CN108429129A - The conjunction beam system and method for multi-thread array semiconductor laser grating external-cavity spectrum - Google Patents

Abstract

The disclosure provides a multi-linear array semiconductor laser grating external cavity spectrum beam combining system, including: multiple beam combining units, including: multiple linear array semiconductor lasers, arranged at equal intervals along the x direction and the y direction on the horizontal plane; The unit is set in front of the linear array semiconductor laser; the triangular prism is set in front of each beam combining unit to reflect the beam; the transformation transmission lens is set in the outgoing direction of the beam passing through the prism, and the combined beam emitted by the beam combining unit is transformed The transmission lens becomes a convergent beam; the diffraction grating is set at the converging point a of the combined beam, and the convergent beam passes through the diffraction grating to generate a diffracted beam; the coupling output mirror is set in the direction of the diffracted beam perpendicular to the main axis beam, and the vertical incident on it The diffracted beam is reflected and fed back to form a stable oscillation. The present disclosure can obtain high-power, high-brightness laser output, and is not limited by the space for combining beams and the number of line arrays.

Description

Beam combining system and method for multi-linear array semiconductor laser grating external cavity spectroscopy

technical field

The present disclosure relates to the field of semiconductor lasers, and in particular to a multi-linear array semiconductor laser grating external cavity spectral beam combining system and method.

Background technique

High-power semiconductor lasers have the advantages of high electro-optical conversion efficiency, small size, and high reliability. However, due to the limitations of their waveguide structure and chip packaging, the beam quality deteriorates and the spatial brightness is not high, which limits their use in laser lighting, pumping, etc. Further applications in the fields of solid-state lasers or fiber lasers, material processing and military industry.

At present, there are two main methods of beam combining of semiconductor lasers, coherent beam combining and incoherent beam combining. Although coherent beam combining can effectively improve and improve the beam quality of the output light of the semiconductor laser array, this method is easily disturbed by the external environment, and it is difficult to obtain high-power stable laser output with the same phase supermode. Incoherent beam combining technology is currently the main method of semiconductor laser beam combining in the world. It mainly combines multiple semiconductor lasers into one beam through spatial beam combining, wavelength combining and polarization beam combining, and increases the output power to improve the system. The purpose of brightness, but based on the limitation of beam combining excitation and required optical devices, the above three beam combining methods cannot achieve ideal scaling and amplification.

The grating external cavity spectral beam combining is fed back through the external cavity. Different beam combining units operate at different wavelengths due to gain competition, and the output beams will be spatially superimposed on the grating along the central unit. The superimposed output beams are combined with each The beam combining unit has the same beam quality, and the spatial brightness of the combined output beam will increase significantly compared with that before beam combining, which improves the output beam quality of the linear array semiconductor laser. However, at present, it is mainly for a single line array to combine beams, but for high-power, high-brightness laser output, it is still limited by the space for combining beams and the number of line arrays. Therefore, there is an urgent need for a multi-line array semiconductor laser grating external cavity spectral beam combining system and method that can greatly increase power and brightness, and is not limited by the beam combining space and the number of line arrays.

Contents of the invention

(1) Technical problems to be solved

The present disclosure provides a multi-linear array semiconductor laser grating external cavity spectral beam combining system and method to at least partially solve the above-mentioned technical problems.

(2) Technical solution

According to one aspect of the present disclosure, a multi-linear semiconductor laser grating external cavity spectral beam combining system is provided, including:

Multiple beam combining units, including:

A plurality of linear array semiconductor lasers are arranged at equal intervals along the x direction and the y direction on the horizontal plane;

A collimation unit is arranged in front of the linear array semiconductor laser to obtain a collimated light beam along the fast and slow axes;

Triangular prisms are arranged in front of each beam combining unit to reflect the beams;

The transformation transmission lens is arranged on the outgoing direction of the light beam after passing through the prism, and the combined light beam emitted by the beam combining unit becomes a converging light beam after passing through the transformation transmission lens, and the convergence point is a;

The diffraction grating is arranged at the converging point a of the combined beam, and the convergent beam passes through the diffraction grating to generate a diffracted beam;

The coupling output mirror is arranged in the direction of the diffracted beam of the vertical axis beam, reflects the diffracted beam perpendicularly incident on it, and feeds back the beam of the linear array semiconductor laser to form a stable oscillation.

