Multibeam semiconductor laser element and semiconductor laser device

Abstract

To provide a semiconductor laser with minimal differences in characteristics between beams. [Solution] The multi-beam semiconductor laser element 100 includes a plurality of laser waveguides 200_1 to 200_4 formed in the laser region 902. Each laser waveguide 200 has a stripe-shaped power supply electrode 150. Power supply pads Pe are formed in pad regions 904 and 906. Connecting wiring Lc connects the corresponding laser waveguides 200 and power supply pads Pe to each other. The heat dissipation portion 182 covers N (2 ≤ N ≤ M) of the M laser waveguides 200 in the first direction, and is insulated from all of the power supply electrodes of the N laser waveguides 200 in the second direction.

Description

Technical Field

[0001] The present disclosure relates to a multi-beam semiconductor laser device.

Background Art

[0002] Semiconductor lasers are used as light sources in electronic devices such as printers and head-mounted displays (HMDs). In order to cope with the increasing resolution of such electronic devices that handle images, a multi-beam semiconductor laser device in which a plurality of laser waveguides are formed in one semiconductor laser device is adopted.

[0003] In order to miniaturize lenses and MEMS mirrors, it is required to narrow the beam pitch. When the beam pitch becomes narrower than the width of the pad (also referred to as a pad electrode or an electrode pad), it is necessary to form the pad close to the wire bonding (WB) region at the end of the chip (semiconductor substrate).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to enable independent driving of a plurality of laser waveguides (emitters), a structure is adopted in which an interlayer insulating film is partially formed on the emitter, and electrodes are formed so as to straddle other emitters from the ridge to the WB region provided at the chip end.

[0006] In this structure, thermal crosstalk between adjacent emitters causes a temperature difference between the centrally located emitter and the outerly located emitters, resulting in variations in characteristics such as wavelength and optical output due to the temperature difference between emitters. In response to this, Patent Document 1 proposes a technique that reduces wavelength variations between emitters even when they are simultaneously lit by adjusting the heat dissipation of each emitter by opening the interlayer insulating film and changing the area in which the first electrode is exposed for each emitter.

[0007] As a result of various studies conducted by the present inventors regarding multi-beam semiconductor lasers, the following problems were identified.

[0008] As described in Patent Document 1, in a structure where the heat dissipation performance is adjusted for each emitter, it has been found that when each beam is lit independently, differences in light output and wavelength occur for each beam even under equivalent driving conditions. This is because the structure itself, which was designed to eliminate variations in characteristics between emitters during simultaneous operation, results in differences in the thermal resistance of each emitter. For example, in display applications, it is required that there be no differences in characteristics between beams not only during simultaneous operation but also when each beam is lit independently, which poses a significant practical challenge.

[0009] Some aspects of this disclosure have been made in view of such problems, and one exemplary objective is to provide a semiconductor laser with small differences in characteristics between beams. [Means for solving the problem]

[0010] A multibeam semiconductor laser element in one aspect of the present disclosure comprises a plurality of M (M≧2) laser waveguides formed adjacent to each other in a first direction in a laser region on a substrate, each laser waveguide having a stripe-shaped power supply electrode whose longitudinal side is in a second direction perpendicular to the first direction, a power supply pad formed in a pad region adjacent to the laser region in the first direction and corresponding to each laser waveguide, and connecting wiring connecting the power supply electrode and the power supply pad. The multibeam semiconductor laser element comprises a heat dissipation portion of metal formed on N (2≦N≦M) adjacent laser waveguides out of the M laser waveguides, separated by an insulating film so as not to conduct in the stacking direction to any of the power supply electrodes of the N laser waveguides.

