JP2014154851A - Semiconductor laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit temperature variations of a substrate on which multiple semiconductor laser diodes are disposed, thereby inhibiting deformation of the substrate.SOLUTION: A semiconductor laser device 100 includes: a semiconductor laser unit 110 where a semiconductor laser diode line is formed on a surface of a sub-mount 112; and a support member 120 which supports the sub-mount 112. In the support member 120, a cooling passage 122 extending along the semiconductor laser diode line is formed.

Description

  The present invention relates to a semiconductor laser device including a semiconductor laser unit in which a semiconductor laser diode array is formed.

  Conventionally, in order to obtain a high-power laser beam, a plurality of semiconductor laser diodes are stacked (stacked), and a stack configured to multiplex a plurality of laser beams output from the plurality of semiconductor laser diodes A type laser is known (see, for example, Patent Document 1 below).

  However, it is difficult for the stack type laser to narrow the interval between a plurality of laser beams because of its structure. For this reason, the stacked laser cannot increase the energy density of a plurality of laser beams, and it is difficult to obtain a higher-luminance output beam such as the excitation light of a fiber laser.

  Therefore, conventionally, in order to obtain a higher-luminance output beam, a semiconductor laser device in which a plurality of semiconductor laser diode chips and a plurality of microlenses are arranged on the surface of a plate-like submount has been used. According to this semiconductor laser device, after collimating a plurality of laser beams emitted from a plurality of semiconductor laser diode chips by a plurality of microlenses, the plurality of laser beams are closely aligned, and further, the plurality of laser beams By focusing the light beam with a condenser lens, an output beam with higher brightness can be obtained.

  In such a semiconductor laser device, in order to efficiently obtain a high-brightness output beam, the position and direction of each component on the submount are precisely adjusted, so that each of the emission positions of the plurality of laser beams is It is necessary to improve the accuracy of the propagation direction. However, such a semiconductor laser device may be affected by heat generated by a plurality of semiconductor laser diodes, and the submount may be distorted or warped. If the submount is distorted or warped, the positions and orientations of the constituent members are changed, and the accuracy of the laser beam emission position and propagation direction is reduced.

  Therefore, a semiconductor laser device having a cooling function has been devised so that such a problem does not occur. For example, Patent Document 2 below discloses a semiconductor laser device configured by laminating a plurality of semiconductor laser units. In the semiconductor laser device, each semiconductor laser unit has a plate-like and liquid-cooled type. A semiconductor laser module is provided on the upper surface side of the heat sink.

JP-A-6-283807 (publication date: October 7, 1994) JP 2012-89584 A (publication date: May 1, 2012)

  However, since the semiconductor laser device of Patent Document 2 cannot effectively cool the heat generated by the semiconductor laser diode while using a liquid-cooled heat sink, there is a problem of suppressing the heat sink warpage. It cannot be solved. For this reason, the semiconductor laser device of the above-mentioned patent document 2 is provided with a molybdenum reinforcing body on the back side of each semiconductor laser module so that the heat sink is not warped, thereby improving the overall rigidity.

  In particular, the semiconductor laser device disclosed in Patent Document 2 has a cooling path that penetrates in a direction perpendicular to the surface of the semiconductor laser unit on which a plurality of semiconductor laser modules are arranged (direction in which the semiconductor laser units are stacked). The structure which extends is adopted. For this reason, in the heat sink in which the semiconductor laser module is arranged, the cooling effect varies from part to part according to the distance from the cooling path, and therefore, temperature variation occurs from part to part of the heat sink. In the semiconductor laser module, such temperature variations cause distortion and deformation in the heat sink in which the semiconductor laser module is disposed, thereby reducing the accuracy of the emission position and propagation direction of the laser light emitted from the semiconductor laser module. It will be.

  The present invention has been made in view of such problems, and an object of the present invention is to prevent deformation such as distortion and warpage of the substrate by suppressing temperature variations in the substrate on which a plurality of semiconductor laser diodes are arranged. It is to realize a semiconductor laser device capable of suppressing the above.

  In order to solve the above-described problems, a semiconductor laser device according to the present invention includes a semiconductor laser unit in which a semiconductor laser diode array is formed on a surface of a substrate, and a support member that supports the substrate, and the support member Is characterized in that a cooling path extending along the semiconductor laser diode array is formed.

  According to the semiconductor laser device, since the cooling path is formed along the semiconductor laser diode array, a plurality of laser diodes can be uniformly cooled. Therefore, the temperature distribution for each laser diode unit on the substrate is the same. As a result, the semiconductor laser device can suppress distortion and warpage of the substrate due to variations in temperature distribution for each laser diode unit. Therefore, the semiconductor laser device can improve the accuracy of the emission positions and propagation directions of the plurality of laser beams, and as a result, the output beam can be increased in output and brightness. In particular, a configuration in which the end of the substrate in the vicinity of the semiconductor laser diode array is held by a support member may be employed, and in this case, the heat generated from the semiconductor laser diode array can be efficiently cooled by the support member. it can.

