JP2009004539A - Fiber laser oscillator and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber laser oscillator with a more efficient and simpler structure and with high output and to provide a method of manufacturing the fiber laser oscillator. <P>SOLUTION: An optical fiber for fiber laser 10 is spirally wound. An outgoing face of one exciting light guide fiber 20 is bonded to the optical fiber for fiber laser 10 in n-th winding ((n) is arbitrary integer of one or above) so that respective outgoing faces of a plurality of exciting light guide fibers 20 where exciting light is guided follow a winding direction of the wound optical fibber for fiber laser 10. The exciting light guide fiber 20 is bonded to the optical fiber for fiber laser 10 by a prescribed angle so that guided exciting light is confined in a bonding place. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fiber laser oscillator including a fiber laser optical fiber that generates laser oscillation light when a core member provided therein is excited by excitation light, and a pump light source, and a method for manufacturing the fiber laser oscillator.

Conventionally, various fiber laser oscillators have been proposed that can obtain very high quality laser light with high efficiency by using excitation light having relatively poor beam quality.
For example, in the prior art described in Patent Document 1, the pumping light guide fiber 20 having a gradual taper portion T is provided on the side surface of the fiber laser optical fiber 10 as shown in FIG. And a structure in which the excitation light Lin is incident from the excitation light guide fiber 20 after being fused (joined).
Further, for example, in the prior art described in Patent Document 2, as shown in FIG. 8B, a fiber laser optical fiber 10 is spirally wound and an excitation light core member 150 having a predetermined refractive index is used. The winding portion is hardened and formed into a cylindrical shape, and the excitation light Lin from the excitation light source 34 is guided into the excitation light core member 150 using a substantially flat light guide member 140.
Japanese Patent No. 3337691 JP 2006-019490 A

In recent years, higher output laser light is desired, and in order to increase the output laser light, more pump light must be incident on the optical fiber 10 for fiber laser.
In the prior art described in Patent Document 1, in order to increase the output laser light, pumping light guide fibers 20 are joined to a plurality of positions in the longitudinal direction of the optical fiber 10 for fiber laser, and each pumping light guide fiber 20 is joined. The excitation light source must be placed in In this case, the pumping light guide fiber 20 must be joined at an interval necessary for pumping the guided pumping light to pump the core member 12 in the fiber laser optical fiber 10 (pumping light is absorbed). . In addition, since the area of the joining part of the taper part T is large, it takes much time to join the plurality of pumping light guide fibers 20. Further, when the laser oscillator is housed in the housing, the arrangement of the plurality of excitation light sources, the wiring of the plurality of excitation light guide fibers 20 and the like are likely to be complicated.
In the prior art described in Patent Document 2, in order to increase the output laser light, the number of excitation light sources 34 and light guide members 140 may be increased. However, in the technique described in Patent Document 2, the excitation light is not incident on the optical fiber 10 for the fiber laser, and the excitation light is incident on the excitation light core member 150 including the optical fiber 10 for the fiber laser. Compared with Patent Document 1, the efficiency is low. Further, in Patent Document 2, it is ideal that the fiber laser optical fiber 10 is included in the pumping light core member 150, but a specific manufacturing method thereof is not disclosed.
The present invention has been made in view of such points, and it is an object of the present invention to provide a fiber laser oscillator and a method for manufacturing the fiber laser oscillator that can achieve higher output with a more efficient and simpler configuration. To do.

As means for solving the above-mentioned problems, a first invention of the present invention is a fiber laser oscillator as described in claim 1.
The fiber laser oscillator according to claim 1 has a core member that generates laser oscillation light when excited by excitation light in a longitudinal direction, and the incident excitation light is contained in a cladding member that covers the periphery of the core member. A fiber laser comprising: an optical fiber for a fiber laser confined and guided; a plurality of pumping light sources; and a plurality of pumping light guide fibers guided by the pumping lights emitted from the pumping light sources. It is an oscillator.
The optical fiber for a fiber laser is spirally wound and formed into a cylindrical shape, and each of the emission surfaces of the plurality of excitation light guide fibers is wound around the wound optical fiber for a fiber laser. The exit surface of one pumping light guide fiber is joined to the optical fiber for the n-th turn (n is an arbitrary integer equal to or greater than 1) so as to follow the direction, and pumping is performed at the joint. The excitation light guide fiber is joined to the fiber laser optical fiber at a predetermined angle so that the excitation light guided from the light guide fiber to the fiber laser optical fiber is confined in the cladding member.

