Laser light source device and laser processing device

Abstract

A laser light source device (1) comprising: a first light emitting unit (101) that emits first laser light (L1); a second light emitting unit (102) that emits second laser light (L2); an optical element (20) that condenses the first laser light (L1) and the second laser light (L2); a wavelength dispersion element (30) into which the emitted first laser light (L1) and second laser light (L2) enter and by which the optical axes of the incident first laser light (L1) and second laser light (L2) are aligned and the light is emitted ; and a partially reflecting mirror (40) that returns, by reflection, a part of the first laser light (L1) and a part of the second laser light (L2) emitted from the wavelength dispersion element (30), and transmits the other part of the first laser light (L1) and the other part of the second laser light (L2) emitted from the wavelength dispersion element (30), wherein the partially reflecting mirror (40) has a wavelength-dependent reflectance.

Description

[Technical field]

[0001] The present disclosure relates to a laser source device and a laser processing device. [Background technology]

[0002] 2. Description of the Related Art Laser light source devices that include a laser element in which a plurality of light emitting sections are integrated are known.

[0003] For example, the laser light source device disclosed in Patent Document 1 includes such a laser element, a fast axis collimator, a diffraction grating, and a partial reflection mirror in this order along the optical path. In this laser light source device, an external resonator is formed between the laser element and the partial reflection mirror.

[0004] In such a laser light source device, the multiple laser beams emitted from the multiple light emitting units are incident on the diffraction grating at different angles of incidence, and the multiple laser beams have different oscillation wavelengths depending on the angles of incidence. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-120560 A Summary of the Invention [Problem to be solved by the invention]

[0006] Meanwhile, the feedback light efficiency is used as an index showing the degree of light that the multiple laser lights reflected by the partial reflection mirror return to the multiple light emitting units. In a conventional laser light source device, the multiple laser lights are incident on the diffraction grating at different angles of incidence and have different oscillation wavelengths, so that the diffraction efficiency of the diffraction grating for each of the multiple laser lights is different. For this reason, it is difficult to control the feedback light efficiency of each of the multiple light emitting units, and for example, the feedback light efficiency of each of the multiple light emitting units varies. As a result, problems such as a decrease in oscillation stability occur in the multiple laser lights.

[0007] In view of the above, an object of the present disclosure is to provide a laser light source device and the like that is capable of controlling the feedback light efficiency of each of a plurality of light-emitting sections. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of a laser light source device according to the present disclosure includes a first light-emitting unit that emits a first laser light, a second light-emitting unit that emits a second laser light, an optical element that collects the first laser light and the second laser light, a wavelength dispersion element into which the first laser light and the second laser light emitted from the optical element are incident and which emits the first laser light and the second laser light by cohering their optical axes, and a partial reflection mirror that reflects and returns a portion of the first laser light emitted from the wavelength dispersion element and a portion of the second laser light emitted from the wavelength dispersion element, and transmits another portion of the first laser light emitted from the wavelength dispersion element and another portion of the second laser light emitted from the wavelength dispersion element, and the reflectance of the partial reflection mirror has wavelength dependence.

[0009] Moreover, one aspect of a laser processing apparatus according to the present disclosure includes the above-described laser source device. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a laser light source device or the like capable of controlling the feedback light efficiency of each of a plurality of light-emitting sections. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a laser light source device according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing a simulation result of the external feedback light amplitude and the ASE amplitude for a plurality of laser beams of a laser light source device according to a comparative example. [Diagram 3] FIG. 3 is a diagram showing reflection spectra of the partial reflecting mirror according to the first embodiment and a partial reflecting mirror according to a comparative example. [Figure 4] FIG. 4 is a schematic diagram showing the laser processing apparatus according to the first embodiment. [Diagram 5] FIG. 5 is a perspective view showing a configuration of a plurality of laser elements included in the laser source device according to the second embodiment. [Figure 6] FIG. 6 is a perspective view showing a configuration of a plurality of laser elements included in a laser source device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement and connection of the components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0013] In addition, each figure is a schematic diagram and is not necessarily precisely illustrated. Therefore, the scales and the like are not necessarily the same in each figure. In each figure, the same reference numerals are given to substantially the same configurations, and duplicated explanations are omitted or simplified.

[0014] (Embodiment 1) [Configuration of laser light source device] First, the configuration of a laser light source device 1 according to the present embodiment will be described with reference to FIG.

[0015] FIG. 1 is a schematic diagram showing the configuration of a laser light source device 1 according to the present embodiment.

[0016] 1, the laser light source device 1 is a light emitting device including a laser element 10, an optical element 20, a wavelength dispersion element 30, and a partial reflection mirror 40. The laser element 10, the optical element 20, the wavelength dispersion element 30, and the partial reflection mirror 40 are arranged in this order along the optical path of a plurality of laser beams L100 emitted from the laser element 10. In addition, in FIG. 1, the behavior of the plurality of laser beams L100 is indicated by arrows.

