Laser amplification time pulse waveform compensation method and system based on Newton iteration method
By constructing a physical model of laser gain amplification through the Newton iteration method, the target input pulse is solved by reverse iteration, which solves the problem of pulse distortion during laser amplification, achieves high-precision pulse waveform compensation and uniform energy transmission, and improves processing quality and efficiency.
Patent Information
- Application Number
- CN202510757566.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-06
- Publication Date
- 2025-09-19
AI Technical Summary
During the laser amplification process, errors are introduced in the calculation of the functional relationship between the incident waveform and the output waveform, leading to pulse distortion. Existing pre-compensation technology relies on precise adjustment of system parameters, which can easily lead to poor compensation effects or generate new distortions.
The Newton iteration method is used to construct the physical model of laser gain amplification. The target input pulse is solved and optimized through reverse iteration. Combined with the Newton iteration process, the input pulse is continuously adjusted to offset the pulse distortion until the accuracy requirements are met.
It achieves high-precision pulse waveform compensation, reduces pulse distortion, ensures that the output pulse is consistent with the expected output, improves the processing edge quality and energy transmission uniformity, and enhances processing efficiency and consistency.
Smart Images
Figure CN120670707A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of optical technology, and in particular to a laser amplification time pulse waveform compensation method and system based on Newton iteration method. Background Art
[0002] The laser amplification process produces temporal pulse waveform distortion due to factors such as the gain medium. Therefore, the functional relationship between the incident waveform and the output waveform is calculated and derived. However, this theoretical calculation introduces errors, resulting in a deviation between the amplified output pulse and the theoretical output pulse. In order to ensure the reliability of the incident laser pulse, a method of correcting the pulse pre-compensation function by feedback of the incident laser pulse waveform is introduced.
[0003] At present, the effectiveness of pre-compensation technology is highly dependent on the precise adjustment of system parameters. If the parameters are set improperly, it may lead to poor compensation effect or even new distortion. This method improves the compensation accuracy by pre-processing some noise in the input and output waveform data and intercepting valid data. Summary of the Invention
[0004] The purpose of the present invention is to provide a laser amplification time pulse waveform compensation method and system based on Newton iteration method, aiming to offset the pulse distortion occurring during the laser pulse amplification process by pre-compensation, thereby obtaining good arbitrary desired output pulses.
[0005] To achieve the above object, the present invention provides a method and system for compensating laser amplification time pulse waveform based on Newton iteration method, comprising the following steps:
[0006] S1. Setting an expected output pulse according to the actual output pulse;
[0007] S2, constructing a laser gain amplification physical model and inputting the expected output pulse of S1 to obtain the input pulse;
[0008] S3, perform reverse iteration based on the input pulse obtained in S2 to solve the target input pulse and optimize it;
[0009] S4. Input the target input pulse obtained in S3 into the laser gain amplification physical model for verification with the expected output pulse.
[0010] Preferably, the specific process of S2 is as follows:
[0011] The calculation formula for the laser gain amplification physical model is as follows:
[0012]
[0013] Among them, I out (t) is I in(t) Time domain function of the output pulse after laser gain amplification, σ is the stimulated emission cross section, n0 is the initial inversion particle number density, L is the gain medium length, I in (t) is the time domain function of any input pulse, c is the speed of light in the medium, represents the time integration of the input pulse and is used in the denominator to describe the physical gain saturation effect.
[0014] Preferably, the specific process in S3 is as follows:
[0015] S31, the expected output pulse I target The time axis of (t) is discretized. In the time stepping method, starting from t(i), i = 1, the target input pulse I at each moment is calculated step by step. goal (t), so that I at this moment out (t) is equal to I target (t);
[0016] S32, through the target input pulse I goal Estimated input pulse estimate I guess , for each time point, the Newton iteration process is executed cyclically to obtain the target input pulse I goal .
[0017] Preferably, the Newton iteration process in S32 is as follows:
[0018] S321. Calculate the denominator of the laser gain amplification physical model:
[0019]
[0020] Among them, integral sum Indicates I goal The accumulated points up to time point i-1;
[0021] S322, calculate the current estimated output pulse I current The specific formula is as follows:
[0022]
[0023] S333. The specific formula for calculating residual is as follows:
[0024] residual=I current -I target ;
[0025] S334, calculate the denominator term denominator about I guess The derivative formula is as follows:
[0026]
[0027] S335, calculate the residual residual about I guess The derivative formula is as follows:
[0028]
[0029] S336. Finally, the Newton update formula is as follows:
[0030]
[0031] This method is continuously cycled, and when the residual is less than 10 -5 Stop the loop, at this time I guess This is the target input pulse I goal .
[0032] Preferably, the specific process of S4 is as follows:
[0033] The I obtained by reverse solution goal Input the laser gain amplification physical model to obtain the actual pulse output I stimulate , Verify I stimulate The obtained waveform is consistent with the expected output pulse I target The consistency of the waveform; if the deviation exceeds the allowable range, the feedback correction model parameters change the integration step size, and the iterative process is repeated until the accuracy requirements are met.
