Semiconductor laser module, light source device, and fiber laser

Abstract

A semiconductor laser module has, for example, a plurality of semiconductor laser elements, an optical fiber, a first optical component that arranges light output from the plurality of semiconductor laser elements in a fast axis direction at a regular interval, a mirror that reflects a specific wavelength component among the light output from the semiconductor laser elements and arranged at a regular interval in the fast axis direction, forms an external resonator between the plurality of semiconductor laser elements, a diaphragm that is provided in the external resonator and limits the width of the slow axis direction of the laser light so that the light arranged at a regular interval in the fast axis direction is removed from a high-order mode component of multimode laser light, and a condenser lens that couples the laser light output from the external resonator and the output optical fiber.

Description

Technical Field

[0001] This invention relates to semiconductor laser modules, light source devices, and fiber lasers. Background Technology

[0002] Previously, semiconductor laser modules (e.g., Patent Document 1) were known to guide lasers output from multiple light-emitting elements to the end of an optical fiber via multiple optical components.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2019 / 160038 Summary of the Invention

[0006] -The problem the invention aims to solve-

[0007] In such semiconductor laser modules, it is advantageous to be able to output laser light in the desired wavelength band and obtain a semiconductor laser module with low wasted energy consumption.

[0008] Therefore, one of the objectives of this invention is, for example, to obtain improved novel semiconductor laser modules, light source devices, and fiber lasers that can output laser light in the desired wavelength band and reduce unnecessary energy consumption.

[0009] -Methods for solving problems-

[0010] The semiconductor laser module of the present invention includes, for example: a plurality of semiconductor laser elements, each outputting multimode laser as a laser, with their fast axis directions and slow axis directions being substantially the same; a first optical component that arranges the lasers output from the plurality of semiconductor laser elements at open intervals in the fast axis direction; a reflector that reflects specific wavelength components of the light output from the semiconductor laser elements and arranged at open intervals in the fast axis direction, forming an external resonator between the reflector and the plurality of semiconductor laser elements; an aperture disposed within the external resonator that limits the width of the lasers arranged at open intervals in the fast axis direction in the slow axis direction, thereby removing higher-order mode components of the multimode laser from the laser; and a condenser lens that couples the laser output from the external resonator to an output optical fiber.

[0011] In the semiconductor laser module, the aperture may also be located between the reflector and the first optical component.

[0012] In the semiconductor laser module, the front surface reflectivity of the semiconductor laser element may be less than 2%.

[0013] In the semiconductor laser module, the front surface reflectivity of the semiconductor laser element may also be less than 0.5%.

[0014] In the semiconductor laser module, the reflectivity of the reflector may also be 4% or higher.

[0015] In the semiconductor laser module, the aperture and the reflector may also be separate.

[0016] In the semiconductor laser module, the aperture and the reflector can also be integrated.

[0017] In the semiconductor laser module, the focusing lens may also include a first lens, which is an aspherical lens, that focuses multiple parallel laser beams dispersed in the fast axis direction at a convergence point at the end of the output optical fiber, and the reflecting mirror reflects the multiple parallel laser beams to the multiple semiconductor laser elements.

[0018] The light source device of the present invention includes, for example, the semiconductor laser module.

[0019] The fiber laser of the present invention includes, for example, the light source device; an amplifying fiber; and an optical component that guides the laser emitted from the light source device to the amplifying fiber.

[0020] In the fiber laser, the mirror may also reflect the wavelength component of the absorption spectrum of the Yb-doped double-clad fiber, which is located approximately at the center.

[0021] -Invention Effects-

[0022] According to the present invention, semiconductor laser modules, light source devices, and fiber lasers with improved novel structures can be obtained. Attached Figure Description

[0023] Figure 1 This is an exemplary and schematic top view of the semiconductor laser module of the first embodiment.

[0024] Figure 2 This is an exemplary and schematic perspective view of the semiconductor laser module according to the first embodiment.

[0025] Figure 3 This is a graph showing an example of the absorption rate corresponding to the wavelength of the Yb-doped double-clad fiber contained in a fiber laser.

[0026] Figure 4 This is an exemplary and schematic perspective view of the aperture included in the semiconductor laser module of the first embodiment.