[0017] The laser light source device 1 is a light emitting device that outputs output light Lo by a so-called DDL (Direct Diode Laser) method that directly uses laser light emitted from a laser element 10. The laser light source device 1 using the DDL method is characterized by high efficiency since it does not convert laser light, and by selecting the material of the laser element 10 (e.g., semiconductor material, etc.), processing can be performed with laser light ranging from ultraviolet to infrared.

[0018] In this embodiment, the laser light source device 1 outputs output light Lo in the violet to blue region (wavelength region of 380 nm to 480 nm). More specifically, the output light Lo is light having a peak wavelength in the violet to blue region. Such a laser light source device 1 is used, for example, to perform fine processing of materials such as metals or resins.

[0019] Next, components of the laser source device 1 will be described.

[0020] The laser element 10 is a semiconductor laser having a multi-emitter structure in which a plurality of light-emitting sections 100 are integrated into one element, and emits a plurality of laser beams L100. Specifically, the laser element 10 is a nitride-based semiconductor laser made of a nitride-based semiconductor material, and emits laser beams L100 in the purple to blue region, for example.

[0021] The plurality of light-emitting units 100 is made up of 38 light-emitting units 100 including the first light-emitting unit 101 to the 38th light-emitting unit 138. Here, when there is no need to distinguish between the first light-emitting unit 101 to the 38th light-emitting unit 138, they will be referred to as light-emitting unit 100. Note that the plurality of light-emitting units 100 may be made up of more or less than 38 light-emitting units 100.

[0022] As shown in FIG. 1, the laser element 10 is a laser bar that is long in one direction.

[0023] The laser element 10 has a substrate, a nitride-based semiconductor laser stacked structure, a p-side electrode, and an n-side electrode (all of which are omitted in FIG. 1).

[0024] The substrate has a first main surface and a second main surface. The second main surface is the surface opposite to the first main surface and faces away from the first main surface. In this embodiment, the first main surface is a p-side surface that is a front surface, and the second main surface is an n-side surface that is a back surface.

[0025] The substrate may be, for example, a semiconductor substrate such as a nitride semiconductor substrate, etc. In this embodiment, a hexagonal n-type GaN substrate is used as the substrate.

[0026] The nitride semiconductor laser laminate structure is a nitride semiconductor layer laminate in which a plurality of nitride semiconductor layers, each made of a nitride semiconductor material, are laminated. The nitride semiconductor laser laminate structure is formed above the first main surface of a substrate. For example, the nitride semiconductor laser laminate structure has an n-type cladding layer, an active layer, a p-type cladding layer, and a p-type contact layer laminated in this order on the first main surface of a substrate. In this embodiment, the n-type cladding layer is made of n-type AlGaN, the active layer is made of undoped InGaN, the p-type cladding layer is made of p-type AlGaN, and the p-type contact layer is made of p-type GaN.

[0027] In addition to these nitride semiconductor layers, the nitride semiconductor laser laminate structure may be provided with other nitride semiconductor layers such as an optical guide layer and an overflow suppression layer. Also, an insulating film having an opening at a position corresponding to the p-type contact layer may be formed on the surface of the nitride semiconductor laser laminate structure.

[0028] The nitride-based semiconductor laser laminate structure has a plurality of waveguides extending in a direction perpendicular to the one direction, which is the longitudinal direction of the laser bar. Each of the plurality of waveguides functions as a current injection region and an optical waveguide in the laser element 10. This waveguide corresponds to the light emitting section 100 according to this embodiment. The plurality of waveguides corresponding to the plurality of light emitting sections 100 are parallel to each other and are formed at a predetermined pitch along the one direction.

[0029] The multiple waveguides are formed, for example, in a p-type cladding layer in a nitride-based semiconductor laser laminate structure. As an example, the multiple waveguides have a ridge stripe structure and are formed as multiple ridges in the p-type cladding layer. In this case, the p-type contact layer may be multiple semiconductor layers individually formed on each of the multiple ridges, or may be one semiconductor layer continuously formed to cover the multiple ridges.

[0030] Each of the multiple light-emitting units 100, which correspond to the multiple waveguides, emits a laser light. Specifically, the first light-emitting unit 101 emits the first laser light L1, and the second light-emitting unit 102 emits the second laser light L2. Similarly, the third light-emitting unit 103 to the 38th light-emitting unit 138 emit the third laser light L3 to the 38th laser light L38, respectively. Here, when it is not necessary to distinguish between the first laser light L1 to the 38th laser light L38, they will be referred to as laser light L100.

