JP2013008856A - Fiber protection structure, laser processing device and fiber protection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber protection structure that can suppress influence of heat generation of a fiber at the adhesion portion between the fiber and a protection member.SOLUTION: In a first connection portion 24, the amount of generated heat of a fiber at the adhesion portion between a dope fiber D and a sleeve 41 is larger than that at the adhesion portion between a first transmission fiber F1 and the sleeve 41, and the width T2 in the longitudinal direction of adhesive agent G2 at the dope fiber D side is smaller than the width T1 in the longitudinal direction of adhesive agent G1 at the first transmission fiber F1 side. In a second connection portion 25, the amount of generated heat of the fiber at the adhesion portion between a second transmission fiber F2 and a sleeve 42 is larger than that at the adhesion portion between the dope fiber D and the sleeve 42, and the width T4 in the longitudinal direction of adhesive agent G4 at the second transmission fiber F2 side is smaller than the width T3 in the longitudinal direction of adhesive agent G3 at the dope fiber D side.

Description

  The present invention relates to a protective structure at a connection portion between fiber end portions.

  2. Description of the Related Art Conventionally, a fiber laser device has a connection portion between ends of two fibers made of different materials in an optical amplifier or the like. For example, in the configuration shown in Patent Literature 1, the ends of a pair of fibers are fused together, and the fused portions are protected by a protective member (a sleeve in Patent Literature 1). This protective member is bonded and fixed to each fiber with an adhesive.

JP 2003-315596 A

  However, in the fiber protection structure as described above, a problem related to the heat of the fiber occurs in the bonded portion between the fiber and the protective member, and if the heat accumulates in the bonded portion without radiating heat, the difference in thermal expansion coefficient of each fiber. As a result, there has been a problem that the optical loss at the fused portion between the fiber ends increases or the adhesive at the bonded portion is softened and the adhesive strength is reduced.

  The present invention has been made in order to solve the above-mentioned problems, and its object is to provide a fiber protection structure and a laser processing apparatus capable of minimizing the influence of fiber heat generation at the bonded portion of the fiber and the protection member. And providing a fiber protection method.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the end portions of the pair of fibers are fused together, and a protective member that is attached to the fused portion to protect the fused portion is the pair of fibers. A fiber protection structure in which a fiber is bonded to each of the fibers with an adhesive, and a fiber heat generation amount in a bonded portion between one of the fibers and the protective member is a fiber heat generation in a bonded portion between the other fiber and the protective member. The longitudinal width of the adhesive used for the adhesive portion having a larger fiber heating value than the amount is set smaller than the longitudinal width of the adhesive used for the other adhesive portion. It is characterized by that.

  In this invention, the longitudinal width of the adhesive used in the bonding portion between one fiber and the protection member and the bonding portion between the other fiber and the protection member, which has the larger calorific value, is the other. It is set to be smaller than the longitudinal width of the adhesive at the bonded portion. As a result, since the area where the fiber and the protective member are covered with the adhesive is reduced in the bonded portion where the heat generation amount of the fiber is larger, the heat generated in the bonded portion can be easily released. Thereby, it becomes possible to suppress the influence by the heat_generation | fever of the fiber in the adhesion part of a fiber and a protection member small.

  In addition, by setting the longitudinal width of the adhesive at the bonded portion where the heat generation amount of the fiber is smaller, the total length of the adhesive in the bonded portion between the protective member and the pair of fibers is set not to decrease. Therefore, it is possible to secure the fixing strength of the protective member for the pair of fibers (mainly the strength that can withstand the force in the longitudinal direction). As a result, it is possible to suppress the influence of heat generation of the fiber at the bonded portion between the fiber and the protective member while securing the fixing strength of the protective member to the fiber.

  According to a second aspect of the present invention, in the fiber protection structure according to the first aspect, the pair of fibers includes a doped fiber for optical amplification containing a rare earth element therein and a transmission fiber for transmitting light. It is characterized by that.

  In this invention, since the heat generated in the doped fiber or the transmission fiber is likely to increase due to the power of optical amplification, the longitudinal width of the adhesive used for the adhesive portion having the larger fiber heating amount is the same as that of the other adhesive portion. The heat dissipation effect by making it smaller than the longitudinal width of the adhesive can be made more effective.

