JP2022089985A - Semiconductor laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor laser device with a high coherence reduction effect inexpensively and easily.

SOLUTION: A semiconductor laser device comprises: a plate-like semiconductor laser chip 5 on which a plurality of light-emitting regions extending in a light travelling direction are arranged at an interval in a direction perpendicular to the travelling direction; a submount 3 bonded with the semiconductor laser chip 5; and a heat sink 2 bonded with a surface of the submount 3 opposite to a surface bonded with the semiconductor laser chip 5. A heat resistance of a heat transfer path connecting between each of the plurality of light-emitting regions and the heat sink 2 monotonously decreases or monotonously increases as it goes from one end side toward the other end side in the arrangement direction of the plurality of light-emitting regions.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present application relates to a semiconductor laser device.

In a device for displaying a color image such as a projector device and a projection television, a light source having three colors of R (red), G (green), and B (blue) is required as a light source. As this light source, a semiconductor laser device having high luminous efficiency may be used. Laser light has the feature of widening the reproduction color gamut due to its monochromaticity, but because it has the same phase, it has high coherence and causes the appearance of speckle patterns on the projection surface, so-called speckle noise. May become.

In order to reduce coherence, it is conceivable to simultaneously generate laser beams having different wavelengths so that they can be recognized by the naked eye as having the same color. Therefore, it is conceivable to apply the technique of a semiconductor laser device (see, for example, Patent Documents 1 and 2) in which a plurality of active layers having different specifications are formed on one substrate to generate laser light having different wavelengths. .. However, in order to form a plurality of active layers having different properties, the element forming process becomes complicated, and there is a concern that the cost increases and the yield deteriorates.

On the other hand, the active layers of the same specifications are arranged, and a heat sink using a material having a higher thermal conductivity is provided in the portion in contact with the active layers on both ends than in the portion in contact with the active layer on the central side in the arrangement direction. A semiconductor laser device has been proposed (see, for example, Patent Document 3). In this configuration, the element forming process is not complicated, and a temperature difference occurs between the active layer on the central side and the active layer on both ends during operation. Therefore, the active layer on the central side and the activity on both ends are active. Laser light having different wavelengths can be generated between the layers.

Japanese Unexamined Patent Publication No. 2004-47096 (paragraphs 0025 to 0034, FIGS. 3 to 6) JP-A-2007-95736 (paragraphs 0026 to 0037, FIGS. 1 to 4) Republished patent WO2015 / 063973 (paragraphs 0020 to 0030, FIGS. 3 to 5)

However, forming a member by combining materials having different thermal conductivity leads to an increase in cost. Alternatively, even if the members can be inexpensively formed of materials having different thermal conductivity, if the thermal conductivity is configured to be different between the center side and both end sides, the active layers at the same distance from the center are the same. It becomes the temperature and generates laser light of the same wavelength. That is, a part of the plurality of active layers generates laser light having the same wavelength, and the effect of reducing coherence is low.

The present application discloses a technique for solving the above-mentioned problems, and an object thereof is to obtain a semiconductor laser device having a high coherence reducing effect inexpensively and easily.

The semiconductor laser apparatus disclosed in the present application includes a plate-shaped semiconductor laser chip in which a plurality of light emitting regions extending along the traveling direction of light are arranged at intervals in a direction perpendicular to the traveling direction. A submount bonded to a semiconductor laser chip and a heat sink bonded to a surface of the submount opposite to the surface to which the semiconductor laser chip is bonded are provided, and each of the plurality of light emitting regions and the heat sink are provided. It is characterized in that the heat resistance of the heat transfer path to be connected is monotonically decreased or monotonically increased from one end side to the other end side in the arrangement direction of the plurality of light emitting regions.

According to the semiconductor laser device disclosed in the present application, since the temperature of each light emitting region changes along the arrangement direction, a semiconductor laser device having a high coherence reducing effect can be easily obtained inexpensively.

1A to 1C are a cross-sectional view perpendicular to the optical traveling direction of the semiconductor laser apparatus according to the first embodiment, a sectional view perpendicular to the optical traveling direction of the semiconductor laser chip, and in the plane facing the submount, respectively. It is a top view which shows the processing area. 2A and 2B show a cross-sectional view perpendicular to the optical traveling direction of the semiconductor laser chip constituting the semiconductor laser apparatus according to the modification of the first embodiment, and a processing region in the surface facing the submount, respectively. It is a plan view. 3A to 3C are a cross-sectional view perpendicular to the optical traveling direction of the semiconductor laser apparatus according to the second embodiment, a plan view showing a processing region in a plane facing the semiconductor laser chip of the submount, and optical traveling, respectively. It is a cross-sectional view perpendicular to a direction. 4A and 4B are a plan view showing a processing region in a plane facing the semiconductor laser chip of the submount constituting the semiconductor laser apparatus according to the modification of the second embodiment and a cross section perpendicular to the optical traveling direction, respectively. It is a figure. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on Embodiment 3. FIG. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on the modification of Embodiment 3. FIG. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on Embodiment 4. FIG. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on Embodiment 5. FIG. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on the modification of Embodiment 5. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on Embodiment 6. 11A and 11B are a cross-sectional view perpendicular to the optical traveling direction of the semiconductor laser apparatus according to the seventh embodiment and a plan view showing a processing region in a surface facing the heat sink of the submount, respectively. 12A and 12B are plan views showing a processing region in a plane facing the heat sink of the submount constituting the semiconductor laser apparatus according to the two modifications of the seventh embodiment, respectively. It is sectional drawing which is perpendicular to the optical traveling direction of the semiconductor laser apparatus which concerns on Embodiment 8. FIG.

Embodiment 1.
1 and 2 are for explaining the configuration of the semiconductor laser device according to the first embodiment, and FIG. 1 shows a cross-sectional view (FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device and a semiconductor laser. A cross-sectional view (FIG. 1B) perpendicular to the optical traveling direction of the chip and a plan view (FIG. 1B) showing a surface-treated region provided on the surface facing the submount of the semiconductor laser chip so that the bonding material does not adhere. FIG. 1C). Further, FIG. 2 shows a cross-sectional view (FIG. 2A) perpendicular to the optical traveling direction of the semiconductor laser chip corresponding to FIG. 1B and a surface facing the submount of the semiconductor laser chip corresponding to FIG. 1C as an explanation of a modification. FIG. 2B is a plan view (FIG. 2B) showing a treated area that has been surface-treated so that the provided bonding material does not adhere. In addition, in the figure including the following embodiments, the traveling direction of the light in the semiconductor laser is the y direction, the arrangement direction in which a plurality of active layers extending in the light traveling direction are arranged is the x direction, and the stacking direction of the semiconductor layers is z. Explained as a direction.

