JP6767446B2 - Fiber optic assembly, optical cable, and laser system - Google Patents

Description

The present invention relates to an optical fiber assembly with an optical fiber and an optical cable and laser system with such an optical fiber assembly.

In an optical fiber that propagates high-power laser light, it is required that the output of the laser light can be quickly reduced when the optical fiber is damaged for some reason. Therefore, Patent Document 1 and Patent Document 2 describe techniques for detecting that the optical fiber has been damaged.

FIG. 2 of Patent Document 1 accommodates an optical fiber, a first detection line wound around the outer surface of the optical fiber, and a second detection line arranged along the optical fiber. A laser guide with a protective tube and is described. The first detection line and the second detection line are obtained by replacing the conductive lines described in Patent Document 1. Further, FIGS. 1 and 2 of Patent Document 2 include an optical fiber, a first detection line and a second detection line, an inner tube for accommodating these, and an outer tube for accommodating the inner tube. A fiber cable for laser light transmission is described. The first detection line and the second detection line are obtained by replacing the first disconnection detection line and the second disconnection detection line described in Patent Document 2.

In these laser guide and laser light transmission fiber cables, one end of the first detection line and the second detection line are connected so as to be conductive, so that between the other ends. The resistance value in can be monitored.

If the optical fiber is undamaged, the resistance value does not change. On the other hand, when the optical fiber is damaged in some way, the power of the laser beam leaked from the optical fiber melts at least one of the first detection line and the second detection line and breaks the wire. Become infinite.

In these laser guides and fiber cables for laser light transmission, it is possible to detect that the optical fiber has been damaged by detecting the change in the resistance value.

Japanese Unexamined Patent Publication No. 2003-279444 Japanese Unexamined Patent Publication No. 2014-224898

However, in the laser guide described in FIG. 2 of Patent Document 1, when the optical fiber and the protective tube are bent, stress is concentrated at the intersection of the first detection line and the second detection line. There is a problem that it is easy. Since this stress causes a pressure acting on the side surface of the optical fiber (that is, lateral pressure), it causes a transmission loss of the optical fiber due to the lateral pressure.

Further, in the fiber cable for laser optical transmission described in FIGS. 1 and 2 of Patent Document 2, the optical fiber and the first detection line are remarkably separated in the inner tube, so that the optical fiber is damaged. There is a problem that a time lag occurs between the received timing and the timing at which the first detection line is disconnected. That is, this fiber cable for laser optical transmission has a problem that it cannot quickly detect that the optical fiber has been damaged.

One aspect of the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to quickly detect damage to an optical fiber while reducing transmission loss due to lateral pressure of the optical fiber. Is to provide the technology that can be done.

In order to solve the above problems, the optical fiber assembly according to one aspect of the present invention includes an optical fiber, one or more detection lines arranged along the outer surface of the optical fiber, and one or more tear cords. In at least a part of the optical fiber, one or a plurality of detection lines and one or a plurality of tear cords, each of which is spirally wound without intersecting with each other, and the above-mentioned at least a part of the section. It includes one or more detection lines, the one or more tear cords, and a first resin layer covering the outer surface.

In an optical fiber assembly configured in this way, each of one or more detection lines and one or more tear cords spirals along the outer surface of the optical fiber in at least a portion of the fiber optic without intersecting each other. It is wrapped in a shape. Therefore, this optical fiber assembly can prevent the detection lines from intersecting with each other, the detection lines from intersecting with the tear cord, and the tear cords from intersecting with each other. Therefore, this optical fiber assembly can reduce the transmission loss due to the lateral pressure of the optical fiber even when the optical fiber is bent.

Further, in the optical fiber assembly configured as described above, since one or a plurality of detection lines are wound along the outer surface of the optical fiber in at least a part section of the optical fiber, one or a plurality of detection lines are wound with the optical fiber. It is possible to prevent the detection line from being separated from the detection line. Therefore, this optical fiber assembly can quickly detect that the optical fiber has been damaged.

As described above, this optical fiber assembly can quickly detect that the optical fiber has been damaged while reducing the transmission loss due to the lateral pressure of the optical fiber.

Further, in the optical fiber assembly according to one aspect of the present invention, it is preferable that the one or more detection lines are a plurality of detection lines.

According to the above configuration, an optical fiber assembly having a single detection line is provided on the outer surface of the optical fiber as compared with an optical fiber assembly having a detection line pitch equal to that of the main optical fiber assembly. The density of the detection line wound along the outer surface can be increased. Therefore, it is possible to detect that the optical fiber has been damaged more quickly.

Further, in the optical fiber assembly according to one aspect of the present invention, two detection lines out of the plurality of detection lines are used as the first detection line and the second detection line, and the first detection line and the second detection line are used. It is preferable that one end of the detection line of the above is conducting with the thermistor.

