A multi-channel laser synthetic aperture emission system

Abstract

The present invention discloses a multi-channel laser synthetic aperture emission system, including a fiber laser system, a polarization beam combiner system, a beam combiner system, and a Cassegrain beam expansion system. The fiber laser system is composed of six fiber lasers, and the polarization beam combiner system is composed of three polarization beam combiners (PBCs). The same wavelength light emitted by the six fiber lasers is synthesized and polarized by the polarization beam combiners (PBCs) in pairs to obtain three parallel high-power coherent polarization composite light beams. The beam combiner system then forms a triangular annular aperture laser beam, which is finally reflected by the Cassegrain beam expansion system. The multi-channel laser synthetic aperture emission system of the present invention has a simple structure and a compact layout. It effectively breaks through the power limit of a single-channel fiber laser output through the coherent polarization synthesis technology. The three-channel laser is combined by the beam combiner system. The beam combining method is simple and easy to implement. The combined beam power is high, the quality is high, the cost is low, and the stability is good.

Description

Technical Field

[0001] The present invention relates to the technical field of optical applications, and in particular to a multi-path laser synthetic aperture emission system. Background Art

[0002] Fiber lasers are increasingly favored by laser system integrators due to their high efficiency and low maintenance costs. They have already replaced or are replacing C02 lasers and other solid-state lasers in many applications, revolutionizing the laser market and driving its continued development. Laser beam combining is a key technology that enables high-power, high-energy laser output from semiconductor lasers. It utilizes optical properties such as laser phase, light field distribution, polarization, and spectrum to combine multiple low-power unit beams into a high-power laser output through optical effects such as refraction, reflection, and diffraction, while maintaining high beam quality. This significantly increases the energy and power of the semiconductor laser's output beam.

[0003] Laser beam expansion structures include Galilean and Keplerian configurations, both of which epitomize telescope structures. Depending on the application and beam expansion requirements, beam expansion systems can employ refractive, reflective, or a combination of catadioptric and reflective optical structures. Refractive structures are simpler in design and relatively easy to manufacture and assemble, but they have smaller practical apertures. Reflective structures are more commonly used for larger apertures. For beam expansion structures that can utilize multiple laser wavelengths, chromatic aberration is the most problematic issue. Transmissive structures must employ apochromatic structures to correct for chromatic aberration, which results in an increased number of mirrors and higher mass. Reflective structures, lacking chromatic aberration, are well-suited for multi-wavelength applications. With advancements in aspheric surface processing, transflective structures are gaining increasing attention and application, and their cost is also decreasing. High-performance laser beam expansion systems generally utilize Cassegrain telescopes.

[0004] The lasers currently used in research both domestically and internationally include fiber lasers, semiconductor-pumped solid-state lasers, free electron lasers, and liquid lasers. Fiber lasers, with their advantages of high conversion efficiency, compact structure, high beam quality, and convenient thermal management, have become the preferred laser light source in recent years. Due to nonlinear and thermal effects, a single optical fiber has a limit on its output power, and it is difficult to ensure beam quality at high power. Furthermore, these issues include high cost and complex structure. If a single fiber laser fails, the system will not function. Furthermore, insufficient output power from a single fiber laser can easily lead to problems with short emission distances and low energy in laser beam expansion systems. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-channel laser synthetic aperture emission system and a detection method thereof to solve the above defects.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A multi-channel laser synthetic aperture emission system includes a fiber laser system, a polarization beam combiner system, a beam combiner system, and a Cassegrain beam expansion system. The fiber laser system is composed of six fiber lasers, and the polarization beam combiner system is composed of three polarization beam combiners (PBCs). Light of the same wavelength emitted by the six fiber lasers is synthesized and polarization-controlled in pairs by the polarization beam combiners (PBCs) to obtain three parallel-arranged high-power coherent polarization composite light beams. The three beams are then formed into triangular annular aperture laser beams by the beam combiner system and finally reflected out by the Cassegrain beam expansion system.