As shown in FIG. 1A, the semiconductor laser device 1 has a submount 3 on the upper surface electrode 52t side on which a plurality of active layers 4a to 4c (collectively referred to as active layer group 4) of the semiconductor laser chip 5 are formed. , The heat sink 2 is sequentially laminated and configured.

The semiconductor laser chip 5 is configured such that a laminated body 51 in which semiconductor layers extending along the optical traveling direction (y direction) are laminated (details are omitted) is sandwiched between the lower surface electrode 52b and the upper surface electrode 52t. Is. On the lowermost surface (lower surface electrode 52b side) of the laminated body 51, for example, a GaAs substrate having the (001) plane as the main surface is arranged, and the clad layer, the active layer group 4 and the like forming a quantum well are formed from the GaAs substrate. However, it is formed so as to form a predetermined form by crystal growth, etching, or the like. Therefore, in the present application, the upper electrode in the figure is referred to as the lower surface electrode 52b, and the lower electrode is referred to as the upper surface electrode 52t, with reference to the direction of crystal growth. The upper surface electrode 52t and the lower surface electrode 52b are made of, for example, a metal such as Au, Ge, Zn, Pt, or Ti, which are conductors, in order to allow an electric current to flow from the outside. Further, plating layers 53t and 53b are formed on the outside thereof for bonding with other members or for surface protection. Both end faces of the laminated body 51 in the light traveling direction are formed by cleavage, for example.

The crystal growth is, for example, an organic metal vapor deposition method (MOCVD: Metal Organic Chemical Vapor Deposition), but the crystal growth is not limited to this, and it goes without saying that the crystal growth may be formed by various methods. On the other hand, the three active layers 4a to 4c constituting the active layer group 4 each have a striped shape extending in the light traveling direction (y direction) with the same specifications, and are in the light traveling direction (y direction) and the stacking direction of the laminated body 51. They are arranged at equal intervals in the direction (x direction) perpendicular to (z direction). A striped resonator is formed between both end faces of each active layer 4a to 4c due to cleavage, and the light emitted by injecting a current through the upper surface electrode 52t and the lower surface electrode 52b is amplified in the resonator. And leads to laser oscillation. Therefore, the regions of the active layers 4a to 4c are light emitting regions, which are also referred to as striped light emitting regions. The cavity length is often 150 μm to 300 μm, but is not limited to this range.

The submount 3 is a heat transfer member in which metallized layers 32e and 32c are formed on both surfaces of a base material 31 such as an AlN (aluminum nitride) sintered body. Further, the heat sink 2 is a heat dissipation component made of Cu (copper), Al (aluminum), or the like. The semiconductor laser chip 5 has the upper surface electrode 52t on which the active layer group 4 is arranged facing the metallized layer 32e of the submount 3 and is fixed by a bonding material 6 such as solder. In the submount 3, the metallized layer 32c formed on the opposite side of the metallized layer 32e formed on the facing surface 3fe (FIG. 3) side to the semiconductor laser chip 5 faces the heat sink 2, and the bonding material 7 such as solder is used. , Is fixed.

Here, in the first embodiment, as shown in FIGS. 1B and 1C, surface treatment is performed so that the bonding material 6 does not adhere to a part of the surface 5ft facing the submount 3 of the semiconductor laser chip 5. The treated treatment area R5t is formed. The processing region R5t was set corresponding to the regions P4a to P4c in which each of the active layers 4a to 4c was projected onto the facing surface 5ft. The projected region is also a region directly above each of the active layers 4a to 4c, and the regions P4a to P4c to which the processing region R5t is set are straight lines connecting each of the active layers 4a to 4c and the heat sink 2 at the shortest distance. This is the area through which.

Among such regions P4a to P4b, the treatment regions R5t are dispersedly arranged at three locations in the traveling direction for the region P4a corresponding to the active layer 4a, and the region P4b corresponding to the active layer 4b is dispersed. , The processing areas R5t were distributed and arranged at two places in the traveling direction. Then, the processing region R5t was not arranged for the region P4c corresponding to the active layer 4c. That is, the arrangement of the processing region R5t was adjusted so that the area (or the range in the traveling direction of the light) in which the processing region R5t was set had a relationship of P4a> P4b> P4c.

Assuming that, for example, AuSn (gold tin) solder is used as the bonding material 6, the portion of the plating layer 53t other than the processing region R5t is formed by Au plating, and the treatment region R5t portion is formed by Ni (nickel) plating. I did it. As described above, when the semiconductor laser chip 5 having the processing region R5t is bonded to the submount 3 by using the bonding material 6, the bonding material 6 is formed between the submount 3 and the facing surface 5ft in the portion other than the processing region R5t. Intervenes to form a strong heat transfer path. On the other hand, since AuSn solder does not get wet with Ni, a bonding relationship is not formed between the facing surface 5ft and the bonding material 6 (after curing) in the processing region R5t portion, and the solder is merely in contact with each other. .. In some cases, there may be a gap between the treated area R5t and the bonding material 6.

The operation of the semiconductor laser device 1 configured in this way will be described. When a current is injected into the semiconductor laser chip 5 via the upper surface electrode 52t and the lower surface electrode 52b, laser light is emitted from the end faces of the active layers 4a to 4c. At this time, heat is generated in each of the active layers 4a to 4c and the temperature rises. However, due to the temperature rise, the temperature difference generated between the active layers 4a and 4c becomes a driving force and is dissipated to the heat sink 2, and the heat is dissipated. Deprived (cooled). The temperature rise continues until the amount of heat generated in each of the active layers 4a to 4c and the amount of heat taken away by heat dissipation are balanced, and when the amount is balanced, the temperature becomes constant.

At this time, in the heat dissipation from each of the active layers 4a to 4c toward the heat sink 2, the path passing through the regions P4a to P4c becomes the shortest path to the heat sink 2. However, as described above, depending on the arrangement of the treated region R5t, the active layers 4a, 4b, and 4c have different bonding areas with the bonding material 6 in the regions P4a, P4b, and P4c located in the shortest path, respectively. In the portion where the processing region R5t is arranged, since there is no bonding between the facing surface 5ft and the bonding material 6, the thermal resistance is higher than when there is bonding. That is, the processing region R5t functions as a division region that divides the heat transfer path from each of the active layers 4a to 4c to the heat sink 2.

