Laser beam combining device and laser beam combining method

Abstract

The invention discloses a laser beam combining device and method, the laser beam combining device comprises a plurality of laser units, a wave locking assembly and a beam combining assembly, and the laser units are used for outputting light beams; the wave locking assembly comprises a beam splitter and a grating, the grating is arranged at the reflecting end of the beam splitter, a light beam output by the laser unit is emitted to the beam splitter, and wavelength locking is carried out through the grating; the beam combining assembly is used for combining the light beams output by the wave locking assembly in pairs step by step until the light beams output by all the laser units are combined into one beam; the beam combining assembly comprises a polarization state conversion device, a reflecting mirror and a polarization beam combining device, the polarization state conversion device is used for adjusting the polarization direction of the light beams, and the reflecting mirror is used for adjusting the light paths of the light beams so that the two light beams in the same group can enter the polarization beam combining device; and the polarization beam combining device is used for combining the two light beams subjected to polarization direction and light path adjustment. The light-to-light conversion efficiency is high, the light spot brightness after beam combination is improved, and the light beam quality is improved.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and in particular relates to a laser beam combining device and a laser beam combining method. Background Art

[0002] Semiconductor lasers have the advantages of wide wavelength coverage, high electro-optical conversion efficiency, small size, good stability, low cost, and long life, and have broad application prospects in laser processing, scientific research, health care, etc. However, the poor beam quality of semiconductor lasers in related technologies limits their application. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention provides a laser beam combining device, which can improve the quality of the beam.

[0005] An embodiment of the present invention further provides a laser beam combining method.

[0006] The laser beam combining device according to an embodiment of the present invention comprises:

[0007] A plurality of laser units, each of which is used to output a light beam;

[0008] A wavelength locking component, wherein the wavelength locking component comprises a beam splitter and a grating, wherein the grating is placed at the reflection end of the beam splitter, and the light beam output by the laser unit is directed toward the beam splitter and wavelength locked by the grating;

[0009] A beam combining component, the beam combining component is used to combine the light beams output by the wave locking component in groups of two at a time until the light beams output by all the laser units are combined into one beam;

[0010] The beam combining component includes a polarization state conversion device, a reflector and a polarization beam combining device. The polarization state conversion device is used to adjust the polarization direction of the light beam. The reflector is used to adjust the optical path of the light beam so that two light beams in the same group enter the polarization beam combining device. The polarization beam combining device is used to combine the two light beams whose polarization directions and optical paths have been adjusted.

[0011] The laser beam combining device of the embodiment of the present invention can combine the parametrically combined light beams and achieve the effects of phase locking and spectrum narrowing. The light-to-light conversion efficiency is high, the brightness of the light spot after combining is increased, and the beam quality is improved.

[0012] In some embodiments, the laser unit is a single-tube semiconductor laser, and the light beam output by the laser unit is linearly polarized light;

[0013] And / or, the wavelength range of the light beam output by the laser unit is 450 nm to 2000 nm, and the wavelength interval range of the light beams output by a plurality of the laser units is smaller than the spectrum width of 2 nm.

[0014] In some embodiments, the plurality of laser units are linearly arranged along the first direction, the light beams output by each laser unit correspond to one beam splitter, the optical paths of the light beams output by the laser unit to the grating are equal, and the optical paths of the two light beams to the same polarization beam combiner are equal;

[0015] And / or, the light beam output by the laser unit has the same spectrum, phase and frequency after passing through the wave-locking component.

[0016] In some embodiments, the grating is a plane diffraction grating, and the reflectivity of the plane diffraction grating is greater than 90%;

[0017] And / or, the reflectivity R of the beam splitter satisfies: 10%<R<50%;

[0018] And / or, the plane diffraction grating has a coating layer, and the wavelength of the coating layer corresponds to the wavelength of the light beam output by the laser unit;

[0019] And / or, the number of the gratings is 1.

