Laser light source

Abstract

To provide a laser light source in which positional deviation between a laser diode chip and a lens is less likely to occur.SOLUTION: A laser light source includes: an end-face emission type laser diode chip that has a semiconductor multilayer structure including a light emitting layer, a first end face for emitting laser light generated in the light emitting layer, and a second end face opposite thereto, and in which a resonator length is defined by a distance from the first end face to the second end face; a submount that has a principal plane to which the laser diode chip is fixed, and a pair of lens support units located on both sides of the first end face of the laser diode chip across the principal plane; a lens that is joined to end faces of the pair of lens support units; and a semiconductor laser package that houses the laser diode chip, the lens, and the submount. The first end face of the laser diode chip protrudes in a resonator length direction beyond an edge of the principal plane, and the end faces of the pair of lens support units protrudes in the resonator length direction beyond the first end face of the laser diode chip.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present disclosure relates to a laser light source.

Background Art

[0002] Laser light sources are used in various applications such as processing, projectors, and lighting fixtures. A typical example of such a laser light source includes a laser diode chip, a submount that supports the laser diode chip, and a collimating lens that reduces the divergence angle of the laser light emitted from the laser diode chip (for example, Patent Document 1). When lenses such as a laser diode chip, a submount, and a collimating lens are housed in a semiconductor laser package, it becomes possible to collimate the laser light with a small lens before the laser light diverges greatly. On the other hand, due to a slight misalignment between the laser diode chip and the lens, the direction of the optical axis of the laser light emitted from the laser light source to the outside may be greatly misaligned.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need for a laser light source in which misalignment between a laser diode chip and a lens is less likely to occur.

Means for Solving the Problems

[0005] In one embodiment, the laser light source of the present disclosure includes a semiconductor stacked structure including a light emitting layer, a substrate that supports the semiconductor stacked structure, a first end face that emits laser light generated in the light emitting layer, and a second end face on the side opposite to the first end face. The resonator length is defined by the distance from the first end face to the second end face. An end-face emission type laser diode chip, a main plane to which the laser diode chip is fixed, a pair of lens support portions located on both sides of the first end face of the laser diode chip, and a back face located on the side opposite to the main plane. A submount having, a lens joined to end faces of the pair of lens support portions, and a semiconductor laser package that houses the laser diode chip, the lens, and the submount. The laser diode chip is fixed to the submount in a state where the light emitting layer is closer to the submount than the substrate of the laser diode chip. The first end face of the laser diode chip protrudes in the direction of the resonator length from an edge of the main plane, and the end faces of the pair of lens support portions protrude in the direction of the resonator length from the first end face of the laser diode chip.

Advantages of the Invention

[0006] According to the present disclosure, it is possible to realize a laser light source in which misalignment between the laser diode chip and the lens is less likely to occur.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] Hereinafter, with reference to the drawings, the laser light source in the embodiments of the present disclosure will be described in detail. Parts denoted by the same reference numerals in the plurality of drawings indicate the same or equivalent parts.

[0009] Furthermore, the following is an exemplification for embodying the technical idea of the present disclosure and does not limit the present disclosure thereto. Also, descriptions of dimensions, materials, shapes, relative arrangements, etc. of components are not intended to limit the scope of the present disclosure thereto alone but are intended to be illustrative. The sizes and positional relationships of members shown in each drawing may be exaggerated for ease of understanding.

[0010] (Embodiment 1) First, with reference to FIGS. 1A and 1B, and FIGS. 2A to 2C, a basic configuration example of the laser light source in Embodiment 1 of the present disclosure will be described.

[0011] FIG. 1A is a perspective view schematically showing a configuration example of a laser light source 100 in Embodiment 1 of the present disclosure. FIG. 1B is a diagram schematically showing a planar configuration of the laser light source 100 in FIG. 1A. The laser light source 100 in the present embodiment includes a laser diode chip 10, a submount 20 that supports the laser diode chip 10, a collimating lens 30 supported by the submount 20, and a semiconductor laser package 40 that houses these elements or components. Also, the laser light source 100 in the present embodiment includes a pair of lead terminals 50 that penetrate the semiconductor laser package 40 and supply power to the laser diode chip 10. The semiconductor laser package 40 includes a lid body 40L, a base body 40b, and a light-transmitting window 40w. In the laser light source 100 in the present embodiment, laser light emitted from the laser diode chip 10 and collimated by the collimating lens 30 is taken out to the outside through the light-transmitting window 40w.

[0012] In FIG. 1A, for the sake of clarity of explanation, the lid 40L, the base 40b, and the light-transmitting window 40w in the semiconductor laser package 40 are shown in a separated state, but actually they are joined. In FIG. 1B, the description of the lid 40L in the semiconductor laser package 40 is omitted.

[0013] In the drawings, for reference, the X-axis, Y-axis, and Z-axis orthogonal to each other are schematically shown. For the sake of clarity of explanation, in the present disclosure, the side where the laser diode chip 10, the submount 20, and the collimating lens 30 are located within the base 40b may be expressed as "up". This does not limit the orientation when the laser light source 100 is used, and the orientation of the laser light source 100 is arbitrary.

[0014] FIG. 2A is a perspective view showing more details of a configuration in which the semiconductor laser package 40 and a pair of lead terminals 50 are omitted from the laser light source 100 of FIG. 1A. The region surrounded by the broken line in FIG. 2A represents an example of the detailed structure of the laser diode chip 10 arranged on the submount 20. In FIG. 2A, the submount 20 and the collimating lens 30 are shown in a separated state, but actually they are joined. FIG. 2B is a top view schematically showing the laser light source 100 of FIG. 2A. FIG. 2C is a cross-sectional view taken along the line IIC-IIC parallel to the YZ plane of the configuration of FIG. 2B. In the present disclosure, with reference to the submount 20, the side where the collimating lens 30 is located may be expressed as "front".