According to a second aspect of the present invention, there is provided a fiber laser oscillator according to the second aspect.
A fiber laser oscillator according to a second aspect is the fiber laser oscillator according to the first aspect, wherein a plurality of the joint portions where the emission surfaces of the excitation light guide fiber are joined are formed in a cylindrical shape. The fiber laser optical fibers are arranged in a line so as to be parallel to the axis of the cylinder, and are arranged in every m turns (m is an arbitrary integer of 1 or more) of the fiber laser optical fibers.

According to a third aspect of the present invention, there is provided a fiber laser oscillator as set forth in the third aspect.
The fiber laser oscillator according to claim 3 is the fiber laser oscillator according to claim 1 or 2, wherein the wound optical fiber for the fiber laser has a predetermined refractive index including the junction. It is hardened in a cylindrical shape with a solidifying agent.

According to a fourth aspect of the present invention, there is provided a fiber laser oscillator as set forth in the fourth aspect.
A fiber laser oscillator according to a fourth aspect is the fiber laser oscillator according to any one of the first to third aspects, wherein the optical fiber for a fiber laser wound in a spiral shape has a predetermined refractive index. A rod-shaped body or a rod-shaped body having a coating that totally reflects the excitation light is wound around the outer peripheral surface.

A fifth invention of the present invention is a method for manufacturing a fiber laser oscillator as described in claim 5.
A method for manufacturing a fiber laser oscillator according to claim 5 is a method for manufacturing a fiber laser oscillator according to claim 3.
A substantially cylindrical cylindrical jig having a variable diameter is used, the diameter of the cylindrical jig is set to a predetermined diameter, and an intermediate member is dissolved on the outer peripheral surface of the cylindrical jig with a predetermined solvent. A step of forming a layer, a step of spirally winding the optical fiber for fiber laser from above the intermediate layer, and an exit surface of the excitation light guide fiber on the wound optical fiber for fiber laser. A step of bonding, a step of applying the solidifying agent to the wound optical fiber for the fiber laser including the bonding portion, and solidifying a wound portion of the optical fiber for the fiber laser into a cylindrical shape, and The intermediate member forming the intermediate layer is dissolved with a predetermined solvent, the diameter of the cylindrical jig is reduced, and the fiber laser optical fiber wound around the fiber laser is solidified in a cylindrical shape. Extracting the cylindrical jig; To.

A sixth invention of the present invention is a method for manufacturing a fiber laser oscillator as described in claim 6.
A manufacturing method of a fiber laser oscillator according to a sixth aspect is a manufacturing method of the fiber laser oscillator according to a third aspect.
Using a substantially cylindrical cylindrical jig that dissolves in a predetermined solvent, the step of spirally winding the fiber laser optical fiber from above the cylindrical jig, and the wound optical fiber for the fiber laser A step of bonding each of the exit surfaces of the pumping light guide fiber, and applying the solidifying agent to the wound optical fiber for the fiber laser, including the joint, and winding the optical fiber for the fiber laser. And a step of solidifying the portion into a cylindrical shape, and a step of dissolving the cylindrical jig with the predetermined solvent.

In the fiber laser oscillator according to claim 1, for example, when six pumping light guiding fibers are used, the first, second, third, fourth and fourth windings of the fiber laser optical fiber wound in a spiral shape Each of the excitation light guide fibers is bonded to the fifth and sixth rolls.
As described above, the pumping light is directly guided into the optical fiber for the fiber laser, which is efficient.
Further, as shown in the example of FIG. 1, the excitation light source 34 and the excitation light guide fiber 20 can be simply combined without being complicated. Furthermore, as shown in the example of FIG. 6, it is easy to add the excitation light unit 30 including the excitation light guiding fiber 20, and high output is easy.

