WO2015136924A1

WO2015136924A1 - Optical fiber device

Info

Publication number: WO2015136924A1
Application number: PCT/JP2015/001324
Authority: WO
Inventors: 仁科　倫太郎
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2014-03-12
Filing date: 2015-03-11
Publication date: 2015-09-17

Abstract

　This optical fiber device has an optical fiber, a fluorescent member, and a photodetector. The optical fiber has a transmission channel which has a core and cladding surrounding the core, and a sheath surrounding the transmission channel. The fluorescent member contacts the transmission channel in a stripped section where the sheath of the optical fiber has been stripped. The photodetector detects light of the emission wavelength of the fluorescent member.

Description

Fiber optic equipment

The present disclosure relates to an optical fiber device that guides laser light from free space to an end face of an optical fiber.

In recent years, laser light with high output and high energy concentration efficiency has been used for processing such as welding and cutting. In addition, by using an optical fiber for transmission of laser light to the vicinity of a processing part, the application range of laser light, such as combining with application equipment such as a robot having a high degree of freedom, has been expanded.

In order to transmit laser light through an optical fiber, it is necessary to guide (inject) the laser light emitted from the laser oscillator into the optical fiber. In addition, it is necessary to guide laser light already transmitted through an optical fiber to another optical fiber used for application equipment.

Therefore, an optical fiber device that collects laser light propagating in free space and makes it incident inside from the end face of the optical fiber is required. This technology is such that high-power laser light is once emitted from a transmission source optical fiber into free space, and the laser light is condensed in free space and incident again on the transmission destination optical fiber, that is, fiber coupling. It is also necessary for the connect device that performs the above. Furthermore, this technique is also required for a switch device that selects one optical fiber from a plurality of optical fibers that are laser beam transmission destinations and makes laser light incident.

Usually, an optical fiber is composed of a core, a clad, and a coating resin. The core is a part through which light propagates, the clad is a part that confines light in the core, and the coating resin is a part that protects the core and the clad. In order to propagate a laser beam incident on an optical fiber, the laser beam propagating in free space is condensed to a diameter equal to or less than the diameter of the core of the optical fiber with a condensing lens and incident on the core from the end face of the optical fiber. . Therefore, alignment of the optical system is essential. That is, in order to prevent loss of laser light due to leakage into the coating resin while maintaining the quality of the transmitted laser light, it is necessary to make the laser light incident on the core with high accuracy.

The prior art described in Patent Document 1 will be described with reference to FIG.

FIG. 16 is a side view of a conventional optical fiber device 400. As shown in FIG. 16, the conventional optical fiber device 400 includes a diffuser 403 and a detector in the radial direction of the light incident / incident end 402 of the optical fiber 401 in order to know in advance damage to the light incident / incident end 402 of the optical fiber 401. 404. Then, the intensity of the laser beam reflected in the radial direction is detected by the detector 404, and the damage of the exit / incident end 402 of the optical fiber 401 is determined based on the detected intensity of the laser beam.

JP 2005-500528 Gazette

However, the conventional optical fiber device can detect an abnormality of the end face of the optical fiber, but cannot determine whether the laser light is incident on the clad due to misalignment of the laser light.

In general optical fibers, the refractive index of the coating resin is higher than the refractive index of the cladding. Therefore, when part of the laser light is incident on the clad due to misalignment of the laser light, the laser light is absorbed by the coating resin while propagating through the optical fiber. Thereby, the output of the laser beam emitted from the emission end face of the optical fiber is reduced. Furthermore, the energy of the laser light absorbed by the coating resin is converted into thermal energy, and the coating resin may generate heat and be damaged.

On the other hand, an optical fiber that transmits a high-power laser beam represented by a fiber laser has a refractive index of the coating resin lower than that of the cladding. In this optical fiber, even when laser light is incident on the clad, the laser light is totally reflected at the interface between the clad and the coating resin. That is, since the clad serves as the second core and the coating resin serves as the second clad, the light incident on the clad also propagates to the output end of the optical fiber. Since this optical fiber has two parts that function as a clad, it is also called a double clad fiber.

When the laser light is incident on the clad in the double clad fiber, the power of the laser light emitted from the emission end face of the double clad fiber is not different from that when the laser light is incident only on the core. Further, the emission angle of the laser beam emitted from the emission end face of the double clad fiber does not change. For this reason, since the diameter of the laser beam at the emission end face of the optical fiber which is a double clad fiber is increased by the amount including the cladding, the beam quality of the emitted laser beam is deteriorated.

When performing laser processing such as welding or cutting with a laser, an optical system called a processing head for condensing laser light is attached after the output end of the optical fiber, and the processing target is irradiated with the focused laser light. If the beam quality of the laser beam is deteriorated, the spot diameter of the focused laser beam is increased, the light density at the processing point is lowered, and desired optical characteristics cannot be obtained. When carrying out laser processing, the processing head repeatedly moves and high-precision positioning control of the processing head is necessary, and the processing head is required to be lightweight and small.

Furthermore, when a double clad fiber that propagates laser light is also used for the clad, the light propagating through the clad is also output from the output end face of the optical fiber. Therefore, it is difficult to determine whether the laser beam is incident only on the core from the output and angle of the emitted laser beam.

In order to emit laser light having a desired optical characteristic from the emission end face of the optical fiber, it is important that the laser light incident on the optical fiber is shifted from the core and not incident on the cladding. If the abnormality of the transmission line can be detected, the reliability of the laser processing apparatus can be improved.

As described above, when the misalignment occurs and the laser light enters the optical fiber cladding, the coating resin of the optical fiber may be damaged, or the beam quality of the laser light emitted from the optical fiber exit end face Gets worse.

Therefore, the present disclosure provides an optical fiber device that can detect that laser light is incident on the clad of the optical fiber, thereby preventing deterioration of the reliability of the optical fiber device and the quality of the laser light.

In order to solve the above problems, an optical fiber device according to the present disclosure includes an optical fiber, a fluorescent member, and a photodetector. The optical fiber has a transmission line having a core and a clad surrounding the core, and a coating surrounding the transmission line. The fluorescent member is in contact with the transmission line at the peeling portion where the coating of the optical fiber is peeled off. The photodetector detects light having the emission wavelength of the fluorescent member.

With the above configuration, the optical fiber device according to the present disclosure can detect that laser light is incident on the clad of the optical fiber, thereby preventing deterioration of the reliability of the optical fiber device and the quality of the laser light. it can.