Of course, there is also a heat transfer path that bypasses the portion where the joint is formed between the facing surface 5ft and the bonding material 6 outside the processing region R5t, but in that case, the path length becomes long, so that heat is also generated. The resistance increases. As the thermal resistance increases, the temperature difference required to balance the amount of heat generated and the amount of heat taken away by heat dissipation increases. That is, the larger the area where the processing region R5t is arranged, the higher the thermal resistance (lower the heat dissipation) and the higher the temperature. Conversely, the smaller the area where the processing region R5t is arranged and the lower the thermal resistance (higher heat dissipation), the lower the temperature can be kept.

The area in which the bonding between the facing surface 5ft and the bonding material 6 is hindered by the treatment region R5t is the active layer 4a, the active layer 4b, and the active layer 4c in descending order, and the active layer 4c and the active layer are in descending order of heat dissipation. It becomes a layer 4b and an active layer 4a. Therefore, the temperature during operation is the active layer 4c <active layer 4b <active layer 4a, and the temperature of the active layer 4a is the highest. A semiconductor laser has a feature that the oscillation wavelength becomes longer as the temperature rises. Therefore, when compared for each active layer 4a to 4c, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c. In this way, different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced.

The processing region R5t does not have to be limited to the arrangement within the regions P4a to P4c as shown in FIG. 1C. For example, as in the modified examples shown in FIGS. 2A and 2B, the regions may extend beyond the regions P4a to P4c. Further, the processing region R5t may not be dispersed in each of the regions P4a to P4c, but may be arranged together. Alternatively, they may be arranged in a dotted pattern or a mottled pattern. Even in that case, the area where the processing region R5t is arranged may be different in each of the regions P4a to P4c.

Further, in the above example, AuSn solder is used as the bonding material 6, the portion of the plating layer 53t other than the processing region R5t is formed by Au plating, and the treatment region R5t portion is formed by Ni plating. There is no such thing. For example, a metal film such as Al (aluminum) to which solder does not adhere or an insulating film such as Si (silicon) may be provided in the processing region R5t, and the other region may be Cu (copper) instead of Au. May be good.

Furthermore, when a so-called resin-based adhesive such as an epoxy resin is used as the bonding material 6, the surface roughness other than the treated area R5t is made coarser than that of the treated area R5t so that the bonding material 6 does not adhere. You may do so. In the following embodiments, the expressions "non-adhesive", "non-adhesive", and "non-wet" are used, which are easy to imagine, but practically, "low adhesiveness" and "adhesiveness" are used. Thermal resistance increases even when "low" or "low wettability". Therefore, in the following embodiments, the description of "non-adhesive", "non-adhesive" or "not wet" means "low adhesiveness", "low adhesiveness" or "low wettability". May be read as. That is, in the treated region R5t, if the material has lower adhesiveness, bondability, or wettability with the bonding material 6 than the other portions, or if it is in a surface state, the type, material, or surface of the bonding material 6 The combination of states is arbitrary.

Embodiment 2.
In the first embodiment, an example in which a region where the bonding material does not adhere is provided on the surface facing the submount of the semiconductor laser chip in order to make the operating temperature different for each active layer has been described. In the second embodiment, an example in which a region where the bonding material does not adhere is provided on the surface of the submount facing the semiconductor laser chip will be described. 3A to 3C are for explaining the configuration of the semiconductor laser device according to the second embodiment, and FIGS. 3A is a cross-sectional view (corresponding to FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device, FIG. 3B. Is a plan view showing a treated area that has been surface-treated so that the bonding material does not adhere, which is set on the surface facing the semiconductor laser chip of the submount, and FIG. 3C is a cross-sectional view perpendicular to the optical traveling direction of the submount. be. Further, FIG. 4 is a plan view showing a treated area which has been surface-treated so that the bonding material does not adhere to the surface facing the semiconductor laser chip of the submount corresponding to FIG. 3B as an explanation of a modification. 4A) and 3C are cross-sectional views perpendicular to the optical traveling direction of the submount corresponding to FIG. 3C (FIG. 4B).

In the semiconductor laser apparatus according to the second embodiment and the subsequent embodiments, the semiconductor laser chip itself excluding the surface treatment and the heat sink have the same configuration. Further, with respect to other members (sub-mounts, joining materials), the same parts will not be described.

In the semiconductor laser apparatus 1 according to the second embodiment, as shown in FIG. 3A, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. Here, as shown in FIGS. 3B and 3C, a surface treatment was applied to a part of the metallized layer 32e constituting the facing surface 3fe of the submount 3 to the semiconductor laser chip 5 so that the bonding material 6 does not adhere to the metallized layer 32e. The processing region R3e is formed. The processing region R3e was set corresponding to the regions P4a to P4c of the facing surfaces 3fe on which the active layers 4a to 4c when the semiconductor laser chip 5 was bonded were projected. The regions P4a to P4c on the facing surface 3fe are also regions through which a straight line connecting each of the active layers 4a to 4c and the heat sink 2 passes at the shortest.

Of such regions P4a to P4b, the treatment regions R3e are dispersedly arranged at three locations in the traveling direction for the region P4a corresponding to the active layer 4a, and the region P4b corresponding to the active layer 4b is dispersed. , The processing areas R3e were distributed and arranged at two places in the traveling direction. Then, the processing region R3e was not arranged for the region P4c corresponding to the active layer 4c. That is, the arrangement of the processing area R3e was adjusted so that the area in which the processing area R3e was set had a relationship of P4a> P4b> P4c.

Assuming that AuSn (gold tin) solder as exemplified in the first embodiment is used as the joining material 6, Au covers the surface of the metallized layer 32e other than the processing region R3e, and the treatment region. The surface of the R3e portion was covered with Ni. In this way, when the semiconductor laser chip 5 is bonded to the submount 3 having the processing region R3e using the bonding material 6, the bonding material is formed between the semiconductor laser chip 5 and the facing surface 3fe in the portion other than the processing region R3e. 6 intervenes to form a strong heat transfer path. On the other hand, since AuSn solder does not get wet with Ni, a bonding relationship is not formed between the facing surface 3fe and the bonding material 6 (after curing) in the processing region R3e portion, and the solder is merely in contact with each other. .. In some cases, there may be a gap between the treated area R3e and the bonding material 6.