According to the above configuration, the resistance value between the other ends of the first detection line and the second detection line, which is near the thermistor by monitoring the resistance value including the resistance value of the thermistor. The temperature can be monitored. For example, if an optical fiber assembly is used as a delivery fiber in a laser system for machining, the thermistor can be placed inside the output head of the laser system to monitor the temperature inside the output head. it can. As described above, this optical fiber assembly can detect that the optical fiber has been damaged and can also monitor the temperature in the vicinity of the thermistor.

Further, in the optical fiber assembly according to one aspect of the present invention, it is preferable that the first resin layer is provided over one pitch or more of all the sections of the optical fiber.

Since the resin layer covers one or more detection lines, one or more tear cords, and the outer surface of the optical fiber, one or more detection lines and one or more tear cords are applied to the outer surface. Can be brought into close contact with each other. In this optical fiber assembly, since such a resin layer is provided over a section of one pitch or more in the entire section of the optical fiber, one or a plurality of detection lines and one or a plurality of tear strings are respectively provided. It can be more firmly fixed to the outer surface. Therefore, for example, when the optical fiber assembly is inserted into a tube accommodating the optical fiber assembly, the optical fiber assembly can improve workability.

Further, in the optical fiber assembly according to one aspect of the present invention, the optical fiber includes a bare fiber and a second resin layer covering the bare fiber, and constitutes a surface layer of the second resin layer. The melting point of the resin is preferably higher than the melting point of the resin constituting the first resin layer.

As a manufacturing method for manufacturing this optical fiber assembly, for example, (1) a step of drawing a bare fiber, (2) a step of forming a second resin layer, and (3) one or more detection lines and 1 Alternatively, a manufacturing method including a step of winding a plurality of tear strings around the outer surface (surface of the second resin layer) of the optical fiber and (4) a step of forming the first resin layer can be considered.

According to the above configuration, since the melting point of the resin constituting the surface layer of the second resin layer is higher than the melting point of the resin constituting the first resin layer, in the step of forming the first resin layer, the first It is possible to prevent the resin layer from fusing to the second resin layer. As a result, this optical fiber assembly can easily remove the first resin layer when only the first resin layer is removed.

In order to solve the above problems, the optical cable according to one aspect of the present invention includes an optical fiber assembly according to any one aspect of the present invention and one or a plurality of tubes accommodating the optical fiber assembly. There is.

In order to solve the above problems, the laser system according to one aspect of the present invention is a laser unit optically coupled to the optical cable according to any one aspect of the present invention and one end of the optical cable. And an output head that is optically coupled to the other end of the optical cable.

The above-mentioned optical cable and laser system have the same effect as the optical fiber assembly according to any one aspect of the present invention.

According to one aspect of the present invention, it is possible to provide a technique capable of quickly detecting damage to an optical fiber while reducing transmission loss due to lateral pressure of the optical fiber.

(A) is a perspective view of a part of an optical fiber assembly according to the first embodiment of the present invention. (B) is a cross-sectional view of the optical fiber assembly shown in (a). It is a perspective view of the removal section of the optical fiber assembly shown in FIG. 1, (a) shows the removal section in the state where the tear string is unwound, and (b) is the removal in the state where two detection lines are unwound. The section is shown, and (c) shows the removal section in the state where the thermistor is connected to the two detection lines. It is sectional drawing of the optical cable which concerns on 2nd Embodiment of this invention. It is a block diagram of the fiber laser system which concerns on 3rd Embodiment of this invention. It is a block diagram of the fiber laser apparatus which concerns on 4th Embodiment of this invention.

[First Embodiment]
The optical fiber assembly 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1A is a perspective view of a part of the optical fiber assembly 10. FIG. 1B is a cross-sectional view of the optical fiber assembly 10. FIG. 2 is a perspective view of the removal section 10a of the optical fiber assembly 10. More specifically, FIG. 2A shows a removal section 10a in a state where the tear string 13 is unwound, and FIG. 2B shows a removal section 10a in a state where the detection lines 12a and 12b are unwound. FIG. 2C shows a removal section 10a in a state where the thermistor 15 is connected to the detection lines 12a and 12b.

The length of the optical fiber assembly 10 is not particularly limited, but in an example of a long one, it reaches several hundred meters to several kilometers. An optical cable 100 (see FIG. 2) is constructed after cutting out a length suitable for the application from the long optical fiber assembly 10 in this way, and the laser unit LU is optically coupled to one end. The laser system LS (see FIG. 3) can be constructed by optically coupling the output head OH to the other end. Each of the optical cable 100 and the laser system LS will be described later with reference to FIGS. 2 and 3, respectively.

