laser device

Abstract

To provide a laser device capable of improving fiber coupling efficiency while reducing the size.SOLUTION: A laser device 1 combines laser beams LB1, LB2, and LB3 emitted from multiple first to third laser light sources R1, R2, and R3 and injects the same into one output optical fiber F. The light source optical fibers F1, F2, and F3 of the first to third laser light sources R1 to R3 are arranged parallel to each other in a three-dimensional space. The laser device is configured so that the optical axes of the parallel laser beams LB1, LB2, and LB3 emitted from the light source optical fibers F1, F2, and F3 are aligned with the axis of output optical fiber F via collimators 2, 3, 4, reflecting mirrors 8, 9, prism mirrors 5, 6, and condensing lens 7.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laser device equipped with a beam-combining optical system for combining (combining) laser beams emitted from a plurality of laser light sources and inputting the combined laser beams into a single output optical fiber. [Background technology]

[0002] For example, high-power laser devices used for product processing (laser processing) and soldering of components on circuit boards use laser multiplexers (optical power combining systems) that combine laser beams emitted from multiple laser light sources or multiple optical fibers and input them into a single optical fiber (multimode optical fiber). Various proposals have been made regarding such laser multiplexers.

[0003] For example, Patent Document 1 proposes a laser combining device that includes multiple laser light sources arranged on the same plane, an optical fiber that receives the laser beams emitted from each laser light source, and multiple lenses that focus the multiple laser beams and combine them onto the incident end face of a single optical fiber.

[0004] Furthermore, Patent Document 2 proposes a laser combining device in which a first light-emitting element and a second light-emitting element serving as light sources are arranged perpendicular to each other in a housing, and the laser beams emitted from these first light-emitting element and second light-emitting element are made incident on a single optical fiber via a half mirror.

[0005] However, the laser multiplexing device proposed in Patent Document 1 has a problem in that the laser beam is obliquely incident on the optical fiber with a large incident angle, resulting in large optical loss and reduced fiber coupling efficiency.

[0006] Furthermore, the laser multiplexing device proposed in Patent Document 2 has the problem that the coupling efficiency is reduced due to optical loss caused by the half mirror, and the device becomes large because the light sources are arranged in directions bent by 90 degrees from each other.

[0007] Therefore, Patent Document 3 proposes a laser combining device in which multiple laser light sources are arranged so that the optical axes of the emitted light from the laser light sources are inclined relative to the normal to the incident surface of the optical fiber, and a prism (optical component) is arranged between the laser light sources and the optical fiber, and the angle between the optical axis of the emitted light from the exit surface of this prism and the normal to the incident surface of the optical fiber (incidence angle into the optical fiber) is set to be smaller than the incident light inclination angle between the optical axis of the emitted light from each laser light source at the incident surface of the prism and the normal to the incident surface of the optical fiber. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-248581 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-045092 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-064537 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the laser multiplexing device proposed in Patent Document 3, multiple laser light sources are arranged in a two-dimensional plane at an angle inclined with respect to the normal to the incident surface of the optical fiber, which poses a problem that the installation space for these laser light sources becomes large and the device becomes large in size.

[0010] However, when an adjustment mechanism is provided to adjust the angle and position of optical elements such as lenses used in a laser multiplexing device, problems arise in that the fiber coupling efficiency decreases due to heat generation at high output, vibrations during transportation, and a lack of long-term stability resulting from the structure of the adjustment mechanism.

[0011] The present invention has been made in view of the above problems, and has as its object to provide a laser device that can improve fiber coupling efficiency and achieve miniaturization. [Means for solving the problem]