[0031] The p-side electrode is formed in contact with the upper side of the nitride semiconductor laser laminate structure. The p-side electrode is made of, for example, Ti, Pt, and Au. The p-side electrode is formed in contact with, for example, the upper side of the p-type contact layer of the nitride semiconductor laser laminate structure. A plurality of p-side electrodes are formed to correspond to the plurality of waveguides (ridge portions). That is, the p-side electrode is formed in a divided manner. The p-side electrode does not have to be divided into a plurality of electrodes. For example, the p-side electrode may be one electrode common to the plurality of waveguides.

[0032] The n-side electrode is formed on the second main surface of the substrate. The n-side electrode is made of, for example, Ti, Pt, and Au. In this embodiment, a plurality of n-side electrodes are formed to correspond to the plurality of waveguides (ridge portions). That is, the n-side electrode is formed in a divided manner. The n-side electrode does not have to be divided into a plurality of electrodes. For example, the n-side electrode may be a single electrode common to the plurality of waveguides.

[0033] The multiple light emitting sections 100 emit multiple laser beams L100 from one end face side in the short side direction of the laser element 10. In other words, this one end face is the light emitting face. The face opposite to the light emitting face and facing away from the light emitting face is the rear end face of the laser element 10. The rear end face is coated with an end face coating film as a reflective film.

[0034] Although not shown, a submount is provided on which the laser element 10 is mounted. The submount includes a base and an electrode layer laminated on the upper surface of the base.

[0035] The substrate is preferably made of a material having a high thermal conductivity and a small thermal expansion coefficient. The substrate 211 may be made of, for example, SiC ceramic, AlN ceramic, semi-insulating SiC crystal, or artificial diamond. The substrate may also be made of a metal material such as a Cu-W alloy or a Cu-Mo alloy. The electrode layer is made of, for example, Ti / Pt / Au in that order from the substrate side.

[0036] The laser element 10 is mounted on a submount via a bonding layer. In this embodiment, the laser element 10 is electrically connected to an electrode layer of the submount. Therefore, a metal bonding material such as AuSn solder is used as the bonding layer.

[0037] The plurality of laser beams L100 emitted from the plurality of light-emitting portions 100 of the laser element 10 configured in this manner are incident on the optical element 20.

[0038] The optical element 20 is an optical component that collects the multiple laser beams L100 emitted from the multiple light-emitting units 100. The optical element 20 is, for example, a collecting lens made of glass or transparent resin. An anti-reflection coating film for suppressing reflection of the multiple laser beams L100 may be provided on the surface of the optical element 20. The optical element 20 is, for example, a plano-convex collecting lens in which the surface on the multiple light-emitting units 100 side is a convex surface and the surface on the wavelength dispersion element 30 (described later) side is a flat surface.

[0039] 1, the multiple laser beams L100 emitted from the multiple light-emitting units 100 are parallel to each other. Since the optical element 20 is a plano-convex focusing lens, it can receive the multiple parallel laser beams L100 and further emit the multiple laser beams L100 so as to be focused toward the wavelength dispersion element 30.

[0040] The optical element 20 is not limited to this. The optical element 20 may be, for example, a plano-convex condenser lens in which the surface on the side of the multiple light emitting units 100 is a flat surface and the surface on the side of the wavelength dispersion element 30 is a convex surface. The optical element 20 may be a cylindrical lens extending in the longitudinal direction of the laser element 10, which is a laser bar. In addition, in the present embodiment, one optical element 20 is provided, but multiple optical elements having different shapes may be provided. When multiple optical elements are provided, for example, an optical element that collects the fast axes of the multiple laser beams L100 and an optical element that collects the slow axes of the multiple laser beams L100 may be provided. In addition, the optical element 20 may be a beam twister element. When the optical element 20 is a beam twister element, the optical element 20 has the effect of rotating the fast axis and the slow axis of the multiple laser beams L100 by 90 degrees.

[0041] In either case, the optical element 20 condenses the multiple laser beams L100. The multiple laser beams L100 condensed by the optical element 20 travel toward the wavelength dispersion element 30.

[0042] The wavelength dispersion element 30 is an optical component that receives the multiple laser beams L100 emitted from the optical element 20, and emits the multiple laser beams L100 toward a partial reflection mirror 40 (described later) by aligning their optical axes. In this embodiment, the multiple laser beams L100 collected by the optical element 20 are incident on one point on the surface of the wavelength dispersion element 30. The wavelength dispersion element 30 is, for example, a diffraction grating that diffracts each of the multiple laser beams L100. More specifically, the wavelength dispersion element 30 according to this embodiment is a blazed diffraction grating, but is not limited to this and may be, for example, a prism.