[0008] Preferably, the six fiber lasers are fiber laser 1, fiber laser 2, fiber laser 3, fiber laser 4, fiber laser 5, and fiber laser 6, and the three polarization beam combiners PBC are PBC 1, PBC 2, and PBC 3, respectively. The light of the same wavelength emitted by the fiber laser 2 is reflected by the total reflection mirror 1, and then synthesized and polarized controlled with the light of the same wavelength emitted by the fiber laser 1 by PBC 1 to obtain a high-power coherent polarization synthesized beam 1; the light of the same wavelength emitted by the fiber laser 4 is reflected by the total reflection mirror 2, and then synthesized and polarized controlled with the light of the same wavelength emitted by the fiber laser 3 by PBC 2 to obtain a high-power coherent polarization synthesized beam 2; the light of the same wavelength emitted by the fiber laser 6 is reflected by the total reflection mirror 3, and then synthesized and polarized controlled with the light of the same wavelength emitted by the fiber laser 5 by PBC 3 to obtain a high-power coherent polarization synthesized beam 3; the coherent polarization synthesized beam 1, the coherent polarization synthesized beam 2, and the coherent polarization synthesized beam 3 are arranged in parallel.

[0009] Preferably, the beam combining mirror system includes a total reflector four, a total reflector five, a total reflector six, a total reflector seven, a total reflector eight, and a total reflector nine, and the total reflector four and the total reflector five, the total reflector six and the total reflector seven, and the total reflector eight and the total reflector nine are parallel to each other in pairs; the coherent polarized synthetic beam one is reflected in turn by the total reflector four and the total reflector five, the coherent polarized synthetic beam two is reflected in turn by the total reflector six and the total reflector seven, and the coherent polarized synthetic beam three is reflected in turn by the total reflector eight and the total reflector nine to form a triangular annular aperture laser beam.

[0010] Preferably, the Cassegrain beam expander system consists of a primary mirror and a secondary mirror of a reflecting parabola. The triangular annular aperture light beam is obliquely incident on the total reflection mirror ten, reflected by the total reflection mirror ten, and then collimated and emitted to the secondary mirror of the Cassegrain beam expander system, and then reflected from the secondary mirror to the primary mirror, and finally reflected by the primary mirror out into the air.

[0011] Preferably, the fully reflective mirror one, fully reflective mirror two, fully reflective mirror three, fully reflective mirror four, fully reflective mirror five, fully reflective mirror six, fully reflective mirror seven, fully reflective mirror eight, fully reflective mirror nine, fully reflective mirror ten, and the primary mirror and secondary mirror of the Cassegrain beam expander system are all coated with an optical reflective film, and the reflectivity is greater than 99%.

[0012] Preferably, the primary mirror is a concave secondary aspheric reflector, and the secondary mirror is a convex secondary aspheric reflector.

[0013] Preferably, the surface shape formulas of the primary mirror and the secondary mirror are:

[0014]

[0015] Where c is the vertex curvature and k is the quadratic constant.

[0016] Preferably, the primary mirror is simulated and designed using optical design software Zemax, and the parameters of the primary mirror are: vertex curvature radius R1 = 3000 mm; cone coefficient K = -1; effective aperture is Φ950 mm; material is microcrystalline glass; focal length is 1500 mm; coating is a dielectric high-reflection film with a reflectivity of >99%@1083 nm; surface quality is: RMS≤λ / 30, λ=632.8 nm.

[0017] Preferably, the secondary mirror is simulated and designed using the optical design software ZEMAX, and the parameters of the secondary mirror are: secondary mirror vertex curvature radius R0 = 108 mm; cone coefficient K = -1; effective aperture is Φ34.2 mm; material is microcrystalline glass; focal length is 54 mm; coating is a dielectric high-reflection film with a reflectivity of >99%@1083 nm; surface quality is: RMS≤λ / 30, λ = 632.8 nm.

