System and method for spectrum synthesis based on bar laser

Abstract

The invention belongs to the technical field of laser spectrum synthesis, and particularly discloses a system and a method for spectrum synthesis based on a bar laser. Comprising a bar laser array, a fast-axis collimating cylindrical mirror, a slow-axis collimating cylindrical mirror array, a volume Bragg grating wavelength locker, an optical module and a dispersion element which are sequentially arranged along a light path, the bar laser array is used for outputting a plurality of laser beams in parallel at equal intervals in the same direction, and the optical module is used for outputting the plurality of laser beams in parallel at equal intervals. The optical module is arranged on the volume Bragg grating wavelength locker and used for focusing the laser output by the volume Bragg grating wavelength locker, and the dispersion element is arranged at the focus of the optical module and used for receiving incident light and achieving multi-wavelength laser common-caliber output of high-power laser. According to the invention, spectrum synthesis of multiple paths of laser is realized based on the bar laser, and the device has the advantages of simple structure, easy control and flexible application, and has good application value in the aspect of synthesizing high-power laser output.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser spectrum synthesis, and more specifically, relates to a system and method for spectrum synthesis based on a bar laser. Background Art

[0002] In recent years, with the rapid development of laser technology and material technology, the power of laser systems has been increasingly required in the fields of industrial manufacturing and national defense security. The power of a single laser can no longer meet the needs of related applications. Spectral synthesis technology uses dispersion elements to achieve spatial overlap of multiple lasers with different wavelengths and synthesize them into a single-aperture high-energy laser, which has become an important way to increase the power of laser systems.

[0003] In the application of laser beam synthesis system engineering, the laser light source is a key component of the synthesis system, and the power of a single laser unit determines the peak power of the system output light. Increasing the number of laser units can directly increase the output laser power, but at the same time it will make the spectrum synthesis system more complicated. Therefore, the miniaturization and power improvement of single-channel laser units are important development directions for the light source part of the synthesis system. With the increasing development of semiconductor laser theory, materials, preparation processes and packaging technologies, the performance parameters of semiconductor lasers such as power, efficiency and life are constantly improving, and they have been used as high-power light sources in many fields such as industrial manufacturing and national defense security. Among them, bar lasers have the advantages of small size, light weight, high electro-optical conversion efficiency, flexible configuration, and long life under the trend of miniaturization of semiconductor lasers. In addition, assembling laser bars into stacked arrays is an important way to achieve high-power or ultra-high-power output, which can achieve kilowatt-level laser output. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a system and method for spectrum synthesis based on bar lasers, which composes bar laser units of different wavelengths into an array light source, locks the wavelength after collimation through a collimating lens group, and injects parallel light into the optical system, and then injects it into the dispersion element at a specific angle, and realizes the common aperture output of multi-wavelength lasers through the dispersion element. The present invention can realize the spectrum synthesis of multiple lasers based on bar lasers, and realize high-power laser output of 10,000 watts. It has the advantages of simple structure, easy control, and flexible application, and has good application value in synthesizing high-power laser output.

[0005] To achieve the above object, according to one aspect of the present invention, a system and method for spectrum synthesis based on bar lasers are proposed, comprising: a bar laser array 1, a fast axis collimating cylindrical mirror 2, a slow axis collimating mirror cylindrical array 3, a volume Bragg grating wavelength locker 4, an optical module 5 and a dispersion element 6, which are arranged in sequence along the optical path, wherein:

[0006] The bar laser array 1 is used to output multiple lasers in parallel at equal intervals in the same direction. The optical module 5 is used to focus the laser output by the volume Bragg grating wavelength locker 4. The dispersion element 6 is arranged at the focus of the optical module 5 to receive incident light and realize the common aperture output of multi-wavelength laser high-power laser.

[0007] As a further preferred embodiment, the bar laser array 1 comprises a plurality of bar lasers arranged in an array, and the laser wavelength band output by the bar lasers is in the range of 780nm to 860nm, or

[0008] The laser wavelength band output by the bar laser is in the range of 940nm to 980nm.