[0011] Furthermore, any combination of the above components, or any substitution of components or expressions between methods, apparatus, systems, etc., are also valid as embodiments of the present invention or this disclosure. Moreover, the description in this section (means for solving the problem) does not describe all the indispensable features of the present invention, and therefore, subcombinations of these described features may also constitute the present invention. [Effects of the Invention]

[0012] According to certain aspects of this disclosure, the difference in characteristics between beams can be reduced. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of a semiconductor laser element according to an embodiment. [Figure 2] Figure 1 is a plan view of a semiconductor laser element. [Figure 3] Figure 2 shows cross-sectional views of the semiconductor laser device along lines A-A' and BB. [Figure 4] This diagram illustrates the manufacturing method of the semiconductor laser element shown in Figure 1. [Figure 5] This is a plan view of a semiconductor laser element according to Modification Example 1. [Figure 6] Figure 5 is a diagram illustrating the manufacturing method of a semiconductor laser element. [Figure 7] It is a plan view of a semiconductor laser element according to Modification 2. [Figure 8] It is a diagram showing several modification examples of the layout of the metal layer. [Figure 9] It is a diagram showing another modification example of the layout of the metal layer. [Figure 10] It is a plan view of a semiconductor laser element according to Modification 3. [Figure 11] It is a cross-sectional view of a laser device including a semiconductor laser element.

Embodiments for Carrying Out the Invention

[0014] (Overview of Embodiment) The overview of some exemplary embodiments of the present disclosure will be described. This overview is for the purpose of a preface to the detailed description described later or for a basic understanding of the embodiments. This overview simplifies and explains some concepts of one or more embodiments, and does not limit the scope of the invention or the disclosure. Also, this overview is not an all-inclusive overview of all possible embodiments, and does not limit essential components of the embodiments. For convenience, "one embodiment" may be used to refer to one embodiment (example or modification) or a plurality of embodiments (examples or modifications) disclosed in this specification.

[0015] A multi-beam semiconductor laser element according to one embodiment includes a plurality of M (M≧2) laser waveguides formed adjacent to each other in a first direction in a laser region on a substrate. Each laser waveguide has a stripe-shaped power supply electrode having a longitudinal direction in a second direction perpendicular to the first direction, and is formed in a pad region adjacent to the laser region in the first direction. The multi-beam semiconductor laser element includes a power supply pad corresponding to each laser waveguide, and a connection wiring connecting the power supply electrode and the power supply pad. Among the M laser waveguides, the multi-beam semiconductor laser element includes a heat dissipation portion of metal formed with an insulating film so as not to be electrically conductive in the stacking direction with respect to any of the power supply electrodes of the N (2≦N≦M) adjacent laser waveguides.

[0016] According to this configuration, N laser waveguides (emitters) are thermally coupled through a common heat dissipation portion of the metal layer. The N laser waveguides will have equivalent heat dissipation paths, and the heat dissipation performance can be improved. The thermal resistance felt by each laser waveguide is the combined resistance of the thermal resistance derived from the current injection region and the thermal resistance of the heat dissipation portion. The former is different for each laser waveguide, but the latter is common to the laser waveguides. Therefore, compared with a structure having only the former, the difference in heat dissipation performance among the N laser waveguides can be reduced. Thereby, the difference in beam characteristics can be reduced between the case where the N laser waveguides emit light simultaneously and the case where one of the N laser waveguides emits light.

[0017] The influence of the thermal resistance of the heat dissipation portion can be increased by increasing the length L of the heat dissipation portion. Specifically, it is desirable that L be longer than 1 / 2 of the length Ls of the substrate in the second direction.

[0018] Note that the shape of the heat dissipation portion is arbitrary and is not limited to a rectangle. In this case, the length L of the heat dissipation portion may be considered as the total sum of the lengths in the second direction of the portions straddling two or more waveguides.

[0019] In one embodiment, M = N may be satisfied. Thereby, the difference in beam characteristics of all the laser waveguides can be reduced.

[0020] In one embodiment, when the thickness of the substrate is Ds and the width in the first direction of the range where M laser waveguides are formed is D, the length W in the first direction of the heat dissipation portion may be W > D + 2×Ds.

[0021] In one embodiment, the heat dissipation portion may be formed by being divided into a plurality of regions in the second direction.