  According to a third aspect of the present invention, in the fiber protection structure according to the first or second aspect, the protective member is a cylindrical sleeve so as to cover a fusion portion between the ends of the pair of fibers. It is characterized by extrapolation.

In this invention, since the fusion | melting part of the edge parts of a fiber is covered over a perimeter by a sleeve, the fusion | melting part of fibers can be protected more effectively.
The invention according to claim 4 is the fiber protection structure according to any one of claims 1 to 3, wherein the pair of fibers are made of quartz or glass, and the protection member is made of glass. And

  In the present invention, since a material having a thermal expansion coefficient close to that of the fiber and the protection member is used, the influence of the thermal expansion of the fiber and the protection member can be reduced. For example, when the fiber and the protective member are thermally expanded in the longitudinal direction due to the heat generated by the fiber, the positional deviation at the bonded portion between the fiber and the protective member is unlikely to occur, thereby preventing the occurrence of poor adhesion.

According to a fifth aspect of the present invention, in the fiber protection structure according to any one of the first to third aspects, the protective member is made of a metal material.
In this invention, since the protective member is made of a metal material excellent in heat dissipation, it is possible to efficiently release the heat generated in the fiber.

  The invention according to claim 6 is the fiber protection structure according to any one of claims 1 to 5, wherein the longitudinal width of the adhesive used for the adhesive portion having a larger fiber heating value is: It is set to 1/2 or less of the longitudinal width of the adhesive used for the other adhesive part.

  In this invention, when the longitudinal width of the adhesive at the bonding portion with the larger fiber heating value is set to a small width suitable for heat dissipation, the longitudinal width of the other adhesive is the bonding with the larger fiber heating value. It becomes more than twice the longitudinal width of the agent. For this reason, the total width of the adhesives can be increased, and the fixing strength of the protective member to the fiber can be more suitably ensured.

  According to the seventh aspect of the invention, the ends of the transmission fiber and the doped fiber for optical amplification containing the rare earth element are fused to each other, and are attached to the fused portion to protect the fused portion. A laser processing apparatus having a fiber protection structure in which a member, the transmission fiber, and the doped fiber are bonded to each other with an adhesive, and one of the transmission fiber and the doped fiber and the protective member The amount of heat generated by the fiber at the bonded portion is larger than the amount of heat generated by the fiber at the bonded portion between the other fiber and the protective member, and the longitudinal width of the adhesive used in the bonded portion with the larger amount of heat generated by the fiber. Is set to be smaller than the longitudinal width of the adhesive used for the other adhesive portion.

  In this invention, the longitudinal width of the adhesive having the larger amount of heat generated by the fiber at the transmission fiber-side bonded portion and the doped fiber-side bonded portion is set smaller than the longitudinal width of the adhesive at the other bonded portion. Is done. As a result, since the area where the fiber and the protective member are covered with the adhesive is reduced in the bonded portion where the heat generation amount of the fiber is larger, the heat generated in the bonded portion can be easily released. Thereby, it becomes possible to suppress the influence by the heat_generation | fever of the fiber in the adhesion part of a fiber and a protection member small.

  In addition, by setting the longitudinal width of the adhesive at the bonded portion where the heat generation amount of the fiber is smaller, the total length of the adhesive in the bonded portion between the protective member and the pair of fibers is set not to decrease. Therefore, it is possible to secure the fixing strength of the protective member to the fiber (mainly the strength that can withstand the force in the longitudinal direction). As a result, it is possible to suppress the influence of heat generation of the fiber at the bonded portion between the fiber and the protective member while securing the fixing strength of the protective member to the fiber.

  In addition, since the heat generated in the doped fiber or the transmission fiber is likely to increase due to the optical amplification power at the connection portion between the doped fiber and the transmission fiber, the adhesive used in the bonding portion having the larger fiber heating amount is used. The heat radiation effect by making the longitudinal width smaller than the longitudinal width of the adhesive of the other adhesive portion can be made more effective.

  The invention according to claim 8 is the laser processing apparatus according to claim 7, wherein the transmission fiber is connected to an incident side end portion of the doped fiber, and from the signal laser light and the excitation light source from the seed light source. The pumping light is transmitted to the doped fiber, and the heat generation amount of the fiber at the bonded portion between the doped fiber and the protection member is larger than the heat generation amount of the fiber at the bonded portion between the transmission fiber and the protection member. The longitudinal width of the adhesive on the doped fiber side is set smaller than the longitudinal width of the adhesive on the transmission fiber side.