[0015] As shown in FIG. 2A, the laser diode chip 10 is an end-face emission type laser diode chip, and includes a semiconductor laminate structure 10a including a first cladding layer 10C1, a second cladding layer 10C2, and an emission layer 10L, and a substrate 10b that supports the semiconductor laminate structure 10a. It has an output end face 10e1 that emits high-power laser light generated in the light-emitting layer 10L, and a rear end face 10e2 on the side opposite to the output end face 10e1. The light-emitting layer 10L is located between a first cladding layer 10C1 and a second cladding layer 10C2. The laser diode chip 10 may include other layers such as a buffer layer and a contact layer. In the present disclosure, the "output end face 10e1" may be referred to as the "first end face 10e1", and the "rear end face 10e2" may be referred to as the "second end face 10e2".

[0016] The laser diode chip 10 is fixed to the submount 20 in a face-down state where the light-emitting layer 10L is closer to the submount 20 than the substrate 10b. The total size of the semiconductor laminate 10a and the substrate 10b in the Y direction in the laser diode chip 10 is about 80 μm. The total size of the substrate 10b and the first cladding layer 10C1 in the Y direction is larger than the size of the second cladding layer 10C2 in the Y direction. In the face-down state, the distance between the light-emitting layer 10L and the submount 20 is about one-tenth compared to the face-up state where the light-emitting layer 10L is farther from the submount 20 than the substrate 10b. Therefore, in the face-down state, even if high-power laser light is emitted from the light-emitting layer 10L, the heat generated in the light-emitting layer 10L can be efficiently transferred to the submount 20. The output of the laser light in the present embodiment is, for example, 3 W or more and 50 W or less.

[0017] The semiconductor laminate structure 10a may have, for example, a double hetero structure that forms the energy levels of a quantum well. The bandgap of the light-emitting layer 10L is smaller than the bandgaps of the first cladding layer 10C1 and the second cladding layer 10C2. In the present embodiment, the substrate 10b and the first cladding layer 10C1 on the substrate 10b may each be formed of an n-type semiconductor. The light-emitting layer 10L may be formed of an intrinsic semiconductor, an n-type semiconductor, or a p-type semiconductor, and the second cladding layer 10C2 on the light-emitting layer 10L may be formed of a p-type semiconductor. The n-type and p-type may be reversed. By injecting current from the p-type cladding layer to the n-type cladding layer, an inverted distribution of carriers occurs in the light-emitting layer 10L, and light is induced and emitted from the light-emitting layer 10L. The refractive index of the light-emitting layer 10L is designed to be higher than the refractive indices of the first cladding layer 10C1 and the second cladding layer 10C2, and the light generated in the light-emitting layer 10L is confined within the light-emitting layer 10L by total reflection. The light-emitting layer 10L functions as a resonator, and laser light is emitted from the emission end face 10e1 of the light-emitting layer 10L. The resonator length of the light-emitting layer 10L is defined by the distance from the emission end face 10e1 to the rear end face 10e2. The direction of the resonator length is parallel to the Z direction. The resonator length is, for example, 500 μm or more and 5000 μm or less. When the resonator length is long, the contact area between the laser diode chip 10 and the submount 20 can be widened, so that the heat generated in the light-emitting layer 10L can be efficiently transmitted to the submount 20.

[0018] The laser light emitted from the emission end face 10e1 of the laser diode chip 10 diverges rapidly in the YZ plane and slowly in the XZ plane as it propagates. The spot of the laser light, when not collimated, has an elliptical shape in the far field with the Y direction as the major axis and the X direction as the minor axis in the XY plane.

[0019] The laser diode chip 10 can emit purple, blue, green, or red laser light in the visible region, or infrared or ultraviolet laser light. The emission peak wavelength of the purple light is desirably in the range of 350 nm or more and 419 nm or less, and more desirably in the range of 400 nm or more and 415 nm or less. The emission peak wavelength of the blue light is desirably in the range of 420 nm or more and 494 nm or less, and more desirably in the range of 440 nm or more and 475 nm or less. Examples of the semiconductor laser element that emits purple or blue laser light include a semiconductor laser element containing a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, and AlGaN can be used. The emission peak wavelength of the green light is desirably in the range of 495 nm or more and 570 nm or less, and more desirably in the range of 510 nm or more and 550 nm or less. Examples of the semiconductor laser element that emits green laser light include a semiconductor laser element containing a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, and AlGaN can be used. The emission peak wavelength of the red light is desirably in the range of 605 nm or more and 750 nm or less, and more desirably in the range of 610 nm or more and 700 nm or less. Examples of the semiconductor laser element that emits red laser light include a semiconductor laser element containing a semiconductor such as InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductors. As the semiconductor laser element for red light, a semiconductor laser element having two or more waveguide regions can be used. The semiconductor laser element containing these semiconductors is more likely to have its output decreased by heat compared to the semiconductor laser element containing a nitride semiconductor. By increasing the waveguide regions, heat can be dispersed to reduce the output decrease of the semiconductor laser element.

[0020] The submount 20 has a main plane 20s1 to which the laser diode chip 10 is fixed, a pair of lens support portions 20LS located on both sides of the emission end face 10e1 of the laser diode chip 10, a back face 20s2 located on the side opposite to the main plane 20s1, and a front end face 20fe connecting the main plane 20s1 and the back face 20s2. The main plane 20s1 and the front end face 20fe define an edge 20ed of the main plane 20s1. In the example shown in FIG. 2A, the pair of lens support portions 20LS are a pair of convex portions located on both sides of the laser diode chip 10 and extending in the Z direction. The submount 20 has the following U-shaped configuration extending in the Z direction behind the front end face 20fe. This U-shaped configuration is formed by dividing a rectangular tube body extending in the Z direction and mirror-symmetric with respect to a plane parallel to the YZ plane by a plane parallel to the XZ plane. The end faces 20se of the pair of lens support portions 20LS protrude more in the resonator length direction than the emission end face 10e1 of the laser diode chip 10. The normal direction of the main plane 20s1 is parallel to the Y direction.

[0021] The distance in the Z direction between the end faces 20se of the pair of lens support portions 20LS and the emission end face 10e1 of the laser diode chip 10 can be designed to be approximately equal to the focal length of the collimating lens 30. The distance in the Z direction between the end faces 20se of the pair of lens support portions 20LS and the emission end face 10e1 of the laser diode chip 10 is, for example, 50 μm or more and 100 μm or less. The size of the pair of lens support portions 20LS in the Y direction can be approximately the same as the size of the collimating lens 30 in the Y direction. The size of the pair of lens support portions 20LS in the Y direction may be larger than, equal to, or smaller than the size of the collimating lens 30 in the Y direction. The size of the pair of lens support portions 20LS in the Y direction is, for example, 100 μm or more and 500 μm or less.

