Semiconductor laser device

Abstract

The semiconductor laser device includes: a semiconductor laser element having a plurality of mesa portions; and an auxiliary seat having a recessed portion in which a plurality of mesa portions are disposed. The recessed portion is provided with a wiring portion. An electrode corresponding to each mesa portion is electrically connected to the wiring portion via a welding member. The wiring portion includes a first wiring and a second wiring adjacent to each other and electrically separated from each other. The first reference surface of the semiconductor laser element is in surface contact with the second reference surface of the auxiliary seat. A distance from a first base end portion of the first mesa portion corresponding to the first wiring to a second base end portion of the second mesa portion corresponding to the second wiring is longer than a length of a contact region of the mesa portion.

Description

Technical Field

[0001] The present disclosure relates to a semiconductor laser device. Background Art

[0002] Conventionally, an end-emission type semiconductor laser element is known. For example, Patent Document 1 discloses a structure in which the back side of a semiconductor laser element having a plurality of channels (light-emitting points) is mounted on a support member in a junction-up manner. In addition, conventionally, as a mounting method other than the junction-up method, a junction-down method in which the surface of a semiconductor laser element is mounted on a support member is also known.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-125614 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the conventional mounting method as described above, when the surface or back surface of a semiconductor laser element is mounted on a support member via a soldering member by reflow soldering or the like, there is a problem that the thickness of the soldering member is uneven, causing deviations in the height positions of multiple light-emitting points.

[0008] Furthermore, when the system is configured to include at least a first channel and a second channel that can drive a plurality of channels independently of each other, it is necessary to reliably prevent a short circuit between the first channel and the second channel.

[0009] Therefore, an object of one aspect of the present disclosure is to provide a semiconductor laser device capable of preventing short circuits between channels configured to be driven independently of each other and performing positional alignment of a plurality of light-emitting points with high precision.

[0010] Means used to solve problems

[0011] The present disclosure includes the following semiconductor laser devices [1] to

[18] . [1]

[0013] A semiconductor laser device, wherein:

[0014] have:

[0015] A semiconductor laser element, comprising: a substrate having a first surface and a second surface located on opposite sides to each other in a first direction; and a plurality of mesa portions having a light emitting end face intersecting a second direction orthogonal to the first direction and formed so as to protrude in the first direction relative to a first reference plane formed on the second surface and extend in the second direction; and

[0016] A support member having: a third surface forming a second reference surface opposite to the first reference surface; and a recessed portion formed on the third surface and provided with a plurality of table portions,

[0017] The mesa portion has: a top surface that faces the bottom surface of the recess; and a pair of side surfaces that are located on opposite sides of each other in a third direction that is orthogonal to the first direction and the second direction.

[0018] A first electrode is provided on the top surface of the mesa portion and is electrically connected to a contact layer provided on the top surface side of the mesa portion.

[0019] The recessed portion is provided with wiring portions at positions corresponding to the plurality of terrace portions.

[0020] The first electrodes corresponding to the plurality of mesa portions are electrically connected to the wiring portion via a welding member.

[0021] The wiring section includes a first wiring and a second wiring arranged adjacent to each other in the third direction and electrically separated from each other,

[0022] The first table portion which is a table portion electrically connected to the first wiring and the second table portion which is a table portion electrically connected to the second wiring are electrically separated by arranging the table portion so that the welding member electrically connected to the first wiring and the welding member electrically connected to the second wiring do not contact each other.

[0023] The first reference surface is in surface contact with the second reference surface,

[0024] A distance in the third direction from a first base end portion which is a boundary between a side surface of the first terrace portion on a side where the second terrace portion is located relative to the first terrace portion and the first reference plane to a second base end portion which is a boundary between a side surface of the second terrace portion on a side where the first terrace portion is located relative to the second terrace portion and the first reference plane is longer than a length in the third direction of a contact region in the contact layer that is in contact with the first electrode.

[0025] In the semiconductor laser device, the first reference surface of the semiconductor laser element is in surface contact with the second reference surface of the support member. Thus, it is possible to align the positions of a plurality of light-emitting points (for example, the center of the light-emitting end surface in the first direction) with respect to the second reference surface of the support member with high precision. In addition, the semiconductor laser device has a first stage portion and a second stage portion that are electrically separated from each other (that is, configured to be driven independently of each other) and arranged adjacent to each other. Here, the amount of welding components required (for example, the width of the welding components in the third direction) may change according to the width of the contact area (the length in the third direction), but in the semiconductor laser device, the interval between the first stage portion and the second stage portion (that is, the distance from the first base end portion to the second base end portion in the third direction) is longer than the width of the contact area. Thus, it is possible to fully ensure the interval between the first stage portion and the second stage portion for the amount of welding components required according to the width of the contact area. As a result, when the semiconductor laser element is mounted on the support member by reflow soldering, it is possible to appropriately prevent the welding components corresponding to the first stage portion and the welding components corresponding to the second stage portion from melting and contacting each other. Therefore, according to the semiconductor laser device, short circuits between channels configured to be driven independently of each other can be prevented, and the positions of a plurality of light-emitting points can be aligned with high accuracy. [2]

[0027] The semiconductor laser device according to [1], wherein

[0028] The recess has: a first recess having a first stage portion; and a second recess having a second stage portion.

[0029] The length of the second reference surface of the partition wall portion formed between the first recess and the second recess and extending in the second direction to separate the first recess and the second recess is longer in the third direction than the length of the contact region in the third direction.

[0030] According to the above structure, by arranging the first platform portion and the second platform portion in different recesses (the first recess and the second recess) and sufficiently ensuring the width of the partition wall portion between the first recess and the second recess, it is possible to appropriately prevent the welding component corresponding to the first platform portion (or the second platform portion) that melts during reflow from crossing the partition wall portion and short-circuiting with the welding component corresponding to the second platform portion (or the first platform portion). [3]

[0032] The semiconductor laser device according to [1] or [2], wherein:

[0033] The recessed portion is composed of a plurality of recessed portions each of which is individually provided with a plurality of table portions.

[0034] A partition wall portion is provided between adjacent recessed portions. The partition wall portion extends in the second direction, has a predetermined length in the third direction, and has a second reference surface.

[0035] According to the above structure, compared with a structure including a single recessed portion provided with two or more mesa portions, short circuits between adjacent mesa portions can be appropriately prevented, and the reliability of independent driving of multiple channels can be improved. In addition, the contact area between the first reference plane and the second reference plane can be increased in the partition wall portion provided between the recessed portions, thereby reducing the stress of the semiconductor laser element (mainly the substrate), and suppressing the occurrence of bending of the semiconductor laser element. In particular, when the length of the substrate in the third direction is lengthened by arranging a plurality of mesa portions in the third direction, bending of the substrate is easily generated in the third direction. The above structure is particularly effective in such a case. [4]

[0037] A semiconductor laser device according to any one of [1] to [3], wherein:

[0038] A single second electrode common to the plurality of mesa portions is provided on the first surface.

[0039] According to the above structure, by making the electrode component (second electrode) arranged on the back side (first surface) of the substrate of the semiconductor laser element shared among multiple table portions, the number of wires connected to the electrode component by wire bonding can be reduced, thereby suppressing damage to the semiconductor laser element caused by wire bonding. [5]

[0041] A semiconductor laser device according to any one of [1] to [4], wherein:

[0042] The recessed portion has a first side surface opposite to a side surface of the table portion in the third direction,

[0043] The first side surface is inclined with respect to the bottom surface so that an opening width of the recessed portion of the third surface along the third direction is larger than a width of a bottom surface of the recessed portion along the third direction.

[0044] According to the above configuration, by configuring the first side surface of the recessed portion as an inclined surface that widens from the bottom surface side toward the opening end side, a space for the melted solder member to overflow during reflow can be appropriately ensured in the recessed portion. [6]

[0046] A semiconductor laser device according to any one of [1] to [5], wherein:

[0047] The wiring portion extends from the inside of the recess to the third surface outside the recess.

[0048] According to the above configuration, the electrode on the mesa portion side of the semiconductor laser element can be led out to the surface (third surface) of the base member via the first electrode and the wiring portion, so that the structure for passing current through the semiconductor laser element can be easily mounted. [7]

[0050] The semiconductor laser device according to [6], wherein

[0051] The wiring portion extends from the inside of the recess to the outside of the recess along the second direction,

[0052] The recess has a second side surface intersecting the second direction and on which the wiring portion extends,

[0053] The second side surface is inclined with respect to the bottom surface so that an opening width of the recessed portion of the third surface along the second direction is larger than a width of a bottom surface of the recessed portion along the second direction.

[0054] Assuming that the second side surface is not inclined as described above (for example, when the second side surface is a surface perpendicular to the bottom surface of the recessed portion), the wiring portion is bent in a step-like manner, so that disconnection is likely to occur. On the other hand, by configuring the second side surface as an inclined surface as described above and making the wiring portion follow the inclined second side surface, the wiring portion can be prevented from being bent in a step-like manner and disconnection can be suppressed. [8]

[0056] A semiconductor laser device according to any one of [1] to [7], wherein:

[0057] Each of the plurality of mesa portions has one or more active layers independently provided for each mesa portion.

[0058] According to the above structure, the active layers are spatially separated between the multiple mesa portions, so that the occurrence of optical crosstalk between the mesa portions can be reliably prevented. In addition, when multiple active layers are provided on each mesa portion, each mesa portion can function as a stacked semiconductor laser element and the laser output can be enhanced. [9]

[0060] A semiconductor laser device according to any one of [1] to [8], wherein:

[0061] The wiring section includes a plurality of wirings which are arranged at positions corresponding to the plurality of mesa sections and are electrically separated from each other.