  In the semiconductor laser device, it is preferable that the shortest distances from the plurality of semiconductor laser diodes constituting the semiconductor laser diode array to the cooling path are equal to each other.

  According to the semiconductor laser device having the above configuration, the plurality of laser diodes can be cooled more uniformly, and therefore, the distortion and warpage of the substrate can be further suppressed.

  In the semiconductor laser device, it is preferable that the cooling path is formed on each of the front surface side of the substrate and the back surface side of the substrate so that the support member is symmetrical with respect to the substrate.

  According to the semiconductor laser device having the above-described configuration, the substrate can be uniformly cooled from both the front surface side and the back surface side, so that the temperature difference between the front surface side and the back surface side of the substrate is suppressed, and the substrate Can be prevented. Thereby, the semiconductor laser device having the above configuration can suppress the change in the propagation direction of the plurality of laser beams due to the warp of the substrate. Therefore, the semiconductor laser device can improve the accuracy of the emission positions and propagation directions of the plurality of laser beams, and as a result, the output beam can be increased in output and brightness.

  The semiconductor laser device includes a plurality of the semiconductor laser units stacked on each other, the support member supports an end of each of the plurality of semiconductor laser units, and the support member includes each of the plurality of substrates. On the other hand, it is preferable that the cooling path is formed on each of the front surface side of the substrate and the back surface side of the substrate so as to be front-back symmetrical.

  According to the semiconductor laser device configured as described above, it is possible to prevent the substrate from warping in each of the plurality of semiconductor laser units.

  In the semiconductor laser device, the support member functions as a cooling path on the back surface side with respect to the upper layer substrate between the upper layer substrate and the lower layer substrate, and also on the front surface side with respect to the lower layer substrate. It is preferable that the common cooling path that functions as the above is formed.

  According to the semiconductor laser device having the above configuration, both the upper layer substrate and the lower layer substrate can be cooled by one cooling path. That is, according to the semiconductor laser device having the above configuration, the number of cooling paths formed in the support member can be reduced, and therefore, for example, the manufacturing cost of the support member can be suppressed.

  In the semiconductor laser device, the substrate has a first portion that is a portion closer to the support member than the semiconductor laser diode array, than a second portion that is a portion opposite to the first portion. It is preferable to have a high thermal conductivity. In particular, in the semiconductor laser device, it is preferable that the substrate is provided with a heat pipe in the first portion.

  According to the semiconductor laser device having the above configuration, most of the heat generated by the semiconductor laser diode array in the substrate is transmitted to the support member side (first portion) having a low thermal resistance, and is actively dissipated by the support member. Will be. That is, according to the semiconductor laser device having the above configuration, the heat generated by the semiconductor laser diode array can be efficiently radiated.

  In the semiconductor laser device, it is preferable that the semiconductor diode array is composed of a plurality of semiconductor diodes having the same wavelength of emitted laser beam.

  According to the semiconductor laser device having the above configuration, the output beam can be further increased in output and brightness.

  In the semiconductor laser device, the plurality of semiconductor laser diode arrays corresponding to the plurality of semiconductor laser units preferably have different wavelengths of emitted laser beams.

  According to the semiconductor laser device having the above configuration, the output beam can be further increased in output and brightness.

  According to the present invention, it is possible to suppress a variation in temperature in a substrate on which a plurality of semiconductor laser diodes are arranged. Therefore, it is possible to realize a semiconductor laser device capable of suppressing deformation such as distortion and warpage of the substrate. can do.

It is a perspective view which shows the structure of the semiconductor laser apparatus which concerns on this embodiment. It is a side view which shows the structure of the semiconductor laser apparatus which concerns on this embodiment. It is AA sectional drawing of the semiconductor laser apparatus shown in FIG. It is a top view which shows the structure of the semiconductor laser unit which concerns on this embodiment. It is a side view which shows the structure of the semiconductor laser apparatus which concerns on the modification of this embodiment. An example of the flow of the coolant in the semiconductor laser device according to the present embodiment will be shown. It is a top view which shows the structure (modified example of FIG. 4) of the semiconductor laser unit which concerns on this embodiment. An example of the structure which carries out wavelength synthesis | combination of the laser beam of several layers in the semiconductor laser apparatus which concerns on this embodiment is shown. It is a side view which shows the structure (modified example of FIG. 2) of the semiconductor laser apparatus which concerns on this embodiment.

  A semiconductor laser device according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[Configuration of Semiconductor Laser Device 100]
First, the configuration of the semiconductor laser device 100 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing a configuration of a semiconductor laser device 100 according to the present embodiment. FIG. 2 is a side view showing the configuration of the semiconductor laser device 100 according to the present embodiment. 3 is a cross-sectional view of the semiconductor laser device 100 shown in FIG.