[0022] The size of the submount 20 in the X direction is, for example, 1 mm or more and 3 mm or less. Among the submount 20, the size of the portion other than the pair of lens support portions 20LS in the Y direction is, for example, 100 μm or more and 500 μm or less, and the size of the portion other than the pair of lens support portions 20LS in the Z direction is, for example, 1 mm or more and 6 mm or less. In the present disclosure, the upper limit of the size can be determined from the viewpoint of miniaturization of the laser light source 100.

[0023] In the submount 20, the emission end face 10e1 of the laser diode chip 10 protrudes in the resonator length direction from the edge 20ed of the main plane 20s1. The distance in the Z direction between the emission end face 10e1 of the laser diode chip 10 and the edge 20ed of the main plane 20s1 is, for example, 2 μm or more and 50 μm or less. With this arrangement, even when the laser diode chip 10 and the main plane 20s1 of the submount 20 are fixed with a bonding material such as an inorganic material like gold-tin in a face-down state, it is possible to suppress the bonding material from rising to the emission end face 10e1 of the light-emitting layer 10L. In the laser light source disclosed in Patent Document 1, when the laser diode chip is arranged in a face-down state, the bonding material for bonding the laser diode chip and the submount may rise to the emission end face of the light-emitting layer in the laser diode chip. As a result, the output of the laser light emitted from the laser diode chip may decrease. In the laser light source 100 of the present embodiment, such a decrease in the output of the laser light can be suppressed. In the laser light source 100 of the present embodiment, such a decrease in the output of the laser light can be suppressed.

[0024] Part or all of the submount 20 can be formed from, for example, a ceramic containing at least one selected from the group consisting of AlN, SiC, and alumina and an alloy such as CuW. The submount 20 can be produced, for example, by sintering ceramic powder. The thermal conductivity of the ceramic can be, for example, 10 [W / m·K] or more and 500 [W / m·K] or less. Also, in order to suppress deformation due to the heat applied during the fixing of the laser diode chip 10, the ceramic can have a low coefficient of thermal expansion. The coefficient of thermal expansion is 2×10 -6[1 / K] or more and 1×10 or less -5 [1 / K] or less. On the main plane 20s1 and the back plane 20s2 of the submount 20, a metal film such as gold plating with a thickness of, for example, 0.5 μm or more and 10 μm or less may be formed. With the metal film formed on the main plane 20s1, the laser diode chip 10 can be bonded to the main plane 20s1 with, for example, gold-tin. With the metal film formed on the back plane 20s2, the submount 20 can be bonded to the bottom 40b1 with, for example, gold-tin.

[0025] The collimating lens 30 is a so-called FAC (Fast Axis Collimator) lens that collimates the component of the laser light emitted from the laser diode chip 10 that diverges significantly in the YZ plane. A so-called SAC (Slow Axis Collimator) lens (not shown) that collimates the component of the laser light that diverges slightly in the XZ plane may be disposed outside the laser light source 100 as necessary. In the present disclosure, "collimate" includes not only making the laser light parallel light but also reducing the divergence angle of the laser light. Note that depending on the application, another lens such as a condenser lens may be used instead of the collimating lens 30.

[0026] The collimating lens 30 is a cylindrical lens having a structure extending in the X direction, having no curvature in the X-axis direction, and having a curvature in the Y direction. The direction in which the collimating lens 30 extends is perpendicular to both the normal direction of the main plane 20s1 of the submount 20 and the resonator length direction. Since the sizes of the collimating lens 30 and the pair of lens support portions 20LS in the Y direction are about the same, it is easy to provide the center of gravity of the collimating lens 30 to be located between the pair of lens support portions 20LS when viewed from the resonator length direction. Due to this positional relationship of the center of gravity of the collimating lens 30, the collimating lens 30 can be stably and accurately provided on the submount 20.

[0027] In the present embodiment, when the back surface 20s2 of the submount 20 is used as a reference, the height of the upper surfaces of the pair of lens support portions 20LS in the Y direction is substantially equal to the height of the upper surface of the collimating lens 30 in the Y direction. The position of the collimating lens 30 with respect to the pair of lens support portions 20LS is roughly adjusted so that the above two heights are substantially equal. Then, while emitting laser light from the laser diode chip 10, the position of the collimating lens 30 with respect to the pair of lens support portions 20LS is finely adjusted so that the laser light is properly collimated. Note that the above two heights do not necessarily have to be substantially equal and may be different.

[0028] Since the collimating lens 30 in the present embodiment is uniform along the X direction, it is not necessary to consider the alignment in the X direction between the emission end surface 10e1 of the laser diode chip 10 and the collimating lens 30. It is only necessary that only the opposing portion of the collimating lens 30 facing the emission end surface 10e1 of the laser diode chip 10 and its peripheral portion be uniform along the X direction. Therefore, the other two side portions do not necessarily have to be uniform along the X direction and do not have to be transparent. The size of the two side portions of the collimating lens 30 in the Y direction may be larger than, equal to, or smaller than the size of the opposing portion and its peripheral portion in the Y direction. The collimating lens 30 can be formed from at least one of, for example, glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic.

[0029] The collimating lens 30 is joined in the Z direction to the end faces 20se of a pair of lens support portions 20LS. Even if there is some variation in the thickness of the bonding material that joins the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS, that variation has almost no effect on the position of the collimating lens 30 in the Y direction. Different from the configuration of the present embodiment, it is also possible to arrange a pedestal having a plane parallel to the main plane 20s1 in front of the submount 20 and provide the collimating lens 30 on the plane of that pedestal. However, in such a configuration, if there is variation in the thickness of the bonding material between the collimating lens 30 and the plane of the pedestal, a positional shift in the Y direction may occur between the laser diode chip 10 and the collimating lens 30, and there is a possibility that the direction of the optical axis of the laser light emitted from the laser light source 100 to the outside will shift significantly. In contrast, in the present embodiment, a positional shift in the Y direction between the laser diode chip 10 and the collimating lens 30 is less likely to occur, and the optical axis of the laser light emitted from the laser light source 100 to the outside can be directed in the designed direction. Even if there is some variation in the thickness of the bonding material, the position of the collimating lens 30 only changes slightly along the optical axis of the laser light, so that variation has almost no effect on the direction of the optical axis of the laser light.