[0062] Any two wirings arranged adjacent to each other in the third direction among the plurality of wirings correspond to the first wiring and the second wiring.

[0063] According to the above structure, between any two adjacent mesa portions, the interval between the mesa portions (i.e., the distance from the first base end portion to the second base end portion in the third direction) is longer than the width of the contact area, thereby preventing short circuits between the channels and enabling multiple mesa portions (channels) to be driven independently.

[10]

[0065] A semiconductor laser device according to any one of [1] to [9], wherein:

[0066] The support member is formed of silicon.

[0067] According to the above structure, the recessed portion can be formed with high precision by, for example, an etching process.

[11]

[0069] A semiconductor laser device according to any one of [1] to

[10] , wherein:

[0070] The support member has a fourth surface connected to the third surface and intersecting the second direction,

[0071] The recessed portion extends to the fourth surface and opens at the fourth surface.

[0072] According to the above configuration, the light emission end surface of each mesa portion arranged in the recess can be exposed to the outside from the portion of the recess opened on the fourth surface, thereby improving the efficiency of extracting light emitted in the second direction from the light emission end surface.

[12]

[0074] A semiconductor laser device according to any one of [1] to

[11] , wherein:

[0075] The third surface is provided with an alignment mark for aligning the semiconductor laser element with respect to the base member.

[0076] According to the above configuration, when the semiconductor laser element is mounted on the mount member, the position of the semiconductor laser element with respect to the mount member can be easily and accurately aligned.

[13]

[0078] A semiconductor laser device according to any one of [1] to

[12] , wherein:

[0079] The thickness of the substrate in the first direction is smaller than the thickness of the seating member in the first direction.

[0080] According to the above configuration, by using a support member thicker than the semiconductor laser element, deformation of the support member relative to the semiconductor laser element (i.e., deformation of the second reference surface) can be appropriately suppressed. As a result, the positions of the plurality of light-emitting points relative to the second reference surface of the support member can be aligned with higher precision.

[14]

[0082] A semiconductor laser device according to any one of [1] to

[13] , wherein:

[0083] The substrate has a fifth surface intersecting the third direction,

[0084] A distance in the third direction from an end of the recessed portion provided at a position closest to the fifth surface in the third direction to the fifth surface is longer than a distance in the first direction from the first reference surface to the top surface of the mesa portion.

[0085] According to the above configuration, the area of ​​the portion where the first reference surface and the second reference surface contact each other can be ensured to be greater than a certain level outside the region where the recess is provided in the third direction in the substrate, thereby improving the support stability of the semiconductor laser element with respect to the mount member.

[15]

[0087] A semiconductor laser device according to any one of [1] to

[14] , wherein:

[0088] Also available:

[0089] an optical element disposed at a position opposed to the semiconductor laser element and the support member in the second direction and guiding light emitted from the light emitting end faces of each of the plurality of mesa portions to the outside; and

[0090] a support substrate that supports the support member and the optical element,

[0091] The support substrate has a first support surface that is in surface contact with a sixth surface of the base member opposite to the third surface and supports the base member, and a second support surface that is in surface contact with the optical element and supports the optical element.

[0092] According to the above structure, the support member on which the semiconductor laser element is mounted and the optical element are supported by making surface contact with the first supporting surface and the second supporting surface of the supporting substrate, so that the height positions of the semiconductor laser element and the optical element (i.e., the height positions of each member based on the supporting surface (the first supporting surface and the second supporting surface) of the supporting substrate can be easily and accurately aligned.

[16]

[0094] The semiconductor laser device according to

[15] , wherein

[0095] The optical element has a light incident surface for incident light emitted from the light emitting end surfaces of the plurality of mesa portions.

[0096] The support member has a fourth surface opposite to the light incident surface,

[0097] The light incident surface is in surface contact with the fourth surface.

[0098] According to the above configuration, by bringing the fourth surface of the support member and the light incident surface of the optical element, which are opposite to each other in the second direction, into surface contact, the distance between the light emitting end surface and the light incident surface in the second direction can be adjusted with high accuracy. That is, when the semiconductor laser element is mounted on the support member, by adjusting the distance from the light emitting end surface to the fourth surface in the second direction, the distance from the light emitting end surface to the light incident surface can be adjusted.

[17]

[0100] A semiconductor laser device according to any one of [1] to

[16] , wherein:

[0101] The length of the recessed portion in the second direction is longer than the length of the semiconductor laser element in the second direction.

[0102] According to the above structure, the soldering member melted during reflow can overflow into the space in the recessed portion that does not overlap with the semiconductor laser element (table portion) in the second direction. In addition, when the optical element is a lens, the position of the semiconductor laser element in the second direction relative to the support member can be adjusted according to the focal length of the lens.

[18]

[0104] A semiconductor laser device according to any one of

[15] to

[17] , wherein:

[0105] The supporting substrate is further provided with a molding resin formed so as to cover the optical element, the base member, and the semiconductor laser element.

[0106] According to the above structure, the positional relationship of each component (optical element, base member and semiconductor laser element) arranged on the support substrate can be fixed by the mold resin, so that the positional relationship of each component can be prevented from being shifted. In addition, each component can be appropriately protected by the mold resin.

[0107] Effects of the Invention

[0108] According to one aspect of the present disclosure, it is possible to provide a semiconductor laser device capable of preventing short circuits between channels configured to be driven independently of each other and performing positional alignment of a plurality of light-emitting points with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Figure 1 It is a perspective view showing the semiconductor laser device according to the first embodiment.

[0110] Figure 2 Viewed from the side with the countertop Figure 1 A three-dimensional view of a semiconductor laser element of a semiconductor laser device.

[0111] Figure 3 It is along Figure 2 Cross-sectional view along line III-III.

[0112] Figure 4 Yes means Figure 1 A three-dimensional view of an auxiliary mount before a semiconductor laser element is mounted in a semiconductor laser device.

[0113] Figure 5 yes Figure 4 Magnified view of area A.

[0114] Figure 6 (A) is along Figure 5 Cross-sectional view along line VIa-VIa. Figure 6 (B) is along Figure 5 Cross-sectional view along line VIb-VIb.

[0115] Figure 7 It is a diagram showing the process of mounting the semiconductor laser element on the submount.

[0116] Figure 8 It is a top view showing a semiconductor laser element mounted on a submount.

[0117] Fig. 9 It is a side view of a portion including two table sections adjacent to each other.

[0118] Fig.10 It is a side view showing a modified example of the recessed portion.

[0119] Fig.11 It is a partial side view showing another modified example of the recessed portion.

[0120] Fig.12 It is a perspective view showing a semiconductor laser device according to a second embodiment.

[0121] Fig.13 Yes means Fig.12 Side view of a semiconductor laser device.

[0122] Fig.14 It is a perspective view showing a semiconductor laser device according to a third embodiment.

[0123] Fig.15 Yes means Fig.14 Side view of a semiconductor laser device. DETAILED DESCRIPTION

[0124] Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and repeated descriptions are omitted.

[0125] First embodiment

[0126] Reference Figures 1 to 9, a semiconductor laser device 1A according to a first embodiment is described. Figure 1 As shown in FIG. 1 , the semiconductor laser device 1A includes a semiconductor laser element 10 and an auxiliary mount 20 (support member). The semiconductor laser element 10 is mounted on the auxiliary mount 20 by a junction-down method. That is, the semiconductor laser element 10 is provided with an active layer 13 (see FIG. 1 ). Figure 3 ) is mounted on the auxiliary seat 20 in a manner such that a surface (lower surface 11b) on one side thereof faces the auxiliary seat 20.

[0127] In the present embodiment, the side on which the semiconductor laser element 10 is mounted relative to the auxiliary seat 20 is set as the upper side, and the side on which the laser L is emitted from the semiconductor laser element 10 to the outside is set as the front side. In addition, based on the above definition, the up and down direction is represented as the Z-axis direction (first direction), the front and rear direction is represented as the Y-axis direction (second direction), and the left and right direction is represented as the X-axis direction (third direction). The Z-axis direction is consistent with the relative direction of the semiconductor laser element 10 and the auxiliary seat 20. The Y-axis direction is a direction orthogonal to the Z-axis direction, and is consistent with the direction in which each of the multiple mesa portions 12 possessed by the semiconductor laser element 10 extends (that is, the laser emission direction). The X-axis direction is a direction orthogonal to both the Z-axis direction and the Y-axis direction, and is consistent with the arrangement direction of the multiple mesa portions 12.

[0128] The semiconductor laser element 10 is an end-emission type semiconductor laser element. The semiconductor laser element 10 has a substrate 11 and a plurality of (8 in this embodiment) mesa portions 12. The semiconductor laser element 10 may be a single-channel type having only a single channel, or a multi-channel type having a plurality of channels. Here, "channel" refers to a unit that emits light simultaneously. In other words, a channel is a unit that can be driven independently. One channel is composed of one or more mesa portions 12. For example, when two or more mesa portions 12 are electrically connected, one channel is composed of the two or more mesa portions 12. In this embodiment, as an example, each of the plurality of mesa portions 12 is electrically separated from each other, so the mesa portion 12 and the channel have a "1:1" relationship. That is, in this embodiment, the semiconductor laser element 10 is configured as a multi-channel (8-channel) type semiconductor laser element, and the number of mesa portions 12 (8) is consistent with the number of channels.