FIG. 1 is a cross-sectional view illustrating a configuration of an optical fiber device according to an embodiment. FIG. 2 is a cross-sectional view perpendicular to the extending direction of the optical fiber according to the embodiment. FIG. 3 is a cross-sectional view of an optical fiber having a support layer according to an embodiment perpendicular to the stretching direction. FIG. 4 is a cross-sectional view in the stretching direction of an optical fiber having no support layer according to the embodiment, and (a) is a diagram showing the propagation of laser light when the refractive index of the coating resin is higher than that of the cladding. (B) is a figure which shows propagation | transmission of the laser beam in case the refractive index of coating resin is lower than a clad. FIG. 5 is a cross-sectional view of an optical fiber having a support layer according to the embodiment in the stretching direction. FIG. 5A is a diagram illustrating propagation of laser light when the refractive index of the coating resin is higher than that of the support layer. FIG. 6B is a diagram showing the propagation of laser light when the refractive index of the coating resin is lower than that of the support layer. 6A and 6B are cross-sectional views of the optical fiber of the embodiment in the extending direction. FIG. 6A is a schematic diagram of laser light incident on an optical fiber having no end cap, and FIG. 6B is light having an end cap. It is a schematic diagram of the laser beam which injects into a fiber. FIG. 7 is a side view showing the main configuration and operation of the optical fiber device according to the embodiment. FIG. 8 is a cross-sectional view of the present embodiment where the fluorescent member is in contact with the transmission path of the optical fiber. FIG. 9 is a cross-sectional view of the optical fiber and the fluorescent member, showing variations in the arrangement of the fluorescent member. FIG. 10 is a cross-sectional view of an optical fiber and a fluorescent member showing a variation in which a plurality of fluorescent members emitting different fluorescence are arranged. FIG. 11 is a cross-sectional view perpendicular to the extending direction in which the fluorescent member is held by a connector. FIG. 12 is a cross-sectional view in the extending direction showing an optical fiber integrated with a fluorescent member. FIG. 13 is a cross-sectional view showing an optical fiber device in which a photodetector is provided in the connector. FIG. 14 is a cross-sectional view in the extending direction of an optical fiber device having two fluorescent members emitting different fluorescence. FIG. 15 is a side view showing a laser output confirmation device having an optical fiber device according to the embodiment. FIG. 16 is a side view of a conventional optical fiber device.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same components are denoted by the same reference numerals, and the description thereof may be omitted.

(Embodiment)
<Main configuration of optical fiber device 100>
FIG. 1 is a cross-sectional view showing a configuration of an optical fiber device 100 according to the present embodiment. As shown in FIG. 1, the optical fiber device 100 includes an optical fiber 101, a fluorescent member 108, and a photodetector 110.

As shown in FIG. 1, the optical fiber device 100 includes a connector 201, and includes an optical fiber 101, a fluorescent member 108, and an end cap 112 as an integral unit. Moreover, the optical fiber 101 which has the housing 203 and was integrated by the connector 201 can be hold | maintained so that attachment or detachment with respect to the housing 203 is possible. The housing 203 further holds the optical filter 111 and the photodetector 110 at predetermined positions, and the condenser lens 102 can adjust the focal position of the laser beam 107 incident through the alignment device 204. Installed.

In order for the laser beam 107 to be incident on the optical fiber 101 and propagated, the laser beam 107 propagating in free space is condensed by the condensing lens 102 to be equal to or smaller than the diameter of the core 103 of the optical fiber 101, and the optical fiber 101. It is necessary to enter the core 103 from the end face. The optical fiber 101 includes at least a core 103, a clad 104, and a coating resin 105. The core 103 is a site where the laser beam 107 propagates, the clad 104 is a site where the laser beam 107 is confined in the core 103, and the coating resin 105 is a site that protects the core 103 and the clad 104.

The core 103 has a higher refractive index than the clad 104, and the laser beam 107 is totally reflected at the interface between the core 103 and the clad 104 using the difference in refractive index between the core 103 and the clad 104, thereby confining the laser beam 107 in the core 103. While propagating. When the refractive index difference between the core 103 and the clad 104 is large, the total reflection angle (critical angle) also increases, so that the laser beam 107 having a larger incident angle can be incident and propagated. In FIG. 1, an optical fiber 101 having a support layer 106 is illustrated. In the optical fiber having the support layer 106, the core 103, the clad 104, and the support layer 106 are collectively referred to as a transmission line, and in the optical fiber having no support layer 106, the core 103 and the clad 104 are collectively referred to. It is called a transmission line.

When the high-power laser beam 107 is used, the end cap 112 is fused and connected to the end face of the optical fiber 101 to prevent damage to the end face of the optical fiber 101. The end cap 112 will be described later.

First, each component of the optical fiber 101 will be described in detail.

The optical fiber 101 includes a core 103, a clad 104, and a coating resin 105. The material of the core 103 and the clad 104 is made of glass with low optical loss or plastic with low optical loss. The core 103 has a refractive index higher than that of the clad 104, and the laser beam 107 propagates through the core 103 due to total reflection of the laser beam 107 due to a difference in refractive index between the core 103 and the clad 104.

FIG. 2 is a cross-sectional view perpendicular to the extending direction of the optical fiber 101 of the present embodiment. There is a core 103 at the center of the optical fiber 101, a clad 104 around the core 103, and a coating resin 105 around the clad 104.

When propagating a high-power laser beam 107 exceeding 100 W, the core 103 of the optical fiber 101 is made of pure quartz glass, and the cladding 104 is made of doped quartz glass containing fluorine or boron and having a refractive index lower than that of quartz glass. in use.

Quartz glass is a material that has low optical loss, heat resistance, and little thermal expansion. Therefore, when using a high-power laser beam 107, an optical fiber 101 made of quartz glass is usually used. The numerical aperture NA of the optical fiber 101 made of quartz glass is 0.12, 0.15, 0.22, and the core diameter of the optical fiber 101 is φ100, φ200, φ400, φ600 μm, or the like.

By the way, when performing laser welding or the like, the end of the optical fiber 101 on the emission side of the laser beam 107 is attached to the tip of the arm of the processing robot, and the optical fiber 101 is repeatedly bent and swiveled. Therefore, high mechanical strength of the optical fiber 101 is required. The optical fiber 101 used for such an application further has a support layer 106 around the cladding 104, and the outer diameter of the transmission line is increased to increase the mechanical strength of the optical fiber.

FIG. 3 is a cross-sectional view of the optical fiber 101 having the support layer 106 perpendicular to the stretching direction. There is a core 103 at the center of the optical fiber 101, a clad 104 around the core 103, a support layer 106 around the clad 104, and a coating resin 105 around the support layer 106. The support layer 106 is often made of the same material as that of the core 103, and is pure quartz glass when the high-power laser beam 107 is used. The outer diameter of the support layer 106 of the optical fiber 101 is φ250, φ500, φ750, φ1000 μm, or the like.

In the optical fiber 101, the “support layer” in this specification may be simply expressed as “cladding”. In this specification, in order to clarify that the optical function is different from that of the clad 104, it is expressed as “support layer”.