[0020] In some embodiments, the surfaces of the grating and the reflector have a reflective film, and the surfaces of the beam splitter, the polarization state conversion device, and the polarization beam combining device are coated with an anti-reflection film;

[0021] And / or, the damage thresholds of the beam splitter, grating, polarization state conversion device, reflector and polarization beam combining device are greater than the beam energy output by the laser unit.

[0022] In some embodiments, the light beam entering the beam splitter and the light beam entering the polarization beam combiner are coaxially combined, the fast axis and the slow axis of the light beam entering the beam splitter are coincident, and the fast axis and the slow axis of the light beam entering the polarization beam combiner are coincident;

[0023] And / or, the polarization state conversion device is used to convert the wavelength-locked light beam into a light beam with a parallel polarization direction and passing through the polarization beam combining device, and the polarization direction of the light beam on the transmission side of the polarization beam combining device is perpendicular to the polarization direction of the light beam on the reflection side of the polarization beam combining device.

[0024] In some embodiments, the number of the laser units is 2N, the number of the beam splitters is 2N, and the number of the beam combining components is 2N-1;

[0025] Wherein, N is greater than or equal to 1.

[0026] In some embodiments, when N is greater than or equal to 2, the number of the beam combining components is greater than or equal to 3, and the beam combining components are divided into N first beam combining components and N-1 second beam combining components, the first beam combining component includes 1 polarization state conversion device, 1 reflector and 1 polarization beam combining device, and the second beam combining component includes 2 polarization state conversion devices, 1 reflector and 1 polarization beam combining device;

[0027] The polarization state conversion device in the second beam combining component is used to adjust the polarization direction of the combined light beam and convert it into linear polarized light.

[0028] In some embodiments, the polarization state conversion device is a wave plate or a rotator.

[0029] The laser beam combining method according to an embodiment of the present invention comprises the following steps:

[0030] A wave-locking component having a beam splitter and a grating, and a beam combining component having a polarization state conversion device, a reflector and a polarization beam combining device are configured;

[0031] A plurality of laser beams are configured, each laser beam is wavelength-locked through the beam splitter and the grating and then enters the beam combining component;

[0032] A plurality of laser beams are combined in pairs for primary beam combining, and each beam combining component combines two laser beams, and at least one of the two laser beams entering the same beam combining component has its polarization direction adjusted by the polarization state conversion device and its optical path adjusted by the reflector before entering the polarization beam combining device for beam combining;

[0033] When the number of laser beams after the first-stage beam combination is greater than or equal to 2, the previous step is repeated to combine the multiple laser beams that have been combined again until they are combined into one laser beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic structural diagram of a laser beam combining device according to an embodiment of the present invention.

[0035] Figure 2 It is a schematic structural diagram of a laser beam combining device according to another embodiment of the present invention.

[0036] Figure 3 It is a schematic structural diagram of a laser beam combining device according to another embodiment of the present invention.

[0037] Figure 4 It is a schematic diagram of the change of the polarization state of the light beam in the laser beam combining device according to an embodiment of the present invention.

[0038] Reference numerals:

[0039] 100. Laser beam combining device;

[0040] 1. Laser unit;

[0041] 2. Wave-locking components;

[0042] 201, beam splitter; 202, grating;

[0043] 3. beam combining assembly; 31. first beam combining assembly; 32. second beam combining assembly;

[0044] 301. Polarization state conversion device; 302. Reflector; 303. Polarization beam combining device. DETAILED DESCRIPTION

[0045] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0046] The following combination Figures 1 to 4 The laser beam combining device 100 and the laser beam combining method according to the embodiment of the present invention are described in detail.

[0047] like Figure 1-Figure 4 As shown, the laser beam combining device 100 according to the embodiment of the present invention comprises a plurality of laser units 1 , a wave-locking component 2 and a beam combining component 3 .

[0048] The laser unit 1 is used to output a light beam. A plurality of laser units 1 can output a plurality of light beams. The embodiment of the present invention improves the light beam quality by combining the plurality of light beams.