As shown in FIG. 1, the optical fiber assembly 10 includes an optical fiber core wire 11, a detection wire 12a, a detection wire 12b, a tear cord 13, and a resin layer 14.

(Optical fiber core wire 11)
The optical fiber core wire 11 is composed of a bare fiber 11a and a resin layer 11b. Each of the optical fiber core wire 11 and the resin layer 11b is an example of the optical fiber and the second resin layer described in the claims, respectively. In FIG. 1, the core and clad included in the bare fiber 11a are not shown. As the bare fiber 11a, any form of optical fiber can be adopted. For example, focusing on the number of clad layers, the bare fiber 11a may be a single clad fiber, a double clad fiber, or a triple clad fiber. For example, paying attention to the number of modes of light propagated by the bare fiber 11a, the bare fiber 11a may be a single mode fiber or a multimode fiber including a fumode fiber.

In the present embodiment, the resin layer 11b is composed of an inner layer 11b1 and an outer layer 11b2. The inner layer 11b1 functions as a buffer layer for buffering an external force applied to the bare fiber 11a from the outside. As the resin constituting the inner layer 11b1, a resin having high elasticity (for example, a silicone resin or an ultraviolet curable resin) is suitable. The outer layer 11b2 functions as a protective layer for preventing the bare fiber 11a from being damaged by an external force applied to the bare fiber 11a. As the resin constituting the outer layer 11b2, a resin having high hardness (for example, polyamide resin or polyester resin) is suitable.

The structure of the resin layer 11b is not limited to the above-mentioned structure, and can be appropriately selected. For example, the resin layer 11b may be composed of one resin layer, may be composed of two resin layers as shown in FIG. 1, or may be composed of three or more resin layers. May be.

(Detection lines 12a, 12b and tear string 13)
Each of the detection lines 12a and 12b is an example of one or more detection lines described in the claims. In the present embodiment, it is assumed that the detection line 12a is the first detection line and the detection line 12b is the second detection line. In the present embodiment, each of the detection lines 12a and 12b is made of metal (made of copper in this embodiment). However, the metal constituting the detection lines 12a and 12b is not limited to copper and can be appropriately selected. Further, the surfaces of the detection lines 12a and 12b may be covered with a resin layer.

The tear string 13 is an example of one or more tear strings described in the claims. In the present embodiment, the tear cord 13 is preferably made of fibers having high tensile strength. Examples of fibers having high tensile strength include aramid fibers, carbon fibers, and glass fibers.

Each of the detection lines 12a and 12b and the tear cord 13 spirals along the outer surface (surface of the resin layer 11b) of the optical fiber core wire 11 and does not intersect with each other. Wrapped around. That is, each of the detection lines 12a and 12b and the tear string 13 travels in the traveling direction (for example, from the left side to the right side of the perspective view shown in FIG. 1A) in the direction along the central axis of the optical fiber core wire 11. As a direction), it is wound around the optical fiber core wire 11 so as to rotate clockwise as it advances in the traveling direction.

As shown in FIG. 1A, the length of the section along the traveling direction is such that the detection lines 12a and 12b and the tear string 13 each rotate 360 ° around the central axis of the optical fiber core wire 11. The length of the section required for this is called one pitch.

It is preferable that the pitch of the detection line 12a, the pitch of the detection line 12b, and the pitch of the tear string 13 are uniform over the entire section around which the optical fiber core wire 11 is wound.

Further, each of the pitch of the detection line 12a, the pitch of the detection line 12b, and the pitch of the tear string 13 is preferably equal to the average of all the sections of the optical fiber core wire 11, and all the sections of the optical fiber core wire 11 are equal to each other. It is more preferable that they are equal over.

Further, when the optical fiber core wire 11 is viewed in a plan view from the side, it is preferable that the detection wires 12a and 12b and the tear cord 13 are arranged at equal intervals. Specifically, in the perspective view shown in FIG. 1A, the distance between the tear string 13 and the detection line 12a, the distance between the detection line 12a and the detection line 12b, and the distance between the detection line 12a and the next turn The distance from the tear string 13 is preferably equal.

According to these configurations, it is possible to prevent any two of the pitch of the detection line 12a, the pitch of the detection line 12b, and the pitch of the tear string 13 from intersecting with each other in the entire section of the optical fiber assembly 10. Therefore, even when the optical fiber assembly 10 is bent, it is possible to prevent stress from concentrating on any part of the side surface of the optical fiber core wire 11.

(Resin layer 14)
As shown in FIGS. 1A and 1B, in at least a part of the bare fiber 11a, the resin layer 14 includes the detection lines 12a and 12b, the tear cord 13, and the outer surface of the optical fiber core wire 11. And is covered. The resin layer 14 is an example of the first resin layer described in the claims.