  According to the present invention, at the connection portion between the doped fiber and the transmission fiber connected to the incident side of the doped fiber, the fixing strength of the protective member is secured, but the heat generated by the fiber at the bonded portion of the fiber and the protective member. It is possible to reduce the influence.

  A ninth aspect of the present invention is the laser processing apparatus according to the seventh aspect, wherein the transmission fiber is connected to an output side end of the doped fiber, and laser light amplified by the doped fiber is introduced. The heat generation amount of the fiber at the bonding portion between the transmission fiber and the protection member is larger than the heat generation amount of the fiber at the bonding portion between the doped fiber and the protection member, and the bonding on the transmission fiber side. The longitudinal width of the agent is set to be smaller than the longitudinal width of the adhesive on the doped fiber side.

  In the present invention, at the connection portion between the doped fiber and the transmission fiber connected to the outgoing side of the doped fiber, the fixing strength of the protective member is secured, but the heat generated by the fiber at the bonded portion of the fiber and the protective member. It is possible to reduce the influence.

  The invention according to claim 10 is a fiber in which ends of a pair of fibers are fused to each other, a protective member is attached to the fused portion, and the protective member and the pair of fibers are respectively bonded with an adhesive. In the protection method, a fiber heat generation amount at a bonding portion between one of the fibers and the protection member is larger than a fiber heat generation amount at a bonding portion between the other fiber and the protection member, and the fiber heat generation amount is large. The longitudinal width of the adhesive at one adhesive portion is set to be smaller than the longitudinal width of the adhesive at the other adhesive portion.

  In this invention, the longitudinal width of the adhesive used in the bonding portion between one fiber and the protection member and the bonding portion between the other fiber and the protection member, which has the larger calorific value, is the other. It is set to be smaller than the longitudinal width of the adhesive at the bonded portion. As a result, since the area where the fiber and the protective member are covered with the adhesive is reduced in the bonded portion where the heat generation amount of the fiber is larger, the heat generated in the bonded portion can be easily released. Thereby, it becomes possible to suppress the influence by the heat_generation | fever of the fiber in the adhesion part of a fiber and a protection member small.

  In addition, by setting the longitudinal width of the adhesive at the bonded portion where the heat generation amount of the fiber is smaller, the total length of the adhesive in the bonded portion between the protective member and the pair of fibers is set not to decrease. Therefore, it is possible to secure the fixing strength of the protective member for the pair of fibers (mainly the strength that can withstand the force in the longitudinal direction). As a result, it is possible to suppress the influence of heat generation of the fiber at the bonded portion between the fiber and the protective member while securing the fixing strength of the protective member to the fiber.

  Therefore, according to the above-described invention, it is possible to suppress the influence of heat generation of the fiber at the bonded portion between the fiber and the protection member.

The schematic block diagram which shows the laser processing apparatus of this embodiment. The schematic diagram which shows the fiber protection structure of this embodiment. The schematic diagram which shows the fiber protection structure of another example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the laser processing apparatus 10 according to the present embodiment includes a main body portion 11 and a head portion 12 connected to the main body portion 11 via a fiber cable 10a and an electric cable (not shown). .

  The main body 11 includes a seed light source 21 that outputs a signal laser beam. The seed light source 21 is connected to a first transmission fiber F1 that transmits the signal laser light output from the seed light source 21. The first transmission fiber F1 is made of, for example, quartz, and is made of a single clad fiber suitable for light transmission.

  The first transmission fiber F1 is provided with an optical coupling portion 22 made of a fiber coupler or the like. The first transmission fiber F1 is connected to the pumping light source 23 (laser diode) via the optical coupling unit 22, and the pumping light output from the pumping light source 23 passes through the optical coupling unit 22 for the first transmission. The light enters the fiber F1.

  A doped fiber D connected to the first transmission fiber F1 at the first connection portion 24 is disposed downstream of the first transmission fiber F1. The doped fiber D is made of, for example, quartz and is a flexible double-clad fiber containing a rare earth element such as ytterbium (Yb), and an optical path having a required length is secured by being wound around a bobbin (not shown). ing. The doped fiber D has an incident side end connected to the first transmission fiber F1 at the first connection portion 24, and an emission side end connected to the second transmission fiber F2 at the rear stage at the second connection portion 25. Has been.