The material of the coating resin 105 of the optical fiber 101 is a heat-resistant silicone resin or a heat-resistant fluororesin when the high-power laser beam 107 is used. In order to prevent the coating resin 105 from being damaged by the laser beam 107 propagating through the cladding 104 or the support layer 106, a material having a lower refractive index than that of the cladding 104 or the support layer 106 is used for the coating resin 105. When a material having a low refractive index is used for the coating resin 105, the laser beam 107 is totally reflected at the interface between the cladding 104 and the coating resin 105, and the laser beam 107 propagates through the cladding 104. Thereby, since the laser beam 107 does not travel toward the coating resin 105, damage to the coating resin 105 can be reduced.

However, the laser light 107 incident on the clad 104 of the optical fiber 101 is propagated to the emission end face of the optical fiber 101, and the optical characteristics of the laser light 107 emitted from the optical fiber 101 are deteriorated. On the other hand, for example, a cooling device is provided at a portion where the laser beam 107 leaks from the core 103 to the cladding 104, such as a fusion connection point where optical fibers are connected to each other, and the cladding 104 or A method of absorbing and removing the laser beam 107 propagating through the support layer 106 is used.

Next, the laser beam 107 propagating through the optical fiber 101 will be described.

The propagation of the laser beam 107 in the optical fiber 101 without the support layer 106 will be described. FIG. 4 is a cross-sectional view of the optical fiber 101 having no support layer in the stretching direction, and FIG. 4A is a diagram showing the propagation of the laser light 107 when the refractive index of the coating resin 105 is higher than that of the cladding 104. FIG. 6B is a diagram illustrating the propagation of the laser beam 107 when the refractive index of the coating resin 105 is lower than that of the cladding 104. The portion from which the coating resin 105 is removed (peeling portion) is in contact with air, and the absolute refractive index of air is 1.0, which is lower than the absolute refractive index of the solid substance. Therefore, the laser beam 107 propagates through a portion (peeling portion) where the air serves as a clad to remove the coating resin 105.

As shown in FIG. 4A, the laser beam 107 (solid line) incident on the core 103 of the optical fiber 101 is emitted from the emission end face of the optical fiber 101 as it is. However, the laser beam 107 (broken line) incident on the clad 104 of the optical fiber 101 travels from the clad 104 toward the coating resin 105, and the laser beam 107 is incident on the coating resin 105 due to the refractive index. It is absorbed by the resin 105 and disappears. The absorbed laser beam 107 is converted from light energy to heat energy, and the coating resin 105 generates heat.

As shown in FIG. 4B, the laser beam 107 (solid line) incident on the core 103 of the optical fiber 101 is emitted as it is from the emission end face of the optical fiber 101 as in FIG. Then, the laser beam 107 (broken line) incident on the clad 104 of the optical fiber 101 propagates through the clad 104 and the core 103 while being totally reflected between the clad 104 and the coating resin 105 due to the relationship of the refractive index. 101 exits from the exit end face.

Meanwhile, the propagation of the laser beam 107 in the optical fiber 101 having the support layer 106 will be described. FIG. 5 is a cross-sectional view of the optical fiber 101 having the support layer 106 in the stretching direction. FIG. 5A is a diagram illustrating the propagation of the laser light 107 when the refractive index of the coating resin 105 is higher than that of the support layer 106. FIG. 8B is a diagram illustrating the propagation of the laser beam 107 when the refractive index of the coating resin 105 is lower than that of the support layer 106. The portion from which the coating resin 105 is removed (peeling portion) is in contact with air, and the absolute refractive index of air is 1.0, which is lower than the absolute refractive index of the solid substance. Therefore, the laser beam 107 propagates through a portion (peeling portion) where the air serves as a clad to remove the coating resin 105.

As shown in FIG. 5A, the laser beam 107 (solid line) incident on the core 103 of the optical fiber 101 is emitted from the emission end face of the optical fiber 101 as it is. However, the laser beam 107 (broken line) incident on the clad 104 of the optical fiber 101 travels from the clad 104 toward the support layer 106. Further, due to the refractive index, the laser beam 107 is incident on the coating resin 105 from the support layer 106 and is absorbed by the coating resin 105 and disappears.

As shown in FIG. 5B, the laser beam 107 (solid line) incident on the core 103 of the optical fiber 101 is emitted as it is from the emission end face of the optical fiber 101, as in FIG. The laser beam 107 (broken line) incident on the clad 104 travels from the clad 104 toward the support layer 106 due to the refractive index. However, the laser beam 107 is totally reflected between the support layer 106 and the coating resin 105 due to the refractive index, and the laser beam 107 propagates through the cladding 104, the support layer 106, and the core 103, and is emitted from the optical fiber 101. It is emitted from the end face.

By the way, when the high-power laser beam 107 is used, a method of melting and connecting a transparent body block called an end cap 112 to the input / output end surface of the optical fiber 101 is used in order to prevent damage to the input / output end surface. The core 103 on the entrance / exit end face of the optical fiber 101 is in contact with air (exposed), and is easily damaged because the optical strength is reduced.

6A and 6B are cross-sectional views of the optical fiber 101 according to the present embodiment in the extending direction. FIG. 6A is a schematic diagram of the laser beam 107 incident on the optical fiber 101 having no end cap, and FIG. 3 is a schematic diagram of laser light 107 incident on an optical fiber 101 having a cap 112. FIG.

6 (a) and 6 (b), the end face of the optical fiber 101 can be covered by fusing the end cap 112 to the end of the optical fiber 101. The laser beam 107 incident on the optical fiber 101 and the laser beam 107 emitted from the optical fiber 101 travel in a conical shape. Therefore, the outer diameter of the laser beam 107 at the exposed end face of the end cap 112 is larger than the outer diameter of the laser beam 107 at the end face of the core 103 of the optical fiber 101 covered with the end cap 112. By having the end cap 112, the energy density of the laser beam 107 on the end face of the end cap 112 exposed to air is reduced, and damage to the end face of the optical fiber 101 is prevented.

The material of the end cap 112 is preferably heat-resistant pure quartz glass, and the end face of the end cap 112 is preferably subjected to anti-reflection coating. For example, when an end cap 112 having a length of 10 mm and a diameter of φ5 mm and an optical fiber 101 having a core diameter of φ100 μm are used to focus laser light 107 having an NA of 0.12 to φ100 μm, the laser beam 107 on the end face of the end cap 112 The outer diameter is approximately 2.4 mm as calculated geometrically. As a result, the energy density of the laser beam 107 at the end face of the end cap 112 is reduced to 0.0017 times the energy density of the end face of the optical fiber 101 without the end cap 112.