In the fiber laser oscillator according to the second aspect, the joining operation can be performed more efficiently by arranging the joining portions in a line.
In addition, by joining the pumping light guide fiber for every m turns of the fiber laser optical fiber, the length required for pumping the light guided into the fiber laser optical fiber to pump the core member can be easily achieved. Can be secured. Thereby, the diameter of a cylindrical shape can be made smaller.

  Further, in the fiber laser oscillator according to claim 3, since the wound optical fiber for the fiber laser including the joint portion between the optical fiber for the fiber laser and the pumping light guiding fiber is solidified with a solidifying agent, Since the optical fiber and the junction can be appropriately protected, scratches and breakage can be prevented.

  The fiber laser oscillator according to claim 4 is a structure in which a fiber laser optical fiber is wound around a rod-shaped body having a refractive index that does not leak excitation light or a rod-shaped body that has been subjected to total reflection coating. Can be realized easily.

  Moreover, according to the manufacturing method of the fiber laser oscillator of Claim 5 or 6, the fiber laser oscillator of Claim 3 can be manufactured easily.

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a schematic external view (perspective view) of an embodiment of a fiber laser oscillator 1 according to the present invention. 2 shows a view (side view) of the fiber laser oscillator 1 shown in FIG. 1 viewed from the Y-axis direction.
1 to 6 described in the present embodiment, the X axis, the Y axis, and the Z axis are orthogonal to each other, and the Y axis indicates a direction parallel to the rotation axis of the cylindrical portion 50. And the Z axis indicate the direction orthogonal to the cylindrical portion 50. The Z-axis indicates the direction parallel to the excitation light guide fiber 20 at the joint S (see FIG. 2) between the fiber laser optical fiber 10 and the excitation light guide fiber 20 on the cylindrical portion 50.

● [Configuration of Fiber Laser Oscillator 1 (FIGS. 1 and 2)]
The fiber laser oscillator 1 includes a cylindrical portion 50 in which a fiber laser optical fiber 10 is spirally wound along an outer peripheral surface of a cylinder having a predetermined diameter and formed into a cylindrical shape, and excitation light emitted from an excitation light source 34. Is provided to each of the excitation light guide fibers 20.
The optical fiber 10 for fiber laser has a core member 12 (a core member doped with a rare earth element) that generates laser oscillation light when excited by excitation light in the longitudinal direction, and the periphery of the core member 12 is excited. It is covered with a clad member 14 that confines and guides light.
In the fiber laser oscillator 1 shown in the example of FIGS. 1 and 2, the generated output laser beam Lout is provided at one end on the side from which the output laser beam Lout is extracted in the fiber laser optical fiber 10 wound in a spiral shape. Reflecting means FBG2 (for example, a fiber Bragg grating having a transmittance of several percent) is provided that reflects part of the light beam in the direction of the other end and transmits the remaining light. Further, the other end of the fiber laser optical fiber 10 is provided with a reflecting means FBG1 (for example, a fiber Bragg grating having a transmittance of 0%) that totally reflects the generated output laser light Lout in the direction of the one end.
In order to maintain the shape of the wound fiber laser optical fiber 10, the cylindrical portion 50 including the joining portion S is replaced with a solidifying agent 80 (light-transmitting ultraviolet curable resin or quartz such as polysiloxane, polysilane, or polysilazane). It is preferable to fix it with a resin.
Moreover, as shown in FIG.1 and FIG.2, in this Embodiment, the outer peripheral side of the cylindrical part 50 is hardened with the solidification material 80, and the inside of the cylindrical part 50 is formed hollow.
The solidifying agent 80 may be omitted as long as the shape of the wound fiber laser optical fiber 10 can be maintained.