[0129] The substrate 11 is, for example, a semiconductor substrate such as a compound semiconductor substrate. The substrate 11 is formed in a rectangular plate shape (rectangular parallelepiped shape). Figure 1 and Figure 2 As shown, the substrate 11 has an upper surface 11a (first surface) and a lower surface 11b (second surface) located on opposite sides of each other in the Z-axis direction, a front surface 11c and a rear surface 11d located on opposite sides of each other in the Y-axis direction, and side surfaces 11e, 11f (fifth surface) located on opposite sides of each other in the X-axis direction.

[0130] An electrode 32 (second electrode) serving as a cathode electrode is provided on the upper surface 11a of the substrate 11. As an example, the electrode 32 is configured as a single electrode shared by a plurality of mesa portions 12. That is, the electrode 32 is provided on substantially the entire surface of the upper surface 11a in a manner overlapping with the plurality of mesa portions 12 in the Z-axis direction. The electrode 32 can be formed of a metal material such as AuGe, Ni, Au, etc. A wire for electrical connection to a power supply circuit (not shown) can be connected to the upper surface of the electrode 32 by wire bonding or the like.

[0131] The plurality of mesa portions 12 have light emitting end faces 12a that independently emit laser light L. Figure 2 As shown, a plurality of (eight in this embodiment) mesa portions 12 are arranged at approximately equal intervals along the X-axis direction. The light emitting end surface 12a of each mesa portion 12 intersects the Y-axis direction and emits the laser light L along the Y-axis direction. In addition, the light emitting end surface 12a is provided on both sides (front side and rear side) of each mesa portion 12 in the Y-axis direction, but in this embodiment, the light emitting end surface 12a on the front side functions as a light emitting end surface for emitting the laser light L to the outside. Therefore, in order not to emit the laser light L to the rear, a reflective film or the like may be provided on the light emitting end surface 12a on the rear side. On the other hand, in order to improve the efficiency of extracting light to the outside, a low-reflective film may be provided on the light emitting end surface 12a on the front side.

[0132] like Figure 2 As shown, each mesa portion 12 is formed so as to protrude in the Z-axis direction relative to a reference surface R1 (first reference surface) formed on the lower surface 11b of the substrate 11. In addition, each mesa portion 12 is formed so as to extend in the Y-axis direction. The reference surface R1 is a surface directly supported by the auxiliary seat 20 by surface contact with the reference surface R2 (second reference surface) of the auxiliary seat 20. As an example, the insulating layer 19 is continuously formed with a predetermined thickness on the entire lower surface 11b (including the surface of the mesa portion 12). In this case, the surface 19a of the insulating layer 19 on the opposite side to the side opposite to the substrate 11 functions as the reference surface R1.

[0133] Each table portion 12 has a top surface 12b and a pair of side surfaces 12c. The top surface 12b is aligned with the recess 21 of the auxiliary seat 20 (see Figure 4) is a surface opposite to the mesa portion 12. In other words, the top surface 12b is a surface on the opposite side to the side where the substrate 11 is located relative to the mesa portion 12. As an example, the top surface 12b is formed by a portion of the surface 19a of the insulating layer 19 that covers the surface 18a of the contact layer 18 described later. A pair of side surfaces 12c are surfaces located on opposite sides to each other in the X-axis direction. The side surfaces 12c are surfaces connecting the top surface 12b and the reference plane R1. A pair of side surfaces 12c are inclined relative to the top surface 12b and the reference plane R1 in such a manner that the interval between the pair of side surfaces 12c in the X-axis direction widens as the distance between them increases from the top surface 12b to the reference plane R1. That is, when viewed from the Y-axis direction, each mesa portion 12 is formed in a trapezoidal shape.

[0134] An electrode 35 (first electrode) which is an anode electrode electrically connected to each mesa portion 12 is provided on the top surface 12b of each mesa portion 12. That is, the electrode 35 is provided on each mesa portion 12. The electrode 35 can be formed of a metal material such as Ti, Pt, Au, etc. Figure 2 As shown, as an example, the electrode 35 is provided so as to cover most of the top surface 12 b of the mesa portion 12 (except for both side edges of the top surface 12 b in the Y-axis direction) and extend in the Y-axis direction.

[0135] like Figure 3 As shown, the mesa portion 12 has a stacked structure formed on the lower surface 11b of the substrate 11. As an example, the mesa portion 12 includes four first stacked structures L1, three second stacked structures L2, and a contact layer 18. More specifically, the first stacked structure L1 at the bottom (the side closest to the substrate 11) is stacked on the lower surface 11b of the substrate 11. Thereon, three first stacked structures L1 and three second stacked structures L2 are stacked in a manner to form a repeated structure in which one second stacked structure L2 is sandwiched by two first stacked structures L1. The contact layer 18 is stacked on the first stacked structure L1 at the top (the side farthest from the substrate 11).

[0136] The first stacked structure L1 includes an active layer 13, a first semiconductor side layer 14, and a second semiconductor layer 15. The layers constituting the first stacked structure L1 are stacked in the order of the first semiconductor layer 14, the active layer 13, and the second semiconductor layer 15 from the lower surface 11b side. The active layer 13 is, for example, a layer of a quantum well structure in which quantum well layers and barrier layers are alternately stacked in the Z-axis direction, and is a layer that generates laser light L. The active layer 13 has, for example, a structure in which InGaAs layers and InAlAs layers are alternately stacked in the stacking direction (Z-axis direction). The first semiconductor layer 14 can be formed, for example, of an n-type AlGaAs layer. The second semiconductor layer 15 can be formed, for example, of a p-type AlGaAs layer.

[0137] The second stacked structure L2 is a so-called tunnel junction, and includes a first tunnel junction layer 16 and a second tunnel junction layer 17. The first tunnel junction layer 16 is located closer to the lower surface 11b than the second tunnel junction layer 17. The first tunnel junction layer 16 can be formed, for example, of a GaAs layer doped with a high concentration of a p-type dopant. The second tunnel junction layer 17 can be formed, for example, of a GaAs layer doped with a high concentration of an n-type dopant.

[0138] The contact layer 18 may be formed of, for example, a GaAs layer doped with a high concentration of a p-type dopant. The contact layer 18 is a layer in contact with the electrode 35. The insulating layer 19 covering the surface 18a of the contact layer 18 opposite to the substrate 11 is provided with an opening 19b for exposing at least a portion of the surface 18a. Figure 2 and Figure 3 As shown in FIG. 1 , the opening 19b is provided at the center of the top surface 12b in the X-axis direction at the portion where the electrode 35 overlaps the contact layer 18. When viewed from the Z-axis direction, the opening 19b is formed into a rectangular shape extending in the Y-axis direction. Figure 2 The recessed portion of the middle electrode 35 corresponds to the portion where the opening 19b is formed. In the opening 19b, the surface of the electrode 35 is recessed by the electrode 35 entering the contact layer 18 side. The area overlapping with the opening 19b in the Z-axis direction of the surface 18a of the contact layer 18 (that is, the area exposed to the outside) functions as a contact area CA in contact with the electrode 35. In the present embodiment, the insulating layer 19 covers the two side edges of the surface 18a of the contact layer 18 in the X-axis direction, so the length d1 of the contact area CA in the X-axis direction is shorter than the length of the top surface 12b in the X-axis direction.

[0139] The auxiliary mount 20 is, for example, a silicon substrate formed of silicon. A circuit for driving the semiconductor laser element 10 may also be built inside the auxiliary mount 20. Figure 4 As shown, the auxiliary seat 20 is formed in a rectangular plate shape (rectangular parallelepiped shape). The auxiliary seat 20 has an upper surface 20a (third surface) and a lower surface 20b (sixth surface) located on opposite sides to each other in the Z-axis direction, a front surface 20c (fourth surface) and a rear surface 20d located on opposite sides to each other in the Y-axis direction, and side surfaces 20e and 20f located on opposite sides to each other in the X-axis direction. The upper surface 20a is a surface opposite to the reference surface R1 of the semiconductor laser element 10, and forms a reference surface R2 that is in surface contact with the reference surface R1. In the present embodiment, the reference surface R1 of the semiconductor laser element 10 is formed by the surface 19a of the insulating layer 19 provided on the lower surface 11b of the substrate 11, while the reference surface R2 of the auxiliary seat 20 is formed by the surface (upper surface 20a) of the auxiliary seat 20 itself.

[0140] The auxiliary seat 20 has a recess 21 formed on the upper surface 20a. The recess 21 is a portion that is formed to be more recessed toward the lower surface 20b side than other portions of the upper surface 20a in order to arrange (accommodate) a plurality of mesa portions 12 provided on the semiconductor laser element 10. The recess 21 can be formed, for example, by wet etching. As an example, the recess 21 is composed of a plurality of (eight in this embodiment) recesses 22 that individually accommodate each of the plurality of mesa portions 12. That is, in this embodiment, a plurality of recesses 22 arranged along the X-axis direction in a manner corresponding to each of the plurality of mesa portions 12 are provided on the upper surface 20a. The length of each recess 22 in the Y-axis direction is longer than the length of the substrate 11 in the Y-axis direction. A partition wall portion 23 is provided between adjacent recesses 22. The partition wall portion 23 extends in the Y-axis direction and has a predetermined length (i.e., a width greater than a certain value) in the X-axis direction, and has a reference surface R2. That is, adjacent recessed portions 22 are arranged at intervals greater than a certain distance in the X-axis direction, and portions corresponding to the intervals (ie, portions where recessed portions 22 are not formed) function as partition walls 23 .