[0012] The laser device according to the present invention comprises: First and second laser beams are respectively emitted. and third a laser light source; an output optical fiber having an axis and configured to output laser light from the laser device to the outside; The first and second and third a multiplexing optical system that multiplexes laser light coming from laser light sources and makes the multiplexed laser light enter the output optical fiber, The combining optical system includes: The first and second and third The first and second laser beams are converted into parallel beams by the laser light source. and third A collimator; The laser light coming from the second collimator is collimated to the axis. In a parallel direction Inducing Surface a first prism mirror having a surface for guiding the laser light coming from the third collimator in a direction parallel to the axis; a guidance optical system having The first Collimator Arriving from Parallel to the axis laser light and the second and after being converted into parallel light by the third collimator, it is guided in a direction parallel to the axis by the guidance optical system and arrives. do each Laser light and 、 a focusing optical system for focusing light onto the output optical fiber; It is something that the guiding optical system guides the laser light coming from the second and third collimators so that a straight line connecting an optical axis of the laser light coming from the first collimator and an optical axis of each laser light that has been converted into parallel light by the second and third collimators and then guided by the guiding optical system forms an equilateral triangle, and so that the centroid of the equilateral triangle coincides with the axis center, Each of the first and second prism mirrors has a flat top surface facing the laser light coming from the first collimator, and the angle formed by the top surfaces of the first and second prism mirrors on the sides facing the laser light coming from the first collimator is set to 120°. It is characterized by: [Effects of the Invention]

[0013] According to the present invention, The laser beams emitted from the three laser light sources and combined by the combining optical system are efficiently incident on the axis of the output optical fiber, further improving fiber coupling efficiency. Also, the laser beam emitted from the first laser light source can travel straight through the space sandwiched between the inclined surfaces of the two prism mirrors at an angle of 120° without interfering with the two prism mirrors. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic plan view showing a basic configuration of a laser device according to an embodiment of the present invention. [Figure 2]1 is a perspective view showing a basic configuration of a laser device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a plan view of a base of the laser device according to the embodiment of the present invention. [Figure 4] FIG. 4 is a view taken in the direction of arrow A in FIG. 3. [Figure 5] 1A is a diagram showing a prism mirror, in which (a) is a plan view, (b) is a front view (viewed in the direction of arrow B in (a)), and (c) is a side view (viewed in the direction of arrow C in (a)). [Figure 6] FIG. 2 is a perspective view of an output portion of a laser device according to an embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view taken along line DD in FIG. 6. [Figure 8] 1A and 1B are schematic plan views showing a method for adjusting misalignment of an optical axis in a laser device according to an embodiment of the present invention. [Figure 9] 10A and 10B are schematic plan views illustrating a method for suppressing the occurrence of vignetting in a laser device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0016] FIG. 1 is a block diagram showing the basic configuration of a laser device according to an embodiment of the present invention, FIG. 2 is a perspective view showing the basic configuration of the laser device, FIG. 3 is a plan view of the base of the laser device, and FIG. 4 is a view in the direction of arrow A in FIG. 3.

[0017] 1, the laser device 1 according to this embodiment includes first to third laser light sources R1, R2, and R3 that emit laser beams LB1, LB2, and LB3, respectively, a combining optical system CW that combines the laser beams LB1, LB2, and LB3 emitted from the first to third laser light sources R1 to R3, and one output optical fiber F into which the laser beam LB combined by the combining optical system CW is incident. In the following description, the directions indicated by arrows in FIGS. 1 and 2 are referred to as the "X-axis direction," the "Y-axis direction," and the "Z-axis direction," which are orthogonal to each other.

[0018] The first to third laser light sources R1, R2, and R3 are each composed of a laser element (LD) (not shown), a shaping optical system (not shown) that shapes the laser beams LB1, LB2, and LB3 emitted from the laser element, respectively, and light-source optical fibers F1, F2, and F3 provided downstream of each shaping optical system. The three light-source fibers F1 to F3 are arranged along the X-axis (front-rear direction) at equal intervals in the Y-axis (width direction). However, the central optical fiber F1 in the Y-axis direction is offset by Δh (shown in FIG. 4) in the Z-axis (height direction) from the two light-source optical fibers F2 and F3 located on either side of it (top and bottom in FIG. 1). In this way, the laser element (not shown) and the three light-source optical fibers F1 to F3 are arranged parallel to one another in three-dimensional space. Here, the three light source optical fibers F1 to F3 are capable of propagating laser beams LB1 to LB3 with a central wavelength of 450 nm and an output of 600 W, and have a diameter of φ200 μm and a numerical aperture NA of 0.2.

