JP2019029509A - Laser device - Google Patents

Abstract

To provide a laser device capable of monitoring an output for each laser diode module.SOLUTION: A laser device comprises: a laser diode module; an output optical fiber for leading out a laser light from the laser diode module; a multiplexer for multiplexing laser light input to an input optical fiber; a fusion-bonding node for fusion bond of the output optical fiber and the input optical fiber; a light absorber which covers a clad surface of the optical fiber near the fusion-bonding node, and absorbs the laser light; a temperature sensor for measuring a temperature of the light absorber; and a monitoring-control unit for monitoring a power of laser light output by the laser diode module on the basis of a detection value of the temperature sensor.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a laser apparatus.

  In particular, optical fiber laser devices and direct diode laser devices are known as configuration examples of high-power laser devices used in the industrial field. The optical fiber laser device is a type of laser device that outputs the laser beam for excitation output from the laser diode after being amplified by the optical fiber for amplification, and the direct diode laser device is the laser device output from the laser diode. It is a type of laser device that outputs without amplification. Both types of laser devices typically include a plurality of laser diodes, and employ a configuration in which predetermined outputs are obtained by combining and using outputs from the plurality of laser diodes.

  By the way, laser diodes used in optical fiber laser devices and direct diode laser devices are modularized, and laser light is derived from each module through an optical fiber, and the optical fiber is coupled by a multiplexer. The laser beams from each module are multiplexed. In general, a plurality of laser diodes are provided in each module. Various techniques for monitoring the output from the laser diode in order to monitor the life or failure of the laser diode are also known (see, for example, Patent Documents 1 to 3).

JP 2011-192670 A Japanese Patent No. 5865977 JP 2006-292673 A

  However, when the intensity of the combined laser beam is monitored at the subsequent stage of the multiplexer, it is impossible to determine which module has a problem with the laser diode among the plurality of modules. On the other hand, if the laser beam before the multiplexing is monitored in the previous stage of the multiplexer, a lot of sensors are required. In particular, if the laser beam is detected by using a photodiode, the cost is greatly increased. It will be.

  The present invention has been made in view of the above, and an object thereof is to provide a laser device capable of monitoring the output of each laser diode module.

  In order to solve the above-described problems and achieve the object, a laser device according to an aspect of the present invention includes a laser diode module, an output optical fiber that derives laser light from the laser diode module, and an input to the input optical fiber. A multiplexer that combines the laser light, a fusion splicing point where the output optical fiber and the input optical fiber are fusion spliced, and a cladding surface of the optical fiber in the vicinity of the fusion splicing point A light absorber that absorbs the laser light, a temperature sensor that measures the temperature of the light absorber, and a monitoring control that monitors the power of the laser light output from the laser diode module from the detection value of the temperature sensor And a section.

  In the laser device according to one aspect of the present invention, a high refractive index resin covers a surface of a part of the clad of the optical fiber closer to the laser diode module than the fusion splice point and the light absorber. The high refractive index resin and the light absorber are thermally separated from each other.

  In the laser device according to one embodiment of the present invention, the high refractive index resin has a refractive index equal to or higher than that of the cladding.

  In the laser device according to one embodiment of the present invention, the light absorber has a refractive index equal to or higher than that of the cladding.

  In the laser device according to one embodiment of the present invention, the light absorber is surrounded by a heat insulating material.

  In the laser device according to an aspect of the present invention, the monitoring control unit calculates the power of the laser light output from the laser diode module from a comparison between a measurement value of the temperature sensor and a predetermined parameter. A power monitoring unit is provided.

  The laser device according to one aspect of the present invention is characterized in that the monitoring control unit includes a storage unit that stores a measurement value of the temperature sensor and a driving time of the laser diode module.

  In the laser device according to one aspect of the present invention, a plurality of the laser diode modules are provided, and the temperature sensor is provided at the fusion splicing point corresponding to each of the laser diode modules. Features.

  The laser apparatus according to one embodiment of the present invention is characterized in that the laser light combined by the multiplexer is output after being amplified by an amplification optical fiber.

  In addition, a laser device according to one embodiment of the present invention is configured to directly output laser light combined by the multiplexer.

  In the laser device according to one embodiment of the present invention, the output optical fiber and the input optical fiber are multimode optical fibers.

  The laser device according to the present invention has an effect that the output of each laser diode module can be monitored.