The resin layer 14 has a function of adhering the detection wires 12a and 12b and the tear cord 13 to the outer surface of the optical fiber core wire 11.

In the optical fiber assembly 10, the resin layer 14 is preferably provided over a section of one pitch or more in the entire section of the optical fiber core wire 11. Further, in the optical fiber assembly 10 in a state before both ends are coupled to the laser unit LU and the output head OH, which will be described later, the resin layer 14 is provided over the entire section of the optical fiber core wire 11. Is preferable.

The material constituting the resin layer 14 is not particularly limited and may be appropriately selected. However, as will be described later with reference to FIG. 2, the resin layer 14 is removed from the outer surface of the optical fiber core wire 11 by unwinding the tear string 13, in other words, the detection lines 12a and 12b are removed from the optical fiber. When it is assumed that the core wire 11 is separated from the outer surface, the melting point of the resin constituting the surface layer (outer layer 11b2 in the present embodiment) of the resin layer 11b is the melting point of the resin constituting the resin layer 14. Higher is preferable.

As an example of such a configuration, a polyester resin having a melting point of 230 ° C. is used as the resin constituting the outer layer 11b2, and a polyamide resin having a melting point of 190 ° C. is used as the resin constituting the resin layer 14. Can be mentioned.

(Thermistor 15)
As described above, in the optical fiber assembly 10, it is preferable to use a tear cord 13 made of fibers having high tensile strength. In this case, as shown in FIG. 2A, the tear cord 13 can be unwound from the optical fiber core wire 11 by pulling the tear cord 13 in any part of the section. In the example shown in FIG. 2A, the optical fiber core wire 11 is unwound from one end of the optical fiber assembly 10 over a section for about two turns. In the following, the section in which the optical fiber core wire 11 shown in FIG. 2A is unwound is referred to as a removal section 10a.

Since the unwound portion of the tear string 13 is an obstacle, it is preferable to cut it appropriately. In this embodiment, the tear string 13 is cut at the position of the AA'line shown in FIG. 2A.

In the removal section 10a, the resin layer 14 is formed with a spiral fracture region by unwinding the tear string 13. The virtual line (dashed line) shown in FIG. 2A indicates the position where the tear string 13 before unwinding was wound.

With this fracture region as a trigger, the resin layer 14 provided in the removal section 10a can be removed from the outer surface of the optical fiber core wire 11. In particular, when a resin having a melting point higher than the melting point of the resin constituting the resin layer 14 is used as the resin constituting the surface layer (outer layer 11b2 in the present embodiment) of the resin layer 11b, the resin layer 14 Is capable of appropriately suppressing the force of the resin layer 11b to bond to the surface layer, so that the resin layer 14 provided in the removal section 10a can be easily removed from the outer surface of the optical fiber core wire 11.

As a result, as shown in FIG. 2B, the detection lines 12a and 12b wound around the removal section 10a can be unwound from the optical fiber core wire 11. The virtual line shown in FIG. 2B indicates the position where the detection lines 12a and 12b before unwinding were wound.

Each terminal of the thermistor 15 is connected to each of the ends of the detection wires 12a and 12b separated from the outer surface of the optical fiber core wire 11 by being unwound from the optical fiber core wire 11 (solder in this embodiment). (See (c) in FIG. 3). That is, in the optical fiber assembly 10 shown in FIG. 3 (c), one end of the detection lines 12a and 12b is electrically connected to each other via the thermistor 15.

(Effect of optical fiber assembly 10)
The optical fiber assembly 10 is an optical fiber core wire 11, detection lines 12a and 12b arranged along the outer surface of the optical fiber core wire 11, and a tear cord 13, and is at least a part of the optical fiber core wire 11. In the above, the detection lines 12a and 12b and the tear string 13 which are spirally wound around each other without intersecting each other, and the resin layer 14 which covers the detection lines 12a and 12b and the tear string 13 in at least a part of the above sections. And have.

In the optical fiber assembly 10, each of the detection wires 12a and 12b and the tear cord 13 is spirally wound along the outer surface of the optical fiber core wire 11 without intersecting with each other. Therefore, the optical fiber assembly 10 can prevent the detection lines 12a and 12b from intersecting with each other and the tear string 13 from intersecting with any of the detection lines 12a and 12b. Further, when the optical fiber assembly 10 includes a plurality of tear cords, it is possible to prevent the tear cords from crossing each other. Therefore, the optical fiber assembly 10 can reduce the transmission loss due to the lateral pressure of the optical fiber core wire 11 even when the optical fiber core wire 11 is bent.

