WO2017197883A1

WO2017197883A1 - Laser array beam combining device

Info

Publication number: WO2017197883A1
Application number: PCT/CN2016/111710
Authority: WO
Inventors: 张哨峰; 李大汕; 杨金涛; 沈渊; 孙晓斌
Original assignee: 上海高意激光技术有限公司
Priority date: 2016-05-18
Filing date: 2016-12-23
Publication date: 2017-11-23
Also published as: CN105811245A

Abstract

A laser array beam combining device, comprising: a laser gain medium array (1) comprising at least two laser gain elements (11, 12, 13), each of which can generate a laser beam having a particular spectrum width; a shaping optical system (2) for collimating each laser beam generated by the laser gain medium array (1) to obtain a group of parallel collimated laser beam arrays; a dispersing optical component for performing diffraction or refraction on the incident collimated laser beam arrays at least twice, and then combining the beams and outputting the combined beams; and a partial reflecting optical element (4) for receiving the combined laser beams and emitting the laser beams.

Description

Laser array combining device

The present application claims the priority of the Chinese invention patent application (application number: 201610329813.4; invention name: a laser array combining device; application date: May 18, 2016), the entire contents of which are hereby incorporated by reference. All incorporated herein.

Technical field

The invention relates to the field of lasers, in particular to a spectrally overlapping external cavity laser array combining device.

Background technique

Semiconductor lasers are characterized by high efficiency, small size, wide wavelength range, low cost, high reliability, etc., which are attractive compared to other lasers. However, the output beam quality of semiconductor lasers is poor, and the power level of a single laser is limited, which hinders the expansion of its application range.

In recent years, with the development of semiconductor laser technology, and driven by direct semiconductor laser industrial processing applications and high-power fiber laser pumping demand, semiconductor lasers with high power and high beam quality have developed rapidly. At the same time, laser beam combining technology has led to a doubling of laser power over the past few years. At present, the power levels of fiber lasers and direct semiconductor lasers using the combining technology have reached the order of kilowatts.

At present, more in the field of direct semiconductor lasers is the non-coherent beam combining technology. The method is such that the output lasers of the plurality of lasers propagate in the same direction, so that the power of the laser can be multiplied, and the power level is proportional to the number of lasers. Incoherent combining techniques include spatial combining, polarization combining, and wavelength combining.

A space commissing technique, such as that described in U.S. Patent No. 6,124,973, by the disclosure of a plurality of semiconductor lasers in a spatial order in a certain order, forming a group of laser beams propagating in the same direction. Thereby obtaining a high power laser output. Since space stacking cannot improve beam quality, the resulting high-power laser output is generally applied directly to applications where beam quality is not critical, such as pumping sources for fiber lasers.

The polarization combining technique is based on the polarization characteristics of the laser, and the two lasers having different polarization directions are combined and propagated in the same direction, for example, as described in U.S. Patent No. 8,427,749. Generally, the polarization combining technique combines laser beam or laser beam combination in which two polarization directions are perpendicular to each other, and is always used in combination with other combining techniques.

Wavelength combining technology combines laser beams of different wavelengths through optical components such as dichroic mirrors and gratings to effectively improve power and brightness. It is the main direction of the development of high-power direct semiconductor lasers. For example, a VBG bulk Bragg grating is used to multiplex multiple lasers with different wavelengths as described by Armen Sevian et al. in Efficient power scaling of laser radiation by spectral beam combining (OPTICS LETTERS/Vol. 33, No. 4/February 15, 2008). Synthesize a bunch. An external cavity semiconductor laser array combining scheme based on a diffraction grating is described by Antonio Sanchez-Rubio et al. in U.S. Patent No. 6,192,062, which has developed a high power, high beam. High-quality, high-brightness direct semiconductor lasers have driven applications in laser processing.

The current wavelength combining technique, whether using a dichroic mirror, a bulk Bragg grating or a diffraction grating, is always limited by the spectrum, and different wavelengths are required to be independent of each other, and a sufficient wavelength interval is required.

The spectral sum of the external cavity semiconductor laser array based on U.S. Patent No. 6,192,062 and the like is narrow, and the spectrum of the single laser is narrow; and because the overall optical path is relatively difficult to adjust, the stability is high; the type of the combined laser The final output spectrum is generally wider to achieve higher output power, which is inconvenient for the continued expansion of the direct output semiconductor laser power.

