Semiconductor laser device

Abstract

This semiconductor laser device (1) comprises: a housing (2) that has a flat bottom surface (6a); semiconductor laser elements (10–15) that are arranged in the housing (2); fast axis collimator lenses (30–35) that respectively collimate laser beams that are respectively emitted from the semiconductor laser elements (10–15) in a fast axis direction; prisms (40–45) that respectively deflect the laser beams in the fast axis direction; and slow axis collimator lenses (60–65) that respectively collimate the laser beams in a slow axis direction. The prisms (40–45) are arranged between the fast axis collimator lenses (30–35) and the slow axis collimator lenses (60–65), and the laser beams that are respectively emitted from the slow axis collimator lenses (60–65) have different optical axis positions in the fast axis direction from one another.

Description

semiconductor laser device

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

[0002] Patent Document 1 describes a semiconductor laser device including a multistage base, a plurality of semiconductor laser elements, a plurality of fast-axis collimator lenses, a plurality of slow-axis collimator lenses, and a plurality of reflecting mirrors, a condenser lens, and an optical fiber, all of which are mounted on the multistage base. Each of the plurality of semiconductor laser elements, each of the plurality of fast-axis collimator lenses, each of the plurality of slow-axis collimator lenses, and each of the plurality of reflecting mirrors is disposed on each stage of the multistage base. Laser light emitted from each of the plurality of semiconductor laser elements is collimated by the fast-axis collimator lens and the slow-axis collimator lens, deflected by the reflecting mirror, and then incident on the condenser lens. The condenser lens focuses the incident laser light onto the incident end face of the optical fiber, thereby enabling spatial multiplexing of the plurality of laser light.

[0003] The semiconductor laser device described in Patent Document 1 attempts to realize a compact, high-output laser light source with the above-described configuration.

[0004] US Patent Application Publication No. 2009 / 0245315

[0005] In the semiconductor laser device described in Patent Document 1, due to misalignment of the fast-axis collimator lens in the fast-axis direction, the optical axis of the laser beam emitted from the fast-axis collimator lens is angularly misaligned with the optical axis of the downstream optical system. As a result, when multiple laser beams are spatially combined, the optical axes of the multiple laser beams are angularly misaligned with the optical axis of the downstream optical system, resulting in a decrease in the light utilization efficiency of the downstream optical system. While it is possible to correct such an angular misalignment of the optical axis using a reflecting mirror, this requires a large effective area of ​​the reflecting mirror, resulting in a large semiconductor laser device. Furthermore, when correcting the optical axis angle using a reflecting mirror, the amount of change in the optical axis angle is twice as large as the amount of change in the correction angle of the reflecting mirror, making fine adjustment of the optical axis angle difficult.

[0006] Therefore, an object of the present disclosure is to facilitate adjustment of the angle of the optical axis in a semiconductor laser device including a plurality of semiconductor laser elements.

[0007] In order to achieve the above object, a semiconductor laser device according to one aspect of the present disclosure includes: a housing having a flat bottom surface; a plurality of semiconductor laser elements disposed within the housing; a plurality of fast-axis collimator lenses that collimate, in a fast-axis direction, each of a plurality of laser beams emitted from the plurality of semiconductor laser elements; a plurality of prisms that deflect, in the fast-axis direction, each of the plurality of laser beams; and a plurality of slow-axis collimator lenses that collimate, in a slow-axis direction, each of the plurality of prisms,

[0008] According to the present disclosure, in a semiconductor laser device including a plurality of semiconductor laser elements, it is possible to facilitate adjustment of the angle of the optical axis.

[0009] 1 is a perspective view showing a configuration of a semiconductor laser device according to a first embodiment. FIG. 2 is a perspective view showing an optical path of laser light in the semiconductor laser device according to the first embodiment. FIG. 3 is a side view showing an optical path of laser light in the semiconductor laser device according to the first embodiment. FIG. 4 is a side view showing an optical path of laser light in the semiconductor laser device according to the first embodiment. FIG. 5 is a graph showing a relationship between an installation angle of a prism and a deflection angle of laser light deflected by the prism. FIG. 6 is a side view showing an optical path of laser light in a semiconductor laser device according to a first modification of the first embodiment. FIG. 7 is a side view showing an optical path of laser light in a semiconductor laser device according to a second modification of the first embodiment. FIG. 8 is a side view showing an optical path of laser light in a semiconductor laser device according to a third modification of the first embodiment. FIG. 9 is a side view showing a configuration of a prism installation surface in a semiconductor laser device according to a fourth modification of the first embodiment. FIG. 10 is a perspective view showing a configuration of a semiconductor laser device according to a second embodiment. FIG. 11 is a plan view showing a configuration of a semiconductor laser device according to the second embodiment. FIG. 12 is a diagram showing a state of a prism before a bonding material is hardened when the prism is fixed to an element installation surface using a bonding material. FIG. 13 is a diagram showing a state of a prism after the bonding material is hardened when the prism is fixed to an element installation surface using a bonding material. FIG. 1 is a plan view showing the configuration of a semiconductor laser device according to a modified example of embodiment 2. FIG. 2 is a perspective view showing the configuration of a semiconductor laser device according to embodiment 3. FIG. 3 is a side view showing the configuration of a semiconductor laser element etc. according to embodiment 3. FIG. 4 is a perspective view showing the configuration of a semiconductor laser device according to embodiment 4. FIG. 5 is a side view showing the configuration of a semiconductor laser device according to embodiment 5. FIG. 6 is a perspective view showing the configuration of a semiconductor laser device according to embodiment 6.

[0010] Semiconductor laser devices according to embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, component arrangements and connection forms, steps, and step orders shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0011] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. Furthermore, in each figure, substantially the same components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0012] Furthermore, in this specification, terms indicating the relationship between elements, such as "equal," terms indicating the shape of elements, such as "flat," "parallel," "vertical," "plate-shaped," and "curved," as well as numerical ranges, are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0013] In this specification, the terms "above" and "below" do not refer to vertically above and below in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in a stacked configuration. The terms "above" and "below" are used not only when two components are arranged with a gap between them and another component is present between them, but also when two components are arranged closely together and are in contact with each other.

[0014] First Embodiment A semiconductor laser device according to a first embodiment will be described.

[0015] [1-1. Configuration] The configuration of a semiconductor laser device according to a first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing the configuration of a semiconductor laser device 1 according to this embodiment. In FIG. 1, the lid of a housing 2 of the semiconductor laser device 1 and part of a side wall 3 are not shown in order to show the interior of the semiconductor laser device 1. FIGS. 2 and 3 are a perspective view and a side view, respectively, showing the optical paths of laser beams L0A to L0E and L1A to L1E in the semiconductor laser device 1 according to this embodiment. In FIGS. 2 and 3, part of the optical axis of each laser beam is indicated by a dashed-dotted arrow, and the outline of each laser beam is indicated by a broken line. Note that each figure shows an X-axis, a Y-axis, and a Z-axis, which are orthogonal to one another. The X-axis, the Y-axis, and the Z-axis are in a right-handed Cartesian coordinate system. Hereinafter, relative positions in the X-axis direction may be expressed as "upper" (or "upper") or "lower" (or "lower"). For example, a position on the positive side of a certain position in the X-axis direction may be referred to as an upper position, and a position on the negative side of the X-axis direction may be referred to as a lower position.

[0016] 1, the semiconductor laser device 1 includes a housing 2, a plurality of semiconductor laser elements 10 to 15, fast-axis collimator lenses 30 to 35, prisms 40 to 45, slow-axis collimator lenses 60 to 65, and a plurality of reflecting mirrors 70 to 75. In this embodiment, the semiconductor laser device 1 further includes submounts 20 to 25, a plurality of laser mounting surfaces 80 a to 85 a, a plurality of element mounting surfaces 80 to 85, a condenser lens 90, an optical fiber 4, and current introduction terminals 9 a and 9 b.

[0017] The semiconductor laser device 1 is a module that can spatially combine laser beams emitted from a plurality of semiconductor laser elements 10 to 15 by an optical system and emit the combined laser beams.

[0018] The housing 2 is a container having a flat bottom surface 6a. The bottom surface 6a is a flat region of the main surface of the bottom 6 that is located inside the housing 2. In other words, the bottom surface 6a is a surface that is in the same plane. In this embodiment, the bottom surface 6a is the entire main surface of the bottom 6. Note that the main surface of the bottom 6 that is located inside the housing 2 may have a non-flat region (i.e., a region other than the bottom surface 6a). The housing 2 has a bottom 6, a sidewall 3, and a lid (not shown). The housing 2 may be an airtight package that hermetically seals an internal space in which multiple semiconductor laser elements 10-15 and the like are disposed. In other words, the housing 2 may hermetically seal multiple semiconductor laser elements 10-15, multiple fast-axis collimator lenses 30-35, multiple prisms 40-45, and multiple slow-axis collimator lenses 60-65.

[0019] The bottom 6 is a plate-like member disposed at the bottom (the lower end, i.e., the end on the negative side in the X-axis direction in each drawing) of the housing 2. The bottom 6 has a flat bottom surface 6a. The bottom surface 6a is the main surface of the bottom 6 that is located inside the housing 2.

[0020] The sidewalls 3 are disposed perpendicular to the bottom 6 of the housing 2. The sidewalls 3 are disposed so as to surround the semiconductor laser elements 10 to 15. The sidewalls 3 are made of, for example, Cu, a Cu alloy, an Fe—Ni—Co alloy, or Al. The bottom 6 is made of, for example, Cu, a Cu alloy, Al, or a ceramic having high thermal conductivity (for example, AlN or BeO). The lid is a member that covers the upper part of the housing 2.

[0021] The current introduction terminals 9a and 9b are terminals for introducing current from the outside of the housing 2 to the inside of the housing 2. One end of each of the current introduction terminals 9a and 9b is disposed outside the housing 2, and the other end is disposed inside the housing 2. In this embodiment, the current introduction terminals 9a and 9b are disposed on the side wall 3 and penetrate the side wall 3. If the side wall 3 is formed of a conductive material, an insulating member is disposed between the current introduction terminals 9a and 9b and the side wall 3.

[0022] The plurality of element mounting surfaces 80 to 85 are surfaces on which the plurality of reflective mirrors 70 to 75 are respectively mounted. That is, the reflective mirror 70 is mounted on the element mounting surface 80, the reflective mirror 71 is mounted on the element mounting surface 81, the reflective mirror 72 is mounted on the element mounting surface 82, the reflective mirror 73 is mounted on the element mounting surface 83, the reflective mirror 74 is mounted on the element mounting surface 84, and the reflective mirror 75 is mounted on the element mounting surface 85. The plurality of element mounting surfaces 80 to 85 have different heights from the bottom surface 6a. Specifically, the height of the element mounting surface 81 from the bottom surface 6a is higher than that of the element mounting surface 80, the height of the element mounting surface 82 from the bottom surface 6a is higher than that of the element mounting surface 81, the height of the element mounting surface 83 from the bottom surface 6a is higher than that of the element mounting surface 82, the height of the element mounting surface 84 from the bottom surface 6a is higher than that of the element mounting surface 83, and the height of the element mounting surface 85 from the bottom surface 6a is higher than that of the element mounting surface 84. In this embodiment, the element mounting surfaces 80 to 85 are flat surfaces parallel to the bottom surface 6a, and the difference in height between two adjacent element mounting surfaces and the bottom surface 6a is 0.50 mm.

[0023] The laser mounting surfaces 80a to 85a are surfaces on which the plurality of semiconductor laser elements 10 to 15 are respectively mounted. That is, the semiconductor laser element 10 is mounted on the laser mounting surface 80a, the semiconductor laser element 11 is mounted on the laser mounting surface 81a, the semiconductor laser element 12 is mounted on the laser mounting surface 82a, the semiconductor laser element 13 is mounted on the laser mounting surface 83a, the semiconductor laser element 14 is mounted on the laser mounting surface 84a, and the semiconductor laser element 15 is mounted on the laser mounting surface 85a. The plurality of laser mounting surfaces 80a to 85a have different heights from the bottom surface 6a. Specifically, the laser mounting surface 81a is higher from the bottom surface 6a than the laser mounting surface 80a, the laser mounting surface 82a is higher from the bottom surface 6a than the laser mounting surface 81a, the laser mounting surface 83a is higher from the bottom surface 6a than the laser mounting surface 82a, the laser mounting surface 84a is higher from the bottom surface 6a than the laser mounting surface 83a, and the laser mounting surface 85a is higher from the bottom surface 6a than the laser mounting surface 84a. Furthermore, the laser mounting surfaces 80a to 85a are higher from the bottom surface 6a than the element mounting surfaces 80 to 85, respectively. In this embodiment, the laser mounting surfaces 80a to 85a are flat surfaces parallel to the bottom surface 6a. Furthermore, the difference in height from the bottom surface 6a between two adjacent laser mounting surfaces is 0.50 mm.