[0027] Figure 5This is an illustrative and schematic top view of an enlarged portion of the semiconductor laser module of the first embodiment.

[0028] Figure 6 This is a graph illustrating the relationship between the coupling efficiency of light emitted from the semiconductor laser element of the semiconductor laser module in the first embodiment and the threshold carrier density, which is the amount of current required for laser oscillation of the semiconductor laser module.

[0029] Figure 7 This is a graph illustrating an example of the relationship between slope efficiency and the front surface reflectivity of a semiconductor laser element in the semiconductor laser module of the first embodiment.

[0030] Figure 8 This is an exemplary and schematic perspective view of the aperture included in the semiconductor laser module of the second embodiment.

[0031] Figure 9 This is an illustrative and schematic top view of a portion of the semiconductor laser module of the third embodiment.

[0032] Figure 10 This is an exemplary schematic diagram showing multiple laser elements, a reflector, and two focusing lenses as viewed in the slow axis direction of the semiconductor laser module in the fourth embodiment.

[0033] Figure 11 This is an illustrative schematic diagram showing the reflector and two focusing lenses as viewed in the slow axis direction of the semiconductor laser module in the reference example.

[0034] Figure 12 This is an exemplary schematic structural diagram of the fiber laser according to the fifth embodiment. Detailed Implementation

[0035] The following are exemplary embodiments of the present invention. The structure of the embodiments shown below, and the effects and results (effects) resulting from such structure, are examples. The present invention can also be implemented in ways other than those disclosed in the embodiments below. Furthermore, according to the present invention, at least one of various effects (including derivative effects) obtained through the structure can be obtained.

[0036] The various embodiments shown below have the same structure. Therefore, based on the structure of each embodiment, the same functions and effects can be obtained. Furthermore, the same reference numerals are used for these same structures below, and repeated descriptions are sometimes omitted.

[0037] In this specification, ordinal numbers are assigned for the purpose of distinguishing parts, components, locations, directions, light, etc. Furthermore, ordinal numbers do not indicate priority or order, nor do they specify the quantity.

[0038] In the diagrams, arrow X represents the X direction, arrow Y represents the Y direction, and arrow Z represents the Z direction. The X, Y, and Z directions intersect and are orthogonal to each other. The direction following arrow X is called the opposite direction of the X direction, the direction following arrow Y is called the opposite direction of the Y direction, and the direction following arrow Z is called the opposite direction of the Z direction. Furthermore, the diagrams are illustrative, and the shapes, dimensions, and proportions of the parts may sometimes differ from reality.

[0039] [First Implementation]

[0040] Figure 1 This is a top view of the semiconductor laser module 10 according to the first embodiment. Furthermore, Figure 2 This is a 3D view of the semiconductor laser module 10.

[0041] The semiconductor laser module 10 includes: a base 24; a plurality of semiconductor laser elements 12; an optical system 14 respectively disposed corresponding to the semiconductor laser elements 12; an output section 18; and a terminal section 20.

[0042] The output section 18 supports the optical fiber 68 for transmitting output light. Furthermore, the terminal section 20 is a connection terminal for the conductor of the wiring that supplies power from an external power source to the semiconductor laser element 12. The optical fiber 68 is an example of an output optical fiber.

[0043] like Figure 1 , Figure 2 As shown, the base 24 supports the components contained in the semiconductor laser module 10. The base 24 can also be referred to as a support member or a mounted member.

[0044] like Figure 2 As shown, the base 24 has a stepped height difference portion 38. The height difference portion 38 has a plurality of height difference surfaces 40 that are equally spaced in the Z direction in the opposite direction to the Y direction. The height difference surfaces 40 are generally planar, all facing the Z direction, and intersecting and orthogonal to the Z direction.

[0045] Semiconductor laser elements 12 of the same specifications are mounted on each of the elevation difference surfaces 40. Each of the multiple semiconductor laser elements 12 outputs laser light with the Z-direction and its opposite direction defined as the fast axis direction, and the Y-direction and its opposite direction defined as the slow axis direction. In other words, the fast axis directions and slow axis directions of the multiple semiconductor laser elements 12 are approximately the same. Furthermore, in this embodiment, each of the semiconductor laser elements 12 outputs multimode laser light. Additionally, in this embodiment, the semiconductor laser elements 12 are mounted on a sub-base 42 to form a sub-heat sink, but this is not a limitation; for example, they can also be housed within a housing and modularized.