Summary of the invention

In view of the deficiencies in the prior art, it is an object of the present invention to provide a laser array combining device that improves the quality of the laser beam and allows the spectra of the respective laser gain elements to overlap.

According to an aspect of the invention, there is provided a laser array combining device comprising: a laser gain medium array, the laser gain medium array comprising at least two laser gain elements, each of the laser gain elements A laser beam can be generated; an shaping optical system collimating each of the laser beams generated by the laser gain medium array to obtain a set of parallel collimated laser beam arrays; a dispersive optical component, The collimated laser beam array performs a second diffraction or a refracted combined output; the partially reflective optical element receives the combined laser beam and emits it.

Preferably, the dispersive optical component performs a second diffraction or a refracted combined output on the incident collimated laser beam array, the dispersive optical component comprising: a first dispersive optical element, the incident collimated laser The beam array is diffracted or refracted; the second dispersive optical element receives the array of collimated laser beams diffracted or refracted by the first dispersive optical element, and the collimated laser beam array is diffracted or refracted; The array of collimated laser beams diffracted or refracted by the first dispersive optical element coincides at the second dispersive optical element; the partially reflective optical element receives diffraction or refraction by the second dispersive optical element After the laser beam.

Preferably, the first dispersive optical element is a first prism, the second dispersive optical element is a second prism, and the first prism and the second prism are two identical prisms.

Preferably, the exit surface of the first prism is parallel to the incident surface of the second prism in the outgoing direction of the laser beam.

Preferably, the first dispersive optical element and the second dispersive optical element are a pair of diffraction gratings.

Preferably, the grating faces of the pair of diffraction gratings are parallel to each other and have the same grating period.

Preferably, the diffraction grating is a transmissive grating or a reflective grating.

Preferably, the dispersive optical component performs a second diffraction or a refracted beam output on the incident collimated laser beam array, the dispersive optical component comprising: a third dispersive optical element, the incident collimated laser The beam array is diffracted or refracted; the reflective prism has a plurality of reflecting surfaces, and the reflecting prism reflects the array of collimated laser beams diffracted or refracted by the third dispersive optical element back to the third dispersive optical element, Having the array of collimated laser beams diffracted or refracted by the third dispersive optical element; wherein the collimation is reflected by the reflective prism An array of light beams coincides at the third dispersive optical element; the partially reflective optical element receives a laser beam that is again diffracted or refracted by the third dispersive optical element.

Preferably, the third dispersive optical element is a diffraction grating or a prism.

Preferably, the third dispersive optical element is a transmissive grating or a reflective grating.

Preferably, the shaping optical system comprises: a first collimating mirror that receives a laser beam generated by the laser gain element and emits the laser beam; and a second collimating mirror that receives the laser beam emitted by the first collimating mirror And direct it toward the dispersive optical component.

Preferably, the first collimating mirror is a fast axis collimating mirror, and the second collimating mirror is a slow axis collimating mirror.

Preferably, the laser gain medium array is a semiconductor laser array.

Preferably, in the laser gain medium array, spectra of laser beams generated by two adjacent laser gain elements partially overlap.

Preferably, the partially reflective optical element is a mirror coated with a dielectric film.

Preferably, the exit direction of the partially reflective optical element and the exit direction of the shaping optical system are parallel to each other.

The embodiment of the invention discloses a laser array combining device, wherein the dispersive optical component of the laser array combining device uses two dispersive optical elements or a dispersive optical element and a reflecting prism to make the laser beam array pass through the dispersive optical component. Two diffractions or refractions are used to achieve the combination of the laser beams generated by the respective laser gain elements, and the dispersion optical components can effectively improve the quality of the laser beam on the one hand, and the spectra of the respective laser gain elements can overlap to form a combination The spectrum after the narrowing. In addition, the laser beam of each laser gain element is collimated by the shaping optical system prior to passing through the dispersive optical assembly, and thus the laser array combining device can also reduce the size requirements for the dispersive optical assembly.