[0024] In this embodiment, the semiconductor laser device 1 includes a multi-step base 8 having a plurality of element mounting surfaces 80 to 85 and a plurality of laser mounting surfaces 80 a to 85 a. The multi-step base 8 has a plurality of staircase-like steps. A surface parallel to the bottom surface 6 a of each of the plurality of steps of the multi-step base 8 corresponds to each of the plurality of element mounting surfaces 80 to 85 or each of the plurality of laser mounting surfaces 80 a to 85 a.

[0025] The multi-step base 8 has a lower surface 8ba and is placed on the bottom surface 6a so that the lower surface 8ba is parallel to the bottom surface 6a. The multi-step base 8 has a plurality of stair-like steps. Each of the plurality of steps of the multi-step base 8 has a surface parallel to the lower surface 8ba, and the surfaces parallel to the lower surface 8ba correspond to each of the plurality of element mounting surfaces 80 to 85. Therefore, each of the plurality of element mounting surfaces 80 to 85 is parallel to the bottom surface 6a. Furthermore, each of the plurality of element mounting surfaces 80 to 85 is parallel to one another and is not on the same plane.

[0026] In this embodiment, the plurality of element mounting surfaces 80 to 85 and the plurality of laser mounting surfaces 80 a to 85 a are formed on one multi-stage base 8, but the configuration of each mounting surface is not limited to this. For example, the semiconductor laser device 1 may include a first multi-stage base having the plurality of laser mounting surfaces 80 a to 85 a and a second multi-stage base having the plurality of element mounting surfaces 80 to 85.

[0027] The semiconductor laser elements 10 to 15 are elements that convert input power and emit laser light, and are arranged inside the housing 2. The semiconductor laser elements 10 to 15 are arranged in the Y-axis direction. In this embodiment, the semiconductor laser elements 10 to 15 are mounted on the laser mounting surfaces 80 a to 85 a, respectively. Specifically, the semiconductor laser elements 10 to 15 are mounted on the laser mounting surfaces 80 a to 85 a via the submounts 20 to 25, respectively. The semiconductor laser elements 10 to 15 may be fixed with, for example, an inorganic adhesive.

[0028] Each of the plurality of semiconductor laser elements 10-15 is a laser element having a semiconductor laminate film and an optical waveguide formed on a semiconductor substrate. The semiconductor laser elements 10-15 each convert power input from the outside to the optical waveguide into stimulated emission light such as laser light and emit the light from an emission point (see emission points 10e and 11e shown in FIG. 3) which is one end of the optical waveguide. The semiconductor laser elements 10-15 each emit a plurality of laser beams L0A-L5A. In this embodiment, the plurality of laser beams L0A-L5A are emitted parallel to the Z-axis direction from the plurality of semiconductor laser elements 10-15.

[0029] The fast axes of the laser beams L0A to L5A are axes in the stacking direction of the semiconductor laminated films of the semiconductor laser elements 10 to 15, and the slow axes orthogonal to the fast axes are axes parallel to the stacking planes of the semiconductor laminated films. In this embodiment, the fast axis direction of each of the laser beams L0A to L5A immediately after being emitted from the semiconductor laser elements 10 to 15 is the height direction from the bottom surface 6 a (the X-axis direction in each drawing).

[0030] The wavelength of each laser beam varies depending on the semiconductor material constituting the semiconductor laminated film of each semiconductor laser element. For example, by using nitride-based semiconductor laser elements whose main components are nitrides of Al, Ga, and In, the semiconductor laser elements 10-15 can emit laser beams having peak wavelengths between 350 nm and 550 nm. Furthermore, by using semiconductor laser elements whose main components are semiconductors composed of Al, Ga, In, As, and P, the semiconductor laser elements 10-15 can emit laser beams having peak wavelengths between 600 nm and 1600 nm. The semiconductor laser elements 10-15 are not limited to semiconductor laser elements made of the above-mentioned semiconductor materials, and the wavelengths of the laser beams emitted by the semiconductor laser elements 10-15 are not limited to those mentioned above. In this embodiment, the peak wavelength of the laser beams emitted by the semiconductor laser elements 10-15 is 455 nm.

[0031] The multiple semiconductor laser elements 10 to 15 have a rectangular shape that is long in the waveguiding direction of the optical waveguide. In this embodiment, the length of each semiconductor laser element (the dimension in the Z-axis direction in FIG. 1) is 1.00 mm, and the width of each semiconductor laser element (the dimension in the Y-axis direction in FIG. 1) is 0.20 mm. The optical waveguide has a width of, for example, 5 μm or more and 300 μm or less, and a length of, for example, 0.50 mm or more and 5.00 mm or less. In this embodiment, the length of the optical waveguide of each semiconductor laser element (i.e., the length of each semiconductor laser element) is 1.00 mm. The multiple semiconductor laser elements 10 to 15 are transverse multimode lasers in which laser light is multimode in the slow axis.

[0032] Furthermore, in this embodiment, the multiple semiconductor laser elements 10 to 15 are laser elements in which Fabry-Perot mirrors are formed at both ends of the optical waveguide, but the configuration of the multiple semiconductor laser elements 10 to 15 is not limited to this. For example, the multiple semiconductor laser elements 10 to 15 may be so-called superluminescent diodes in which no mirror is formed on the light-emitting point side of the optical waveguide. Furthermore, the multiple semiconductor laser elements 10 to 15 may be elements for so-called external cavity type semiconductor lasers in which no mirror is formed on the light-emitting point side of the optical waveguide, but a cavity mirror is arranged as a separate component from the multiple semiconductor laser elements 10 to 15 on the side in the direction of emission of the emitted light, thereby performing laser oscillation.

[0033] In this embodiment, the divergence angle in the fast axis direction immediately after the laser light is emitted from each semiconductor laser element is 45 degrees (0.79 rad), and the divergence angle in the slow axis direction is 10 degrees (0.17 rad). Here, the divergence angle is the angle at which the light intensity is 1 / e with respect to the peak. ２ It is defined as the width (full width) of the angular range over which the intensity is

[0034] In this embodiment, current is supplied to the multiple semiconductor laser elements 10 to 15 from outside the housing 2 via current introduction terminals 9a and 9b. The multiple semiconductor laser elements 10 to 15 are connected in series using, for example, metal wires or the like. Furthermore, the current introduction terminal 9a and the current introduction terminal 9b are connected to the semiconductor laser elements 10 and 15, respectively, by metal wires or the like. Note that, when the distance is long, such as between the current introduction terminal 9a and the semiconductor laser element 10, a conductive wiring member may be disposed to relay the distance therebetween. In other words, the current introduction terminal 9a and the wiring member, and the wiring member and the semiconductor laser element 10 may each be connected by a metal wire or the like.

[0035] One electrode of the semiconductor laser element 10 is connected to an electrode on the submount 20 via a conductive bonding material such as Au or AuSn, and the electrode on the submount 20 is connected to the current introduction terminal 9a by a metal wire or the like. The other electrode of the semiconductor laser element 10 is connected to the semiconductor laser element 11 by a metal wire or the like. One electrode of the semiconductor laser element 11 is connected to an electrode on the submount 21, and the electrode on the submount 21 is connected to the other electrode of the semiconductor laser element 10 by a metal wire or the like. The semiconductor laser elements 11 to 15 are connected to each other in the same manner as the semiconductor laser element 10 and the semiconductor laser element 11. The semiconductor laser element 15 is connected to the current introduction terminal 9b by a metal wire or the like. Note that the plurality of semiconductor laser elements 10 to 15 may be connected in parallel to the current introduction terminals 9a and 9b, respectively.

[0036] The submounts 20 to 25 are bases on which the semiconductor laser elements 10 to 15 are mounted, respectively. In this embodiment, the submounts 20 to 25 are mounted on the laser mounting surfaces 80 a to 85 a, respectively. The submounts 20 to 25 may be fixed with, for example, an inorganic adhesive.

[0037] The submounts 20-25 are block-shaped members made of an insulating material, such as AlN or SiC crystals or ceramic. Electrodes are formed on the upper surfaces of the block-shaped submounts 20-25, and are connected to one electrode of each of the semiconductor laser elements 10-15. The electrodes are made of one or more metal films, such as Ni, Cu, Pt, and Au. The ends of the semiconductor laser elements 10-15, including their light-emitting points, may protrude from the ends of the submounts 20-25. This prevents the laser light from interfering with each submount.

[0038] The multiple fast-axis collimator lenses 30-35 are lenses that collimate the multiple laser beams emitted from the multiple semiconductor laser elements 10-15 in the fast-axis direction (see FIG. 3). The multiple fast-axis collimator lenses 30-35 are disposed between the multiple semiconductor laser elements 10-15 and the multiple prisms 40-45, respectively. The multiple fast-axis collimator lenses 30-35 are mounted, for example, on the multiple submounts 20-25, respectively. The multiple fast-axis collimator lenses 30-35 may be fixed, for example, with an inorganic adhesive. The multiple fast-axis collimator lenses 30-35 collimate the fast-axis components of the multiple laser beams L0A-L5A, respectively. The multiple fast-axis collimator lenses 30-35 may be lenses having a convex cylindrical surface, for example. More specifically, the multiple fast-axis collimator lenses 30-35 can be, for example, plano-convex cylindrical lenses made of glass with an anti-reflection coating formed on their surfaces. In the example shown in FIG. 3 , the positions of the central axes of the fast-axis collimator lenses 30 and 31 are shifted upward (away from the bottom surface 6 a) from the positions of the optical axes of the laser beams L0A and L1A, respectively. Therefore, the propagation direction of the laser beams L0B and L1B emitted from the fast-axis collimator lenses 30 and 31 includes an upward component. In other words, the optical axes of the laser beams L0B and L1B are tilted upward with respect to the YZ plane, which is parallel to the optical axes of the laser beams L0E and L1E, which are reflected by the reflecting mirrors 70 and 71 and coupled into the coupling optical system consisting of the condenser lens 90 and the optical fiber 4. In other words, the optical axes of the laser beams L0B and L1B include an optical axis coupled to the coupling optical system consisting of the condenser lens 90 and the optical fiber 4, and are inclined upward with respect to a plane parallel to the Y-axis direction. In the example of Fig. 3, the optical axis coupled to the coupling optical system is the locus of a light ray connecting the principal point of the condenser lens 90 and the core center of the optical fiber. In this embodiment, the optical axis coupled to the coupling optical system consisting of the condenser lens 90 and the optical fiber 4 is described as the Z-axis direction for the laser beam before it is reflected by the reflecting mirrors 70 and 71, and as the Y-axis direction (negative direction) for the laser beam after it is reflected by the reflecting mirrors 70 and 71.3 shows only the propagation directions of the laser beams L0A to L0E and L1A to L1E, but the propagation directions of the other laser beams (the laser beams emitted from the semiconductor laser elements 12 to 15) are the same as the propagation directions of the laser beams L0A to L0E and L1A to L1E. In the following, the deviation of the position of the central axis of each FAST-axis collimator lens from the position of the optical axis of each laser beam may also be simply expressed as each FAST-axis collimator lens being deviated from each laser beam.

[0039] An example of the characteristics of each fast-axis collimator lens according to this embodiment is shown below. Each fast-axis collimator lens is a cylindrical lens with a focal length of 0.50 mm. The entrance surface (the surface facing each semiconductor laser element) of each fast-axis collimator lens is flat, and the exit surface is convex. Each fast-axis collimator lens has a thickness (dimension in the Z-axis direction in FIG. 1 ) of 0.5 mm, a height (dimension in the X-axis direction in FIG. 1 ) of 0.8 mm, and a width (dimension in the Y-axis direction in FIG. 1 ) of 4.0 mm. The refractive index of each fast-axis collimator lens is 1.8.

[0040] The multiple prisms 40 to 45 are deflection elements that deflect the multiple laser beams in the FAST axis direction (the FAST axis direction of the laser beam immediately after being emitted from each semiconductor laser element). In this embodiment, the multiple prisms 40 to 45 deflect the multiple laser beams in the height direction (X axis direction) from the bottom surface 6a. As shown in FIGS. 2 and 3 , for example, the multiple prisms 40 and 41 each deflect the multiple laser beams L0B and L1B emitted from the multiple FAST axis collimator lenses 30 and 31 in the FAST axis direction and emit the deflected laser beams L0C and L1C. In this embodiment, the multiple prisms 40 and 41 each deflect the multiple laser beams L0B and L1B in the same direction. Each of the multiple prisms 40 to 45 is disposed between each of the multiple FAST axis collimator lenses 30 to 35 and each of the multiple SLOW axis collimator lenses 60 to 65. In this embodiment, the multiple prisms 40 to 45 are mounted on the multiple element mounting surfaces 80 to 85 using a bonding material or the like. The characteristics of each prism are appropriately selected depending on the required deflection angle (i.e., the amount of change in the angle of the optical axis). In this embodiment, a transmissive prism with an apex angle (i.e., the angle between the entrance surface and the exit surface) of 10 degrees and a refractive index of 1.5 is used for each prism. The multiple prisms 40 to 45 can adjust the angles of the optical axes of the multiple laser beams. The detailed effects of the multiple prisms 40 to 45 will be described later.