In some embodiments of the present disclosure, the linear array semiconductor lasers are arranged along the left and right sides with a plurality of triangular prisms as symmetrical axes in the horizontal direction.

In some embodiments of the present disclosure, the linear array semiconductor lasers are arranged with equal height difference in the vertical z direction.

In some embodiments of the present disclosure, after being reflected by the triangular prism, a series of parallel and equidistant combined light beams outputted have the same optical path to the transformation lens.

In some embodiments of the present disclosure, the collimation unit includes:

The slow axis collimating mirror is arranged in front of each of the linear array semiconductor lasers, and is used to reduce the divergence angle of the light beam in the direction of the slow axis;

A fast-axis collimator, arranged in front of each slow-axis collimator, is used to reduce the divergence angle of the light beam in the direction of the fast axis.

In some embodiments of the present disclosure, the fast-axis collimator is a cylindrical microlens, and the slow-axis collimator is a cylindrical microlens array.

In some embodiments of the present disclosure, the reflectance R of the reflective film coated on the triangular prism is >99%.

In some embodiments of the present disclosure, the outcoupling mirror is a flat mirror, and the reflectance of the coated reflective film is 10%.

According to another aspect of the present disclosure, a method for spectral beam combining of multi-linear semiconductor laser gratings is provided, including:

Multiple linear array semiconductor lasers emit light, which are collimated by collimating units in sequence;

The light beams collimated by the fast and slow axes are reflected by the triangular prism and output as a series of parallel and equally spaced combined light beams;

The combined light beams are combined by the conversion lens to form a converging light beam, which is incident on the diffraction grating at different angles;

converging the light beams and completely overlapping at the diffraction grating, diffracted by the diffraction grating to the coupling output mirror;

Reflected by the coupling output mirror, the light beam fed back to the linear array semiconductor laser forms a stable oscillation.

In some embodiments of the present disclosure, after the linear semiconductor laser is diffracted by the diffraction grating and combined with the coupling output mirror, the beam quality in the fast axis direction remains unchanged, and the beam quality in the slow axis direction is reduced to a single The beam quality of the laser unit, the output laser power density and brightness are increased to N times that of a single laser unit, where N is the number of laser units in the direction of spectral beam combining.

(3) Beneficial effects

It can be seen from the above technical solutions that the multi-linear semiconductor laser grating external cavity spectral beam combining system and method of the present disclosure have at least one of the following beneficial effects:

(1) The triangular prism reflects the light beam output from the linear array semiconductor laser after being shaped by the fast-axis collimating mirror and the slow-axis collimating mirror to the transformation transmission lens. On the transformation lens, there is a series of parallel and equally spaced combined beams, and each The combined light beams emitted by the linear array semiconductor lasers have the same optical path and the same beam distribution characteristics when they arrive at the transformation transmission lens; Overlapping occurs, the beam quality in the fast axis direction remains unchanged after beam combining, and the beam quality in the slow axis direction is reduced to the beam quality of a single laser unit, thereby improving the beam quality of the output beam, and due to the increase in the number of linear array semiconductor lasers, Therefore, the output laser power density and brightness are increased to N times that of a single laser unit (N is the number of laser units in the beam combining direction);

(2) Since the linear semiconductor laser grating external cavity spectral beam combining method is closely spaced, the space occupied by the linear semiconductor laser is small, and the outgoing beams do not interfere with each other.

Description of drawings

FIG. 1 is a schematic structural diagram of a multi-linear semiconductor laser grating external cavity spectral beam combining system according to an embodiment of the present disclosure.

Fig. 2 is a side view of a multi-linear array semiconductor laser arranged with equal height difference in the vertical direction according to an embodiment of the present disclosure.

FIG. 3 is a schematic diagram of diffraction of light incident on a diffraction grating according to an embodiment of the present disclosure.