[0030] The collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS can be joined with a bonding material of an inorganic material such as gold-tin. A metal film may be formed in advance on the bonding surface of the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS. These metal films enable bonding with, for example, gold-tin. The bonding temperature of gold-tin is approximately 280°C. If the thermal conductivity of the ceramic forming the submount 20 is low, the influence of the heat during the joining of the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS on the laser diode chip 10 can be reduced.

[0031] As another example, the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS can be joined with a bonding material containing a thermosetting resin. The bonding temperature of the thermosetting resin is about 100° C., which is lower than the bonding temperature of inorganic materials. Therefore, the influence of the heat during the joining of the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS on the laser diode chip 10 can be further reduced. In the joining of the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS, the thermosetting resin can be heated, for example, by irradiating the position of point P shown in FIG. 2A with laser light. The distance in the Z direction between the position of point P and the end faces 20se of the pair of lens support portions 20LS is, for example, 50 μm or more and 500 μm or less. In the present embodiment, in a top view, since the optical axis of the laser light emitted from the laser diode chip 10 and the bonding material do not overlap, even if outgas is generated from the bonding material containing the thermosetting resin, it is possible to suppress the outgas from approaching the laser diode chip 10. As a result, it is possible to suppress the occurrence of dust collection described later at the emission end face 10e1 of the laser diode chip 10.

[0032] Some bonding materials for inorganic materials may contain an organic substance as a binder. Even when using such a bonding material for the joining of the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS, it is possible to suppress the outgas generated by heating from approaching the laser diode chip 10.

[0033] The collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS may be joined by direct bonding without using a bonding material. Examples of direct bonding include diffusion bonding, room temperature bonding, and anodic bonding.

[0034] As is clear from the description of the embodiment using a bonding material, also in the joining by direct bonding, similar to the joining using a bonding material, it is possible to suppress the displacement of the collimating lens 30 in the Y direction.

[0035] In the laser light source 100 according to the present embodiment, the submount 20 supports the laser diode chip 10 and the collimating lens 30. Since the distance between the emission end face 10e1 of the laser diode chip 10 and the collimating lens 30 is short, the divergence of the laser light emitted from the laser diode chip 10 can be reduced by the small collimating lens 30 before the laser light diverges significantly. Therefore, it is possible to realize a small-sized laser light source 100. Also, it is possible to reduce the diameter of the collimated beam that has passed through the collimating lens 30.

[0036] The semiconductor laser package 40 may hermetically seal the laser diode chip 10, the submount 20, and the collimating lens 30. When the laser diode chip 10 emits laser light with a short wavelength, for example, 350 nm or more and 570 nm or less, organic gas components contained in the atmosphere may be decomposed by the laser light, and the decomposition products may adhere to the emission end face 10e1 of the laser diode chip 10. Also, if the emission end face 10e1 of the laser diode chip 10 is in contact with the outside air, there is a possibility that end face deterioration may progress during operation due to dust collection or the like. Such end face deterioration can lead to a decrease in the optical output of the laser diode chip 10. In order to improve the reliability of the laser diode chip 10 and extend its life, it is desirable that the semiconductor laser package 40 hermetically seals the laser diode chip 10. The hermetic sealing by the semiconductor laser package 40 may be performed regardless of the wavelength of the laser light emitted from the laser diode chip 10.

[0037] In the semiconductor laser package 40, the substrate 40b is thermally in contact with the back surface 20s2 of the submount 20. The substrate 40b can be formed of a material having a high thermal conductivity. The material is, for example, a metal containing at least one selected from the group consisting of Cu, Al, Ag, Fe, Ni, Mo, Cu, W, and CuMo. In order to align the heights of the emission end face 10e1 of the laser diode chip 10 and the light-transmitting window 40w, a member 40m having a high thermal conductivity may be provided between the bottom face 40bt of the substrate 40b and the submount 20 as shown in FIG. 1B. The member 40m can be formed of the same material as the portion including the bottom face 40bt of the substrate 40b. Alternatively, at least a part of the bottom face 40bt of the substrate 40b may be raised, and the submount 20 may be disposed on the raised bottom face 40bt. The portion including the bottom face 40bt of the substrate 40b can be formed of, for example, copper. The portion of the substrate 40b surrounding the laser diode 10, the submount 20, and the collimating lens 30 can be formed of, for example, kovar. Kovar is an alloy obtained by adding nickel and cobalt to iron as a main component. The lid 40L in the semiconductor laser package 40 may be formed of the same material as the substrate 40b or may be formed of a different material. The light-transmitting window 40w in the semiconductor laser package 40 is attached to the substrate 40b and transmits the laser light emitted from the laser diode chip 10. The light-transmitting window 40w in the semiconductor laser package 40 can be formed of, for example, at least one of glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic, similar to the collimating lens 30.

[0038] The pair of lead terminals 50 are each electrically connected to the laser diode chip 10 by wires as follows. In the example shown in FIG. 2A, a metal film such as a gold plating is formed on the upper surface of the laser diode chip 10. The metal film and one of the pair of lead terminals 50 are electrically connected by a wire. Similarly, a metal film such as a gold plating is also formed on the main plane 20s1 of the submount 20. The metal film and the other of the pair of lead terminals 50 are electrically connected by a wire. A current is injected from the second cladding layer 10C2 to the first cladding layer 10C1 in the laser diode chip 10 by the pair of lead terminals 50. The pair of lead terminals 50 are electrically connected to an external circuit (not shown) that adjusts the emission timing and output of the laser light emitted from the laser diode chip 10. The pair of lead terminals 50 are formed of a material having good conductivity. Examples of such materials include metals such as Fe-Ni alloys or Cu alloys. A current is injected from the second cladding layer 10C2 to the first cladding layer 10C1 in the laser diode chip 10 by the pair of lead terminals 50. The pair of lead terminals 50 are electrically connected to an external circuit (not shown) that adjusts the emission timing and output of the laser light emitted from the laser diode chip 10. The pair of lead terminals 50 are formed of a material having good conductivity. Examples of such materials include metals such as Fe-Ni alloys or Cu alloys.