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides a multi-channel laser synthetic aperture emission system with a simple structure and compact layout. Through coherent polarization synthesis technology, it effectively overcomes the power limitations of single-channel fiber laser output, providing an effective way to achieve higher power and higher beam quality output. The present invention uses a beam combining mirror system to combine three laser channels. This simple and easy-to-implement beam combining method achieves high combined power and quality. The present invention avoids the need for the same number of laser beam expanders as fiber lasers, instead utilizing only one Cassegrain beam expander system, addressing issues such as high system cost and complex structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : Optical system diagram of the multi-channel laser synthetic aperture emission system of the present invention;

[0021] Figure 2 : Six-way laser synthetic aperture optical path diagram of the present invention;

[0022] Figure 3 : Optical system diagram of the Cassegrain beam expansion system of the present invention. DETAILED DESCRIPTION

[0023] Combined with attachment Figure 1-3 , the specific embodiments of the present invention are described as follows:

[0024] like Figure 1 、 2 As shown in Figure 3, a multi-channel laser synthetic aperture emission system includes a fiber laser system, a polarization beam combiner system, a beam combiner system, and a Cassegrain beam expander system. The fiber laser system is composed of six fiber lasers, and the polarization beam combiner system is composed of three polarization beam combiners PBC. The same wavelength light emitted by the six fiber lasers is synthesized and polarization controlled by the three polarization beam combiners PBC in pairs to obtain three parallel arranged high-power coherent polarization synthetic light beams, which are then formed into triangular annular aperture laser beams through the beam combiner system and finally reflected out by the Cassegrain beam expander system.

[0025] The six fiber lasers are equidistantly arranged in parallel and emit light of the same wavelength. The three polarization beam combiners (PBCs) are PBC-1 (21), PBC-2 (22), and PBC-3 (23), capable of controlling the polarization of the two beams. The light of the same wavelength emitted by fiber laser 2 12 is reflected by total reflection mirror 1 31 and then combined with the light of the same wavelength emitted by fiber laser 1 11 via PBC 1 21 and polarization control to produce a high-power coherent polarization composite beam 1. Simultaneously, the light of the same wavelength emitted by fiber laser 4 14 is reflected by total reflection mirror 2 32 and then combined with the light of the same wavelength emitted by fiber laser 3 13 via PBC 2 22 and polarization control to produce a high-power coherent polarization composite beam 2. The light of the same wavelength emitted by fiber laser 6 16 is reflected by total reflection mirror 3 33 and then combined with the light of the same wavelength emitted by fiber laser 5 15 via PBC 3 23 and polarization control to produce a high-power coherent polarization composite beam 3. Furthermore, the coherent polarization composite beams 1, 2, and 3 are arranged in parallel.

[0026] The beam combining mirror system includes a total reflection mirror 4 34, a total reflection mirror 5 35, a total reflection mirror 6 36, a total reflection mirror 7 37, a total reflection mirror 8 38, and a total reflection mirror 9 39. Mirrors 4 34 and 5 35, mirrors 6 36 and 7 37, and mirrors 8 38 and 9 39 are all parallel to each other. Coherent polarized composite beam 1 is sequentially reflected by mirrors 4 34 and 5 35, coherent polarized composite beam 2 is sequentially reflected by mirrors 6 36 and 7 37, and coherent polarized composite beam 3 is sequentially reflected by mirrors 8 38 and 9 39. The three beams form a triangular annular aperture laser beam.

[0027] The Cassegrain beam expander system consists of a primary mirror 41 and a secondary mirror 42 of a reflecting parabola. The triangular annular aperture light beam formed by the beam combining mirror system is obliquely projected onto the total reflection mirror 10 30. After being reflected by the total reflection mirror 10 30, it is collimated and emitted to the secondary mirror 42 of the Cassegrain beam expander system, and then reflected from the secondary mirror 42 to the primary mirror 41, and finally reflected by the primary mirror 41 into the air.

[0028] Among them, fully reflective mirror 1 31, fully reflective mirror 2 32, fully reflective mirror 3 33, fully reflective mirror 4 34, fully reflective mirror 5 35, fully reflective mirror 6 36, fully reflective mirror 7 37, fully reflective mirror 8 38, fully reflective mirror 9 39, fully reflective mirror 10 30, and the primary mirror 41 and secondary mirror 42 of the Cassegrain beam expander system are all coated with an optical reflective film, and the reflectivity is greater than 99%.