[0141] like Figure 4 , Figure 5 as well as Figure 6 As shown, the recess 22 is formed into a groove extending in the Y-axis direction. The recess 22 extends to the front surface 20c and opens at the front surface 20c. The recess 22 has a bottom surface 22a intersecting the Z-axis direction, a pair of side surfaces 22b (first side surfaces) intersecting the X-axis direction, and a side surface 22c (second side surfaces) intersecting the Y-axis direction. In addition, Figure 4 , Figure 5 as well as Figure 6 The state before the semiconductor laser element 10 is mounted on the submount 20 is shown.

[0142] The pair of side surfaces 22b are surfaces that are opposite to the side surfaces 12c of the mesa portion 12 in the X-axis direction when the semiconductor laser element 10 is mounted on the auxiliary mount 20. The side surfaces 22b are inclined relative to the bottom surface 22a in such a manner that the opening width of the recess 22 in the upper surface 20a along the X-axis direction is greater than the width of the bottom surface 22a of the recess 22 along the X-axis direction. Figure 6 As shown in (A), the inclination angle θ1 of the side surface 22b relative to the bottom surface 22a is an acute angle. On the other hand, the angle θ2 formed by the upper surface 20a (reference plane R2) and the side surface 22b is an obtuse angle. As an example, the recess 22 is formed by wet etching, thereby forming the side surface 22b into a planar shape. In this case, the inclination angle θ1 and the angle θ2 have a relationship of "θ1+θ2=180°".

[0143] The side surface 22c is a surface formed at the rear of the recessed portion 22. The side surface 22c is inclined relative to the bottom surface 22a in such a manner that the opening width of the recessed portion 22 along the Y-axis direction in the upper surface 20a is greater than the width of the bottom surface 22a of the recessed portion 22 along the Y-axis direction. Figure 6 As shown in (B), the inclination angle θ3 of the side surface 22c with respect to the bottom surface 22a is an acute angle. As an example, by forming the recessed portion 22 by wet etching, the inclination angle θ3 is substantially consistent with the inclination angle θ1.

[0144] In the recessed portion 21, a wiring portion W is provided at a position corresponding to each of the plurality of mesa portions 12. As an example, the wiring portion W includes a plurality of wirings 31 arranged at each position corresponding to each of the plurality of mesa portions 12. The wirings 31 can be formed of a metal material such as Au. In the present embodiment, since an independent recessed portion 22 is formed in each mesa portion 12, Figure 5 As shown in FIG. 2 , a separate wiring 31 is provided in each recess 22. In each recess 22, the wiring 31 extends in the Y-axis direction along the bottom surface 22a. Figure 4 and Figure 5 As shown, the wiring 31 extends from the inside of the recess 22 to the upper surface 20a outside the recess 22. As an example, each wiring 31 extends to an electrode pad 34 independently provided on the upper surface 20a. That is, the plurality of wirings 31 are electrically separated from each other. Thus, current can flow independently to each of the plurality of mesa portions 12 (that is, each mesa portion 12 can be driven independently). Figure 5 and Figure 6 As shown in (B), the wiring 31 is along the bottom surface 22a and the side surface 22c. That is, the side surface 22c plays a role in guiding the wiring 31 from the inside of the recess 22 to the outside of the recess 22. In addition, a wire for electrically connecting to a power supply circuit (not shown) can be connected to each electrode pad 34 by wire bonding or the like.

[0145] like Figure 5 as well as Figure 6 As shown in (A), in each recess 22, a soldering member 33 is provided on the wiring 31 by vapor deposition or the like. The soldering member 33 can be formed of a material suitable for reflow soldering, such as Sn, Ag, Cu, or the like.

[0146] Reference Figure 7 , the mounting process of the semiconductor laser element 10 relative to the auxiliary mount 20 is described. First, Figure 7 As shown in S1 of FIG. 1 , a welding member 33 is arranged on the wiring 31 in each recess 22. Next, as shown in FIG. Figure 7As shown in S2 of FIG. 1 , the positions of the mesas 12 of the semiconductor laser element 10 are aligned with the positions of the recesses 22, and the semiconductor laser element 10 is placed on the auxiliary mount 20 in such a manner that the reference plane R1 and the reference plane R2 are opposite to each other. That is, the electrode 35 provided on the top surface 12b of each mesas 12 is brought into contact with the upper surface of the soldering member 33 arranged in each recess 22. Next, by heating in a reflow furnace, Figure 7 In the state shown in S2 of the semiconductor laser element 10 and the auxiliary mount 20, the welding member 33 is melted, and the semiconductor laser element 10 is adsorbed on the auxiliary mount 20. Specifically, the thickness of the welding member 33 in the Z-axis direction is reduced by melting the welding member 33, so that the semiconductor laser element 10 moves toward the auxiliary mount 20 until the reference surface R1 of the semiconductor laser element 10 contacts the reference surface R2 of the auxiliary mount 20. As a result, Figure 7 As shown in S3, each of the plurality of mesas 12 is accommodated in the recess 22, and the reference plane R1 is in surface contact with the reference plane R2. In addition, the electrodes 35 corresponding to each of the plurality of mesas 12 are electrically connected to the corresponding wiring 31 via the welding member 33.

[0147] like Figure 8 As shown, the upper surface 20a of the auxiliary seat 20 is provided with a Figure 7 The alignment mark M is used to align the semiconductor laser element 10 with respect to the auxiliary mount 20 in the mounting process shown. As an example, the alignment mark M has a cross shape when viewed from above. The alignment mark M is arranged on both sides of the semiconductor laser element 10 in the mounted state in the X-axis direction. Figure 8As shown, by making the inner end of each alignment mark M in the X-axis direction along the side surfaces 11e and 11f, the position of the semiconductor laser element 10 with respect to the auxiliary mount 20 in the X-axis direction can be aligned. In addition, as an example, marks (recesses 32a) corresponding to the alignment marks M are provided at both end portions in the X-axis direction of the electrode 32. By aligning the portions M1 extending inwardly in the X-axis direction of the alignment mark M and the recesses 32a in the Y-axis direction, the position of the semiconductor laser element 10 with respect to the auxiliary mount 20 in the Y-axis direction can be aligned. In addition, in the present embodiment, by such alignment, the semiconductor laser element 10 is arranged with respect to the auxiliary mount 20 in such a manner that the front surface 11c of the semiconductor laser element 10 and the front surface 20c of the auxiliary mount 20 are substantially flush, and therefore, by aligning the front surface 11c with the front surface 20c, the position of the semiconductor laser element 10 with respect to the auxiliary mount 20 in the Y-axis direction can also be determined. However, for example, when the semiconductor laser element 10 is arranged so that the front surface 11c of the substrate 11 is located forward or backward relative to the front surface 20c of the auxiliary mount 20, the position of the semiconductor laser element 10 in the Y-axis direction can be appropriately determined by using the above-mentioned portion M1 and the recess 32a as marks.

[0148] Reference Fig. 9 , the positional relationship between the table portions 12 in the embodiment will be described. Fig. 9 This is a side view of a portion including two table portions 12 adjacent to each other in the X-axis direction, viewed from the Y-axis direction (front). Here, the table portion 12 on the left side of the two table portions 12 viewed from the front is set as the first table portion 12A, and the table portion 12 on the right side is set as the second table portion 12B.

[0149] The first wiring 31A of the wiring 31 arranged in the recess 22 accommodating the first stage portion 12A is electrically separated (insulated) from the second wiring 31 of the wiring 31 arranged in the recess 22 accommodating the second stage portion 12B. In other words, the plurality of wirings 31 include the first wiring 31A and the second wiring 31B arranged adjacent to each other in the X-axis direction and electrically separated from each other. In addition, by arranging in a manner that the welding member 33 electrically connected to the first wiring 31A and the welding member 33 electrically connected to the second wiring 31B do not contact each other, the first stage portion 12A electrically connected to the first wiring 31A and the second stage portion 12B electrically connected to the second wiring 31B are electrically separated. In addition, in the present embodiment, as described above, the plurality of wirings 31 are electrically separated from each other. Therefore, any two wirings 31 arranged adjacent to each other in the X-axis direction among the plurality of wirings 31 are equivalent to the first wiring 31A and the second wiring 31B.

[0150] Here, the boundary between the side surface 12c of the terrace portion 12 and the reference plane R1 is represented as a base end P, the boundary between the side surface 12c of the first terrace portion 12A on the side where the second terrace portion 12B is located relative to the first terrace portion 12A and the reference plane R1, that is, the base end P is represented as a first base end P1, and the boundary between the side surface 12c of the second terrace portion 12B on the side where the first terrace portion 12A is located relative to the second terrace portion 12B and the reference plane R1, that is, the base end P is represented as a second base end P2. At this time, the distance d2 from the first base end P1 to the second base end P2 in the X-axis direction is longer than the length d1 of the contact area CA of the terrace portion 12 in the X-axis direction.

[0151] In addition, when viewed from the Y-axis direction, the distance d4 in the X-axis direction between the side surface 22b of the recessed portion 22 and the side surface 12c of the table portion 12 opposite to the side surface 22b becomes shorter along the Z-axis direction from the top surface 12b toward the base end P which is the boundary between the side surface 12c of the table portion 12 and the reference plane R1.

[0152] (Effect)

[0153] Next, the effects of the semiconductor laser device 1A described above will be described.