[0039] In the laser light source 100 according to the present embodiment, the submount 20 supports the laser diode chip 10 by the main plane 20s1 between the pair of lens support portions 20LS, and supports the collimating lens 30 by the end faces 20se of the pair of lens support portions 20LS. Thereby, as described above, the alignment between the laser diode chip 10 and the collimating lens 30 becomes easy, and it becomes possible to realize a small-sized laser light source 100. Further, in the laser light source 100 according to the present embodiment, even when the laser diode chip 10 is disposed in a face-down state on the submount 20, it is possible to suppress the bonding material from rising to the emission end face 10e1 of the laser diode chip 10.

[0040] (Modification Example 1 of Embodiment 1) Next, Modification Examples 1 to 5 of the laser light source 100 according to Embodiment 1 of the present disclosure will be described. In the following modification examples, the description of the semiconductor laser package 40 and the pair of lead terminals 50 is omitted. Descriptions that overlap with the above may be omitted.

[0041] Referring to FIGS. 3A to 3C, a configuration example of the laser light source 110 in Modification 1 of Embodiment 1 of the present disclosure will be described. FIG. 3A is a perspective view schematically showing a configuration example of the laser light source 110 in Modification 1 of Embodiment 1 of the present disclosure. FIG. 3B is a top view schematically showing the laser light source 110 of FIG. 3A. FIG. 3C is a cross-sectional view taken along line IIIC-IIIC parallel to the YZ plane of the configuration of FIG. 3B. The difference between the laser light source 110 in Modification 1 of Embodiment 1 and the laser light source 100 in Embodiment 1 is the shape of the submount 20. The front end face 20fe of the submount 20 has a central end face 20fe1 and both side end faces 20fe2 located on both sides of the central end face 20fe1. The central end face 20fe1 is recessed in the resonator length direction more than the both side end faces 20fe2. The edge 20ed of the main plane 20s1 in Modification 1 of Embodiment 1 is defined by the main plane 20s1 and the central end face 20fe1. The size of the recess in the Z direction of the central end face 20fe1 is, for example, 5 μm or more and 100 μm or less, the size in the X direction is, for example, 50 μm or more and 200 μm or less, and the size from the main plane 20s1 in the Y direction is, for example, 100 μm or more and 500 μm or less. The recess does not necessarily need to penetrate in the Y direction.

[0042] The emission end face 10e1 of the laser diode chip 10 protrudes in the resonator length direction beyond the edge 20ed of the main plane 20s1 defined by the main plane 20s1 and the central end face 20fe1. The both side end faces 20fe2 in the submount 20 protrude in the resonator length direction beyond the emission end face 10e1 of the laser diode chip 10, similar to the end faces 20se of the pair of lens support portions 20LS. The edge 20ed of the main plane 20s1 defined by the main plane 20s1 and the central end face 20fe1 can suppress the bonding material from rising up to the emission end face 10e1 of the laser diode chip 10. The submount 20 in the modification 1 of the embodiment 1 can be easily manufactured because only a part of the front end face 20fe needs to be removed in the above-described U-shaped configuration extending in the Z direction. Further, since the collimating lens 30 is bonded to an L-shaped end face including the end faces 20se of the pair of lens support portions 20LS and the both side end faces 20fe2, the contact area between the collimating lens 30 and the submount 20 becomes wide, and the bonding can be facilitated.

[0043] Next, with reference to FIGS. 4A to 4C, a configuration example of the laser light source 120 in the modification 2 of the embodiment 1 of the present disclosure will be described. FIG. 4A shows the laser in the modification 2 of the embodiment 1 of the present disclosure FIG. 4A is a perspective view schematically showing a configuration example of the light source 120. FIG. 4B is a top view schematically showing the laser light source 120 of FIG. 4A. FIG. 4C is a cross-sectional view taken along line IVC-IVC parallel to the YZ plane of the configuration of FIG. 4B. The difference between the laser light source 120 in Modification 2 of Embodiment 1 and the laser light source 100 in Embodiment 1 lies in the shape of the submount 20. The submount 20 in Modification 2 of Embodiment 1 has grooves 20d extending along the resonator length direction between each of the pair of lens support portions 20LS and the laser diode chip 10. In the example shown in FIG. 4B, the groove 20d is adjacent to the pair of lens support portions 20LS, but it is not necessarily adjacent. The size of the groove 20d in the X direction is, for example, 100 μm or more and 500 μm or less, the size in the Y direction is, for example, 50 μm or more and 300 μm or less, and the size from the edge 20ed of the main plane 20s1 in the Z direction is, for example, 1 mm or more and 6 mm or less. The groove 20d does not necessarily need to penetrate in the Z direction. The groove 20d can reduce the influence of heat on the laser diode chip 10 when the collimating lens 30 is joined to the end face 20se of the pair of lens support portions 20LS.