<Method for Manufacturing Optical Fiber Device 100 of the Present Disclosure>
A typical manufacturing method of the optical fiber device 100 of the present disclosure will be described below. The optical fiber 101 has a support layer 106, and an example in which an end cap 112 is connected to an end face to form a connector at the end will be described with reference to FIG.

First, the coating resin 105 near the end of the optical fiber 101 cut to a required length is removed with a stripper to expose the support layer 106. In order to completely remove the coating resin 105, the portion from which the coating resin 105 has been removed is washed with ethanol. Thereafter, the end surface of the optical fiber 101 is cleaved to end the surface. When the high-power laser beam 107 is used, the end cap 112 is fused and connected to the end face of the cleaved optical fiber 101. On the other hand, the fluorescent member 108 is processed into a desired dimension, and the contact surface with the support layer 106 is polished.

Next, the end of the optical fiber 101 is made into a connector. A connector 201 having a through hole into which the fluorescent member 108 is inserted in advance is prepared. The position of the through hole is provided at a position where the fluorescent member 108 is brought into contact with the support layer 106. In the portion where the fluorescent member 108 is in contact, the coating resin 105 of the optical fiber 101 is removed and the surface of the support layer 106 is exposed. is doing.

Then, the end of the optical fiber 101 is made into a connector. Thereafter, the fluorescent member 108 is inserted from the through hole and brought into contact with the clad 104, and an adhesive is applied from the through hole of the connector 201 to fix the fluorescent member 108 and the connector 201. After the adhesive is cured, the through hole is covered so that the laser beam 107 does not leak from the through hole of the connector 201.

In order to insert and fix the connector 201, a housing 203 is separately manufactured as shown in FIG. An aligning device 204 for finely adjusting the position of the condenser lens 102 is attached inside the housing 203. The position of the condensing lens 102 can be moved by the aligning device 204, and the condensing position of the laser beam 107 that has passed through the condensing lens 102 can be finely adjusted.

The housing 203 is processed so that the photodetector 110 and the optical filter 111 can be attached. The photodetector 110 is attached at a position where the fluorescent light 109 is easy to receive, and the incident laser beam 107 is not blocked in consideration of the amount of movement of the alignment device 204. The photodetector 110 is electrically wired and is connected to a measuring device not shown here. The optical filter 111 is attached to the front surface of the light receiving surface of the photodetector 110.

Finally, after the condensing lens 102 is attached to the aligning device 204, the optical fiber 101 formed as a connector is inserted into the housing 203 and fixed.

<Operation of Optical Fiber Device 100 of Present Disclosure>
Hereinafter, the operation of the optical fiber device 100 of the present embodiment will be described with reference to the drawings. FIG. 7 is a side view showing the main configuration and operation of the optical fiber device 100 according to the present embodiment. FIG. 7 shows only main components for explaining the operation and action of the optical fiber device 100 of the present embodiment.

Usually, when the laser beam 107 condensed by the condenser lens 102 is incident only on the core 103 of the optical fiber 101, the laser beam 107 propagates through the core 103 and reaches the emission end face of the optical fiber 101. However, some laser light 107 may enter the clad 104 of the optical fiber 101 due to vibration or impact.

The misalignment includes (a) a deviation in the direction perpendicular to the axis of the optical fiber 101, (b) a deviation in the direction of the axis of the optical fiber 101, and (c) the axis of the optical fiber 101 and the laser beam 107. Are the three components of the angle deviation of the optical axis. With respect to such misalignment, the optical fiber device 100 according to the present embodiment has a structure in which the position of the condenser lens 102 is moved and adjusted. The alignment device 204 of the present embodiment includes a feed screw used in a micrometer so that each shift component can be finely adjusted.

The fluorescent member 108 is disposed so as to be in contact with the outside of the clad 104 from which the coating resin 105 in the vicinity of the incident end of the optical fiber 101 has been removed. As shown in FIG. 7, in the optical fiber 101 having the support layer 106, the fluorescent member 108 is brought into contact with the outside of the support layer 106. That is, the fluorescent member 108 is brought into contact with the transmission path of the optical fiber 101. In either case, since the clad 104 and the fluorescent member 108 are optically coupled, the laser beam 107 propagating through the clad 104 reaches the fluorescent member 108.

The laser beam 107 propagating in the free space is condensed by the condenser lens 102 and adjusted so as to enter the core 103. However, as shown in FIG. 7, when a misalignment occurs and a part of the laser beam 107 enters the clad 104, the laser beam 107 reaches the fluorescent member 108. The laser beam 107 reaching the fluorescent member 108 is absorbed by the fluorescent substance contained in the fluorescent member 108, and the fluorescent member 108 emits fluorescence 109.

Fluorescence 109 is emitted in all directions. The fluorescence 109 passes through the support layer 106, the clad 104, and the core 103 and is emitted from the surface of the optical fiber 101 and the end face of the end cap 112 to free space. Alternatively, the light is emitted directly from the fluorescent member 108 to the free space. The intensity of the fluorescence 109 increases as the laser beam 107 incident on the clad 104 increases.

The fluorescent member 108 will be described in detail below. FIG. 8 is a cross-sectional view of the present embodiment where the fluorescent member 108 is in contact with the transmission path of the optical fiber 101. Since the coating resin 105 is removed, the coating resin 105 is not described. The fluorescent member 108 is brought into contact with the outside of the support layer 106. In the case of the optical fiber 101 without the support layer 106, the fluorescent member 108 is brought into contact with the outside of the clad 104.

It is desirable to use a transparent or translucent material for the base material of the fluorescent member 108, and when using the high-power laser beam 107, heat-resistant quartz glass or crystal is desirable.

When the laser beam 107 enters the fluorescent member 108, the fluorescent material absorbs the laser beam 107 and excites electrons in the fluorescent material. Then, when the excited electrons return to the stable state, fluorescence 109 having a wavelength different from that of the laser beam 107 is emitted. The fluorescence 109 is emitted in all directions and has no directivity. Since the range of wavelengths to be absorbed for each fluorescent material is determined, the fluorescent material of the fluorescent member 108 is selected in consideration of the wavelength of the laser beam 107 to be used.

For example, when laser light 107 having a wavelength of 0.98 μm is used as incident light, quartz glass containing a material Yb ₂ O ₃ containing ytterbium element is used as the fluorescent member 108, and the fluorescent member 108 emits light having a wavelength of 0.98 μm. Absorbs and emits fluorescence with a wavelength of 1.06 μm. Further, when quartz glass containing the material Er ₂ O ₃ containing erbium element is used as the fluorescent member 108, the fluorescent member 108 absorbs the laser beam 107 having a wavelength of 0.98 μm and emits fluorescence of 1.55 μm. .