[0043] In this embodiment, the multiple laser beams L100 emitted from the optical element 20 are collected by the optical element 20 and are incident on one point on the surface of the wavelength dispersion element 30. At this time, as shown in Fig. 1, the multiple laser beams L100 are incident on the wavelength dispersion element 30 at different angles of incidence θi, where i is an integer from 1 to 38 and corresponds to each of the 38 light-emitting units 100. For example, the first laser beam L1 emitted from the first light-emitting unit 101 is incident on the wavelength dispersion element 30 at an angle of incidence θ1.

[0044] The multiple laser beams L100 emitted from the multiple light-emitting units 100 are diffracted by the wavelength dispersion element 30, and then pass through the wavelength dispersion element 30 and travel as diffracted light toward the partial reflection mirror 40. That is, in this embodiment, the wavelength dispersion element 30 is a transmissive diffraction grating. Note that the wavelength dispersion element 30 may be a reflective diffraction grating.

[0045] Furthermore, as shown in FIG. 1, the wavelength dispersion element 30 causes the optical axes of the diffracted light beams of the plurality of laser beams L100 to coincide with each other, that is, combines the diffracted light beams with each other, and outputs the combined light toward the partial reflection mirror 40.

[0046] The partial reflection mirror 40 is an optical component that reflects some of the multiple laser beams L100 emitted from the wavelength dispersion element 30 and transmits the other parts of the multiple laser beams L100 emitted from the wavelength dispersion element 30. The reflectance of the partial reflection mirror 40 has wavelength dependency, for example, in the wavelength region (purple to blue region) of the output light Lo. In this embodiment, the reflectance of the partial reflection mirror 40 is 5% to 25% in the wavelength region of the output light Lo. That is, the partial reflection mirror 40 is an optical component that reflects, for example, a part of the first laser beam L1 in accordance with the reflectance and transmits the first laser beam L1 that is not reflected (that is, the other parts of the first laser beam L1).

[0047] It should be noted that the range of the reflectance of the partial reflection mirror 40 is not limited to the above. Furthermore, the wavelength region in which the reflectance of the partial reflection mirror 40 has wavelength dependency is not limited to the above.

[0048] The partial reflection mirror 40 is composed of a dichroic mirror etc. More specifically, the partial reflection mirror 40 is composed of a transparent substrate made of glass, transparent resin or the like, and a dichroic layer made of a dielectric multilayer film or the like provided on the surface of the substrate.

[0049] The partial reflection mirror 40 can have a predetermined reflectance for a predetermined wavelength by controlling the material of the dielectric material constituting the dichroic layer and / or the configuration of the multilayer film, which allows the reflectance of the partial reflection mirror 40 to have wavelength dependency in the wavelength region of the output light Lo.

[0050] As described above, the partial reflection mirror 40 is incident on with a plurality of laser beams L100 whose optical axes are aligned.

[0051] The remaining part of the laser beams L100 transmitted through the partial reflection mirror 40 is output as output beam Lo. On the other hand, a part of the laser beams L100 is reflected by the partial reflection mirror 40 and enters the wavelength dispersion element 30 again. The wavelength dispersion element 30 separates the laser beams L100, each of which has its optical axis aligned, into a plurality of laser beams L100 for each wavelength. The wavelength dispersion element 30 emits the plurality of laser beams L100 separated for each wavelength toward the optical element 20. Furthermore, the optical element 20 emits each of the plurality of laser beams L100 separated for each wavelength toward each of the plurality of light-emitting units 100. That is, a part of the plurality of laser beams L100 emitted from the plurality of light-emitting units 100 is reflected by the partial reflection mirror 40 and returned to the plurality of light-emitting units 100. Furthermore, the multiple laser beams L100 incident on the multiple light emitting portions 100 are reflected by an end face coating film provided on the rear end face of the laser element 10 and directed toward the optical element 20.

[0052] To summarize the above, in this embodiment, an external cavity is formed between the rear end face of the laser element 10 and the partial reflection mirror 40. In other words, the laser element 10 is an external cavity laser element (ECLD: External Cavity Lasers Diode).

[0053] In such a laser light source device 1, as described above, the multiple laser beams L100 emitted from the multiple light emitting units 100 are incident on the wavelength dispersion element 30 at different incidence angles θi. Since the resonator lengths of the multiple laser beams L100 are different depending on the incidence angles θi, the multiple laser beams L100 have different oscillation wavelengths. Therefore, in this embodiment, the wavelength dispersion element 30 can be said to be an optical component that combines wavelengths. In addition, in the wavelength dispersion element 30, which is a diffraction grating, the diffraction grating shape, such as the pitch and blaze angle of the diffraction grooves, is determined so that the proportion of diffracted light that leaves the wavelength dispersion element 30 and heads toward the partial reflection mirror 40 is sufficiently larger than the diffracted light that heads toward other directions.

