JP2005158902A - Laser diode array, laser oscillator and laser processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser diode array capable of enhancing the yield in an LD bar sorting work and capable of enhancing the pumping efficiency of a laser without introducing a large scale system, and to provide a laser oscillator and laser processing apparatus. <P>SOLUTION: A plurality of LD bars 2 are soldered to a plurality of heat sinks 1 provided with a refrigerant channel 1a, respectively, and cooling the LD bars 2 individually. The heat sink 1 is fixed to a manifold 3 provided with supply channels 6a-6f having a different conduction cross-sectional area of refrigerant 13 for respective fixing parts 3a-3f. A heat sink 1 mounting an LD bar 2 having an oscillation wavelength shifted to the short wavelength side is fixed to the fixing part 3f provided with the supply channel 6f having a small conduction cross-sectional area, and a heat sink 1 fixed with an LD bar 2 having an oscillation wavelength shifted to the long wavelength side is fixed to the fixing part 3a provided with the supply channel 6a having a large conduction cross-sectional area. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser diode array, a laser oscillator, and a laser processing apparatus, and more particularly, to a laser diode array on which a plurality of laser diode elements are mounted, a laser oscillator using the laser diode array, and a laser processing apparatus.

  A laser diode (hereinafter referred to as LD) has high luminous efficiency and a narrow oscillation spectrum, and thus has extremely excellent characteristics as a pumping light source, and is used as a pumping light source for a solid-state laser such as an Nd: YAG laser. Widely used. Recently, as the output of solid-state laser oscillators has increased, the excitation LD has also adopted an array structure in which a plurality of LDs are arranged in a straight line or a stack structure in which a plurality of LDs are stacked.

  In general, an LD bar in which LDs are integrated is used as an excitation light source for a high-power solid-state laser, and the LD bar generates heat equal to or higher than its output. When the temperature of the LD bar rises, problems such as a decrease in durability and a shift in the oscillation wavelength occur. Therefore, a high-power LD bar prevents a temperature rise by attaching a heat sink (see Patent Document 1). FIG. 7 is an exploded perspective view schematically showing an example of a conventional LD array. As shown in FIG. 7, in the conventional LD array 20, for example, a plurality of heat sinks 21 on which LD bars 22 are individually mounted are mounted on a manifold 23. A cover 28 is disposed on these, and is screwed to the manifold 23 by screws 29. The manifold 23 is provided with a supply channel 26 for supplying a refrigerant to a refrigerant channel formed in the heat sink 21 and a discharge channel 27 for discharging the refrigerant from the refrigerant channel for each mounting portion of the heat sink 21. ing.

  In such a conventional LD array 20, since the heat sink 21 is a negative electrode, the positive electrode 24 provided on the upper surface of the LD bar 22 is adjacent to the heat sink 21 on which the LD bar 22 is mounted. Are connected to each other by a crossing electrode 25, whereby a plurality of LD bars 22 are connected in series.

  Usually, the LD bar has a variation of 4 to 5 nm in the oscillation wavelength, and the oscillation wavelength may change when the LD bar is mounted on the heat sink. For this reason, in the conventional LD array, the oscillation wavelength varies substantially by about 6 nm. On the other hand, a solid laser medium such as an Nd: YAG laser has an absorption spectrum width of about 2 to 3 nm. Therefore, in an LD array used as an excitation light source for a high-power laser oscillator, in the assembly process, the oscillation wavelength of the LD bar is measured while mounted on a heat sink, and the absorption spectrum of the solid-state laser medium is determined by the oscillation wavelength. We sort out what is within range and what is not. However, in the conventional LD array, the yield in this sorting operation is low, which is a factor that increases the manufacturing cost.

  Therefore, in order to improve the yield of the LD array, a method of adjusting the oscillation wavelength using the temperature dependence of the oscillation wavelength of the LD bar has been proposed (see, for example, Patent Documents 2 to 4). In the LD-excited solid-state laser device described in Patent Document 2, in the LD array in which the LD bar is mounted on the heat sink, the thermal resistance is changed by changing the temperature of the refrigerant of the heat sink. The oscillation wavelength is adjusted by changing. The LD-pumped solid-state laser device described in Patent Document 3 changes its thermal resistance by changing the thickness of an intermediate inclusion such as a submount provided between the heat sink and the LD. The oscillation wavelength is adjusted by changing the temperature. Further, the LD-excited solid-state laser device described in Patent Document 4 is provided with a heat sink for each LD bar, and a refrigerant is provided for each heat sink so that the oscillation wavelength of each LD bar is within the range of the absorption wavelength of the laser medium. Control means for adjusting the temperature and flow rate of the gas is provided. As a result, the oscillation wavelength is adjusted for each LD bar, and the oscillation wavelengths of a plurality of LD bars are aligned to improve the laser excitation efficiency.