The shape of the fluorescent member 108 is polished or cleaved so that the contact surface with the optical fiber 101 is not uneven, and is processed into a smooth surface. Or you may process into the surface of the circular groove | channel which follows the cylindrical side surface of the optical fiber 101, or the V-groove which is easy to hold | maintain a cylindrical shape. Alternatively, instead of a structure in which the fluorescent member 108 is in contact with the optical fiber 101, a structure in which a fluorescent material is contained in the support layer 106 of the optical fiber 101 is also possible.

The fluorescent member 108 is not limited to one type, and two or more types of fluorescent members 108 that emit fluorescent light 109 having different wavelengths may be used simultaneously. For example, the fluorescent member 108 containing Yb ₂ O ₃ and the fluorescent member 108 containing Er ₂ O ₃ may be brought into contact with one optical fiber 101 at the same time.

The optical fiber 101 used in the fiber laser contains a rare earth element in the quartz glass core 103, and the optical fiber 101 can also be used as the fluorescent member.

Next, the photodetector 110 will be described.

The photodetector 110 is disposed at a position where the fluorescence 109 emitted from the fluorescent member 108 can be detected. In the example of the configuration shown in FIG. 7, the fluorescent light 109 emitted from the end cap 112 to the free space is installed at a position where it can be detected.

As the photodetector 110, a photodiode may be used. A photodiode is a semiconductor that converts light into an electrical signal. Because of its small size and high-speed response, it is optimal for use as the photodetector 110. The amount of electricity flowing changes depending on the intensity of the received light, and the change in the amount of electricity is read to detect the occurrence of misalignment when the amount of electricity exceeding a specific level flows.

Since the photodetector 110 has a range of wavelengths that can be measured, the one that can measure the fluorescence 109 is selected. Preferably, by using the photodetector 110 that does not react to the wavelength of the laser beam 107 but reacts to the wavelength of the fluorescence 109, it is not necessary to use an optical filter 111 described later.

The light detector 110 receives not only the fluorescence 109 but also the scattered light of the laser beam 107, and may detect an axial deviation even though no axial deviation has occurred. In order to prevent this, an optical filter 111 having wavelength selectivity is disposed in front of the light receiving surface of the photodetector 110. Since the fluorescence 109 and the laser beam 107 have different wavelengths, an optical filter 111 having a characteristic of passing the fluorescence 109 and blocking the laser beam 107 is used.

Accordingly, the scattered light of the laser beam 107 incident on the core 103 is not detected by utilizing the difference between the wavelengths of the laser beam 107 and the fluorescence 109, and it is determined whether the laser beam 107 is incident on the clad 104. Can do.

A suitable combination is selected in consideration of the wavelength and intensity of the photodetector 110, the optical filter 111, and the laser beam 107 and the fluorescence 109.

By configuring as described above, the photodetector 110 can detect the intensity of the fluorescence 109 emitted from the fluorescent member 108.

When the laser beam 107 incident on the optical fiber 101 is incident on the clad 104, fluorescence 109 is emitted by the fluorescent member 108. By reading the intensity of the fluorescence 109 with the photodetector 110 and issuing an alarm when the intensity of the read fluorescence 109 exceeds a certain level, the operator can confirm that the alignment error has occurred in the optical fiber device 100. I can know.

Note that the fluorescent member 108 is not limited to one type, and two or more types of fluorescent members 108 having fluorescent substances having different fluorescent wavelengths may be provided. In this case, since each fluorescent member 108 emits fluorescent light 109 having a different wavelength, the intensity ratio of the fluorescent light 109 changes depending on the position of misalignment. By reading the intensity ratio of the fluorescence 109 with the photodetector 110, it can be estimated in which direction the misalignment has occurred.

As described above, according to the optical fiber device 100 of the present embodiment, the fluorescent member emits fluorescence having a wavelength different from that of the laser beam 107 when a part of the laser beam 107 is incident on the clad. Accordingly, it is possible to detect that the laser beam 107 has entered the clad, and to prevent deterioration of the reliability of the optical fiber device and quality of the transmitted laser beam 107 caused by the incident laser beam 107 on the clad. Can do.

<Modification of Arrangement of Fluorescent Member 108>
FIGS. 9A to 9G are cross-sectional views of the optical fiber 101 and the fluorescent member 108 showing variations in the arrangement of the fluorescent member.

9A, four fluorescent members 108 are in contact with the outside of the clad 104 of the optical fiber 101 that does not have a support layer. In FIG. 9A, four fluorescent members 108 are arranged, but the number of fluorescent members 108 is not limited to four, and any number may be brought into contact. In addition, it is desirable that the fluorescent member 108 is brought into contact with the central axis of the optical fiber 101 at equal intervals. Thereby, the difference in detection sensitivity due to the direction of misalignment can be reduced.

9B, a support layer 113 containing a fluorescent material is provided around the cladding 104 of the optical fiber 101. In FIG. The support layer 113 is a fluorescent member in which the support layer 106 includes a fluorescent material. When the laser beam 107 is incident on the clad 104 of the optical fiber 101, the support layer 113 emits fluorescence 109. As described above, by disposing the support layer 113 (fluorescent member) around the entire circumference of the clad 104, misalignment in any direction can be detected.

9C, the fluorescent member 108 is arranged and integrated around the cladding 104 of the optical fiber 101, and the support layer 106 is arranged and integrated around the fluorescent member 108. Similar to FIG. 9B, by arranging the fluorescent member 108 on the entire circumference of the clad 104, misalignment in any direction can be detected. Further, by separately forming the support layer 106 and the fluorescent member 108, the functions of the fluorescent member 108 and the support layer 106 can be fully exhibited.

In FIG. 9D, four fluorescent members 108 are in contact with the outside of the support layer 106 of the optical fiber 101. In FIG. 9D, four fluorescent members 108 are arranged, but the number of fluorescent members 108 is not limited to four, and any number may be brought into contact. As in FIG. 9A, it is desirable that the fluorescent member 108 is brought into contact with the central axis of the optical fiber 101 at equal intervals. Thereby, the difference in detection sensitivity due to the direction of misalignment can be reduced.

In FIG. 9 (e), two fluorescent members 108 are in contact with the outside of the support layer 106 of the optical fiber 101. The contact surface of the fluorescent member 108 with the optical fiber 101 has a circular groove shape, and the contact area with the optical fiber 101 is increased. In FIG. 9E, two fluorescent members 108 are arranged, but the number of fluorescent members 108 is not limited to two, and any number may be brought into contact. In addition, it is desirable that the fluorescent member 108 is brought into contact with the central axis of the optical fiber 101 at equal intervals. Thereby, the difference in detection sensitivity due to the direction of misalignment can be reduced.