FIG. 1 is a diagram showing a schematic configuration of the laser apparatus according to the first embodiment. FIG. 2 is a diagram showing a schematic configuration in the vicinity of the fusion splicing point in the laser apparatus according to the first embodiment. FIG. 3 is a diagram showing the relationship between the laser beam power and the measured value. FIG. 4 is a diagram illustrating a schematic configuration of a first configuration example of the detection unit. FIG. 5 is a diagram illustrating a schematic configuration of a second configuration example of the detection unit. FIG. 6 is a diagram illustrating a schematic configuration of a second configuration example of the detection unit. FIG. 7 is a diagram illustrating a schematic configuration of a laser apparatus according to the second embodiment.

  Hereinafter, embodiments of an optical fiber laser device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below. In the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate. In addition, it should be noted that the drawings are schematic and the ratio of dimensions of each component may be different from the actual one. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of the laser apparatus according to the first embodiment. As shown in FIG. 1, the laser apparatus 100 according to the first embodiment is an optical fiber laser type apparatus. That is, the laser apparatus 100 includes a laser oscillator 110 and laser diode modules 115a to 115d, and is an apparatus configuration that outputs the excitation laser light output from the laser diode modules 115a to 115d after being amplified by the laser oscillator 110. .

  The laser oscillator 110 is provided on the amplification optical fiber 111, the first optical reflector 112 provided on the front side (left side of the paper) of the amplification optical fiber 111, and on the rear side (right side of the paper) of the amplification optical fiber 111. The second light reflector 113 is provided.

  In the amplification optical fiber 111, ytterbium (Yb) ions, which are amplification substances, are added to a core portion made of silica glass, and an inner clad made of quartz glass and an outer clad made of resin or the like are formed on the outer periphery of the core portion. It is a double clad optical fiber formed sequentially. The core of the amplification optical fiber 111 has a numerical aperture (NA) of 0.08, for example, and is configured to propagate light having a wavelength of 1000 nm to 1200 nm in a single mode. The length of the amplification optical fiber 111 is, for example, 25 m. The absorption coefficient of the core portion of the amplification optical fiber 111 is, for example, 200 dB / m at a wavelength of 1070 nm.

  The first light reflector 112 and the second light reflector 113 are composed of, for example, fiber Bragg gratings (FBGs) having different wavelength characteristics. The 1st light reflector 112 and the 2nd light reflector 113 are comprised by providing a diffraction grating in the core of an optical fiber. Further, the first light reflector 112 and the second light reflector 113 are configured as a double clad type optical fiber having an inner cladding, and are configured to propagate the light of the excitation light wavelength in the multimode in the inner cladding. It is preferable to do.

  The first light reflector 112 has a characteristic that the center wavelength is, for example, 1070 nm, the reflectivity in the wavelength band of about 2 nm width around the center wavelength and its periphery is about 100%, and light with a wavelength of 915 nm is almost transmitted. . On the other hand, the second light reflector 113 has a center wavelength that is substantially the same as that of the first light reflector 112, for example, 1070 nm, a reflectance at the center wavelength of about 10% to 30%, and a full width at half maximum of the reflected wavelength band. Is about 1 nm, and light having a wavelength of 915 nm has a characteristic of almost transmitting. For example, when excitation light with a wavelength of 975 nm is used instead of excitation light with a wavelength of 915 nm, it is preferable that the first light reflector 112 and the second light reflector 113 have a characteristic of almost transmitting light with a wavelength of 975 nm.

  As shown in FIG. 1, the laser apparatus 100 employs a so-called forward-pumped optical fiber laser configuration. That is, the laser device 100 is configured to introduce excitation laser light into the laser oscillator 110 via the first light reflector 112. The excitation laser light introduced into the laser oscillator 110 is output from each of the laser diode modules 115 a to 115 d, is combined by the multiplexer 114, and is then introduced into the laser oscillator 110. Although only four laser diode modules are shown in FIG. 1, the number is not limited to this.

  The multiplexer 114 is composed of, for example, a TFB (Tapered Fiber Bundle). The multiplexer 114 includes a front-stage signal port, a rear-stage signal port, and a plurality of multiplexing input ports that constitute both ends. A core extends between the front-side signal port and the rear-side signal port, and the core preferably has single-mode propagation characteristics at the lasing wavelength. On the other hand, the multiplexing input port is composed of an optical fiber including a (multimode) core having multimode propagation characteristics at the pumping light wavelength. The multimode optical fiber constituting each multiplexing input port is configured such that the multimode core surrounds the core of the optical fiber constituting the preceding-stage signal port.