[0022] In one embodiment, the thickness of the heat dissipation portion may be equal to or greater than the thickness of the connection wiring. Thereby, the thermal resistance can be reduced and the heat dissipation function can be enhanced.

[0023] In one embodiment, the position of the center of gravity of the heat dissipation portion in the second direction may be biased toward the exit end face side than the center of the substrate in the second direction. Since heat tends to concentrate toward the exit end face side, heat can be effectively dissipated by forming the heat dissipation portion near this heat-concentrating area.

[0024] In one embodiment, the heat dissipation portion may be positioned on the exit end face side of the multiple connecting wires in the second direction.

[0025] In one embodiment, the heat dissipation portion may be electrically connected to one of a plurality of connecting wires. This allows the heat dissipation portion to be formed simultaneously with the formation of the power supply pad by plating.

[0026] In one embodiment, the ratio of the difference in thermal resistance among the N laser waveguides that are thermally coupled by the heat dissipation portion among the M laser waveguides may be 10% or less.

[0027] In one embodiment, a protective film formed on the upper side of the heat dissipation portion may be further provided.

[0028] A semiconductor laser apparatus according to one embodiment may include a submount and any of the above-described multi-beam semiconductor laser elements mounted junction-up on the submount.

[0029] (Embodiment) The present disclosure will be described below with reference to the drawings, based on preferred embodiments. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted where appropriate. Furthermore, the embodiments are illustrative and not limiting, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure.

[0030] The dimensions (thickness, length, width, etc.) of each component shown in the drawing may be enlarged or reduced as appropriate for ease of understanding. Furthermore, the dimensions of multiple components do not necessarily represent their relative sizes; even if component A is depicted as thicker than component B in the drawing, component A may actually be thinner than component B.

[0031] (Embodiment) Figure 1 is a perspective view of a semiconductor laser element 100 according to an embodiment. The semiconductor laser element 100 is an end-face emitting type semiconductor laser element and is a multi-beam semiconductor laser having a plurality of M (M≧2) emitters. In this embodiment, the number of emitters M is 4.

[0032] The semiconductor laser element 100 comprises a substrate 110 and a laminated structure 120 formed on the substrate 110. The laminated structure 120 includes an N-type semiconductor layer 122, an emissive layer (active layer) 124, and a P-type semiconductor layer 126, which are sequentially laminated on the substrate 110 by epitaxial growth. The emissive layer 124 includes an N-type guide layer (lower guide layer), an active layer consisting of a quantum well layer, and a P-type guide layer (upper guide layer). The materials of the substrate 110 and the laminated structure 120 can be selected according to the required oscillation wavelength and are not particularly limited in this disclosure.

[0033] The semiconductor laser element 100 has a central laser region 902 and pad regions 904 and 906. In the laser region 902, M adjacent laser waveguides 200_1 to 200_M are formed in the first direction (x direction). Each laser waveguide 200 has a stripe structure extending in a second direction (z direction) perpendicular to the first direction (x direction), and emits a beam in the z direction.

[0034] A waveguide structure for confining light is formed in the laminated structure 120, and the cleavage surfaces at both ends of this waveguide structure act as mirrors, forming a Fabry-Perot type laser waveguide 200. In this example, four laser waveguides 200_1 to 200_4 are formed, and beams BM1 to BM4 are emitted in the z direction from the exit end face (front end face) S1. The exit end face S1 and rear end face S2 of each laser waveguide 200 are coated to give a desired reflectivity.

[0035] The laser waveguide 200 may be an external resonator type laser, a distributed Bragg Reflector (DBR) laser, or a distributed feedback (DFB) laser.

[0036] The waveguide structure can be, for example, an embedded ridge waveguide.

[0037] Alternatively, the waveguide structure may be a CSP (Channeled Substrate Planar) structure in which grooves are formed in the substrate 110 along the waveguide, and the thickness of the N-type semiconductor layer 122 in the groove portion is relatively thicker.