  The semiconductor laser device 100 is a device that emits a laser beam from each of a plurality of semiconductor laser diodes and outputs a laser beam with high output and high brightness by combining the plurality of laser beams. As shown in FIGS. 1 to 3, the semiconductor laser device 100 includes a plurality of semiconductor laser units 110 (semiconductor laser units 110-1 to 110-4) stacked in the vertical direction (z-axis direction).

  The semiconductor laser device 100 further includes a support member 120. The supporting member 120 is a rear end portion of each of the plurality of semiconductor laser units 110 (an end portion on the negative side of the x-axis, in the state where the plurality of semiconductor laser units 110 are stacked at equal intervals, and the semiconductor laser diode array) Support nearby edge). That is, the semiconductor laser device 100 employs a configuration in which the plurality of semiconductor laser units 110 are cantilevered by the support member 120.

  Specifically, a number of notches (four in FIGS. 1 to 3) corresponding to the semiconductor laser unit 110 are formed on the front surface (the surface on the x-axis positive side) of the support member 120. The notch has substantially the same shape as the shape of the rear end of the semiconductor laser unit 110 (submount 112). Then, the rear end portion of the corresponding semiconductor laser unit 110 (submount 112) is inserted into each notch, so that the support member 120 has a plurality of semiconductor laser units 110 in a predetermined posture. The rear end portions of the plurality of semiconductor laser units 110 are supported so as to be sandwiched while closely contacting along the semiconductor laser diode row.

  Further, each semiconductor laser unit 110 is fixed to the support member 120 by a fixing means (not shown) (for example, an adhesive, a screw, etc.), so that the support of the semiconductor laser unit 110 by the support member 120 is more reliable. It will be something. The support member 120 has a cooling path 122 through which a coolant flows, and also functions as a heat sink for cooling each semiconductor laser unit 110.

[Configuration of Semiconductor Laser Unit 110]
Next, the configuration of the semiconductor laser unit 110 will be described with reference to FIG. FIG. 4 is a top view showing the configuration of the semiconductor laser unit 110 according to the present embodiment. All of the four semiconductor laser units 110 (semiconductor laser units 110-1 to 110-4) included in the semiconductor laser device 100 have the same configuration as the semiconductor laser unit 110 shown in FIG.

(Semiconductor laser diode)
The semiconductor laser unit 110 includes a rectangular plate-shaped submount 112 (substrate) and semiconductor laser diodes (semiconductor laser diode chips) LD1 to LD10. Each of the semiconductor laser diodes LD1 to LD10 is formed on an independent chip. The semiconductor laser diodes LD1 to LD10 are arranged in a line on the surface of the submount 112 along the rear end portion of the submount 112 in a straight line at equal intervals in the y-axis direction in the figure. Has been. That is, the semiconductor laser diodes LD1 to LD10 form a semiconductor laser diode array on the surface of the submount 112.

  Each of the semiconductor laser diodes LD1 to LD10 is arranged on the surface of the submount 112 so that the active layer is parallel to the xy plane and the laser beam emission surface is directed in the positive x-axis direction. Yes. Thereby, the plurality of laser beams emitted from the semiconductor laser diodes LD1 to LD10 propagate on the surface of the submount 112 in parallel to the xy plane and in the positive x-axis direction. It will be. That is, the plurality of laser beams form a laser beam train that is equidistant and parallel on the surface of the submount 112.

(Light guide device)
The semiconductor laser unit 110 further includes F-axis collimating lenses FAC1 to FAC10, S-axis collimating lenses SAC1 to SAC10, and mirrors M1 to M10. That is, in the semiconductor laser unit 110, one F-axis collimating lens, one S-axis collimating lens, and one mirror are arranged in a straight line on the laser beam propagation path in order for one semiconductor laser diode. Has been. All of these members are installed on the surface of the submount 112 directly or via a mount (not shown). These members constitute a light guide device in the semiconductor laser unit 110. In this light guide device, the intervals between the plurality of laser beams propagating in the x-axis direction (first horizontal direction) emitted from the semiconductor laser diodes LD1 to LD10 are made closer, and the y-axis direction (second horizontal direction) ).

  The F-axis collimating lens FACi (i = 1 to an integer of 1 to 10) is for collimating the spread of the laser beam emitted from the semiconductor laser diode LDi (i = an integer of 1 to 10) in the F-axis direction. The S-axis collimating lens SACi (i = 1 to an integer of 1 to 10) is for collimating the spread in the S-axis direction of the laser beam emitted from the semiconductor laser diode LDi. The laser beam transmitted through the F-axis collimating lens FACi and the S-axis collimating lens SACi becomes a collimated beam whose propagation direction is converged in the positive x-axis direction and propagates to the mirror Mi. Note that when the spread of the laser beam emitted from the semiconductor laser diode LDi in the S-axis direction is sufficiently small, the S-axis collimating lens SACi may be omitted.