Further, in the optical fiber assembly 10, since the detection lines 12a and 12b are wound along the outer surface of the optical fiber core wire 11, the optical fiber core wire 11 and the detection lines 12a and 12b are significantly separated from each other. Can be prevented. Therefore, the optical fiber assembly 10 can quickly detect that the optical fiber core wire 11 has been damaged.

As described above, the optical fiber assembly 10 can quickly detect that the optical fiber core wire 11 has been damaged while reducing the transmission loss due to the lateral pressure of the optical fiber core wire 11.

In the present embodiment, the optical fiber core wire 11 has been adopted as an example of the optical fiber described in the claims. However, as an example of the optical fiber described in the claims, a bare fiber 11a in which the resin layer 11b is omitted can also be adopted.

Further, in the optical fiber assembly 10, the one or more detection lines described in the claims are preferably a plurality of detection lines (two detection lines 12a and 12b in the present embodiment).

According to the above configuration, the optical fiber core wire 11 is compared with the optical fiber assembly having a single detection line and having the same detection line pitch as the optical fiber assembly 10. The density of the detection line wound along the outer surface on the outer surface can be increased. Therefore, it is possible to more quickly detect that the optical fiber core wire 11 has been damaged.

Further, in the optical fiber assembly 10, two of the plurality of detection lines are the first detection line (detection line 12a shown in FIG. 1) and the second detection line (detection line shown in FIG. 1). As 12b), it is preferable that one end of the first detection line and the second detection line are electrically connected to each other via the thermistor 15.

According to the above configuration, the resistance value between the other ends of the first detection line and the second detection line, which is near the thermistor by monitoring the resistance value including the resistance value of the thermistor. The temperature can be monitored. For example, when the optical fiber assembly 10 is adopted as the delivery fiber provided in the laser system LS for processing, the thermistor 15 is arranged in the output head OH of the laser system LS, so that the inside of the output head OH The temperature can be monitored. As described above, the optical fiber assembly 10 can detect that the optical fiber core wire 11 has been damaged, and can also monitor the temperature in the vicinity of the thermistor 15.

Further, in the optical fiber assembly 10, it is preferable that the resin layer 14 is provided over one pitch or more of all the sections of the optical fiber core wire 11.

Since the resin layer 14 covers the outer surfaces of the detection wires 12a and 12b, the tear cord 13, and the optical fiber core wire 11, the detection wires 12a and 12b and the tear cord 13 should be brought into close contact with the outer surface. Can be done. In the optical fiber assembly 10, since such a resin layer 14 is provided over a section of one pitch or more in the entire section of the optical fiber core wire 11, each of the detection lines 12a and 12b and the tear string 13 is provided. It can be fixed to the outer surface with sufficient strength. Therefore, for example, when the optical fiber assembly 10 is inserted into a tube (see FIG. 3) that houses the optical fiber assembly 10, the optical fiber assembly 10 can improve workability.

Further, in the optical fiber assembly 10, the optical fiber core wire 11 includes a bare fiber 11a and a resin layer 11b covering the bare fiber 11a, and the melting point of the resin constituting the surface layer of the resin layer 11b is the resin layer 14. It is preferably higher than the melting point of the resin constituting the above.

Examples of the manufacturing method for manufacturing the optical fiber assembly 10 include (1) a step of drawing a bare fiber 11a, (2) a step of forming a resin layer 11b, and (3) detection lines 12a and 12b and a tear string 13. A manufacturing method including a step of winding the optical fiber core wire 11 around the outer surface (surface of the resin layer 11b) and (4) a step of forming the resin layer 14 can be considered.

According to the above configuration, since the melting point of the resin constituting the surface layer of the resin layer 11b is higher than the melting point of the resin constituting the resin layer 14, the resin layer 14 is melted into the resin layer 11b in the step of forming the resin layer 14. You can prevent it from being worn. As a result, the optical fiber assembly 10 can easily remove the resin layer 14 when only the resin layer 14 is removed from the outer surface of the optical fiber core wire 11.

[Second Embodiment]
The optical cable 100 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of the optical cable 100. The description of the optical fiber assembly 10 (see FIGS. 1 and 2) described in the first embodiment will be omitted in the present embodiment.

As shown in FIG. 3, the optical cable 100 includes an optical fiber assembly 10, an inner tube 20, and an outer tube 30.

The inner tube 20 accommodates the optical fiber assembly 10. In the present embodiment, the inner tube 20 is composed of a resin tube made of resin (made of tetrafluoroethylene resin in this embodiment) and a braided wire formed by knitting a conducting wire (for example, a copper wire). ..

The optical fiber assembly 10 wound on the roll at the time of manufacturing is cut out to a length suitable for the intended use and then inserted into the inner tube 20.