[0041] The multiple slow-axis collimator lenses 60-65 are lenses that collimate the multiple laser beams in the slow-axis direction. As shown in Figures 2 and 3, for example, the multiple slow-axis collimator lenses 60, 61 collimate the multiple laser beams L0C, L1C emitted from the multiple prisms 40, 41 in the slow-axis direction, respectively, and emit multiple laser beams L0D, L1D. The multiple slow-axis collimator lenses 60-65 are disposed between the multiple fast-axis collimator lenses 30-35 and the reflecting mirrors 70-75, respectively. In this embodiment, the multiple slow-axis collimator lenses 60-65 are disposed on element mounting surfaces 80-85, respectively. The multiple slow-axis collimator lenses 60-65 may be fixed, for example, with an inorganic adhesive.

[0042] As shown in FIG. 2, the laser beams L0C and L1C emitted from the semiconductor laser elements 10 and 11 reach the slow axis collimator lenses 60 and 61 while diverging in the slow axis direction (the Y axis direction in FIG. 2), respectively.

[0043] The multiple laser beams emitted from the multiple slow-axis collimator lenses 60 to 65 have different optical axis positions in the fast-axis direction. This allows the multiple laser beams to be spatially combined by the reflecting mirrors 70 to 75 installed on the element mounting surfaces 80 to 85 at different heights. Here, the multiple laser beams emitted from the multiple slow-axis collimator lenses 60 to 65 may be parallel to each other.

[0044] For example, lenses having convex cylindrical surfaces can be used as the multiple slow-axis collimator lenses 60 to 65. More specifically, for example, plano-convex cylindrical lenses made of glass with an anti-reflection coating formed on the surface can be used as the multiple slow-axis collimator lenses 60 to 65.

[0045] An example of the characteristics of each slow-axis collimator lens according to this embodiment is shown below. Each slow-axis collimator lens is a cylindrical lens with a focal length of 14 mm. The entrance surface (the surface facing each semiconductor laser element) of each slow-axis collimator lens is flat, and the exit surface has a convex shape. Each slow-axis collimator lens has a thickness (dimension in the Z-axis direction in FIG. 1 ) of 3.0 mm, a height (dimension in the X-axis direction in FIG. 1 ) of 3.0 mm, and a width (dimension in the Y-axis direction in FIG. 1 ) of 4.5 mm. In addition, the refractive index of each slow-axis collimator lens is 1.5.

[0046] The multiple reflecting mirrors 70-75 are optical elements that reflect the multiple laser beams emitted from the multiple semiconductor laser elements 10-15, respectively. In this embodiment, the multiple reflecting mirrors 70-75 reflect the multiple laser beams emitted from the multiple slow-axis collimator lenses 60-65, respectively. As shown in FIGS. 2 and 3 , for example, the multiple reflecting mirrors 70, 71 each reflect the multiple laser beams L0D, L1D, thereby emitting multiple laser beams L0E, L1E deflected by 90 degrees. The multiple reflecting mirrors 70-75 are mounted on the multiple element mounting surfaces 80-85, respectively. The multiple reflecting mirrors 70-75 may be fixed with an inorganic adhesive.

[0047] The laser beams L0E and L1E (see FIGS. 2 and 3 ) emitted from the reflecting mirrors 70 to 75, respectively, have parallel propagation directions, do not overlap in the height direction (X-axis direction) from the bottom surface 6 a, and overlap in the Z-axis direction. For example, the laser beam L0E emitted from the reflecting mirror 70 and the laser beam L1E emitted from the reflecting mirror 71 have parallel propagation directions, do not overlap in the height direction (X-axis direction) from the bottom surface 6 a, and overlap in the Z-axis direction. In this embodiment, the laser beams L0E and L1E emitted from the reflecting mirrors 70 to 75, respectively, propagate parallel to the bottom surface 6 a in the negative Y-axis direction.

[0048] The condenser lens 90 is a lens that condenses the plurality of laser beams reflected by the plurality of reflecting mirrors 70 to 75. In this embodiment, the condenser lens 90 condenses the plurality of laser beams so that most of the plurality of laser beams emitted from the condenser lens 90 are incident on the end face of the optical fiber 4 and can propagate through the optical fiber 4. As the condenser lens 90, for example, an aspherical lens can be used.

[0049] The optical fiber 4 is a member that guides the laser light from the inside to the outside of the housing 2. As described above, the plurality of laser beams emitted from the condenser lens 90 are incident on the end face of the optical fiber 4 that is arranged inside the housing 2.

[0050] In this embodiment, as described above, the propagation directions of the multiple laser beams emitted from the multiple reflecting mirrors 70 to 75 are parallel to each other, do not overlap in the height direction from the bottom surface 6a, and overlap in the direction parallel to the bottom surface 6a. This allows spatial multiplexing by the reflecting mirrors 70 to 75 installed on the element installation surfaces 80 to 85 at different heights. Therefore, the multiple laser beams incident on the condenser lens 90 can be efficiently condensed onto the end face of the optical fiber 4 by the condenser lens 90.

[0051] [1-2. Effects, etc.] The effects, etc. of the semiconductor laser device 1 according to this embodiment will be described.

[0052] As described above, the semiconductor laser device 1 according to the present embodiment includes the housing 2 having the flat bottom surface 6a, the plurality of semiconductor laser elements 10 to 15 arranged in the housing 2, the plurality of fast-axis collimator lenses 30 to 35 that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements 10 to 15 in the fast-axis direction, the plurality of prisms 40 to 45 that deflect the plurality of laser beams in the fast-axis direction, and the plurality of slow-axis collimator lenses 60 to 65 that collimate the plurality of laser beams in the slow-axis direction. Each of the plurality of prisms 40 to 45 is arranged between each of the plurality of fast-axis collimator lenses 30 to 35 and each of the plurality of slow-axis collimator lenses 60 to 65. The plurality of laser beams emitted from the plurality of slow-axis collimator lenses 60 to 65 have different optical axis positions in the fast-axis direction (the fast-axis directions of the laser beams emitted from the plurality of semiconductor laser elements 10 to 15).

[0053] In this way, the multiple laser beams emitted from the multiple slow-axis collimator lenses 60 to 65 have different optical axis positions in the fast-axis direction. This allows the multiple laser beams to be spatially multiplexed. In this way, high-power laser beams obtained by superimposing the multiple laser beams can be input into an optical fiber.

[0054] Furthermore, the plurality of prisms 40 to 45 according to this embodiment provide the following effects. The effects of the plurality of prisms 40 to 45 will be described below with reference to FIGS. 4 and 5. FIG. 4 is a side view showing the optical paths of the laser beams L0A to L0C according to this embodiment. FIG. 4 shows the optical path of the laser beam emitted from the light-emitting point 10e until it is emitted from the prism 40. In FIG. 4, the optical axes of the laser beams L0A to L0C are shown by dashed lines, and the contours of the laser beams L0A to L0C are shown by broken lines. Generally, the intensity of laser beams is stronger as they are closer to the optical axis and weaker as they move away from the optical axis. The contour here refers to the beam intensity when the beam intensity is 1 / e of the optical axis position. ２5 shows the relationship between the installation angle of the prism and the deflection angle of the laser beam deflected by the prism. In other words, the angle between the two dashed lines in the light emitted from the light-emitting point 10e of the semiconductor laser element 10 corresponds to the beam divergence angle in the FAST axis direction. FIG. 5 is a graph showing the relationship between the installation angle of the prism and the deflection angle of the laser beam deflected by the prism. The horizontal axis of FIG. 5 indicates the installation angle of the prism (i.e., the rotation angle around the central axis parallel to the Y axis in each diagram), and the vertical axis indicates the deflection angle of the laser beam deflected by the prism (i.e., the amount of change in the angle of the optical axis of the laser beam before and after passing through the prism). FIG. 5 shows the relationship between the installation angle and the deflection angle for four prisms with apex angles (θv) of 10 degrees, 20 degrees, 30 degrees, and 40 degrees.

[0055] As shown in Fig. 4, the position of the central axis of the FAST-axis collimator lens 30 is shifted upward (in a direction away from the bottom surface 6a shown in Fig. 3 and the like) by Δd from the position of the optical axis of the laser beam L0A. As such, as the position of the FAST-axis collimator lens 30 shifts, an angle shift occurs in the optical axis of the laser beam L0B emitted from the FAST-axis collimator lens 30. In the example shown in Fig. 4, the propagation direction of the laser beam L0B emitted from the FAST-axis collimator lens 30 has an upward component. In this embodiment, because the semiconductor laser device 1 has prisms 40 to 45, the angle of the optical axis of each laser beam can be deflected to correct it to a desired angle. 4, the relationship between the incident angle θ11 and the exit angle θ12 of the laser beam L0B incident on the entrance surface of the prism 40, and the relationship between the incident angle θ21 and the exit angle θ22 of the laser beam L0B incident on the exit surface of the prism 40 are each determined based on Snell's law. Therefore, by appropriately selecting the apex angle and refractive index of the prism 40 and appropriately adjusting the installation angle of the prism 40, the deflection angle of the laser beam L0B can be adjusted to a desired angle.

[0056] Furthermore, as shown in Figure 5, the ratio of the change in the deflection angle of the laser light to the change in the installation angle of the prism is relatively small. For example, in the case of a prism with an apex angle of 10 degrees, the change in the deflection angle when the installation angle is changed by 30 degrees from 10 degrees to 40 degrees is approximately 1.3 degrees. In other words, the change in the deflection angle relative to the change in the installation angle is approximately 0.043 times. In contrast, when a reflecting mirror is used, for example, the change in the deflection angle relative to the change in the installation angle is twice as large. In this way, by deflecting the laser light using a prism, it is possible to easily fine-tune the deflection angle of the laser light.

[0057] As shown in Figure 5, the change in the deflection angle of the laser light when the installation angle of the prism is changed depends on the apex angle of the prism. For example, as described above, for a prism with a 10-degree apex angle, the change in the deflection angle when the installation angle is changed by 30 degrees from 10 degrees to 40 degrees is approximately 1.3 degrees. However, for a prism with a 20-degree apex angle, the change in the deflection angle when the installation angle is changed by 30 degrees from 15 degrees to 45 degrees is approximately 2.5 degrees. For a prism with a 30-degree apex angle, the change in the deflection angle when the installation angle is changed by 30 degrees from 22 degrees to 52 degrees is approximately 3.7 degrees. For a prism with a 40-degree apex angle, the change in the deflection angle when the installation angle is changed by 30 degrees from 30 degrees to 60 degrees is approximately 5.3 degrees. In other words, the larger the apex angle of the prism, the larger the change in the deflection angle with respect to the change in installation angle. In this way, the amount of change in the deflection angle can be changed depending on the apex angle of the prism, so by selecting a prism with an appropriate apex angle, the amount of change in the deflection angle relative to a change in the installation angle can be adjusted. For example, by selecting a prism with a small apex angle, the amount of change in the deflection angle relative to a change in the installation angle can be reduced, making it easier to fine-tune the deflection angle. Furthermore, by selecting a prism with a large apex angle, the amount of change in the deflection angle relative to a change in the installation angle can be increased, widening the adjustment range of the deflection angle.

[0058] In the semiconductor laser device 1 according to this embodiment, active alignment can be used as a method for adjusting the installation angle of the prism. That is, the installation angle of each prism is adjusted while each semiconductor laser element is emitting laser light. Then, after the adjustment of the installation angle of each prism is completed, each prism is fixed to the corresponding element mounting surface. To fix each prism, for example, a bonding material such as a photosensitive adhesive that hardens when irradiated with ultraviolet light can be used. In this way, by applying a bonding material between each prism and each element mounting surface before active alignment and then irradiating the bonding material with ultraviolet light after active alignment is completed, deviation in the installation angle when each prism is fixed can be suppressed.