[Description of main component symbols of the embodiment of the present disclosure in the accompanying drawings]

1. Linear array semiconductor laser; 2. Slow axis collimator

3. Fast axis collimator; 4. Triangular prism

5. Transform transmission lens; 6. Diffraction grating

7. Coupling output mirror; 8. Copper block.

Detailed ways

The disclosure provides a multi-line semiconductor laser grating external-cavity spectral beam combining method that can greatly improve power and brightness. A multi-linear array semiconductor laser grating external cavity spectral beam combining method, comprising: a linear array semiconductor laser, a fast axis collimator mirror, a slow axis collimator mirror, a triangular prism, a copper block, a conversion transmission lens, a diffraction grating and a coupling output mirror ;

The linear array semiconductor lasers are placed on the copper block and placed along the left and right sides in the horizontal direction. Preferably, the linear array semiconductor lasers are arranged at equal intervals along the x and y directions; and in the vertical direction using The height differences of the copper blocks are arranged with equal height differences. The slow-axis collimating mirror and the fast-axis collimating mirror are sequentially fixed in front of each linear array semiconductor laser. Each of the linear array semiconductor lasers emits a row of beams collimated by the fast and slow axes, and the beams are reflected by the triangular prism and then output as a row of parallel combined beams with equal intervals. The combined beams are combined by the conversion lens to form a converging beam, which is incident on the diffraction grating at different angles, and completely overlaps at the diffraction grating, and is diffracted by the diffraction grating The function is to diffract onto the outcoupling mirror, and then reflected by the outcoupling mirror to form a stable oscillation for the light beam fed back to the linear array semiconductor laser.

Preferably, the fast-axis collimator is a cylindrical microlens; the slow-axis collimator is a cylindrical microlens array.

Preferably, the reflectivity R of the reflective film coated on the triangular prism is greater than 99%.

Preferably, the optical paths of the combined light beams emitted by each of the linear array semiconductor lasers reaching the conversion lens are equal.

Preferably, after the combined beams are combined by the diffraction grating, they have the beam quality output of a single laser unit.

In the multi-linear array semiconductor laser grating external cavity spectral beam combining system of the present disclosure, since the linear array semiconductor lasers are placed along the left and right sides in the horizontal direction, and arranged at equal intervals along the x and y directions, the copper The height difference of the blocks is arranged with the same height difference, so that the outgoing beams do not interfere with each other, and it has the characteristics of small arrangement space.

The slow-axis collimating mirror and the fast-axis collimating mirror are sequentially fixed in front of each linear array semiconductor laser, and each linear array semiconductor laser emits a column of beams collimated by the fast and slow axes, and the beams pass through After reflection by the triangular prism, the output is a series of parallel and equally spaced combined light beams. The combined light beams emitted by each linear array semiconductor laser have the same optical path to the conversion transmission lens, and the beam distribution characteristics are the same. The combined beams are combined by the conversion transmission lens to form a converging beam, which is incident on the diffraction grating at different angles, and completely overlaps at the diffraction grating, and passes through the diffraction grating Diffraction, diffracted onto the coupling-out mirror, and then reflected by the coupling-out mirror, forming a stable oscillation for the light beam fed back to the linear array semiconductor laser. The laser units after spectral beam combining overlap in space, the beam quality in the fast axis direction remains unchanged after beam combining, and the beam quality in the slow axis direction is reduced to the beam quality of a single laser, thereby improving the beam quality of the output beam, and the laser The power density and brightness are increased by N times (N is the number of laser units in the beam combining direction).

In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

Certain embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which some but not all embodiments are shown. Indeed, various embodiments of the disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth here; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

In the first exemplary embodiment of the present disclosure, a multi-linear semiconductor laser grating external cavity spectral beam combining system is provided. FIG. 1 is a schematic structural diagram of a multi-linear semiconductor laser grating external cavity spectral beam combining system according to an embodiment of the present disclosure. Fig. 2 is a side view of a multi-linear array semiconductor laser arranged with equal height difference in the vertical direction according to an embodiment of the present disclosure. As shown in Figure 1, the multi-linear array semiconductor laser grating external cavity spectral beam combining system of the present disclosure includes: a linear array semiconductor laser 1, a slow axis collimator mirror 2, a fast axis collimator mirror 3, a triangular prism 4, and a transformation transmission lens 5. Diffraction grating 6, outcoupling mirror 7.