[0046] In addition, collimating lenses 58 and 60 and a mirror 62 are installed on each elevation difference surface 40. On each elevation difference surface 40, the laser output from the semiconductor laser element 12 travels along the X direction, is first collimated in the fast axis direction by collimating lens 58, and then collimated in the slow axis direction by collimating lens 60, before proceeding toward mirror 62.

[0047] Mirror 62 reflects laser light directed in the X direction, causing it to align in the Y direction. Furthermore, in the reflection of the laser light in mirror 62, the fast axis direction remains unchanged, but the slow axis direction changes from the Y direction and its opposite to the X direction and its opposite.

[0048] The laser beam, reflected by each mirror 62 and directed towards the Y direction, is coupled to the end of the optical fiber 68 via the aperture 111, the reflector 511, and the condenser lenses 64 and 65. The condenser lens 64 focuses the laser beam along the fast axis (Z direction and the opposite direction), and the condenser lens 65 focuses the laser beam along the slow axis (X direction and the opposite direction). The reflector 511 and the aperture 111 will be described in detail later.

[0049] In the above structure, since the multiple height difference surfaces 40 are staggered at a given interval in the Z direction, in other words, their positions in the Z direction are different, the multiple lasers reflected by the mirror 62 and traveling in the Y direction are arranged with a gap in the Z direction before being input into the reflecting mirror 511. In other words, the height difference section 38 (height difference surface 40), multiple semiconductor laser elements 12, collimating lenses 58 and 60, and mirror 62 are provided so that the multiple lasers input into the reflecting mirror 511 are arranged with a gap in the Z direction. In this embodiment, the collimating lenses 58 and 60 and mirror 62 between the semiconductor laser elements 12 and the reflecting mirror 511 are referred to as the optical system 14. Each optical component included in the optical system 14 is an example of the first optical component. In addition, the structure of the height difference section 38, the height difference surface 40, and the optical system 14 is not limited to Figure 1 , Figure 2 As an example, any structure can be used as long as it enables the multiple lasers input to the reflector 511 to be arranged with a gap in the Z direction. Furthermore, the semiconductor laser module 10 can have multiple parallel structures including a height difference section 38, a height difference surface 40, and an optical system 14, from which multiple lasers input to the reflector 511 are arranged with a gap in the Z direction. Additionally, the term "multiple lasers arranged with a gap" refers to the optical axes of the multiple lasers being arranged with a gap.

[0050] Figure 3 This is a graph showing an example of the absorptivity corresponding to the wavelength of the Yb-doped double-clad fiber contained in the fiber laser. In the semiconductor laser module 10, the main output, for example... Figure 3In the case of laser light containing a component of band B (λc ± 3 nm) with a center wavelength of λc: 976 nm, the semiconductor laser module 10 can be used as part of the excitation light source to improve the output efficiency of a fiber laser consisting of a Yb-doped double-clad fiber used for amplification. However, it is difficult to output laser light of band B using only the normal laser oscillation of the semiconductor laser element 12.

[0051] Therefore, in the semiconductor laser module 10, a reflector 511, which selectively reflects a specific wavelength component, namely the component of wavelength band B, such as a VBG element (volume bragg grating), is provided, and an external resonator is formed between the semiconductor laser element 12 and the reflector 511. Thus, the semiconductor laser module 10 can be configured to output laser light in wavelength band B, which is different from the oscillation wavelength of the semiconductor laser element 12.

[0052] In this structure, it was determined that in the laser output from the external resonator and coupled to the optical fiber 68 via the focusing lenses 64 and 65, the driving power corresponding to the semiconductor laser element 12 increases, particularly the beam divergence angle in the slow axis direction. In this case, it is considered to install an aperture that physically limits the divergence angle in the slow axis direction. However, if the divergence angle in the slow axis direction is limited for the laser output from the external resonator, the output of the laser from the semiconductor laser module 10 will decrease due to the amount of limitation.