[0059] Furthermore, in the semiconductor laser device 1, the multiple semiconductor laser elements may include a first semiconductor laser element that emits a first laser beam. The multiple fast-axis collimator lenses may include a first fast-axis collimator lens that collimates the first laser beam in the fast-axis direction. The multiple prisms may include a first prism that deflects the first laser beam. The central axis of the first fast-axis collimator lens may be shifted from the optical axis of the first laser beam in a first direction along the fast-axis direction, and the first prism may deflect the first laser beam in a direction opposite to the first direction. This allows the first prism to cancel out at least a portion of the deflection of the first laser beam in the fast-axis direction by the first fast-axis collimator lens.

[0060] Furthermore, in the semiconductor laser device 1, each of the plurality of prisms 40 to 45 may deflect the plurality of laser beams in the same direction.

[0061] The semiconductor laser device 1 may also include a plurality of reflecting mirrors 70 to 75 that reflect the plurality of laser beams emitted from the plurality of slow axis collimator lenses 60 to 65, respectively.

[0062] This allows the multiple laser beams to be deflected so that their positions in the direction perpendicular to the optical axis direction and the direction in which they are aligned can be overlapped. At this time, the multiple laser beams emitted from the multiple reflecting mirrors 70-75 are collimated laser beams and form a bundle of parallel laser beams. Furthermore, the optical axes are precisely adjusted by the prisms 40-45. Therefore, all of the multiple laser beams are precisely parallel to the optical axis toward the optical fiber 4. In other words, the bundle of laser beams containing multiple laser beams can be a bundle of laser beams with a small beam parameter product and high radiance. This bundle of laser beams is incident on the optical fiber 4 with high coupling efficiency by the condenser lens 90. Therefore, a laser beam with high optical output can be emitted from the optical fiber 4 of the semiconductor laser device 1.

[0063] In addition, in the semiconductor laser device 1, the housing 2 may be an airtight package that hermetically seals the multiple semiconductor laser elements 10 to 15, the multiple fast axis collimator lenses 30 to 35, the multiple prisms 40 to 45, and the multiple slow axis collimator lenses 60 to 65.

[0064] This makes it possible to prevent foreign matter and the like from entering the housing 2. Therefore, adverse effects on laser light caused by the accumulation of foreign matter and the like can be suppressed, and the reliability of the semiconductor laser device 1 can be improved.

[0065] [1-3. Modification 1] A semiconductor laser device according to Modification 1 of the present embodiment will be described. This modification differs from the semiconductor laser device 1 according to Embodiment 1 in the direction of positional deviation of each FAST axis collimator lens, but is the same in other respects. The semiconductor laser device according to this modification will be described below with reference to FIG. 6, focusing on the differences from the semiconductor laser device 1 according to Embodiment 1. FIG. 6 is a side view showing the optical paths of laser beams L0A to L0E and L1A to L1E in the semiconductor laser device according to this modification.

[0066] In the example shown in Figure 6, the positions of the central axes of the FAST-axis collimator lenses 30 and 31 are shifted downward (toward the bottom surface 6a) from the positions of the optical axes of the laser beams L0A and L1A, respectively. Therefore, the propagation directions of the laser beams L0A and L1A emitted from the FAST-axis collimator lenses 30 and 31 have a downward component. In other words, the optical axes of the laser beams L0A and L1A are tilted downward with respect to the YZ plane, which is parallel to the optical axis of the laser beam reflected by the reflecting mirror and coupled to the coupling optical system consisting of the condenser lens 90 and the optical fiber 4. Note that while Figure 6 only shows the propagation directions of the laser beams L0A to L0E and L1A to L1E, the propagation directions of the other laser beams are similar to the propagation directions of the laser beams L0A to L0E and L1A to L1E.

[0067] In such a case, the propagation direction of each laser beam can be adjusted to a desired direction by each prism. In the example shown in Fig. 6, each prism deflects the propagation direction of each laser beam to a direction parallel to the Z-axis direction. As such a prism, for example, a prism having a shape similar to that of the prism according to the first embodiment, but turned upside down, can be used.

[0068] The semiconductor laser device according to this modification also achieves the same effects as those of the semiconductor laser device 1 according to the first embodiment.

[0069] In the semiconductor laser device according to this modification, an example has been shown in which the central axes of the fast-axis collimator lenses are shifted downward from the optical axes of the laser beams, but the configuration of the semiconductor laser device according to this modification is not limited to this. For example, the central axes of some fast-axis collimator lenses may be shifted upward from the optical axes of the laser beams, and the central axes of other fast-axis collimator lenses may be shifted downward from the optical axes of the laser beams. Even in such a case, the propagation direction of the laser beam can be adjusted to a desired direction by using an appropriate prism depending on the propagation direction of the laser beam.

[0070] [1-4. Modification 2] A semiconductor laser device according to Modification 2 of the present embodiment will be described. This modification differs from the semiconductor laser device 1 according to the first embodiment in that the propagation direction of the laser light emitted from each semiconductor laser element is inclined with respect to the bottom surface 6a, but is the same in other respects. The semiconductor laser device according to this modification will be described below with reference to FIG. 7, focusing on the differences from the semiconductor laser device 1 according to the first embodiment. FIG. 7 is a side view showing the optical paths of the laser light L0A-L0E and L1A-L1E in the semiconductor laser device according to this modification.

[0071] The propagation direction of the laser beams L0A, L1A emitted from the semiconductor laser elements 10, 11 according to this modification has a component in the height direction (X-axis direction) from the bottom surface 6 a. In the example shown in FIG. 7 , the propagation direction of the laser beams L0A, L1A has a component upward.

[0072] The semiconductor laser device according to this modification includes a multi-stage base 108. The multi-stage base 108 has a plurality of element mounting surfaces 80, 81 and laser mounting surfaces 180a, 181a. The laser mounting surfaces 180a, 181a according to this modification are inclined with respect to the bottom surface 6a. As a result, the propagation direction of laser light L0A, L1A from the semiconductor laser elements 10, 11 respectively mounted on the laser mounting surfaces 180a, 181a includes a component in the height direction from the bottom surface 6a.

[0073] When the semiconductor laser elements are horizontally mounted on the multistage base 8 as in the present embodiment and Modification 1, in order to make the laser beams parallel to the Z-axis direction, it was necessary to reverse the upside down of the prisms used depending on the direction of displacement of the FAST-axis collimator lenses. In Modification 2 shown in FIG. 7 , the propagation direction of the laser beams L0A and L1A from the semiconductor laser elements 10 and 11 is a direction upward from the bottom surface 6 a. In this case, regardless of whether the FAST-axis collimator lenses 30 and 31 are displaced upward or downward, the optical axis directions of the laser beams L0B and L1B that have passed through the FAST-axis collimator lenses 30 and 31 can be made to direct upward. Specifically, in FIG. 7 , the semiconductor laser element 10 is mounted parallel to the laser mounting surface 180 a, which increases in height from the bottom surface 6 a as it approaches the prism 40 (as it proceeds in the positive direction of the Z-axis), and the FAST-axis collimator lens 30 is displaced downward with respect to the laser beam L0A. As a result, the laser beam L0B is deflected downward relative to the laser beam L0A, but propagates in a direction tilted upward relative to the Z-axis direction. The semiconductor laser element 11 is installed parallel to the laser installation surface 181a. The laser installation surface 181a is tilted parallel to the laser installation surface 180a. That is, the tilt angle of the laser installation surface 181a relative to the bottom surface 6a is the same as the tilt angle of the laser installation surface 180a. Furthermore, because the fast-axis collimator lens 31 is shifted upward relative to the laser beam L1A, the laser beam L1B is deflected upward relative to the laser beam L1A. The laser beam L1B propagates in a direction tilted upward relative to the Z-axis direction. Since both the laser beam L0B and the laser beam L1B are directed upward relative to the Z-axis, the propagation direction of each laser beam after passing through each prism can be deflected parallel to the Z-axis direction by installing each prism in the same orientation (vertical orientation) as in the first embodiment and adjusting only the installation angle. That is, regardless of the direction of deviation of the installation positions of the fast axis collimator lenses, the multiple laser beams can be made parallel in the Z-axis direction by the multiple prisms that are installed in the same direction.

[0074] Although not shown in the figure, if the propagation direction of the laser beams L0A and L1B from the semiconductor laser elements 10 and 11 is downward relative to the Z-axis direction, by using prisms 40 and 41 installed in the same orientation as in variant example 1, the propagation direction of the laser beams L0C and L1C emitted from the prisms 40 and 41 can be deflected in a direction parallel to the Z-axis direction in the same manner as described above.

[0075] Furthermore, according to the semiconductor laser device of this modified example, the height of each laser beam from the bottom surface 6a can be adjusted by adjusting the position of each prism in the optical axis direction of each laser beam.

[0076] [1-5. Modification 3] A semiconductor laser device according to Modification 3 of the present embodiment will be described. The semiconductor laser device according to this modification differs from the semiconductor laser device 1 according to embodiment 1 in that a prism is further provided between each prism and each slow-axis collimator lens, but is the same in other respects. The semiconductor laser device according to this modification will be described below with reference to FIG. 8, focusing on the differences from the semiconductor laser device 1 according to embodiment 1. FIG. 8 is a side view showing the optical paths of laser beams L0A to L0E and L1A to L1E in the semiconductor laser device according to this modification.

[0077] As shown in FIG. 8, the semiconductor laser device according to this modification includes a plurality of rear prisms 50 and 51 .

[0078] The rear prisms 50, 51 are deflection elements that deflect the laser beams L0C, L1C emitted from the prisms 40, 41 in the fast axis direction. In other words, the rear prisms 50, 51 deflect the laser beams L0C, L1C in the height direction (X axis direction) from the bottom surface 6a in the opposite direction to the prisms 40, 41. Each of the rear prisms 50-51 is disposed between each of the prisms 40, 41 and each of the slow axis collimator lenses. In this modification, the rear prisms 50, 51 are mounted on the element mounting surfaces 80, 81 using a bonding material or the like. The characteristics of each rear prism are selected appropriately depending on the required deflection angle, etc.

[0079] The semiconductor laser device according to this modification also achieves the same effects as those of the semiconductor laser device 1 according to the first embodiment.

[0080] The semiconductor laser device according to this modification also includes a plurality of rear-stage prisms 50, 51. The plurality of semiconductor laser elements 10, 11 include a first semiconductor laser element that emits a first laser beam, the plurality of prisms 40, 41 include a first prism that deflects the first laser beam, and the plurality of rear-stage prisms 50, 51 include a first rear-stage prism that deflects the first laser beam. The direction of deflection of the first laser beam by the first rear-stage prism is opposite to the direction of deflection of the first laser beam by the first prism. Here, each of the semiconductor laser elements 10, 11 according to this modification is an example of a first semiconductor laser element, each of the plurality of prisms 40, 41 is an example of a first prism, and each of the plurality of rear-stage prisms 50, 51 is an example of a first rear-stage prism. As described above, the directions of deflection of the laser beams L0C and L1C by the multiple rear prisms 50 and 51 are opposite to the directions of deflection of the laser beams L0B and L1B by the multiple prisms 40 and 41, respectively. By providing the rear prisms 50 and 51, the semiconductor laser device according to this modification can increase the degree of freedom in adjusting the angle of the optical axis of each laser beam. For example, in this modification, the rear prisms can be provided to adjust the angle of the optical axis of each laser beam and the optical axis position of each laser beam in the FAST axis direction (the FAST axis direction of the laser beam immediately after being emitted from each semiconductor laser element). In FIG. 8 , the semiconductor laser elements 10 and 11 are disposed parallel to the bottom surface 6 a, and the laser beams L0A and L1A are parallel to the bottom surface 6 a. Furthermore, because the FAST axis collimator lenses are shifted upward relative to the laser beams, the laser beams are deflected upward. That is, the heights of the optical axes of laser beams L0B and L1B emitted from fast-axis collimator lenses 30 and 31, respectively, from bottom surface 6a gradually increase as they propagate. Laser beams L0B and L1B are deflected downward by prisms 40 and 41, respectively. As a result, the heights of laser beams L0C and L1C from bottom surface 6a gradually decrease. Furthermore, laser beams L0C and L1C are deflected again by rear-stage prisms 50 and 51, respectively.As a result, the heights of the laser beams L0C2 and L1C2 from the bottom surface 6 a become the same as the heights of the laser beams L0A and L1A, respectively, and the optical axes of the laser beams L0C2 and L1C2 become parallel to the bottom surface 6 a. In this way, by appropriately selecting the prisms 40 and 41 and the rear-stage prisms 50 and 51 in response to the deviation in the height direction of each FAST axis collimator lens, the heights of the laser beams L0C2 and L1C2 from the base can be made the same as the heights of L0A and L1A, and the optical axes of the laser beams L0C2 and L1C2 can be made parallel to the bottom surface 6 a.

