

  At this time, after inserting the capillary 20 into the pipe material 11, the signal optical fiber 16 may be inserted into the capillary 20 inserted into the pipe material 11, and the signal light is previously inserted into the capillary 20 from one end side thereof. After inserting the fiber 16, the capillary 20 in which the signal optical fiber 16 is inserted may be inserted from one end side of the pipe material 11. The insertion length of the signal optical fiber 16 into the capillary 20 is, for example, 10 to 20 mm.

  When the signal optical fiber 16 is inserted into the capillary 20 inserted into the pipe material 11, from the viewpoint of facilitating the insertion operation of the signal optical fiber 16 into the capillary 20, as shown in FIG. It is preferable to insert the capillary 20 into the material 11 in a penetrating state. As shown in FIG. 4B, the capillary 20 is inserted so that the end portion is positioned inside the pipe member 11, and the signal optical fiber 16 is inserted from one end side of the pipe member 11, Further, it may be inserted into the capillary 20.

<Pumping optical fiber insertion step (second step)>
The signal optical fiber 16 is inserted and extended from one end side of the pipe material 11 and is inserted and held in the capillary 20 inserted in the pipe material 11, and as shown in FIG. 11, a plurality of pumping optical fibers 17 are inserted from one end side thereof.

  At this time, the signal optical fiber 16 may be brought into the above state by moving the capillary 20 in which the signal optical fiber 16 is inserted to the other end side of the pipe material 11. At this time, the signal optical fiber 16 may be moved together with the capillary 20 so that the signal optical fiber 16 is guided and introduced into the pipe material 11, or the signal optical fiber 16 is fixed and only the capillary 20 is fixed. The signal optical fiber 16 may be pulled out from the sheath of the capillary 20 by moving.

  The pumping optical fiber 17 may be inserted into the pipe member 11 with the capillary 20 fixed, or may be performed along with the movement of the capillary 20 described above. Further, from the viewpoint that the length of insertion into the pipe material 11 can be made uniform, it is preferable that the end surfaces of the plurality of excitation optical fibers 17 are brought into contact with the end surfaces of the capillaries 20. The pumping optical fibers 17 may be inserted into the pipe material 11 one by one, or a plurality of optical fibers 17 may be put together.

  From the viewpoint of facilitating the insertion work of the signal optical fiber 16 and the pumping optical fiber 17 into the pipe material 11, the outer diameter when these are bundled in the closest form is slightly smaller than the inner diameter of the pipe material 11. It is preferable to have.

  From the viewpoint of preventing the excitation optical fiber 17 from being inserted into the capillary 20, the difference between the inner diameter of the capillary 20 and the outer diameter of the insertion body into the capillary 20 is the largest of the plurality of excitation optical fibers 17. It is preferably smaller than the outer diameter of the small-diameter excitation optical fiber 17. Here, the outer diameter of the insertion body into the capillary 20 is the outer diameter of the signal optical fiber 16. On the other hand, from the viewpoint of facilitating the insertion operation of the signal optical fiber 16 into the capillary 20, the inner diameter of the capillary 20 is preferably 1.03 to 1.3 times the outer diameter of the signal optical fiber 16. .

  Further, from the viewpoint of preventing the excitation optical fiber 17 from fitting into the gap between the pipe material 11 and the capillary 20, the difference between the inner diameter of the pipe material 11 and the outer diameter of the capillary 20 is a plurality of excitation optical fibers. 17 is preferably smaller than the outer diameter of the pumping optical fiber 17 having the smallest diameter. On the other hand, from the viewpoint of facilitating the insertion of the capillary 20 into the pipe material 11, the inner diameter of the pipe material 11 is preferably 1.03 to 1.3 times the outer diameter of the capillary 20.

<Melting and cutting step>
As shown in FIG. 4 (d), the capillary 20 is removed from the pipe material 11, and one signal optical fiber 16 and a plurality of pumping optical fibers 17 are inserted into the pipe material 11. Subsequently, the pipe The central portion of the material 11 is heated and melted from the side using an arc discharge, a flame or the like, and the gaps are integrated while collapsing. At this time, heating temperature shall be 1500-2000 degreeC, for example. Further, the length of the part to be fused and integrated is set to 1 to 3 mm, for example.

  And after cooling, the optical combiner 10 is manufactured by putting a notch in the side surface of the melt-integrated part and cutting at that part.

  When the signal optical fiber 16 and the excitation optical fiber 17 are inserted into the pipe material 11, if they are bundled as they are and inserted into the pipe material 11, it is very difficult to position the signal optical fiber 16 at the center. . In particular, when the signal optical fiber 16 and the pumping optical fiber 17 are very thin and have the same fiber diameter, the difficulty becomes significant. However, according to the manufacturing method of the optical combiner 10 as described above, by inserting the signal optical fiber 16 into the capillary 20 inserted into the pipe material 11, the signal optical fiber 16 is reliably placed at the center of the pipe material 11. Therefore, when the signal optical fiber 16 and the pumping optical fiber 17 are inserted into the pipe member 11, the signal optical fiber 16 is not positioned off the center, so that the yield is high and the optical combiner can be easily used. 10 can be manufactured.