  The second transmission fiber F2 is made of, for example, quartz and is made of a single clad fiber suitable for light transmission. The output end of the second transmission fiber F2 is connected to the input end of the fiber cable 10a via a fiber connector (not shown), and the laser light output from the second transmission fiber F2 is a fiber. The data is transmitted to the head unit 12 via the cable 10a.

Here, the aspect of the optical amplification having the above-described configuration will be described.
The excitation light output from the excitation light source 23 is incident on the first transmission fiber F1 through the optical coupling unit 22, and is incident on the doped fiber D from the first transmission fiber F1 through the first connection unit 24. . Then, the rare earth element in the doped fiber D is excited by the excitation light. In this state, when the signal laser light output from the seed light source 21 is incident on the doped fiber D via the first transmission fiber F1 and the first connection portion 24, the signal laser light is converted into the doped fiber D. Is amplified to a level at which printing on the workpiece W is possible. Then, the amplified light is incident on the second transmission fiber F2 via the second connection portion 25, and is transmitted from the second transmission fiber F2 to the head portion 12 via the fiber cable 10a.

  The head unit 12 includes a collimator lens 31 that squeezes the laser light L emitted from the fiber cable 10a into parallel light or convergent light. The laser beam focused through the collimator lens 31 is reflected in a required direction by the optical scanning mechanism 32 provided in the head unit 12. The optical scanning mechanism 32 is configured to include two galvanometer mirrors that reflect laser light, and the laser light focused through the collimator lens 31 is required by changing the inclination angle of each galvanometer mirror. Scanning in the direction of. The laser beam reflected by the optical scanning mechanism 32 is narrowed down to a spot laser beam by the condenser lens 33. Then, the narrowed laser beam L scans the surface of the workpiece W (processing object), whereby desired marking is performed.

  The control unit 20 provided in the main body unit 11 controls the output of the seed light source 21 via the driver 26 and also controls the output of the excitation light source 23 via the driver 27. The control unit 20 includes the head unit. The driving of the optical scanning mechanism 32 is controlled via a driver 34 provided in the circuit 12.

[Fiber protection structure]
In the laser processing apparatus 10 configured as described above, the protective structure (holding structure) of the fused portion between the first transmission fiber F1 and the doped fiber D in the first connection portion 24 and the doping in the second connection portion 25 The protection structure (holding structure) for the fused portion between the fiber D and the second transmission fiber F2 will be described with reference to FIG.

  In the first connection portion 24, the emission-side end F1a (output-side end surface) of the first transmission fiber F1 and the incident-side end Da (incident-side end surface) of the doped fiber D are fused together. A sleeve 41 made of cylindrical glass as a protective member (holding member) is extrapolated to the wearing portion across the first transmission fiber F1 side and the doped fiber D side. The sleeve 41 may be attached after the first transmission fiber F1 and the doped fiber D are fused, and the sleeve 41 is connected to the emission side end F1a of the first transmission fiber F1 and the doped fiber D. The incident side end portion Da may be inserted, and the emission side end portion F1a and the incident side end portion Da may be fused in the sleeve 41.

  The incident side end of the sleeve 41 is bonded to the first transmission fiber F1 with a first adhesive G1 (thermoplastic resin). The adhesive G1 is applied across the sleeve 41 and the first transmission fiber F1, and is applied over the entire circumference of the sleeve 41 and the first transmission fiber F1. Further, the output side end of the sleeve 41 is bonded to the doped fiber D with a second adhesive G2 (thermoplastic resin). The adhesive G2 is applied across the sleeve 41 and the doped fiber D, and is applied over the entire circumference of the sleeve 41 and the doped fiber D. In this way, since the sleeve 41 is bonded to the fibers F1 and D at both ends in the longitudinal direction, the distance from the fused portion at the ends of the fibers F1 and D to the bonded portions (adhesives G1 and G2) is increased. As a result, the influence of external force applied to the fibers F1 and D is hardly transmitted to the fused portion.

  Here, in the first connection portion 24, the excitation light is transmitted from the first transmission fiber F1 to the doped fiber D during the amplification of the light, and the rare earth element in the doped fiber D is excited. At this time, since the excitation light is only propagated in the first transmission fiber F1, the heat generation of the transmission fiber F1 during the propagation is extremely small. On the other hand, in the doped fiber D, since the rare earth element therein is easily excited by the excitation light, the amount of heat generated by the doped fiber D is larger than the amount of heat generated by the first transmission fiber F1. It has become.