[0081] Here, Figure 8 shows that the directions of deflection of the multiple laser beams L0C, L1C by the multiple rear-stage prisms 50, 51 are the same when viewed from the Y-axis direction. Note that the directions of deflection of the multiple laser beams L0C, L1C by the multiple rear-stage prisms 50, 51 do not have to be the same, and the multiple laser beams L0C2, L1C2 do not have to be parallel. It is sufficient that the relationship between the direction of deflection by the prism and the direction of deflection by the rear-stage prism is maintained in each of the multiple optical systems corresponding to the multiple laser beams. For example, in the semiconductor laser device shown in Figure 8, the prism 40 and the rear-stage prism 50 may be rotated 180 degrees in the YZ plane.

[0082] The semiconductor laser device according to this modification includes a rear prism corresponding to each laser beam. That is, the number of laser beams and the number of rear prisms are the same, but the number of rear prisms is not limited to this. The number of rear prisms may be one or more. That is, the semiconductor laser device according to this modification may include at least one rear prism corresponding to at least one laser beam.

[0083] [1-6. Modification 4] A semiconductor laser device according to Modification 4 of the present embodiment will be described. The semiconductor laser device according to this modification differs from the semiconductor laser device 1 according to embodiment 1 in the configuration of the installation surface on which each prism is installed, but is the same in other respects. The semiconductor laser device according to this modification will be described below with reference to FIG. 9, focusing on the differences from the semiconductor laser device 1 according to embodiment 1. FIG. 9 is a side view showing the configuration of a prism installation surface 80d in the semiconductor laser device according to this modification.

[0084] As shown in FIG. 9 , the prism 40 according to this modification is mounted on a prism mounting surface 80d. The prism mounting surface 80d has a curved surface. In this modification, the prism mounting surface 80d has a cylindrical, concave curved surface. Meanwhile, the bottom surface of the prism 40 (the surface facing the prism mounting surface 80d) is rectangular. By mounting a prism 40 having such a bottom surface on the curved prism mounting surface 80d, the mounting angle of the prism 40 can be adjusted with the two edges 40a and 40b of the bottom surface of the prism 40 in contact with the prism mounting surface 80d. This stabilizes the mounting angle of the prism 40, making it easy to adjust the mounting angle. As described above, the prism 40 is fixed to the prism mounting surface 80d using a bonding material B0, such as a photosensitive adhesive, as shown in FIG. 9 . Alternatively, the prism mounting surface 80d may have a cylindrical, convex curved surface. In this case, it is possible to bring the bottom surface of the prism 40 and the prism mounting surface 80d into contact at a linear contact portion, thereby making it possible to adjust the installation angle of the prism 40 while the bottom surface of the prism 40 and the prism mounting surface 80d are in contact at the linear contact portion.

[0085] In this modification, the shape of the prism mounting surface 80d is cylindrical, but the shape of the prism mounting surface 80d is not limited to this. For example, the cross-sectional shape of the prism mounting surface 80d (the shape in a cross section parallel to the ZX plane) may be elliptical.

[0086] Alternatively, the bottom surface of the prism 40 may have a concave curved shape, and the prism mounting surface 80d may have a convex portion with a rectangular top surface. In this case, too, the installation angle of the prism 40 can be adjusted with two sides of the top surface of the prism mounting surface 80d in contact, achieving the same effect as this modification. Furthermore, even if the bottom surface of the prism 40 has a convex curved shape, the installation angle of the prism 40 can be adjusted with the bottom surface of the prism 40 and the prism mounting surface 80d in contact at a linear contact portion.

[0087] (Embodiment 2) A semiconductor laser device according to embodiment 2 will be described. The semiconductor laser device according to this embodiment differs from the semiconductor laser device 1 according to embodiment 1 in the installation mode of each prism, but is the same in other respects. The semiconductor laser device according to this embodiment will be described below, focusing on the differences from the semiconductor laser device 1 according to embodiment 1.

[0088] [2-1. Configuration] The configuration of the semiconductor laser device according to this embodiment will be described with reference to Fig. 10 and Fig. 11. Fig. 10 and Fig. 11 are a perspective view and a plan view, respectively, showing the configuration of a semiconductor laser device 201 according to this embodiment.

[0089] 10 and 11 , a semiconductor laser device 201 according to the present embodiment includes a plurality of semiconductor laser elements 10, 11, a plurality of submounts 20, 21, a plurality of fast-axis collimator lenses 30, 31, a plurality of prisms 40, 41, a plurality of slow-axis collimator lenses 60, 61, a plurality of reflecting mirrors 70, 71, and a multistage base 8. Although not shown in FIGS. 10 and 11 , the semiconductor laser device 201 further includes a housing 2, current input terminals 9 a, 9 b, an optical fiber 4, and a condenser lens 90, similar to the semiconductor laser device 1 according to the first embodiment.

[0090] As shown in Figures 10 and 11, the multi-stage base 8 has multiple steps. Each of the multiple steps of the multi-stage base 8 has an element mounting surface (element mounting surface 80 or element mounting surface 81) parallel to the bottom surface 6a (see Figure 1, etc.) and a side surface (side surface 80s or side surface 81s) erected on the element mounting surface. In this embodiment, each of the multiple prisms 40, 41 is mounted on the side surface. That is, the prism 40 is mounted on the side surface 80s, and the prism 41 is mounted on the side surface 81s. Furthermore, the slow axis of each laser light incident on each of the multiple prisms 40, 41 is perpendicular to the side surface on which the prism is mounted.

[0091] In this embodiment, as shown in FIG. 11, the prisms 40 and 41 are fixed to the side surfaces 80s and 81s, respectively, with a bonding material B0.

[0092] The effects of the semiconductor laser device 201 according to this embodiment will be described with reference to Fig. 12 and Fig. 13. Fig. 12 and Fig. 13 are diagrams respectively showing the state of the prism 40 before and after the bonding material B0 has hardened when the prism 40 is fixed to the element mounting surface 80 using the bonding material B0. In Fig. 13, the state of the prism before the bonding material B0 has hardened is also shown by a dashed line.

[0093] 12 and 13, the bonding material B0 shrinks as it hardens. Therefore, as shown in FIG. 13, when the prism 40 is mounted on the element mounting surface 80, the mounting angle of the prism 40 may change before and after hardening. In other words, as the bonding material B0 hardens, the prism 40 may rotate around an axis parallel to the Y-axis direction. Therefore, as the bonding material B0 hardens, the optical axis of the laser light may change.

[0094] On the other hand, in the present embodiment, the multiple prisms 40 and 41 are installed on the side surfaces 80s and 81s, respectively, so that rotation of each prism about an axis parallel to the Y-axis direction can be suppressed, and therefore, change in the deflection angle of each laser beam in the FAST-axis direction of each prism due to hardening of the bonding material B0 can be suppressed.

[0095] Here, each of the side surfaces 80s, 81s can be perpendicular to the slow axis direction (Y axis direction) of each laser beam. In this case, the rotation direction of the prisms 40, 41 installed on the side surfaces 80s, 81s can be limited to the rotation direction around an axis parallel to the Y axis direction, so that the amount of deflection in only the fast axis direction can be adjusted by rotating the prisms 40, 41.

[0096] Furthermore, the surfaces of each prism facing the respective side surfaces can be flat and parallel to the respective side surfaces, so that each prism can be stably fixed to the respective side surfaces without the need for tilting as shown in Fig. 13. Furthermore, by fixing the surfaces of each prism facing the respective side surfaces parallel to the respective side surfaces, it is possible to prevent each prism from tilting relative to the optical axis as the bonding material B0 hardens.

[0097] [2-2. Modifications] A semiconductor laser device according to a modification of this embodiment will be described. The semiconductor laser device according to this modification differs from the semiconductor laser device 201 according to the second embodiment in the configuration of the multi-stage base, but is the same in other respects. The semiconductor laser device according to this modification will be described below with reference to FIGS. 14 and 15, focusing on the differences from the semiconductor laser device 201 according to the second embodiment. FIGS. 14 and 15 are a perspective view and a plan view, respectively, showing the configuration of a semiconductor laser device 201a according to this modification.

[0098] As shown in Figures 14 and 15, a semiconductor laser device 201a according to this modified example includes a plurality of semiconductor laser elements 10, 11, a plurality of submounts 20, 21, a plurality of fast-axis collimator lenses 30, 31, a plurality of prisms 40, 41, a plurality of slow-axis collimator lenses 60, 61, a plurality of reflecting mirrors 70, 71, and a multi-stage base 8a.

[0099] 14 and 15 , the multi-stage base 8a has a plurality of steps. Each of the steps of the multi-stage base 8a has an element mounting surface (element mounting surface 80 or element mounting surface 81) parallel to the bottom surface 6a (see FIG. 1 , etc.) and a side surface (side surface 80s or side surface 81s) erected on the element mounting surface. In this embodiment, the side surfaces 80s and 81s are perpendicular to the element mounting surfaces 80 and 81, respectively. Each of the steps of the multi-stage base 8a has a protrusion (protrusion 80p or protrusion 81p) protruding from the element mounting surface and facing the side surface.

[0100] In this modification, each of the multiple prisms 40 and 41 is disposed on the side surface and the protrusion. That is, the prism 40 is disposed on the side surface 80s and the protrusion 80p, and the prism 41 is disposed on the side surface 81s and the protrusion 81p.

[0101] The distance between each protrusion and each side surface is greater than the width of each prism.

[0102] In this modification, as shown in FIG. 15, the prism 40 is fixed to the side surface 80s and the protrusion 80p with a bonding material B0, and the prism 41 is fixed to the side surface 81s and the protrusion 81p with a bonding material B0.

[0103] This increases the bonding area between each prism and the multi-stage base 8a, thereby increasing the bonding strength of each prism to the multi-stage base 8a.

[0104] The plurality of protrusions 80p, 81p may have surfaces that face the side surfaces 80s, 81s and are parallel to the side surfaces 80s, 81s, respectively, which makes it easier to install the prisms.

[0105] Furthermore, each protrusion may have a surface flush with the side surface of the adjacent step (the lower step among the adjacent steps). In other words, each protrusion may form part of the side surface of the adjacent step. This allows each protrusion to be used as a mounting surface for a prism placed on the other step. This further increases the bonding area of ​​the prism.

[0106] Third Embodiment A semiconductor laser device according to the third embodiment will be described. The semiconductor laser device according to the third embodiment differs from the semiconductor laser device 201a according to the modified example of the second embodiment in that each semiconductor laser element is arranged in an airtight package, but is the same in other respects. The semiconductor laser device according to the third embodiment will be described below with reference to FIGS. 16 and 17, focusing on the differences from the semiconductor laser device 201a according to the modified example of the second embodiment. FIG. 16 is a perspective view showing the configuration of a semiconductor laser device 301 according to the present embodiment. FIG. 17 is a side view showing the configuration of the semiconductor laser element 10 and other components according to the present embodiment. Note that FIG. 17 shows a cross section of the airtight package P10 to show the internal structure of the airtight package P10.

[0107] 16, the semiconductor laser device 301 according to the present embodiment includes a plurality of airtight packages P10, P11, a plurality of prisms 40, 41, a plurality of slow-axis collimator lenses 60, 61, a plurality of reflecting mirrors 70, 71, and a multi-stage base 308. Although not shown in FIGS. 16 and 17, the semiconductor laser device 301 further includes a housing 2, current input terminals 9a, 9b, an optical fiber 4, and a condenser lens 90, similar to the semiconductor laser device 1 according to the first embodiment.

[0108] The multi-stage base 308 according to this embodiment differs from the multi-stage base 8a according to the modified example of the second embodiment in that each of the element mounting surfaces 80 and 81 includes a laser mounting surface.

[0109] 17, the hermetic package P10 is a package that hermetically seals the semiconductor laser element 10 and the fast-axis collimator lens 30 onto which the laser light emitted from the semiconductor laser element is incident. In this embodiment, the hermetic package P10 also hermetically seals the submount 20. The hermetic package P10 has a first package P21, a light-transmitting window P17, and a lid P02. Furthermore, as shown in FIG. 16, the hermetic package P10 further has an anode extraction electrode P31 and a cathode extraction electrode P34.

[0110] The first package P21 is a container that constitutes the main body of the airtight package P10 and has two openings.

[0111] The light-transmitting window P17 is a light-transmitting member that transmits the laser light L0B, and covers one opening of the first package P21.

[0112] The lid P02 is a cover that covers the other opening of the first package P21.

[0113] The anode output electrode P31 is an electrode for connection to a current introducing terminal 9a arranged outside the airtight package P10 and is arranged outside the first package P21. The cathode output electrode P34 is an electrode for connection to a current introducing terminal 9b arranged on the top surface of the first package P21 and is arranged on the top surface of the first package P21.