When the semiconductor laser device 1 configured in this way is operated, as described in the first embodiment, the active layers 4a to 4c generate heat, but in the heat dissipation toward the heat sink 2, the region on the facing surface 3fc is generated. The path passing through P4a to P4c is also the shortest path to the heat sink 2. And here, too, the processing region R3e functions as a division region that divides the heat transfer path from each of the active layers 4a to 4c to the heat sink 2.

Further, the areas where the bonding between the facing surface 3fe and the bonding material 6 is hindered by the treated region R3e are the active layer 4a, the active layer 4b, and the active layer 4c in descending order, and the active layer 4c in descending order of heat dissipation. , The active layer 4b and the active layer 4a. Therefore, as in the first embodiment, the operating temperature is the active layer 4c <active layer 4b <active layer 4a, and the temperature of the active layer 4a is the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c. In this way, different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced.

The processing region R3e does not have to be limited to the arrangement within the regions P4a to P4c as shown in FIG. 3B. For example, as in the modified examples shown in FIGS. 4A and 4B, the region may extend beyond the regions P4a to P4c. Further, the processing region R3e may not be dispersed in each of the regions P4a to P4c, but may be arranged together. Alternatively, they may be arranged in a dotted pattern or a mottled pattern. Even in that case, the area where the processing region R3e is arranged may be different in each of the regions P4a to P4c.

Further, when used in combination with the processing region R5t on the facing surface 5ft described in the first embodiment, the joining material 6 is sandwiched between the materials to which the joining material 6 does not adhere in that portion. In such a case, depending on the joining conditions, the joining material 6 is removed from the portion sandwiched between the processing region R5t and the processing region R3e (the portion similarly surface-treated at the opposite portion) to form a space, and the thermal resistance is further increased. Therefore, it may be possible to further increase the temperature difference.

Further, in the above example, AuSn solder is used as the bonding material 6, the surface of the portion of the metallized layer 32e other than the processing region R3e is Au, and the treatment region R3e portion is formed of Ni. There is no such thing. For example, an insulating film such as Al or Si may be provided in the processing region R3e, and the other region may be Cu instead of Au. Further, the surface roughness may be changed between the processing region R3e and the other portion. That is, also in the second embodiment, if the treated area R3e is in a material or surface state in which the joining material 6 does not adhere or is not joined to the joining material 6 as compared with the other parts, the joining material 6 is formed. The combination of the type, material or surface condition of is arbitrary.

Embodiment 3.
In the first or second embodiment, an example in which a region to which the bonding material does not adhere is provided between the semiconductor laser chip and the submount in order to make the operating temperature different for each active layer has been described. In the third embodiment, an example using a submount having substrates having different thermal conductivitys in the arrangement direction will be described. 5 and 6 are for explaining the configuration of the semiconductor laser device according to the third embodiment, and FIG. 5 is a cross-sectional view (corresponding to FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device, and FIG. Is a cross-sectional view (same as above) perpendicular to the optical traveling direction of the semiconductor laser device according to the modified example.

In the semiconductor laser apparatus 1 according to the third embodiment, as shown in FIG. 5, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. Then, as a characteristic configuration in the third embodiment, the submount 3 is a base material 31 in which the partial base materials 31a to 31c having different properties are arranged so as to be arranged along the arrangement direction of the active layers 4a to 4c. Was used. Each of the partial base materials 31a to 31c forms a rectangular parallelepiped in which the cross-sectional shape shown in the figure continues along the light traveling direction (y direction), and is sandwiched between the metallized layer 32e and the metallized layer 32c as in other embodiments. ing.

The straight line connecting the active layer 4a and the heat sink 2 passes through the partial base material 31a, the straight line connecting the active layer 4b and the heat sink 2 passes through the partial base material 31b, and the straight line connecting the active layer 4c and the heat sink 2 is the partial base material. It is arranged so as to pass through 31c. The partial base materials 31a to 31c are each composed of AlN sintered bodies having different porosities. Among the base materials 31, the partial base material 31a has the highest porosity and the partial base material 31c has the lowest porosity. It was set to be. As a result, among the base materials 31, the partial base material 31a has the lowest thermal conductivity, and the partial base material 31c has the highest thermal conductivity.

Therefore, the order of highest heat dissipation is the active layer 4c, the active layer 4b, and the active layer 4a, and the operating temperature is the active layer 4c <active layer 4b <active layer 4a, as in the first or second embodiment. , The temperature of the active layer 4a becomes the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c, and different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced. Become.

The combination of the partial base materials having different thermal conductivity is not limited to the form in which the partial base materials 31a to 31c having different properties are arranged for each of the active layers 4a to 4c as shown in FIG. For example, as in the modified example shown in FIG. 6, the partial base materials 31d and 31e have a trapezoidal cross-sectional shape and different thermal conductivity from each other (the partial base material 31e has a higher thermal conductivity). May be combined so as to match in the thickness direction.

In this case, in each of the active layers 4a to 4c, the ratio of the heat transfer length of the partial base material 31d and the heat transfer length of 31e in the submount 3 is different in the heat transfer path to the heat sink 2. The active layer 4a has the lowest ratio of the partial base material 31e having a high thermal conductivity, and the active layer 4c has the highest ratio of the partial base material 31e having a high thermal conductivity. Therefore, as in the example of FIG. 5, the order of high heat dissipation is the active layer 4c, the active layer 4b, and the active layer 4a, and the operating temperature is the active layer 4c <active layer 4b <active layer 4a.

In the above example, the partial base materials 31a to 31e are all made of the same material (AlN), and the thermal conductivity is different due to the different porosity, but the present invention is not limited to this. For example, members having different thermal conductivitys inherent in the materials such as Si ₃ N ₄ (silicon nitride) and Al ₂ O ₃ (alumina) may be combined. Further, the number and shape of the partial base materials are arbitrary as long as the combination has different thermal resistance from each of the active layers 4a to 4c to the heat sink 2.