[0038] While embedded ridge structures and CSP structures are waveguide structures that utilize refractive index distributions, this disclosure is not limited to these, and gain waveguide structures that utilize gain distributions may also be used. These structures can be understood as both optical confinement structures and current constriction structures.

[0039] In order to independently drive the laser waveguides 200_1 to 200_M, they must be electrically isolated. For this purpose, insulating means such as a separation groove is formed between two adjacent laser waveguides 200.

[0040] A contact insulating film (not shown) is formed on the upper surface of each laser waveguide 200. Rectangular openings are formed in the contact insulating film on the upper surfaces of laser waveguides 200_1 to 200_M, with the z-direction being the longitudinal direction. Power supply electrodes (P-side electrodes) 150 are formed along these openings. To enable the laser waveguides 200 to be driven independently, the power supply electrodes 150 are electrically insulated from each other. In this embodiment, the power supply electrodes 150 are stripe-shaped electrodes extending along the z-direction on the upper surface of the laser waveguide 200.

[0041] An N-side electrode 152 is formed on the back surface of the laser waveguide 200.

[0042] A metal layer 180 is formed on top of multiple laser waveguides 200 to supply power to the laser waveguides 200. Specifically, the metal layer 180 includes multiple power supply pads (hereinafter simply referred to as pads) Pe1 to Pe4 corresponding to the multiple laser waveguides 200_1 to 200_4, and multiple connection wirings Lc1 to Lc4.

[0043] Multiple pads Pe1 to Pe4 are formed in the laser region 902 and adjacent pad regions 904 and 906 in the x-direction. Bonding wires are connected to pads Pe1 to Pe4 in the case of junction-up mounting, and solder is connected in the case of junction-down mounting.

[0044] Each connection wire Lci (i=1,2,3,4) electrically connects the power supply electrode 150 of the corresponding laser waveguide 200_i to the corresponding pad Pi.

[0045] Of the multiple laser waveguides 200_1 to 200_4, the two inner ones (200_2 and 200_3) have connecting wires Lc2 and Lc3 that cross the power supply electrodes 150 of the outer laser waveguide 200. Specifically, connecting wire Lc2 crosses the power supply electrode 150_1 of laser waveguide 200_1. Similarly, connecting wire Lc3 crosses the power supply electrode 150_4 of laser waveguide 200_4.

[0046] The insulating film 170 is formed to include the points where the connecting wiring Lc and the power supply electrode 150 intersect, thereby ensuring electrical insulation between the connecting wiring Lc2 and the power supply electrode 150_1, and between the connecting wiring Lc3 and the power supply electrode 150_4.

[0047] In this embodiment, the insulating film 170 covers a wide area including not only the formation range of the connecting wirings Lc2 and Lc3, but also the formation range of the connecting wirings Lc1 and Lc4. In this embodiment, the insulating film 170 is formed in a single rectangular region that includes a portion of the multiple power supply electrodes 150_1 to 150_4 contained within the laser region 902.

[0048] The insulating film 170 has openings OPi at the connection points between the corresponding connection wiring Lci and the power supply electrodes 150_i (i=1~4). In this embodiment, openings OP1 to OP4 are formed in the insulating film 170. Connection wiring Lc1 and power supply electrode 150_1 are electrically connected via opening OP1, connection wiring Lc2 and power supply electrode 150_2 are electrically connected via opening OP2, connection wiring Lc3 and power supply electrode 150_3 are electrically connected via opening OP3, and connection wiring Lc4 and power supply electrode 150_4 are electrically connected via opening OP4.

[0049] Organic materials such as polyimide can be used as the material for the insulating film 170. Polyimide has the advantage of being able to fill in irregularities in the substrate and easily create a flat surface, thus flattening the connecting wiring Lc and improving the coverage of the film. In addition, it has toughness and high durability against external forces, making it less prone to damage such as cracks, and can improve the electrical insulation between electrodes.