[0114] The anode lead electrode P31 and the cathode lead electrode P34 are electrically connected to the semiconductor laser element 10 arranged inside the first package P21 by metal wiring, via electrodes, and metal wires.

[0115] The semiconductor laser element 10, the submount 20, and the fast axis collimator lens 30 are fixed in an airtight package P10 with an inorganic adhesive.

[0116] The hermetic package P11 is a package that hermetically seals the semiconductor laser element 11 and the fast-axis collimator lens 31 (see FIG. 14 etc. for the semiconductor laser element 11 and the fast-axis collimator lens 31). In this embodiment, the hermetic package P11 also hermetically seals the submount 21 (see FIG. 14 etc. for the submount 21). The hermetic package P11 has a configuration similar to that of the hermetic package P10.

[0117] The semiconductor laser device 301 according to the present embodiment can prevent foreign matter such as organic matter from entering the periphery of each semiconductor laser element. In particular, when the semiconductor laser element 10 includes an AlGaInN-based semiconductor and emits laser light having a wavelength ranging from blue light to ultraviolet light, deterioration of the semiconductor laser element 10 caused by organic matter adhering to the light-emitting point 10 e of each semiconductor laser element 10 due to a photochemical reaction can be prevented.

[0118] In this embodiment, one set of semiconductor laser elements and a fast-axis collimator lens is hermetically sealed in each hermetic package, but the configuration of the hermetic packages is not limited to this. For example, each hermetic package may hermetically seal a plurality of sets of semiconductor laser elements and fast-axis collimator lenses.

[0119] As described above, the semiconductor laser device may include one or more hermetic packages. Each of the one or more hermetic packages may hermetically seal one or more semiconductor laser elements among the plurality of semiconductor laser elements and one or more FAST-axis collimator lenses among the plurality of FAST-axis collimator lenses, onto which one or more laser beams emitted from the one or more semiconductor laser elements are respectively incident. Each of the one or more semiconductor laser elements and each of the one or more FAST-axis collimator lenses may be fixed with an inorganic adhesive. Each of the one or more hermetic packages may have a light-transmitting window, and the one or more laser beams emitted from the one or more semiconductor laser elements may pass through the light-transmitting window.

[0120] (Fourth Embodiment) A semiconductor laser device according to the fourth embodiment will be described. The semiconductor laser device according to this embodiment differs from the semiconductor laser device according to the second modification of the first embodiment in that a plurality of semiconductor laser elements are installed on the same plane, but is the same in other respects. The semiconductor laser device according to this embodiment will be described below with reference to FIGS. 18 and 19, focusing on the differences from the semiconductor laser device according to the second modification of the first embodiment. FIGS. 18 and 19 are a perspective view and a side view, respectively, showing the configuration of a semiconductor laser device 401 according to this embodiment. FIG. 19 is a side view showing the configuration of a semiconductor laser element 10 and the like according to this embodiment.

[0121] 18, a semiconductor laser device 401 according to this embodiment includes a housing 2, a plurality of semiconductor laser elements 10-12, a plurality of reflecting mirrors 70-72, a condenser lens 90, a plurality of element mounting surfaces 80-82, a plurality of submounts 20-22, a plurality of fast-axis collimator lenses 30-32, a plurality of prisms 40-42, a plurality of slow-axis collimator lenses 60-62, a laser mounting surface 407a, and an optical fiber 4. Note that current introduction terminals and the like are not shown in FIGS.

[0122] In this embodiment, the semiconductor laser device 401 includes a multi-stage base 408 having a plurality of element mounting surfaces 80 to 82 and a laser mounting surface 407a.

[0123] The multi-step base 408 has a lower surface 408ba and is placed on the bottom surface 6a so that the lower surface 408ba is parallel to the bottom surface 6a. The multi-step base 408 has a plurality of stair-like steps. Each of the plurality of steps of the multi-step base 408 has a surface parallel to the lower surface 408ba, and the surfaces parallel to the lower surface 408ba correspond to each of the plurality of element mounting surfaces 80-82. Therefore, each of the plurality of element mounting surfaces 80-82 is parallel to the bottom surface 6a. Furthermore, each of the plurality of element mounting surfaces 80-82 is parallel to one another and is not on the same plane.

[0124] The semiconductor laser elements 10-12 according to this embodiment are mounted on a laser mounting surface 407a that is inclined with respect to the bottom surface 6a. The laser mounting surface 407a is inclined, for example, at an angle of 5 degrees to 20 degrees with respect to the bottom surface 6a. As a result, as shown in FIG. 19 , the propagation direction of the laser beams L0A-L2A emitted from the semiconductor laser elements 10-12 has a component in the height direction from the bottom surface 6a. The propagation direction of the laser beams L0A-L2A emitted from the semiconductor laser elements 10-12 has a component in the upward direction (positive direction in the X-axis direction). In this embodiment, the semiconductor laser elements 10-12 are arranged on the same plane. This facilitates the mounting of the semiconductor laser elements 10-12.

[0125] The multiple fast axis collimator lenses 30 to 32 collimate the multiple laser beams L0A to L2A emitted from the multiple semiconductor laser elements 10 to 12, respectively, in the fast axis direction, and emit multiple laser beams L0B to L2B collimated in the fast axis direction.

[0126] The plurality of prisms 40 to 42 deflect the plurality of laser beams L0B to L2B in the fast axis direction (the fast axis direction of the laser beam immediately after being emitted from each semiconductor laser element), and emit the plurality of laser beams L0C to L2C.

[0127] The plurality of slow-axis collimator lenses 60 to 62 collimate the plurality of laser beams L0C to L2C in the slow-axis direction, respectively, and emit the plurality of collimated laser beams L0D to L2D.

[0128] The plurality of reflecting mirrors 70 to 72 reflect the plurality of laser beams L0D to L2D, respectively, and emit the plurality of laser beams L0E to L2E.

[0129] In this embodiment, the semiconductor laser elements 10-12 are arranged at the same height. That is, the optical axes of the laser beams L0A-L2A immediately after being emitted from the semiconductor laser elements 10-12 are at the same height (that is, the heights of the light-emitting points 10e-12e are at the same height). In this embodiment, by changing the distance of each of the prisms 40-42 from each of the semiconductor laser elements 10-12, the heights of the laser beams L0C-L2C emitted from the prisms 40-42 from the bottom surface 6a can be made to differ.

[0130] The distance in the Z-axis direction of each of the prisms 40-42 from the corresponding semiconductor laser element increases as the height of each prism from the bottom surface 6a increases. This allows the distance of each of the prisms 40-42 from the corresponding semiconductor laser element to vary depending on the height at which each prism is installed. The prisms 40-42 are installed near the ends of the element installation surfaces 80-82, respectively, that are closer to the semiconductor laser elements 10-12. Note that the prisms 40-42 may also be installed in areas on the laser installation surface 407a near the ends of each element installation surface.

[0131] The distance from each semiconductor laser element to each element mounting surface increases as the height of each element mounting surface from the bottom surface 6a increases. Furthermore, as the height of each element mounting surface from the bottom surface 6a increases, the length of each element mounting surface in the propagation direction (Z-axis direction) of each laser beam (L0C-L2C, L0D-L2D) decreases. In other words, the element mounting surfaces 80-82 that are higher from the bottom surface 6a have shorter lengths in the propagation direction (Z-axis direction) of the laser beam. The end of each element mounting surface is directly connected to the laser mounting surface 407a. This allows each laser beam to propagate along the laser mounting surface 407a and each element mounting surface. This reduces the possibility of each laser beam being blocked by the multi-stage base 408. Furthermore, by arranging each optical element on the laser mounting surface 407a or each element mounting surface, each laser beam can be controlled. The laser mounting surface 407a is inclined with respect to the bottom surface 6a, and the height from the bottom surface 6a decreases with increasing distance from the end of each element mounting surface.

[0132] The heights of the reflecting mirrors 70 to 72 from the bottom surface 6a at their installation positions are different from one another. The reflecting mirrors 70, 71, and 72 are higher in height from the bottom surface 6a at their installation positions in this order.

[0133] For example, when the light-emitting point 10e of the semiconductor laser element 10 is used as a reference, the distance in the first direction (the X-axis direction in this embodiment) from the light-emitting point 10e of the semiconductor laser element 10 to the optical axis of the laser light L0D incident on the reflecting mirror 70 is different from the distance in the first direction from the light-emitting point 10e of the semiconductor laser element 10 to the optical axis of the laser light L1D incident on the reflecting mirror 71. Similarly, the distances in the first direction (the X-axis direction in this embodiment) from the light-emitting point 10e of the semiconductor laser element 10 to the optical axes of the laser light L0D, L1D incident on the reflecting mirrors 70, 71, respectively, are different from each other.

[0134] The laser beams L0C to L2C and L0D to L2D propagate between the prisms 40 to 42 and the reflecting mirrors 70 to 72 in the positive direction of the Z axis, parallel to the bottom surface 6a, and parallel to the element mounting surfaces 80 to 82. The laser beams L0D to L2D also propagate parallel to one another.

[0135] Furthermore, the laser beams L0B to L2B propagate parallel to the laser mounting surface 407a between the semiconductor laser elements 10 to 12 and the prisms 40 to 42. Furthermore, the laser beams L0B to L2B propagate parallel to one another between the semiconductor laser elements 10 to 12 and the prisms 40 to 42.

[0136] Furthermore, the laser beams L0E to L2E propagate between the reflecting mirrors 70 to 72 and the condenser lens 90 in the negative direction of the Y axis, parallel to the bottom surface 6a.

[0137] Here, the spot size in the slow axis direction of each laser beam emitted from the multiple slow axis collimator lenses 60 to 62 increases as the optical path length from each semiconductor laser element to each slow axis collimator lens increases. In order to make the spot sizes in the slow axis direction of each laser beam emitted from the multiple slow axis collimator lenses 60 to 62 uniform, the optical path lengths from each of the multiple slow axis collimator lenses 60 to 62 to each of the multiple semiconductor laser elements 10 to 12 may be made uniform. Accordingly, the positions of each of the slow axis collimator lenses 60 to 62 in the Z axis direction differ. As shown in FIG. 19 , the positions of the slow axis collimator lens 60 and the slow axis collimator lens 62 in the Z axis direction differ by ΔL.

[0138] As described above, the distance in the Z-axis direction from each slow-axis collimator lens to each semiconductor laser element may become smaller as the height of each slow-axis collimator lens from the bottom surface 6 a increases, which makes it possible to make the optical path lengths from each slow-axis collimator lens to each semiconductor laser element uniform.

[0139] The semiconductor laser device 401 having the above-described configuration also achieves the same effects as the semiconductor laser device 1 according to embodiment 1. As described above, in the semiconductor laser device 401 according to this embodiment, the plurality of semiconductor laser elements 10 to 12 are placed on the same plane, which facilitates the mounting of the plurality of semiconductor laser elements 10 to 12. For example, when wiring the plurality of semiconductor laser elements 10 to 12 using metal wires to supply current to the semiconductor laser elements, the heights of the bond portions of the wire bonds can be made uniform, which facilitates wire bonding.

[0140] Furthermore, when a heat sink is connected to the bottom 6 and heat is dissipated from the bottom 6, the heat dissipation characteristics change depending on the distance from the semiconductor laser element to the bottom surface 6a. In this embodiment, by reducing the difference in height from the bottom surface 6a of the plurality of semiconductor laser elements 10 to 12, it is possible to reduce the difference in heat dissipation characteristics of the plurality of semiconductor laser elements 10 to 12. This makes it possible to reduce the difference in characteristics such as the wavelengths of the laser beams L0A to L2A from the plurality of semiconductor laser elements 10 to 12.

[0141] Fifth Embodiment A semiconductor laser device according to a fifth embodiment will be described. The semiconductor laser device according to this embodiment differs from the semiconductor laser device 401 according to the fourth embodiment mainly in that the laser installation surface is parallel to the bottom surface. The semiconductor laser device according to this embodiment will be described below with reference to FIGS. 20 to 22, focusing on the differences from the semiconductor laser device 401 according to the fourth embodiment. FIGS. 20, 21, and 22 are a perspective view, a plan view, and a side view, respectively, showing the configuration of the semiconductor laser device 501 according to this embodiment.

[0142] 20 , a semiconductor laser device 501 includes a housing 2, a plurality of semiconductor laser elements 10 to 15, a plurality of reflecting mirrors 70 to 75, a condenser lens 90, and a plurality of element mounting surfaces 80 to 85. In this embodiment, the semiconductor laser device 501 further includes submounts 20 to 25, fast-axis collimator lenses 30 to 35, a front-stage prism 550, prisms 41 to 45, slow-axis collimator lenses 60 to 65, an optical fiber 4, a laser base 7, current introduction terminals 9 a, 9 b, and a wiring member 9 c.