[0034] To achieve the above objectives, the present invention also provides a laser amplification time pulse waveform compensation system based on the Newton iteration method, including a seed source, a MOPA amplification system and a computer control system. The seed source integrates a single longitudinal mode fiber laser, an arbitrary waveform generator (AWG) and an LD amplifier; the MOPA amplification system adopts a side-pumped Nd:YAG rod crystal amplifier, and the arbitrary waveform generator (AWG) adopts the model AWG70001A.
[0035] Therefore, the present invention adopts a laser amplification time pulse waveform compensation method and system based on the Newton iteration method, which has the following beneficial effects compared with the prior art:
[0036] The error between the compensated pulse waveform and the target waveform is very small, the algorithm is simple, and the compensation efficiency is high. It solves the pulse distortion problem caused by gain saturation in traditional laser amplification, can accurately control the output to a standardized waveform, improve waveform distortion, achieve more uniform energy transmission, improve processing edge quality, reduce heat-affected zone, and improve processing efficiency and consistency.
[0037] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0038] Figure 1 This is a step diagram of a laser amplification time pulse waveform compensation method based on Newton iteration method of the present invention;
[0039] Figure 2 This is an algorithm flow chart of a laser amplification time pulse waveform compensation method based on Newton iteration method of the present invention;
[0040] Figure 3 This is a structural diagram of a laser amplification time pulse waveform compensation system based on Newton iteration method of the present invention;
[0041] Figure 4 This is a square wave waveform diagram of a laser amplification time pulse waveform compensation system based on Newton iteration method of the present invention;
[0042] Figure 5 It is a Gaussian waveform diagram of a laser amplification time pulse waveform compensation system based on Newton iteration method of the present invention. DETAILED DESCRIPTION
[0043] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.
[0044] Example
[0045] like Figure 1-Figure 5 As shown, a laser amplification time pulse waveform compensation method and system based on Newton iteration method of the present invention includes the following steps:
[0046] S1. Setting an expected output pulse according to the actual output pulse;
[0047] S2, constructing a laser gain amplification physical model and inputting the expected output pulse of S1 to obtain the input pulse;
[0048] The calculation formula for the laser gain amplification physical model is as follows:
[0049]
[0050] Among them, I out (t) is I in (t) Time domain function of the output pulse after laser gain amplification, σ is the stimulated emission cross section, n0 is the initial inversion particle number density, L is the gain medium length, I in(t) is the time domain function of any input pulse, c is the speed of light in the medium, Represents the time accumulation of the input pulse and is used in the denominator to describe the physical gain saturation effect;
[0051] S3, perform reverse iteration based on the input pulse obtained in S2 to solve the target input pulse and optimize it;
[0052] S31, the expected output pulse I target The time axis of (t) is discretized. In the time stepping method, starting from t(i), i = 1, the target input pulse I at each moment is calculated step by step. goal (t), so that I at this moment out (t) is equal to I target (t);
[0053] S32, through the target input pulse I goal Estimated input pulse estimate I guess , for each time point t, the Newton iteration process is executed cyclically to obtain the target input pulse I goal ;
[0054] S321. Calculate the denominator of the laser gain amplification physical model:
[0055]
[0056] Among them, integral sum Indicates I goal The accumulated points up to time point i-1;
[0057] S322, calculate the current estimated output pulse I current The specific formula is as follows:
[0058]
[0059] S333. The specific formula for calculating residual is as follows:
[0060] residual=I current -I target ;
[0061] S334, calculate the denominator term denominator about I guess The derivative formula is as follows:
[0062]
[0063] S335, calculate the residual residual about I guess The derivative formula is as follows:
[0064]
[0065] S336. Finally, the Newton update formula is as follows:
[0066]
[0067] This method is continuously cycled, and when the residual is less than 10 -5 Stop the loop, at this time I guess This is the target input pulse I goal ;
[0068] S4, inputting the target input pulse obtained in S3 into the laser gain amplification physical model to verify the expected output pulse;
[0069] The I obtained by reverse solution goal Input the laser gain amplification physical model to obtain the actual pulse output I stimulate , verify that the waveform obtained is consistent with the expected output pulse I target The consistency of the waveform; if the deviation exceeds the allowable range, the feedback correction model parameters change the integration step size, and the iterative process is repeated until the accuracy requirements are met.
[0070] To achieve the above objectives, the present invention also provides a laser amplification time pulse waveform compensation system based on the Newton iteration method, including a seed source, a MOPA amplification system and a computer control system. The seed source integrates a single longitudinal mode fiber laser, an arbitrary waveform generator (AWG) and an LD amplifier; the MOPA amplification system adopts a side-pumped Nd:YAG rod crystal amplifier, and the arbitrary waveform generator (AWG) adopts the model AWG70001A.