The pumping light unit 30 includes a pumping light source 34 including a plurality of light sources, and a plurality of pumping light guide fibers 20 through which pumping light emitted from the pumping light source 34 is guided.
In the example of FIGS. 1 and 2, a semiconductor laser is used as the pumping light, and the pumping light source 34 is a semiconductor laser array in which a plurality of light emitting units are arranged in the minor axis direction (Y-axis direction in FIG. 1) of the pumping light. Used.
The incident surface of the pumping light guide fiber 20 is disposed so as to face each light emitting portion of the semiconductor laser array, and the emitting surface of the pumping light guide fiber 20 is bonded to the side surface of the wound fiber laser optical fiber 10. ing. With this configuration, the excitation light emitted from one light emitting unit is guided to one excitation light guide fiber 20, and the guided excitation light is guided to the fiber laser optical fiber 10.
In this case, since the semiconductor laser light emitted from the light emitting unit spreads in an elliptical shape, the major axis direction of the ellipse (X-axis direction in FIGS. 1 and 2) or the incident surface of the excitation light guide fiber 20 or A lens for condensing excitation light in the major axis direction and the minor axis direction (Y-axis direction in FIGS. 1 and 2) is integrally formed (not shown).
The excitation light unit 30 shown in the example of FIGS. 1 and 2 positions and fixes the excitation light source 34 and the excitation light light guide fiber 20 and also dissipates heat, and a holding plate 33 that fixes the excitation light light guide fiber 20. However, the excitation light unit 30 is not limited to the one described above, and any excitation light unit can be used as long as the excitation light can be guided to each of the plurality of excitation light guide fibers 20. There are no particular restrictions on the type, configuration, shape, etc. of the excitation light unit 30.

● [Joint angle of excitation light guide fiber 20 (FIG. 3) and joint location (FIG. 4)]
The diameter D (see FIGS. 1 and 2) of the cylindrical portion 50 is set to a size that provides a curvature capable of confining and propagating the pumping light guided in the wound fiber laser optical fiber 10. It is set according to the refractive index of the clad member 14, the spread angle of the excitation light guided into the excitation light guide fiber 20, and the like.
As shown in the example of FIG. 3A, the optical fiber 10 for a fiber laser covers the periphery of the core member 12 with a first cladding member 14 having a predetermined refractive index, and further surrounds the periphery of the first cladding member 14 with the first cladding member 14. A so-called double clad fiber covered with a second clad member 16 having a refractive index smaller than the refractive index of the first clad member 14 or a so-called second clad member 16 is omitted as shown in the example of FIG. A single clad fiber can be used.

The excitation light guiding fiber 20 includes a light guiding core member 22 and a clad member 24 that covers the periphery of the light guiding core member 22. 3A and 3B, the periphery of the clad member 24 is covered with a protective coating 28, and the coating 28 is removed at the junction with the optical fiber 10 for the fiber laser. However, the coating 28 may be omitted (all removed).
In the excitation light guiding fiber 20, the refractive index of the cladding member 24 is set smaller than that of the light guiding core member 22 in order to confine the excitation light in the light guiding core member 22.
In the optical fiber 10 for fiber laser, in order to confine the excitation light in the (first) cladding member 14, the refractive index of the second cladding member 16 is higher than the refractive index of the first cladding member 14 in the example of FIG. The refractive indexes of the clad members 14 and 16 are set so as to be smaller. In the example of FIG. 3B, the refractive index of the clad member 14 is set so that the environment (in this case, the atmosphere) around the clad member 14 is smaller than the refractive index of the (first) clad member 14. Is set.

3A and 3B, the light guide core member 22 of the pumping light guide fiber 20 is joined to the (first) clad member 14 of the optical fiber 10 for fiber laser, and the refractive indexes of each other. Are set almost the same.
With the above refractive index setting, the angle θ at the junction between the light guide core member 22 of the pumping light guide fiber 20 and the (first) clad member 14 of the optical fiber 10 for fiber laser is shown in FIG. In FIG. 3B, settings are made as follows.
In the case of the double clad fiber shown in FIG. 3A, the angle θ is set to satisfy “the angle θ <the critical angle between the (first) clad member 14 and the (second) clad member 16”.
Further, in the case of the single clad fiber of FIG. 3B, “the angle θ <(first) critical angle between the clad member 14 and the surrounding layer (coating when coated, air when not coated)” Set as follows.