[0049] The wavelength locking component 2 includes a beam splitter 201 and a grating 202 . The grating 202 is placed at the reflection end of the beam splitter 201 . The light beam output by the laser unit 1 is directed toward the beam splitter 201 and is wavelength locked by the grating 202 .

[0050] The beam splitter 201 is used to split the output light beam of the laser unit 1 into two paths. The grating 202 is placed at the reflecting end of the beam splitter 201 and is used to regulate the light beam of the laser unit 1 at a fixed spectral interval and lock it at a fixed central wavelength. The output light beams of multiple laser units 1 are spectrally locked through the wavelength locking component 2.

[0051] The beam combining component 3 is used to combine the light beams output by the wave-locking component 2 step by step in groups of two, until the light beams output by all the laser units 1 are combined into one beam.

[0052] The beam combining component 3 includes a polarization state conversion device 301, a reflector 302 and a polarization beam combining device 303. The polarization state conversion device 301 is used to adjust the polarization direction of the light beam and change the polarization direction of the light beam. The reflector 302 is used to adjust the optical path of the light beam so that two light beams in the same group enter the polarization beam combining device 303. The polarization beam combining device 303 is used to combine the two light beams whose polarization directions and optical paths have been adjusted.

[0053] The laser beam combining device 100 of the embodiment of the present invention can combine parametrically combined light beams and achieve the effects of phase locking and spectrum narrowing. It has high light-to-light conversion efficiency, improves the brightness of the combined light spot, and improves the beam quality.

[0054] Optionally, the number of beam combining components 3 is determined according to the number of laser units 1 .

[0055] For example, when the number of laser units 1 is 2, as Figure 2 As shown, only one beam combining component 3 is required, and only one level of beam combining is required.

[0056] For another example, when the number of laser units 1 is 4, Figure 1 As shown, three beam combining components 3 are required to perform three beam combining, which is completed in two stages. The four laser units 1 are divided into two groups, two by two, and the first-stage beam combining is completed by two beam combining components 3 respectively, and then the third beam combining component 3 is used to perform the second-stage beam combining on the two beams that have undergone the first-stage beam combining.

[0057] For another example, when the number of laser units 1 is 6, Figure 3 As shown, five beam combining components 3 are required at this time.

[0058] Furthermore, the polarization state conversion device 301 is used to convert the wavelength-locked light beam into a light beam with a parallel polarization direction and passing through the polarization beam combiner 303, and the polarization direction of the light beam on the transmission side of the polarization beam combiner 303 is perpendicular to the polarization direction of the light beam on the reflection side of the polarization beam combiner 303.

[0059] In some embodiments, the laser unit 1 is a single-tube semiconductor laser, and the laser beam combining device 100 of the embodiment of the present invention is a coherent beam combining device of multiple single-tube semiconductor lasers.

[0060] The light beam output by the laser unit 1 is linearly polarized light, and the wavelength range of the light beam output by the laser unit 1 is 450nm to 2000nm, and the wavelength interval range of the light beams output by the multiple laser units 1 is less than the spectral width of 2nm. In the embodiment of the present invention, the light beam type, wavelength, and wavelength interval of different light beams are constrained to improve the light-to-light conversion efficiency and ensure the light beam quality.

[0061] Furthermore, the wavelength interval range of the light beams output by the plurality of laser units 1 is smaller than the spectrum width of 1 nm.

[0062] Furthermore, in the embodiment of the present invention, the number of semiconductor chips in each laser unit 1 is greater than or equal to one, the semiconductor laser is in the form of a single tube, the semiconductor laser chips are substantially the same, and the wavelength is generally consistent with that of the composed laser unit 1. The polarized light of each semiconductor laser chip should be linearly polarized light, and the polarization state should remain consistent.