[0071] The specific implementation process is as follows:
[0072] 1. The initial requirements are imported into the AWG through the computer control system. The seed light source output is used as the input pulse I under the action of the AWG and the amplitude modulator. in , simulate MOPA amplification and obtain the output pulse I out ;
[0073] 2. According to the output pulse I out The pulse width and shape of the desired output pulse I target ;
[0074] 3. Use the expected output pulse I target The initial pulse I after compensation is obtained by reverse iteration of the compensation algorithm. goal ; The compensation algorithm process is as follows Figure 2As shown, after the start, the physical parameters and convergence conditions are initialized, and the time step cycle is entered. The time points are traversed and the desired output time axis is discretized into a step size Δt. In the time step method, starting from t = 0, the target input pulse I at each moment is calculated step by step. goal (t), so that I at this moment out (t) is equal to I target (t).
[0075] Through the target input pulse I goal Estimated input pulse estimate I guess , for the first time point t(i), i=1, calculate the current estimated output pulse I current , the next step is to calculate the residual and determine whether the residual is less than the preset residual. If not, calculate the denominator of I guess The derivative of the residual, and the residual to I guess The derivative of , then Newton update I guess If satisfied, then enter the next time point; through this method, continue to cycle until the time point cycle is completed, and output the I at this time gues s is the target input pulse I goal (t).
[0076] 4. Use the compensated initial pulse I goal After analog amplification, the compensated amplified output pulse I target .
[0077] Therefore, the present invention adopts the above-mentioned laser amplification time pulse waveform compensation method and system based on Newton iteration method, aiming to offset the pulse distortion occurring during the laser pulse amplification process through pre-compensation, thereby obtaining good arbitrary desired output pulses.
[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A laser amplification time pulse waveform compensation method based on Newton iteration method, characterized by: The following steps are involved: S1. Setting an expected output pulse according to the actual output pulse; S2, constructing a laser gain amplification physical model and inputting the expected output pulse of S1 to obtain the input pulse; S3, perform reverse iteration based on the input pulse obtained in S2 to solve the target input pulse and optimize it; S4. Input the target input pulse obtained in S3 into the laser gain amplification physical model for verification with the expected output pulse.
2. The laser amplification time pulse waveform compensation method based on Newton iteration method according to claim 1, characterized in that: The specific process of S2 is as follows: The calculation formula for the laser gain amplification physical model is as follows: Among them, i out (t) is I in (t) Time domain function of the output pulse after laser gain amplification, σ is the stimulated emission cross section, n0 is the initial inversion particle number density, L is the gain medium length, I in (t) is the time domain function of any input pulse, c is the speed of light in the medium, represents the time integration of the input pulse and is used in the denominator to describe the physical gain saturation effect.
3. The laser amplification time pulse waveform compensation method based on Newton iteration method according to claim 2, characterized in that: The specific process in S3 is as follows: S31, the expected output pulse I target The time axis of (t) is discretized. In the time stepping method, starting from t(i), i = 1, the target input pulse I at each moment is calculated step by step. goal (t), so that I at this moment out (t) is equal to I target (t); S32, through the target input pulse I goal Estimated input pulse estimate I guess , for each time point t, the Newton iteration process is executed cyclically to obtain the target input pulse I goal .
4. The laser amplification time pulse waveform compensation method based on Newton iteration method according to claim 3, characterized in that: The Newton iteration process in S32 is as follows: S321. Calculate the denominator of the laser gain amplification physical model: Among them, integral sum Indicates I goal The accumulated points up to time point i-1; S322, calculate the current estimated output pulse I current The specific formula is as follows: S333. The specific formula for calculating residual is as follows: residual=I current -I target ; S334, calculate the denominator term denominator about I guess The derivative formula is as follows: S335, calculate the residual residual about I guess The derivative formula is as follows: S336. Finally, the Newton update formula is as follows: This method is repeated continuously, and when the residual is less than 10 -5 Stop the loop, at this time I guess This is the target input pulse I goal .
5. The laser amplification time pulse waveform compensation method based on Newton iteration method according to claim 4, characterized in that: The specific process of S4 is as follows: The I obtained by reverse solution goal Input the laser gain amplification physical model to obtain the actual pulse output I stimulate Get the actual pulse output Get the actual pulse output and verify I stimulate The obtained waveform is consistent with the expected output pulse I target Waveform consistency; If the deviation exceeds the allowable range, the feedback correction model parameters are changed to change the integration step size, and the iterative process is repeated until the accuracy requirements are met.
6. A laser amplification time pulse waveform compensation system based on Newton iteration method, characterized by: A laser amplification time pulse waveform compensation method based on the Newton iteration method as described in any one of claims 1 to 5 is applied, the system comprising a seed source, a MOPA amplification system and a computer control system, the seed source integrating a single longitudinal mode fiber laser, an arbitrary waveform generator (AWG) and an LD amplifier; the MOPA amplification system adopts a side-pumped Nd:YAG rod crystal amplifier, and the arbitrary waveform generator (AWG) adopts the model AWG70001A.