[0009] As a further preferred embodiment, the cylindrical center of the fast axis collimating cylindrical mirror 2 is aligned with the laser output center of the bar laser array 1 to ensure the fast axis direction collimation of each bar laser.

[0010] As a further preferred embodiment, the fast axis collimating cylindrical mirror 2 is a standard cylindrical mirror or a special-shaped cylindrical mirror.

[0011] As a further preferred embodiment, the cylindrical center of each slow axis collimator mirror array unit of the slow axis collimator mirror cylindrical array is aligned with the cylindrical center of the fast axis collimator mirror of the fast axis collimator cylindrical mirror and is aligned with the center of the laser output to ensure the slow axis direction collimation of each bar laser.

[0012] As a further preference, the slow axis collimating mirror cylindrical array 3 is a standard cylindrical mirror or a special-shaped cylindrical mirror.

[0013] As further preferred, the optical module includes a reflector, or

[0014] An optical system with a certain focal length that includes a combination of multiple reflective mirrors or transmissive mirrors.

[0015] As a further preferred embodiment, the mirror surface of the optical module 5 is any one of a spherical surface, an aspherical surface, and a free-form surface.

[0016] As a further preferred embodiment, a lens array 7 is also included in the volume Bragg grating wavelength locker 4, and each laser is coupled to the optical fiber 8 through the lens array 7, and the laser array is rearranged after passing through the optical fiber 8, and then incident on the optical module 5 in parallel.

[0017] According to another aspect of the present invention, a method for spectrum synthesis based on a bar laser is provided, comprising the following steps:

[0018] Step 1: Use a bar laser array 1 to output multiple lasers in parallel at equal intervals in the same direction;

[0019] Step 2: collimate the laser in the fast axis direction;

[0020] Step 3, after the laser is collimated in the fast axis direction, it is collimated in the slow axis direction;

[0021] Step 4, wavelength locking the parallel light beam after being collimated in the slow axis direction;

[0022] Step 5: After focusing the wavelength-locked laser, a dispersion element is used to receive the focused incident light to achieve a common aperture output of high-power lasers using multiple wavelength lasers.

[0023] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0024] 1. The present invention arranges multiple laser strips of different wavelengths into a beam array, and after the wavelength of the collimated parallel light is locked, each beam passing through the optical system is focused at a specific angle on the position of the dispersion element, thereby achieving multi-channel laser common aperture high-power laser output. The present invention has the advantages of simple structure and flexible application.

[0025] 2. The bar laser used in the present invention has high output power, simple structure, and is easy to control. The use of fiber-coupled output can also reduce the size of the system, which is beneficial to reducing the complexity of spectrum synthesis system integration and has the advantage of being lightweight and miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a spectrum synthesis system based on a bar laser involved in an embodiment of the present invention;

[0027] Figure 2 FIG. 4 is a schematic diagram of the arrangement of a bar laser array according to an embodiment of the present invention.

[0028] Figure 3 This is Example 2 of a spectrum synthesis method based on a bar laser of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Bar lasers can be single or multi-emitter, with single-emitter laser diodes providing up to 12W of optical output power. For higher power applications, multiple individual emitting areas (emitters) can be arranged side by side and integrated onto the same substrate as a laser diode array. When higher powers are required, multiple laser bars can be stacked horizontally or vertically. Stacking multiple bars allows for a highly modular approach to scale the power to the multi-kilowatt range. This modular approach provides the flexibility to scale the laser stack to the power level required for a given central wavelength, offering significant advantages and flexibility over traditional solid-state lasers. The size, weight, and power of laser diode stacks are greatly improved, with significantly higher peak power and brightness compared to traditional fiber and solid-state laser systems, making them suitable for portable and high-power applications. In addition, beam shaping optical modules can be used, mounted directly behind the bar array, for beam shaping and collimation to focus multiple output beams into a single high-power output beam. Optical modules can be used to collimate the laser beams on the fast and slow axes, shaping the beam into areas, lines, or points, depending on the application requirements. The main advantage of stacked laser bars is that, in addition to better performance than solid-state lasers, stacked laser bars also provide a simple and compact way to expand power. Therefore, bar arrays can be used in areas such as optical pumping of solid-state lasers, high directional energy, medical applications, and material processing. The high peak power of bar arrays can also be used for long-distance illumination that may require a propagation distance of several kilometers. In order to achieve sufficient target irradiance, multiple laser diode bars can be stacked into hundreds or even thousands of individual emitters.