Each component of the multi-linear array semiconductor laser grating external cavity spectral beam combining system of this embodiment will be described in detail below.

Referring to FIG. 1 and FIG. 2 , the linear array semiconductor lasers 1 are arranged along the left and right sides in the horizontal direction, and are arranged at equal intervals in the x and y directions at the same time. In the vertical direction, the linear array semiconductor lasers 1 are arranged on the copper block 8 with equal height difference. Adopting the above-mentioned arrangement mode, the emitted light beams do not interfere with each other, and the arrangement space is characterized by a small volume. The front cavity surface of the linear array semiconductor laser 1 is coated with an anti-reflection film with a transmittance above 99%.

The slow axis collimating mirror 2 is fixed in front of each of the linear array semiconductor lasers 1, and is used to reduce the divergence angle of the light beam in the direction of the slow axis, so that the light beam in the direction of the slow axis is collimated. Preferably, the The slow-axis collimating mirror 2 described above is a cylindrical microlens array.

The fast-axis collimating mirror 3 is fixed in front of each slow-axis collimating mirror 2 for reducing the divergence angle of the light beam in the fast-axis direction and collimating the light beam in the fast-axis direction. Preferably, the fast-axis collimating mirror 3 is a cylindrical microlens.

Each of the linear array semiconductor lasers 1 emits a column of combined beams that pass through the slow-axis collimator mirror 2 and the fast-axis collimator mirror 3 to become a parallel column of combined beams, and each of the linear array semiconductor lasers 1 And the slow-axis collimating mirror 2 and the fast-axis collimating mirror 3 fixed in front of the linear array semiconductor laser 1 constitute a beam combining unit, and there are 10 beam combining units in this embodiment.

The triangular prism 4 is arranged in front of each beam combining unit, and the 10 parallel combined light beams emitted by the 10 beam combining units are reflected to the conversion transmission lens 5 sequentially under the action of the triangular prism 4 .

The transmission lens 5 is arranged in the outgoing direction of the light beam passing through the prism 4, and the conversion transmission lens 5 is a cylindrical lens. After being acted by the conversion transmission lens 5, the combined light beams emitted by the 10 beam combining units will converge on the diffraction grating 6, and become convergent light beams after convergence, and the convergence point is a.

Diffraction grating 6 is provided at the converging point a of the combined light beam. Fig. 3 is a schematic diagram of diffraction of light incident on a diffraction grating according to an embodiment of the present disclosure, referring to Fig. 3 , including: incident ray b emitted by a linear array semiconductor laser, diffracted ray c, normal line d of diffraction grating 6, incident ray b and normal The angle θ between the line d and the angle β between the diffracted ray c and the normal line d. When the converging light beam is incident on the diffraction grating 6 at different angles, the angle θ between the incident ray b and the normal d and the angle β between the diffracted ray c and the normal d satisfy the first-order diffraction equation of the grating :

d(sinθ+sinβ)=λ

Wherein, λ is the wavelength, preferably, λ is 940±5 nm or 976±5 nm.

The outcoupling mirror 7 is placed vertically in the direction of the diffracted beam of the main axis beam. The incident light b is diffracted by the diffraction grating 6, and the diffracted light c hits the coupling output mirror 7, and the coupling output mirror 7 reflects the diffracted light beam vertically incident on it, and feeds back to the linear array semiconductor laser 1 The beam forms a stable oscillation. The coupling output mirror is a plane mirror. Preferably, the outcoupling mirror 7 is coated with 10% reflective film.