9 (f), the fluorescent member 108 is disposed and integrated around the support layer 106 of the optical fiber 101. FIG. This is obtained by replacing the arrangement of the support layer 106 and the fluorescent member 108 in FIG. 9C, and has the same effect as in FIG. 9C.

9 (g), a fluorescent member 115 having a core 114 containing a fluorescent substance is brought into contact with the outside of the support layer 106 of the optical fiber 101. That is, an optical fiber containing a fluorescent material in the core is used as the fluorescent member. Thereby, since the fluorescence 109 is emitted from the opposite end face of the fluorescence member 115, the fluorescence 109 can be fiber-transmitted to the photodetector 110, and the fluorescence can be easily transmitted.

<Variation of arrangement of fluorescent members emitting different fluorescence>
FIGS. 10A to 10F are cross-sectional views of the optical fiber 101 and the fluorescent member 108 showing a variation in which a plurality of fluorescent members 108 emitting different fluorescence are arranged.

10A, two different fluorescent members 108 are in contact with the outside of the cladding 104 of the optical fiber 101 that does not have a support layer. The two different fluorescent members 108 are disposed at positions symmetrical with respect to the central axis of the optical fiber 101. In FIG. 9A, two fluorescent members 108 are arranged, but the number of fluorescent members is not limited to two, and any number may be brought into contact. In addition, it is desirable that the fluorescent member 108 is brought into contact with the central axis of the optical fiber 101 at equal intervals. In the case where two fluorescent members 108 are arranged, it is easier to detect an abnormality if they are arranged in a direction in which misalignment is likely to occur in consideration of the installation environment of the optical fiber device 100 and the direction of misalignment. .

10B, three different fluorescent members 108 are in contact with the outside of the clad 104 of the optical fiber 101 that does not have a support layer. Three different fluorescent members 108 are arranged at equal intervals for each position rotated by 120 ° about the central axis of the optical fiber 101. In addition, each of the three fluorescent members 108 generates different fluorescent light 109.

10C, the fluorescent member 108 is disposed and integrated around the cladding 104 of the optical fiber 101, and the support layer 113 is disposed and integrated around the fluorescent member 108. The support layer 113 includes the support layer 106 containing a fluorescent material, and the fluorescence wavelength of the fluorescent material contained in the support layer 113 is different from the fluorescence wavelength of the fluorescent member 108. Thus, by arranging the fluorescent member 108 and the support layer 113 (fluorescent member) around the entire circumference of the clad 104, misalignment in any direction can be detected.

In FIG. 10D, another fluorescent member 108 is arranged and integrated around the cladding 104 of the optical fiber 101, and further, the fluorescent member 108 is arranged and integrated around the fluorescent member 108, and further around the fluorescent member 108. The support layer 106 is disposed and integrated. The wavelength of fluorescence by the fluorescent material contained in the inner fluorescent member 108 is different from the wavelength of fluorescence by the fluorescent material contained in the outer fluorescent member 108. Similar to (c) of FIG. 10, by arranging the fluorescent member 108 on the entire circumference of the clad 104, misalignment in any direction can be detected. Further, by separately forming the support layer 106 and the fluorescent member 108, the functions of the fluorescent member 108 and the support layer 106 can be fully exhibited.

In FIG. 10E, three different fluorescent members 108 are brought into contact with the outside of the support layer 106 of the optical fiber 101. Three different fluorescent members 108 are arranged at equal intervals for each position rotated by 120 ° about the central axis of the optical fiber 101. In addition, each of the three different fluorescent members 108 generates different fluorescent light 109.

10F, four fluorescent members 108 are brought into contact with the outside of the support layer 106 of the optical fiber 101. In FIG. The four fluorescent members 108 each include two types of fluorescent members. The same type of fluorescent member 108 is brought into contact with the central axis of the optical fiber 101 and rotated by 90 ° about the central axis. It arrange | positions at equal intervals for every position. In FIG. 10F, two fluorescent members 108 that emit two types of wavelengths of fluorescence 109 are arranged, but the present invention is not limited to this. Desirably, the fluorescent member 108 is brought into contact with the central axis of the optical fiber 101 at equal intervals.

<Detailed configuration of holding fluorescent member>
As one method for holding the fluorescent member 108 arranged as described above, there is a method in which the fluorescent member 108 is bonded to the clad 104 or the support layer 106 with a transparent resin interposed in the gap. As another method of holding the fluorescent member 108, there is a method of holding the fluorescent member 108 with an external structure so that the fluorescent member 108 is brought into contact with the clad 104 or the support layer 106. When the high-power laser beam 107 is used, since the transparent resin may be damaged in the former method, the latter method in which the transparent resin is not interposed in the gap is desirable.

In the latter method of holding the fluorescent member, it is desirable that the end of the optical fiber 101 is integrated by the connector 201. FIG. 11 is a cross-sectional view perpendicular to the extending direction, showing two examples in which the fluorescent member 108 is held by the connector 201. The structure held by the fluorescent member 108 using the connector 201 is not particularly limited to this.

11A is a cross-sectional view of the connector 201 in which a through hole for inserting the fluorescent member 108 is provided in the connector 201 in advance, and the optical fiber 101 is integrated with the connector 201 and then the fluorescent member 108 is integrated. After the optical fiber 101 and the connector 201 are integrated, the fluorescent member 108 is inserted from the outside of the through hole of the connector 201 and brought into contact with the support layer 106 of the optical fiber 101. The contacted fluorescent member 108 is bonded or mechanically fixed to the connector 201. After the fluorescent member 108 is fixed, the through hole is covered from the outside so that the fluorescent light and the laser beam 107 are not emitted to the outside.

FIG. 11B is an example of the connector 201 in which the fluorescent member 108 is installed in a guide provided on the connector 201. The fluorescent member 108 installed in the guide is constantly pressed against the support layer 106 of the optical fiber 101 by an elastic body 202 such as a spring. The through hole in FIG. 11 (a) is the guide in FIG. 11 (b), and the lid in FIG. 11 (a) also has the function of holding the elastic body 202 in FIG. 11 (b). ing.

In addition, as an example of a structure for holding the fluorescent member 108 without using an adhesive or a connector, as shown in FIGS. 9B, 9C, 10F, and 10C, FIG. Further, there is a structure in which fluorescent members 108 are arranged in a layered manner around the cladding 104 or the support layer 106 and integrated.

FIG. 12 is a cross-sectional view in the extending direction showing two examples of the optical fiber 101 in which the fluorescent member 108 is integrated. As shown in FIG. 12, the fluorescent member 108 can be held also by fusion connection that is generally performed when the optical fiber 101 is connected. Note that the structure in which the fluorescent member 108 is fused and held to the optical fiber 101 is not particularly limited to this.