[0031] Laser bar arrays are available in vertical or horizontal configurations and can operate in continuous wave and pulse modes. A horizontal bar array consists of multiple bars arranged side by side. This arrangement can achieve higher power output and better beam uniformity, and each bar output can be controlled and adjusted individually. Therefore, in view of the above characteristics of bar lasers, the present invention proposes a method for spectrum synthesis. Using bar lasers, high-power lasers in the 780nm to 860nm or 940nm to 980nm bands can be controlled and generated, and then collimated by a collimating lens group, and wavelength locked by a volume Bragg grating to accurately control the wavelength of each laser. After passing through the optical system, the spectrum is synthesized using a dispersion element, and finally a high-power laser output can be output.

[0032] like Figure 1As shown, a system for spectrum synthesis based on bar lasers provided by an embodiment of the present invention comprises: a bar laser array 1, a fast axis collimating cylindrical mirror 2, a slow axis collimating mirror cylindrical array 3, a volume Bragg grating wavelength locker 4, an optical module 5 and a dispersion element 6 arranged in sequence along an optical path, wherein the bar laser array 1 is used to output a plurality of lasers in parallel at equal intervals in the same direction, the optical module 5 is used to focus the laser output by the volume Bragg grating wavelength locker 4, and the dispersion element 6 is arranged at the focus of the optical module 5 to receive incident light and realize the common aperture output of multi-wavelength lasers with high power.

[0033] Preferably, the center of the cylinder of the fast-axis collimating cylindrical mirror 2 is aligned with the laser output center of the bar laser array 1 to ensure that the fast-axis direction of each bar laser is collimated.

[0034] Preferably, the fast axis collimating cylindrical mirror 2 is a standard cylindrical mirror or a special-shaped cylindrical mirror.

[0035] Preferably, the cylindrical center of each slow axis collimator mirror array unit of the slow axis collimator mirror cylindrical array 3 is aligned with the cylindrical center of the fast axis collimator mirror of the fast axis collimator cylindrical mirror 2 and is aligned with the center of the laser output to ensure the slow axis direction collimation of each bar laser.

[0036] Preferably, the slow-axis collimating mirror cylindrical array 3 is a standard cylindrical mirror or a special-shaped cylindrical mirror.

[0037] Preferably, the optical module 5 includes a reflector, or

[0038] An optical system with a certain focal length that includes a combination of multiple reflective mirrors or transmissive mirrors.

[0039] Preferably, the mirror surface of the optical module 5 is any one of a spherical surface, an aspherical surface, and a free-form surface.

[0040] In a preferred embodiment, the system further comprises a lens array 7 disposed in the volume Bragg grating wavelength locker 4, each laser is coupled to the optical fiber 8 through the lens array 7, and the laser array is rearranged after passing through the optical fiber 8, and then incident on the optical module 5 in parallel.

[0041] In addition, the workflow of the above system is as follows:

[0042] Step 1: Use a bar laser array 1 to output multiple lasers in parallel at equal intervals in the same direction;

[0043] Step 2: collimate the laser in the fast axis direction;

[0044] Step 3, after the laser is collimated in the fast axis direction, it is collimated in the slow axis direction;

[0045] Step 4, wavelength locking the parallel light beam after being collimated in the slow axis direction;

[0046] Step 5: After focusing the wavelength-locked laser, a dispersion element is used to receive the focused incident light to achieve a common aperture output of high-power lasers using multiple wavelength lasers.