(Embodiment 2)
Next, the optical combiner 10 according to the second embodiment will be described.

  The optical combiner 10 includes a pipe material 11, one signal optical fiber core wire 12, a plurality of excitation optical fiber wires 13, and a spacer pipe 19. Each of the signal optical fiber core 12 and the plurality of excitation optical fiber cores 13 has the coating layers 14 and 15 peeled off from the tip of the core wire by a predetermined length, and the signal optical fiber 16 or the excitation light. The fiber 17 is exposed, and the optical combiner 10 includes the signal optical fiber 16 and the plurality of pumping optical fibers 17 in the same manner as in the first embodiment. When the gap is formed between the signal optical fiber 16 and the pumping optical fiber 17, the signal optical fiber 16 and the pumping optical fiber 17 are connected to each other. By arranging the spacer pipe 19 in the gap, the signal optical fiber 16, the excitation optical fiber 17, and the spacer pipe 19 are configured to be in a close packed state. And in the front-end | tip part, they are formed in the fusion | melting part 18 which was melt-integrated and reduced in diameter.

  For example, the pipe material 11 has a total length of 3 to 10 mm (excluding the melting portion 18) and an inner diameter of 520 to 540 μm.

  The spacer pipe 19 is made of, for example, quartz glass. For example, the spacer pipe 19 has a total length of 3 to 10 mm, an outer diameter of 230 to 270 μm, and an inner diameter of 130 to 170 μm.

  The other optical fiber cores 12 for signals, optical fiber cores 13 for excitation, melting portions 18 and the like have the same configuration as in the first embodiment.

  In this optical combiner 10, the signal optical fiber 16 is connected to the signal light source, each of the plurality of pumping optical fibers 17 is connected to the pumping light source, and the end surface of the melting portion 18 is connected to the core and the first light source. And a double clad fiber having a second clad and fused and connected by arc discharge or the like. At this time, the core 16a of the signal optical fiber 16 at the end face of the melted portion 18 is a double-clad fiber core, and each core 17a of the plurality of pumping optical fibers 17 is a first clad of the double-clad fiber. Connected.

  Then, the signal light from the signal light source is incident on the core of the double clad fiber via the signal optical fiber 16, and the pump light from the pump light source is incident on the first clad of the double clad fiber via the pump optical fiber 17. Then, the excitation light incident on the first clad propagates through the region surrounded by the second clad while repeating reflection at the interface between the first clad and the second clad, and passes through the core when passing through the core. The rare earth element doped in is made into an inversion distribution state excited by outermost electrons, and the signal light propagating through the core is amplified by the stimulated emission.

  FIG. 5 is an explanatory diagram illustrating a method for manufacturing the optical combiner 10 according to the second embodiment.

<Preparation steps>
A pipe member 11, a single signal optical fiber core wire 12, a plurality of excitation optical fiber core wires 13, a spacer pipe 19, and a capillary 20 in addition to them are prepared. The pipe material 11 has a length of, for example, 30 to 80 mm. The spacer pipe 19 has a length of 40 to 90 mm, for example. Each of the signal optical fiber core 12 and the plurality of excitation optical fiber cores 13 has a core length of, for example, 1 to 10 m.

  The capillary 20 is made of, for example, quartz glass. For example, the capillaries 20 are formed with a total length of 40 to 90 mm, an outer diameter of 450 to 490 μm, and an inner diameter of 330 to 370 μm.

  For each of the signal optical fiber core 12 and the plurality of excitation optical fiber cores 13, the coating layers 14 and 15 are peeled off from the tip of one core wire by a predetermined length, or the signal optical fiber 16 or the excitation fiber The optical fiber 17 for use is exposed. At this time, the peeling length of the coating layers 14 and 15 is set to 20 to 40 mm, for example.

<Signal optical fiber insertion step (first step)>
As shown in FIG. 5, the capillary 20 is inserted into the pipe material 11, and the capillary 20 having the signal optical fiber 16 inserted through the spacer pipe 19 is inserted from one end side thereof.

  At this time, after inserting the capillary 20 into the pipe member 11, the spacer pipe 19 is inserted into the capillary 20 inserted into the pipe member 11, and the signal optical fiber 16 is inserted into the spacer pipe 19 inserted into the capillary 20. It may be inserted. Alternatively, the capillary 20 may be inserted into the pipe material 11, and the signal optical fiber 16 inserted into the spacer pipe 19 may be inserted into the capillary 20 inserted into the pipe material 11. Alternatively, the capillary 20 in which the signal optical fiber 16 is inserted through the spacer pipe 19 is inserted, and the capillary 20 into which the signal optical fiber 16 is inserted into the spacer pipe 19 is inserted into the pipe member 11. Also good.