[0054] [Behavior of feedback light] Here, the light (hereinafter, returned light) that is reflected by the partial reflection mirror 40 and returns to each of the multiple light-emitting sections 100 out of the multiple laser lights L100 emitted from each of the multiple light-emitting sections 100 will be described using a laser light source device according to a comparative example.

[0055] The laser light source device according to the comparative example has the same components as the laser light source device 1 according to the present embodiment, except for the following one point: the reflectance of the partial reflection mirror provided in the laser light source device according to the comparative example does not have wavelength dependency in the wavelength region of the output light Lo, and is a constant value (e.g., 10%).

[0056] Next, the results of a simulation performed on a laser light source device according to a comparative example are shown. Fig. 2 is a diagram showing the results of a simulation of external feedback light amplitude and ASE (Amplified Spontaneous Emission) amplitude for multiple laser lights of a laser light source device according to a comparative example. In Fig. 2, the horizontal axis is the wavelength of the laser light, five sharp peaks represent the external feedback light amplitude, and one curve represents the ASE amplitude.

[0057] The simulation result shown in FIG. 2 is used to predict the behavior of a plurality of laser beams in a laser source device according to a comparative example.

[0058] Here, the ASE amplitude (amplified spontaneous emission amplitude) in Fig. 2 is an index representing the laser gain (i.e., ease of amplification) in multiple light-emitting units. Furthermore, the external feedback light amplitude in Fig. 2 is a value calculated from the ASE amplitude, and is an index representing the feedback light efficiency of each of the multiple light-emitting units. Note that the feedback light efficiency of a light-emitting unit indicates the degree of feedback light to that light-emitting unit. The higher the feedback light efficiency of a light-emitting unit, the more light is returned to that light-emitting unit as feedback light.

[0059] Moreover, λ5, λ4, λ3, λ2 and λ1 in FIG. 2 are peak wavelengths (hereinafter referred to as oscillation peak wavelengths) of the first laser light, the tenth laser light, the twentieth laser light, the thirtieth laser light and the thirty-eighth laser light in the comparative example, respectively.

[0060] As shown by the simulation results of the external feedback light amplitude in Fig. 2, in the comparative example, the feedback light efficiency increases in the order of the 1st light-emitting section, the 10th light-emitting section, the 20th light-emitting section, the 30th light-emitting section, and the 38th light-emitting section. In other words, in the laser light source according to the comparative example, there is variation in the feedback light efficiency of each of the multiple light-emitting sections. This variation occurs due to the influence of the diffraction efficiency of the wavelength dispersion element and the influence of multiple adjacent laser lights.

[0061] First, the effect of diffraction efficiency will be described.

[0062] The diffraction efficiency is the value obtained by dividing the energy of diffracted light by the energy of incident light. Specifically, the higher the diffraction efficiency, the greater the proportion of light that is emitted from the wavelength dispersion element as diffracted light out of the light that is incident on the wavelength dispersion element.

[0063] This diffraction efficiency is a value that changes depending on the incidence angle and oscillation wavelength of the multiple laser beams. In the comparative example, the incidence angle and oscillation wavelength of each of the multiple laser beams are different, so the diffraction efficiency for each of the multiple laser beams is different. In other words, there is variation in the diffraction efficiency for each of the multiple laser beams.

[0064] Also, as an example, in the comparative example, the lower the diffraction efficiency, the smaller the proportion of light that is combined and directed toward the partial reflection mirror among the light emitted from the optical element and incident on the wavelength dispersion element. In other words, the lower the diffraction efficiency, the more light that exhibits a behavior different from that of the multiple laser beams L100 shown by the arrows in FIG. 1. Since the light that exhibits such a different behavior does not return to the multiple light-emitting units again after being emitted from the multiple light-emitting units, the return light efficiency of each of the multiple light-emitting units becomes low. Note that the higher the diffraction efficiency, the opposite phenomenon to the above occurs.

[0065] That is, in the comparative example, since the diffraction efficiency depends on the incident angle and the oscillation wavelength, the diffraction efficiency for each of the plurality of laser beams varies, and as a result, the feedback light efficiency of each of the plurality of light emitting units varies.

[0066] Next, the influence of a plurality of adjacent laser beams will be described.

[0067] As an example of adjacent laser beams, a first laser beam emitted from a first light-emitting unit and a second laser beam emitted from a second light-emitting unit will be used for explanation. The first laser beam and the second laser beam affect each other in the optical element. For example, when the second laser beam leaks into the optical path of the first laser beam, the second laser beam affects the first laser beam. Similarly, when the first laser beam leaks into the optical path of the second laser beam, the first laser beam affects the second laser beam. Due to these influences, the respective return light efficiencies of the first light-emitting unit that emits the first laser beam and the second light-emitting unit that emits the second laser beam change. Therefore, there is variation in the respective return light efficiencies of the multiple light-emitting units including the first light-emitting unit and the second light-emitting unit.