[0154] (First effect)

[0155] In the semiconductor laser device 1A, the reference surface R1 of the semiconductor laser element 10 (the surface 19a of the insulating layer 19 in this embodiment) is in surface contact with the reference surface R2 of the auxiliary mount 20. As a result, the positions of a plurality of light-emitting points (for example, the center of the light-emitting end surface 12a in the Z-axis direction) relative to the reference surface R2 of the auxiliary mount 20 can be aligned with high precision. In addition, the semiconductor laser device 1A has a first stage portion 12A and a second stage portion 12B that are electrically separated from each other (that is, configured to be driven independently of each other) and arranged adjacent to each other. Here, the amount of the required welding member 33 (for example, the width of the welding member 33 in the X-axis direction) may change depending on the width of the contact area CA (the length d1 in the X-axis direction), but in the semiconductor laser device 1A, the interval between the first stage portion 12A and the second stage portion 12B (that is, the distance d2 from the first base end portion P1 to the second base end portion P2 in the X-axis direction) is longer than the width d1 of the contact area CA. Thus, the interval between the first stage portion 12A and the second stage portion 12B can be sufficiently ensured for the amount of soldering member 33 required according to the length d1 of the contact area CA. As a result, when the semiconductor laser element 10 is mounted on the submount 20 by reflow soldering, the soldering member 33 corresponding to the first stage portion 12A and the soldering member 33 corresponding to the second stage portion 12B can be appropriately prevented from melting and contacting each other. Therefore, according to the semiconductor laser device 1A, short circuits between channels configured to be driven independently of each other can be prevented, and the positions of a plurality of light-emitting points can be aligned with high precision.

[0156] Furthermore, the semiconductor laser device 1A has the following structure in association with the first effect. Fig. 9 As shown, the recess 21 includes a recess 22 for accommodating (arranging) the first stage portion 12A, namely, a first recess 22A, and a recess 22 for accommodating the second stage portion 12B, namely, a second recess 22B. In addition, the length d3 of the partition wall portion 23 (i.e., the portion extending in the Y-axis direction so as to separate the first recess 22A from the second recess 22B) formed between the first recess 22A and the second recess 22B in the X-axis direction of the reference plane R2 is longer than the length d1 of the contact area CA in the X-axis direction. Fig. 9As shown, in this embodiment, the boundary B between the reference plane R2 and the side surface 22b of the recessed portion 22 is separated from the base end portion P in the X-axis direction. Therefore, the relationship of "d2>d3>d1" holds. In addition, the length d3 is the length of the boundary B between the reference plane R2 and the first recessed portion 22A (the boundary B on the second recessed portion 22B side) and the boundary B between the reference plane R2 and the second recessed portion 22B (the boundary B on the first recessed portion 22A side) in the X-axis direction. According to the above structure, the first stage portion 12A and the second stage portion 12B are accommodated in different recesses 22 (the first recess 22A and the second recess 22B), and the width (length d3) of the partition wall portion 23 between the first recess 22A and the second recess 22B is sufficiently ensured, thereby appropriately preventing the soldering member 33 corresponding to the first stage portion 12A (or the second stage portion 12B) that melts during reflow soldering from crossing the partition wall portion 23 and contacting (short-circuiting) the soldering member 33 corresponding to the second stage portion 12B (or the first stage portion 12A).

[0157] In addition, the recess 21 is composed of a plurality of recesses 22 that individually accommodate each of the plurality of mesa portions 12, and a partition wall portion 23 is provided between the adjacent recesses 22. According to the above structure, compared with a structure including a single recess 22 that accommodates two or more mesa portions 12, short circuits between adjacent mesa portions 12 can be appropriately prevented, and the reliability of independent driving of multiple channels can be improved. In addition, the contact area between the reference plane R1 and the reference plane R2 can be increased in the partition wall portion 23 provided between each recess 22, so that the stress of the semiconductor laser element 10 (mainly the substrate 11) can be reduced, and the occurrence of bending of the semiconductor laser element 10 can be suppressed. In particular, when the length of the substrate 11 in the X-axis direction is lengthened by arranging a plurality of mesa portions 12 in the X-axis direction as in the present embodiment, the substrate 11 is easily bent in the X-axis direction. The above structure is particularly effective in such a case.

[0158] In addition, in the present embodiment, by accommodating the first stage portion 12A and the second stage portion 12B in different recesses 22, it is possible to effectively prevent the welding member 33 corresponding to the first stage portion 12A and the welding member 33 corresponding to the second stage portion 12B from contacting each other. However, in order to obtain the above-mentioned first effect, it is not necessary to accommodate the first stage portion 12A and the second stage portion 12B in different recesses 22. For example, Fig.10 As shown, the recess 21 may also be composed of a single recess 22C that accommodates a plurality of (here, 8) mesa portions 12. In this case, a plurality of wirings 31 corresponding to each of the plurality of mesa portions 12 are provided on the bottom surface 22a of the single recess 22C. That is, the wiring portion W provided at the position corresponding to each of the plurality of mesa portions 12 includes a plurality of wirings 31 that are arranged at each position corresponding to each of the plurality of mesa portions 12 and are electrically separated from each other. Alternatively, as Fig.11 As shown, the recess 21 may also include a plurality of recesses 22 (however, the number is less than the total number of the terrace portions 12), and at least one recess 22D for accommodating two or more (here, three) terrace portions 12. According to the structure in which the above-mentioned "d2>d1" is established, even when the first terrace portion 12A and the second terrace portion 12B are accommodated in the same recess (that is, when the partition wall portion 23 is not provided between the first terrace portion 12A and the second terrace portion 12B), it is possible to effectively prevent the welding member 33 corresponding to the first terrace portion 12A and the welding member 33 corresponding to the second terrace portion 12B from short-circuiting.

[0159] In addition, if Fig.11 As in the example shown in FIG. 1 , the distance between adjacent table portions 12 (the distance corresponding to the distance d2 described above) may be uneven between all table portions 12. Fig.11 In the example of , the distance d21 between the rightmost mesa portion 12 accommodated in the recess 22D and the leftmost mesa portion 12 accommodated in the recess 22 adjacent to the right side of the recess 22D is longer than the distance d22 between the three mesa portions 12 accommodated in the recess 22D. For example, the distance between the mesa portions 12 that need to be electrically separated can be longer than the distance between the mesa portions 12 that do not need to be electrically separated. In addition, Fig.11 In the example of FIG. 2 , when the same channel is formed by three mesa portions 12 accommodated in the recess 22D, one wiring common to the three mesa portions 12 (a wiring formed with a wide width in the X-axis direction so as to overlap the three mesa portions 12) may be provided in the recess 22D. In this case, the three mesa portions 12 are electrically connected to each other via the one wiring.

[0160] In addition, in the present embodiment, the wiring section W includes a plurality of wirings 31 that are arranged at each position corresponding to each of the plurality of mesa portions 12 and are electrically separated from each other, and any two wirings 31 that are arranged adjacent to each other in the X-axis direction among the plurality of wirings 31 correspond to the first wiring 31A and the second wiring 31B described above. According to the above structure, between any two mesa portions 12 that are adjacent to each other, the interval between the mesa portions 12 (i.e., the distance d2) is longer than the width (length d1) of the contact area CA, so that short circuits between the channels can be prevented, and the plurality of mesa portions 12 (channels) can be driven independently.

[0161] That is, several of the plurality of wirings 31 may also be electrically connected to each other. For example, as described above, a common wiring 31 may also be formed in two or more mesa portions 12 belonging to the same channel. In this case, there is no problem even if the welding members 33 corresponding to the several wirings 31 are in contact with each other. Therefore, when the mesa portions 12 corresponding to the several wirings 31 are adjacent to each other in the X-axis direction, the interval (distance d2) between the mesa portions 12 may also be shorter than the width (length d1) of the contact area CA. That is, on the basis of obtaining the above-mentioned first effect, the above-mentioned relationship of "d2>d1" only needs to be established between the first mesa portion 12A and the second mesa portion 12B corresponding to the two wirings 31 (the first wiring 31A and the second wiring 31B) that are electrically separated from each other.

[0162] (Second effect)

[0163] In the semiconductor laser device 1A, the reference surface R1 of the semiconductor laser element 10 is in surface contact with the reference surface R2 of the auxiliary mount 20. Thus, the positions of a plurality of light-emitting points (for example, the center of the light-emitting end surface 12a in the Z-axis direction) can be aligned with respect to the reference surface R2 of the auxiliary mount 20 with high accuracy. In addition, in the semiconductor laser device 1A, the contact area between the reference surface R1 and the reference surface R2 can be increased in the partition wall portion 23 provided between the adjacent recesses 22, so that the stress of the semiconductor laser element 10 (mainly the substrate 11) can be reduced, and the occurrence of the bending of the semiconductor laser element 10 can be suppressed. More specifically, in the semiconductor laser device 1A, in addition to the reference surface R1 and the reference surface R2 being in contact in the regions on both sides of the semiconductor laser element in the X-axis direction (the region on the left side of the leftmost recess 22 and the region on the right side of the rightmost recess 22), the reference surface R1 and the reference surface R2 are also in contact in the partition wall portion 23, so that the stress of the semiconductor laser element 10 (mainly the substrate 11) can be effectively reduced. Here, from the viewpoint of suppressing the occurrence of bending of the semiconductor laser element 10, it is preferable to increase the contact surface between the reference plane R1 and the reference plane R2 as much as possible. For this reason, it is preferable to shorten the distance in the X-axis direction between the side surface 22b of the recess 22 and the boundary portion B of the reference plane R2 and the base end portion P of the mesa portion 12 opposite to the side surface 22b as much as possible. However, when the distance between the boundary portion B and the base end portion P is shortened in this way, the side surface 22b of the recess 22 and the side surface 12c of the mesa portion 12 become easy to contact, and the risk of damage to the mesa portion 12 increases. Therefore, in the semiconductor laser device 1A, the distance d4 in the X-axis direction between the side surface 22b of the recess 22 and the side surface 12c of the mesa portion 12 (see Fig. 9) is configured to be shorter from the top surface 12b toward the base end P along the Z-axis direction. According to the above structure, the risk of the side surface 22b of the recess 22 and the side surface 12c of the mesa portion 12 can be reduced, and the distance between the boundary portion B and the base end P can be shortened as much as possible. As a result, the damage of the semiconductor laser element 10 can be suppressed, and the contact surface between the reference surface R1 and the reference surface R2 can be increased as much as possible. Therefore, according to the semiconductor laser device 1A, the occurrence of the bending of the semiconductor laser element 10 can be appropriately suppressed, and the position alignment of a plurality of light-emitting points can be performed with high precision.