Next, with reference to FIGS. 4A and 4B, a joint portion between the pumping light guide fiber 20 and the fiber laser optical fiber 10 will be described.
Each of the exit surfaces of the pumping light guide fiber 20 has an n-th turn (n is an arbitrary number of 1 or more) so as to be along the winding direction of the wound fiber laser optical fiber 10 (parallel to the Z-axis direction). The exit surface of one pumping light guide fiber 20 is joined to an optical fiber 10 for an integer) fiber laser.
For example, as shown in the example of FIG. 4A, when six pumping light guide fibers 20 are joined, each pumping light guide fiber 20 is emitted to the optical fiber 10 for the fiber lasers n to n + 5. The surfaces are joined.
In this case, the excitation light incident on the optical fiber 10 for the n-th fiber laser fiber reaches the joining location S of the (n + 1) -th turn when the round of the cylindrical portion 50 is made. In a preferred embodiment, it is preferable that the next excitation light is incident from a position where all the incident excitation light is absorbed (position used for excitation). Therefore, in the example shown in FIG. 4A, there is a possibility that the diameter D of the cylindrical portion 50 has to be increased, which is not preferable because the size of the fiber laser oscillator 1 is increased.

Therefore, as shown in the example of FIG. 4B, the pumping light guide fiber 20 is joined every m turns (m is an arbitrary integer equal to or greater than 1) of the optical fiber 10 for fiber laser (in FIG. 4B). In the example, it is joined every 3 volumes). According to this configuration, it is possible to secure a length in which all of the incident excitation light is absorbed without increasing the diameter D of the cylindrical portion 50. Thereby, the diameter D of the fiber laser oscillator 1 can be further reduced. In the example of FIG. 4B, the excitation light guide fibers 20 are joined at equal intervals for every m turns, but may be joined at unequal intervals.
It should be noted that it is convenient to perform the joining process in a short time as will be described later if the joining portions S are joined in a line so as to be parallel to the axis of the cylindrical portion 50.
Further, the winding interval of the fiber laser optical fiber 10 to be wound is preferably spaced so that the excitation light does not enter the adjacent winding portion. Since the contact portion with the fiber 10 is in a linear state (because it is a fiber having a circular cross section), the possibility that the excitation light is incident on the adjacent winding portion is very small. Since it is small, it may be wound without a gap.

● [Manufacturing method of fiber laser oscillator 1 (FIG. 5)]
Next, a manufacturing method of the fiber laser oscillator 1 described above will be described with reference to FIG.
First, a substantially cylindrical jig EJ having a variable diameter D is prepared. The cylindrical jig EJ shown in the example of FIG. 5 is hollow, and a split part WB (gap part) is formed in the axial direction, and the diameter D can be reduced by tightening the screw B to reduce the gap of the split part WB. However, the cylindrical jig EJ is not limited to this structure. Any structure may be used as long as the diameter D can be made variable.

In the first step (A), the diameter D of the cylindrical jig EJ is set so as to be relatively large, and the intermediate member 70 is dissolved on the outer peripheral surface of the cylindrical jig EJ with a predetermined solvent (for example, water). To form an intermediate layer. For example, a water-soluble sheet or film is used as the intermediate member 70, and the water-soluble sheet or film is wound around the outer peripheral surface of the cylindrical jig EJ to form the intermediate layer.
In the next step (B), the fiber laser optical fiber 10 is spirally wound from above the intermediate layer. In the example of FIG. 5B, a fiber laser optical fiber 10 provided with reflecting means FBG1 and FBG2 at one end and the other end is wound.
In the next step (C), each emission surface of the pumping light guide fiber 20 of the pumping light unit 30 is joined to the wound fiber laser optical fiber 10. For joining, for example, melt joining can be performed using a CO ₂ laser. Since the joints S are arranged in a line in a direction parallel to the axis of the cylindrical jig EJ, the cylindrical jig EJ and the excitation light unit 30 and the CO ₂ laser emitting portion C are relatively connected to the cylindrical jig EJ. By emitting the CO ₂ laser beam L and joining it while moving in the axial direction, joining can be performed in a shorter time. Note that a transparent resin or the like may be used instead of the CO ₂ laser bonding.