[0019] Although not shown, the light source optical fibers F1 to F3 have a double structure consisting of a core and a cladding that covers the outside of this core, and the core and cladding are made of quartz glass, which has high light transmittance. The single output optical fiber F, into which the single combined laser beam LB is incident, is also constructed in the same manner, but in this embodiment, this output optical fiber F is made of a multimode optical fiber.

[0020] The multiplexing optical system CW multiplexes the laser beams LB1, LB2, and LB3 emitted from the first to third laser light sources and inputs them into the output optical fiber F, and is composed of first to third collimators 2, 3, and 4, a prism mirror 5 that constitutes the first guiding optical system, a prism mirror 6 that constitutes the second guiding optical system, and a focusing lens 7 that constitutes the focusing optical system.

[0021] The first to third collimators 2, 3, and 4 are optical fibers F1 to F4 for light sources, respectively. F1 and 2, the collimators 2-3 are disposed in front (to the right in FIG. 1) of the light emission direction (X-axis direction) of each of the light source optical fibers F1-F3. Specifically, each of the collimators 2-3 is disposed at a position spaced apart from the emission end face of each of the light source optical fibers F1-F3 by the focal length f1 of the collimators 2-4.

[0022] The multiplexing optical system CW multiplexes the laser beams LB1, LB2, and LB3 emitted from the first to third laser light sources and inputs them into the output optical fiber F, and is composed of first to third collimators 2, 3, and 4, a prism mirror 5 that constitutes the first guiding optical system, a prism mirror 6 that constitutes the second guiding optical system, reflecting mirrors 8 and 9 that constitute the reflecting optical system, and a focusing lens 7 that constitutes the focusing optical system.

[0023] Here, the first to third collimators 2, 3, 4 convert the laser beams LB1, LB2, LB3 emitted from the first to third laser light sources R1, R2, R3, respectively, into parallel beams L1, L2, L3, and are respectively arranged at the rear of the light source optical fibers F1, F2, F3 (rear in the direction of emission of the laser beams LB1, LB2, LB3). 4 are arranged at positions spaced apart from the exit end faces of the light source optical fibers F1 to F3 by the focal length f1 of the collimators 2 to 4.

[0024] 1, the axis of the light-source optical fiber F1 located at the center in the width direction (Y-axis direction) and the axis of the output optical fiber F into which one combined laser beam LB is incident coincide in a planar view. In other words, the light-source optical fiber F1 located at the center in the width direction and the output optical fiber F are coaxially arranged in a planar view. As shown in FIG. 1, two block-shaped prism mirrors 5 and 6 are arranged spaced apart in the X-axis direction on the optical path of the collimated light L1 that is emitted from the light-source optical fiber F1 located at the center in the width direction and collimated by the collimator 2, and in front of the collimator 2 in the light emission direction (X-axis direction) (to the right in FIGS. 1 and 2).

[0025] Furthermore, a light-transmitting condenser lens 7 is disposed on the axial center of the light source optical fiber F1 and the output optical fiber F, which are arranged coaxially in a plan view, and between the prism mirrors 5, 6 and the output optical fiber F. This condenser lens 7 is used to condense parallel light beams L1 to L3 obtained by collimating the laser beams LB1 to LB3 emitted from the light source optical fibers F1 to F3 by the collimators 2 to 4, respectively, onto the center of the incident surface (axis center of the core) of the output optical fiber F. The distance between the condenser lens 7 and the incident end face of the output optical fiber F is set to the focal length f2 of the condenser lens 7.

[0026] On the other hand, on the optical paths of the parallel lights L2, L3 emitted from the light source optical fibers F2, F3 arranged on both sides (top and bottom in Figure 1) of the central light source optical fiber 1 in the Y-axis direction (width direction) and collimated by the collimators 3, 4, and further forward in the light emission direction (to the right in Figure 1) than the collimators 3, 4, reflection mirrors 8, 9 that reflect the parallel lights L2, L3 toward the prism mirrors 5, 6 are arranged at an angle of 45° in a plan view.