[0164] In addition, the semiconductor laser device 1A is associated with the second effect and has the following structure. That is, the plurality of recesses 22 are individually accommodated in each of the plurality of mesa portions 12. According to the above structure, the contact area between the reference plane R1 and the reference plane R2 can be increased in the plurality of partition walls 23 provided between the recesses 22, so that the stress of the semiconductor laser element 10 (mainly the substrate 11) can be further reduced, and the occurrence of the bending of the semiconductor laser element 10 can be effectively suppressed.

[0165] In addition, the wiring section W is arranged at each position corresponding to each of the plurality of mesa portions 12, and includes a plurality of wirings 31 electrically isolated from each other. According to the above structure, by separating any two adjacent mesa portions 12 by the partition wall portion 23 provided between the recesses 22, short circuits between the channels can be prevented, and the plurality of mesa portions 12 (channels) can be driven independently.

[0166] In addition, if Fig. 9 As shown, the inclination angle θ4 of the side surface 12c of the mesa portion 12 relative to the reference plane R1 is smaller than the inclination angle θ1 of the side surface 22b relative to the bottom surface 22a of the recessed portion 22 (see Figure 6 That is, in the present embodiment, the side surface 12c of the table portion 12 and the side surface 22b of the recessed portion 22 are both plane-shaped, and the inclination angle θ4 of the side surface 12c and the inclination angle θ1 of the side surface 22b have a relationship of "θ4<θ1", thereby realizing a structure in which the distance d4 becomes shorter as it moves from the top surface 12b to the base end P. According to the above structure, it is possible to easily and reliably realize a structure in which the distance d4 between the side surface 22b of the recessed portion 22 and the side surface 12c of the table portion 12 becomes shorter as it moves from the top surface 12b to the base end P.

[0167] In addition, if Figure 6As shown in (A), the angle θ2 formed by the reference plane R2 and the side surface 22b of the recessed portion 22 is an obtuse angle. According to the above structure, even when the semiconductor laser element 10 is mounted on the auxiliary mount 20, if the side surface 12c of the mesa portion 12 contacts the portion where the reference plane R2 and the side surface 22b intersect (i.e., the boundary portion B), the impact on the side surface 12c of the mesa portion 12 can be reduced compared to the case where the angle formed by the reference plane R2 and the side surface 22c is configured to be less than 90 degrees (i.e., the case where the boundary portion B is sharp). Therefore, according to the above structure, the risk of damage to the semiconductor laser element 10 during mounting can be reduced.

[0168] In addition, the boundary portion B between the reference surface R2 and the side surface 22b of the recessed portion 22 is separated from the base end portion P in the X-axis direction. According to the above structure, the semiconductor laser element 10 is mounted on the submount 20 in a manner that the boundary portion B does not contact the base end portion P, so that the risk of the side surface 12c of the mesa portion 12 contacting the boundary portion B during mounting can be reduced, and damage to the semiconductor laser element 10 can be appropriately prevented.

[0169] In addition, in order to obtain the second effect, it is not necessary to provide a plurality of recesses 22 for individually accommodating the table portion 12. In order to obtain the second effect, at least two recesses 22 and at least one partition wall 23 disposed therebetween are sufficient.

[0170] (Other effects)

[0171] A single electrode 32 is provided on the upper surface 11a of the substrate 11 of the semiconductor laser element 10 and is shared by a plurality of mesa portions 12. According to the above structure, by making the cathode electrode (electrode 32) disposed on the back surface (upper surface 11a) side of the substrate 11 shared by a plurality of mesa portions 12, the number of wires connected to the electrode 32 by wire bonding can be reduced, thereby suppressing damage to the semiconductor laser element 10 caused by wire bonding. More specifically, even if the electrode 32 is separated for each channel, at least the same number of wires as the number of channels is required, but according to the present embodiment, at least one wire is connected to the electrode 32.

[0172] like Figure 6 As shown in (A), the side surface 22b of the recess 22 is inclined relative to the bottom surface 22a in such a manner that the opening width of the recess 22 along the X-axis direction in the upper surface 20a of the auxiliary seat 20 is larger than the width of the bottom surface 22a of the recess 22 along the X-axis direction. That is, the inclination angle θ1 of the side surface 22b relative to the bottom surface 22a is an acute angle. According to the above structure, by configuring the side surface 22b of the recess 22 as an inclined surface that widens from the bottom surface 22a side toward the opening end side, it is possible to appropriately ensure a space in the recess 22 for the overflow of the melted solder member 33 during reflow.

[0173] like Figure 4 and Figure 5 As shown, the wiring 31 extends from the inside of the recess 22 to the upper surface 20a outside the recess 22. According to the above structure, the electrode (anode electrode) on the side of the mesa portion 12 of the semiconductor laser element 10 can be led to the surface (upper surface 20a) of the auxiliary mount 20 via the electrode 35 and the wiring 31, so that the installation of the structure for passing current through the semiconductor laser element 10 becomes easy. More specifically, the electrode pad 34 electrically connected to the electrode 35 as the anode electrode can be exposed on the same side as the electrode 32 as the cathode electrode (the side to which the upper surface 20a of the auxiliary mount 20 faces). As a result, the workability of wire bonding with respect to the electrode 32 and the electrode pad 34 can be improved.

[0174] like Figure 5 As shown in FIG. 1 , the wiring 31 (wiring portion W) extends from the inside of the recess 22 to the outside of the recess 22 along the Y-axis direction. Figure 6 As shown in (B), the recess 22 has a side 22c that intersects the Y-axis direction and along which the wiring 31 is located. In addition, the side 22c is inclined relative to the bottom surface 22a in such a manner that the opening width of the recess 22 in the upper surface 20a along the Y-axis direction is greater than the width of the bottom surface 22a of the recess 22 along the Y-axis direction. That is, the inclination angle θ3 of the side 22c relative to the bottom surface 22a is an acute angle. Assuming that the side 22c is not inclined as described above (for example, when the side 22c is a surface perpendicular to the bottom surface 22a of the recess 22), the wiring 31 is bent in a step-like shape at the boundary between the bottom surface 22a and the side 22c and the boundary between the side 22c and the upper surface 20a, so that the wiring 31 is easily broken. On the other hand, by configuring the side 22c as an inclined surface as described above and making the wiring 31 along the inclined side 22c, it is possible to avoid the wiring 31 from being bent in a step-like shape and suppress the occurrence of broken wires.

[0175] like Figure 3 As shown, each of the plurality of mesa portions 12 has one or more active layers 13 independently provided for each mesa portion 12. According to the above structure, the active layers 13 are spatially separated between the plurality of mesa portions 12, so that the occurrence of optical crosstalk between the mesa portions 12 can be reliably prevented. In addition, as in the present embodiment, when each mesa portion 12 is provided with a plurality of (four in the present embodiment) active layers 13, each mesa portion 12 can function as a stacked semiconductor laser element, and the laser output can be enhanced.

[0176] The submount 20 is formed of silicon. According to the above structure, the recessed portion 21 can be formed with high precision by, for example, an etching process.

[0177] The auxiliary seat 20 has a front surface 20c connected to the upper surface 20a and intersecting the Y-axis direction, and the recess 22 extends to the front surface 20c and opens at the front surface 20c. According to the above structure, the light emitting end surface 12a of each stage portion 12 accommodated in the recess 22 can be exposed to the outside from the portion of the recess 22 opened at the front surface 20c, so that the extraction efficiency of the laser light L emitted from the light emitting end surface 12a along the Y-axis direction can be improved.

[0178] The upper surface 20a of the submount 20 is provided with alignment marks M for aligning the semiconductor laser element 10 with respect to the submount 20. With the above configuration, when the semiconductor laser element 10 is mounted on the submount 20, the semiconductor laser element 10 can be easily and accurately aligned with respect to the submount 20.

[0179] The thickness of the substrate 11 in the Z-axis direction (the length from the upper surface 11a to the lower surface 11b) is smaller than the thickness of the auxiliary mount 20 in the Z-axis direction (the length from the upper surface 20a to the lower surface 20b). According to the above structure, by using the auxiliary mount 20 that is thicker than the semiconductor laser element 10, the deformation of the auxiliary mount 20 relative to the semiconductor laser element 10 (that is, the deformation of the reference surface R2) can be appropriately suppressed. As a result, the positions of the plurality of light-emitting points relative to the reference surface R2 of the auxiliary mount 20 can be aligned with higher accuracy.