  The rear stage signal port of the multiplexer 114 is a double clad optical fiber, and the core extending from the front stage signal port is a single mode core and extending from each multiplexing input port. Is connected to the inner cladding. Further, this double clad optical fiber is connected to the amplification optical fiber 111 via the first optical reflector 112. As a result, the light having the laser oscillation wavelength input to the front-side signal port propagates to the core of the amplification optical fiber 111 in a substantially single mode. On the other hand, the light of the pumping wavelength input to each multiplexing input port propagates to the inner cladding of the amplification optical fiber 111 in multimode.

  The laser diode modules 115 a to 115 d are connected to each multiplexing input port of the multiplexer 114. As will be described in detail later, each of the laser diode modules 115a to 115d includes an output optical fiber for deriving excitation laser light, while each multiplexing input port of the multiplexer 114 is connected to the port. Each of the output optical fibers and the input optical fibers are fusion-spliced at a fusion splice point C. In the vicinity of the fusion splice point C, a mechanism for thermally converting and monitoring the power of the excitation laser light passing through the fusion splice point C is provided.

  With the above configuration, the laser oscillator 110 oscillates a laser beam having a wavelength of 1070 nm as the first wavelength when excitation light having a wavelength of 915 nm is introduced from the laser diode modules 115a to 115d, and reflects the laser beam to the second light. Output from the device 113. Note that the laser light output from the laser oscillator 110 is irradiated onto the workpiece W via the transmission optical fiber 120 and the optical head 121.

  FIG. 2 is a diagram showing a schematic configuration in the vicinity of the fusion splicing point in the laser apparatus according to the first embodiment. Note that FIG. 2 shows the laser diode module 115 as a representative of any one of the laser diode modules 115a to 115d shown in FIG.

  As shown in FIG. 2, the laser diode module 115 includes an output optical fiber 116 that guides excitation laser light. On the other hand, each input port for multiplexing of the multiplexer 114 includes an input optical fiber 117 connected to the port. The output optical fiber 116 and the input optical fiber 117 are fusion spliced at the fusion splicing point C, and the power of the excitation laser light passing through the fusion splicing point C is near the fusion splicing point C. A detection unit 140 is provided for detecting heat by converting the heat.

  The internal configuration of the detection unit 140 will be described later with reference to FIGS. 4 to 6. However, the detection unit 140 absorbs at least the excitation laser light that passes through the fusion splice point C therein. A light absorber and a temperature sensor for measuring the temperature of the light absorber are provided. The measurement value measured by the detection unit 140 is input to the control unit 130.

  The control unit 130 is for analyzing the state of the laser diode module 115 based on the measurement value measured by the detection unit 140. The control unit 130 can be a specialized device for that purpose, but can also be realized as a function of a device that controls the entire laser device 100.

  The control unit 130 as a monitoring control unit includes a drive control unit 131, a storage unit 132, a power monitoring unit 133, and an analysis unit 134. The storage unit 132 includes a parameter storage unit 132a and a drive time storage unit 132b. However, these may be physically separated or may be logically separated in the general-purpose storage device.

  The drive control unit 131 is for controlling the magnitude of the current supplied to the laser diode module 115 in accordance with a control command from outside or inside the control unit 130. An external control command can be a user of the laser apparatus 100 or a higher-level control system that controls the laser apparatus 100. Further, the control command from the inside can be feedback obtained by monitoring the output of the laser device 100.

  The parameter storage unit 132a stores parameters for calculating the output of the laser diode module 115 from the measurement values measured by the detection unit 140. Since the measurement value measured by the detection unit 140 relates to temperature, it is necessary to calculate the output of the laser diode module 115 from the measurement value. Therefore, a parameter for associating the measurement value of the detection unit 140 with the output of the laser diode module 115 from the measurement value is stored in the parameter storage unit 132a in advance. In addition, the parameter memorize | stored in the parameter memory | storage part 132a may memorize | store the relationship between temperature and an output as a conversion table, or memorize | store a relationship mathematically. Further, since the measurement value of the detection unit 140 is typically measured as the magnitude of the current, it is possible to store the relationship between the current value and the output instead of the relationship between the temperature and the output. Further, in the laser device 100, the temperature of the substrate B may be controlled. In that case, the difference between the managed temperature and the temperature measured by the detection unit 140 is related to the output of the laser diode module 115. In this case, the parameter storage unit 132a stores parameters depending on the management temperature.