<Pumping optical fiber insertion step (second step)>
The pumping optical fiber is inserted into the pipe material 11 by the same method as the second step in the first embodiment.

  As in the case of the first embodiment, from the viewpoint of preventing the excitation optical fiber from being inserted into the capillary 20, there are a plurality of differences between the inner diameter of the capillary 20 and the outer diameter of the insertion body into the capillary 20. The outer diameter of the pumping optical fiber 17 is preferably smaller than the outer diameter of the pumping optical fiber 17 having the smallest diameter. Here, the outer diameter of the insertion body into the capillary 20 is the outer diameter of the spacer pipe 19. .

<Melting and cutting step>
By the same method as the melt cutting step in the first embodiment, the pipe material 11 from which the capillary 20 has been removed is heated and integrated, and the melted portion is cut.

  The optical combiner 10 obtained by the above manufacturing method has a gap between the signal optical fiber 16 and the excitation optical fiber 17 because, for example, the number of the excitation optical fiber cores 13 is seven or more. Since the spacer pipe 19 is arranged in the gap, it is possible to melt and integrate by heating. According to the method for manufacturing the optical combiner 10 as described above, the capillary 20 is inserted into the pipe material 11 and the capillary 20 is inserted with the signal optical fiber 16 inserted into the spacer pipe 19 from one end side thereof. As a result, the signal optical fiber 16 is reliably positioned at the center of the pipe material 11, so that when the signal optical fiber 16 and the excitation optical fiber 17 are inserted into the pipe material 11, the signal optical fiber 16 starts from the center. Therefore, the optical combiner 10 can be easily manufactured with high yield.

  As described above, the present invention is composed of one signal optical fiber and a plurality of pumping optical fibers, and a plurality of the end portions of the signal optical fibers are surrounded by the signal optical fiber as a center. This is useful for a method of manufacturing an optical combiner in which the excitation optical fibers are integrated.

It is a perspective view of the optical combiner of this Embodiment 1. FIG. 2 is a cross-sectional view taken along line A-A ′ in FIG. 1. It is a front view of the arrow B in FIG. FIG. 3 is an explanatory diagram illustrating a method for manufacturing the optical combiner according to the first embodiment. FIG. 10 is an explanatory diagram illustrating a method for manufacturing the optical combiner according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical combiner 11 Pipe material 16 Signal optical fiber 17 Excitation optical fiber 20 Capillary

Claims (9)

It is composed of one signal optical fiber and a plurality of pumping optical fibers, and the plurality of pumping optical fibers are arranged so as to surround the signal optical fiber around the signal optical fiber at the tip portion thereof. A method of manufacturing an integrated optical combiner,
A first step of inserting a capillary into the pipe material and inserting a signal optical fiber into the capillary from one end thereof;
The signal optical fiber is inserted and extended from one end side of the pipe member and is inserted into and held by the capillary inserted into the pipe member, and a plurality of excitations are provided to the pipe member from one end side thereof. A second step of inserting an optical fiber for use;
An optical combiner manufacturing method comprising: In the manufacturing method of the optical combiner described in Claim 1,
In the first step, after the capillary is inserted into the pipe member, the signal optical fiber is inserted into the capillary inserted into the pipe member. In the manufacturing method of the optical combiner described in Claim 2,
In the first step, the capillary is inserted into the pipe material in a penetrating state. In the manufacturing method of the optical combiner in any one of Claims 1 thru | or 3,
In the second step, the capillary in which the signal optical fiber is inserted is moved to the other end side of the pipe material. In the manufacturing method of the optical combiner described in Claim 4,
In the second step, the signal optical fiber is guided and introduced into the pipe member by moving the capillary to the other end side of the pipe member, and the method of manufacturing an optical combiner. In the manufacturing method of the optical combiner in any one of Claims 1 thru | or 5,
In the second step, an end face of the plurality of optical fibers for excitation is brought into contact with an end face of the capillary. In the manufacturing method of the optical combiner in any one of Claims 1 thru | or 6,
A method of manufacturing an optical combiner, wherein the capillary is inserted with the signal optical fiber inserted through a spacer pipe. In the manufacturing method of the optical combiner in any one of Claims 1 thru | or 7,
An optical combiner characterized in that the difference between the inner diameter of the capillary and the outer diameter of the insertion body of the capillary is smaller than the outer diameter of the smallest pumping optical fiber among the plurality of pumping optical fibers. Method. In the manufacturing method of the optical combiner in any one of Claims 1 thru | or 8,
A method of manufacturing an optical combiner, wherein a difference between an inner diameter of the pipe material and an outer diameter of the capillary is smaller than an outer diameter of a minimum excitation optical fiber among the plurality of excitation optical fibers.

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