[0180] The substrate 11 has side surfaces 11e and 11f intersecting the X-axis direction. In addition, the distance d5 in the X-axis direction from the end (boundary portion B) of the recessed portion 22 located closest to the side surfaces 11e and 11f in the X-axis direction to the side surfaces 11e and 11f (see Figure 7 ) is greater than the distance d6 in the Z-axis direction from the reference plane R1 to the top surface 12b of the mesa portion 12 (refer to Fig. 9 According to the above structure, the area of ​​the portion where the reference plane R1 contacts the reference plane R2 can be ensured to be greater than a certain value, which can improve the support stability of the semiconductor laser element 10 relative to the auxiliary seat 20.

[0181] In addition, as an example, the distance d6 (i.e., the height of the table portion 12) may also be set to be shorter than 1 / 2 of the depth of the recess 22 (i.e., the length in the Z-axis direction from the reference plane R2 to the bottom surface 22a). In this case, the space in the recess 22 that is not occupied by the table portion 12 can be appropriately ensured, so that, for example, the space for accumulating the soldering member 33 melted during reflow can be appropriately ensured. In addition, by making the height of the recess 22 deeper relative to the table portion 12, the risk of the table portion 12 contacting the recess 22 can be reduced, but if the height of the recess 22 is too deep relative to the table portion 12, the amount (height) of the soldering member 33 required to achieve reliable contact between the wiring 31 and the electrode 35 increases. From the above viewpoint, the distance d6 may also be set to be longer than 1 / 3 of the depth of the recess 22.

[0182] Second embodiment

[0183] Reference Figure 12-13 , a semiconductor laser device 1B according to a second embodiment will be described. The semiconductor laser device 1B is different from the semiconductor laser device 1A in that it further includes a support substrate 40 and a lens member 50 (optical element) in addition to the semiconductor laser device 1A according to the first embodiment. Fig.13 In the figure, only elements necessary for explaining the positional relationship among the semiconductor laser element 10, the submount 20, the support substrate 40, and the lens member 50 are shown, and elements not necessary for the above description (wiring 31, electrode pads 34, etc.) are omitted as appropriate.

[0184] The support substrate 40 is a member that supports the auxiliary seat 20 and the lens member 50. As an example, the support substrate 40 is formed into a rectangular plate whose length in the X-axis direction is the same as that of the auxiliary seat 20 and whose length in the Y-axis direction is longer than that of the auxiliary seat 20. As an example, the auxiliary seat 20 is arranged on the support substrate 40 in such a manner that a pair of side surfaces of the support substrate 40 intersecting the X-axis direction are substantially flush with the side surfaces 20f and 20e of the auxiliary seat 20, and in such a manner that the rearward surface of the support substrate 40 is substantially flush with the rear surface 20d of the auxiliary seat 20.

[0185] The lens member 50 is disposed at a position facing the semiconductor laser element 10 and the submount 20 in the Y-axis direction. The lens member 50 emits light from the light emitting end faces 12a (see Figure 1 ) is guided to the outside. In this embodiment, Fig.13As shown, the lens member 50 plays the role of focusing or collimating the laser light L emitted from the light emission end surface 12a of each mesa portion 12 with a certain diffusion angle. The lens member 50 includes: a main body 51, which has a lens function; a lower flange 52, which is provided on the lower side of the main body 51 (the side where the support substrate 40 is located); and an upper flange 53, which is provided on the upper side of the main body 51. The lower flange 52 and the upper flange 53 have the same rectangular plate shape. The lens member 50 has a lower surface 50a composed of the rectangular lower surface of the lower flange 52, and a light incident surface 50b formed by the rear surface of the main body 51, the lower flange 52 and the upper flange 53, and a light emission surface 50c formed on the opposite side of the main body 51 to the light incident surface 50b. The lower surface 50a and the light incident surface 50b are both flat surfaces. The light exit surface 50c is a lens surface having a curved shape convex outward (forward) when viewed from the X-axis direction. The light incident surface 50b is a surface on which the laser light L emitted from the light exit end surfaces 12a of each of the plurality of mesas 12 enters. The light incident surface 50b is in surface contact with the front surface 20c of the auxiliary mount 20.

[0186] The support substrate 40 has a support surface 40a that supports the auxiliary seat 20 and the lens member 50. The support surface 40a has a first support surface 40a1 that is in surface contact with the lower surface 20b of the auxiliary seat 20 and supports the auxiliary seat 20, and a second support surface 40a2 that is in surface contact with the lower surface 50a of the lens member 50 and supports the lens member 50. In addition, in the present embodiment, the first support surface 40a1 and the second support surface 40a2 are continuous in a flush manner, but the height position (position in the Z-axis direction) of the first support surface 40a1 and the height position of the second support surface 40a2 may be different from each other. That is, the support substrate 40 may also have a connection surface parallel to the XZ plane connecting the first support surface 40a1 and the second support surface 40a2.

[0187] According to the semiconductor laser device 1B, the auxiliary mount 20 and the lens member 50 on which the semiconductor laser element 10 is mounted are in surface contact with the first supporting surface 40a1 and the second supporting surface 40a2 of the supporting substrate 40 and are supported, so that the height positions of the semiconductor laser element 10 and the lens member 50 (i.e., the height positions of the respective members with respect to the supporting surface 40a (the first supporting surface 40a1 and the second supporting surface 40a2) of the supporting substrate 40) can be easily and accurately aligned. Fig.13 As shown in FIG. 1 , the thickness of the auxiliary seat 20 in the Z-axis direction is represented by T, and the height of the lower surface 50a from the central axis of the lens member 50 is represented by H. In this case, by using the distance d6 (refer to FIG. 1 ) in the Z-axis direction from the reference plane R1 to the top surface 12b of the mesa portion 12 Fig. 9) is adjusted in such a way that the relationship "H = T-d6 / 2" is established between the thickness T and the height H mentioned above, the height positions of the plurality of light-emitting points (the center of the light-emitting end surface 12a in the Z-axis direction) can be easily aligned with the center position of the lens component 50. In addition, the above-mentioned height position adjustment can also be performed by adjusting the height position of the second supporting surface 40a2 relative to the first supporting surface 40a1 of the supporting substrate 40. In short, the height positions of the semiconductor laser element 10 and the lens component 50 can be easily and appropriately aligned only by placing the auxiliary seat 20 and the lens component 50 on the supporting surface 40a of the supporting substrate 40.

[0188] In addition, in the semiconductor laser device 1B, by making the front surface 20c of the auxiliary mount 20 and the light incident surface 50b of the lens member 50 facing each other in the Y-axis direction in surface contact, the distance between the light emitting end surface 12a and the light incident surface 50b in the Y-axis direction can be adjusted with high accuracy. That is, when the semiconductor laser element 10 is mounted on the auxiliary mount 20, by adjusting the distance from the light emitting end surface 12a to the front surface 20c in the Y-axis direction, the distance from the light emitting end surface 12a to the light incident surface 50b can be adjusted. For example, when the light emitting end surface 12a of each mesa portion 12 is configured to be flush with the front surface 11c of the substrate 11, and the semiconductor laser element 10 is mounted on the auxiliary mount 20 in a manner that the front surface 11c of the substrate 11 is flush with the front surface 20c of the auxiliary mount 20, the light emitting end surface 12a is flush with the front surface 20c of the auxiliary mount 20. In this case, by bringing the front surface 20 c of the auxiliary mount 20 into surface contact with the light incident surface 50 b , the light emitting end surface 12 a of each mesa portion 12 can be brought into surface contact with the light incident surface 50 b .

[0189] In addition, as described in the description of the semiconductor laser device 1A, in the present embodiment, the length of the recess 21 in the Y-axis direction is longer than the length of the semiconductor laser element 10 in the Y-axis direction. According to the above structure, the solder member 33 melted during reflow can overflow into the space in the recess 21 that does not overlap with the semiconductor laser element 10 (table portion 12) in the Y-axis direction. In addition, the position of the semiconductor laser element 10 in the Y-axis direction relative to the auxiliary mount 20 can be adjusted according to the focal length of the lens member 50. That is, according to the above structure, within the range where the table portion 12 does not interfere with the auxiliary mount 20, the semiconductor laser element 10 can be arranged on the auxiliary mount 20 in such a manner that the front surface 11c of the semiconductor laser element 10 is located further rearward than the front surface 20c of the auxiliary mount 20. Thus, the distance between the light emitting end surface 12a in front of each table portion 12 and the light incident surface 50b can be appropriately adjusted.

[0190] Third embodiment

[0191] Reference Fig.14 as well as Fig.15 Next, a semiconductor laser device 1C according to a third embodiment will be described. The semiconductor laser device 1C is different from the semiconductor laser device 1B in that it further includes a molding resin 60 in addition to the semiconductor laser device 1B according to the second embodiment. Fig.15 In, with Fig.13 Similarly, only elements necessary for explaining the positional relationship among the semiconductor laser element 10, the auxiliary mount 20, the support substrate 40, the lens member 50, and the molding resin 60 are shown, and elements not necessary for the above explanation (wiring 31, electrode pads 34, etc.) are omitted as appropriate.

[0192] The molding resin 60 is formed on the support substrate 40 so as to cover the lens member 50, the auxiliary mount 20, and the semiconductor laser element 10. The semiconductor laser device 1C has a rectangular parallelepiped shape as a whole by including such a molding resin 60. The molding resin 60 can be formed by a resin molding technique such as transfer molding or compression molding. Examples of the resin material constituting the molding resin 60 include epoxy resins and silicone resins.