  The longitudinal width T2 (width in the longitudinal direction of the fiber) of the second adhesive G2 used for the bonding portion between the doped fiber D and the sleeve 41 is the adhesion between the first transmission fiber F1 and the sleeve 41. It is set to be smaller than the longitudinal width T1 of the first adhesive G1 used for the portion. Accordingly, since the area where the fiber D and the sleeve 41 are covered with the adhesive G2 is reduced in the bonded portion between the doped fiber D and the sleeve 41, the heat generated in the doped fiber D in the bonded portion is not accumulated and is dissipated. It is easy to do.

  Further, the fixing strength of the sleeve 41 with respect to the first transmission fiber F1 and the doped fiber D (mainly the strength to withstand the longitudinal force) is mainly the longitudinal width T1 of the first and second adhesives G1 and G2. , T2 is determined by the total width. For this reason, it is possible to ensure the fixing strength of the sleeve 41 by setting the longitudinal width T1 of the first adhesive G1 to be larger by the amount that the longitudinal width T2 of the second adhesive G2 is set to be smaller. It has become. Moreover, it is preferable that the longitudinal width T2 of the second adhesive G2 is set to ½ or less of the longitudinal width T1 of the first adhesive G1.

  On the other hand, in the second connection portion 25, the emission side end portion Db (output side end surface) of the doped fiber D and the incident side end portion F2a (incident side end surface) of the second transmission fiber F2 are fused, A sleeve 42 made of cylindrical glass as a protective member (holding member) is extrapolated to the fused portion across the doped fiber D side and the second transmission fiber F2 side. The sleeve 42 is a member similar to the sleeve 41 of the first connection portion 24, and may be attached after the doped fiber D and the second transmission fiber F2 are fused. In addition, the emission side end Db of the doped fiber D and the incident side end F2a of the second transmission fiber F2 are inserted into the sleeve 42, and the emission side end Db and the incident side end F2a are connected to the sleeve. You may make it fuse | melt within 42.

  The incident side end of the sleeve 42 is bonded to the doped fiber D with a third adhesive G3 (thermoplastic resin). The adhesive G3 is applied across the sleeve 42 and the doped fiber D, and is applied over the entire circumference of the sleeve 42 and the doped fiber D. Further, the output side end of the sleeve 42 is bonded to the second transmission fiber F2 with a fourth adhesive G4 (thermoplastic resin). The adhesive G4 is applied across the sleeve 42 and the second transmission fiber F2, and is applied over the entire circumference of the sleeve 42 and the second transmission fiber F2. Thus, since the sleeve 42 is bonded to the fibers D and F2 at both ends in the longitudinal direction, the distance from the fused portion at the ends of the fibers D and F2 to the bonded portion (adhesives G3 and G4) is increased. As a result, the influence of the external force applied to the fibers D and F2 is hardly transmitted to the fused portion.

  Here, in the second connection portion 25, among the pumping light incident on the doped fiber D from the first transmission fiber F1, pumping light (residual pumping light) that has not been used for pumping in the doped fiber D is received. Then, the light enters from the emission side end Db of the doped fiber D to the second transmission fiber F2. At this time, due to the difference in propagation conditions between the doped fiber D and the second transmission fiber F2, the residual transmission light does not propagate well in the second transmission fiber F2, and heat is generated due to the influence of the residual excitation light. For this reason, the heat generation amount of the fiber F2 at the bonding portion between the second transmission fiber F2 and the sleeve 42 is larger than the heat generation amount of the fiber D at the bonding portion between the doped fiber D and the sleeve 42.

  The longitudinal width T4 of the fourth adhesive G4 used in the bonded portion between the second transmission fiber F2 and the sleeve 42 is the third width used in the bonded portion between the doped fiber D and the sleeve 42. It is set smaller than the longitudinal width T3 of the adhesive G3. As a result, since the area where the fiber F2 and the sleeve 42 are covered with the adhesive G4 is reduced in the bonded portion between the second transmission fiber F2 and the sleeve 42, the second transmission fiber F2 in the bonded portion is generated. It is easy to dissipate heat without accumulating heat.