[0053] Therefore, the inventors discovered through repeated in-depth research that by inserting an aperture 111, which removes the higher-order mode components contained in the multimode laser, into an external resonator, the higher-order mode components of the multimode laser can be removed by the aperture 111. This can suppress the output reduction caused by the aperture 111 while limiting the divergence angle of the laser in the slow axis direction.

[0054] That is, in this embodiment, such as Figure 1 , Figure 2 As shown, an aperture 111 is inserted within an external resonator, specifically between the mirror 511 and the plurality of semiconductor laser elements 12. In this case, the plurality of lasers arranged at open intervals in the Z direction pass through the aperture 111. That is, the aperture 111 restricts the width of the laser in the slow axis direction for each of the lasers arranged at open intervals in the Z direction, thereby removing higher-order components of the multimode laser.

[0055] Through experimental research, the inventors compared the output of the laser for the same supply current (2 to 15 [A]) supplied to the semiconductor laser module 10 with the following three structures (1) to (3) using experimental research.

[0056] (1) Referring to Example 1: It does not have the structure of aperture 111 at all;

[0057] (2) Reference Example 2: A structure in which an aperture 111 is provided outside the external resonator, that is, between the mirror 511 and the condensing lens 64, instead of being provided inside the external resonator;

[0058] (3) Present Embodiment: A structure in which the aperture 111 is provided inside the external resonator.

[0059] Accordingly, the reduction rate of the laser output in the structure of Reference Example 2 relative to the laser output in the structure of Reference Example 1 is 2 to 18[%]. In contrast, the reduction rate of the laser output in the structure of the present embodiment relative to the laser output in the structure of Reference Example 1 is 0 to 6[%]. As such, it was confirmed that by disposing the aperture 111 not outside the external resonator as in Reference Example 2 but inside the external resonator as in the present embodiment, the output reduction relative to the structure that does not include the aperture 111 at all (Reference Example 1) can be significantly suppressed.

[0060] Figure 4 is a perspective view showing a specific structural example of the aperture 111A (111). The aperture 111A has a substantially constant thickness in the X direction and a substantially constant width in the X direction, and has a rectangular plate-like shape extending along the Z direction. This aperture 111A has two shielding portions 111a that extend parallel to each other at equal intervals along the Z direction, and a U-shaped, notched opening O that opens in the Z direction is provided between the two shielding portions 111a. In the aperture 111A, a plurality of lasers arranged at intervals in the Z direction pass through this opening O. Within the range where the plurality of lasers pass at intervals in the Z direction, the position of the opening O in the X direction and the width Ws (the interval between the shielding portions 111a) are constant regardless of the position in the Z direction. Further, the width Ws of the opening O in the X direction, which is the slow axis direction of the aperture 111A, is set to a size capable of removing high-order components of multimode laser. Figure 5 is a plan view showing an enlarged part of the semiconductor laser module 10. As shown in Figure 5 , when the light emission width of the semiconductor laser element 12 in the slow axis direction is defined as h, the maximum divergence angle is defined as θ, and the focal length of the collimator lens 60 in the slow axis direction is defined as f, the width Ws is set, for example, to satisfy Ws < h + 2f·tan(θ / 2). In this structure, the shielding portions 111a partially block the laser at the ends in the X direction and the direction opposite to the X direction of the passage region intersecting the Y direction of the laser, thereby removing high-order components of the multimode laser.

[0061] Furthermore, in the external resonator configuration, the aperture 111A can remove higher-order components of the multimode laser from both the laser beam from the semiconductor laser element 12 toward the reflector 511 and the laser beam from the reflector 511 toward the semiconductor laser element 12. This allows for more reliable removal of higher-order components of the multimode laser.

[0062] Furthermore, through in-depth research by the inventors on the structure in which the aperture 111 is located within the external resonator as in this embodiment, it was determined that the lower the reflectivity of the front surface of the semiconductor laser element 12, the higher the output efficiency of the laser for the supplied current. This was investigated.

[0063] First, the reflectivity R is calculated by replacing the front surface of the reflector 511 and the semiconductor laser element 12 with a single mirror. eff This becomes the next equation (1).

[0064] [Mathematical Expression 1]

[0065]

[0066] Here, R f C: Reflectivity of the front surface of semiconductor laser element 12; R: Coupling efficiency of light emitted from the front surface (emission end face) of semiconductor laser element 12 to reflector 511. VBG : The reflectivity of mirror 511.