DRAWINGS

1 is a schematic structural view of a laser array combining device according to a first embodiment of the present invention;

2 is a schematic structural view of a laser array combining device according to a second embodiment of the present invention;

Fig. 3 is a schematic structural view of a laser array combining device according to a third embodiment of the present invention.

detailed description

According to the gist of the present invention, the laser array combining device comprises: a laser gain medium array, the laser gain medium array comprising at least two laser gain elements, each of the laser gain elements capable of generating a laser having a certain spectral width a shaping optical system for collimating each of the laser beams generated by the laser gain medium array to obtain a set of mutually parallel collimated laser beam arrays; a dispersive optical component for the incident collimated laser beam array The second diffraction or the refracted combined output is performed; the partially reflective optical element receives the combined laser beam and emits it.

The technical content of the present invention will be further described below with reference to the accompanying drawings and embodiments.

First embodiment

Referring to FIG. 1, there is shown a schematic structural view of a laser array combining device of a first embodiment of the present invention. In the picture In a preferred embodiment shown in FIG. 1, the laser array combining device comprises: a laser gain medium array 1, an shaping optical system 2, a dispersive optical component, and a partially reflective optical element 4.

The laser gain medium array 1 includes at least two laser gain elements, each of which is capable of generating a laser beam having a certain spectral width. In the embodiment shown in Figure 1, the laser gain medium array 1 is preferably a semiconductor laser array. The laser gain medium array 1 includes a plurality of laser gain elements. It should be noted that only the first laser gain element 11, the second laser gain element 12, and the third laser gain element 13 are schematically illustrated in FIG. 1, wherein The three laser gain elements 13 are one laser gain element spaced apart from the second laser gain element 12 by n laser gain elements, and n laser gains between the second laser gain element 12 and the third laser gain element 13 are omitted in FIG. element. In the laser gain medium array 1, the spectral portions of the laser beams generated by the adjacent two of the laser gain elements partially overlap. For example, in the embodiment shown in FIG. 1, the first laser gain element 11 and the second laser gain element 12 partially overlap the spectrum of the laser beam produced by the second laser gain element 12.

The shaping optical system 2 collimates each of the laser beams generated by the laser gain medium array 1 to obtain a set of mutually parallel collimated laser beam arrays. Specifically, as shown in FIG. 1, the shaping optical system 2 includes a first collimating mirror 21 and a second collimating mirror 22. The first collimator 21 receives the laser beam generated by the laser gain element 1 and emits it. The second collimating mirror 22 receives the laser beam emitted from the first collimating mirror 21 and then directs it to the dispersive optical component. In the embodiment shown in FIG. 1, the first collimating mirror 21 is a fast axis collimating mirror and the second collimating mirror 22 is a slow axis collimating mirror.

The dispersive optical component performs a second diffraction or refracted beam output on the incident collimated laser beam array emitted by the shaping optical system 2. In the embodiment illustrated in FIG. 1, the dispersive optical assembly performs a second diffraction or refracted beam output on the incident array of collimated laser beams. In particular, the dispersive optical component includes a first dispersive optical element 31 and a second dispersive optical element 32. Wherein, the first dispersive optical element 31 diffracts or refracts the incident collimated laser beam array. The second dispersive optical element 32 receives the collimated laser beam array diffracted or refracted by the first dispersive optical element, and the collimated laser beam array is again diffracted or refracted. The collimated laser beam array emitted by the shaping optical system 2 is diffracted or refracted by the first dispersive optical element 31 and then overlapped at the second dispersive optical element 32. In the embodiment shown in FIG. 1, the first dispersive optical element 31 is a first prism, and the second dispersive optical element 32 is a second prism, that is, the first dispersive optical element 31 and the second dispersive optical element 32 are a set of prisms. Yes, wherein the first prism and the second prism may be two identical prisms. Preferably, the exit surface 311 of the first prism 31 is parallel to the incident surface 321 of the second prism 32 in the outgoing direction of the laser beam of the collimated laser beam array. It should be noted that the exit surface 311 of the first prism 31 herein refers to the exit surface of the first prism 31 in the process of being diffracted or refracted by the first prism 31 and directed to the second prism 32. It can be understood that The exit surface 311 of a prism 31 is the incident surface of the first prism 31 in the process in which the shaping optical system 2 directs the collimated laser beam array toward the first prism 31. Similarly, the incident surface 321 of the second prism 32 herein refers to the incident surface of the second prism 32 in the process in which the collimated laser beam array is diffracted or refracted by the first prism 31 and directed toward the second prism 32, which is understandable. That is, the incident surface 321 of the second prism 32 is also the exit surface of the second prism 32 in the process of the diffracted laser beam array being diffracted or refracted by the second prism 32 toward the partially reflective optical element 4.