[0027] The detailed configuration of the prism mirror 5 will now be described with reference to Fig. 5. Since the two prism mirrors 5 and 6 have the same basic configuration, the configuration of only one of the prism mirrors, 5, will be described below.

[0028] FIG. 5 shows a prism mirror, with (a) being a plan view, (b) being a front view (viewed in the direction of arrow B in (a)), and (c) being a side view (viewed in the direction of arrow C in (a)). The prism mirror 5 shown in the figure is made of quartz glass, which has a high light transmittance and a low thermal expansion coefficient, and is shaped like a rectangular block. As shown in FIG. 2, this prism mirror 5 is fixed to a rectangular flat base 10 together with a reflecting mirror 8, and one of its side surfaces forms a reflecting surface 5a that is cut at an angle of 45° in plan view (see FIG. 5(a)). The reflecting surface 5a is coated with an HR coating.

[0029] As shown in FIG. 5(b), the top surface of the prism mirror 5 forms an inclined surface that is inclined at an angle of 60° with respect to the vertical plane, and this top surface 5b is provided with a reflective coating.

[0030] As shown in FIG. 4, the two prism mirrors 5 and 6 are positioned by fitting into rectangular grooves 10a and 10b of different depths formed in a stepped manner on the upper surface of the base 10. As shown in FIG. 3, the perpendicularity and parallelism of these prism mirrors 5 and 6 with respect to the three reference planes S1, S2, and S3 shown in FIG. 3 are 0.05° and 0.05°, respectively. mm The following settings are made and fixed by leaf springs (not shown).

[0031] Here, the reflecting surface 5a of the prism mirror 5 forms an inclined surface that is inclined at an angle of 45° in a plan view, so the collimated light L2 forms an elliptical light image on this reflecting surface 5a. The length of the major axis of this elliptical light image is √2 times (1.42 times) the diameter of the collimated light beam L2, so the length M of the reflecting surface 5a (see FIG. 5(a)) must be 1.5 times or more the diameter d of the collimated light L2 (see FIG. 1) (M≧1.5d). Note that, although not shown, the same applies to the other prism mirror 6.

[0032] When the two prism mirrors 5, 6 installed on the base 10 are viewed from the X-axis direction, as shown in FIG. 4, the two prism mirrors 5, 6 are arranged so that their side surfaces 5d, 6d are aligned on the same vertical plane. However, the angle between the inclined top surfaces 5b, 6b of the prism mirrors 5, 6 is set to 120° (a range that includes exactly 120° and covers deviations due to tolerances), as shown in the figure. Therefore, a V-shaped space is formed between the top surfaces 5b, 6b of the prism mirrors 5, 6 when viewed from the X-axis direction. The collimated light L1 emitted from the light-source optical fiber F1 located at the center in the width direction and collimated by the collimator 2 passes through this space. Note that, as shown in FIG. 3, the side surfaces 5d, 6d of the prism mirrors 5, 6 form a plane extending in the optical axis direction of the laser light LB1 emitted from the first light source R1 (light-source optical fiber F1) located at the center in the width direction.

[0033] As shown in Figure 4, the centroid G of an equilateral triangle connecting the optical axis O1 of the collimated light L1 emitted from the light-source optical fiber F1 located in the center in the width direction and collimated by the collimator 2, and the optical axes O2 and O3 of the collimated light L2 and L3 emitted from the light-source optical fibers F2 and F3 located on both sides of the central light-source optical fiber F1 in the width direction, respectively, collimated by the collimators 3 and 4, and reflected by the reflecting mirrors 8 and 9 and the prism mirrors 5 and 6, coincides with the axis of the output optical fiber F.

[0034] Here, the configuration of the output section of the laser device 1 according to this embodiment will be described below with reference to FIGS.