[0067] According to equation (1), the gain g of the semiconductor laser element 12 is expressed as in the following equation (2).

[0068] [Mathematical Expression 2]

[0069]

[0070] Here, α i : Transparent carrier density, L: Resonator length of semiconductor laser element 12, R HR : Reflectivity of the back surface of semiconductor laser element 12.

[0071] According to equation (2), the threshold carrier density N in the external resonator is... th As shown in the following equation (3).

[0072] [Mathematical Expression 3]

[0073]

[0074] Here, N tr Γ: Transparent carrier density, Γ: Active layer confinement count, G0: Gain count.

[0075] The threshold carrier density N in equation (3) thThis represents the amount of current required for laser oscillation. The larger this value, the more difficult it is for the laser to oscillate, meaning that the output (output efficiency) of the laser is lower for the supplied current.

[0076] Figure 6 It concerns the front surface reflectivity R. f Two examples illustrate the relationship between coupling efficiency C and threshold carrier density N. th A diagram of the relationships. From Figure 6 It can be seen that the reflectivity R of the front surface is... f The lower the threshold carrier density N, the better. th The higher the value, the more difficult it is for the semiconductor laser element 12 to oscillate.

[0077] Furthermore, the coupling efficiency C of the higher-order mode components is assumed to be in the range of 0 to 0.2. However, if the higher-order mode components are included in the external resonator, that is, if the oscillation is to include components with C = 0 to 0.2, then from Figure 6 It is known that higher power is required. In contrast, according to this embodiment, since oscillation can occur simultaneously with the removal of higher-order mode components through the aperture 111 within the resonator (external resonator), the corresponding current supply can be reduced, presumably thereby improving output efficiency. Furthermore, the threshold carrier density N becomes [value missing] for the component where C = 0 to 0.2. th Reflectivity R of the front surface f The lower the value, the greater the tendency to increase, presumably due to the effect of removing the aforementioned higher-order mode components on the front surface reflectivity R. f This is more pronounced in low-end semiconductor laser elements 12.

[0078] Next, consider the light output when the front surfaces of the reflector 511 and the semiconductor laser element 12 are replaced by a single mirror. Let the light output from the front surface of the system be set as P. f Set the light output from the rear surface of the system to P b Let the forward beam at the exit end face of the semiconductor laser element 12 be P' f The backlight at the back and front of the semiconductor laser element 12 is set as P'. b Then P' b With P' f The relationship is expressed as shown in equation (4) below.

[0079] [Mathematical Expression 4]

[0080]

[0081] Furthermore, the proportion F of the energy externally coupled to the semiconductor laser element 12 that is extracted from the front surface through the reflector 511 is... f As shown in equation (5) below.

[0082] [Mathematical Expression 5]

[0083]

[0084] Here, T eff : The transmittance of the front surface of the system.

[0085] Furthermore, the slope efficiency SE of the semiconductor laser element 12 is expressed as in the following equation (6).

[0086] [Mathematical Expression 6]

[0087]

[0088] Here, η i Internal quantum efficiency, α m : Mirror loss in the system.

[0089] Figure 7 Equation (6) represents the slope efficiency SE and the front surface reflectivity R of the semiconductor laser element 12. f A graph showing the relationship. Here, we assume the coupling efficiency C = 1 and the reflectivity R of mirror 511 is... VBG =10% [%. The higher the reflectivity of the 511 mirror, the greater the mirror loss and the lower the light output; therefore, a value of 10% is generally used. From Figure 7 It can be seen that the reflectivity R of the front surface is... f The smaller the slope, the higher the slope efficiency SE. Therefore, it can be seen that the slope efficiency SE tends to increase more in the region where the reflectivity of the front surface of the semiconductor laser element 12 is below 2%.

[0090] Through in-depth research based on experiments and simulations, the inventors determined, from the aforementioned perspective, that the front surface reflectivity of the semiconductor laser element 12 is preferably 2% or less, more preferably 0.5% or less. Furthermore, this front surface reflectivity is set to 0.01% or more. Moreover, it was determined that the reflectivity of the mirror 511 constituting such an external resonator is preferably 4% or more. This is to ensure wavelength selectivity.