JP-A-9-181376 Japanese Patent Laid-Open No. 5-211361 JP 11-103132 A JP-A-10-294513

  However, the conventional techniques described above have the following problems. First, the LD-pumped solid-state laser devices described in Patent Documents 2 and 3 must accurately control the heat resistance value of the heat sink or the intermediate inclusion between the heat sink and the LD bar, but the adjustment work is difficult. There is a problem that productivity is poor. In addition, when adjusting the temperature of the LD bar by changing the thermal resistance value of the intermediate inclusion, the LD bar must be selected according to the oscillation wavelength before being mounted on the heat sink, but the LD bar is usually formed of GaAs or the like. Even a large one is about 10 mm long, 1 mm wide, and about 0.1 mm thick, so it is brittle and easily broken. For this reason, the LD bar is difficult to handle, and there is a problem that the sorting operation in the state of the LD bar is very laborious.

  Furthermore, the LD-excited solid-state laser device described in Patent Document 4 requires means for controlling the flow rate and temperature of the refrigerant for each heat sink, and if there are as many valves and temperature sensors as the number of mounted LD bars, However, there is a problem that the system configuration becomes large. In particular, in a high-power LD array, hundreds of LD bars may be mounted, and it is difficult to provide valves or the like for all of them.

  The present invention has been made in view of such problems, and can improve the yield in the LD bar sorting operation and improve the laser excitation efficiency without introducing a large-scale system. An object is to provide a laser diode array, a laser oscillator, and a laser processing apparatus.

  The laser diode array according to the first invention of the present application includes a plurality of laser diodes, a plurality of heat sinks each provided with a coolant flow path for cooling the laser diodes individually, and a mounting portion to which the heat sinks are mounted for each heat sink. A supply channel that supplies the refrigerant to the refrigerant channel is formed for each mounting portion, and the supply channel of the manifold has a flow cross-sectional area of the refrigerant of 1 or The refrigerant is supplied at different flow rates to the refrigerant flow path of the heat sink mounted on the mounting section, which is different for each of the plurality of mounting sections and has a supply flow path having a different flow cross-sectional area.

  In the present invention, since the refrigerant can be supplied at different flow rates for each heat sink, the cooling efficiency can be changed for each LD. This makes it possible to use LDs that could not be used because the oscillation frequency is out of the range of the absorption spectrum of the solid-state laser medium, so that it is possible to greatly improve the yield in the LD selection operation. it can. In addition, since the intensity of the oscillation spectrum can be narrowed and increased as compared with the conventional LD array, the laser excitation efficiency can be improved. Furthermore, this LD array adjusts the flow velocity of the refrigerant flowing through the refrigerant flow path of each heat sink by changing the flow cross-sectional area of the supply flow path for supplying the refrigerant to each heat sink. As in the LD-excited solid-state laser device described in 4, the laser excitation efficiency can be improved without introducing a large-scale control means.

  In the laser diode array, for example, a heat sink of a laser diode whose oscillation wavelength is shifted to a shorter wavelength side than a desired value is mounted on a mounting portion having a supply channel having a small flow cross-sectional area, and the oscillation wavelength is The heat sink of the laser diode shifted to the longer wavelength side than the desired value is mounted on a mounting portion having a supply channel having a large flow cross-sectional area. In addition, a reducer that adjusts the flow cross-sectional area may be inserted into the supply flow path.

  The laser oscillator according to the second invention of the present application is mounted with the above-described laser diode array, and is characterized in that the solid-state laser is excited using this laser diode array as a light source.

  A laser processing apparatus according to the third invention of the present application has the above-described laser oscillator, and irradiates a workpiece with laser light emitted from the laser oscillator directly or via an optical fiber.