In the linear array semiconductor laser grating external cavity spectral beam combining method in this embodiment, the linear array semiconductor lasers are arranged closely in space, occupy a small space, and the outgoing beams do not interfere with each other. The triangular prism reflects the light beam output from the linear array semiconductor laser after being shaped by the fast axis collimator mirror and the slow axis collimator mirror to the conversion transmission lens. On the conversion lens, there is a row of parallel and equally spaced combined beams, and each of the The combined beams emitted by the linear array semiconductor lasers have the same optical path and the same beam distribution characteristics when they reach the transformation transmission lens; the combined laser units overlap in space due to the effect of the diffraction grating and the output coupling mirror. After beam combining, the beam quality in the direction of the fast axis remains unchanged, and the quality of the beam in the direction of the slow axis is reduced to that of a single laser unit, thereby improving the beam quality of the output beam, and due to the increase in the number of linear array semiconductor lasers, the output The laser power density and brightness are N times higher than that of a single laser unit (N is the number of laser units in the beam combining direction).

In the second exemplary embodiment of the present disclosure, a multi-line array semiconductor laser grating external cavity spectral beam combining method is provided. The linear array semiconductor lasers are placed on the copper block, along the horizontal direction The left and right sides are placed and arranged at equal intervals along the x and y directions, and the height difference of the copper blocks is used in the vertical direction for equal height difference arrangement. The method includes:

A plurality of linear array semiconductor lasers emit light, which is collimated sequentially through a slow-axis collimator mirror and a fast-axis collimator mirror;

The light beams collimated by the fast and slow axes are reflected by the triangular prism and output as a series of parallel and equally spaced combined light beams;

The combined light beams are combined by the conversion lens to form a converging light beam, which is incident on the diffraction grating at different angles;

converging the light beams and completely overlapping at the diffraction grating, diffracted by the diffraction grating to the coupling output mirror;

Reflected by the coupling output mirror, the light beam fed back to the linear array semiconductor laser forms a stable oscillation.

After the linear array semiconductor laser is diffracted by the diffraction grating and combined with the feedback of the coupling output mirror, the beam quality in the fast axis direction remains unchanged, and the beam quality in the slow axis direction is reduced to the beam quality of a single laser unit, thereby improving Beam quality and power density of the output beam.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that, in the accompanying drawings or in the text of the specification, implementations that are not shown or described are forms known to those of ordinary skill in the art, and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those skilled in the art can easily modify or replace them.

It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only referring to the directions of the drawings, not Used to limit the protection scope of this disclosure. Throughout the drawings, the same elements are indicated by the same or similar reference numerals. Conventional structures or constructions are omitted when they may obscure the understanding of the present disclosure.

And the shape and size of each component in the figure do not reflect the actual size and proportion, but only illustrate the content of the embodiment of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Unless known to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties obtained from the teachings of the present disclosure. Specifically, all numbers used in the specification and claims to represent the content of components, reaction conditions, etc. should be understood to be modified by the term "about" in all cases. In general, the expressed meaning is meant to include a variation of ±10% in some embodiments, a variation of ±5% in some embodiments, a variation of ±1% in some embodiments, a variation of ±1% in some embodiments, and a variation of ±1% in some embodiments ±0.5% variation in the example.

Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Words such as "first", "second", "third" and the like used in the description and claims to modify the corresponding elements do not in themselves mean that the elements have any ordinal numbers, nor The use of these ordinal numbers to represent the sequence of an element with respect to another element, or the order of manufacturing methods, is only used to clearly distinguish one element with a certain designation from another element with the same designation.

In addition, unless specifically described or steps that must occur sequentially, the order of the above steps is not limited to that listed above and may be changed or rearranged according to the desired design. Moreover, the above-mentioned embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, technical features in different embodiments can be freely combined to form more embodiments.

Those skilled in the art can understand that the modules in the device in the embodiment can be adaptively changed and arranged in one or more devices different from the embodiment. Modules or units or components in the embodiments may be combined into one module or unit or component, and furthermore may be divided into a plurality of sub-modules or sub-units or sub-assemblies. All features disclosed in this specification (including accompanying claims, abstract and drawings) and any method or method so disclosed may be used in any combination, except that at least some of such features and/or processes or units are mutually exclusive. All processes or units of equipment are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Moreover, in a unit claim enumerating several means, several of these means may be embodied by the same item of hardware.