[0044] Next, with reference to FIGS. 5A to 5C, a configuration example of the laser light source 130 in Modification 3 of Embodiment 1 of the present disclosure will be described. FIG. 5A is a perspective view schematically showing a configuration example of the laser light source 130 in Modification 3 of Embodiment 1 of the present disclosure. FIG. 5B is a top view schematically showing the laser light source 130 of FIG. 5A. FIG. 5C is a cross-sectional view taken along the VC-VC line parallel to the YZ plane of the configuration of FIG. 5B. The difference between the laser light source 130 in Modification 3 of Embodiment 1 and the laser light source 100 in Embodiment 1 lies in the configuration of the submount 20. The submount 20 in Modification 3 of Embodiment 1 includes a first submount portion 20p1 and a second submount portion 20p2. The first submount portion 20p1 has a pair of lens support portions 20LS on the upper surface 20us. The first submount portion 20p1 has the above-described U-shaped shape extending in the Z direction. The first submount portion 20p1 can be formed of a ceramic containing at least one selected from the group consisting of, for example, AlN, SiC, and alumina, and an alloy such as CuW. The second submount portion 20p2 is fixed to the upper surface 20us of the first submount portion 20p1 and is located between the pair of lens support portions 20LS. The second submount portion 20p2 has a main plane 20s1 on which the laser diode chip 10 is mounted and a front end face 20fe facing the collimating lens 30. The main plane 20s1 is the surface on the side opposite to the surface fixed to the upper surface 20us among the first submount portion 20p1. In the present disclosure, the front end face 20fe and the back face 20s2 do not necessarily need to be directly connected. In the present disclosure, one side of the front end face 20fe and one side of the main plane 20s1 are in contact, and the side where the front end face 20fe and the main plane 20s1 are in contact defines the edge 20ed of the main plane 20s1. If the thermal conductivity of the second submount portion 20p2 is higher than the thermal conductivity of the first submount portion 20p1, the heat generated from the laser diode chip 10 can be efficiently transferred to the outside. The second submount portion 20p2 can be formed of at least one selected from the group consisting of, for example, Cu, Al, Ag, Fe, Ni, Mo, Cu, W, CuW, CuMo, AlN, SiC, and alumina.The size of the second submount portion 20p2 in the X direction is, for example, 0.5 mm or more and 1.5 mm or less, the size in the Y direction is, for example, 0.1 mm or more and 0.5 mm or less, and the size in the Z direction is, for example, 1 mm or more and 6 mm or less.

[0045] In this submount 20, the position of the second submount portion 20p2 can be adjusted on the first submount portion 20p1 by the separate first submount portion 20p1 and second submount portion 20p2. Like this submount 20, the portion having the main plane 20s1 and the portion having the pair of lens support portions 20LS may be separate. In this submount 20, a gap 20g exists between each of the pair of lens support portions 20LS and the second submount portion 20p2. The size of the gap 20g in the X direction is, for example, 50 μm or more and 300 μm or less. The sizes of the gap 20g in the Y direction and Z direction are determined by the sizes of the second submount portion 20p2 in the Y direction and Z direction, respectively. The gap 20g can reduce the influence of heat on the laser diode chip 10 when the collimating lens 30 is joined to the end faces 20se of the pair of lens support portions 20LS, similar to the laser light source 120 in the second modification of Embodiment 1.

[0046] Next, with reference to FIGS. 6A to 6C, a configuration example of the laser light source 140 in Modification 4 of Embodiment 1 of the present disclosure will be described. FIG. 6A is a perspective view schematically showing a configuration example of the laser light source 140 in Modification 4 of Embodiment 1 of the present disclosure. In FIG. 6A, the laser diode chip 10, the submount 20, and the collimating lens 30 are shown in a separated state, but actually they are joined. FIG. 6B is a top view schematically showing the laser light source 140 of FIG. 6A. FIG. 6C is a cross-sectional view taken along the VIC-VIC line parallel to the YZ plane of the configuration of FIG. 6B. The difference between the laser light source 140 in Modification 4 of Embodiment 1 and the laser light source 100 in Embodiment 1 lies in the configuration of the submount 20. The submount 20 in Modification 4 of Embodiment 1 has a through hole 20h reaching from the main plane 20s1 to the back plane 20s2 and a metal 20m filling the through hole 20h. The portion of the submount 20 other than the through hole 20h can be formed of, for example, ceramic. The metal 20m has a high thermal conductivity and can include at least one selected from the group consisting of, for example, Cu, Al, Ag, Fe, Ni, Mo, Cu, W, and CuMo. The maximum size of the metal 20m in the X direction is, for example, 0.5 mm or more and 1.5 mm or less, and the maximum size in the Z direction is, for example, 1 mm or more and 6 mm or less. The metal 20m may entirely overlap the laser diode chip 10 or partially overlap it in a top view. By arranging the laser diode chip 10 in contact with the metal 20m in the submount 20, the heat generated from the laser diode chip 10 can be efficiently transmitted to the semiconductor laser package 40 through the metal 20m.

[0047] Next, with reference to FIGS. 7A to 7C, a configuration example of the laser light source 150 in Modification 5 of Embodiment 1 of the present disclosure will be described. FIG. 7A is a perspective view schematically showing a configuration example of the laser light source 150 in Modification 5 of Embodiment 1 of the present disclosure. FIG. 7B is a top view schematically showing the laser light source 150 of FIG. 7A. FIG. 7C is a cross-sectional view taken along line VIIc-VIIc parallel to the YZ plane of the configuration of FIG. 7B. The difference between the laser light source 150 in Modification 5 of Embodiment 1 and the laser light source 100 in Embodiment 1 lies in the shape of the collimating lens 30. The collimating lens 30 in Modification 5 of Embodiment 1 has a pair of flat portions 30f and a lens curved surface portion 30c sandwiched between the pair of flat portions 30f. The lens curved surface portion 30c in Modification 5 of Embodiment 1 functions as a FAC lens, similar to the collimating lens 30 in Embodiment 1.

[0048] Next, with reference to FIG. 7D, the advantages of the pair of flat portions 30f in the collimating lens 30 will be described. FIG. 7D is a perspective view schematically showing a state in which the collimating lens 30 in the laser light source 150 of FIG. 7A is joined to the submount 20 using a collet 60. The collet 60 has a bifurcated portion 60a and a support portion 60b connected to the bifurcated portion 60a. The collet 60 has a hollow structure and can adsorb and support the collimating lens 30. Specifically, the tip of the bifurcated portion 60a in the collet 60 adsorbs the pair of flat portions 30f in the collimating lens 30. By holding the support portion 60b with a mounting device and joining the collimating lens 30 to the submount 20 while supporting the collimating lens 30 with the bifurcated portion 60a, a load can be stably applied in a direction perpendicular to the end face 20se of the pair of lens support portions 20LS. In a state where the load is applied, the bonding material between the collimating lens 30 and the end face 20se of the pair of lens support portions 20LS is heated.

[0049] A mirror (not shown) may be provided between the bifurcated portions 60a of the collet 60. Laser da While emitting laser light from the iodine chip 10 in the Z direction, the collimating lens 30 is joined to the submount 20, and the laser light reflected in the Y direction by a mirror (not shown) is received by a light receiving device, whereby the alignment between the collimating lens 30 and the emission end face 10e1 of the laser diode chip 10 can be accurately performed. The light receiving device can be, for example, a power meter, a parallelism measuring device, or a beam profiler.