[0068] In the laser light source device according to the comparative example, such variation in feedback light efficiency occurs, and problems such as a decrease in oscillation stability occur in the multiple laser lights. Similarly, in the laser light source device 1 according to the present embodiment, the feedback light efficiency is affected by the diffraction efficiency of the wavelength dispersion element 30 and by the multiple adjacent laser lights L100.

[0069] However, unlike the partial reflection mirror according to the comparative example, the partial reflection mirror 40 of the laser light source device 1 according to the present embodiment has wavelength dependency. The effect of the partial reflection mirror 40 having wavelength dependency will be described below.

[0070] Fig. 3 is a diagram showing the reflection spectra of partial reflecting mirror 40 according to the present embodiment and a partial reflecting mirror according to a comparative example. In Fig. 3, the solid line indicates the reflectance of partial reflecting mirror 40 according to the present embodiment, and the dashed line indicates the reflectance of the partial reflecting mirror according to the comparative example.

[0071] As described above, the reflectance of the partial reflection mirror 40 according to the present embodiment has wavelength dependency, while the reflectance of the partial reflection mirror according to the comparative example does not have wavelength dependency and is a constant value (10%). Note that λ5, λ4, λ3, λ2, and λ1 in Fig. 3 are the oscillation peak wavelengths of the 1st laser light, the 10th laser light, the 20th laser light, the 30th laser light, and the 38th laser light in the present embodiment and the comparative example, respectively.

[0072] Here, the higher the reflectance in a predetermined wavelength region, the more the laser light L100 having an oscillation peak wavelength in the predetermined wavelength region is reflected, and therefore the feedback light efficiency of the light-emitting unit 100 that emits such laser light L100 is increased. Since the reflectance of the partial reflection mirror 40 has wavelength dependency, it becomes possible to control the feedback light efficiency of each of the multiple light-emitting units 100 by controlling the reflectance in a predetermined wavelength region.

[0073] Furthermore, in this embodiment, the reflectance of the partial reflection mirror 40 has wavelength dependency such that the feedback light efficiency of each of the multiple light-emitting units 100 is equal. The reflectance of the partial reflection mirror 40 is determined based on the feedback light efficiency of the light-emitting units under conditions in which the reflectance of the partial reflection mirror is assumed to be constant, for example, as in the comparative example.

[0074] It is determined that the lower the feedback light efficiency of a predetermined light-emitting unit under the above conditions, the higher the reflectance of the partial reflection mirror 40 in the wavelength region including the oscillation peak wavelength of the laser light emitted from the predetermined light-emitting unit. In other words, there is a negative correlation between the feedback light efficiency of a predetermined light-emitting unit under the above conditions and the reflectance of the partial reflection mirror 40 in the above wavelength region.

[0075] Specifically, as shown in FIG. 2, the feedback light efficiency of the light emitting section under the above conditions (i.e., the comparative example) is 2 , λ 3 , λ 4 and λ 5 3, the reflectance of the partial reflection mirror 40 is lower in the order of the light emitting portion emitting the laser beam λ1, λ2, λ3, λ4, λ5, λ6, λ7, λ8, λ9, λ10, λ11, λ12, λ13, λ14, λ15, λ16, λ17, λ18, λ19, λ11, λ111, 2 , λ 3 , λ4 and λ 5 Since the feedback light efficiency of each of the plurality of light-emitting sections 100 increases as the reflectance of the partial reflection mirror 40 increases, the feedback light efficiency of each of the plurality of light-emitting sections 100 tends to become equal.

[0076] That is, in this embodiment, the reflectance of the partial reflection mirror 40 has the above configuration, and thus, for example, a laser light source device 1 is realized in which the feedback light efficiency of each of the multiple light-emitting units 100 is equal compared to the comparative example. Also, it can be said that the partial reflection mirror 40 has the above reflectance, and thus the variation in the feedback light efficiency of each of the multiple light-emitting units 100 is corrected to be suppressed compared to the comparative example. As a result, the decrease in the oscillation stability of the multiple laser beams L100 is suppressed.

[0077] Note that "having equal feedback light efficiency" does not necessarily mean that the efficiency is completely the same. For example, if the feedback light efficiency of each of the light-emitting sections 100 is within a range of 90% to 110% of the average value calculated from the feedback light efficiency of each of the light-emitting sections 100, the feedback light efficiency can be considered to be equal.

[0078] In this embodiment, the wavelength dispersion element 30 is a diffraction grating.

[0079] As a result, the wavelength dispersion element 30 has higher diffraction efficiency, and therefore the light utilization efficiency of the laser light source device 1 can be improved.

[0080] In the present embodiment, the laser source device 1 includes a laser element 10 having a plurality of light-emitting sections 100 (for example, a first light-emitting section 101 and a second light-emitting section 102).