  According to the present invention, since the range of usable oscillation wavelengths can be expanded by setting the flow rate of the refrigerant according to the oscillation wavelength of the LD mounted on the heat sink, the yield in the LD sorting operation is greatly increased. In addition to improving the excitation efficiency of the laser, it is possible to increase the intensity by narrowing the width of the oscillation spectrum compared to the conventional LD array. Further, the LD array of the present invention adjusts the flow velocity of the refrigerant flowing through the refrigerant flow path of each heat sink by changing the flow cross-sectional area of the supply flow path for supplying the refrigerant to each heat sink. The laser excitation efficiency can be improved without introducing a system.

  Hereinafter, a laser diode array according to a first embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is an exploded perspective view schematically showing the LD array of this embodiment, and FIG. 2 is a partially sectional exploded perspective view showing the LD bar, heat sink and manifold shown in FIG. As shown in FIG. 1, in the LD array 10 of this embodiment, an LD bar 2 in which LD elements are integrated is mounted on a microchannel heat sink 1 that individually cools the LD bar 2. A plurality of heat sinks 1 on which LD bars 2 are mounted are mounted in a row on the manifold 3, a cover 11 is disposed so as to cover them, and is fixed to the manifold 3 with screws 12. Further, in the LD array 10, the positive electrode 9 is provided on the surface of the LD bar 2, and the heat sink 1 serves as a negative electrode. For this reason, the positive electrode 9 of the LD bar 2 and the heat sink 1 adjacent to the heat sink 1 on which the LD bar 2 is mounted are connected by the crossing electrode 8, whereby a plurality of LD bars are connected in series. ing. In addition, it is preferable that the manifold 3 and the cover 11 are formed with resin-type materials, such as polyether ether ketone, from an insulating point. Hereinafter, the heat sink 1, the LD bar 2, and the manifold 3 in the LD array 10 of the present embodiment will be described in detail.

  As shown in FIG. 2, the LD bar 2 is disposed along the short side of the upper surface of the heat sink 1 so that its longitudinal direction is perpendicular to the longitudinal direction of the heat sink 1, and is soldered onto the heat sink 1. ing. Further, a groove extending in the longitudinal direction is formed on the lower surface of the heat sink 1, and this groove becomes the refrigerant flow path 1a.

  The heat sink 1 on which the LD bar 2 is mounted is mounted in a row on concave mounting portions 3 a to 3 f provided on the upper surface of the manifold 3. The manifold 3 has supply channels 6a to 6f for supplying the refrigerant 13 injected from the introduction port 4 to the heat sinks 1 for each of the mounting portions 3a to 3f, and the refrigerant discharged from the heat sinks 1 to the discharge ports. The discharge channels 7 a to 7 f that lead to 5 are formed. The supply flow paths 6a to 6f and the discharge flow paths 7a to 7f are joined to each other and then connected to the introduction port 4 and the discharge port 5. In the LD array 10 of the present embodiment, for example, the introduction port 4 is formed on one surface perpendicular to the longitudinal direction of the manifold 3 and the discharge port 5 is formed on the other surface so as not to face each other. Has been. The diameters of the supply flow paths 6a to 6f and the discharge flow paths 7a to 7f, that is, the cross-sectional areas of the supply flow paths 6a to 6f and the discharge flow paths 7a to 7f are relatively large so as to approach the discharge port 5. Is changing. Therefore, the flow cross-sectional areas of the supply flow path 6f and the discharge flow path 7f on the introduction port 4 side are the smallest, and the flow cross-sectional areas of the supply flow path 6a and the discharge flow path 7a on the discharge port 5 side are the largest. In the LD array 10 of the present embodiment, the flow cross-sectional areas of the supply flow path and the discharge flow path provided in the same mounting portion are the same.

  Further, in the LD array 10 of the present embodiment, the heat sinks 1 are arranged in parallel to each other so that the longitudinal direction thereof is perpendicular to the longitudinal direction of the manifold 3. Accordingly, the LD bars 2 are arranged in a line with their longitudinal directions aligned in a direction parallel to the longitudinal direction of the manifold 3.