  As in the case of the first connection portion 24, the fixing strength of the sleeve 42 with respect to the doped fiber D and the second transmission fiber F2 is mainly the longitudinal width T3 of the third and fourth adhesives G3 and G4. , T4. For this reason, it is possible to ensure the fixing strength of the sleeve 42 by setting the longitudinal width T3 of the third adhesive G3 large by the amount that the longitudinal width T4 of the fourth adhesive G4 is set small. It has become. In addition, the longitudinal width T4 of the fourth adhesive G4 is preferably set to ½ or less of the longitudinal width T3 of the third adhesive G3.

Next, the operation of the above embodiment will be described.
In the fiber protection structure of the present embodiment, in the first connection part 24 and the second connection part 25, the adhesive G2 (adhesive G4) of the adhesive part with the larger calorific value is replaced with the other adhesive G1 (adhesive G3). The width in the longitudinal direction is smaller than (), so that heat generated at the bonded portion where the amount of generated heat is large can be easily released. In addition, the longitudinal widths T1 and T3 of the adhesives G1 and G3 are increased by the amount corresponding to the reduction in the longitudinal widths T2 and T4 of the adhesives G2 and G4, and the total width of the adhesives G1 and G2 of the first connection portion 24 is increased. And, the fixing strength of the sleeves 41 and 42 is ensured by setting the total width of the adhesives G3 and G4 of the second connecting portion 25 to a size necessary for fixing.

Next, characteristic effects of the present embodiment will be described.
(1) In the first connecting portion 24, the fiber heat generation amount at the bonded portion between the doped fiber D and the sleeve 41 is larger than the fiber heat generation amount at the bonded portion between the first transmission fiber F1 and the sleeve 41. The longitudinal width T2 of the adhesive G2 on the doped fiber D side is set smaller than the longitudinal width T1 of the adhesive G1 on the first transmission fiber F1 side. Accordingly, since the area where the doped fiber D and the sleeve 41 are covered with the adhesive G2 is reduced in the bonded portion on the doped fiber D side, the heat generated in the bonded portion can be easily released. Thereby, it becomes possible to suppress the influence by the heat generation of the fiber at the bonded portion between the doped fiber D and the sleeve 41.

  Further, by increasing the longitudinal width T1 of the adhesive G1 on the first transmission fiber F1 side, the total width of the adhesives G1 and G2 can be set so as not to decrease, so the fixing strength of the sleeve 41 is ensured. can do. Thereby, it is possible to suppress the influence of the heat generation of the doped fiber D in the bonded portion while securing the fixing strength of the sleeve 41.

  On the other hand, in the second connection portion 25, the fiber heat generation amount at the bonded portion between the second transmission fiber F 2 and the sleeve 42 is larger than the fiber heat generation amount at the bonded portion between the doped fiber D and the sleeve 41. The longitudinal width T4 of the adhesive G4 on the second transmission fiber F2 side is set smaller than the longitudinal width T3 of the adhesive G3 on the doped fiber D side. Accordingly, since the area where the transmission fiber F2 and the sleeve 42 are covered with the adhesive G4 is reduced in the bonding portion on the second transmission fiber F2 side, the heat generated in the bonding portion can be easily released. . Thereby, it becomes possible to suppress the influence of the heat generation of the fiber at the bonded portion between the transmission fiber F2 and the sleeve 42.

  Further, since the total width of the adhesives G3 and G4 can be set not to decrease by increasing the longitudinal width T3 of the adhesive G3 on the doped fiber D side, the fixing strength of the sleeve 42 can be ensured. it can. As a result, it is possible to reduce the influence of heat generated by the transmission fiber F2 at the bonded portion while securing the fixing strength of the sleeve 42.

  Further, in the connection portions 24 and 25 between the doped fiber D and the transmission fibers F1 and F2 as described above, heat generation in the doped fiber D or the transmission fiber F2 tends to increase due to the power of optical amplification. For this reason, the heat dissipation effect by making longitudinal direction width T2, T4 of adhesive G2, G4 small can be made more effective.

  (2) Cylindrical sleeves 41 and 42 are used as the protective members of the first and second connecting portions 24 and 25, and the sleeves 41 and 42 are extrapolated so as to cover the fiber fusion portion. Thereby, since the fiber fusion | melting part is covered over the perimeter by the sleeves 41 and 42, the fusion | melting part can be protected more effectively.