[0029] The primary mirror 41 is a concave secondary aspheric reflector, and the secondary mirror 42 is a convex secondary aspheric reflector. The surface formulas of the primary mirror 41 and the secondary mirror 42 are:

[0030]

[0031] Where c is the vertex curvature and k is the quadratic constant.

[0032] Both primary mirror 41 and secondary mirror 42 were simulated and designed using the optical design software Zemax. The parameters of primary mirror 41 are: vertex curvature radius R1 = 3000mm; conic coefficient K = -1; effective aperture Φ950mm; material is glass-ceramic; focal length 1500mm; coating is a dielectric high-reflection film with a reflectivity >99% @ 1083nm; surface quality: RMS ≤ λ / 30, λ = 632.8nm. The parameters of secondary mirror 42 are: vertex curvature radius R0 = 108mm; conic coefficient K = -1; effective aperture Φ34.2mm; material is glass-ceramic; focal length 54mm; coating is a dielectric high-reflection film with a reflectivity >99% @ 1083nm; surface quality: RMS ≤ λ / 30, λ = 632.8nm.

[0033] The present invention provides a multi-channel laser synthetic aperture emission system, which solves the problems of high system cost and complex structure in the prior art; solves the problem that the system cannot work when a single-channel fiber laser fails in the prior art; solves the technical cost problem of using multiple beam expansion emission devices with the same number of fiber lasers in the system; and solves the problem that the laser beam expansion system has a short emission distance and low energy due to insufficient output power of a single fiber laser in the system.

[0034] The multi-channel laser synthetic aperture emission system of the present invention first uses a polarization beam combiner system to combine six laser beams into three, then uses a beam combiner mirror system to combine the three combined beams, and then expands the combined beam. This method can effectively increase the power and energy of the emitted laser and is suitable for fields such as laser coherent synthesis and laser radar beam expansion systems.

[0035] The present invention provides a multi-channel laser synthetic aperture emission system with a simple structure and compact layout. Through coherent polarization synthesis technology, it effectively overcomes the power limitations of single-channel fiber laser output, providing an effective way to achieve higher power and higher beam quality output. The present invention uses a beam combining mirror system to combine three laser channels. This simple and easy-to-implement beam combining method achieves high combined power and quality. The present invention avoids the need for the same number of laser beam expanders as fiber lasers, instead utilizing only one Cassegrain beam expander system, addressing issues such as high system cost and complex structure.

[0036] The above description of the invention is illustrative in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A multi-channel laser synthetic aperture transmission system, characterized in that: The system comprises a fiber laser system, a polarization beam combiner system, a beam combiner system, and a Cassegrain beam expander system. The fiber laser system is composed of six fiber lasers, and the polarization beam combiner system is composed of three polarization beam combiners (PBCs). Light of the same wavelength emitted by the six fiber lasers is synthesized and polarization-controlled in pairs by the polarization beam combiners (PBCs) to obtain three parallel-arranged high-power coherent polarization composite beams. The beams are then formed into triangular annular aperture laser beams by the beam combiner system and finally reflected out by the Cassegrain beam expander system. The six fiber lasers are fiber laser 1 (11), fiber laser 2 (12), fiber laser 3 (13), fiber laser 4 (14), fiber laser 5 (15), and fiber laser 6 (16); the three polarization beam combiners (PBCs) are PBC 1 (21), PBC 2 (22), and PBC 3 (23); the same wavelength light emitted by fiber laser 2 (12) is reflected by total reflector 1 (31) and then synthesized and polarized controlled by PBC 1 (21) with the same wavelength light emitted by fiber laser 1 (11) to obtain a high-power coherent polarization synthesized beam 1; The same wavelength light emitted by the fiber laser four (14) is reflected by the total reflection mirror two (32), and then synthesized and polarized controlled with the same wavelength light emitted by the fiber laser three (13) by the PBC two (22) to obtain a high-power coherent polarization synthesized beam two; the same wavelength light emitted by the fiber laser six (16) is reflected by the total reflection mirror three (33), and then synthesized and polarized controlled with the same wavelength light emitted by the fiber laser five (15) by the PBC three (23) to obtain a high-power coherent polarization synthesized beam three; the coherent polarization synthesized beam one, the coherent polarization synthesized beam two, and the coherent polarization synthesized beam three are arranged in parallel; The beam combining mirror system comprises a total reflective mirror four (34), a total reflective mirror five (35), a total reflective mirror six (36), a total reflective mirror seven (37), a total reflective mirror eight (38), and a total reflective mirror nine (39), wherein the total reflective mirror four (34) and the total reflective mirror five (35), the total reflective mirror six (36) and the total reflective mirror seven (37), the total reflective mirror eight (38) and the total reflective mirror nine (39) are parallel to each other in pairs; the coherent polarized composite light beam one is reflected by the total reflective mirror four (34) and the total reflective mirror five (35) in sequence, the coherent polarized composite light beam two is reflected by the total reflective mirror six (36) and the total reflective mirror seven (37) in sequence, and the coherent polarized composite light beam three is reflected by the total reflective mirror eight (38) and the total reflective mirror nine (39) in sequence, thereby forming a triangular annular aperture laser beam.