[0091] As described above, the semiconductor laser module 10 according to this embodiment can output laser light in the desired wavelength band, and can limit the divergence angle in the slow axis direction while improving output efficiency, that is, reducing useless energy consumption.

[0092] Furthermore, in this embodiment, the aperture 111 and the reflector 511 are separate from each other. With this structure, for example, it is possible to obtain advantages such as the ability to adjust the setting position and orientation (angle) of the aperture 111 separately from the reflector 511.

[0093] [Second Implementation]

[0094] Figure 8 This is a perspective view showing the aperture 111B (111) included in the semiconductor laser module 10 of the second embodiment. The aperture 111B can be provided in place of the aperture 111A of the semiconductor laser module 10 of the first embodiment, and in this structure, the effects of having the aperture 111 can also be obtained.

[0095] In this embodiment, the two shielding portions 111a in the aperture 111B are configured to be separate from each other. In this case, it is possible to obtain the advantage that the output characteristics of the semiconductor laser module 10 can be adjusted by finely adjusting the width Ws of the gap G between the two shielding portions 111a.

[0096] [Third Implementation]

[0097] Figure 9 This is a top view of a portion of the semiconductor laser module 10 according to the third embodiment. Figure 9 The structure shown can be replaced in the semiconductor laser module 10 of the first embodiment described above, and the effect of having the aperture 111 can also be obtained in this structure.

[0098] In this embodiment, the aperture 111 and the reflector 511 are integrated. In this case, compared to separately assembling the aperture 111 and the reflector 511 on the base 24, the manufacturing time and cost of the semiconductor laser module 10 can sometimes be reduced. In this case, on the base 24, only the aperture 111 (part of the aperture 111 and reflector 511 sub-assemblies) can be fixed to the base 24, or only the reflector 511 (part of the sub-assemblies) can be fixed to the base 24. Furthermore, the aperture 111 or the reflector 511 is fixed to the base 24, for example, via a bonding material such as an ultraviolet-curable adhesive.

[0099] [Fourth Implementation]

[0100] Figure 10 This is an illustrative schematic diagram showing a plurality of semiconductor laser elements 12, a reflector 511, and two focusing lenses 64 and 65 as viewed in the slow axis direction of the semiconductor laser module 10 in the fourth embodiment. In this embodiment, as in the first embodiment, an external resonator is formed between a reflector 511 and a plurality of semiconductor laser elements 12 positioned differently in the Z direction. In this structure, preferably, as in... Figure 10As shown, the reflector 511 is configured with a constant thickness in the Y direction and orthogonal to the Y direction. Multiple lasers dispersed in the Z direction travel in parallel in the Y direction and are incident on the reflector 511 at approximately right angles, reflecting in the opposite direction of the Y direction. Here, we examine the state in which the coupling efficiency of the multiple lasers to the optical fiber 68 is maximized when the lasers incident on the condenser lens 64 travel in parallel in the Y direction.

[0101] Figure 11 This is a reference example of a condenser lens 64R, which is configured as a spherical lens (cylindrical lens), observed in the slow-axis direction. For example... Figure 11 As shown, when the condenser lens 64R is configured as a spherical lens, due to the aberrations of the condenser lens 64R, the desired coupling efficiency can be obtained for lasers incident radially onto the reflector 511. In other words, it is difficult to obtain the desired coupling efficiency for multiple lasers incident approximately at right angles onto the reflector 511.

[0102] Therefore, in this embodiment, the condenser lens 64 is set as an aspherical (non-cylindrical) cylindrical lens to achieve this. Figure 10 The state is as follows. Thus, an external resonator is formed between a reflector 511 and multiple semiconductor laser elements 12 positioned differently in the Z direction, and the multiple lasers from each external resonator are focused at a convergence point at the end of an optical fiber 68, enabling coupling with the desired coupling efficiency. The focusing lens 64 is an example of the first lens.

[0103] [Fifth Implementation]

[0104] Figure 12 This is an exemplary schematic diagram of the fiber laser 94 according to the fifth embodiment. The fiber laser 94 includes a light source device 80, a pump combiner 96, a rare-earth-added fiber 98, an output fiber 100, a high-reflectivity FBG 102 (FBG: fiber Bragg grating), and a low-reflectivity FBG 104.