[0081] This makes it possible to equalize the feedback light efficiency of each of the multiple light emitting sections 100 in the laser light source device 1 including the laser element 10 having a multi-emitter structure.

[0082] The reflectance of the partial reflection mirror 40 is preferably 3% to 50%, more preferably 5% to 40%, and even more preferably 8 to 30%. The higher the reflectance, the higher the feedback light efficiency. Also, the lower the reflectance (i.e., the higher the transmittance), the more the amount of output light Lo increases, improving the light utilization efficiency of the laser light source device 1.

[0083] Here, a laser processing device, which is one application example of the laser source device 1, will be described with reference to FIG.

[0084] 4 is a schematic diagram showing a laser processing apparatus 300 according to the present embodiment. The laser processing apparatus 300 is an apparatus including a laser source device 1, an optical path 500, and a head 600.

[0085] The laser light source device 1 is configured as described above, but for the sake of simplicity, the optical element 20, the wavelength dispersion element 30 and the partial reflection mirror 40 are collectively illustrated as an optical member 400 in FIG.

[0086] The optical path 500 is an optical component that receives the output light Lo output from the laser light source device 1 and outputs the output light Lo to the head 600. The optical path 500 is composed of optical components such as optical fibers and reflecting mirrors.

[0087] The head 600 is an optical component that outputs the output light Lo output from the laser source device 1 via the optical path 500 as processing light L for the laser processing device 300. The head 600 may include an optical element such as a lens having a light collecting effect.

[0088] The laser processing apparatus 300 having such a configuration can irradiate the plurality of laser beams L100 emitted from the laser element 10 directly to the workpiece at a high light density. Furthermore, since the plurality of laser beams L100 emitted from the laser element 10 can be directly used, the wavelength of the laser beam to be used can be easily changed by changing the laser element 10. Therefore, it is possible to select a wavelength that matches the light absorption rate of the workpiece, and it is possible to improve the efficiency of processing such as welding or cutting.

[0089] (Embodiment 2) Next, a laser light source device according to a second embodiment will be described with reference to Fig. 5. Fig. 5 is a perspective view showing the configuration of a plurality of laser elements included in the laser light source device according to the present embodiment.

[0090] This embodiment differs from the first embodiment in that a plurality of laser elements are provided.

[0091] Specifically, the laser light source device according to the present embodiment has the same configuration as the laser light source device 1 according to the first embodiment, except that the laser light source device according to the present embodiment includes a laser element 10a and a laser element 10b as the multiple laser elements.

[0092] Each of the laser element 10a and the laser element 10b has the same configuration as the laser element 10 according to the first embodiment.

[0093] The laser element 10a has a plurality of light-emitting sections 100a, each of which is made up of 38 light-emitting sections 100a including the first light-emitting section 101a to the 38th light-emitting section 138a. Each of the light-emitting sections 100a emits a laser beam. Here, the laser beams emitted by each of the light-emitting sections 100a are collectively referred to as a plurality of laser beams L100a.

[0094] Similarly, the laser element 10b has a plurality of light-emitting sections 100b each consisting of 38 light-emitting sections 100b including the first light-emitting section 101b to the 38th light-emitting section 138b. Each of the light-emitting sections 100b emits a laser beam. Here, the laser beams emitted by each of the light-emitting sections 100b are collectively referred to as a plurality of laser beams L100b.

[0095] The reflectance of the partial reflection mirror according to this embodiment has wavelength dependency such that the feedback light efficiency of each of the plurality of light emitting sections 100a and the feedback light efficiency of each of the plurality of light emitting sections 100b are equal.

[0096] In other words, the reflectance of the partial reflection mirror according to this embodiment has wavelength dependency such that the return light efficiency of each of the 76 light-emitting units, a total of the first light-emitting unit 101a to the 38th light-emitting unit 138a and the first light-emitting unit 101b to the 38th light-emitting unit 138b, is equal. The reflectance of the partial reflection mirror according to this embodiment has wavelength dependency such that the return light efficiency of each of the first light-emitting unit 101a and the second light-emitting unit 102b is equal, as an example.

[0097] Even in this case, a laser light source device in which the feedback light efficiency of each of the multiple light-emitting sections 100a and the feedback light efficiency of each of the multiple light-emitting sections 100b are equal is realized, and deterioration in the oscillation stability of the multiple laser beams L100a and L100b is suppressed.

[0098] (Embodiment 3) Next, a laser light source device according to a third embodiment will be described with reference to Fig. 6. Fig. 6 is a perspective view showing the configuration of a plurality of laser elements 10c included in the laser light source device according to the present embodiment.

[0099] This embodiment differs from the first and second embodiments in that each of the multiple laser elements 10c has one light emitting portion.