  (3) Since the fibers D, F1, and F2 are made of quartz and the sleeves 41 and 42 are made of glass, the thermal expansion coefficients of the fibers D, F1, and F2 and the sleeves 41 and 42 are made close (to match). can do. For this reason, the influence of the thermal expansion of the fibers D, F1, F2 and the sleeves 41, 42 can be suppressed to a low level. For example, when the fibers D, F1, F2 and the sleeves 41, 42 are thermally expanded in the longitudinal direction due to the heat generation of the fibers D, F1, F2, the positions at the bonded portions of the fibers D, F1, F2 and the sleeves 41, 42 are as follows. Misalignment is unlikely to occur, thereby preventing the occurrence of poor adhesion.

  (4) The longitudinal direction width T2 of the adhesive G2 (the longitudinal direction width T4 of the adhesive G4) is set to ½ or less of the longitudinal direction width T1 of the adhesive G1 (the longitudinal direction width T3 of the adhesive G3). . Therefore, when the longitudinal width T2 of the adhesive G2 (longitudinal width T4 of the adhesive G4) is a small width suitable for heat dissipation, the longitudinal width T1 of the other adhesive G1 (the longitudinal direction of the adhesive G3) The width T3) is at least twice the longitudinal width of the longitudinal width T2 of the adhesive G2 (longitudinal width T4 of the adhesive G4). For this reason, the total width of the adhesives G1 and G2 (total width of the adhesives G3 and G4) can be increased, and the fixing strength of the sleeves 41 and 42 can be more suitably ensured.

  (5) The sleeve 41 (sleeve 42) is bonded to the fibers F1 and D (fibers D and F2) at both ends in the longitudinal direction. As a result, it is possible to secure a distance from the fused portion to the bonded portion of the fibers F1, D (fibers D, F2). As a result, the influence of external force applied to the fibers F1, D (fibers D, F2) is fused. It is possible to make it difficult to transmit to the wearing part.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the sleeves 41 and 42 made of glass are used as the protective member that protects the fused portion between the doped fiber D and the transmission fibers F1 and F2, but other than this, for example, the protective member is made of a metal material. A cylindrical sleeve may be used. According to this configuration, since the sleeve is made of a metal material having excellent heat dissipation, it is possible to efficiently release the heat generated in the fibers D, F1, and F2.

  Further, instead of the sleeves 41 and 42, a protective member 51 as shown in FIG. In addition, in FIG. 3, the example which changed the sleeve 41 of the 1st connection part 24 of the said embodiment into the protection member 51 is shown.

  The protection member 51 is made of a substantially rectangular parallelepiped metal member, and a V-shaped holding groove 51a along the longitudinal direction is formed on the upper surface thereof. In the holding groove 51a, the first transmission fiber F1 and the doped fiber D are arranged so as to come into contact with the V-shaped slopes, and the emission side end F1a of the first transmission fiber F1 and the doped fiber D are arranged. The incident side end Da is fused. In this state, adhesives G <b> 1 and G <b> 2 are applied from the upper side of the protective member 51 in order to bond the first transmission fiber F <b> 1 and the doped fiber D to the protective member 51, respectively. The longitudinal width T1 of the adhesive G1 is set smaller than the longitudinal width T2 of the adhesive G2.

  The operation and effect of the above embodiment can be obtained also by the configuration as shown in FIG. Further, in this configuration, since the protection member 51 is made of a metal material having excellent heat dissipation, it is possible to efficiently release the heat generated in the fibers D, F1, and F2. In addition, you may form the protection member 51 with glass other than a metal, for example. Also with this configuration, the same effect as the effect (3) of the above embodiment can be obtained.

  In the above embodiment, the fibers D, F1, and F2 are quartz fibers, but other than this, for example, glass fibers may be used. Also with this configuration, the same effect as the effect (3) of the above embodiment can be obtained.

In the above embodiment, only one optical amplifying unit (doped fiber D) is provided, but the present invention is not particularly limited to this, and two or more optical amplifying units may be provided.
-In the said embodiment, although the thermoplastic resin was used for the adhesive agents G1-G4, it is not specifically limited to this, For example, you may use a thermosetting resin.