[0035] Fig. 6 is a cross-sectional perspective view of the output portion of a laser device according to an embodiment of the present invention, and Fig. 7 is a cross-sectional view taken along line DD in Fig. 6. A rectangular plate-shaped collimator base 21 is attached to the outer surface of a housing 20, which houses a base 10 (see Figs. 2 and 3), so that its position can be adjusted in the Y and Z axes (left and right and up and down directions). A cylindrical portion 21A is integrally formed on the inner surface of the collimator base 21 and is fitted into a circular hole 20a (see Fig. 7) opening into the side wall of the housing 20. A fiber receptacle 22 is attached to the outer surface of the collimator base 21. A metal fiber connector 23 is inserted and fixed into the fiber receptacle 22, and an output optical fiber F having a diameter of φ400 μm and a numerical aperture NA of 0.2 is inserted into the axis of the fiber connector 23.

[0036] 7, a cylindrical lens holder 24 that holds the condenser lens 7 is accommodated within the housing 20, and the position of the lens holder 24 is adjustable in the X, Y, and Z axis directions (up and down, left and right, and front and back directions). The lens holder 24 is connected to the cylindrical portion 21A of the collimator base 21 by a connecting ring 25 provided on the outer periphery thereof.

[0037] The above has described the configuration of the output section of the laser device 1 according to this embodiment, but the mounting structure of the three light source optical fibers F1 to F3 and the holding structure of the collimators 2 to 4 in the input section are the same as those in the output section, and therefore illustrations and descriptions thereof will be omitted.

[0038] Next, the operation of the laser device 1 configured as above will be described.

[0039] Laser beams LB1 to LB3 emitted from the laser elements of the three laser light sources R1, R2, and R3 propagate through three light-source optical fibers F1 to F3, respectively, and as shown in Fig. 1, when the laser beams LB1 to LB3 are emitted from the light-source optical fibers F1 to F3, the laser beams LB1 to LB3 are collimated into parallel beams L1 to L3 by passing through collimators 2 to 4, respectively. Here, the parallel beam L1 collimated by the collimator 2 disposed in the center in the width direction travels straight and passes through a focusing lens 7, where it is focused on the axis of the incident end face of one output optical fiber F.

[0040] Of the two collimators 3, 4 arranged on both sides of the central collimator 2, the collimated light L2 is transmitted through one of the collimators 3 (the upper one in FIG. 1) and is then reflected by the reflecting mirror 8, where its traveling direction is bent at a right angle and directed along the Y-axis direction toward the prism mirror 5. The collimated light L2 is then reflected by the reflecting surface 5a of the prism mirror 5, where its traveling direction is bent at a right angle and directed along the X-axis direction toward the condenser lens 7, and is then transmitted through the condenser lens 7 to be focused onto the axis of the incident end face of one output optical fiber F.

[0041] The parallel light L3, which is transmitted through the collimator 4 arranged on the other side (the lower side of FIG. 1) and is collimated, is reflected by the reflecting mirror 9, and its traveling direction is bent at a right angle, and it travels along the Y-axis direction toward the prism mirror 6. Then, this parallel light L3 is reflected by the reflecting surface 6a of the prism mirror 6, and its Direction of travel is bent at a right angle and directed along the X-axis to the condenser lens 7 , and is then transmitted through the condenser lens 7 to be condensed onto the axis of the incident end face of one output optical fiber F.

[0042] As described above, in the laser device 1 according to this embodiment, a total of three laser beams LB1 to LB3 emitted from the three light source optical fibers F1 to F3, respectively, are finally combined (combined) into one laser beam LB by the condenser lens 7 and focused onto the axis of the incident end face of one output optical fiber F. The laser beams are then incident from the incident end face of this output optical fiber F into the output optical fiber F and propagate within the core while being totally reflected. Then, the single laser beam LB, which has been made more powerful by combining, is emitted from the exit face of the output optical fiber F and is used for laser processing or the like.

[0043] As described above, in the laser device 1 according to this embodiment, the three light source optical fibers F1 to F3 are arranged parallel to each other in a three-dimensional space, so that the installation space required for these light source optical fibers F1 to F3 is small, and the laser device 1 can be made smaller.