[0063] In some embodiments, multiple laser units 1 are arranged linearly along a first direction, the light beam output by each laser unit 1 corresponds to a beam splitter 201, there is one grating 202, the optical path of the light beam output by the laser unit 1 reaching the grating 202 is equal, and the optical path of the two light beams reaching the same polarization beam combining device 303 is equal.

[0064] The grating 202 of the embodiment of the present invention has a coating layer, the wavelength of the coating layer corresponds to the wavelength of the light beam output by the laser unit 1, and the divergence angles of the light beams output by each laser unit 1 are the same, so that the light beams output by the wave-locking component 2 are consistent in spectrum, frequency and phase, thereby improving the quality of the beam combination.

[0065] In the embodiment of the present invention, wavelength locking can be performed on multiple laser units 1, and the light beams participating in the subsequent beam combining can be ensured to be consistent in spectrum, phase and frequency. The brightness of the light spot after beam combining is more than twice that of the wavelength combining laser in the related art, and the spectrum width is much smaller than the wavelength combining laser published in the related art.

[0066] The embodiments of the present invention can achieve the effects of phase locking and spectrum narrowing, and the structure is greatly simplified compared to the coherent beam combining laser realized by relying on the phase control device in the related technology, thereby greatly reducing the device cost.

[0067] In some embodiments, the grating 202 is a plane diffraction grating, the reflectivity of the plane diffraction grating is greater than 90%, and the reflectivity R of the beam splitter 201 satisfies: 10%<R<50%.

[0068] The reflectivity of the plane diffraction grating can be 91%, 93%, 95% or 96.3%, and the reflectivity of the beam splitter 201 can be 11%, 18%, 22%, 26.4%, 42.6% or 49%. When the reflectivity of the plane diffraction grating is less than or equal to 90%, and the reflectivity of the beam splitter 201 is less than or equal to 10% or greater than or equal to 50%, the beam quality will be affected, affecting the light-to-light conversion efficiency.

[0069] Furthermore, the grating 202 is a reflective volume Bragg grating.

[0070] In some embodiments, the surfaces of the grating 202 and the reflector 302 have a reflective film, and the surfaces of the beam splitter 201, the polarization state conversion device 301, and the polarization beam combining device 303 are coated with an anti-reflection film, which can improve the reflectivity of the grating 202 and the reflector 302, and improve the transmittance of the beam splitter 201, the polarization state conversion device 301, and the polarization beam combining device 303.

[0071] Furthermore, both the reflective film and the anti-reflective film have wavelength bands corresponding to the light beam to meet their respective characteristic requirements.

[0072] Furthermore, the damage threshold of the beam splitter 201, the grating 202, the polarization state conversion device 301, the reflector 302 and the polarization beam combiner 303 is greater than the beam energy output by the laser unit 1, thereby preventing the beam splitter 201, the grating 202, the polarization state conversion device 301, the reflector 302 and the polarization beam combiner 303 from being damaged and being able to resist laser damage.

[0073] In some embodiments, the light beam entering the beam splitter 201 and the light beam entering the polarization beam combiner 303 are both coaxially combined, and the fast axis and slow axis of the light beam entering the beam splitter 201 and the fast axis and slow axis of the light beam entering the polarization beam combiner 303 are both overlapped.

[0074] That is, the fast axes and slow axes of the light beams entering the beam splitter 201 roughly overlap, and the fast axes and slow axes of the light beams entering the polarization beam combiner 303 roughly overlap.

[0075] Furthermore, all the light beams in the embodiment of the present invention are transmitted along the same optical axis, and the fast axis and the slow axis are completely aligned.

[0076] In some embodiments, the number of laser units 1 is 2N, the number of beam splitters 201 is 2N, and the number of beam combining components 3 is 2N-1; wherein N is greater than or equal to 1.

[0077] For example, N is 1, 2, 3, 5 or 7, etc., and the light beams output by multiple laser units 1 can be combined into one beam according to needs.