  Next, the operation of the LD array 10 of this embodiment will be described. The LD array 10 is injected with a coolant 13 such as water from the inlet 4. The refrigerant 13 flows to the refrigerant flow path 1a of each heat sink 1 via the supply flow paths 6a to 6f, and is further discharged from the discharge port 5 via the discharge flow paths 7a to 7f. At this time, the flow rate of the refrigerant 13 flowing through the refrigerant flow path 1a of the heat sink 1 changes according to the flow cross-sectional areas of the supply flow paths 6a to 6f that supply the refrigerant to the refrigerant flow path 1a. Specifically, when the refrigerant 13 is injected from the introduction port 4 at a constant flow rate, the refrigerant flow path 1a of the heat sink 1 mounted in the mounting portion 3a in which the supply flow path 6a having the largest flow cross-sectional area is formed. The flow velocity in the refrigerant flow path 1a of the heat sink 1 mounted on the mounting portion 3f in which the supply flow path 6f having the smallest flow cross-sectional area is formed is the slowest. That is, the heat sink 1 attached to the attachment portion 3a has the highest cooling efficiency, and the heat sink 1 attached to the attachment portion 3f has the lowest cooling efficiency.

  FIG. 3 is a graph showing the relationship between the oscillation frequency of the LD bar 2 mounted on the heat sink 1 and the refrigerant temperature, with the horizontal axis representing the refrigerant temperature and the vertical axis representing the oscillation wavelength of the LD bar 2. . FIG. 4 is a graph showing the relationship between the oscillation frequency of the LD bar 2 mounted on the heat sink 1 and the refrigerant flow rate, with the horizontal axis representing the refrigerant flow velocity and the vertical axis representing the oscillation wavelength of the LD bar 2. It is. Further, FIG. 5 is a graph showing the oscillation spectrum of the LD bar and the LD array, with the horizontal axis representing the oscillation wavelength and the vertical axis representing the intensity. As shown in FIG. 3, when the temperature of the LD bar 2 changes by 1 ° C., the oscillation frequency changes by about 0.2 nm. Therefore, by changing the temperature of the LD bar 2 by about 10 ° C., the oscillation frequency can be shifted by about 2 nm at the maximum. Further, as shown in FIG. 4, when the flow rate of the refrigerant is changed from 0.1 liter / minute to 0.7 liter / minute, the oscillation frequency of the LD bar 2 is changed from 807.5 nm to 805.6 nm to about 1.9 nm. shift.

  Therefore, in the LD array 10 of the present embodiment, for example, when the flow rate of the refrigerant is 0.4 liter / min, the LD bar No. 1 whose center wavelength of the oscillation spectrum is 805.8 nm is used. The heat sink on which A is mounted is disposed in the mounting portion 3f where the supply flow path 6f having the smallest flow cross-sectional area is formed, and the center wavelength is 807.2 nm when the flow rate of the refrigerant is 0.4 liter / min. LD bar No. The heat sink on which B is mounted is mounted on the mounting portion 3a where the supply channel 6a having the largest flow cross-sectional area is formed. As a result, the LD bar No. The flow rate of the refrigerant flowing through the heat sink on which A is mounted is 0.1 liter / min. The flow rate of the refrigerant flowing through the heat sink on which B is mounted is 0.7 liter / min. In this way, by differentiating the flow rate of the refrigerant 13 flowing through the heat sink 1 in accordance with the center wavelength of the oscillation spectrum of the LD bar 2, the LD bar No. A and LD bar no. The center wavelength of the oscillation spectrum of B can be aligned to 806.5 nm. As a result, as shown in FIG. A oscillation spectrum and LD bar no. The peak intensity can be increased without widening the combined spectrum with the oscillation spectrum of B. On the other hand, LD bar No. A and LD bar no. When B is mounted on the same array and the flow rates of the refrigerant flowing through the respective heat sinks are made equal as in the conventional case, the LD bar No. A oscillation spectrum and LD bar no. The combined spectrum with the oscillation spectrum of B does not have a high peak intensity but has a wider width.

  As described above, the LD array 10 of the present embodiment controls the oscillation wavelength of the LD bar 2 by using the oscillation wavelength temperature dependency of the LD bar 2 and the refrigerant flow rate dependency of the thermal resistance of the heat sink 1. Can do. Specifically, an LD bar whose oscillation wavelength is shifted to the shorter wavelength side than the absorption spectrum of the solid-state laser medium is placed on a water channel where the flow rate of the refrigerant is slow, and the oscillation wavelength is longer than the absorption spectrum of the solid-state laser medium. The LD bar is shifted to the water channel where the flow rate of the refrigerant is high. As a result, the oscillation wavelength of each LD bar can be changed to be within the range of the absorption spectrum of the solid-state laser medium.