The outer tube 30 includes a bellows 31 and a protective layer 32. The bellows 31 is a metal tube (stainless steel in this embodiment), and the side wall is formed into a bellows shape. The protective layer 32 is a resin layer coated on the outer surface of the bellows 31. The outer tube 30 accommodates the optical fiber assembly 10 and the inner tube 20.

The optical cable 100 has the same effect as the optical fiber assembly 10. Further, since the optical cable 100 includes the inner tube 20 and the outer tube 30, it is possible to protect the optical fiber assembly 10 from various impacts that can be received from the outside.

In the present embodiment, the optical cable 100 has been described as including the inner tube 20 and the outer tube 30. However, in the optical cable 100, either the inner tube 20 or the outer tube 30 can be omitted as appropriate depending on the required impact resistance, ease of handling, and the like, and the inner tube 20 and the outer tube 20 can be omitted. In addition to 30, additional tubes can be added.

[Third Embodiment]
The fiber laser system FLS according to the third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram of the fiber laser system FLS.

The fiber laser system FLS employs the optical cable 100 described in the second embodiment as the output delivery fiber ODF. The description of the optical fiber assembly 10 (see FIGS. 1 and 2) described in the first embodiment and the description of the optical cable 100 (see FIG. 3) described in the second embodiment are described in the present embodiment. Omit. The fiber laser system FLS is an example of the laser system described in the claims.

Further, the expression “connection” used in the present embodiment means that the two members are optically connected.

The fiber laser system FLS is a laser device for processing a work W, which is an object to be processed. As shown in FIG. 4, n fiber laser units FLU1 to FLUN, n laser delivery fibers LDF1 to LDFn, It includes an output combiner OC, an output delivery fiber ODF, and an output head OH. The fiber laser units FLU1 to FLUN and the laser delivery fibers LDF1 to LDFn have a one-to-one correspondence with each other. Here, n is an arbitrary natural number of 1 or more, and represents the number of the fiber laser units FLU1 to FLUN and the laser delivery fibers LDF1 to LDFn. Note that FIG. 4 shows a configuration example of the fiber laser system FLS when n = 7. Further, the output combiner OC is one aspect of the combiner described in the claims, and includes n input ports and one output port. The output combiner OC combines n laser beams input to each input port into one laser beam, and outputs the combined laser beam from the output port.

The fiber laser unit FLUi (i is a natural number of 1 or more and n or less) generates a laser beam. In this embodiment, a forward-excited fiber laser is used as the fiber laser units FLU1 to FLUN. The fiber laser unit FLUi is connected to the input end of the corresponding laser delivery fiber LDFi. The laser light generated by the fiber laser unit FLUi is input to the laser delivery fiber LDFi.

The laser delivery fiber LDFi guides the laser light generated by the corresponding fiber laser unit FLUi. The laser delivery fibers LDF1 to LDFn may be single-mode fibers or fumode fibers having 10 or less modes.

In this embodiment, the fumode fiber is used as the laser delivery fibers LDF1 to LDFn. The output end of the laser delivery fiber LDFi is connected to the input port of the output combiner OC. The laser light generated by the fiber laser unit FLUi and guided through the laser delivery fiber LDFi is input to the output combiner OC via this input port.

The output combiner OC combines the laser light generated by each of the fiber laser units FLU1 to FLUN and guided through each of the laser delivery fibers LDF1 to LDFn. The output port of the output combiner OC is connected to the input end of the output delivery fiber ODF. The laser beam combined with the output combiner OC is input to this output delivery fiber ODF. That is, the incident surface of the output delivery fiber ODF is coupled to the plurality of fiber laser units FLUi via the output combiner OC.

The output delivery fiber ODF guides the laser beam combined with the output combiner OC. In this embodiment, a multimode fiber is used as an output delivery fiber ODF. The output end of the output delivery fiber ODF (the end of the optical fiber core wire 11 shown in FIG. 2C) is connected to the output head OH. Further, the thermistor (thermistor 15 shown in FIG. 2C) provided at the end of the output delivery fiber ODF is fixed to the housing of the output head OH. According to this configuration, the fiber laser system FLS is a resistance value between the ends of the two detection lines (detection lines 12a and 12b shown in FIG. 2C) opposite to the thermistor. By monitoring the resistance value including the resistance value of the thermistor, the temperature of the housing of the output head OH can be monitored.

Further, a spatial optical system (for example, a convex lens, not shown in FIG. 4) for focusing the laser beam emitted from the output head OH on the surface of the work W is provided between the output head OH and the work W. ing. The laser beam combined with the output combiner OC is emitted from the output head OH and is irradiated to the work W in a state focused by the spatial optical system.