[0143] In this embodiment, the semiconductor laser device 501 includes a multi-stage base 508 having a plurality of element mounting surfaces 80 to 85 .

[0144] The multi-step base 508 has a lower surface 508ba and is placed on the bottom surface 6a so that the lower surface 508ba is parallel to the bottom surface 6a. The multi-step base 508 has a plurality of stair-like steps. Each of the plurality of steps of the multi-step base 508 has a surface parallel to the lower surface 508ba, and the surfaces parallel to the lower surface 508ba correspond to each of the plurality of element mounting surfaces 80 to 85. Therefore, each of the plurality of element mounting surfaces 80 to 85 is parallel to the bottom surface 6a. Furthermore, each of the plurality of element mounting surfaces 80 to 85 is parallel to one another and is not on the same plane.

[0145] The laser base 7 is a base on which the plurality of semiconductor laser elements 10 to 15 are mounted. In this embodiment, the laser base 7 is a rectangular plate-shaped member having a flat laser mounting surface 7a. The plurality of semiconductor laser elements 10 to 15 are mounted on the laser mounting surface 7a. The laser base 7 is made of, for example, the same material as the bottom 6 of the housing 2.

[0146] In this embodiment, current is supplied to the multiple semiconductor laser elements 10-15 from outside the housing 2 via current introduction terminals 9a, 9b and wiring member 9c. The wiring member 9c is a conductive member disposed within the housing 2 and constitutes part of a current path between the current introduction terminals 9a, 9b and the multiple semiconductor laser elements 10-15. The wiring member 9c extends from near the current introduction terminal 9a to near the semiconductor laser element 10. The multiple semiconductor laser elements 10-15 are connected in series using metal wires W. The current introduction terminal 9a is connected to the wiring member 9c via the metal wire W, and the wiring member 9c is connected to the semiconductor laser element 10 via the metal wire W. More specifically, one electrode of the semiconductor laser element 10 is connected to an electrode on the submount 20 via a conductive bonding material such as Au or AuSn, and the electrode on the submount 20 is connected to the wiring member 9c via the metal wire W. Furthermore, the other electrode of the semiconductor laser element 10 is connected to the semiconductor laser element 11 by a metal wire W. More specifically, one electrode of the semiconductor laser element 11 is connected to an electrode on the submount 21, and the electrode on the submount 21 is connected to the other electrode of the semiconductor laser element 10 by a metal wire W. The semiconductor laser elements 11 to 15 are connected to each other in the same manner as the semiconductor laser element 10 and the semiconductor laser element 11. The semiconductor laser element 15 is connected to the current introduction terminal 9b by a metal wire W. As described above, by using the wiring member 9c extending from near the current introduction terminal 9a to near the semiconductor laser element 10, the length of the metal wire W can be shortened and interference between multiple metal wires W can be suppressed.

[0147] The multiple fast axis collimator lenses 30 to 35 collimate the multiple laser beams L0A to L5A emitted from the multiple semiconductor laser elements 10 to 15, respectively, in the fast axis direction, and emit multiple laser beams L0B to L5B collimated in the fast axis direction.

[0148] The front-stage prism 550 is a prism that deflects the multiple laser beams L1B to L5B emitted from the multiple fast-axis collimator lenses 31 to 35, respectively, and causes them to enter the multiple prisms 41 to 45. The front-stage prism 550 is disposed between the semiconductor laser elements 11 to 15 and the reflecting mirrors 71 to 75, and is a deflection element that imparts a height component from the bottom surface 6a to the propagation direction of the laser beams L1B to L5B (i.e., deflects the laser beams in the height direction). In this embodiment, the front-stage prism 550 is disposed between the multiple fast-axis collimator lenses 31 to 35 and the multiple prisms 41 to 45, and deflects the laser beams L1B to L5B upward (i.e., in the positive direction in the X-axis direction) and emits the laser beams L1G to L5G. The front-stage prism 550 deflects the laser beams L1B to L5B at the same angle. In this embodiment, the laser beam L0B does not enter the pre-stage prism 550. In other words, the pre-stage prism 550 is not disposed on the optical path of the laser beam L0B. Therefore, the laser beam L0B propagates parallel to the bottom surface 6 a from the fast-axis collimator lens 30 to the reflecting mirror 70 (and the condenser lens 90) without being given a component in the height direction.

[0149] The laser beams L0A to L5A and L0B to L5B propagate parallel to the bottom surface 6a in the positive direction of the Z axis between the semiconductor laser elements 10 to 15 and the front-stage prism 550. Furthermore, the laser beams L0A to L5A and L0B to L5B propagate parallel to each other between the semiconductor laser elements 10 to 15 and the front-stage prism 550.

[0150] In this embodiment, the semiconductor laser device 501 includes a single pre-stage prism 550, but may include a plurality of pre-stage prisms 550. For example, the semiconductor laser device 501 may include five pre-stage prisms that impart height direction components to each of the laser beams L1B to L5B.

[0151] The plurality of prisms 41 to 45 deflect the plurality of laser beams L1G to L5G in the fast axis direction (the fast axis direction of the laser beam immediately after being emitted from each semiconductor laser element), respectively, and emit the plurality of laser beams L0C to L2C.

[0152] The plurality of slow-axis collimator lenses 60 to 65 collimate the plurality of laser beams L0B, L1C to L5C in the slow-axis direction, respectively, and emit the plurality of collimated laser beams L0D to L5D.

[0153] The plurality of reflecting mirrors 70 to 75 reflect the plurality of laser beams L0D to L5D, respectively, and emit the plurality of laser beams L0E to L5E.

[0154] The distance in the Z-axis direction from each prism to each semiconductor laser element increases as the height from the bottom surface 6a of the installation position of each prism increases. This allows the distance from the front-stage prism 550 to each prism to vary depending on the height from the bottom surface 6a of the installation position of each prism. The prisms 41 to 45 are installed near the ends of the element installation surfaces 81 to 85 that are closer to the semiconductor laser elements 11 to 15. In other words, the distance in the Z-axis direction from the end of each element installation surface located between each semiconductor laser element and each prism to each prism is shorter than the distance in the Z-axis direction from that end to each semiconductor laser element. This reduces the blocking of each laser beam by the multi-stage base 508.

[0155] The distance from the end of each element mounting surface closest to each semiconductor laser element to each semiconductor laser element increases as the height of each element mounting surface from the bottom surface 6a increases. Furthermore, as the height of each element mounting surface from the bottom surface 6a increases, the length of each element mounting surface in the propagation direction (Z-axis direction) of the laser beams L0D to L5D decreases. In other words, the higher the mirror mounting surface from the bottom surface 6a among the element mounting surfaces 80 to 85, the shorter its length in the propagation direction (Z-axis direction) of the laser beams L0D to L5D.

[0156] The height from the bottom surface 6a of the region of the multistage base 508 between the plurality of element mounting surfaces 80-85 and the plurality of semiconductor laser elements 10-15 is lower than the height of the bottom surface 6a of the light-emitting points of the semiconductor laser elements 10-15. This reduces the possibility of the multistage base 508 blocking each laser beam. In this embodiment, the positions of the ends of the multistage base 508 close to each semiconductor laser element coincide with the ends of the plurality of element mounting surfaces 80-85. In other words, there is no component of the multistage base 508 located between each element mounting surface and the laser base 7. This reduces the possibility of the multistage base 508 blocking each laser beam, and also reduces the weight of the multistage base 508.

[0157] Furthermore, at the end of each element mounting surface, an end face perpendicular to the bottom surface 6a is formed on the multi-stage base 8. The distance in the Z-axis direction from the end face to each semiconductor laser element increases as the height of each element mounting surface from the bottom surface 6a increases. This reduces the blocking of laser light by the multi-stage base 508 between the front-stage prism 550 and the prisms 41 to 45, as shown in FIG.

[0158] The distance in the Z-axis direction from each slow-axis collimator lens to each semiconductor laser element becomes smaller as the height of each slow-axis collimator lens from the bottom surface 6 a increases, which makes it possible to make the optical path lengths from each slow-axis collimator lens to each semiconductor laser element uniform.

[0159] The heights of the reflecting mirrors 70 to 75 from the bottom surface 6a at their installation positions are different from one another. The reflecting mirrors 70, 71, 72, 73, 74, and 75 are higher in this order from the bottom surface 6a at their installation positions.

[0160] For example, when the light-emitting point 11e of the semiconductor laser element 11 is used as a reference, the distance in the first direction (the X-axis direction in this embodiment) from the light-emitting point 11e of the semiconductor laser element 11 to the optical axis of the laser light L1D incident on the reflecting mirror 71 is different from the distance in the first direction from the light-emitting point 11e of the semiconductor laser element 11 to the optical axis of the laser light L2D incident on the reflecting mirror 72. Similarly, the distances in the first direction (the X-axis direction in this embodiment) from the light-emitting point 11e of the semiconductor laser element 11 to the optical axes of the laser light L1D to L5D incident on the reflecting mirrors 71 to 75, respectively, are different from each other.

[0161] The laser beams L1C to L5C and L1D to L5D propagate between the prisms 41 to 45 and the reflecting mirrors 71 to 75 in the positive direction of the Z axis, parallel to the bottom surface 6a, and parallel to the element mounting surfaces 81 to 85. The laser beams L1C to L5C also propagate parallel to one another.

[0162] The laser beams L0E to L5E propagate between the reflecting mirrors 70 to 75 and the condenser lens 90 in the negative direction of the Y axis, parallel to the bottom surface 6a.

[0163] According to the semiconductor laser device 501 of this embodiment, the plurality of semiconductor laser elements 10 to 15 can be mounted on the same plane parallel to the bottom surface 6a, which makes it even easier to mount the plurality of semiconductor laser elements 10 to 15. Furthermore, since it is possible to reduce the distance between the plurality of semiconductor laser elements 10 to 15 and the bottom surface 6a, when a heat sink or the like is connected to the bottom 6 for heat dissipation, the distance from the plurality of semiconductor laser elements 10 to 15 to the heat sink can be reduced. Therefore, the heat dissipation characteristics of the plurality of semiconductor laser elements 10 to 15 can be improved.

[0164] Sixth Embodiment A semiconductor laser device according to the sixth embodiment will be described. The semiconductor laser device according to the sixth embodiment differs from the semiconductor laser device 501 according to the fifth embodiment mainly in that a plurality of semiconductor laser elements are arranged in an airtight package. The semiconductor laser device according to the sixth embodiment will be described below with reference to FIG. 23, focusing on the differences from the semiconductor laser device 501 according to the fifth embodiment. FIG. 23 is a perspective view showing the configuration of the semiconductor laser device 601 according to the sixth embodiment.

[0165] 23 , the semiconductor laser device 601 includes a housing 2, a plurality of semiconductor laser elements 10-12, a plurality of submounts 20-22, a plurality of fast-axis collimator lenses 30-32, a front-stage prism 550, a plurality of prisms 41, 42, a plurality of slow-axis collimator lenses 60-62, a plurality of reflecting mirrors 70-72, a plurality of element mounting surfaces 80-82, an optical fiber 4, and current input terminals 9a, 9b. In this embodiment, the semiconductor laser device 601 further includes an airtight package P06. The semiconductor laser device 601 also includes a multi-stage base 508 having a plurality of element mounting surfaces 80-82.

[0166] The hermetic package P06 is a package that hermetically seals at least one of the plurality of semiconductor laser elements 10-12. In this embodiment, the hermetic package P06 is a single package that hermetically seals the plurality of semiconductor laser elements 10-12 and the plurality of fast-axis collimator lenses 30-32. The submounts 20-22 are also hermetically sealed within the hermetic package P06. The hermetic package P06 has a light-transmitting window P17 for emitting the laser beams L0A-L2A from the plurality of semiconductor laser elements 10-12 to the outside of the hermetic package P06.

[0167] As described above, the semiconductor laser device 601 according to this embodiment includes the hermetic package P06 that hermetically seals at least one of the plurality of semiconductor laser elements 10 to 12.

[0168] As a result, for example, when the plurality of semiconductor laser elements 10 to 12 include an AlGaInN-based semiconductor and emit laser light of wavelengths corresponding to blue light to ultraviolet light, it is possible to suppress deterioration of each semiconductor laser element due to, for example, organic matter adhering to the light-emitting point of each semiconductor laser element due to a photochemical reaction.

[0169] Furthermore, the semiconductor laser device 601 according to this embodiment includes a single hermetic package P06 that hermetically seals the semiconductor laser elements 10 to 12. This simplifies the configuration compared to when the multiple semiconductor laser elements 10 to 12 are individually hermetically sealed. Furthermore, the hermetic package P06 can be attached to the housing 2 more easily than when multiple hermetic packages are used.