  The power monitoring unit 133 compares the parameter stored in the parameter storage unit 132a with the measurement value in the detection unit 140, and calculates the power of the laser beam output from the laser diode module 115. As described above, in the laser apparatus 100, the temperature of the substrate B may be controlled, and in this case, the power monitoring unit 133 uses the difference between the measured value in the detection unit 140 and the management temperature, and uses the laser diode. The power of the laser beam output from the module 115 is calculated.

  The drive time storage unit 132b is for storing the measurement value of the detection unit 140 and the drive time of the laser diode module 115. The measurement value of the detection unit 140 may store the measurement value as it is, or may store the value converted into the laser beam power by the power monitoring unit 133. As the driving time of the laser diode module 115, the time when the laser light is detected by the detection unit 140 can be used, but the time when the drive control unit 131 drives the laser diode module 115 can also be used. The measurement value of the detection unit 140 and the driving time of the laser diode module 115 stored in the driving time storage unit 132b are preferably cumulative values. The drive time storage unit 132b can be configured to record a log at any time, or can be configured to sequentially update the accumulated value.

  The analysis unit 134 is for analyzing the state of the laser diode module 115 based on the measurement value of the detection unit 140 and the drive time of the laser diode module 115 stored in the drive time storage unit 132b. The state of the laser diode module 115 may be, for example, a failure or a lifetime. In general, a plurality of laser diodes are provided inside the laser diode module 115, and these laser diodes reach failure or life at different timings. When these abnormalities occur, the power of the laser light output from the laser diode module 115 and passing through the fusion splice point C is reduced. The analysis unit 134 analyzes the abnormality of the laser diode from the measurement value of the detection unit 140. Further, the laser diode tends to decrease in output as the driving time accumulates. The analysis unit 134 can also estimate the replacement time of the laser diode module 115 based on the measurement value of the detection unit 140 stored in the drive time storage unit 132b and the drive time of the laser diode module 115.

  FIG. 3 is a diagram showing the relationship between the laser beam power and the measured value. One of the graphs shown in FIG. 3 is the power (P) of the laser beam passing through the fusion splicing point with respect to the driving time (t), and the other is the temperature of the detection unit with respect to the driving time (t). It is a measured value (T), and two graphs are described sharing a driving time (t).

As apparent from the relationship between the power of the laser beam passing through the fusion splicing point shown in FIG. 3 and the temperature measurement value of the detection unit, the temperature measurement value of the detection unit is the laser passing through the fusion splicing point. There is a time lag with respect to the power of light. Therefore, it is preferable that the temperature measurement value used by the power monitoring unit 133 is not the fluctuation period (D ₁ ) but the stabilization period (D ₂ ). On the other hand, the drive time of the laser diode module stored in the drive time storage unit is more accurate when the drive control unit drives the laser diode module.

(First configuration example)
FIG. 4 is a diagram illustrating a schematic configuration of a first configuration example of the detection unit. The configuration example of the detection unit 140a illustrated in FIG. 4 is a configuration corresponding to the detection unit 140 illustrated in FIG. 2, and can be applied to all the laser diode modules 115 included in the laser device 100.

  As shown in FIG. 4, the detection unit 140a is provided in the vicinity of a fusion splicing point C where the output optical fiber 116 and the input optical fiber 117 are fusion-connected. The output optical fiber 116 and the input optical fiber 117 are both multimode optical fibers, and a clad Cl having a refractive index lower than that of the core Co is formed on the outer periphery of the core Co. Cov is formed.

  In the vicinity of the fusion splice point C, the protective coating Cov of the output optical fiber 116 and the input optical fiber 117 is removed, and the core Co and the clad Cl of the output optical fiber 116 and the input optical fiber 117 are fusion spliced. Yes. The fusion splicing is a general technique for connecting optical fibers. When performing the fusion splicing, it is necessary to remove the protective coating Cov from the optical fibers. Therefore, when the laser diode module and the multiplexer are connected by an optical fiber, it is normal to provide a fusion splice point C, and the detection unit 140 detects the fusion splice point C that normally exists. What is necessary is just to provide in the vicinity.

  As described above, since the protective coating Cov is removed in the vicinity of the fusion splice point C, the light absorber 141 can be provided so as to cover the surface of the cladding Cl. The light absorber 141 is made of a material that can absorb laser light and convert the energy into heat. For example, the light absorber 141 can use black alumite treatment, electroless nickel plating, or the like. Further, it is preferable that the light absorber 141 has a refractive index equal to or higher than that of the clad Cl so that light in the clad Cl is not blocked by the refractive index difference.