[0050] The metal layer 180 includes a heat dissipation portion 182 that covers N of the M laser waveguides 200_1 to 200_4 in the x-direction (first direction). In this example, N=M, and the heat dissipation portion 182 covers all of the laser waveguides 200_1 to 200_4. The heat dissipation portion 182 is insulated from all of the power supply electrodes 150 of the N laser waveguides 200_1 to 200_4 in the z-direction (second direction). Although this embodiment is described as N=M, the number of power supply pads and connection wires does not have to be equal to the number of laser waveguides.

[0051] Figure 2 is a plan view of the semiconductor laser element 100 shown in Figure 1. The length L of the heat dissipation portion 182 in the second direction (z direction) is longer than half the length Ls of the substrate 110 in the second direction. In other words, the heat dissipation portion 182 occupies a wider area than half of the chip with respect to the second direction.

[0052] Furthermore, it is preferable that the length W of the heat dissipation portion 182 in the first direction is longer than the width D in the first direction of the area where N laser waveguides 200_1 to 200_4 are formed. More preferably, when the thickness of the substrate 110 is Ds, W ≥ D + 2 × Ds It is preferable that the following conditions be met.

[0053] Figure 3 is a cross-sectional view of the semiconductor laser element 100 in Figure 2, taken along lines A-A' and BB. The thickness T of the heat dissipation portion 182 may be equal to the thickness tc of the connecting wiring Lc, but it is more preferable that it be thicker than the thickness tc. By increasing the thickness of the heat dissipation portion 182, the thermal resistance can be reduced.

[0054] A protective film (not shown) may be formed on the upper side of the heat dissipation portion 182. This protects the heat dissipation portion 182 from oxidation and contamination, improving long-term reliability. The protective film can be formed using materials such as SiO2, Al2O3, AlN, SiN, TiO2, and Ta2O5 by sputtering or chemical vapor deposition.

[0055] The above describes the configuration of the semiconductor laser element 100.

[0056] N laser waveguides (emitters) are thermally coupled via a common heat dissipation portion 182 of the metal layer 180. This ensures that the N laser waveguides 200_1 to 200_N have equivalent heat dissipation paths, improving heat dissipation. The thermal resistance felt by each laser waveguide 200_1 to 200_N is the combined resistance of the thermal resistance originating from the current injection region and the thermal resistance of the heat dissipation portion 182. The former differs for each laser waveguide 200, but the latter is common to all laser waveguides 200. Therefore, by making the length L of the heat dissipation portion 182 larger than the length Ls / 2 of the substrate 110, the influence of the latter can be relatively increased, reducing the difference in heat dissipation. This reduces the difference in beam characteristics between the case where all N laser waveguides 200_1 to 200_N are emitted simultaneously and the case where only one of the N laser waveguides 200_1 to 200_N is emitted.

[0057] It is preferable that the difference between the average thermal resistance of the N laser waveguides 200_1 to 200_N, which are thermally coupled by the heat dissipation portion 182 among the M laser waveguides 200_1 to 200_M, and the thermal resistance of each laser waveguide is 10% or less. This makes it possible to make the beam characteristics of each of the N laser waveguides 200_1 to 200_N more uniform.

[0058] Furthermore, as shown in Figure 2, the position z0 of the center of gravity G of the heat dissipation portion 182 in the second direction (z direction) is biased toward the exit end face S1 side than the center z1 of the substrate 110 in the second direction. Since the heat of the semiconductor laser element 100 tends to concentrate toward the exit end face S1 side, the heat dissipation portion 182 can be suitably dissipated by forming it near this heat-concentrating area. From this viewpoint, the heat dissipation portion 182 is preferably positioned toward the exit end face S1 side than the M connection wirings Lc1 to Lc4 in the second direction (z direction).

[0059] Figure 4 illustrates the manufacturing method of the semiconductor laser element 100 shown in Figure 1. A stacked structure 120 is formed on a semiconductor wafer which will serve as the substrate 110, and then a ridge structure is formed on the P-type semiconductor layer 126. Power supply electrodes 150_1 to 150_4 are formed on the upper side of this ridge structure (S100).