[0170] (Other Embodiments) While the semiconductor laser device according to the present disclosure has been described above based on the embodiments and modifications thereof, the present disclosure is not limited to these embodiments and modifications thereof. As long as they do not deviate from the gist of the present disclosure, various modifications conceivable by a person skilled in the art to the embodiments and other forms constructed by combining some of the components of the embodiments and modifications thereof are also included in the scope of the present disclosure.

[0171] For example, the number of semiconductor laser elements according to each embodiment is not particularly limited as long as it is plural. The number of other elements such as fast-axis collimator lenses may also be set appropriately depending on the number of semiconductor laser elements.

[0172] The direction of each laser beam in each embodiment is not limited to the direction of each laser beam in the above-described embodiments. For example, each laser beam emitted from each reflecting mirror does not have to be parallel to the Y-axis direction. Furthermore, the deflection angle of each of the multiple reflecting mirrors does not have to be 90 degrees.

[0173] The airtight package of the semiconductor laser device 301 according to the third embodiment may also be applied to the first, second, fourth, and fifth embodiments. In the fourth and fifth embodiments, a plurality of semiconductor laser elements, a plurality of submounts, and a plurality of fast-axis collimator lenses may be arranged in a single airtight package. In this case, the plurality of semiconductor laser elements may be integrated (i.e., laser arrayed), the plurality of submounts may be integrated, or the plurality of fast-axis collimator lenses may be integrated.

[0174] The rear prism of the semiconductor laser device according to the third modification of the first embodiment may be applied to the semiconductor laser devices according to the other embodiments and their modifications.

[0175] Furthermore, the above-described embodiments can be modified, substituted, added, omitted, and the like in various ways within the scope of the claims or their equivalents.

[0176] The semiconductor laser device according to the present disclosure is particularly useful as a high-brightness, high-power laser light source, such as a laser light source for processing, a laser light source for displays, or a laser light source for medical use.

[0177] DESCRIPTION OF SYMBOLS 1, 201, 201a, 301, 401, 501, 601 Semiconductor laser device 2 Housing 3 Side wall 4 Optical fiber 6 Bottom 6a Bottom surface 7 Laser base 7a, 80a, 81a, 82a, 83a, 84a, 85a, 180a, 181a, 407a Laser installation surface 8, 8a, 108, 308, 408, 508 Multi-stage base 8ba, 408ba, 508ba Bottom surface 9a, 9b Current input terminal 9c Wiring member 10, 11, 12, 13, 14, 15 Semiconductor laser element 10e, 11e, 12e, 13e, 14e, 15e Light-emitting point 20, 21, 22, 23, 24, 25 Submount 30, 31, 32, 33, 34, 35 FAST axis collimator lens 40, 41, 42, 43, 44, 45 Prism 50, 51 Rear stage prism 40a, 40b Side 60, 61, 62, 63, 64, 65 SLOW axis collimator lens 70, 71, 72, 73, 74, 75 Reflecting mirror 80, 81, 82, 83, 84, 85 Element mounting surface 80d Prism mounting surface 80p, 81p Protrusion 80s, 81s Side surface 90 Condenser lens 550 Front stage prism B0 Bonding material L0A, L0B, L0C, L0C2, L0D, L0E, L1A, L1B, L1C, L1C2, L1D, L1E, L2A, L2B, L2C, L2D, L2E, L3A, L3B, L3C, L3D, L3E, L4A, L4B, L4C, L4D, L4E, L5A, L5B, L5C, L5D, L5E, L1G, L2G, L3G, L4G, L5G Laser light P02 Lid P06, P10, P11 Hermetic package P17 Light-transmitting window P21 First package P31 Anode lead-out electrode P34 Cathode lead-out electrode W Metal wire

Claims

1. A housing having a flat bottom surface; A plurality of semiconductor laser elements disposed within the housing; a plurality of fast axis collimator lenses that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements in a fast axis direction; a plurality of prisms each deflecting the plurality of laser beams in the FAST axis direction; a plurality of slow axis collimator lenses that collimate the plurality of laser beams in a slow axis direction, each of the plurality of prisms is disposed between each of the plurality of fast-axis collimator lenses and each of the plurality of slow-axis collimator lenses; the plurality of laser beams respectively outputted from the plurality of slow axis collimator lenses have different optical axis positions in the fast axis direction, the plurality of semiconductor laser elements includes a first semiconductor laser element that emits a first laser light, the plurality of FAST axis collimator lenses include a first FAST axis collimator lens that collimates the first laser beam in the FAST axis direction, the plurality of prisms includes a first prism that deflects the first laser light, a central axis of the first FAST axis collimator lens is shifted from an optical axis of the first laser beam in a first direction along the FAST axis direction, The first prism deflects the first laser light in a direction opposite to the first direction. Semiconductor laser device.

2. A semiconductor laser device, comprising: A housing having a flat bottom surface; A plurality of semiconductor laser elements disposed within the housing; a plurality of fast axis collimator lenses that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements in a fast axis direction; a plurality of prisms each deflecting the plurality of laser beams in the FAST axis direction; a plurality of slow axis collimator lenses that collimate the plurality of laser beams in a slow axis direction, each of the plurality of prisms is disposed between each of the plurality of fast-axis collimator lenses and each of the plurality of slow-axis collimator lenses; the plurality of laser beams respectively outputted from the plurality of slow axis collimator lenses have different optical axis positions in the fast axis direction, the semiconductor laser device further includes a plurality of rear-stage prisms that deflect the plurality of laser beams emitted from the plurality of prisms in the FAST axis direction, the plurality of semiconductor laser elements includes a first semiconductor laser element that emits a first laser light, the plurality of prisms includes a first prism that deflects the first laser light, the plurality of rear-stage prisms includes a first rear-stage prism that deflects the first laser light, The direction of deflection of the first laser light by the first rear prism is opposite to the direction of deflection of the first laser light by the first prism. Semiconductor laser device.

3. A housing having a flat bottom surface; A plurality of semiconductor laser elements disposed within the housing; a plurality of fast axis collimator lenses that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements in a fast axis direction; a plurality of prisms each deflecting the plurality of laser beams in the FAST axis direction; a plurality of slow axis collimator lenses that collimate the plurality of laser beams in a slow axis direction, each of the plurality of prisms is disposed between each of the plurality of fast-axis collimator lenses and each of the plurality of slow-axis collimator lenses; the plurality of laser beams respectively outputted from the plurality of slow axis collimator lenses have different optical axis positions in the fast axis direction, A prism mounting surface on which each of the plurality of prisms is mounted or a bottom surface of each of the plurality of prisms has a curved shape. Semiconductor laser device.

4. A semiconductor laser device, comprising: A housing having a flat bottom surface; A plurality of semiconductor laser elements disposed within the housing; a plurality of fast axis collimator lenses that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements in a fast axis direction; a plurality of prisms each deflecting the plurality of laser beams in the FAST axis direction; a plurality of slow axis collimator lenses that collimate the plurality of laser beams in a slow axis direction, each of the plurality of prisms is disposed between each of the plurality of fast-axis collimator lenses and each of the plurality of slow-axis collimator lenses; the plurality of laser beams respectively outputted from the plurality of slow axis collimator lenses have different optical axis positions in the fast axis direction, The semiconductor laser device further comprises a multi-step base having a plurality of steps, each of the plurality of steps has an element mounting surface parallel to the bottom surface and a side surface extending from the element mounting surface; Each of the plurality of prisms is disposed on the side surface. Semiconductor laser device.

5. A housing having a flat bottom surface; A plurality of semiconductor laser elements disposed within the housing; a plurality of fast axis collimator lenses that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements in a fast axis direction; a plurality of prisms each deflecting the plurality of laser beams in the FAST axis direction; a plurality of slow axis collimator lenses that collimate the plurality of laser beams in a slow axis direction, each of the plurality of prisms is disposed between each of the plurality of fast-axis collimator lenses and each of the plurality of slow-axis collimator lenses; the plurality of laser beams respectively outputted from the plurality of slow axis collimator lenses have different optical axis positions in the fast axis direction, each of the plurality of prisms deflects the plurality of laser beams in the same direction; The installation angle of each of the plurality of prisms is adjustable. Semiconductor laser device.

6. A housing having a flat bottom surface; A plurality of semiconductor laser elements disposed within the housing; a plurality of fast axis collimator lenses that collimate the plurality of laser beams emitted from the plurality of semiconductor laser elements in a fast axis direction; a plurality of prisms each deflecting the plurality of laser beams in the FAST axis direction; a plurality of slow axis collimator lenses that collimate the plurality of laser beams in a slow axis direction, each of the plurality of prisms is disposed between each of the plurality of fast-axis collimator lenses and each of the plurality of slow-axis collimator lenses; the plurality of laser beams respectively outputted from the plurality of slow axis collimator lenses have different optical axis positions in the fast axis direction, The plurality of semiconductor laser elements are disposed on the same plane, The distances of the plurality of prisms from the corresponding semiconductor laser elements among the plurality of semiconductor laser elements are different from each other. Semiconductor laser device.

7. the plurality of semiconductor laser elements includes a first semiconductor laser element that emits a first laser light, the plurality of FAST axis collimator lenses include a first FAST axis collimator lens that collimates the first laser beam in the FAST axis direction, the plurality of prisms includes a first prism that deflects the first laser light, a central axis of the first FAST axis collimator lens is shifted from an optical axis of the first laser beam in a first direction along the FAST axis direction, The first prism deflects the first laser light in a direction opposite to the first direction.

7. The semiconductor laser device according to claim 2,

8. a plurality of reflecting mirrors that reflect the plurality of laser beams respectively emitted from the plurality of slow axis collimator lenses; 7. The semiconductor laser device according to claim 1,

9. The propagation direction of the laser light emitted from each of the semiconductor laser elements has a component in a height direction from the bottom surface.

7. The semiconductor laser device according to claim 1,

10. The plurality of prisms each deflect the plurality of laser beams in the same direction.

7. The semiconductor laser device according to claim 1, wherein the first and second electrodes are arranged parallel to each other.

11. a plurality of rear-stage prisms that deflect the plurality of laser beams emitted from the plurality of prisms in the FAST axis direction, respectively; 7. The semiconductor laser device according to claim 1,

12. the plurality of semiconductor laser elements includes a first semiconductor laser element that emits a first laser light, the plurality of prisms includes a first prism that deflects the first laser light, the plurality of rear-stage prisms includes a first rear-stage prism that deflects the first laser light, The direction of deflection of the first laser light by the first rear prism is opposite to the direction of deflection of the first laser light by the first prism.

12. The semiconductor laser device according to claim 11.

13. A prism mounting surface on which each of the plurality of prisms is mounted or a bottom surface of each of the plurality of prisms has a curved shape.

7. The semiconductor laser device according to claim 1, 2, 5 or 6.

14. The curved surface is concave.

14. The semiconductor laser device according to claim 13.

15. A multi-stage base having a plurality of stages is provided, each of the plurality of steps has an element mounting surface parallel to the bottom surface and a side surface extending from the element mounting surface; Each of the plurality of prisms is disposed on the side surface.

7. The semiconductor laser device according to claim 1, 2, 5 or 6.

16. The slow axis of each of the plurality of laser beams incident on each of the plurality of prisms is perpendicular to the side surface on which each of the plurality of prisms is disposed.

16. The semiconductor laser device according to claim 15.

17. each of the plurality of steps has a protrusion protruding from the element mounting surface and facing the side surface; Each of the plurality of prisms is disposed on the side surface and the protrusion.

16. The semiconductor laser device according to claim 15.

18. One or more airtight packages; each of the one or more airtight packages hermetically seals one or more semiconductor laser elements among the plurality of semiconductor laser elements and one or more FAST-axis collimator lenses among the plurality of FAST-axis collimator lenses, into which one or more laser beams emitted from the one or more semiconductor laser elements are respectively incident; each of the one or more semiconductor laser elements and each of the one or more fast axis collimator lenses are fixed with an inorganic adhesive; each of the one or more hermetic packages has a light-transmitting window; One or more laser beams emitted from the one or more semiconductor laser elements are transmitted through the light-transmitting window.

7. The semiconductor laser device according to claim 1,

19. The plurality of semiconductor laser elements are disposed on the same plane.

6. The semiconductor laser device according to claim 1,

20. The laser beams emitted from the first axis collimator lenses are deflected and made incident on the first prisms.

7. The semiconductor laser device according to claim 1,

21. The housing hermetically seals the internal space.

7. The semiconductor laser device according to claim 1,