[0078] The beam splitter 201 and the laser unit 1 are arranged one by one. The light beam output by the laser unit 1 is split into two paths by the beam splitter 201. One of the paths is wavelength-selected by the grating 202 and returns to the semiconductor laser along the original path for wavelength locking. Figure 1 As shown in the figure, the positions of the light beams outputted by each laser unit 1 on the beam splitter 201 and the grating 202 coincide with each other, and the other beam enters the corresponding beam combining component 3. Thus, the beams outputted by each laser unit 1 are wavelength locked.

[0079] Further, in some embodiments, when N is greater than or equal to 2, the number of the beam combining components 3 is greater than or equal to 3, and the beam combining component 3 is divided into N first beam combining components 31 and N-1 second beam combining components 32, the first beam combining component 31 includes 1 polarization state conversion device 301, 1 reflector 302 and 1 polarization beam combining device 303, and the second beam combining component 32 includes 2 polarization state conversion devices 301, 1 reflector 302 and 1 polarization beam combining device 303;

[0080] The polarization state conversion device 301 in the second beam combining component 32 is used to adjust the polarization direction of the combined light beam and convert it into linear polarized light.

[0081] That is to say, the light beams outputted by the plurality of laser units 1 are combined in a multi-stage beam combining manner in pairs after passing through the wave-locking component 2 .

[0082] Taking N equal to 2 as an example, the specific beam combining method is that the light beams output by the four laser units 1 are respectively divided into two groups after passing through the wave locking component 2, and are first combined by the first beam combining component 31. The initial polarization directions of the two light beams entering the same first beam combining component 31 are the same, so the polarization direction of one of the light beams is rotated 90° by the polarization state conversion device 301, and then combined with the other light beam whose polarization direction has not been changed through the polarization combining device 303, completing the primary beam combining of the two groups of light beams.

[0083] After the primary beam combination, there are still two beams, so they need to enter the second beam combination component 32 for secondary beam combination. Since the beam formed after beam combination contains two polarized lights with polarization directions perpendicular to each other, the two beams entering the second beam combination component 32 need to change their polarization directions through the polarization state conversion device 301, respectively, to adjust each beam to linear polarized light with the same polarization reflection, and to form two linear polarized lights with polarization directions perpendicular to each other when entering the polarization beam combination device 301, and then combine them through the polarization beam combination device 303. When N is greater than 2, all subsequent beams will repeat this operation, and finally 2N laser beams will be combined into one beam for output.

[0084] All light beams of the present invention are coaxially combined in the beam splitter 201 and the polarization beam combiner 303, the fast axis and the slow axis of the light beam completely overlap, and the brightness of the combined light beam is approximately equal to 4 times the sum of the brightness values ​​of each laser unit 1 before combining.

[0085] In some embodiments, the polarization state conversion device 301 includes a wave plate or an optical rotator.

[0086] In the beam combining assembly 3 of the present invention, all the light beams reaching the polarization beam combining device 303 are linearly polarized light. When the polarization directions of the two light beams entering the polarization beam combining device 303 are parallel, the polarization direction of one of the light beams needs to be adjusted by 90 degrees through the polarization state conversion device 301. The light beam formed after the polarization beam combining device 303 has two polarized lights with mutually perpendicular polarization directions. In order to perform the next level of beam combining, the polarization state conversion device 301 needs to be used to convert the light beams into linear polarized lights with the same polarization direction. The light beams participating in the beam combining are combined in pairs, specifically two linear polarized lights with mutually perpendicular polarization directions, and the optical paths of the laser beams participating in the beam combining to reach the corresponding polarization beam combining device 303 are equal.

[0087] The laser beam combining method according to an embodiment of the present invention comprises the following steps:

[0088] S1. A wave-locking component having a beam splitter and a grating, and a beam combining component having a polarization state conversion device, a reflector and a polarization beam combining device are configured.

[0089] S2. Multiple laser beams are configured, and each laser beam is wavelength-locked through a beam splitter and a grating before entering a beam combining component.