[0047] Based on any of the above embodiments, the system further includes a control and monitoring module, which is connected to the bar laser array 1 and the Bragg grating wavelength locker 4 respectively, and is also used to detect the synthesized light output by the dispersion element 6. The control and monitoring module includes a wavelength sensor, a power sensor, and a PID controller, which is used to dynamically adjust the parameters of the Bragg grating wavelength locker 4 by using a PID control algorithm to achieve high-precision wavelength locking and quality control of the synthesized light by real-time monitoring of the output wavelength of the bar laser array 1 and the synthesized light output by the dispersion element 6, so as to achieve high-precision locking of the wavelength and quality control of the synthesized light.

[0048] Specifically, the basic formula of the PID controller is:

[0049]

[0050] Among them, u(t) is the control quantity, that is, the adjustment signal output by the controller. Kp is the proportional coefficient, which reflects the adjustment speed. e(t) is the current error, that is, the difference between the current wavelength and the target wavelength. Ki is the integral coefficient, which is used to eliminate the steady-state error. Ti is the integral time constant. Kd is the differential coefficient, which is used to predict the error trend and reduce overshoot. is the rate of change of error.

[0051] In practical applications, the PID algorithm needs to be discretized to adapt to digital control systems. The discretized PID formula can be expressed as:

[0052]

[0053] Among them, u(k) is the control quantity at the kth sampling time. e(k) is the error at the kth sampling time. T is the sampling period.

[0054] In this way, a high-efficiency and high-precision wavelength locking and beam quality control system can be constructed, which is suitable for laser applications requiring precise wavelength control and beam quality control.

[0055] Example 2

[0056] A spectrum synthesis method based on bar lasers: comprising a bar laser array 1, a fast axis collimating cylindrical mirror 2, a slow axis collimating cylindrical mirror array 3, a volume Bragg grating wavelength locker 4, an optical module 5, and a dispersion element 6. The steps for realizing high-power spectrum synthesis are as follows:

[0057] The first step is to arrange the laser array units in parallel and at equal intervals to ensure that the outgoing light beams are output in parallel and at equal intervals in the same direction.

[0058] Step 2: Place the fast axis collimating cylindrical mirror 2 at a certain distance behind the laser output position, align the cylindrical center of the fast axis collimating mirror with the laser output center to ensure that the fast axis direction of each laser bar is collimated.

[0059] Step 3: Place the slow axis collimator cylindrical array 3 at a certain distance behind the fast axis collimator cylindrical array 2, align the cylindrical center of each slow axis collimator array unit with the cylindrical center of the fast axis collimator to ensure that each laser bar is aligned in the slow axis direction.

[0060] Step 4: The collimated parallel light beam is incident on the volume Bragg grating wavelength locker 4 to lock the wavelength of each path.

[0061] Step 5: The collimated and locked parallel light is incident on the surface of the optical module 5, and the distance and tilt angle of the optical module 5 are adjusted to focus the parallel light.

[0062] Step 6: Place the dispersion element 6 at the focus of the optical module 5 to receive the incident light and realize the common aperture output of multi-wavelength lasers with high power.

[0063] The wavelength band of the bar laser array 1 can be but not limited to 780nm to 860nm or 940nm to 980nm, and has good wavelength stability and beam quality.

[0064] The fast axis collimating cylindrical mirror 2 may be, but is not limited to, a standard cylindrical mirror, anisotropic cylindrical mirror, or other cylindrical mirrors with fast axis collimating functions.

[0065] The slow axis collimating mirror cylindrical array 3 units may be, but are not limited to, cylindrical mirrors of various surface shapes having a slow axis collimating function, such as cylindrical standard mirrors and anisotropic cylindrical mirrors.

[0066] The optical module 5 may be, but is not limited to, a reflector, and may include a combination of multiple reflectors or transmission mirrors, and the mirror surface type includes, but is not limited to, spherical, aspherical, free-form surface, etc., and its function is to realize a collimated light beam incident in parallel and incident on the dispersion element 6 at a certain angle.