The partially reflective optical element 4 receives the laser beam combined by the dispersive optical component and emits it. Specific That is, in the embodiment shown in Fig. 1, the partially reflective optical element 4 receives the laser beam diffracted or refracted by the second dispersive optical element 32, and partially emits the laser beam. The outgoing direction of the partially reflective optical element 4 and the outgoing direction of the shaping optical system 2 are parallel to each other. Preferably, the partially reflective optical element 4 is a mirror plated with a dielectric film.

In this embodiment, the dispersive optical component of the laser array combining device uses two dispersive optical elements to cause the laser beam array to be diffracted or refracted twice to achieve the combination of the laser beams generated by the respective laser gain elements. On the one hand, the dispersive optical component can effectively improve the beam quality, and on the other hand, the spectrum of each laser gain element can overlap, and the spectrum after the combination is narrowed. In addition, the laser beam of each laser gain element is collimated by the shaping optical system prior to passing through the dispersive optical assembly, and thus the laser array combining device can also reduce the size requirements for the dispersive optical assembly.

Second embodiment

Referring to FIG. 2, there is shown a schematic structural view of a laser array combining device of a second embodiment of the present invention. Different from the first embodiment shown in Fig. 1 described above, in this embodiment, the first dispersive optical element and the second dispersive optical element are a pair of diffraction gratings. The first dispersive optical element and the second dispersive optical element replace the prism pair in the first embodiment described above by using a pair of diffraction gratings. Specifically, as shown in Fig. 2, the first dispersive optical element 31' and the second dispersive optical element 32' are a pair of diffraction gratings. The diffraction grating may be a transmissive grating or a reflective grating. Preferably, the grating faces of the pair of diffraction gratings are parallel to each other and have the same grating period. This embodiment can achieve effects similar to those of the first embodiment described above, and will not be described herein.

Third embodiment

Referring to FIG. 3, there is shown a schematic structural view of a laser array combining device of a third embodiment of the present invention. Different from the first embodiment and the second embodiment shown in FIGS. 1 and 2 above, in this embodiment, the dispersive optical component includes a third dispersive optical element and a reflective prism. The dispersive optical component replaces the first dispersive optical element and the second dispersive optical element described above by using the third dispersive optical element and the reflective prism. Specifically, as shown in FIG. 3, the dispersive optical component includes a third dispersive optical element 33 and a reflective prism 34. The third dispersion optical element 33 diffracts or refracts the array of collimated laser beams incident by the shaping optical system 2. In the embodiment shown in Figure 3, the third dispersive optical element 33 is a diffraction grating or a prism. More preferably, the third dispersive optical element 33 is a transmissive grating or a reflective grating. The reflecting prism 34 has a plurality of reflecting surfaces that reflect the array of collimated laser beams diffracted or refracted by the third dispersive optical element 33 back to the third dispersive optical element 33, so that the collimated laser beam array is thirdly dispersed The optical element 33 is again diffracted or refracted. The array of collimated laser beams reflected by the reflecting prism 34 coincides at the third dispersive optical element 33. The partially reflective optical element 4 receives the laser beam that is diffracted or refracted by the third dispersive optical element 33 again. It should be noted that, in this embodiment, the array of collimated laser beams emitted by the shaping optical system 2 is combined by two diffractions or refractions of the third dispersive optical element 33, thereby achieving the first implementation described above. Similar effects of the example and the second embodiment will not be described herein.