2. A multi-channel laser synthetic aperture transmitting system according to claim 1, characterized in that: The Cassegrain beam expander system is composed of a primary mirror (41) and a secondary mirror (42) of a reflecting parabola. A triangular annular aperture light beam is incident obliquely on the total reflective mirror ten (30), reflected by the total reflective mirror ten (30), and then collimated and emitted to the secondary mirror (42) of the Cassegrain beam expander system, and then reflected from the secondary mirror (42) to the primary mirror (41), and finally reflected by the primary mirror (41) and emitted into the air.

3. A multi-channel laser synthetic aperture transmitting system according to claim 2, characterized in that: The fully reflective mirror 1 (31), fully reflective mirror 2 (32), fully reflective mirror 3 (33), fully reflective mirror 4 (34), fully reflective mirror 5 (35), fully reflective mirror 6 (36), fully reflective mirror 7 (37), fully reflective mirror 8 (38), fully reflective mirror 9 (39), fully reflective mirror 10 (30), and the primary mirror (41) and secondary mirror (42) of the Cassegrain beam expansion system are all coated with an optical reflective film, and the reflectivity is greater than 99%.

4. A multi-channel laser synthetic aperture transmitting system according to claim 2, characterized in that: The primary mirror (41) is a concave secondary aspheric reflector, and the secondary mirror (42) is a convex secondary aspheric reflector.

5. A multi-channel laser synthetic aperture transmitting system according to claim 2 or 4, characterized in that: The surface shape formula of the rotationally symmetric aspheric surface of the primary mirror (41) and the secondary mirror (42) is: Where c is the vertex curvature and k is the quadratic constant.

6. The multi-channel laser synthetic aperture transmitting system according to claim 2, characterized in that: The primary mirror (41) is simulated and designed using optical design software Zemax. The parameters of the primary mirror (41) are: vertex curvature radius R1 = 3000 mm; cone coefficient K = -1; effective aperture is Φ950 mm; material is microcrystalline glass; focal length is 1500 mm; coating is a dielectric high-reflection film with a reflectivity of >99%@1083 nm; surface quality is: RMS≤λ / 30, λ = 632.8 nm.

7. The multi-channel laser synthetic aperture transmitting system according to claim 2, characterized in that: The secondary mirror (42) is simulated and designed using optical design software Zemax. The parameters of the secondary mirror (42) are: secondary mirror vertex curvature radius R0 = 108 mm; cone coefficient K = -1; effective aperture is Φ34.2 mm; material is microcrystalline glass; focal length is 54 mm; coating is a dielectric high-reflection film with a reflectivity of >99%@1083 nm; surface quality is: RMS≤λ / 30, λ = 632.8 nm.

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