[0060] Next, an insulating film 170 is formed (S102), and openings OP1 to OP4 are formed in the insulating film 170 (S104). Then, the metal layer 180, which consists of connecting wiring Lc1 to Lc4 and a heat dissipation portion 182, is formed (S106). Then, pads Pe1 to Pe4 are formed by plating (S108). In the wafer state, the chips are continuous in the vertical and horizontal directions of the drawing, so the power supply electrode 150 is formed continuously in the vertical direction of the drawing. The current necessary for the plating process is supplied to the connecting wiring Lc1 to Lc4 via this power supply electrode 150, and pads Pe1 to Pe4 are formed.

[0061] The above is an example of a method for manufacturing the semiconductor laser element 100. However, the method for manufacturing the semiconductor laser element 100 is not limited to that described here.

[0062] Next, we will explain a modified example of the semiconductor laser element 100.

[0063] Figure 5 is a plan view of a semiconductor laser element 100A according to Modification 1. In this semiconductor laser element 100A, part or all of the heat dissipation portion 182 (referred to as the thick film portion 184) is thickened by plating, similar to the pad Pe. By thickening the heat dissipation portion 182, the thermal resistance can be reduced, and a more significant effect can be obtained.

[0064] In the modified example 1, the semiconductor laser element 100A is arranged in a wafer state with identical multi-beam semiconductor laser elements 100A side by side in the second direction (z-direction). At this time, the heat dissipation portion 182 of one multi-beam semiconductor laser element 100A and at least one of the connecting wirings Lc1 to Lc4 of the adjacent multi-beam semiconductor laser element 100A (Lc1, Lc3 in this example) are continuous. This means that in the wafer state before the semiconductor laser element 100A is chipped, the heat dissipation portion 182 and the connecting wirings Lc1 to Lc4 are electrically connected across the chip boundary.

[0065] Specifically, the metal layer 180 includes a connecting portion 186 extending from the end of the heat dissipation portion 182 to the exit end face S1. The metal layer 180 also includes a connecting portion 188 extending from at least one of the connecting wires Lc1 to Lc4 (Lc1, Lc3 in this example) to the rear end face S2.

[0066] Next, the manufacturing method of the semiconductor laser element 100A shown in Figure 5 will be explained. Figure 6 is a diagram illustrating the manufacturing method of the semiconductor laser element 100A shown in Figure 5. The manufacturing method of the semiconductor laser element 100A is the same as that of the semiconductor laser element 100 in Figure 1 for steps S100, S102, and S104 in Figure 4. In step S110 in Figure 6, a metal layer 180 is formed, and this metal layer 180 includes connection wiring Lc1 to Lc4, a heat dissipation portion 182, and connection portions 186 and 188.

[0067] In the subsequent plating process S112, pads Pe1 to Pe4 are formed on top of the connection wirings Lc1 to Lc4. Since the heat dissipation portion 182 is electrically connected to the connection wirings Lc1 and Lc3 of the adjacent chip, the heat dissipation portion 182 is also plated, increasing its thickness.

[0068] The above describes the manufacturing method for the semiconductor laser element 100A.

[0069] Figure 7 is a plan view of the semiconductor laser element 100B according to Modification 2. Similar to Modification 1, the thick film portion 184 of the heat dissipation portion 182 of this semiconductor laser element 100B is thickened by plating, similar to the pad Pe. By thickening the heat dissipation portion 182, the thermal resistance can be reduced, and a more significant effect can be obtained.

[0070] In the modified example 2, the semiconductor laser elements 100B are arranged side by side in the wafer state in the first direction (x direction). At this time, the heat dissipation portion 182 of one multi-beam semiconductor laser element 100B and the heat dissipation portion 182 of the adjacent multi-beam semiconductor laser element 100B are continuous. This means that in the wafer state before the semiconductor laser elements 100B are chipped, the heat dissipation portions 182 are electrically connected across the chip boundary.