  In the next step (D), the wound portion (cylindrical portion) of the wound fiber laser optical fiber 10 including the joint portion between the fiber laser optical fiber 10 and the pumping light guiding fiber 20 is subjected to predetermined refraction. A solidified layer is formed using a solidifying agent 80 having a rate, and solidified into a cylindrical shape. For example, as the solidifying agent 80, a light transmissive ultraviolet curable resin or a quartz resin such as polysiloxane, polysilane, or polysilazane is used. The refractive index of the solidifying agent 80 may be any refractive index particularly when the fiber laser optical fiber 10 is a double clad. In the case of a single clad, the refractive index is smaller than that of the (first) clad member 14. In the end, since the atmosphere around the solidifying agent 80 is the atmosphere, a refractive index equivalent to that of the cladding member 14 may be used as long as the refractive index is higher than the refractive index of the atmosphere. The refractive index may be larger than that of the clad member 14.

Here, FIG. 5F shows a cross section at the time when the process (D) is completed. From the inside, a cylindrical jig EJ (formed hollow), an intermediate layer formed by the intermediate member 70, a wound fiber laser optical fiber 10, and a solidified layer formed by the solidifying agent 80 are formed. In addition, since the joining part S of the optical fiber 10 for fiber laser and the excitation light light guide fiber 20 is covered and protected by the solidifying agent 80, the joining part S can be prevented from being broken or disconnected.
In the next step (E), the intermediate member 70 is dissolved with a predetermined solvent, the diameter D of the cylindrical jig EJ is set to be small with the screw B, and the cylindrical jig EJ is extracted. Thereby, the intermediate member 70 and the cylindrical jig EJ are removed from the state of FIG. In addition, if a plurality of holes and slits penetrating from the outer peripheral surface to the inner peripheral surface are formed on the side surface of the cylindrical jig EJ, a predetermined solvent is also formed from the inner wall side formed hollow in the cylindrical jig EJ. Since the intermediate member 70 can be dissolved, it can be dissolved in a shorter time.

In the above description, the intermediate member 70 that dissolves with a predetermined solvent is used. However, if the cylindrical jig EJ is made of a material that dissolves with a predetermined solvent, the intermediate member 70 can be omitted. In this case, the diameter of the cylindrical jig EJ may not be variable.
In the first step, the fiber laser optical fiber 10 is wound around the outer peripheral surface of the cylindrical jig EJ as in the step (B).
In the next step, as in the step (C), the respective emission surfaces of the pumping light guide fiber 20 of the pumping light unit 30 are joined to the wound fiber laser optical fiber 10.
In the next step, like the step (D), the winding portion is solidified with a solidifying agent 80 and solidified into a cylindrical shape.
In the next step, the cylindrical jig EJ is dissolved and removed with a predetermined solvent. In addition, if a hole or a slit penetrating from the outer peripheral surface to the inner peripheral surface is provided on the side surface of the cylindrical jig EJ, the cylindrical jig EJ can be dissolved in a shorter time.

According to the manufacturing method described above, since the cylindrical jig around which the fiber laser optical fiber 10 is wound can be removed, the fiber laser optical fiber 10 is in contact with the solidifying agent 80 or the atmosphere. If the optical fiber 10 for fiber laser is in contact with another member, light (in this case, excitation light) may leak from the member, but in this embodiment, a solidifying agent (having a predetermined refractive index) Since it is 80 or the atmosphere (with a predetermined refractive index), light does not leak and the laser oscillation efficiency can be further improved.
Further, since the single-clad fiber laser optical fiber 10 with the coating removed can be used, it can be realized at a low cost. Furthermore, since the cylindrical part from which the coating has been peeled can be protected by the solidifying agent 80, the fiber laser optical fiber 10 can be prevented from being damaged or damaged.