[0044] 4, the centroid G of an equilateral triangle connecting light O1 of the collimated light L1 emitted from the light-source optical fiber F1 arranged at the center in the width direction and collimated by the collimator 2, and optical axes O2 and O3 of the collimated light L2 and L3 emitted from the light-source optical fibers F2 and F3 arranged on both sides of the central light-source optical fiber F1 and collimated by the collimators 3 and 4, respectively, and focused toward the center in the width direction by the reflecting mirrors 8 and 9 and the prism mirrors 5 and 6, respectively, is made to coincide with the axial center O of the output optical fiber F. Therefore, the collimated light L1 to L3 are multiplexed by the focusing lens 7, and efficiently enter the axial center O of the output optical fiber F with minimal loss. This increases the fiber coupling efficiency in the laser device 1 according to this embodiment.

[0045] 7, the output optical fiber F on the output side is attached to the metal housing 10 using a highly rigid metal fiber connector 23, and the three light source optical fibers F1 to F3 on the input side are also attached to the metal housing 10 using metal fiber connectors (not shown), so there is no problem of a decrease in fiber coupling efficiency due to heat generation at high output, vibration during transportation, lack of long-term stability due to the structure of the adjustment mechanism, etc. For example, even when a load of several N was applied to the fiber connector 23 or the output optical fiber F connected thereto, there was no change in the fiber coupling efficiency.

[0046] In this embodiment, the collimator base 21 and the lens holder 24 are provided with position adjustment mechanisms. However, when it is necessary to perform position adjustment with a precision higher than that of these position adjustment mechanisms, as shown in FIG. 8, for example, a parallel plate 13 may be placed between the collimator 3 and the reflecting mirror 8 on the optical path of the parallel light L2, and the parallel plate 13 may be used to correct the positional deviation in the direction perpendicular to the optical axis.

[0047] 8, for example, if the optical axis of the parallel light L3 collimated by the collimator 4 is misaligned, an inclined plate 14 can be placed between the collimator 4 and the reflecting mirror 9 on the optical path of the parallel light L3, and the misalignment of the optical axis can be adjusted by the inclined plate 14. Note that the parallel plate 13 and the inclined plate 14 are preferably thick and have a high refractive index within a range that ensures sufficient light transmittance.

[0048] Furthermore, in order to minimize vignetting caused by the prism mirror 6, it is desirable to intentionally misalign the optical axes of the output optical fiber F1 and the collimator 2, as shown in Fig. 9. In this case, it is also possible to fix the light source optical fiber F1 or the collimator 2 at a slight angle (several mrad or less). The diameter of the focused spot on the input surface of the output optical fiber F can become larger due to axial misalignment aberration, but if the effect of reducing the vignetting component caused by the prism mirror 6 becomes greater, the fiber coupling efficiency can be further improved.

[0049] In addition, if an HR coating (anti-reflection coating) is applied to optical elements such as optical fibers, collimators, and focusing lenses, Fresnel loss is reduced, and the output of the laser light output from the optical fiber is increased.

[0050] In addition, the light components not reflected by the prism mirror may be absorbed by a damper or diffused by a diffuser. Furthermore, to remove laser light that does not contribute to fiber coupling and to effectively remove scattered light, the surfaces of the prism mirror other than the reflecting surface may be subjected to an AR coating or sanding.

[0051] However, since a condenser lens, which is a transmission element, may be damaged when the laser output is large, a radiation mirror may be used instead of such a condenser lens, or a cooling mechanism (air-cooling mechanism or water-cooling mechanism) may be provided for the condenser lens.

[0052] In the above embodiment, a configuration is adopted in which laser light emitted from multiple (three) laser light sources is propagated through multiple (three) light source optical fibers F1 to F3, and the laser light LB1 to LB3 emitted from each light source optical fiber F1 to F3 is guided to each collimator 2 to 4, but a configuration may be adopted in which laser light emitted from multiple laser light sources is guided directly to each collimator 2 to 4.

[0053] In addition, in the above embodiment, the number of laser light sources and the light source optical fibers F1 to F3 that propagate the laser light emitted from these laser light sources is three, but this number is not limited to three and may be two or four or more.