12 (a) is a cross-sectional view in the stretching direction showing the optical fiber 101 having the support layer 113 containing the fluorescent material as shown in FIG. 9 (b) on the end face of the optical fiber 101. FIG. As shown in FIG. 12A, the optical fiber having the support layer 113 is fused and connected to the end of the optical fiber not having the support layer 113. Further, the end cap 112 is fused and connected to the opposite end of the optical fiber having the support layer 113. The optical fiber that does not have the support layer 113 and the optical fiber that has the support layer 113 preferably have the same outer diameter of the core 103 and the support layer 113. Further, a support layer 113 having a fluorescent material may be formed at a portion where the support layer 106 having no fluorescent material is removed at the end of the optical fiber 101. By doing in this way, the interface between optical fibers can be decreased.

In FIG. 12B, the fluorescent member 108 is arranged and integrated around the cladding 104 as shown in FIG. 9C on the end face of the optical fiber 101, and the support layer 106 is arranged around it to integrate. In this structure, the optical fiber 101 is fused and connected. Further, the end cap 112 is fused and connected to the opposite end of the optical fiber having the fluorescent member 108. The outer diameters of the core 103 and the support layer 106 are preferably the same for the optical fiber not having the fluorescent member 108 and the optical fiber having the fluorescent member 108.

Further, as shown in FIG. 9F, only an optical fiber having a structure in which the fluorescent member 108 is arranged and integrated around the clad 104 or the support layer 106 of the optical fiber 101 may be used. As described above, the entire length from the incident end to the exit end of the optical fiber has a structure containing a fluorescent material, so that an interface due to fusion splicing can be eliminated and loss due to transmission of the laser beam 107 can be reduced.

The fluorescent member 108 is not limited to one type, and a plurality of fluorescent members 108 that emit fluorescent light 109 having different wavelengths may be used simultaneously. For example, in the structure shown in FIG. 10E, misalignment occurs and the laser light 107 incident on the clad 104 reaches the fluorescent member. Here, the amount of the laser beam 107 incident on each fluorescent member 108 varies depending on the incident position of the laser beam 107 on the end face of the optical fiber 101. Thereby, the ratio of the intensity of the fluorescence 109 emitted from each fluorescent member 108 is changed, and the direction of misalignment can be specified. Since the aligning device 204 uses a plurality of feed screws, the aligning operation is facilitated by changing the push-in amount of the feed screw based on the intensity ratio of the fluorescence 109.

<Modification of Optical Fiber Device 100 of Present Disclosure>
By the way, the photodetector 110 is not restricted to the structure attached to the housing 203 as shown in FIG. That is, the photodetector 110 may be attached to the connector 201 that holds the optical fiber 101. In this case, the photodetector 110 is attached to the connector 201 so that the fluorescence 109 emitted to the free space inside the connector 201 can be received.

FIG. 13 is a cross-sectional view showing the optical fiber device 100 in which the optical detector 110 is provided in the connector 201.

After the optical fiber 101 is integrated with the connector 201, the fluorescent member 108 is inserted through the through hole of the connector 201 and is brought into contact with the support layer 106 and fixed. Thereafter, the photodetector 110 and the optical filter 111 are attached to the connector 201. The photodetector 110 is electrically wired and connected to a measuring instrument (not shown). The optical filter 111 is attached to the front surface of the light receiving surface of the photodetector 110, in other words, between the photodetector 110 and the fluorescent member 108. Finally, the alignment device 204 is attached to the housing 203, and after the condenser lens 102 is attached to the alignment device 204, the optical fiber 101 integrated with the connector 201 is inserted into the housing 203 and fixed.

The propagation of the laser beam 107 will be described with reference to FIG. The laser beam 107 incident on the clad 104 due to the axial deviation of the laser beam 107 emits fluorescence 109 by the fluorescent member 108. The fluorescent light 109 emitted directly from the fluorescent member 108 into the free space inside the connector 201 passes through the optical filter 111 and enters the photodetector 110. Thereby, it is possible to detect that the laser beam 107 has entered the clad 104 by the photodetector 110 provided in the connector 201.

Still another optical fiber device 100 will be described with reference to FIG. FIG. 14 is a cross-sectional view in the extending direction of the optical fiber device 100 having two fluorescent members 108 that emit different fluorescence. The connector 201 is provided with two

fluorescent members

108 a and 108 b that emit fluorescence of different wavelengths, and the housing 203 is provided with two photodetectors 110. The two

fluorescent members

108 a and 108 b are brought into contact with the support layer 106 of the optical fiber 101, respectively, and are integrated with the optical fiber 101 by the connector 201.

In this configuration, two types of

optical filters

111a and 111b having wavelength selectivity are received by the two photodetectors 110, respectively, so that fluorescence of two types of wavelengths emitted by the two

fluorescent members

108a and 108b can be detected. Attach to the front of the surface. In the configuration shown in FIG. 14, the optical filter 111a corresponds to the wavelength of fluorescence emitted from the fluorescent member 108a, and the optical filter 111b corresponds to the wavelength of fluorescence emitted from the fluorescent member 108b. Each of the photodetectors 110 is electrically wired and connected to a measuring instrument (not shown).

Finally, the alignment device 204 is attached to the housing 203, and after the condenser lens 102 is attached to the alignment device 204, the optical fiber 101 integrated with the connector 201 is inserted into the housing 203 and fixed.

The propagation of the laser beam 107 will be described with reference to FIG. The laser beam 107 incident on the clad 104 due to the axial deviation of the laser beam 107 emits fluorescence 109a by the fluorescence member 108a. The fluorescent light 109 a passes through the cladding 104, the support layer 106, the core 103, and the end cap 112, and is emitted to a free space in the housing 203.

Fluorescence 109a emitted into free space travels toward the two photodetectors 110.

Optical filters

111a and 111b having wavelength selectivity are attached to the front surfaces of the light receiving surfaces of the two photodetectors 110, respectively. The fluorescence 109a is incident on the photodetector 110 corresponding to the optical filter 111a that transmits the fluorescence 109a, and the fluorescence 109a is not incident on the photodetector 110 corresponding to the optical filter 111b that does not transmit the fluorescence 109a.

With the above configuration, in addition to the determination of the incidence of the laser beam 107 on the clad 104 due to misalignment, the direction and degree of misalignment can be determined from the intensity of the fluorescent member.

<Specific examples for implementation>
Next, a specific example of the present embodiment will be described. The optical fiber device 100 has the same configuration as that shown in FIG. 1, and the manufacturing method is the same as described above. Note that the following specific examples are examples of the present disclosure and do not limit the present disclosure.

FIG. 15 is a side view showing a laser output confirmation device having the optical fiber device 100 according to the present embodiment.