[0090] Laser units are arranged to output laser beams, the number of laser beams is 2N, the laser beams are linearly polarized light, and the number of beam splitters is the same as the number of laser beams and corresponds one to one.

[0091] The arrangement form, structural parameters, etc. of the laser unit, the wave-locking component, and the beam-combining component are the same as those in the above embodiment and will not be described in detail.

[0092] S3. Multiple laser beams are combined in pairs for the first stage. Each beam combining component combines two laser beams. At least one of the two laser beams entering the same beam combining component is adjusted in polarization direction by a polarization state conversion device and in optical path by a reflector before entering a polarization beam combining device for combining.

[0093] S4. When the number of laser beams after the first-stage beam combination is greater than or equal to 2, the previous step is repeated to combine the multiple laser beams that have been combined again until they are combined into one laser beam.

[0094] The following is a further detailed description with reference to the accompanying drawings:

[0095] like Figure 1 , Figure 4 As shown, taking N=2 as an example, the four laser units generate linear polarized light S1, linear polarized light S2, linear polarized light S3 and linear polarized light S4 respectively, the plane diffraction grating generates feedback light of fixed wavelength, which is used to lock the spectrum of the laser beam to the same band, the polarization conversion device is used to convert the polarization direction of the laser beam, and the polarization beam combining device is used to combine two beams with polarization directions perpendicular to each other.

[0096] The process is as follows:

[0097] The linearly polarized lights S1, S2, S3, and S4 are arranged linearly from top to bottom. The optical path length of the laser beams output by each laser unit to the plane diffraction grating is completely equal. Each laser beam is transmitted coaxially and will generate feedback light of a fixed wavelength after reaching the plane diffraction grating. The feedback light modulates the inside of the laser chip to convert the linearly polarized lights S1, S2, S3, and S4 into laser beams with consistent spectrum, frequency, phase, and polarization, and enter the beam combining component.

[0098] The polarization direction of the linear polarized light S1 is rotated 90° by the polarization state conversion device 301-1, and then reflected by the reflector 302-1 into the polarization beam combiner 303-1, where it is combined with the linear polarized light S2 whose polarization direction has not been changed, and the output light beam is linear polarized light with polarization directions perpendicular to each other.

[0099] After the first beam combination, S1 and S2 continue to pass through the polarization state conversion device 301-3, wherein the polarization direction of S2 is rotated by 90 degrees, while S1 remains unchanged and is reflected by the reflector 302-3 into the polarization beam combining device 303-3.

[0100] The polarization direction of the linear polarized light S3 is rotated 90° by the polarization state conversion device 301-2, and then reflected by the reflector 302-2 into the polarization beam combiner 303-2, where it is combined with the linear polarized light S4 whose polarization direction has not been changed, and the output light beam is linear polarized light with polarization directions perpendicular to each other.

[0101] After the first beam combining, S3 and S4 continue to pass through the polarization state conversion device 301-4, where the polarization direction of S3 is rotated 90°, and S4 remains unchanged. The linearly polarized lights S1, S2, S3, and S4 are beam combined in the polarization beam combining device 303-3, and the final output beam is linearly polarized light with polarization directions perpendicular to each other, completing the wave locking and beam combining output of the four laser units.

[0102] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0103] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0104] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0105] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0106] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0107] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A laser beam combining device, characterized in that: include: A plurality of laser units, each of which is used to output a light beam; A wavelength locking component, wherein the wavelength locking component comprises a beam splitter and a grating, wherein the grating is placed at the reflection end of the beam splitter, and the light beam output by the laser unit is directed toward the beam splitter and wavelength locked by the grating; A beam combining component, the beam combining component is used to combine the light beams output by the wave locking component in groups of two at a time until the light beams output by all the laser units are combined into one beam; The beam combining component includes a polarization state conversion device, a reflector and a polarization beam combining device. The polarization state conversion device is used to adjust the polarization direction of the light beam. The reflector is used to adjust the optical path of the light beam so that two light beams in the same group enter the polarization beam combining device. The polarization beam combining device is used to combine the two light beams whose polarization directions and optical paths have been adjusted.