[0100] Specifically, the laser light source device of this embodiment has the same configuration as the laser light source devices of embodiments 1 and 2, except that it includes a plurality of laser elements 10c and each of the plurality of laser elements 10c has one light-emitting portion.

[0101] In this embodiment, the multiple laser elements 10c are configured by the first laser element 1c to the 38th laser element 38c. The first laser element 1c to the 38th laser element 38c have the first light emitting portion 101c to the 38th light emitting portion 138c, respectively. That is, each of the multiple laser elements 10c according to this embodiment is a laser chip having a single emitter structure. Also, each of the multiple light emitting portions (the first light emitting portion 101c to the 38th light emitting portion 138c) emits a laser beam. Here, the laser beams emitted by each of the multiple light emitting portions are collectively referred to as multiple laser beams L100c.

[0102] In this embodiment as well, the reflectance of the partial reflection mirror has wavelength dependency such that the feedback light efficiency of each of the plurality of light-emitting units (i.e., the first light-emitting unit 101c to the 38th light-emitting unit 138c) is equal. In this case as well, a laser light source device in which the feedback light efficiency of each of the plurality of light-emitting units is equal is realized, and deterioration of the oscillation stability of the plurality of laser beams L100c is suppressed.

[0103] In this embodiment, the laser light source device Place The laser element 10c includes, for example, a first laser element 1c having a first light emitting portion 101c and a second laser element 2c having a second light emitting portion 102c.

[0104] This makes it possible to equalize the feedback light efficiency of each of the multiple light emitting sections in a laser light source device including the laser element 10c having a single emitter structure.

[0105] (Other embodiments) While the laser source device and the laser processing device according to the present disclosure have been described above based on the embodiments, the present disclosure is not limited to the above-described embodiments.

[0106] In the above embodiment, the waveguide in the laser element has a ridge stripe structure, but is not limited thereto. For example, the waveguide may have an electrode stripe structure composed of divided electrodes only without forming a ridge stripe, or may have a current confinement structure using a current blocking layer.

[0107] In addition, in the laser element in the above embodiment, the case where a nitride-based semiconductor material is used is exemplified, but the present invention is not limited to this. For example, the present invention can be applied to a case where a semiconductor material other than a nitride-based semiconductor material is used. In this case, the laser element has a semiconductor laser laminate structure using another semiconductor material, rather than a nitride-based semiconductor laser laminate structure.

[0108] In addition, the present disclosure also includes forms obtained by applying various modifications to the embodiments that a person skilled in the art may conceive, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the spirit of the present disclosure. [Industrial Applicability]

[0109] The laser source device and the laser processing device disclosed herein are useful as industrial machines used for processing such as welding or cutting. [Explanation of symbols]

[0110] 1 Laser light source device 1c First laser element 2c Second laser element 3c Third laser element 10, 10a, 10b, 10c Laser element 20 Optical Elements 30 Wavelength dispersion element 37c 37th laser element 38c 38th laser element 40 Partially Reflecting Mirror 100, 100a, 100b Light emitting part 101, 101a, 101b, 101c First light emitting unit 102, 102a, 102b, 102c Second light emitting unit 103, 103a, 103b, 103c Third light emitting unit 137, 137a, 137b, 137c 37th light-emitting part 138, 138a, 138b, 138c 38th light-emitting part 300 Laser processing equipment 400 Optical Components 500 light path 600 Head L1 First laser beam L2 Second laser beam L3 Third laser beam L37 37th laser beam L38 38th laser beam L100, L100a, L100b, L100c laser light L processing light Lo output light θi incident angle

Claims

1. a first light emitting unit that emits a first laser beam; a second light emitting unit that emits a second laser light; an optical element that focuses the first laser light and the second laser light; a wavelength dispersion element into which the first laser light and the second laser light emitted from the optical element are incident and which outputs the first laser light and the second laser light with their optical axes aligned with each other; a partial reflection mirror that reflects and returns a portion of the first laser light emitted from the wavelength dispersion element and a portion of the second laser light emitted from the wavelength dispersion element, and transmits another portion of the first laser light emitted from the wavelength dispersion element and another portion of the second laser light emitted from the wavelength dispersion element, The reflectance of the partial reflection mirror has wavelength dependency, The reflectance has a wavelength dependency such that the first light emitting section and the second light emitting section have equal return light efficiencies. Laser light source device.

2. The wavelength dispersion element is a diffraction grating.

2. The laser light source device according to claim 1.

3. A laser element having the first light emitting portion and the second light emitting portion is provided.

3. The laser light source device according to claim 1 or 2.

4. a first laser element having the first light emitting portion; a second laser element having the second light emitting portion; 3. The laser light source device according to claim 1 or 2.

5. The laser light source device according to any one of claims 1 to 4 is provided. Laser processing equipment.

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