  The mirror Mi (i = 1 to an integer of 1 to 10) is for converting the propagation direction of the laser beam from the positive x-axis direction to the negative y-axis direction. Various conventionally known mirrors can be used as the mirror Mi, but a first mirror (so-called so-called mirror) that converts the propagation direction of the laser beam from the positive x-axis direction to the positive z-axis direction as necessary. And a second mirror (so-called “folding mirror”) that changes the propagation direction of the laser beam from the positive z-axis direction to the negative y-axis direction. preferable.

  Here, the positions of the mirrors M1 to M10 in the x-axis direction are separated from the emission direction (y-axis negative direction) of the plurality of laser beams (after the propagation direction is changed by the mirrors M1 to M10). In the direction approaching the semiconductor laser diode (the negative x-axis direction), it is shifted by a predetermined amount. Each shift amount is smaller than the interval between the plurality of laser beams (before the propagation direction is changed by the mirrors M1 to M10). As a result, the plurality of laser beams are emitted from the semiconductor laser unit 110 in an evenly spaced and more closely aligned state.

  The plurality of laser beams emitted from the semiconductor laser unit 110 are focused by one or a plurality of condensing lenses arranged on the optical path of the plurality of laser beams, and output as output beams. For example, in FIG. 4, as an example, a plurality (ten) of laser beams are focused on the incident end face of the optical fiber OF by the F-axis condenser lens FL and the S-axis condenser lens SL arranged on the optical path. Thus, it is shown that the laser beam (output beam) having high output and high brightness is incident on the optical fiber OF. Actually, a plurality (10 × 4 = 40) of laser beams output from the four semiconductor laser units 110 are focused on the incident end face of the optical fiber OF and are incident on the optical fiber OF. .

  Here, each of the four semiconductor laser units 110 preferably has the same wavelength of a plurality of laser beams propagating in the same semiconductor laser unit 110. Further, the four semiconductor laser units 110 preferably have different output beam wavelengths for each layer. That is, it is preferable that the laser beam incident into the optical fiber OF is a wavelength-synthesized one. Thereby, the semiconductor laser device 100 can increase the output beam and increase the brightness of the output beam.

  Each semiconductor laser unit 110 is adjusted to the support member 120 as shown in FIG. 1 after the positions and orientations of the constituent members arranged on the submount are precisely adjusted so as to obtain an optimum output beam. The laminated structure is formed together with other semiconductor laser units 110.

[Configuration of Cooling Path 122]
In the semiconductor laser device 100 of FIGS. 1 to 3, it should be noted that a plurality of cooling paths 122 (cooling paths 122-1 to 122-1) with respect to the support member 120 depending on the provision of the plurality of semiconductor laser units 110. 122-5) is formed. In particular, the plurality of cooling paths 122 have the following ingenuity regarding their arrangement.

  (Device 1) The support member 120 is provided with a cooling path 122 extending in the y-axis direction along the semiconductor laser diode array. As a result, the temperature in the y-axis direction of the submount 112 can be made uniform, so that the semiconductor laser device 100 of this embodiment can uniformly cool a plurality of laser diodes constituting the semiconductor laser diode array. . As a result, the semiconductor laser device 100 according to the present embodiment can suppress deformation such as distortion and warpage of the submount 112 caused by variations in the temperature of the submount 112 in the y-axis direction. It is possible to suppress a decrease in accuracy of the beam emission position and propagation direction.

  In particular, the cooling path 122 extends parallel to the semiconductor laser diode array. That is, the shortest distances from the plurality of semiconductor laser diodes constituting the semiconductor laser diode array to the cooling path 122 are equal to each other. Thereby, the semiconductor laser apparatus 100 of this embodiment can cool a some laser diode more uniformly.

  (Device 2) A cooling path 122 extending in the y-axis direction along the semiconductor laser diode array is formed in the support member 120 for each semiconductor laser diode array. Thereby, the semiconductor laser device 100 of the present embodiment can make the temperature in the y-axis direction uniform for each of the plurality of submounts 112. Therefore, the semiconductor laser device 100 of the present embodiment can suppress deformations such as distortion and warping of the submount 112 for each of the plurality of semiconductor laser units 110, and thus the emission positions and propagation of the plurality of laser beams can be suppressed. A decrease in direction accuracy can be suppressed.