  Typically, the fusion splicing is performed so that the loss at the fusion splicing point C is kept small. However, it is difficult to make the loss zero. Therefore, the laser beam passing through the fusion splice point C generates a loss depending on the magnitude of its power, and generates so-called leakage light. The light absorber 141 covering the surface of the clad Cl absorbs the leaked light and generates heat. That is, the heat generated in the light absorber 141 is due to a loss with respect to the laser light passing through the fusion splice point C, and the amount of heat generated is large in the power of the laser light passing through the fusion splice point C. It will depend on your needs.

  The temperature sensor 142 is a measuring element for measuring the temperature of the light absorber 141. For example, a thermocouple or a thermistor can be used. The position of the temperature sensor 142 is not particularly limited as long as the temperature of the light absorber 141 can be measured. However, for accurate measurement, the temperature sensor 142 is preferably disposed in a place that is not easily affected by external heat. As described above, in the laser apparatus 100, the temperature of the substrate B may be controlled. In that case, if the temperature sensor 142 is disposed between the substrate B and the light absorber 141, it is possible to suppress the external thermal influence.

(Second configuration example)
5 and 6 are diagrams illustrating a schematic configuration of a second configuration example of the detection unit. The configuration example of the detection unit 140b illustrated in FIGS. 5 and 6 is a configuration corresponding to the detection unit 140 illustrated in FIG. 2, and can be applied to all the laser diode modules 115 included in the laser device 100. .

  As shown in FIG. 5, the detection unit 140b is also provided in the vicinity of the fusion splicing point C where the output optical fiber 116 and the input optical fiber 117 are fusion-connected. The output optical fiber 116 and the input optical fiber 117 are both multimode optical fibers, and a clad Cl having a refractive index lower than that of the core Co is formed on the outer periphery of the core Co. Cov is formed. Further, in the vicinity of the fusion splice point C, the protective coating Cov of the output optical fiber 116 and the input optical fiber 117 is removed, and the core Co and the clad Cl of the output optical fiber 116 and the input optical fiber 117 are fusion spliced. Has been.

  On the other hand, the detection unit 140b is provided with a light absorber 141 so as to cover the surface of the clad Cl in the vicinity of the fusion splice point C, but the laser diode is more than the fusion splice point C and the light absorber 141. The surface of the clad Cl of the module-side output optical fiber 116 is provided so as to cover the high refractive index resin 143. The material of the high refractive index resin 143 is not limited as long as the refractive index is equal to or higher than that of the clad Cl, but an ultraviolet curable resin (such as JSR Corp. Desolite) or a US Comicix T644 can be used. . Further, the light absorber 141 preferably has a refractive index equal to or higher than that of the cladding Cl. For example, black alumite treatment or electroless nickel plating can be used.

  The laser light propagating through the output optical fiber 116 includes propagating light called clad propagating light. The clad propagation light is light that has entered the clad and propagated as it is, and is propagation light that is not originally intended. Therefore, in the detection unit 140b of the second configuration example, the high refractive index resin 143 is disposed on the laser diode module side of the light absorber 141, and the clad propagation light is removed and suppressed in advance.

  As shown in FIG. 6, the high refractive index resin 143 and the light absorber 141 are thermally separated by a heat insulating mechanism 146 made of, for example, a heat insulating material. In addition, the heat insulating mechanism 146 preferably has a configuration in which not only heat separation between the high refractive index resin 143 and the light absorber 141 but also heat influence from an external heat effect is performed. For example, the housing 144 that houses the light absorber 141 and the housing 145 that houses the high refractive index resin 143 are separated, and the housing 144 that houses the light absorber 141 is surrounded by the heat insulating mechanism 146. preferable. In this case, the light absorber 141 is surrounded by a heat insulating mechanism 146 made of, for example, a heat insulating material. On the other hand, as described above, in the laser apparatus 100, the temperature of the substrate B may be controlled, and the laser device 100 is disposed between the substrate B and the light absorber 141 in order to be disposed between the substrate B and the light absorber 141. Is preferably not thermally separated by the heat insulation mechanism 146.

  The high refractive index resin 143 removes the clad propagation light in advance as described above, but generates heat by absorbing the clad propagation light. According to the above configuration, it is possible to suppress the thermal effect associated with the removal of the clad propagation light from affecting the temperature measurement of the light absorber 141, and more accurately the power of the laser light passing through the fusion splice point C. It becomes possible to measure the thickness.