Embodiment 4.
In the third embodiment, an example in which the temperature of each active layer is made different by arranging the partial base materials having different thermal conductivity in the submount has been described. In the fourth embodiment, an example in which a cavity extending in the arrangement direction is provided in the middle portion in the thickness direction of the submount will be described. FIG. 7 is for explaining the configuration of the semiconductor laser device according to the fourth embodiment, and is a cross-sectional view perpendicular to the optical traveling direction of the semiconductor laser device.

In the semiconductor laser apparatus 1 according to the fourth embodiment, as shown in FIG. 7, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. Then, as a characteristic configuration in the fourth embodiment, the submount 3 extends in the arrangement direction (x direction) in the middle portion in the thickness direction (z direction), and the thickness (depending on the position with respect to the active layers 4a to 4c) ( The cavities 3sc with different ta and tb) were formed.

The thickness ta of the cavity 3sc on the straight line connecting the active layer 4a and the heat sink 2 is thicker than the thickness tb of the cavity 3sc on the straight line connecting the active layer 4b and the heat sink 2, and is on the straight line connecting the active layer 4c and the heat sink 2. Has no cavity 3sc. Since the cavity portion has high thermal resistance, the order of high heat dissipation is the active layer 4c, the active layer 4b, and the active layer 4a. <It becomes the active layer 4a, and the temperature of the active layer 4a becomes the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c, and different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced. Become.

The cavities 3sc may continue for a length in the traveling direction (y direction) of the light of the active layer group 4, but a plurality of cavities 3sc may be arranged along the traveling direction of the light. Alternatively, each active layer 4a to 4c may form a cavity 3sc having a different thickness (z direction) or width (x direction) (morphology) depending on the position in the traveling direction of light. That is, the cavities 3sc perpendicular to the thickness direction may be formed with different thicknesses or widths (morphologies) of the voids for each of the active layers 4a to 4c or depending on the position in the arrangement direction.

Embodiment 5.
In the fourth embodiment, an example in which the temperature of each active layer is made different by forming a cavity in the submount in the direction perpendicular to the thickness direction has been described. In the fifth embodiment, an example in which the submount is provided with a cavity extending in the thickness direction according to the arrangement of the active layer will be described. 8 and 9 are for explaining the configuration of the semiconductor laser device according to the fifth embodiment, and FIG. 8 is a cross-sectional view (corresponding to FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device, and FIG. Is a cross-sectional view (same as above) perpendicular to the optical traveling direction of the semiconductor laser device according to the modified example.

In the semiconductor laser apparatus 1 according to the fifth embodiment, as shown in FIG. 8, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. Then, as a characteristic configuration in the fifth embodiment, a plurality of cavities 3st extending in the thickness direction (z direction) are formed according to the arrangement of the active layers 4a to 4c of the submount 3.

Specifically, deep cavities 3st are formed on both sides of the shortest path from the active layer 4a, and shallow cavities 3st are formed between the active layer 4b and the active layer 4c. As a result, there is no difference in the shortest path from each of the active layers 4a to 4c to the heat sink 2. However, with respect to the side in the arrangement direction (x direction) of each shortest path, the length (thickness direction: z direction) of the cavities 3st on both sides of the shortest path from the active layer 4a is the longest, and from the active layer 4c. The length of the cavity 3st on both sides of the shortest path is the shortest.

In the above-mentioned first to fourth embodiments, it has been described that the temperature difference is caused by the difference in thermal resistance in the shortest path. However, when the area of the heat absorbing source (heat sink 2) is larger than that of the heat generating source (each active layer 4a to 4c), not only the shortest path to the heat absorbing source but also the heat flow in the direction perpendicular to the shortest path. It is also important. When the heat generation sources are arranged in the arrangement direction and the dimensions of the heat generation source and the heat absorption source in the arrangement direction are different, such as in a laser array, the heat flow in the arrangement direction is important.

The order of ease of heat flow in the arrangement direction is the active layer 4c, the active layer 4b, and the active layer 4a due to the arrangement of the cavity 3st. When the active layer 4b <active layer 4a, the temperature of the active layer 4a becomes the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c, and different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced. Become.

The number or depth of the cavities 3st extending in the thickness direction, and the combination of the widths in the arrangement direction are arbitrary. For example, as shown in FIG. 9, the cavities 3st having different depths and widths are provided. Is also good. Further, the active layer group 4 may be continued over the length in the traveling direction of the light, but a plurality of active layer groups 4 may be arranged along the traveling direction of the light. That is, it suffices to form the cavity 3st having a different thickness or width (morphology) of the void depending on the position in the arrangement direction.

Embodiment 6.
In the above embodiments 4 and 5, an example in which the temperature of each active layer is different depending on the internal structure of the submount has been described. In the sixth embodiment, an example in which the thickness of the submount is changed depending on the arrangement direction will be described. FIG. 10 is for explaining the configuration of the semiconductor laser device according to the sixth embodiment, and is a cross-sectional view (corresponding to FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device.

In the semiconductor laser apparatus 1 according to the sixth embodiment, as shown in FIG. 10, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. Then, as a characteristic configuration in the sixth embodiment, the submount 3 whose thickness changes along the arrangement direction is used. The thickness decreases monotonically from the side corresponding to the active layer 4a toward the side corresponding to the active layer 4c, and the cross-sectional shape perpendicular to the light traveling direction is the metallized layer 32c with respect to the surface on the metallized layer 32e side. The side faces form a triangle with a constant slope.

As a result, the distance between each of the active layers 4a to 4c and the heat sink 2 is the longest in the active layer 4a and the shortest in the active layer 4c. Therefore, the order of highest heat dissipation is the active layer 4c, the active layer 4b, and the active layer 4a, and the operating temperature is the active layer 4c <active layer 4b <active layer 4a, as in each of the above embodiments. The temperature of the active layer 4a becomes the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c, and different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced. Become.

As for the submount shape in which the other surface is inclined with respect to one surface, a desired shape can be easily obtained by using a method such as polishing. In this example, the cross-sectional shape of the submount 3 is triangular, but as long as it changes monotonically, one end may be trapezoidal with a certain thickness.

The shape in which the other surface is inclined with respect to one surface is not always a preferable form for manufacturing the semiconductor laser device 1. When the submount 3 in which one surface and the other surface are parallel in the other embodiment described above is used, for example, the bonding between the heat sink 2 and the submount 3 and the bonding between the submount 3 and the semiconductor laser chip 5 are used. Can be executed at the same time without any special preparation. However, in the case of simply performing simultaneous bonding using the submount 3 in which one surface and the other surface are inclined as in the semiconductor laser device 1 according to the sixth embodiment, for example, the semiconductor laser chip 5 Will be placed on the tilted metallized layer 32e. Then, the semiconductor laser chip 5 may slide down on the metallized layer 32e until the bonding materials 6 and 7 are solidified, resulting in misalignment.