  (Device 3) The support member 120 has a cooling path 122 on the front surface side of the submount 112 and a back surface of the submount 112 so as to be vertically (front and back) symmetrical with respect to each of the plurality of submounts 112. A cooling path 122 on the side is formed. Specifically, cooling paths 122-1 and 122-2 are formed vertically symmetrically with respect to the submount 112 of the semiconductor laser unit 110-1. Further, cooling paths 122-2 and 122-3 are formed vertically symmetrically with respect to the submount 112 of the semiconductor laser unit 110-2. Further, cooling paths 122-3 and 122-4 are formed symmetrically with respect to the submount 112 of the semiconductor laser unit 110-3. Further, cooling paths 122-4 and 122-5 are formed symmetrically with respect to the submount 112 of the semiconductor laser unit 110-4.

  As a result, the semiconductor laser device 100 of the present embodiment can cool each of the plurality of submounts 112 equally from both the front surface side and the back surface side. The temperature difference from the side can be suppressed, and the warpage of the submount 112 can be prevented. As a result, the semiconductor laser device 100 of this embodiment can suppress a decrease in accuracy of the emission positions and propagation directions of a plurality of laser beams due to warpage of the submount 112 in each semiconductor laser unit 110. A laser beam with high output and high brightness can be obtained.

  (Ingenuity point 4) In the support member 120, between the pair of upper and lower submounts 112, it functions as a cooling path 122 on the back surface side with respect to the upper submount 112 and as a cooling path on the front surface side with respect to the lower submount 112 A functioning common cooling path 122 is formed. That is, the semiconductor laser device 100 of the present embodiment is configured to cool the two submounts with one cooling path 122. Specifically, the cooling path 122-2 cools both the submount 112 of the semiconductor laser unit 110-1 and the submount 112 of the semiconductor laser unit 110-2. The cooling path 122-3 cools both the submount 112 of the semiconductor laser unit 110-2 and the submount 112 of the semiconductor laser unit 110-3. The cooling path 122-4 cools both the submount 112 of the semiconductor laser unit 110-3 and the submount 112 of the semiconductor laser unit 110-4.

  Thereby, the semiconductor laser device 100 of this embodiment can reduce the number of the cooling paths 122 between the submounts 112 and can easily form the cooling paths 122. For example, the support member 120 The manufacturing cost can be suppressed. Furthermore, by providing the common cooling path 122, the volume of the cooling path 122 between the submounts 112 can be increased, and thus the cooling effect can be enhanced.

  (Device 5) Since the semiconductor laser device 100 according to the present embodiment employs a configuration in which the rear end portion of each submount 112 is cantilevered, the laser diode is emitted from the semiconductor laser diode in any one of the submounts 112. Even when heat stress occurs, the stress can be released to the tip of the submount 112. For this reason, in the semiconductor laser device 100 of the present embodiment, deformation such as distortion and warpage of the submount 112 is less likely to occur.

[Modification]
Next, a modification of the semiconductor laser device 100 will be described with reference to FIG. FIG. 5 is a side view showing a configuration of a semiconductor laser device 100 according to a modification of the present embodiment.

  The semiconductor laser device 100 of the present modification (FIG. 5) is different from the semiconductor laser of FIG. 2 in that a heat pipe 118 (heat transfer member) is provided for each submount 112 of the plurality of semiconductor laser units 110. Different from the device 100.

  Specifically, in each of the plurality of submounts 112, the first portion, which is the portion closer to the support member 120 (x-axis negative side) than the semiconductor laser diode row, includes the submount as shown in FIG. A heat pipe 118 having a higher thermal conductivity than that of the mount 112 is embedded. Accordingly, in each of the plurality of submounts 112, the first portion has higher thermal conductivity than the second portion which is the portion on the opposite side (x-axis positive side) of the first portion. It has become a thing. The heat pipe 118 is made of a metal (for example, copper) and a cylindrical member in which a liquid (for example, alternative chlorofluorocarbon) is sealed. On the high temperature side, the heat pipe 118 generates heat as the liquid evaporates. In the low temperature side, the liquid vapor releases heat by agglomeration, thereby improving heat transfer efficiency.

  Thereby, in each of the plurality of submounts 112, most of the heat generated by the semiconductor laser diode array is transferred to the support member 120 side (first portion) having a low thermal resistance, and the support member 120 (specifically, Then, heat is positively dissipated by the cooling path 122) provided above and below the first portion. That is, the semiconductor laser device 100 of the present modification can efficiently dissipate the heat generated by the semiconductor laser diode array, and therefore deformations such as distortion and warping of the submount 112 due to the heat generation are caused in each layer. Can be suppressed.

  Further, in each of the plurality of submounts 112, the heat is less likely to be transmitted to the second part, which is the part on the laser beam emission side, so that the second part is caused by the heat. Distortion (especially, distortion caused by thermal interference between the stacked submounts 112) is less likely to occur. As a result, the semiconductor laser device 100 according to the present modification suppresses the positional deviation of each member (S-axis collimating lens and mirror) disposed in the second portion regardless of the optical path length from the semiconductor laser diode to the mirror. Therefore, it is possible to suppress a decrease in accuracy of the emission positions and propagation directions of the plurality of laser beams output from the plurality of semiconductor laser units 110.