● [Example of high output (Fig. 6)]
Next, an example of increasing the output of the fiber laser oscillator 1 shown in FIG. 1 will be described with reference to FIG. The example of FIG. 6 includes two pumping light units 30 and increases the output of the output laser light Lout compared to the example of FIG. In order to further increase the output, the third and fourth excitation light units 30 may be added in the same manner, so that the output can be easily increased. Further, compared to the conventional fiber laser oscillator described with reference to FIG. 8A, even if the pumping light guide fiber 20 and the pumping light source 34 are increased, the fiber can be easily housed in a compact form without being complicated. A laser oscillator can be constructed.
In the example of FIG. 6, the output laser light Lout is converted into parallel light by the collimator lens 90 and condensed by the condenser lens 92 so that the diameter is reduced, thereby increasing the density of the laser light.
In the example of FIG. 6, the excitation light units 30 are arranged in parallel in the axial direction of the cylindrical portion 50, but the excitation light units 30 may be arranged radially with the axis of the cylindrical portion 50 as the center (the heat radiation table 31 is provided). Effective when the size is increased).

[Example of the fiber laser oscillator 1 in which the cylindrical body 95 around which the optical fiber 10 for fiber laser is wound is left (FIG. 7)]
In the method of manufacturing the fiber laser oscillator 1 using FIG. 5 described above, the inner side of the wound fiber laser optical fiber 10 is hollow by extracting or melting the cylindrical jig EJ. The fiber laser optical fiber 10 may be wound around 95 to leave the cylinder 95 as it is (see FIG. 7).
In this case, the cylindrical body 95 is formed of a material having a predetermined refractive index (preferably a refractive index smaller than that of the clad member 14 of the optical fiber for fiber laser 10) or the excitation light so as not to leak the incident excitation light. Is coated on the outer peripheral surface.
The wound portion (cylindrical portion) of the wound fiber laser optical fiber 10 is solidified with a solidifying agent 80 (light transmissive ultraviolet curable resin or quartz resin such as polysiloxane, polysilane, or polysilazane). It is preferable to fix them. The shape of the cylindrical body 95 is not limited to a cylindrical shape having a hollow inside, and may be any shape as long as it is a rod-shaped body around which the fiber laser optical fiber 10 can be wound, such as a cylindrical shape. . For example, even if it is a quadrangular prism, the fiber laser optical fiber 10 may be wound in a cylindrical shape so as to be in contact with only the four corners of the quadrangular prism.

The fiber laser oscillator 1 of the present invention is not limited to the appearance, configuration, structure, and the like described in the present embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention.
In the present embodiment, the example of the configuration including the reflection means FBG1 and FBG2 has been described, but the reflection means FBG2 may be omitted. Further, the reflection means FBG1 may be reflected back by an optical reflection means such as a concave mirror. When the generated output laser light Lout is taken out from both ends of the fiber laser optical fiber 10, the reflection means FBG1 and FBG2 can be omitted.

It is a perspective view explaining one embodiment of fiber laser oscillator 1 of the present invention. It is the figure which looked at the fiber laser oscillator 1 shown in FIG. 1 from the Y-axis direction. It is a figure explaining the junction part S of the optical fiber 10 for fiber lasers, and the excitation light light guide fiber 20. FIG. It is a figure explaining the junction part S of the optical fiber 10 for fiber lasers, and the excitation light light guide fiber 20. FIG. FIG. 5 is a diagram for explaining a method for manufacturing the fiber laser oscillator 1. It is a figure explaining the example which raises the output of the fiber laser oscillator. It is a figure explaining the example which comprised the fiber laser oscillator 1 which wound the optical fiber 10 for fiber lasers in the cylinder 95. FIG. It is a figure explaining the example of the conventional fiber laser oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiber laser oscillator 10 Optical fiber for fiber lasers 12 Core member 14 (1st) Clad member 16 (2nd) Clad member 20 Excitation light guide fiber 22 Light guide core member 24 Clad member 28 Coating 30 Excitation light unit 34 Excitation light source 50 Cylindrical part 70 Intermediate member 80 Solidifying agent 95 Cylindrical body EJ Cylindrical jig S Joint location FBG1, FBG2 Reflecting means