Similarly, it should be appreciated that in the above description of exemplary embodiments of the disclosure, in order to streamline the disclosure and to facilitate an understanding of one or more of the various disclosed aspects, various features of the disclosure are sometimes grouped together into a single embodiment, figure, or its description. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above descriptions are only specific embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims (10)

1. A multi-linear semiconductor laser grating external cavity spectral beam combining system, comprising: Multiple beam combining units, including: A plurality of linear array semiconductor lasers are arranged at equal intervals along the x direction and the y direction on the horizontal plane; A collimation unit is arranged in front of the linear array semiconductor laser to obtain a collimated light beam along the fast and slow axes; Triangular prisms are arranged in front of each beam combining unit to reflect the beams; The transformation transmission lens is arranged on the outgoing direction of the light beam after passing through the prism, and the combined light beam emitted by the beam combining unit becomes a converging light beam after passing through the transformation transmission lens, and the convergence point is a; The diffraction grating is arranged at the converging point a of the combined beam, and the convergent beam passes through the diffraction grating to generate a diffracted beam; The coupling output mirror is arranged in the direction of the diffracted beam of the vertical axis beam, reflects the diffracted beam perpendicularly incident on it, and feeds back the beam of the linear array semiconductor laser to form a stable oscillation. 2. The multi-linear array semiconductor laser grating external cavity spectral beam combining system according to claim 1, wherein said linear array semiconductor lasers are arranged along the left and right sides with a plurality of triangular prisms as symmetry axes in the horizontal direction. 3. The multi-linear array semiconductor laser grating external cavity spectral beam combining system according to claim 2, wherein said linear array semiconductor lasers are arranged with equal height difference in the vertical z direction. 4. according to the multi-line array semiconductor laser grating external cavity spectral beam combination method described in any one of claims 1 to 3, a column of parallel and equally spaced combined light beams output after reflection by the triangular prism arrives at the conversion lens The optical path lengths are equal. 5. The multi-linear array semiconductor laser grating external cavity spectrum beam combining system according to any one of claims 1 to 3, the collimation unit comprising: The slow axis collimating mirror is arranged in front of each of the linear array semiconductor lasers, and is used to reduce the divergence angle of the light beam in the direction of the slow axis; A fast-axis collimator, arranged in front of each slow-axis collimator, is used to reduce the divergence angle of the light beam in the fast-axis direction. 6. The multi-linear array semiconductor laser grating external cavity spectrum beam combining system according to claim 5, wherein the fast axis collimator is a cylindrical microlens, and the slow axis collimator is a cylindrical microlens array. 7. The multi-linear array semiconductor laser grating external cavity spectral beam combining system according to any one of claims 1 to 3, wherein the reflectance R of the reflective film coated on the triangular prism is >99%. 8. The multi-linear array semiconductor laser grating external cavity spectral beam combining system according to any one of claims 1 to 3, wherein the outcoupling mirror is a flat mirror, and the reflective film coated has a reflectivity of 10%. 9. A method for multi-linear semiconductor laser grating external cavity spectral beam combining, using the multi-linear semiconductor laser grating external cavity spectral beam combining system as claimed in any one of claims 1-8, comprising: Multiple linear array semiconductor lasers emit light, which are collimated by collimating units in sequence; The light beams collimated by the fast and slow axes are reflected by the triangular prism and output as a series of parallel and equally spaced combined light beams; The combined beams are combined by the transformation lens into a converging beam, which is incident on the diffraction grating at different angles; converging the light beams and completely overlapping at the diffraction grating, diffracted by the diffraction grating to the coupling output mirror; Reflected by the coupling output mirror, the light beam fed back to the linear array semiconductor laser forms a stable oscillation. 10. The multi-linear array semiconductor laser grating external cavity spectral beam combining method according to claim 9, wherein, after the linear array semiconductor laser is diffracted by the diffraction grating and combined with the feedback of the coupling output mirror, the fast axis direction The beam quality remains the same, the beam quality in the slow axis direction is reduced to the beam quality of a single laser unit, and the output laser power density and brightness are increased to N times that of a single laser unit, where N is the number of laser units in the direction of spectral beam combining.