[0054] The above-described embodiment shows one example of the present invention, and the scope of application of the present invention should not be limited to the embodiment. It goes without saying that various modifications are possible within the scope of the claims and the technical ideas described in the specification and drawings.

[0055] That is, the exemplary embodiment described above is a specific example of the following aspects: Current understood by the trader.

[0056] (Item 1) The laser device described in item 1 is First and second laser beams are respectively emitted. and third a laser light source; an output optical fiber having an axis and configured to output laser light from the laser device to the outside; The first and second and third a multiplexing optical system that multiplexes laser light coming from laser light sources and makes the multiplexed laser light enter the output optical fiber, The combining optical system includes: The first and second and third The first and second laser beams are converted into parallel beams by the laser light source. and third A collimator; The laser light coming from the second collimator is collimated to the axis. In a parallel direction Inducing Surface a first prism mirror having a surface for guiding the laser light coming from the third collimator in a direction parallel to the axis; a guidance optical system having The first Collimator Arriving from Parallel to the axis laser light and the second and after being converted into parallel light by the third collimator, it is guided in a direction parallel to the axis by the guidance optical system and arrives. do each Laser light and 、 a focusing optical system for focusing light onto the output optical fiber; It is something that the guiding optical system guides the laser light coming from the second and third collimators so that a straight line connecting an optical axis of the laser light coming from the first collimator and an optical axis of each laser light that has been converted into parallel light by the second and third collimators and then guided by the guiding optical system forms an equilateral triangle, and so that the centroid of the equilateral triangle coincides with the axis center, Each of the first and second prism mirrors has a flat top surface facing the laser light coming from the first collimator, and the angle formed by the top surfaces of the first and second prism mirrors on the sides facing the laser light coming from the first collimator is set to 120°. It is characterized by:

[0057] No. 1 According to the laser device described in the paragraph, the laser beams emitted from the three laser light sources and combined by the combining optical system are efficiently incident on the axis of the output optical fiber, thereby further improving the fiber coupling efficiency.

[0058] Also, No. 1 According to the laser device described in the paragraph, the laser light emitted from the first laser light source is 、It can travel straight through the 120° space sandwiched between the inclined surfaces of the two prism mirrors without interfering with the two prism mirrors.

[0059] (No. 2 section) No. 2 In the laser device described in the item 1, and third Each of the laser light sources includes a plurality of laser elements, a shaping optical system that shapes the laser light emitted from the plurality of laser elements, and The relevant The optical fiber for the light source is provided after the shaping optical system.

[0060] According to the laser device described in paragraph 2, the first and second and third The laser light source is composed of a laser element, a shaping optical system, and a light source optical fiber, and emits highly directional laser light.

[0061] (No. 3 Section) No. 3 The laser device described in the paragraph The aforementioned No. 2 The laser light coming from the collimator is reflected, The first prism mirror Lead No. 1 reflective optical system a second reflecting optical system that reflects the laser light coming from the third collimator and guides it to the second prism mirror; The device is characterized by further comprising:

[0062] No. 3 According to the laser device described in paragraph 1, Second and third The laser light collimated by the collimator can be reflected by a reflecting optical system and guided to a guidance optical system.

[0063] (Item 4) The guidance optical system described in item 4 is A guidance optical system in which a first laser beam and second and third laser beams having optical axes not parallel to the optical axis of the first laser beam are incident from respective predetermined directions, a first prism mirror having a surface for guiding the second laser beam so that the optical axis of the second laser beam is parallel to the optical axis of the first laser beam; and a second prism mirror having a surface for guiding the third laser beam so that the optical axis of the third laser beam is parallel to the optical axis of the first laser beam, the guidance optical system guides the second and third laser beams so that a straight line connecting an optical axis of the first laser beam and an optical axis of the second and third laser beams guided by the first and second prism mirrors forms an equilateral triangle; Each of the first and second prism mirrors has a top surface that is a flat surface facing the first laser light, and the angle formed by each of the top surfaces of the first and second prism mirrors on the side facing the first laser light is set to 120°.