In this embodiment, the output combiner OC is adopted as an example of the combine unit described in the claims. However, in one aspect of the present invention, a spatial optical system including a plurality of convex lenses can be adopted as an example of the wave junction described in the claims. When this spatial optical system is composed of n convex lenses, each convex lens focuses the laser light emitted from the laser delivery fiber LDFi of each fiber laser unit FLUi, and outputs each focused laser light. It may be arranged so as to be coupled to the core of the delivery fiber ODF.

(Structure of fiber laser unit)
The configuration of the fiber laser unit FLU1 included in the fiber laser system FLS will be described with reference to FIG. The fiber laser units FLU2 to FLUN are also configured in the same manner as the fiber laser unit FLU1.

The fiber laser unit FLU1 is a forward-pumped fiber laser, and as shown in FIG. 4, m excitation light sources PS1 to PSm, m excitation delivery fibers PDF1 to PDFm, an excitation combiner PC, and a high-reflection fiber Bragg. It includes a grating FBG-HR, an amplification fiber AF, and a low reflection fiber Bragg grating FBG-LR. That is, the fiber laser unit FLU1 is a resonator type fiber laser unit. The excitation light sources PS1 to PSm and the excitation delivery fibers PDF1 to PDFm have a one-to-one correspondence with each other. Here, m is an arbitrary natural number of 2 or more, and represents the number of excitation light sources PS1 to PSm and excitation delivery fibers PDF1 to PDFm. Note that FIG. 4 shows a configuration example of the fiber laser unit FLU1 when m = 6.

The excitation light source PSj (j is a natural number of 1 or more and m or less) generates excitation light. In this embodiment, the laser diode is used as the excitation light source PS1 to PSm. The excitation light source PSj is connected to the input end of the corresponding excitation delivery fiber PDFj. The excitation light generated by the excitation light source PSj is input to the excitation delivery fiber PDFi.

The excitation delivery fiber PDFj waveguides the excitation light generated by the corresponding excitation light source PSj. The output end of the excitation delivery fiber PDFj is connected to the input port of the excitation combiner PC. The excitation light generated by the excitation light source PSj and guided through the excitation delivery fiber PDFj is input to the excitation combiner PC via this input port.

The excitation combiner PC is generated by each of the excitation light sources PS1 to PSm, and the excitation light guided through each of the excitation delivery fibers PDF1 to PDFm is combined. The output port of the excitation combiner PC is connected to the input end of the amplification fiber AF via a high reflection fiber Bragg grating FBG-HR. Of the excitation light combined by the excitation combiner PC, the excitation light transmitted through the highly reflective fiber Bragg grating FBG-HR is input to the amplification fiber AF.

The amplification fiber AF uses the excitation light transmitted through the highly reflective fiber Bragg grating FBG-HR to generate laser light. In the present embodiment, a double clad fiber in which a rare earth element (for example, Yb) is added to the core (Raman gain coefficient = 1 × ^10-13 [
1 / W]) is used as the amplification fiber AF. The excitation light transmitted through the highly reflective fiber Bragg grating FBG-HR is used to maintain this rare earth element in a population inversion. The output end of the amplification fiber AF is connected to the input end of the laser delivery fiber LDF1 via a low reflection fiber Bragg grating FBG-LR. The high-reflection fiber Bragg grating FBG-HR functions as a mirror at a certain wavelength λ (for example, 1060 nm) (reflectance is, for example, 99%), and the low-reflection fiber Bragg grating FBG-LR acts as a half mirror at that wavelength λ. It works (reflectance is, for example, 10%). Therefore, the amplification fiber AF, together with the high-reflection fiber Bragg grating FBG-HR and the low-reflection fiber Bragg grating FBG-LR, constitutes a resonator that oscillates a laser beam having a wavelength of λ. Of the laser light generated by the amplification fiber AF, the laser light transmitted through the low reflection fiber Bragg grating FBG-LR is input to the laser delivery fiber LDF1.

In the present embodiment, the forward-excited fiber laser is used as the fiber laser units FLU1 to FLUN, but the present invention is not limited to this. That is, in the present invention, the backward excitation type fiber laser can be used as the fiber laser units FLU1 to FLUN, or the bidirectional excitation type fiber laser can be used as the fiber laser units FLU1 to FLUN.

The fiber laser system FLS configured in this way has the same effect as the optical fiber assembly 10.

In the present embodiment, the fiber laser system FLS employs a resonator type fiber laser unit as the fiber laser units FLU1 to FLUn, which are the laser units described in the claims. However, in the fiber laser system FLS, a MOPA type fiber laser unit can also be adopted as each fiber laser unit FLU1 to FLUN. The MOPA type fiber laser unit includes a master oscillator (MO) unit and a power amplifier (PA) unit arranged after the MO unit. The MO unit generates seed light, and the PA unit generates laser light by amplifying the power of the seed light. In the MOPA type fiber laser unit, the MO unit may be a resonator type fiber laser unit, or any of a semiconductor laser unit, a solid-state laser unit, a liquid laser unit, and a gas laser unit. May be good.