  In the above embodiment, the present invention is applied to the protective structure in the connection portions 24 and 25 between the doped fiber D and the transmission fibers F1 and F2 in the laser processing apparatus 10, but other than this, for example, fiber connection in an optical communication apparatus You may apply to the protection structure of a part.

  DESCRIPTION OF SYMBOLS 10 ... Laser processing apparatus, 21 ... Seed light source, 23 ... Excitation light source, 41, 42 ... Sleeve (protective member), 51 ... Protective member, D ... Dope fiber, Da ... End side of doped fiber, Db ... Dope fiber F1 ... first transmission fiber, F1a ... first transmission fiber exit side end, F2 ... second transmission fiber, F2a ... second transmission fiber entrance side end, G1- G4: First to fourth adhesives, T1 to T4: Longitudinal widths of the first to fourth adhesives.

Claims (10)

A fiber protection structure in which ends of a pair of fibers are fused together, and a protective member that is attached to the fused portion and protects the fused portion is bonded to the pair of fibers with an adhesive,
The fiber heat generation amount at the bonding portion between one of the fibers and the protection member is larger than the fiber heat generation amount at the bonding portion between the other fiber and the protection member, and is used for the bonding portion having the larger fiber heat generation amount. The fiber protection structure according to claim 1, wherein a longitudinal width of the adhesive is set smaller than a longitudinal width of the adhesive used for the other adhesive portion. The fiber protection structure according to claim 1,
The pair of fibers includes a doped fiber for optical amplification containing a rare earth element therein and a transmission fiber for transmitting light. The fiber protection structure according to claim 1 or 2,
The fiber protection structure, wherein the protection member is a cylindrical sleeve and is extrapolated so as to cover a fusion portion between the ends of the pair of fibers. In the fiber protection structure according to any one of claims 1 to 3,
The pair of fibers are made of quartz or glass,
The fiber protection structure, wherein the protection member is made of glass. In the fiber protection structure according to any one of claims 1 to 3,
The said protection member consists of metal materials, The fiber protection structure characterized by the above-mentioned. In the fiber protection structure according to any one of claims 1 to 5,
The longitudinal width of the adhesive used for the adhesive portion having the larger fiber heat generation amount is set to ½ or less of the longitudinal width of the adhesive used for the other adhesive portion. A fiber protection structure characterized by End portions of a transmission fiber and a doped fiber for optical amplification containing a rare earth element are fused together, a protective member attached to the fused portion to protect the fused portion, the transmission fiber, and the dope A laser processing apparatus having a fiber protection structure in which fibers are bonded with an adhesive,
Of the transmission fiber and the doped fiber, a fiber heat generation amount at a bonded portion between one fiber and the protective member is larger than a fiber heat generation amount at a bonded portion between the other fiber and the protective member. The laser processing apparatus characterized in that the longitudinal width of the adhesive used for the larger adhesive portion is set smaller than the longitudinal width of the adhesive used for the other adhesive portion. . In the laser processing apparatus of Claim 7,
The transmission fiber is connected to the incident side end of the doped fiber, and transmits the signal laser light from the seed light source and the excitation light from the excitation light source to the doped fiber,
The fiber heat generation amount at the bonded portion between the doped fiber and the protective member is larger than the fiber heat generation amount at the bonded portion between the transmission fiber and the protective member, and the longitudinal width of the adhesive on the doped fiber side is The laser processing apparatus is set to be smaller than the longitudinal width of the adhesive on the transmission fiber side. In the laser processing apparatus of Claim 7,
The transmission fiber is connected to an output side end of the doped fiber, and introduces laser light amplified by the doped fiber.
The fiber heat generation amount at the bonded portion between the transmission fiber and the protective member is larger than the fiber heat generation amount at the bonded portion between the doped fiber and the protective member, and the longitudinal width of the adhesive on the transmission fiber side. Is set to be smaller than the longitudinal width of the adhesive on the doped fiber side. A fiber protection method in which ends of a pair of fibers are fused together, a protective member is attached to the fused portion, and the protective member and the pair of fibers are bonded with an adhesive, respectively.
The fiber heat generation amount in the bonded portion between one of the fibers and the protective member is larger than the fiber heat generation amount in the bonded portion between the other fiber and the protective member, and the bonded portion of the bonded portion having the larger fiber heat generation amount A fiber protection method, wherein the longitudinal width of the adhesive is set smaller than the longitudinal width of the adhesive at the other adhesive portion.

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