  In addition, in this modification, although the heat pipe 118 was used as an example of a heat-transfer member, it is not restricted to this. That is, any heat transfer member may be used as long as it has a thermal conductivity higher than that of at least the submount 112. In the present modification, the heat conductivity of the first portion of the submount 112 is higher than that of the second portion by embedding a heat transfer member in the submount 112, but the present invention is not limited to this. That is, the thermal conductivity of the first portion of the submount 112 may be higher than that of the second portion without embedding the heat transfer member in the submount 112. For example, the thermal conductivity of the first part may be made higher than that of the second part by making the material of the first part different from the material of the second part.

[Example of coolant flow]
Next, an example of the flow of the coolant in the semiconductor laser device 100 will be described with reference to FIG. FIG. 6 shows an example of the flow of the coolant in the semiconductor laser device 100 according to the present embodiment.

  In the example shown in FIG. 6, the semiconductor laser device 100 further includes an injection pipe 602 and a discharge pipe 604. The injection pipe 602 is for feeding a coolant into the cooling path 122. The discharge pipe 604 is for discharging the coolant from the cooling path 122. As the injection pipe 602 and the discharge pipe 604, for example, a metal (for example, copper, aluminum), a resin, or the like is used. As the cooling liquid, for example, water, antifreeze liquid or the like is used.

  In the example shown in FIG. 6, the injection pipe 602 branches from one cooling path to five cooling paths. Each of the five cooling paths of the injection pipe 602 is connected to the end of the corresponding cooling path 122 on the injection side (the y-axis negative side in the figure). One cooling path of the injection pipe 602 is connected to, for example, a discharge port of a cooling pump (not shown).

  On the other hand, the discharge pipe 604 merges from five cooling paths into one cooling path. Each of the five cooling paths of the discharge pipe 604 is connected to the end of the corresponding cooling path 122 on the discharge side (y-axis positive side in the figure). One cooling path of the discharge pipe 604 is connected to the inlet of the cooling pump, for example.

  The connection method of the pipe (injection pipe 602 and discharge pipe 604) to the cooling path 122 is not particularly limited, and various conventionally known connection methods (for example, a cylindrical shape extending from the end of the cooling path 122) A method of inserting the pipe into the connector, or a method of fixing the pipe to the wall surface of the support member 120 in a state where the end of the cooling path 122 and the end of the pipe are in close contact with each other can be employed.

  In the semiconductor laser device 100 of FIG. 6, the coolant fed into the injection pipe 602 is branched into the injection pipe 602 and is sent into the respective cooling paths 122 (cooling paths 122-1 to 122-5). The coolant fed into each cooling path 122 passes through each cooling path 122 in parallel to the xy plane and along each semiconductor laser diode array. Then, the coolant that has passed through each cooling path 122 is sent into the discharge pipe 604, joined in the discharge pipe 604, and then discharged from the discharge pipe 604. The coolant discharged from the discharge pipe 604 is returned to the cooling pump, for example, and sent to the injection pipe 602 again.

  According to the configuration of FIG. 6, since the cooling liquid having substantially the same temperature is sent to each cooling path 122 (cooling paths 122-1 to 122-5), the surface side of each of the plurality of submounts 112 is provided. Further, cooling can be performed more evenly from both the rear surface side and the rear surface side. Therefore, in each semiconductor laser unit 110, since temperature variation of the submount 112 can be suppressed, deformation such as distortion and warpage of the submount 112 can be suppressed.

  Furthermore, according to the configuration of FIG. 6, a plurality of semiconductor laser units 110 (semiconductor laser units 110-1 to 110-4) can be cooled to the same extent, so that the temperature difference between the semiconductor laser units 110 (that is, , Variation in temperature in the z-axis direction). Therefore, it is possible to suppress variations in laser beam accuracy among the plurality of semiconductor laser devices 100.

[Example of configuration for wavelength synthesis of multiple layers of laser beams]
Next, with reference to FIGS. 7 and 8, an example of a configuration for combining the wavelengths of a plurality of laser beams in the semiconductor laser device 100 will be described.

  FIG. 7 is a top view showing the configuration of the semiconductor laser unit 110 according to this embodiment (modified example of FIG. 4).

  On the surface of the submount 112 shown in FIG. 7, a wavelength selection beam splitter 116 is disposed at a position on the optical path of a plurality of laser beams that are closely aligned by the mirrors M1 to M10. The wavelength selective beam splitter 116 reflects the laser beam incident from the side (y-axis positive direction) downward (z-axis negative direction). The wavelength selective beam splitter 116 further transmits the laser beam incident from above (z-axis positive direction) downward. Thereby, the wavelength selection beam splitter 116 can synthesize the wavelength of the laser beam of the layer and the laser beam of the upper layer, and can emit the wavelength-synthesized laser beam downward. Note that an antireflection film (not shown) for preventing the reflection of the laser beam is mounted on the side surface and the upper surface of the wavelength selection beam splitter 116.