Therefore, in the present embodiment, the solder material used for the joining material 7 is selected to have a higher melting point than the solder material used for the joining material 6, and the submount 3 is once joined to the heat sink 2 using the joining material 7. After that, the heat sink 2 is tilted so that the metallized layer 32e is horizontal, and the semiconductor laser chip 5 is bonded using the bonding material 6 at a temperature lower than the melting point of the bonding material 7 and higher than the melting point of the bonding material 6. Since the manufacturing process takes a lot of time and effort in this way, it is generally avoided to use a form in which the member is tilted, but since the submount 3 can be formed by a simple method such as polishing, it is inexpensive and easy. It is possible to obtain a semiconductor laser device 1 having a high coherence reducing effect.

Embodiment 7.
In the semiconductor laser apparatus according to the seventh embodiment, the temperature of each active layer is changed by controlling the adhesion region of the bonding material on the bonding surface between the submount and the heat sink. 11A and 11B are for explaining the configuration of the semiconductor laser device according to the seventh embodiment, and FIG. 11A is a cross-sectional view (corresponding to FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device, FIG. 11B. Is a plan view showing a treated area which has been surface-treated so that the bonding material does not adhere to the surface facing the heat sink of the submount. Further, FIG. 12 shows, as an explanation of the two types of deformation examples, a treatment set on the surface of the submount corresponding to FIG. 11B of the first deformation example facing the heat sink, which is subjected to surface treatment so that the bonding material does not adhere. A plan view (FIG. 12A) showing the region and a treated region set on the surface facing the heat sink of the submount corresponding to FIG. 11B of the second modification, which has been surface-treated so that the bonding material does not adhere, are shown. It is a plan view (FIG. 12B).

In the semiconductor laser apparatus 1 according to the seventh embodiment, as shown in FIG. 11A, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. Here, as shown in FIG. 11B, a treated region R3c that has been surface-treated so that the joining material 7 does not adhere is formed on a part of the metallized layer 32c constituting the facing surface 3fc of the submount 3 with respect to the heat sink 2. Has been done. The processing region R3c corresponds to the regions P4a to P4c on which the active layers 4a to 4c when the semiconductor laser chip 5 is bonded are projected from the facing surface 3fc, and is set so as to be biased to one side in the arrangement direction. Specifically, from a line parallel to the traveling direction of light located outside the active layer 4c and inside the region P5 on which the semiconductor laser chip 5 is projected, to the entire region on the side where the active layer group 4 exists. The processing area R3c was set.

Assuming that the AuSn solder exemplified as the bonding material 6 of the first embodiment is used as the bonding material 7, Au covers the surface of the metallized layer 32c other than the processing area R3c, and the processing area R3c portion. Made Ni cover the surface. In this way, when the heat sink 2 is joined to the submount 3 having the processing region R3c by using the bonding material 7, the bonding material 7 is interposed between the heat sink 2 and the facing surface 3fc in the portion other than the processing region R3c. Therefore, a strong heat transfer path is formed. On the other hand, since AuSn solder does not get wet with Ni, a bonding relationship is not formed between the facing surface 3fc and the bonding material 7 (after curing) in the processing region R3c portion, and the solder is merely in contact with each other. .. In some cases, a gap may be generated between the treated area R3c portion and the bonding material 7.

In this example, in the shortest path between each of the active layers 4a to 4c and the heat sink 2, there is no region where the bonding material 7 and the facing surface 3fc are bonded, as compared with the portion where the bonding is formed. High thermal resistance. Therefore, the heat transfer in the detour route via the region where the bonding material 7 and the facing surface 3fc are joined becomes predominant over the heat transfer in the shortest path, and the heat dissipation in the detour route is the active layers 4a to 4c. It greatly affects the heat dissipation of each.

Since the portion where the junction is formed (other than the region R3c) is located outside the region P4c on which the active layer 4c is projected, the length of the detour route of the active layer 4a is the longest, and the detour route of the active layer 4c The length is the shortest. Therefore, the order of highest heat dissipation is the active layer 4c, the active layer 4b, and the active layer 4a, and the operating temperature is the active layer 4c <active layer 4b <active layer 4a, as in each of the above embodiments. Therefore, the temperature of the active layer 4a becomes the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c, and different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced. Become.

The processing region R3c does not need to be arranged so that all the regions P4a to P4c are contained as shown in FIG. 11B. For example, the region P4c is partially or not contained at all and is partially active. The layer may be mainly composed of the shortest path. Alternatively, for example, as in the modified example shown in FIG. 12A, there may be a portion where the processing region R3c is not formed along the light traveling direction. Further, as in the second modification shown in FIG. 12B, the area where the processing region R3c is not formed may be changed according to the regions P4a to P4c. That is, the arrangement (area) of the processing region R3c may be biased to one side in the arrangement direction.

Alternatively, the object of arrangement of the processing region to which the joining material 7 does not adhere may be the facing surface 2fs of the heat sink 2 to the submount 3. Further, a processing region to which the joining material 7 does not adhere may be arranged on both the facing surface 2fs of the heat sink 2 and the facing surface 3fc of the submount 3. In this case, depending on the joining conditions, the joining material 7 escapes from the portion sandwiched between the processing region on the facing surface 2fs and the processing region R3c on the facing surface 3fc to form a space, the thermal resistance becomes higher, and the temperature difference is further increased. It may be possible to attach it.

Further, in the above example, AuSn solder is used as the bonding material 7, the surface of the portion of the metallized layer 32c (including the processing region on the facing surface 2fs) other than the processing region R3c is Au, and the treatment region R3c portion is Ni. An example of formation is shown, but it is not limited to this. For example, an insulating film such as Al or Si may be provided in the processing region R3c, and the other region may be Cu instead of Au. Further, the surface roughness may be changed between the processing region R3c and the other portion. That is, even in the seventh embodiment, if the treated region R3c is in a material or surface state in which the joining material 7 does not adhere or is not joined to the joining material 7 as compared with other parts, the joining material 7 is formed. The combination of the type, material or surface condition of is arbitrary.