[0050] (Embodiment 2) Next, with reference to FIGS. 8A to 8D, a basic configuration example of the laser light source in Embodiment 2 of the present disclosure will be described.

[0051] FIG. 8A is a perspective view schematically showing a configuration example of the laser light source 200 in Embodiment 2 of the present disclosure. FIG. 8B is a top view schematically showing the laser light source 200 of FIG. 8A. FIG. 8C is a cross-sectional view taken along line VIIIC-VIIIC parallel to the YZ plane of the configuration of FIG. 8B. FIG. 8D is a rear view schematically showing the laser light source 200 of FIG. 8A. The difference between the laser light source 200 in Embodiment 2 and the laser light source 100 in Embodiment 1 lies in the configuration of the submount 20. The submount 20 in Embodiment 2 includes a third submount portion 20p3 and a fourth submount portion 20p4. The third submount portion 20p3 has a main plane 20s1, a back surface 20s2, and a front end face 20fe. The fourth submount portion 20p4 has a pair of lens support portions 20LS fixed to the main plane 20s1 of the third submount portion 20p3 and a connecting portion 20L connecting the pair of lens support portions 20LS. The connecting portion 20L connects the pair of lens support portions 20LS so as not to obstruct the propagation of the laser light emitted from the emission end face 10e1 of the laser diode chip 10. In this submount 20, the third submount portion 20p3 and the fourth submount portion 20p4 are separate bodies. A portion having the main plane 20s1 and a portion having the pair of lens support portions 20LS may be separate bodies like this submount 20. In FIG. 8A, the third submount portion 20p3, the fourth submount portion 20p4, and the collimating lens 30 are shown in a separated state, but actually they are joined. The pair of lens support portions 20LS and the connecting portion 20L in the fourth submount portion 20p4 are integrally formed.

[0052] As shown in FIGS. 8B and 8C, the connecting portion 20L overlaps with the emitting end face 10e1 of the laser diode chip 10 in a top view. As shown in FIG. 8D, the fourth submount portion 20p4 is disposed on the main plane 20s1 of the third submount portion 20p3 so as to straddle the laser diode chip 10. Since the size of the fourth submount portion 20p4 in the X direction is larger than the size of the third submount portion 20p3 in the X direction, the area of the end faces 20se of the pair of lens support portions 20LS can be widened. As a result, it becomes easy to bond the collimating lens 30 to the end faces 20se of the pair of lens support portions 20LS. The size of the pair of lens support portions 20LS of the fourth submount portion 20p4 in the Y direction may be approximately the same as the size of the collimating lens 30 in the Y direction. The size of the pair of lens support portions 20LS of the fourth submount portion 20p4 in the Y direction may be larger than, equal to, or smaller than the size of the collimating lens 30 in the Y direction. The size of the fourth submount portion 20p4 in the X direction is, for example, 0.5 mm or more and 4 mm or less, the maximum size in the Y direction is, for example, 0.5 mm or more and 2 mm or less, and the size in the Z direction is, for example, 0.5 mm or more and 1 mm or less.

[0053] In the fabrication of the laser light source 200 in Embodiment 2, the steps of bonding the laser diode chip 10 to the main plane 20s1 of the third submount portion 20p3, bonding the fourth submount portion 20p4 to the main plane 20s1 of the third submount portion 20p3 so as to straddle the laser diode chip 10, and bonding the collimating lens 30 to the end faces 20se of the pair of lens support portions 20LS in the fourth submount portion 20p4 may be performed in this order Alternatively, the fourth submount portion 20p4 to which the collimating lens 30 is bonded may be bonded to the third submount portion 20p3 to which the laser diode chip 10 is bonded to the main plane 20s1.

[0054] In the laser light source 200 in Embodiment 2, similar to the laser light source 100 in Embodiment 1, the submount 20 supports the laser diode chip 10 by the main plane 20s1 between the pair of lens support portions 20LS, and supports the collimating lens 30 by the end faces 20se of the pair of lens support portions 20LS. Thereby, alignment between the laser diode chip 10 and the collimating lens 30 becomes easy, and it becomes possible to realize a small-sized laser light source 200. Further, in the laser light source 200 in Embodiment 2, similar to the laser light source 100 in Embodiment 1, even when the laser diode chip 10 is arranged in a face-down state on the submount 20, it is possible to suppress the bonding material from rising up to the emission end face 10e1 of the laser diode chip 10.

[0055] (Modification Example of Embodiment 2) Next, Modification Example 1 and Modification Example 2 of the laser light source 200 in Embodiment 2 of the present disclosure will be described. Descriptions that overlap with the foregoing may be omitted.

[0056] With reference to FIGS. 9A to 9D, a configuration example of the laser light source 210 in Modification 1 of Embodiment 2 of the present disclosure will be described. FIG. 9A is a perspective view schematically showing a configuration example of the laser light source 210 in Modification 1 of Embodiment 2 of the present disclosure. FIG. 9B is a top view schematically showing the laser light source 210 of FIG. 9A. FIG. 9C is a cross-sectional view taken along the IXC-IXC line parallel to the YZ plane of the configuration of FIG. 9B. FIG. 9D is a rear view schematically showing the laser light source 210 of FIG. 9A. The difference between the laser light source 210 in Modification 1 of Embodiment 2 and the laser light source 200 in Embodiment 2 lies in the shape of the fourth submount portion 20p4 in the submount 20. The fourth submount portion 20p4 in Modification 1 of Embodiment 2 has a notch 20co between a pair of lens support portions 20LS in the fourth submount portion 20p4 in Embodiment 2. Due to the notch 20co, as shown in FIGS. 9B and 9C, the connecting portion 20L does not overlap with the emission end face 10e1 of the laser diode chip 10 in a top view. The size of the notch 20co in the X direction is, for example, 0.2 mm or more and 3 mm or less, and the size in the Z direction is, for example, 0.5 mm or more and 1 mm or less. The size of the notch 20co in the Z direction is larger than the size in the Z direction between the end faces 20se of the pair of lens support portions 20LS and the edge 20ed of the main plane 20s1 in the third submount portion 20p3. In the fabrication of the laser light source 210 in Modification 1 of Embodiment 2, alignment between the emission end face 10e1 of the laser diode chip 10 and the fourth submount portion 20p4, and alignment between the emission end face 10e1 of the laser diode chip 10 and the collimating lens 30 are facilitated through the notch 20co.