[0064] According to the guidance optical system described in item 4, the three laser beams are efficiently incident on the axis of the output optical fiber, thereby further improving the fiber coupling efficiency.

[0065] Furthermore, according to the guidance optical system described in paragraph 4, the first laser light can travel straight through the space sandwiched between the inclined surfaces of the two prism mirrors at an angle of 120° without interfering with the two prism mirrors. [Explanation of symbols]

[0066] 1. Laser device 2. First collimator 3 Second collimator 4. Third collimator 5 Prism mirror (first guidance optical system) 6 Prism mirror (second guidance optical system) 5a, 5b Reflecting surface of prism mirror 5b, 6b Top surface of prism mirror 7. Condenser lens (condensing optical system) 8,9 Reflective mirror (reflection optical system) 10 base 13 Parallel Plates 14 Inclined Plate 24 Lens holder CW multiplexing optical system F Output optical fiber F1~F3 Optical fiber for light source G centroid of an equilateral triangle LB, LB1 to LB3 laser light L1~L3 Parallel light O1~O3 Axis of parallel light R1 First laser light source R2 Second laser light source R3 Third laser source S1~S3 base reference plane

Claims

1. 1. A laser device, comprising: first, second, and third laser light sources each emitting a laser beam; an output optical fiber having an axis and configured to output laser light from the laser device to the outside; a multiplexing optical system that multiplexes the laser beams coming from the first, second, and third laser light sources and makes the multiplexed laser beams enter the output optical fiber, The combining optical system includes: first, second, and third collimators for converting the laser beams coming from the first, second, and third laser light sources into parallel beams, respectively; a guiding optical system including a first prism mirror having a surface that guides the laser light coming from the second collimator in a direction parallel to the axis, and a second prism mirror having a surface that guides the laser light coming from the third collimator in a direction parallel to the axis; a focusing optical system that focuses, onto the output optical fiber, the laser light coming from the first collimator and parallel to the axis, and the laser light that has been converted into parallel light by the second and third collimators and then guided in a direction parallel to the axis by the guiding optical system, the guiding optical system guides the laser light coming from the second and third collimators so that a straight line connecting an optical axis of the laser light coming from the first collimator and an optical axis of each laser light that has been converted into parallel light by the second and third collimators and then guided by the guiding optical system forms an equilateral triangle, and so that the centroid of the equilateral triangle coincides with the axis center, Each of the first and second prism mirrors has a flat top surface facing the laser light coming from the first collimator, and the angle formed by the top surfaces of the first and second prism mirrors on the sides facing the laser light coming from the first collimator is set to 120°. A laser device characterized by:

2. 2. The laser device according to claim 1, wherein each of the first, second, and third laser light sources comprises a plurality of laser elements, a shaping optical system that shapes the laser light emitted from the plurality of laser elements, and a light source optical fiber provided downstream of the shaping optical system.

3. 3. The laser device according to claim 1, further comprising: a first reflecting optical system that reflects the laser light coming from the second collimator and guides it to the first prism mirror; and a second reflecting optical system that reflects the laser light coming from the third collimator and guides it to the second prism mirror.

4. A guidance optical system in which a first laser beam and second and third laser beams having optical axes not parallel to the optical axis of the first laser beam are incident from predetermined directions, the guidance optical system includes a first prism mirror having a surface that guides the second laser beam so that the optical axis of the second laser beam is parallel to the optical axis of the first laser beam, and a second prism mirror having a surface that guides the third laser beam so that the optical axis of the third laser beam is parallel to the optical axis of the first laser beam, the guidance optical system guides the second and third laser beams so that a straight line connecting an optical axis of the first laser beam and an optical axis of the second and third laser beams guided by the first and second prism mirrors forms an equilateral triangle; Each of the first and second prism mirrors has a flat top surface facing the first laser light, and the angle formed by the top surfaces of the first and second prism mirrors on the sides facing the first laser light is set to 120°. A guidance optical system characterized by:

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