  In the submount 112 of FIG. 7, a hole 114 is formed at a position below the wavelength selection beam splitter 116 (that is, a position in the propagation direction of the laser beam emitted from the wavelength selection beam splitter 116). As a result, the laser beam emitted downward from the wavelength selective beam splitter 116 can propagate to the back side of the submount 112 through the hole 114 without being blocked by the submount 112.

  FIG. 8 shows an example of a configuration for synthesizing wavelengths of a plurality of laser beams in the semiconductor laser device 100 according to the present embodiment. In FIG. 8, the propagation direction of the laser beam is indicated by an arrow. Further, in the semiconductor laser device 100 of FIG. 8, a plurality of laser beams in units of layers having different wavelengths are used. Further, each of the plurality of semiconductor laser units 110 is provided with a wavelength selective beam splitter 116 and a hole 114 similarly to the semiconductor laser unit 110 of FIG.

  In any of the semiconductor laser units 110, the laser beam of the layer is reflected downward by the wavelength selective beam splitter 116, and the laser beam of the layer higher than the layer is transmitted downward by the wavelength selective beam splitter 116. It is configured. That is, each of the semiconductor laser units 110 is configured to synthesize the wavelength of the laser beam of the layer and the laser beam of the upper layer by the wavelength selection beam splitter 116 and to emit the wavelength-synthesized laser beam downward. Yes.

  Accordingly, the semiconductor laser device 100 of FIG. 8 can synthesize a plurality of layers of laser beams having different wavelengths, and can emit a laser beam with higher brightness from the lowermost hole 114. It has become.

  Here, a specific example of wavelength synthesis by the semiconductor laser device 100 will be described. For example, the wavelength of the laser beam of each layer is set as follows.

First layer (semiconductor laser unit 110-1): λ1
Second layer (semiconductor laser unit 110-2): λ2
Third layer (semiconductor laser unit 110-3): λ3
Fourth layer (semiconductor laser unit 110-4): λ4
Then, the wavelength selective beam splitter 116 of each layer is configured as follows.

  First layer: Reflects a laser beam of wavelength λ1 incident from the side downward.

  Second layer: Reflects the laser beam with the wavelength λ2 incident from the side downward and transmits the laser beam with the wavelength λ1 incident from the upper side downward.

  Third layer: Reflects the laser beam of wavelength λ3 incident from the side downward and transmits the laser beams of wavelength λ1 and wavelength λ2 incident from above downward.

  Fourth layer: Reflects the laser beam of wavelength λ4 incident from the side downward and transmits the laser beams of wavelength λ1, wavelength λ2, and wavelength λ3 incident from above downward.

  As a result, the semiconductor laser device 100 of FIG. 8 synthesizes the wavelength λ1, the wavelength λ2, the wavelength λ3, and the wavelength λ4 of the laser beam, and thereby the high-intensity laser beam is emitted from the hole 114 in the bottom layer Can be emitted.

  In this example, the wavelength selection beam splitter is provided on the submount 112, but the wavelength selection beam splitter may be provided outside the submount 112. In this case, it is not necessary to form the holes in the submount 112.

  A mirror, a diffraction grating, or the like may be used instead of the wavelength selective beam splitter. When the wavelength selective beam splitter or the like is provided outside the submount 112, the wavelength selective beam splitter or the like may have a cantilever structure as with the submount 112.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

(Number of semiconductor laser units)
The semiconductor laser device 100 of this embodiment includes four semiconductor laser units 110 (semiconductor laser units 110-1 to 110-4), but is not limited thereto. That is, the semiconductor laser device 100 may include three or less semiconductor laser units 110, or may include four or more semiconductor laser units 110.

(About the number of semiconductor laser diodes)
In the semiconductor laser device 100 of the present embodiment, each semiconductor laser unit 110 includes ten semiconductor laser diodes, but is not limited thereto. That is, each semiconductor laser unit 110 may include nine or less semiconductor laser diodes, or may include eleven or more semiconductor laser diodes.

(About the arrangement and shape of the cooling path 122)
In the semiconductor laser device 100 of the present embodiment, the cooling path 122 to be formed in the support member 120 is vertically symmetrical with respect to the submount 112 and can be any one that extends along the semiconductor laser diode array. Such an arrangement / shape may be adopted.

  For example, in the semiconductor laser device 100 of this embodiment, in the support member 120, a single cooling path 122 shared by the upper submount 112 and the lower submount 112 is provided between the upper and lower submounts 112. However, the cooling path 122 for the upper submount 112 and the cooling path 122 for the upper submount 112 may be provided.