[0057] Next, with reference to FIGS. 10A to 10D, a configuration example of the laser light source 220 in Modification 2 of Embodiment 2 of the present disclosure will be described. FIG. 10A is a perspective view schematically showing a configuration example of the laser light source 220 in Modification 2 of Embodiment 2 of the present disclosure. FIG. 10B is a top view schematically showing the laser light source 220 of FIG. 10A. FIG. 10C is a cross-sectional view taken along the XC-XC line parallel to the YZ plane of the configuration of FIG. 10B. FIG. 10D is a perspective view schematically showing the fourth submount portion 20p4 and the collimating lens 30 shown in FIG. 10A. The difference between the laser light source 220 in Modification 2 of Embodiment 2 and the laser light source 200 in Embodiment 2 lies in the fourth submount portion 20p4 in the submount 20 and the collimating lens 30. As shown in FIG. 10D, the fourth submount portion 20p4 and the collimating lens 30 in Modification 2 of Embodiment 2 are integrally formed. Since there is no need to bond the fourth submount portion 20p4 and the collimating lens 30, the size of the fourth submount portion 20p4 in the X direction in Modification 2 of Embodiment 2 does not have to be as large as the size of the fourth submount portion 20p4 in the X direction in Embodiment 2. The size of the fourth submount portion 20p4 in the X direction in Modification 2 of Embodiment 2 is, for example, 0.2 mm or more and 3 mm or less, the maximum size in the Y direction is, for example, 0.3 mm or more and 1 mm or less, and the size in the Z direction is, for example, 0.5 mm or more and 1 mm or less.

[0058] The integrally formed fourth submount portion 20p4 and collimating lens 30 can be formed from, for example, at least one of glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic. When the integrally formed fourth submount portion 20p4 and collimating lens 30 are transparent, it becomes easier to align the emission end face 10e1 of the laser diode chip 10 and the collimating lens 30.

[0059] The components in the above-described embodiments and their modifications may be arbitrarily combined.

[0060] (Application Example) The laser light source of the present disclosure can be used, for example, as a light source of a direct diode laser that combines a plurality of laser beams to increase the output. Beam combination is performed by accurately combining the laser beams emitted from a plurality of laser light sources. With a high-intensity laser beam having a wavelength of 570 nm or less, it becomes easy to process a metal such as copper, for example. In the laser light source of the present disclosure, displacement between the laser diode chip and the lens is less likely to occur, so the direction of the optical axis of the laser light emitted from the laser light source to the outside does not deviate significantly. It becomes possible to accurately combine the laser beams emitted from a plurality of laser light sources and improve the beam quality.

Industrial Applicability

[0061] The laser light source of the present disclosure can also be used, for example, in projectors and lighting fixtures.

Explanation of Signs

[0062] 10 Laser diode chip 10a Semiconductor laminate 10b Substrate 10C1 First cladding layer 10C2 Second cladding layer 10e1 Emission end face 10e2 Rear end face 10L Light emitting layer 20 Submount 20co Notch 20d Groove 20ed Edge 20fe Front end face 20fe1 Central end face 20fe2 Both side end faces 20L Connecting portion 20LS Lens support portion 20p1 First submount portion 20p2 Second submount portion 20p3 Third submount portion 20p4 Fourth submount portion 20s1 Main plane 20s2 Back surface End faces of a pair of lens support portions Upper surface of the first submount portion 30 Collimating lens 30c Lens curved surface portion 30f Flat portion 40 Semiconductor laser package 40b Substrate 40L Cover 40w Translucent window 50 Lead terminal 60 Collet 60a Fork portion 60b Support portion 100, 110, 120, 130, 140, 150 Laser light source 200, 210, 220 Laser light source

Claims

1. An edge-emitting laser diode chip having a semiconductor laminate structure including a light-emitting layer, a first end face that emits laser light generated in the light-emitting layer, and a second end face opposite to the first end face, wherein a resonator length is defined by a distance from the first end face to the second end face; A submount having a main plane to which the laser diode chip is fixed, a pair of lens support portions located on both sides of the first end face of the laser diode chip with the main plane interposed therebetween, and a back face located on the side opposite to the main plane; A lens joined to end faces of the pair of lens support portions; A semiconductor laser package that houses the laser diode chip, the lens, and the submount; Comprising; The first end face of the laser diode chip protrudes in the direction of the resonator length from an edge of the main plane; An end face of the pair of lens support portions protrudes in the direction of the resonator length from the first end face of the laser diode chip. A laser light source.

2. The semiconductor laser package according to claim 1, wherein the semiconductor laser package has a substrate that is thermally in contact with the back face of the submount, and hermetically seals the laser diode chip, the submount, and the lens.

3. The submount has a front end face that connects the main plane and the back face; The front end face has a central end face and both side end faces located on both sides of the central end face; The central end face is recessed in the direction of the resonator length from the both side end faces; The edge of the main plane is defined by the main plane and the central end face in the submount. The laser light source according to claim 1 or 2.

4. The submount; A first submount portion having the pair of lens support portions on an upper surface; A second submount portion that is fixed to the upper surface of the first submount portion and has the main plane; Including. The laser light source according to claim 1 or 2.

5. A gap exists between each of the pair of lens support portions and the second submount portion. The laser light source according to claim 4.

6. The submount has grooves extending along the direction of the resonator length between each of the pair of lens support portions and the laser diode chip. The laser light source according to claim 1 or 2.

7. The laser light source according to any one of claims 1 to 6, wherein the submount has a through hole reaching from the main plane to the back surface and a metal filling the through hole.

8. The laser light source according to any one of claims 1 to 7, wherein when viewed from the direction of the resonator length, the center of gravity of the lens is positioned between the pair of lens support portions.

9. The laser light source according to any one of claims 1 to 8, wherein the pair of lens support portions extends in the direction of the resonator length on both sides of the laser diode chip.

Images