[0071] Specifically, the metal layer 180 includes a connecting portion 190 extending from the end of the heat dissipation portion 182 to side E1 of the semiconductor laser element 100B, and a connecting portion 192 extending from the end of the heat dissipation portion 182 to side E2 of the semiconductor laser element 100B.

[0072] The manufacturing method for the semiconductor laser element 100B shown in Figure 7 is explained. In the wafer state, multiple chips form a continuous metal portion in the x direction, and the heat dissipation portion 182 and the connection portions 190 and 192 form a single conductor in the x direction. By passing current through this conductor, the top of the heat dissipation portion 182 is plated, increasing its thickness.

[0073] Figure 8 shows several variations (100a, 100b, 100c) of the layout of the metal layer 180. In the semiconductor laser element 100a shown on the left, the width W of the heat dissipation portion 182 can be arbitrarily designed within the range where W > D, and more preferably within the range where W > D + 2 × Ds.

[0074] In the semiconductor laser element 100b shown in the center, the heat dissipation portion 182 is electrically connected within the chip to one of the multiple connection lines Lc1 to Lc4 (Lc1 in this example) via a connection portion 194.

[0075] In the semiconductor laser element 100c shown on the right, pads Pe1 to Pe4 are formed on one side of the chip.

[0076] FIG. 9 is a diagram showing another modification example (100d, 100e, 100f) of the layout of the metal layer 180. In the semiconductor laser element 100d shown on the left, with respect to the z direction, the connection wirings Lc1 and Lc4 are formed close to the emission end face S1, and the heat dissipation portion 182 is formed in the center.

[0077] In the semiconductor laser element 100e shown in the center, the heat dissipation portion 182 is formed close to the emission end face S1. That is, the center of gravity of the heat dissipation portion 182 exists on the emission end face S1 side rather than the center position of the chip.

[0078] In the semiconductor laser element 100f shown on the right, the heat dissipation portion 182 is formed by being divided into a plurality of regions in the z direction. When the lengths in the z direction of the respective plurality of regions are A1, A2, A3..., it is only necessary to satisfy A1 + A2 + A3 +... > Ls / 2.

[0079] FIG. 10 is a plan view of the semiconductor laser element 100C according to Modification Example 3. In the previous description, the heat dissipation portion 182 covered all the laser waveguides 200_1 to 200_4 and N = M, but the present disclosure is not limited thereto. When uniformity of characteristics is required among specific N of the plurality of laser waveguides 200, the heat dissipation portion 182 may be formed so as to cover them, and N < M may also be possible. In the modification example of FIG. 10, N = 2, and the metal layer 180 includes a heat dissipation portion 182 that covers the laser waveguide 200_1 and the laser waveguide 200_2 in the x direction. In this case, when the width of the range in which the laser waveguide 200 for which uniformity of characteristics is required is formed is D, the width W of the heat dissipation portion 182 only needs to satisfy W ≧ D, and more preferably, it is good to satisfy W > D + 2×Ds. Ds is the thickness of the substrate 110.

[0080] FIG. 11 is a cross-sectional view of a semiconductor laser device 400 including the semiconductor laser element 100. The semiconductor laser device 400 is of a To-CAN package type and includes an LD chip 410, a submount 420, a metal stem 430, a metal cap 440, a glass window 450, and leads 460 to 463.

[0081] The LD chip 410 is the semiconductor laser element 100 described above, and is equipped with a plurality of independently drivable laser waveguides 200, and is configured to emit a plurality of beams from its front end face. The LD chip 410 is junction-up mounted on a submount 420, and the submount 420 is fixed to a metal stem 430.

[0082] The metal cap 440 covers the LD chip 410 from the side and also supports and secures the glass window 450.

[0083] Multiple leads 460-464 penetrate the metal stem 430 in an insulated manner from the metal stem 430. Each pad Pe formed on the semiconductor laser element 100, which is the LD chip 410, is connected to a corresponding one of the multiple leads 461-463 via a bonding wire 320. The N-side electrode of the semiconductor laser element 100 is also connected to lead 460 via a bonding wire 322 (or in another manner without using the bonding wire 322).