  In the semiconductor laser device 100 of the present embodiment, one cooling path 122 is provided for each of the front surface side and the back surface side of the submount 112, but a plurality of cooling paths 122 may be provided. .

  In the semiconductor laser device 100 of this embodiment, the plurality of cooling paths 122 (cooling paths 122-1 to 122-5) are independent of each other, but at least some of the cooling paths 122 have other cooling paths 122. And a continuous cooling path may be configured together with the other cooling path 122.

  In the semiconductor laser device 100 of this embodiment, since the semiconductor laser diode array is linear, the cooling path 122 is also configured to extend linearly. Here, the semiconductor laser diode array may have a state other than a linear shape (for example, an arc shape or a V shape). In this case, the cooling path 122 can be extended to the other state by extending along the semiconductor laser diode array.

  Further, in the semiconductor laser device 100 of the present embodiment, the support member 120 has a structure that supports the end of the submount 122 along the semiconductor laser diode row, but is cooled along at least the semiconductor laser diode row. Any other structure may be used as long as the path 122 extends.

  FIG. 9 is a side view showing the configuration of the semiconductor laser device 100 according to the present embodiment (modified example of FIG. 2). For example, as shown in FIG. 9, the support member 120 includes a plurality of plate-like portions 120A stacked on each other and a columnar portion 120B that cantilever-supports the plurality of plate-like portions 120A, and each plate-like portion 120A. A configuration in which the corresponding submount 112 is installed on the upper surface of the substrate may be adopted. Also in this case, as shown in FIG. 9, the cooling path 122 (in the example shown in FIG. 9, cooling paths 122-1 to 122-4) is formed in the support member 120 so as to extend along the semiconductor laser diode array. By doing so, temperature variations in the submount 112 can be suppressed. In the example shown in FIG. 9, the cooling path 122 is formed in the columnar part 120B, but the cooling path 122 may be formed in each plate-like part 120A.

  In the present embodiment, the “submount” is used as an example of the “substrate” of the present invention. However, the “substrate” of the present invention is not limited to this, and the “substrate” may be referred to as “mount”, for example. In general, the members on which the semiconductor laser diode array is formed are included.

  The present invention can be suitably used for a semiconductor laser device including a semiconductor laser unit in which a semiconductor laser diode array is formed. In particular, it can be suitably used for a semiconductor laser device in which a plurality of semiconductor laser units are stacked.

100 Semiconductor Laser Device 110 (110-1 to 110-4) Semiconductor Laser Unit 112 Submount (Substrate)
118 Heat pipe 120 Support member 122 (122-1 to 122-5) Cooling path 602 Injection pipe 604 Discharge pipe LD1 to LD10 Semiconductor laser diode FAC1 to FAC10 F axis collimating lens SAC1 to SAC10 S axis collimating lens M1 to M10 Mirror

Claims (9)

A semiconductor laser unit in which a semiconductor laser diode array is formed on the surface of the substrate;
A support member for supporting the substrate,
The support member is
A cooling path extending along the semiconductor laser diode array is formed. A semiconductor laser device, wherein: 2. The semiconductor laser device according to claim 1, wherein a shortest distance from each of the plurality of semiconductor laser diodes constituting the semiconductor laser diode array to the cooling path is equal to one another. The support member is
3. The semiconductor laser according to claim 1, wherein the cooling path is formed on each of a front surface side of the substrate and a back surface side of the substrate so as to be symmetric with respect to the substrate. 4. apparatus. A plurality of the semiconductor laser units stacked on each other;
The support member is
Supporting an end of each of the plurality of semiconductor laser units;
The support member is
The cooling path on the front surface side of the substrate and the cooling path on the back surface side of the substrate are respectively formed so as to be symmetric with respect to each of the plurality of substrates. The semiconductor laser device according to claim 3. The support member is
The common cooling path that functions as the cooling path on the back surface side with respect to the upper layer substrate and functions as the cooling path on the front surface side with respect to the lower layer substrate is formed between the upper layer substrate and the lower layer substrate. The semiconductor laser device according to claim 4, wherein the semiconductor laser device is provided. The substrate is
The first part, which is the part closer to the support member than the semiconductor laser diode array, has a higher thermal conductivity than the second part, which is the part opposite to the first part. A semiconductor laser device according to claim 4 or 5. The substrate is
The semiconductor laser device according to claim 6, wherein a heat pipe is provided in the first portion. The semiconductor laser device according to claim 4, wherein the semiconductor laser diode array includes a plurality of semiconductor diodes having the same wavelength of emitted laser beam. . The semiconductor laser device according to claim 8, wherein the plurality of semiconductor laser diode arrays corresponding to the plurality of semiconductor laser units have different wavelengths of emitted laser beams.

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