Claims (6)

An optical fiber for a fiber laser having a core member that generates laser oscillation light in the longitudinal direction when excited by excitation light, and confining and guiding incident excitation light in a cladding member that covers the periphery of the core member; ,
A plurality of excitation light sources;
A plurality of pumping light guide fibers guided by each pumping light emitted from each of the plurality of pumping light sources, and a fiber laser oscillator comprising:
The optical fiber for the fiber laser is spirally wound and formed into a cylindrical shape,
Each of the exit surfaces of the plurality of pumping light guide fibers has an n-th (n is an arbitrary integer greater than or equal to 1) fiber laser so as to be along the winding direction of the wound optical fiber for a fiber laser. The exit surface of one pumping light guide fiber is bonded to the optical fiber, and the pumping light guided from the pumping light guide fiber to the fiber laser fiber is confined in the cladding member at the joint. The excitation light guide fiber is bonded at a predetermined angle to the fiber laser optical fiber,
Fiber laser oscillator. The fiber laser oscillator according to claim 1,
The plurality of joint portions where the emission surfaces of the excitation light guiding fibers are joined are arranged in a row so as to be parallel to the axis of the cylinder in the optical fiber for a fiber laser formed in a cylindrical shape. , Arranged every m turns (m is an arbitrary integer of 1 or more) of the optical fiber for the fiber laser,
Fiber laser oscillator. The fiber laser oscillator according to claim 1 or 2,
The wound optical fiber for a fiber laser is solidified in a cylindrical shape with a solidifying agent having a predetermined refractive index, including the joint portion.
Fiber laser oscillator. The fiber laser oscillator according to any one of claims 1 to 3,
The optical fiber for a fiber laser wound in a spiral shape is wound around a rod-shaped body having a predetermined refractive index, or a rod-shaped body having a coating that totally reflects the excitation light applied to the outer peripheral surface.
Fiber laser oscillator. A method of manufacturing a fiber laser oscillator according to claim 3,
Using a substantially cylindrical jig whose diameter is variable,
Setting the diameter of the cylindrical jig to a predetermined diameter, and forming an intermediate layer with an intermediate member dissolved in a predetermined solvent on the outer peripheral surface of the cylindrical jig;
Spirally winding the fiber laser optical fiber from above the intermediate layer;
Bonding each of the exit surfaces of the excitation light guide fiber to the wound fiber laser optical fiber;
Applying the solidifying agent to the wound optical fiber for the fiber laser, including the joint, and solidifying the wound portion of the optical fiber for the fiber laser into a cylindrical shape;
The intermediate member forming the intermediate layer is dissolved with the predetermined solvent, and further, the diameter of the cylindrical jig is reduced, and from the winding portion of the optical fiber for fiber laser that is solidified in a cylindrical shape Withdrawing the cylindrical jig,
Manufacturing method of fiber laser oscillator. A method of manufacturing a fiber laser oscillator according to claim 3,
Using a substantially cylindrical cylindrical jig that dissolves in a predetermined solvent,
A step of spirally winding the optical fiber for a fiber laser from above the cylindrical jig;
Bonding each of the exit surfaces of the excitation light guide fiber to the wound fiber laser optical fiber;
Applying the solidifying agent to the wound optical fiber for the fiber laser, including the joint, and solidifying the wound portion of the optical fiber for the fiber laser into a cylindrical shape;
Dissolving the cylindrical jig with the predetermined solvent,
Manufacturing method of fiber laser oscillator.

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