In summary, the embodiment of the present invention discloses a laser array combining device, wherein the dispersive optical component of the laser array combining device uses two dispersive optical elements or a dispersive optical element and a reflective prism to form a laser beam array. The diffractive optical component is diffracted or refracted twice to achieve the combination of the laser beams generated by the respective laser gain elements. The dispersive optical component can effectively improve the quality of the laser beam on the one hand, and the spectrum of each laser gain component can be By overlapping, the spectrum after the combination is narrowed. In addition, the laser beam of each laser gain element is collimated by the shaping optical system prior to passing through the dispersive optical assembly, and thus the laser array combining device can also reduce the size requirements for the dispersive optical assembly.

Although the invention has been disclosed above in the preferred embodiments, it is not intended to limit the invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the claims.

Claims

A laser array combining device, characterized in that the laser array combining device comprises:

a laser gain medium array, the laser gain medium array comprising at least two laser gain elements, each of the laser gain elements capable of generating a laser beam;

Forming an optical system for collimating each of the laser beams generated by the laser gain medium array to obtain a set of parallel collimated laser beam arrays;

a dispersive optical component for performing second-order diffraction or refraction of the incident collimated laser beam array;

The partially reflective optical element receives the combined laser beam and emits it.
The laser array combining device according to claim 1, wherein the dispersive optical component performs a second diffraction or a refracted beam output on the incident collimated laser beam array, and the dispersive optical component comprises:

a first dispersive optical element that diffracts or refracts the incident array of collimated laser beams;

a second dispersive optical element receiving the collimated laser beam array diffracted or refracted by the first dispersive optical element, and the collimated laser beam array is diffracted or refracted;

Wherein the array of collimated laser beams diffracted or refracted by the first dispersive optical element coincides at the second dispersive optical element; the partially reflective optical element receives diffraction by the second dispersive optical element or The refracted laser beam.
The laser array combining device according to claim 2, wherein said first dispersive optical element is a first prism, said second dispersive optical element is a second prism, said first prism and said first The prism is two identical prisms.
The laser array compositing apparatus according to claim 3, wherein an exit surface of the first prism is parallel to an incident surface of the second prism in an outgoing direction of the laser beam.
The laser array combining apparatus according to claim 2, wherein said first dispersive optical element and said second dispersive optical element are a pair of diffraction gratings.
The laser array combining apparatus according to claim 5, wherein the grating faces of the pair of diffraction gratings are parallel to each other and have the same grating period.
The laser array combining device according to claim 6, wherein the diffraction grating is a transmissive grating or a reflective grating.
The laser array combining device according to claim 1, wherein the dispersive optical component performs a second diffraction or a refracted beam output on the incident collimated laser beam array, and the dispersive optical component comprises:

a third dispersion optical element that diffracts or refracts the incident array of collimated laser beams;

a reflective prism having a plurality of reflective surfaces, the reflective prism reflecting the array of collimated laser beams diffracted or refracted by the third dispersive optical element back to the third dispersive optical element to cause the collimated laser beam The array is again diffracted or refracted by the third dispersive optical element;

Wherein the array of collimated laser beams reflected by the reflective prism coincides at the third dispersive optical element; the partially reflective optical element receives laser light that is diffracted or refracted by the third dispersive optical element again bundle.
The laser array combining device according to claim 8, wherein the third dispersion optical element is a diffraction grating or a prism.
The laser array combining device according to claim 9, wherein the third dispersive optical element is a transmissive grating or a reflective grating.
The laser array combining device according to any one of claims 1 to 10, wherein the shaping optical system comprises:

a first collimating mirror that receives a laser beam generated by the laser gain element and emits it;

The second collimating mirror receives the laser beam emitted by the first collimating mirror and then directs it to the dispersive optical component.
The laser array combining device according to claim 11, wherein the first collimating mirror is a fast axis collimating mirror, and the second collimating mirror is a slow axis collimating mirror.
The laser array combining device according to any one of claims 1 to 10, wherein the laser gain medium array is a semiconductor laser array.
The laser array combining apparatus according to any one of claims 1 to 10, wherein in the laser gain medium array, spectral bands of laser beams generated by two adjacent laser gain elements partially overlap.
The laser array combining device according to any one of claims 1 to 10, wherein the partially reflective optical element is a mirror plated with a dielectric film.
The laser array combining device according to any one of claims 1 to 10, wherein an outgoing direction of the partially reflective optical element and an outgoing direction of the shaping optical system are parallel to each other.