[0105] The light source device 80 functions as the excitation light source for the fiber laser 94 and has multiple semiconductor laser modules 10 of the above embodiment arranged side by side. The output ends of the optical fibers 68 that transmit the laser light output from each semiconductor laser module 10 are coupled to multiple input ports of a multi-input single-output pump combiner 96. The input end of a rare-earth-added fiber 98 is connected to the output port of the pump combiner 96. The input end of an output fiber 100 is connected to the output end of the rare-earth-added fiber 98. In addition, other structures can be used instead of the pump combiner 96 as the input section for inputting the laser light output from the multiple semiconductor laser modules 10 to the rare-earth-added fiber 98. For example, the optical fibers 68 corresponding to the semiconductor laser modules 10 can be arranged in a specific configuration, and the laser light output from the multiple optical fibers 68 can be incident on the input end of the rare-earth-added fiber 98 using an incident section including an optical system with lenses. In this way, a fiber laser 94 with the light source device 80 of this embodiment as the excitation light source is constructed.

[0106] In the fiber laser 94, laser beams output from the semiconductor laser module 10 are coupled via fiber 68 using a pump combiner 96 and output from its output port. The pump combiner 96, serving as the input section, inputs the laser beam, which serves as the excitation light, output from its output port to the input end of the rare-earth-added fiber 98. In the fiber laser 94, a resonator is formed by the rare-earth-added fiber 98, a high-reflectivity FBG 102, and a low-reflectivity FBG 104. Fiber 68 and the pump combiner 96 are examples of optical components.

[0107] In the rare-earth-doped fiber 98, the propagating excitation light is absorbed by rare-earth elements doped in the fiber core, resulting in a reversal distribution between the ground state and metastable energy levels, thus emitting light. This emitted light is amplified by the rare-earth-doped fiber 98 and oscillated by a resonator formed together with a high-reflectivity FBG 102 and a low-reflectivity FBG 104 to induce laser oscillation. In this way, laser light is generated in the fiber laser 94 through laser oscillation. The generated laser light is output from the output fiber 100, which is connected to the output end of the rare-earth-doped fiber 98. The rare-earth-doped fiber 98 is, for example, a Yb-doped double-clad fiber, an example of an amplification fiber.

[0108] The above embodiments of the present invention have been illustrated, but these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other ways, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of various structures, shapes, etc. (construction, type, orientation, form, size, length, width, thickness, height, quantity, configuration, position, material, etc.) can be appropriately modified for implementation.

[0109] Industrial availability

[0110] This invention can be used in semiconductor laser modules, light source devices, and fiber lasers.

[0111] -Symbol Explanation-

[0112] 10… Semiconductor laser module

[0113] 12… Semiconductor laser components

[0114] 14…Optical System

[0115] 18… Output Department

[0116] 20…Terminal section

[0117] 24…base

[0118] 38…Elevation Difference

[0119] 40…Elevation Difference Surface

[0120] 42…Sub-base

[0121] 58… Collimating lens (first optical component)

[0122] 60… Collimating lens (first optical component)

[0123] 62… Mirror (First Optical Component)

[0124] 64… Condensing lens (first lens)

[0125] 64R…Condenser Lens

[0126] 65… Condensing lens

[0127] 68… Optical fiber (output fiber, optical components)

[0128] 80…light source device

[0129] 94… Fiber laser

[0130] 96… Pump combiner (optical component)

[0131] 98… Rare earth-added optical fiber (optical fiber for amplification)