[0084] (modified version) In this embodiment, the number M of laser waveguides 200 is set to 4, but the number M is not limited to 4 and may be 2, 3, or 5 or more.

[0085] In this embodiment, the case in which the semiconductor laser element 100 is mounted using a junction-up configuration has been described, but it is also possible to mount a chip having the same configuration using a junction-down configuration. In this case, the solder applied to the electrodes formed on the support substrate during mounting serves as the means of electrical connection.

[0086] The embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted in the embodiments, without departing from the spirit of the present invention as defined in the claims. [Explanation of symbols]

[0087] 100 semiconductor laser elements 902 Laser Region 904,906 pad area 110 circuit boards 120 Laminated structure 122 N-type semiconductor layer 124 Emitting layer 126 P-type semiconductor layer Pe Pad OP opening 150 Power supply electrodes 170 insulating film 180 metal layer 182 Heat dissipation part 184 Thick film part 186, 188, 190, 192 Connection part 200 Laser Waveguides 320 Bonding Wire 400 Semiconductor laser devices 410 LD chips 420 Submount 430 Metal Stem 440 Metal cap 450 glass windows 460, 461, 462, 463 Reeds

Claims

1. A multi-beam semiconductor laser element, A plurality of (M: M≧2) laser waveguides are formed adjacent to each other in a first direction in a laser region on a substrate, and each laser waveguide has a stripe-shaped power supply electrode whose longitudinal side is in a second direction perpendicular to the first direction. A power supply pad is formed in the laser region and the pad region adjacent to the first direction, and each laser waveguide is corresponding to a power supply pad, The system includes a connecting wire that connects the power supply electrode and the power supply pad, A multibeam semiconductor laser element characterized by having a metal heat dissipation portion formed on N adjacent (2 ≤ N ≤ M) laser waveguides among the M laser waveguides, separated by an insulating film so as not to conduct electricity in the stacking direction to any of the power supply electrodes of the N laser waveguides.

2. The multi-beam semiconductor laser element according to claim 1, characterized in that the length L of the heat dissipation portion in the second direction is longer than half the length Ls of the substrate in the second direction.

3. The multibeam semiconductor laser element according to claim 1, characterized in that the relationship between the number of laser waveguides M and the number of adjacent laser waveguides N is M = N.

4. When the thickness of the substrate is Ds and the width in the first direction of the area where the M laser waveguides are formed is D, the length W of the heat dissipation portion in the first direction is W > D + 2 × Ds The multi-beam semiconductor laser element according to claim 1, characterized in that it is the same as described in claim 1.

5. The multi-beam semiconductor laser element according to claim 1, characterized in that the heat dissipation portion is formed by dividing it into a plurality of regions with respect to the second direction.

6. The multi-beam semiconductor laser element according to claim 1, characterized in that the thickness of the heat dissipation portion is greater than or equal to the thickness of the connecting wiring.

7. The multi-beam semiconductor laser element according to claim 1, characterized in that the position of the center of gravity of the heat dissipation portion in the second direction is biased toward the exit end face side than the center of the substrate in the second direction.

8. The multi-beam semiconductor laser element according to claim 7, characterized in that the heat dissipation portion is located on the side of the output end face that is greater than the M connection wires in the second direction.

9. The multi-beam semiconductor laser element according to claim 1, characterized in that the heat dissipation portion is electrically connected to one of the N connection wires.

10. The multi-beam semiconductor laser element according to claim 1, characterized in that, of the M laser waveguides, the ratio of the difference in thermal resistance of the N laser waveguides thermally coupled by the heat dissipation portion is 10% or less.

11. The multibeam semiconductor laser element according to claim 1, further comprising a protective film formed on the upper side of the heat dissipation portion.

12. Submount and A multibeam semiconductor laser element according to claim 1 or 2, which is junction-up mounted on the submount, A semiconductor laser device characterized by comprising the following features.

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