[0193] According to the semiconductor laser device 1C, the positional relationship of each component (lens component 50, auxiliary mount 20 and semiconductor laser element 10) arranged on the support substrate 40 can be fixed by the mold resin 60, so that the positional relationship of each component can be prevented from being shifted. In addition, each component can be appropriately protected by the mold resin 60.

[0194] Modifications

[0195] The embodiments and several modified examples of the present disclosure are described above, but the present disclosure is not necessarily limited to the structures shown in the above-mentioned embodiments and the modified examples. The materials and shapes of each structure are not limited to the specific materials and shapes described above, and various materials and shapes other than the above-mentioned can be used. In addition, a part of the structure included in the above-mentioned embodiments and modified examples can also be appropriately omitted or changed, and can also be arbitrarily combined.

[0196] For example, the recess 22 may be formed by a method other than wet etching. In this case, the inclination angle θ1 and the inclination angle θ3 may be different. In addition, the inclination angle θ1 of the side surface 22b of the recess 22 may not be constant over the entire area of ​​the side surface 22b in the Z-axis direction. For example, the side surface 22b may be formed in a manner such that the inclination angle relative to the bottom surface 22a changes stepwise from the upper surface 20a side to the bottom surface 22a side. In addition, the side surface 22b may not be planar, and may be, for example, curved. The above contents regarding the side surface 22b also apply to the side surface 22c.

[0197] In the second and third embodiments, the lens member 50 is described as an example of an optical element, but the optical element may be a member other than a lens such as an optical filter, a volume Bragg grating (VBG), etc. That is, the optical element may be any optical element as long as it has a lower surface (equivalent to the surface of the lower surface 50a) that can be in surface contact with and supported by the second supporting surface 40a2 of the supporting substrate 40, and the type of the optical element assembled in the semiconductor laser device is not particularly limited.

[0198] In addition, in the above-mentioned embodiment, each mesa portion 12 is completely accommodated in the recess 22, but a part of the mesa portion 12 may be arranged outside the recess 22. That is, at least a part of the mesa portion 12 may be arranged in the recess 22. For example, the light emission end surface 12a on the front side of the mesa portion 12 may protrude further forward than the front surface 20c of the auxiliary mount 20. In addition, for example, in the case where the reference plane R1 of the semiconductor laser element 10 is formed below than in the above-mentioned embodiment (for example, in the case where the reference plane R1 is formed by the surface of another member provided on the surface 19a of the insulating layer 19, etc.), a part of the mesa portion 12 (a part on the base end portion P side in the Z-axis direction) may be arranged outside the recess 22.

[0199] Description of Reference Numerals

[0200] 1A, 1B, 1C ... semiconductor laser device, 10 ... semiconductor laser element, 11 ... substrate, 11a ... upper surface (first surface), 11b ... lower surface (second surface), 11e, 11f ... side surface (fifth surface), 12 ... table portion, 12a ... light emitting end surface, 12A ... first table portion, 12B ... second table portion, 12b ... top surface, 12c ... side surface, 13 ... active layer, 18 ... contact layer, 20 ... auxiliary seat (support member), 20a ... upper surface (third surface), 20b ... lower surface (sixth surface), 20c ... front surface (fourth surface), 21, 22, 22C, 22D ... recessed portion, 22a ... bottom surface, 22b ... side surface (first side), 22c…side (second side), 22A…first recess, 22B…second recess, 23…partition wall portion, 31…wiring, 31A…first wiring, 31B…second wiring, 32…electrode (second electrode), 33…welding member, 35…electrode (first electrode), 40…support substrate, 40a1…first supporting surface, 40a2…second supporting surface, 50…lens member (optical element), 50b…light incident surface, 60…molding resin, CA…contact area, M…alignment mark, P1…first base end portion, P2…second base end portion, R1…reference plane (first reference plane), R2…reference plane (second reference plane), W…wiring portion.

Claims

1. A semiconductor laser device, wherein: have: A semiconductor laser element, comprising: a substrate having a first surface and a second surface located on opposite sides to each other in a first direction; and a plurality of mesa portions having light emitting end faces intersecting a second direction orthogonal to the first direction and formed in a manner protruding in the first direction relative to a first reference plane formed on the second surface and extending in the second direction; as well as A support member having: a third surface forming a second reference surface opposite to the first reference surface; and a recessed portion formed on the third surface and provided with the plurality of table portions, The mesa portion has: a top surface that faces the bottom surface of the recess; and a pair of side surfaces that are located on opposite sides of each other in a third direction that is orthogonal to the first direction and the second direction. A first electrode is provided on the top surface of the mesa portion and is electrically connected to a contact layer provided on the top surface side of the mesa portion. The recessed portion is provided with wiring portions at positions corresponding to the respective ones of the plurality of mesa portions. The first electrodes corresponding to the respective mesa portions are electrically connected to the wiring portion via a welding member, The wiring section includes a first wiring and a second wiring that are arranged adjacent to each other in the third direction and are electrically separated from each other, The first table portion as the table portion electrically connected to the first wiring and the second table portion as the table portion electrically connected to the second wiring are arranged so as not to contact each other, thereby electrically separating the first table portion as the table portion electrically connected to the first wiring and the second table portion as the table portion electrically connected to the second wiring, The first reference surface is in surface contact with the second reference surface, A distance in the third direction from a first base end portion which is a boundary between the side surface of the first table portion on the side where the second table portion is located relative to the first table portion and the first reference plane to a second base end portion which is a boundary between the side surface of the second table portion on the side where the first table portion is located relative to the second table portion and the first reference plane is longer than a length in the third direction of a contact region in the contact layer that is in contact with the first electrode.

2. The semiconductor laser device according to claim 1, wherein The recess has: a first recess having the first stage portion disposed therein; and a second recess having the second stage portion disposed therein. The length of the second reference surface of the partition wall portion formed between the first recess and the second recess and extending in the second direction to separate the first recess and the second recess is longer in the third direction than the length of the contact region.

3. The semiconductor laser device according to claim 1, wherein The recessed portion is composed of a plurality of recessed portions in which the plurality of terrace portions are individually arranged. A partition wall portion is provided between the adjacent recessed portions. The partition wall portion extends along the second direction, has a predetermined length in the third direction, and has the second reference surface.

4. The semiconductor laser device according to claim 1, wherein A single second electrode common to the plurality of mesa portions is provided on the first surface.

5. The semiconductor laser device according to claim 1, wherein The recessed portion has a first side surface opposite to the side surface of the table portion in the third direction, The first side surface is inclined relative to the bottom surface in such a manner that an opening width of the recessed portion of the third surface along the third direction is greater than a width of the bottom surface of the recessed portion along the third direction.

6. The semiconductor laser device according to claim 1, wherein The wiring portion extends from the inside of the recess to the third surface outside the recess.

7. The semiconductor laser device according to claim 6, wherein The wiring portion extends from the inside of the recess to the outside of the recess along the second direction, The recess has a second side surface intersecting the second direction and on which the wiring portion extends, The second side surface is inclined with respect to the bottom surface such that an opening width of the recessed portion of the third surface along the second direction is larger than a width of the bottom surface of the recessed portion along the second direction.

8. The semiconductor laser device according to claim 1, wherein Each of the plurality of mesa portions has one or more active layers independently provided for each of the mesa portions.

9. The semiconductor laser device according to claim 1, wherein The wiring section includes a plurality of wirings which are arranged at positions corresponding to the respective ones of the plurality of mesa sections and are electrically separated from each other. Any two wirings arranged adjacent to each other in the third direction among the plurality of wirings correspond to the first wiring and the second wiring.

10. The semiconductor laser device according to claim 1, wherein The support member is formed of silicon.

11. The semiconductor laser device according to claim 1, wherein The support member has a fourth surface connected to the third surface and intersecting the second direction, The recessed portion extends to the fourth surface and opens at the fourth surface.

12. The semiconductor laser device according to claim 1, wherein The third surface is provided with an alignment mark for aligning the semiconductor laser element with respect to the base member.

13. The semiconductor laser device according to claim 1, wherein A thickness of the substrate in the first direction is smaller than a thickness of the seating member in the first direction.

14. The semiconductor laser device according to claim 1, wherein The substrate has a fifth surface intersecting the third direction, A distance in the third direction from an end of the recessed portion located closest to the fifth surface in the third direction to the fifth surface is longer than a distance in the first direction from the first reference surface to the top surface of the mesa portion.

15. The semiconductor laser device according to claim 1, wherein Also available: an optical element disposed at a position opposed to the semiconductor laser element and the support member in the second direction and guiding light emitted from the light emitting end faces of each of the plurality of mesa portions to the outside; as well as a supporting substrate supporting the support member and the optical element, The support substrate has: a first support surface that is in surface contact with a sixth surface of the support member on the opposite side of the third surface and supports the support member; and a second supporting surface which is in surface contact with the optical element and supports the optical element.

16. The semiconductor laser device according to claim 15, wherein The optical element has a light incident surface into which the light emitted from the light emitting end surface of each of the plurality of mesa portions is incident. The support member has a fourth surface opposite to the light incident surface, The light incident surface is in surface contact with the fourth surface.

17. The semiconductor laser device according to claim 1 or 15, wherein: The length of the recessed portion in the second direction is longer than the length of the semiconductor laser element in the second direction.

18. The semiconductor laser device according to claim 15 or 16, wherein: The support substrate further includes a mold resin formed so as to cover the optical element, the base member, and the semiconductor laser element.

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