[0132] 100… Output fiber

[0133] 102…High-reflectivity FBG

[0134] 104…Low-reflectivity FBG

[0135] 111, 111A, 111B... aperture

[0136] 111a…Shielding section

[0137] 511…reflector

[0138] B…band

[0139] G…gap

[0140] O…opening

[0141] Ws…width

[0142] X…direction

[0143] Y...direction

[0144] Z…direction

[0145] λc…center wavelength. Claims (as amended under Article 19 of the Treaty) 1. (Modified) A semiconductor laser module, characterized in that it comprises: Multiple semiconductor laser elements each output multimode laser as a laser, with their fast axis directions and slow axis directions being approximately the same as each other; The first optical component arranges the lasers output from the plurality of semiconductor laser elements at open intervals along the fast axis direction; A reflector reflects a specific wavelength component of the light output from the semiconductor laser elements and arranged at open intervals in the fast axis direction, forming an external resonator between the plurality of semiconductor laser elements. An aperture, disposed within the external resonator, limits the width of the laser beams spaced apart in the fast axis direction in the slow axis direction, such that higher-order mode components of the multimode laser are removed from the laser beams; and A focusing lens couples the laser output from the external resonator to the output optical fiber. The aperture is located between the reflector and the first optical component. In the external resonator configuration, the higher-order components of the multimode laser are removed from both the laser beam from the semiconductor laser element toward the reflector and the laser beam from the reflector toward the semiconductor laser element. 2. (Delete) 3. (Modified) The semiconductor laser module according to claim 1, wherein, The front surface reflectivity of the semiconductor laser element is less than 2%. 4. The semiconductor laser module according to claim 3, wherein, The front surface reflectivity of the semiconductor laser element is less than 0.5%. 5. (Modified) The semiconductor laser module according to claim 1, wherein, The reflectivity of the mirror is 4% or higher. 6. (Modified) The semiconductor laser module according to claim 1, wherein, The aperture and the reflector are separated. 7. (Modified) The semiconductor laser module according to claim 1, wherein, The aperture and the reflector are integrated. 8. The semiconductor laser module according to claim 1, wherein, The condenser lens includes a first lens, which is an aspherical lens, that focuses multiple parallel laser beams dispersed in the fast axis direction at a convergence point at the end of the output optical fiber. The reflector reflects the plurality of parallel laser beams onto the plurality of semiconductor laser elements. 9. (Modified) A light source device, characterized in that it comprises the semiconductor laser module as described in claim 1. 10. A fiber laser, characterized in that it comprises: The light source device according to claim 9; Fiber optic for amplification; and An optical component guides the laser light output from the light source device to the amplifying optical fiber. 11. The fiber laser according to claim 10, wherein, The mirror reflects the wavelength component of the absorption spectrum of the Yb-doped double-clad fiber, which is located approximately at the center.

Claims

1. A semiconductor laser module, characterized in that, have: Multiple semiconductor laser elements each output multimode laser as a laser, with their fast axis directions and slow axis directions being approximately the same as each other; The first optical component arranges the lasers output from the plurality of semiconductor laser elements at open intervals along the fast axis direction; A reflector reflects a specific wavelength component of the light output from the semiconductor laser elements and arranged at open intervals in the fast axis direction, forming an external resonator between the plurality of semiconductor laser elements. An aperture, disposed within the external resonator, limits the width of the laser beams arranged at open intervals in the fast axis direction in the slow axis direction, so as to remove the higher-order mode components of the multimode laser from the laser beams. and A focusing lens couples the laser output from the external resonator to the output optical fiber.

2. The semiconductor laser module according to claim 1, wherein, The aperture is located between the reflector and the first optical component.

3. The semiconductor laser module according to claim 1 or 2, wherein, The front surface reflectivity of the semiconductor laser element is less than 2%.

4. The semiconductor laser module according to claim 3, wherein, The front surface reflectivity of the semiconductor laser element is less than 0.5%.

5. The semiconductor laser module according to claim 1 or 2, wherein, The reflectivity of the mirror is 4% or higher.

6. The semiconductor laser module according to claim 1 or 2, wherein, The aperture and the reflector are separated.

7. The semiconductor laser module according to claim 1 or 2, wherein, The aperture and the reflector are integrated.

8. The semiconductor laser module according to claim 1, wherein, The condenser lens includes a first lens, which is an aspherical lens, that focuses multiple parallel laser beams dispersed in the fast axis direction at a convergence point at the end of the output optical fiber. The reflector reflects the plurality of parallel laser beams onto the plurality of semiconductor laser elements.

9. A light source device, characterized in that, It has the semiconductor laser module as described in claim 1 or 2.

10. A fiber laser, characterized in that, have: The light source device according to claim 9; Fiber optic for amplification; and An optical component guides the laser light output from the light source device to the amplifying optical fiber.

11. The fiber laser according to claim 10, wherein, The mirror reflects the wavelength component of the absorption spectrum of the Yb-doped double-clad fiber, which is located approximately at the center.

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