[0067] Example 3

[0068] See also Figure 1 , Figure 1 The present invention is an embodiment of a spectrum synthesis method based on a bar laser.

[0069] In this embodiment, 20 bar laser arrays 1 are arranged in a row in the x direction at equal intervals of 5 mm, each bar laser unit has an output power of 200 W, the wavelength of the bar laser at the center position is 808 nm, the center wavelengths of adjacent laser units differ by 2 nm, the light beam output direction is along the positive direction of the z-axis, the output light is collimated by the fast axis collimating cylindrical mirror 2 and the slow axis collimating cylindrical mirror array 3, and then multiple beams of parallel light are output, which are wavelength locked by the volume Bragg grating wavelength locker 4 and then incident in parallel to the optical module 5, the focal length of the optical module 5 is 2286.9 mm, the multi-channel lasers are focused on the dispersion element 6, the dispersion element has a line of 1000 line / mm, and after the dispersion element 6 acts, the main laser sub-beams are combined into a beam of light for output.

[0070] Example 4

[0071] See also Figure 2 , Figure 2 The present invention is an embodiment of a spectrum synthesis method based on a bar laser.

[0072] In this embodiment, 20 bar laser arrays 1 are arranged in a row at equal intervals in the x direction, each bar laser unit has an output power of 200 W, the bar laser wavelength at the center position is a central wavelength of 808 nm, the central wavelengths of adjacent laser units differ by 2 nm, the light beam output direction is along the positive direction of the z-axis, the output light is collimated by the fast axis collimating cylindrical mirror 2 and the slow axis collimating cylindrical mirror array 3, and then multiple beams of parallel light are output, which are wavelength locked by the volume Bragg grating wavelength locker 4, each laser is coupled to the optical fiber arrangement 8 through the lens array 7, and the laser array is rearranged after passing through the optical fiber, and the optical fibers are arranged at equal intervals of 2 mm, and then parallel incident on the optical module 5, the focal length of the optical module 5 is 914.8 mm, and the multiple lasers are focused on the dispersion element 6, the dispersion element has a line of 1000 line / mm, and after the dispersion element 6 acts, the main laser sub-beams are combined into a beam of light for output.

[0073] Example 5

[0074] Based on any combination of the above embodiments, in this embodiment, in order to achieve the consistency of the pulse laser peaks and troughs of the synthesized light beam during the beam combining process, a software algorithm optimization solution based on machine learning can be used. The details are as follows:

[0075] Collect the pulse waveform data of each bar laser unit, including light intensity Jd and time series;

[0076] Preprocessing of waveform data, including filtering and normalization, to reduce noise and improve data quality;

[0077] Extract key features of the waveform, such as pulse amplitude, center position, half-height width, etc.;

[0078] Calculate the slope of the waveform for adaptive selection of required waveform data;

[0079] Use machine learning algorithms, such as support vector machines (SVMs) or neural networks, to train waveform data to identify and predict the consistency of peaks and troughs, and use ridge regression algorithms to minimize the difference between target and output values ​​to optimize output weights;

[0080] Generally, the Gaussian function is used as the kernel function of the prediction model. Specifically, the Gaussian function model includes:

[0081]

[0082] Among them, A i , μ i 、F i represent the pulse amplitude, center position and half-height width of the i-th Gaussian component respectively.

[0083] Use historical data to train the model to improve the model's prediction accuracy;

[0084] According to the model prediction results, the parameters of the pulse laser control module are adjusted to optimize the waveform;

[0085] The rate equations of the chaotic system of chain-type mutually coupled semiconductor lasers are numerically solved using iterative algorithms, such as the fourth-order Runge-Kutta algorithm, to achieve real-time chaotic synchronization.

[0086] In this step, the fourth-order Runge-Kutta algorithm is used for iterative calculation, specifically:

[0087]

[0088] Where k1 = f(x n ,y n ), k4=f(x n +h,y n +hk3)

[0089] The pulsed laser waveform of the composite beam is monitored in real time, and the synchronization quality between the two laser outputs of the system is quantified using the cross-correlation function Cmn; the cross-correlation function Cmn includes:

[0090]

[0091] Where P(t)=|E(t)| 2 represents the output intensity of the laser, and m and n represent different laser units respectively.