  Further, the LD-excited solid-state laser device described in Patent Document 4 requires a large-scale refrigerant control means in which a valve is provided for each heat sink and the flow rate of the refrigerant flowing through each supply channel is controlled by this valve. However, in the LD array 10 of the present embodiment, the refrigerant is injected from the introduction port at a constant flow rate, and the flow cross-sectional area of the refrigerant in the supply flow path for supplying the refrigerant to each heat sink is changed, so that the heat sink Since the flow rate of the refrigerant flowing through the refrigerant flow path 1a is adjusted, the flow rate of the refrigerant can be adjusted with a simple configuration.

  Furthermore, when manufacturing the LD array 10 of the present embodiment, the LD bar 2 is mounted on the heat sink 1, and after the positive electrode 9 is attached to each LD bar 2, the oscillation wavelength of each LD bar 2 is measured. Whether or not the LD bar 2 can be used is selected based on the oscillation wavelength, and only the LD bar 2 determined to have the oscillation wavelength within a predetermined range is mounted on the manifold 3. Thus, in this embodiment, not the state of the LD bar 2 (vertical 10 mm, horizontal 1 mm, thickness 0.1 mm), but the LD bar 2 is mounted on the heat sink 1 and the positive electrode 9 is also attached. Since the sorting operation can be performed at a length of about 12 mm, a width of 20 mm, and a thickness of about 5 mm, the workability in the manufacturing process is superior to the LD-excited solid-state laser devices described in Patent Documents 2 and 3 above. .

  FIG. 6 shows a three-dimensional relationship between the oscillation spectrum of the LD bar and the flow rate of the refrigerant, with the oscillation wavelength on the first axis, the intensity on the second axis, and the flow rate of the refrigerant on the third axis. FIG. As shown in FIG. 6, when the coolant is flowed at a predetermined flow rate, the center wavelength is within the range of the absorption spectrum of the solid laser medium. Although the L2 and L3 LD bars, when the flow rate of the refrigerant is made lower than the predetermined flow rate, no. When the LD bars L2 to L4 are within the range of the absorption spectrum of the solid-state laser medium and the flow rate of the refrigerant is higher than a predetermined flow rate, L 3 to 5 LD bars can be used. In the conventional LD array, when there are six LD bars having different oscillation wavelengths as shown in FIG. Although only L3 and L4 LD bars could be used, in the LD array 10 of the present embodiment, the flow rate of the refrigerant flowing through the heat sink 1 is different for each mounting portion of the manifold 3, and in a single LD array, the flow rate is higher than a predetermined flow rate. Since there are a mounting portion where the flow rate of the refrigerant is fast and a slow mounting portion, the range of usable oscillation wavelengths is widened. Two to five LD bars can be used. As a result, the LD bars (No. L2 and No. L5) having an oscillation wavelength that cannot be used in the conventional LD array can be used, thereby improving the yield.

  However, if the wavelength selection range is set wider, the yield in the selection operation is further improved, but the width of the combined spectrum of the LD array is increased and the excitation efficiency is lowered. For this reason, in the LD array of this embodiment, the wavelength selection range is set to be narrow when the excitation efficiency is to be further improved, and the wavelength selection range is set to be wide when the yield is to be further improved. As a result, when the wavelength selection range is set narrow, the yield is only slightly improved over the conventional LD array, but the excitation efficiency can be greatly improved. On the other hand, when the wavelength selection range is set wide, the excitation efficiency is only slightly improved compared to the conventional LD array, but the yield can be greatly improved.

  As described above, in the LD array 10 of the present embodiment, the flow rate of the refrigerant flowing to the heat sink is adjusted by relatively changing the flow cross-sectional area of the supply channel that supplies the refrigerant to each heat sink. The oscillation wavelength of the LD array can be easily adjusted within the range of the absorption spectrum of the solid-state laser medium, and the yield in the LD bar sorting operation can be greatly improved as compared with the prior art. In addition, since the spectrum width of the LD array can be narrower than that of the conventional LD array and the intensity can be improved, the excitation efficiency of the laser can be improved.

  In the LD array of this embodiment, the flow rate of the refrigerant flowing through each heat sink is changed by providing supply passages having different flow cross sections in the manifold 3, but the present invention is limited to this. Instead, for example, by inserting reducers having different inner diameters into a plurality of supply flow paths having the same flow cross-sectional area, the flow cross-sectional areas of the respective supply flow paths can be adjusted.

  In the LD array of this embodiment, the LD bar is mounted on the water-cooled microchannel heat sink. However, the present invention is not limited to this, and various heat sinks such as an air-cooled heat sink can be used. Can be used.