The optical fiber 101 has a core 103 with a diameter of 100 μm, a cladding 104 with a diameter of 125 μm, a support layer 106 with a diameter of 500 μm, and a numerical aperture NA of 0.22. The core 103 and the support layer 106 are made of pure quartz glass, the clad 104 is made of fluorine-doped quartz glass, and the coating resin 105 is made of a silicone resin having a lower refractive index than that of the clad 104. The end cap 112 made of a pure quartz glass has a cylindrical shape with a diameter of 8 mm and is connected to the entrance / exit end face of the optical fiber 101.

The fluorescent member 108 is ytterbium-doped quartz glass. The fluorescent member 108 absorbs the laser beam 107 having a wavelength of 0.98 μm and emits fluorescence having a wavelength of 1.06 μm.

The photodetector 110 is a photodiode, and the measurement wavelength range of the photodetector 110 is 0.6 μm to 1.1 μm. The optical filter 111 has a reflectance of 99% or more with respect to light having a wavelength of 0.98 μm and a reflectance of 1% with respect to light having a wavelength of 1.06 μm.

The optical fiber 101 is integrated with the connector 201, and the fluorescent member 108 is in contact with the support layer 106. The connector 201 can be fixed by being inserted into the housing 203, and the condenser lens 102 and the alignment device 204 are installed inside the housing 203. The focal length of the condenser lens 102 is 30 mm. Further, a photodetector 110 is attached inside the housing 203, and an optical filter 111 is attached to the front surface of the light receiving surface of the photodetector 110.

The operation check of the optical fiber device 100 will be described. The operation is confirmed by entering the laser beam 107 into the optical fiber 101 and measuring the power of the laser beam 107 emitted from the emission end face. The light source of the laser beam 107 is a laser light source 301. The oscillation wavelength of the laser beam 107 emitted from the laser light source 301 is 0.98 μm, the output is 0 to 100 W, and the NA of the laser beam 107 emitted from the optical fiber 101 is 0.15. A power meter 302 that receives the emitted laser beam 107 is installed near the emission end of the optical fiber 101, thereby measuring the output of the laser beam 107 emitted from the optical fiber 101.

Next, confirmation of the laser beam 107 transmitted through the clad 104 of the optical fiber 101 will be described. The support resin 106 is exposed by removing about 10 cm of the coating resin 105 from the vicinity of the exit end of the optical fiber 101. A transparent resin 303 having a refractive index higher than that of the support layer 106 is brought into contact with the exposed side surface of the support layer 106. The laser beam 107 in the clad 104 is absorbed and removed by the transparent resin 303 having a refractive index higher than that of the support layer 106. Therefore, when the laser beam 107 is transmitted in the clad 104, the output of the laser beam at the emission end face of the optical fiber 101 is reduced, and the display value of the power meter 302 is lowered. This operation is for confirming the misalignment of the laser beam 107 and is not performed during the laser processing.

Next, alignment work using the power meter 302 will be described. First, the position of the condenser lens 102 is adjusted by the aligning device 204 while emitting a low-power laser beam 107 of about 5 W from the laser light source 301. At this time, the position of the condenser lens 102 is adjusted so that the display value of the power meter 302 is maximized. The position of the condensing lens 102 at which the display value of the power meter 302 is maximized is in a state where there is no misalignment, and the laser beam 107 is incident on the core 103 of the optical fiber 101.

After the alignment by the power meter 302 is completed, the display value of the power meter 302 and the amount of electricity emitted from the photodetector 110 are read while emitting 100 W of high-power laser light 107 from the laser light source 301. Next, the position of the condenser lens 102 is moved to intentionally cause misalignment. As the misalignment increases, the display value of the power meter 302 decreases, and conversely, the amount of electricity output from the photodetector 110 increases. From this correlation, it can be determined that light is incident on the clad 104 due to the axial deviation, and it can be confirmed that the detection of misalignment by the fluorescent member of the present disclosure functions normally.

The optical fiber device according to the present disclosure can detect that laser light has entered the clad, and can prevent deterioration of the reliability of the optical fiber device and deterioration of the quality of the transmitted laser light. Therefore, it is useful in an optical fiber device that guides light from the free space to the end face of the optical fiber.

DESCRIPTION OF SYMBOLS 100 Optical fiber apparatus 101 Optical fiber 102 Condensing lens 103,114 Core 104 Cladding 105 Coating resin 106,113 Support layer 107 Laser beam 108,108a, 108b, 115 Fluorescence member 109,109a Fluorescence 110 Photodetector 111,111a, 111b Optical filter 112 End cap 201 Connector 202 Elastic body 203 Housing 204 Alignment device 301 Laser light source 302 Power meter 303 Transparent resin 400 Optical fiber device 401 Optical fiber 402 Light incident / exit end 403 Diffuser 404 Detector

Claims

A transmission line having a core and a clad surrounding the core; and a coating surrounding the transmission line; and an optical fiber having:
In the peeling portion where the coating of the optical fiber is peeled off, a fluorescent member in contact with the transmission path,
An optical fiber device comprising: a photodetector that detects light having an emission wavelength of the fluorescent member.
The optical fiber device according to claim 1, wherein the transmission path further includes a support layer surrounding the clad.
The optical fiber device according to claim 1 or 2, wherein the fluorescent member surrounds the periphery of the transmission path.
The optical fiber device according to any one of claims 1 to 3, further comprising an end cap fused and connected to an incident end of the optical fiber.
The optical fiber device according to any one of claims 1 to 4, further comprising an optical filter provided between the photodetector and the fluorescent member and having wavelength selectivity.
The optical fiber device according to claim 1 or 2, further comprising a connector integrated with the optical fiber and the fluorescent member.
The fluorescent member is inserted into a through hole provided in the connector,
The optical fiber device according to claim 6, wherein the fluorescent member is pressed against the transmission path by an elastic body provided in the through hole.
The optical fiber device according to claim 6 or 7, further comprising an optical filter provided between the photodetector and the fluorescent member and having wavelength selectivity.
9. The optical fiber device according to claim 8, wherein the connector is integrated with the photodetector and the optical filter.
The fluorescent member includes a first fluorescent member that generates fluorescence of a first wavelength and a second fluorescent member that generates fluorescence of a second wavelength different from the first wavelength. 8. An optical fiber device according to 7.
The photodetector includes a first photodetector and a second photodetector,
A first optical filter that is provided between the first photodetector and the first fluorescent member and transmits the first wavelength;
The optical fiber device according to claim 10, further comprising: a second optical filter that is provided between the second photodetector and the second fluorescent member and transmits the second wavelength.
12. The optical fiber device according to claim 11, wherein the connector is integrated with the first photodetector, the second photodetector, the first optical filter, and the second optical filter.
The optical fiber device according to any one of claims 6 to 12, further comprising an end cap fused and connected to an incident end of the optical fiber.
14. The optical fiber device according to claim 13, wherein the connector is integrated with the end cap.