[0092] The parameters of the Bragg grating wavelength locker are dynamically adjusted to achieve high-precision wavelength locking and quality control of the synthesized light.

[0093] Through the above scheme, the peak and trough consistency of the pulsed laser of the synthesized light beam can be effectively achieved, thereby improving the quality and application effect of laser synthesis.

[0094] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A system for spectrum synthesis based on bar lasers, characterized in that: include: A bar laser array (1), a fast axis collimating cylindrical mirror (2), a slow axis collimating cylindrical mirror array (3), a volume Bragg grating wavelength locker (4), an optical module (5) and a dispersion element (6) are sequentially arranged along an optical path, wherein: The bar laser array (1) is used to output a plurality of lasers in parallel at equal intervals in the same direction; the optical module (5) is used to focus the laser output by the volume Bragg grating wavelength locker (4); and the dispersion element (6) is arranged at the focus of the optical module (5) to receive incident light and realize the common aperture output of multi-wavelength lasers with high power.

2. A system for spectrum synthesis based on bar laser according to claim 1, characterized in that: The bar laser array (1) comprises a plurality of bar lasers arranged in an array, wherein the laser wavelength band output by the bar lasers is in the range of 780 nm to 860 nm, or The laser wavelength band output by the bar laser is in the range of 940nm to 980nm.

3. The system for spectrum synthesis based on bar laser according to claim 1, characterized in that: The center of the fast axis collimating cylindrical mirror of the fast axis collimating cylindrical mirror (2) is aligned with the laser output center of the bar laser array (1) to ensure the fast axis direction collimation of each bar laser.

4. The system for spectrum synthesis based on bar laser according to claim 1, characterized in that: The fast axis collimating cylindrical mirror (2) is a standard cylindrical mirror or a special-shaped cylindrical mirror.

5. The system for spectrum synthesis based on bar laser according to claim 1, characterized in that: The cylindrical center of each slow axis collimator mirror array unit of the slow axis collimator mirror cylindrical array (3) is aligned with the cylindrical center of the fast axis collimator mirror of the fast axis collimator cylindrical mirror (2) and is aligned with the center of the laser output, thereby ensuring the slow axis direction collimation of each bar laser.

6. The system for spectrum synthesis based on bar laser according to claim 5, characterized in that: The slow axis collimating mirror cylindrical array (3) is a standard cylindrical mirror or a special-shaped cylindrical mirror.

7. A system for spectrum synthesis based on bar lasers according to any one of claims 1 to 6, characterized in that: The optical module (5) comprises a reflector, or An optical system with a certain focal length that includes a combination of multiple reflective mirrors or transmissive mirrors.

8. The system for spectrum synthesis based on bar laser according to claim 7, characterized in that: The mirror surface of the optical module (5) is any one of a spherical surface, an aspherical surface, and a free-form surface.

9. The system for spectrum synthesis based on bar laser according to claim 7, characterized in that: It also includes a lens array (7) arranged on the volume Bragg grating wavelength locker (4), wherein each laser beam is coupled to the optical fiber (8) through the lens array (7), and the laser beam array is rearranged after passing through the optical fiber (8), and then incident on the optical module (5) in parallel.

10. A method for spectrum synthesis based on a bar laser, characterized in that: The following steps are involved: Step 1: using a bar laser array (1) to output multiple lasers in parallel at equal intervals in the same direction; Step 2: collimate the laser in the fast axis direction; Step 3, after the laser is collimated in the fast axis direction, it is collimated in the slow axis direction; Step 4, wavelength locking the parallel light beam after being collimated in the slow axis direction; Step 5: After focusing the wavelength-locked laser, a dispersion element is used to receive the focused incident light to achieve a common aperture output of high-power lasers using multiple wavelength lasers.

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