  Furthermore, in the LD array of the present embodiment, the LD bar is directly soldered to the heat sink, but the present invention is not limited to this, and between the LD bar and the heat sink, Mo, CuW alloy and A plate-like member made of a material having a thermal property close to that of the LD bar, such as a CoNi alloy, that is, a submount may be disposed.

  Next, a laser oscillator according to a second embodiment of the invention will be described. The laser oscillator of this embodiment is an LD-pumped solid-state laser oscillator on which the LD array 10 of the first embodiment described above is mounted, and pumps a solid-state laser such as an Nd: YAG laser by the pump light generated by the LD array 10. This is a device that oscillates laser light. Since the laser oscillator of the present embodiment uses the LD array 10 of the first embodiment described above as an excitation light source, the oscillation efficiency is superior to an LD excitation laser oscillator using a conventional LD array.

  Next, a laser processing apparatus according to the third embodiment of the present invention will be described. The laser processing apparatus of the present embodiment uses the laser oscillator of the second embodiment described above, and irradiates the workpiece with the laser beam emitted from the laser oscillator, either directly or via an optical fiber. Is a device for processing. Since the laser processing apparatus according to the present embodiment uses a laser oscillator including the LD array 10 according to the first embodiment described above as an excitation light source, laser processing can be performed more efficiently than a conventional laser processing apparatus. .

1 is an exploded perspective view schematically showing an LD array of a first embodiment of the present invention. It is a partial cross section exploded perspective view showing LD bar, heat sink, and manifold of LD array of a 1st embodiment of the present invention. FIG. 5 is a graph showing the relationship between the oscillation frequency of the LD bar 2 mounted on the heat sink 1 and the refrigerant temperature, with the horizontal axis representing the refrigerant temperature and the vertical axis representing the oscillation wavelength of the LD bar 2. FIG. 4 is a graph showing the relationship between the oscillation frequency of the LD bar 2 mounted on the heat sink 1 and the refrigerant flow rate, with the horizontal axis representing the refrigerant flow rate and the vertical axis representing the LD bar 2 oscillation wavelength. It is a graph which shows the oscillation spectrum of LD bar | burr and LD array, taking an oscillation wavelength on a horizontal axis and taking an intensity | strength on a vertical axis | shaft. A three-dimensional graph showing the relationship between the oscillation spectrum of the LD bar and the flow rate of the refrigerant, with the oscillation wavelength on the first axis, the intensity on the second axis, and the flow rate of the refrigerant on the third axis. is there. It is a disassembled perspective view which shows an example of the conventional LD array typically.

Explanation of symbols

Heat sink 1a; Refrigerant flow path 2, 22; LD bar 3, 23; Manifold 3a-3f; Mounting part 4; Inlet 5; Discharge 6a-6f, 26; Supply flow path 7a-7f, 27; Discharge flow path 8, 25; Transition electrode 9, 24; Positive electrode 10, 20; LD array 11, 28; Cover 12, 29; Screw 13;

Claims (5)

A plurality of laser diodes, a plurality of heat sinks that are provided with a refrigerant flow path and individually cool the laser diode, and a mounting portion to which the heat sink is attached are provided for each heat sink, and supply the refrigerant to the refrigerant flow path. A supply channel for each mounting portion, and the supply flow channel of the manifold has a flow cross-sectional area of the refrigerant that is different for each of the one or more mounting portions, and the flow passage A laser diode array, wherein a coolant is supplied at different flow rates to a coolant channel of a heat sink mounted on a mounting portion in which supply channels having different cross-sectional areas are formed. The heat sink of the laser diode whose oscillation wavelength is shifted to the shorter wavelength side than the desired value is installed in a mounting part having a supply channel with a small flow cross-sectional area, and the oscillation wavelength is shifted to the longer wavelength side than the desired value. 2. The laser diode array according to claim 1, wherein the heat sink of the laser diode is mounted on a mounting portion having a supply flow path having a large flow cross-sectional area. The laser diode array according to claim 1 or 2, wherein a reducer for adjusting a flow cross-sectional area is inserted into the supply flow path. 4. A laser oscillator, wherein the laser diode array according to claim 1 is mounted, and a solid-state laser is excited by using the laser diode array as a light source. A laser processing apparatus comprising the laser oscillator according to claim 4, wherein the workpiece is irradiated with laser light emitted from the laser oscillator directly or via an optical fiber.

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