(Second Embodiment)
FIG. 7 is a diagram illustrating a schematic configuration of a laser apparatus according to the second embodiment. As shown in FIG. 7, the laser apparatus 200 according to the second embodiment is a direct diode type apparatus. That is, the laser device 200 includes laser diode modules 115 a to 115 d and a multiplexer 114, and is configured to output the laser light output from the laser diode modules 115 a to 115 d after being combined by the multiplexer 114. is there.

  The laser diode modules 115 a to 115 d are connected to each multiplexing input port of the multiplexer 114. Each of the laser diode modules 115a to 115d includes an output optical fiber for deriving laser light, while each multiplexing input port of the multiplexer 114 includes an input optical fiber connected to the port, and each output The optical fiber and the input optical fiber are fusion spliced at a fusion splicing point C.

  Therefore, the detection unit 140a or the detection unit 140b described in the first embodiment can be applied in the vicinity of the fusion splice point C, and the first embodiment is also applied to the laser device 200 according to the second embodiment. The operational effects described in the form can be achieved.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited by embodiment described above. What comprised each component of each said embodiment combining suitably is also contained in this invention. In addition, all other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are included in the present invention.

  For example, in the first embodiment described above, the embodiment has been described using the configuration example of the forward-pumped laser oscillator. However, both the backward-pumped laser oscillator and the pumping from both the front and rear sides are performed. The present invention can be appropriately implemented even with a direction-pumped laser oscillator. Further, it is possible to adopt a MOPA (Master Oscillator Power-Amplifier) configuration further including an amplifier in addition to the laser oscillator.

  Furthermore, the configuration of the detection unit described above can be generally used to measure the power of laser light passing through the fusion splicing point where the optical fibers are fusion spliced. Applicable to connection points in general. Therefore, it should be understood that the installation location of the detection unit described in the above embodiment is an example.

DESCRIPTION OF SYMBOLS 100,200 Laser apparatus 110 Laser oscillator 111 Optical fiber for amplification 112 1st optical reflector 113 2nd optical reflector 114 Multiplexer 115,115a-d Laser diode module 120 Optical fiber for transmission 121 Optical head 130 Control part 131 Drive Control unit 132 Storage unit 132a Parameter storage unit 132b Driving time storage unit 133 Power monitoring unit 134 Analysis unit 140 Detection unit 141 Light absorber 142 Temperature sensor 143 High refractive index resin 144, 145 Case 146 Heat insulation mechanism

Claims (11)

A laser diode module;
An output optical fiber for deriving laser light from the laser diode module;
A multiplexer that combines the laser beams input to the input optical fiber;
A fusion splicing point in which the output optical fiber and the input optical fiber are fusion spliced;
A light absorber that covers the surface of the cladding of the optical fiber in the vicinity of the fusion splice point and absorbs the laser light;
A temperature sensor for measuring the temperature of the light absorber;
A monitoring controller that monitors the power of the laser light output from the laser diode module from the detection value of the temperature sensor;
A laser device comprising: On the surface of the clad of a part of the optical fiber closer to the laser diode module than the fusion splicing point and the light absorber, a high refractive index resin is provided to be covered,
The high refractive index resin and the light absorber are thermally separated.
The laser apparatus according to claim 1.   The laser device according to claim 2, wherein the high refractive index resin has a refractive index equal to or higher than that of the cladding.   The laser device according to claim 1, wherein the light absorber has a refractive index equal to or higher than that of the cladding.   The laser device according to claim 1, wherein the light absorber is surrounded by a heat insulating material.   The monitoring controller includes a power monitoring unit that calculates the power of laser light output from the laser diode module based on a comparison between a measured value of the temperature sensor and a predetermined parameter. The laser device according to any one of claims 1 to 5.   The laser apparatus according to claim 1, wherein the monitoring control unit includes a storage unit that stores a measurement value of the temperature sensor and a driving time of the laser diode module. A plurality of the laser diode modules are provided,
The temperature sensor is provided at the fusion splicing point corresponding to each of the laser diode modules.
The laser apparatus according to claim 1, wherein The laser beam combined by the multiplexer is configured to output after amplification by an amplification optical fiber,
The laser apparatus according to claim 1, wherein the laser apparatus is characterized in that It is a configuration for directly outputting the laser beam combined by the multiplexer.
10. The laser device according to claim 1, wherein The output optical fiber and the input optical fiber are multimode optical fibers.
11. The laser device according to claim 1, wherein

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