2. The laser beam combining device according to claim 1, characterized in that: The laser unit is a single-tube semiconductor laser, and the light beam output by the laser unit is linearly polarized light; And / or, the wavelength range of the light beam output by the laser unit is 450 nm to 2000 nm, and the wavelength interval range of the light beams output by a plurality of the laser units is smaller than the spectrum width of 2 nm.

3. The laser beam combining device according to claim 1, characterized in that: The plurality of laser units are linearly arranged along a first direction, the light beams output by each laser unit correspond to one beam splitter, the optical paths of the light beams output by the laser unit to the grating are equal, and the optical paths of the two light beams to the same polarization beam combiner are equal; And / or, the light beam output by the laser unit has the same spectrum, phase and frequency after passing through the wave-locking component.

4. The laser beam combining device according to claim 1, characterized in that: The grating is a plane diffraction grating, and the reflectivity of the plane diffraction grating is greater than 90%; And / or, the reflectivity R of the beam splitter satisfies: 10%<R<50% And / or, the plane diffraction grating has a coating layer, and the wavelength of the coating layer corresponds to the wavelength of the light beam output by the laser unit; And / or, the number of the gratings is 1.

5. The laser beam combining device according to claim 1, characterized in that: The surfaces of the grating and the reflector are provided with a reflective film, and the surfaces of the beam splitter, the polarization state conversion device, and the polarization beam combining device are coated with an anti-reflection film; And / or, the damage thresholds of the beam splitter, grating, polarization state conversion device, reflector and polarization beam combining device are greater than the beam energy output by the laser unit.

6. The laser beam combining device according to claim 1, characterized in that: The light beam entering the beam splitter and the light beam entering the polarization beam combiner are both coaxially combined, the fast axis and the slow axis of the light beam entering the beam splitter are both coincident, and the fast axis and the slow axis of the light beam entering the polarization beam combiner are both coincident; And / or, the polarization state conversion device is used to convert the wavelength-locked light beam into a light beam with a parallel polarization direction and passing through the polarization beam combining device, and the polarization direction of the light beam on the transmission side of the polarization beam combining device is perpendicular to the polarization direction of the light beam on the reflection side of the polarization beam combining device.

7. The laser beam combining device according to any one of claims 1 to 6, characterized in that: The number of the laser units is 2N, the number of the beam splitters is 2N, and the number of the beam combining components is 2N-1; Wherein, N is greater than or equal to 1.

8. The laser beam combining device according to claim 7, characterized in that: When N is greater than or equal to 2, the number of the beam combining components is greater than or equal to 3, and the beam combining components are divided into N first beam combining components and N-1 second beam combining components, the first beam combining component includes 1 polarization state conversion device, 1 reflector and 1 polarization beam combining device, and the second beam combining component includes 2 polarization state conversion devices, 1 reflector and 1 polarization beam combining device; The polarization state conversion device in the second beam combining component is used to adjust the polarization direction of the combined light beam and convert it into linear polarized light.

9. The laser beam combining device according to claim 8, characterized in that: The polarization state conversion device is a wave plate or a polarization rotator.

10. A laser beam combining method, characterized in that: The following steps are involved: A wave-locking component having a beam splitter and a grating, and a beam combining component having a polarization state conversion device, a reflector and a polarization beam combining device are configured; A plurality of laser beams are configured, each laser beam is wavelength-locked through the beam splitter and the grating and then enters the beam combining component; A plurality of laser beams are combined in pairs for primary beam combining, and each beam combining component combines two laser beams, and at least one of the two laser beams entering the same beam combining component has its polarization direction adjusted by the polarization state conversion device and its optical path adjusted by the reflector before entering the polarization beam combining device for beam combining; When the number of laser beams after the first-stage beam combination is greater than or equal to 2, the previous step is repeated to combine the multiple laser beams that have been combined again until they are combined into one laser beam.

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