Further, the fiber laser system LFS may employ any one of a semiconductor laser unit, a solid-state laser unit, a liquid laser unit, and a gas laser unit as the laser unit described in the claimed range.

[Fourth Embodiment]
The fiber laser apparatus FLA according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram of the fiber laser apparatus FLA.

The fiber laser apparatus FLA employs the optical cable 100 described in the second embodiment as the output delivery fiber ODF. The description of the optical fiber assembly 10 (see FIGS. 1 and 2) described in the first embodiment and the description of the optical cable 100 (see FIG. 3) described in the second embodiment are described in the present embodiment. Omit. The fiber laser device FLA is an example of the laser system described in the claims.

Further, the expression “connection” used in the present embodiment means that the two members are optically connected.

As shown in FIG. 5, the fiber laser unit FLU1 included in the fiber laser apparatus FLA has the same configuration as the fiber laser unit FLU1 provided in the fiber laser system FLS (see FIG. 4). Therefore, in this embodiment, the description of the fiber laser unit FLU1 will be omitted.

Further, unlike the fiber laser system FLS, the fiber laser apparatus FLA does not need to combine the laser beams generated by each of the plurality of fiber laser units FLU1 to FLUN. Therefore, the fiber laser apparatus FLA can omit the output combiner OC included in the fiber laser system FLS. As a result, in the fiber laser apparatus FLA, the incident end face of the output delivery fiber ODF is coupled to the fiber laser unit FLU1. As in the case of the fiber laser system FLS, the fiber laser device FLA may adopt a resonator type fiber laser unit or a MOPA type fiber laser unit as the fiber laser unit FLU1. Good. When the fiber laser device FLA employs a MOPA type fiber laser unit as the fiber laser unit FLU1, the MO unit may be a resonator type fiber laser unit, a semiconductor laser unit, a solid-state laser unit, or a liquid. It may be either a laser unit or a gas laser unit. Further, the fiber laser apparatus FLA may employ any one of a semiconductor laser unit, a solid-state laser unit, a liquid laser unit, and a gas laser unit as the laser unit described in the claimed range.

The fiber laser apparatus FLA configured in this way has the same effect as that of the optical fiber assembly 10.

As shown in FIG. 4, the incident end face of the output delivery fiber ODF included in the output head 1 according to one aspect of the present invention is connected to at least one fiber laser unit FLU1 to FLUN via an output combiner OC. It can also be coupled to one fiber laser unit FLU1 as shown in FIG.

10 Optical fiber assembly 11 Optical fiber core wire (optical fiber)
11a Bare fiber 11b Resin layer (second resin layer)
11b1 Inner layer 11b2 Outer layer 12a Detection line (first detection line)
12b detection line (second detection line)
13 Tear string 14 Resin layer (first resin layer)
15 Thermistor 20 Inner tube 30 Outer tube 31 Bellows 32 Protective layer 100 Optical cable LU laser unit OH output head LS laser system

Claims (7)

With optical fiber
One or more detection lines and one or more tear cords arranged along the outer surface of the optical fiber, each of which is spirally wound in at least a part of the optical fiber without intersecting with each other. With one or more detection lines and one or more tearstrings
In at least a part of the sections, the one or more detection lines, the one or more tear cords, and the first resin layer that directly covers the outer surface , and the one or more detection lines and It comprises a first resin layer that adheres each of the one or more torn cords to the outer surface .
An optical fiber assembly characterized by this. The one or more detection lines are a plurality of detection lines.
The optical fiber assembly according to claim 1. Two of the plurality of detection lines are designated as the first detection line and the second detection line.
One end of the first detection line and the second detection line are conducting with each other via a thermistor.
The optical fiber assembly according to claim 2. The first resin layer is provided over a section of one pitch or more in the entire section of the optical fiber.
The optical fiber assembly according to any one of claims 1 to 3. The optical fiber includes a bare fiber and a second resin layer covering the bare fiber.
The melting point of the resin constituting the surface layer of the second resin layer is higher than the melting point of the resin constituting the first resin layer.
The optical fiber assembly according to claim 4. The optical fiber assembly according to any one of claims 1 to 5.
It comprises one or more tubes accommodating the optical fiber assembly.
An optical cable that features that. The optical cable according to claim 6 and
A laser unit optically coupled to one end of the optical cable and
It comprises an output head, which is optically coupled to the other end of the optical cable.
A laser system characterized by that.

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