Embodiment 8.
In each of the above embodiments, an example is shown in which a temperature difference is applied to each active layer depending on the form of a semiconductor laser chip, a submount, or a heat sink, or the arrangement of a region to be surface-treated. In the eighth embodiment, an example in which a temperature difference is provided for each active layer in the positional relationship between the semiconductor laser chip, the submount, and the heat sink in the arrangement direction will be described. FIG. 13 is for explaining the configuration of the semiconductor laser device according to the eighth embodiment, and is a cross-sectional view (corresponding to FIG. 1A) perpendicular to the optical traveling direction of the semiconductor laser device.

In the semiconductor laser apparatus 1 according to the eighth embodiment, as shown in FIG. 13, the semiconductor laser chip 5 is fixed to the submount 3 by a bonding material 6 such as solder, and the submount 3 is bonded to solder or the like. It is fixed to the heat sink 2 by the material 7. However, as a characteristic configuration in the eighth embodiment, the semiconductor laser chip 5 is joined to the submount 3 with a part protruding from the submount 3 in the arrangement direction (x direction), and further, the submount 3 is also joined. , Partially protrudes from the heat sink 2 in the same direction and is joined.

As a result of the joining that causes protrusion in the arrangement direction, the submount 3 that contributes to heat dissipation does not exist directly above the active layer 4a (the region projected downward in the figure: corresponding to P4a). Further, the submount 3 exists immediately above the active layer 4b (corresponding to P4b), but the heat sink 2 does not exist. On the other hand, the submount 3 and the heat sink 2 are present directly above the active layer 4c (corresponding to P4c).

That is, the heat dissipation path of the active layer 4a constitutes a heat transfer in the arrangement direction in the semiconductor laser chip 5, radiation from the facing surface 5ft, or a sealed body (not shown) in which the semiconductor laser device 1 is sealed. The heat is transferred to the resin, and there is no heat transfer path directly connected to the heat sink 2. Further, although the submount 3 is bonded directly above the active layer 4b, the heat sink 2 does not exist in the portion corresponding to the region P4b, and the heat radiation to the heat sink 2 is in the arrangement direction in the submount 3. Heat transfer is required.

Therefore, the order of highest heat dissipation is the active layer 4c, the active layer 4b, and the active layer 4a, and the operating temperature is the active layer 4c <active layer 4b <active layer 4a, as in each of the above embodiments. Therefore, the temperature of the active layer 4a becomes the highest. Therefore, the order of the longest wavelength is the active layer 4a, the active layer 4b, and the active layer 4c, and different oscillation wavelengths can be obtained from each of the active layers 4a to 4c, and coherence can be effectively reduced. Become.

In the above example, the protrusion amount W5 of the semiconductor laser chip ₅ with respect to the submount 3 is set so that the semiconductor laser chip 5 completely protrudes from the submount 3 in the region directly above the active layer 4a. Further, the protrusion amount W3 of the submount ₃ with respect to the heat sink 2 was set so that the submount 3 completely protrudes from the heat sink 2 in the region directly above the active layer 4b. However, the present invention is not limited to this, and a part of the region directly under the active layer may protrude in the arrangement direction, and a biased heat transfer path may be formed from the active layer on one end side to the active layer on the other end side. If it is formed, the amount of protrusion W ₅ and W ₃ can be set arbitrarily.

In each of the above-described embodiments, the case where the number of active layers constituting the active layer group 4 is 3 has been described, but the present invention is not limited to this. In each of the above embodiments, by biasing at least one of the member configuration, the surface treatment, and the member positional relationship to one side in the arrangement direction, each active layer is directed from one end side to the other end side in the arrangement direction. The heat dissipation is changed in one direction (decreased or improved). As a result, if there are at least two or more active layers, different wavelengths can be oscillated to reduce coherence. Further, since laser light having different wavelengths can be oscillated by the number of active layers, there is no useless active layer for reducing coherence, and the semiconductor laser apparatus 1 having a high coherence reducing effect can be easily obtained inexpensively.

On the other hand, in the example of adjusting the region where the surface treatment for reducing the adhesiveness of the joining material is performed as in the first, second, or seventh embodiments, the region can be freely adjusted by a technique such as masking, and the member configuration. It is possible to easily change the variation, unlike the case of changing the form. Therefore, when the heat dissipation property is changed by the distribution of the surface treatment region, it is not always necessary to bias the heat dissipation property of each active layer to one side in the arrangement direction. For example, if a certain active layer is formed to have the same temperature, the wavelengths of some of the active layers will be the same, and the coherence reduction effect will be diminished, but it can be easily realized. A semiconductor laser device 1 having a high coherence reducing effect can be easily obtained at low cost.

Further, although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are specific embodiments. It is not limited to the application of, but can be applied to the embodiment alone or in various combinations. Therefore, innumerable variations not exemplified are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

As described above, according to the semiconductor laser apparatus 1 according to each of the first, second, and seventh embodiments, or a combination thereof, a plurality of (with the same specifications) extending along the traveling direction (y direction) of the light. A plate-shaped semiconductor laser chip 5 in which light emitting regions (active layers 4a to 4c) are arranged at intervals in a direction perpendicular to the traveling direction (arrangement direction: x direction) and a sub bonded to the semiconductor laser chip 5. The mount 3 is provided with a heat sink 2 bonded to a surface (opposing surface 3fc) opposite to the surface (facing surface 3fe) to which the semiconductor laser chip 5 of the submount 3 is bonded, and the semiconductor laser chip 5 and the submount are provided. A plurality of light emitting regions are provided on at least one of each of the facing surfaces of 3 (facing surface 5ft, facing surface 3fe) and each of the facing surfaces of the submount 3 and the heat sink 2 (facing surface 3fc, facing surface 2fs). The setting range in the traveling direction (y direction) is changed according to the position (particularly, each region P4a to P4c) in the arrangement direction (x direction) of (active layers 4a to 4c), and the bonding material used for bonding (bonding material 6). Or, since the treatment area (for example, the treatment area R5t, the treatment area R3e, the treatment area R3c, etc.) having reduced the adhesiveness of the bonding material 7) is provided, the setting target of surface treatment can be easily set. By the adjustable method, the thermal resistance at the joint portion changes along the arrangement direction, and the wavelength can be shifted by giving a temperature difference to the active layers 4a to 4c having the same specifications, so that it is inexpensive and easy. , A semiconductor laser device 1 having a high coherence reducing effect can be obtained.

In particular, any one of the facing surfaces of the semiconductor laser chip 5 and the submount 3 (facing surface 3fc and facing surface 2fs) and the facing surfaces of the submount 3 and the heat sink 2 (facing surface 3fc and facing surface 2fs) is If the processing regions are provided in the same portions facing each other, the difference in thermal resistance can be more reliably generated.

Further, the bonding material 6 or the bonding material 7 is gold-tin solder, and if a layer of nickel, aluminum, or an insulating film is formed on the surface of the treated area, no special material is required and gold-tin solder is used. Does not adhere to the treated area and can surely cause a difference in thermal resistance.

Alternatively, according to the semiconductor laser apparatus 1 according to each of the above embodiments (particularly, each of embodiments 3 to 6, 8 or a combination thereof), a plurality of extending along the traveling direction (y direction) of light. The plate-shaped semiconductor laser chip 5 and the semiconductor laser chip in which the light emitting regions (active layers 4a to 4c) of the above are arranged at intervals in the direction perpendicular to the traveling direction (arrangement direction: x direction). A plurality of submounts 3 bonded to the submount 3 and a heat sink 2 bonded to the opposite surface (facing surface 3fc) of the surface (facing surface 3fe) to which the semiconductor laser chip 5 of the submount 3 is bonded are provided. The thermal resistance of the heat transfer path connecting each of the light emitting regions (active layers 4a to 4c) and the heat sink 2 is from one end side to the other end side in the arrangement direction (x direction) of the plurality of light emitting regions (active layers 4a to 4c). By configuring the active layers 4a to 4c having the same specifications to have different temperatures and shifting the wavelengths, the coherence reduction effect can be achieved inexpensively and easily. High-quality semiconductor laser device 1 can be obtained.

In particular, since the submount 3 is formed by arranging base materials (partial base materials 31a to 31c) having different thermal conductivitys along the arrangement direction (x direction), the thermal resistance can be easily changed monotonically.

Alternatively, the submount 3 is formed by stacking base materials having different thermal conductivity (partial base materials 31d and 31e) in the thickness direction (z direction), and the ratio of the thickness of the stacked base materials is set along the arrangement direction. If it is configured to change, the thermal resistance can be easily changed monotonically.

Further, if the submount 3 is configured so that the thickness changes along the arrangement direction, the thermal resistance can be easily changed monotonically by simple processing such as polishing.

Further, the submount 3 has a cavity 3sc or a plurality of light emitting regions (active layer) that advance in parallel to the facing surface 3fe with respect to the semiconductor laser chip 5 in the intermediate portion in the thickness direction, which has a different form depending on the position in the arrangement direction. In the intermediate portion of the regions P4a to P4c where each of 4a to 4c) is projected, the surface 3fe facing the semiconductor laser chip 5 is directed toward the opposite surface (facing surface 3fc) and extends along the traveling direction of light. If the cavity 3st is configured to be formed, the heat resistance can be easily changed monotonically by the inhibition of heat conduction in the lateral direction (in the xy plane) in the submount 3 or by the bypass of the heat path. Can be made to.

Further, the semiconductor laser chip 5 is bonded to the submount 3 at a biased position protruding from one end side, and the submount 3 is bonded to the heat sink 2 at a biased position protruding from one end side. If it is configured as such, the thermal resistance can be easily monotonically changed only by adjusting the joining position without changing the configuration of the member itself.

1: Semiconductor laser device, 2: Heat sink, 2fs: Facing surface, 3: Submount, 31: Substrate, 31a to 31e: Partial substrate, 32c, 32e: Metallized layer, 3fc: Facing surface, 3fe: Facing surface, 3sc: Cavity, 3st: Cavity, 4: Active layer group, 4a-4c: Active layer (light emitting region), 5: Semiconductor laser chip, 5ft: Facing surface, 51: Laminated body, 52b: Bottom electrode, 52t: Top electrode , 53b, 53t: Plating layer, 6, 7: Bonding material, P4a to P4b: Area, R3c: Processing area, R3e: Processing area, R5t: Processing area, W ₃ : Overhang amount, W ₅ : Overhang amount.

Claims (8)

A plate-shaped semiconductor laser chip in which a plurality of light emitting regions extending along the traveling direction of light are arranged at intervals in a direction perpendicular to the traveling direction.
The submount bonded to the semiconductor laser chip and
A heat sink bonded to a surface opposite to the surface to which the semiconductor laser chip of the submount is bonded is provided.
It is characterized in that the thermal resistance of the heat transfer path connecting each of the plurality of light emitting regions and the heat sink is monotonically decreased or monotonically increased from one end side to the other end side in the arrangement direction of the plurality of light emitting regions. Semiconductor laser device. The semiconductor laser device according to claim 1, wherein the thickness of the heat sink is constant from one end side to the other end side in the arrangement direction of the plurality of light emitting regions. The semiconductor laser device according to claim 1 or 2, wherein the submount is formed by arranging substrates having different thermal conductivitys along the arrangement direction. The submount is formed by stacking base materials having different thermal conductivitys in the thickness direction, and the ratio of the thicknesses of the stacked base materials changes along the arrangement direction according to claim 1 or 2. The semiconductor laser device according to 2. The semiconductor laser device according to any one of claims 1 to 4, wherein the submount has a thickness that changes along the arrangement direction. On the submount, a cavity that advances parallel to the surface facing the semiconductor laser chip at an intermediate portion in the thickness direction, which has a different morphology depending on the position in the arrangement direction, or each of the plurality of light emitting regions is projected. From claim 1, a cavity is formed in the middle portion of the region, which advances from the surface facing the semiconductor laser chip toward the surface opposite to the surface and extends along the traveling direction of the light. 4. The semiconductor laser device according to any one of 4. The semiconductor laser chip is bonded to the submount at a biased position protruding from the one end side, and the submount is bonded to the heat sink at a biased position protruding from the one end side. The semiconductor laser apparatus according to any one of claims 1 to 6, wherein the semiconductor laser apparatus is provided. The semiconductor laser chip is joined at a position biased in the arrangement direction with respect to the submount until at least a part of the projection region toward the submount from one of the plurality of light emitting regions protrudes from the submount. The semiconductor laser apparatus according to claim 7, wherein the semiconductor laser apparatus is used.

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