Laser frequency stabilization device and method based on etalon frequency measurement technology

Abstract

The invention provides a laser frequency stabilization device and method based on an etalon frequency measurement technology, and the device comprises a laser light source emission modulation assembly, a frequency detection assembly and a main control device, and the influence of associated amplitude modulation is eliminated by introducing a first photoelectric detector to measure a reference signal. In the frequency stabilization process, a coarse adjustment method for large drift of the laser frequency and a fine adjustment method for small drift of the laser frequency are adopted to realize efficient frequency locking of the laser, that is, when the drift distance of the laser frequency exceeds the adjustment range of the acoustic optical modulator, the frequency of the laser is adjusted. The center frequency of the laser is coarsely adjusted by changing the voltage and current of the laser, after it is ensured that the center frequency drift distance of the laser falls within the adjustable range of the acousto-optic modulator, the phase offset of an etalon interference signal and a reference light signal is solved by using a simulation model in combination with a similarity demodulation algorithm, and the phase offset of the etalon interference signal and the reference light signal is calculated. And adjusting a radio frequency signal source for driving the acousto-optic modulator according to the obtained laser frequency drift distance so as to realize fine tuning of the laser frequency.

Description

Technical Field

[0001] The present invention relates to the field of laser application technology, and in particular to a laser frequency stabilization device and method based on etalon frequency measurement technology. Background Art

[0002] Narrow linewidth frequency-stabilized lasers are widely used in engineering and scientific research due to their good monochromaticity, coherence and excellent collimation. For example, in physics, the wavelength and frequency of the frequency-stabilized laser can be measured accurately to improve the measurement accuracy of the speed of light. In spectroscopy, frequency-stabilized lasers can provide high-resolution and high-precision spectral data in spectral analysis, which is often used to study the structure and properties of matter. In communications, when the laser is used as a light source in an optical fiber communication system, the frequency-stabilized laser can improve the stability and transmission distance of the signal and reduce noise and interference. In atomic clocks and time frequency standards, frequency-stabilized lasers are used in atomic clocks to accurately lock the atomic transition frequency, thereby improving the accuracy of time and frequency standards. In manufacturing and processing, in laser processing and micro-processing technology, frequency-stabilized lasers are used for precision cutting, welding or other processing to provide high-precision processing quality. In these high-precision application fields, the drift of the laser frequency output by the laser will have an adverse effect on the results. The frequency drift of the laser is mainly caused by temperature changes, mechanical vibrations, and power changes in the working environment of the laser. For high-precision measurement and actual engineering application scenarios, lasers with high frequency stability are required.

[0003] The main frequency stabilization methods disclosed in the prior art mainly include differential frequency locking technology and phase-locked frequency stabilization technology, wherein the phase-locked frequency stabilization technology is a technology that compares the output frequency of the laser with a stable reference signal and locks its frequency through a feedback control loop, which can achieve highly stable and accurate laser frequency output. For example, PDH frequency locking technology is one of the representative methods, which can meet the frequency stabilization requirements of lasers of different wavelengths, but the structure of its electrical modulation system is relatively complex, the adjustment process is complicated and cumbersome, and the cost is high. Therefore, a laser frequency stabilization method and device with a simple and reliable structure and moderate cost is needed. Summary of the invention

[0004] Based on the problems mentioned in the background technology, the present invention proposes a laser frequency stabilization device and method based on standard tool frequency measurement technology, which has a simple and reliable structure, moderate cost, and a simple and efficient adjustment process.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: in the first aspect, the present invention proposes a laser frequency stabilization device based on the etalon frequency measurement technology, which includes: a laser light source emission modulation component, which includes a laser, a signal generator for adjusting the emission frequency of the laser, an acousto-optic modulator arranged in the emission direction of the laser, and a radio frequency signal source connected to the signal of the acousto-optic modulator; a frequency detection component, which includes a first spectrometer arranged on the light-emitting side of the acousto-optic modulator, an etalon arranged on one of the light-emitting sides of the first spectrometer, a first photodetector arranged on the other light-emitting side of the first spectrometer, and a second photodetector arranged on the light-emitting side of the etalon; a main control device, the signal input end of the main control device is connected to the first photodetector and the second photodetector signal, and the signal output end of the main control device is connected to the radio frequency signal source and the signal generator signal.

[0006] Furthermore, the laser light source emission modulation component also includes an optical isolator arranged between the laser and the acousto-optic modulator.

[0007] Furthermore, a second beam splitter is provided on the light output side of the acousto-optic modulator, and the first beam splitter is provided on one of the light output sides of the second beam splitter.

[0008] Furthermore, the frequency detection component also includes a constant temperature module, and the standard tool is arranged in the constant temperature module.

[0009] In a second aspect, the present invention further discloses a frequency stabilization method of a laser frequency stabilization device, which comprises:

[0010] Step 1, collecting spectral data passing through the etalon;

[0011] Step 2, adjusting the laser operating current and voltage to ensure that the difference between the laser center frequency and the selected etalon interference peak frequency is within the frequency adjustment range of the acousto-optic modulator;

[0012] Step 3, based on the principle of achieving the highest similarity between the laser center frequency and the interference peak frequency of the standard, the driving signal of the acousto-optic modulator outputted by the RF signal source is changed according to the required laser frequency drift amount demodulated.

[0013] Furthermore, step 2 includes: using the simulation model to generate spectrum data of the laser of the laser under the current parameter conditions, and by comparing the ratio of the valley heights of the selected etalon interference peak frequency, it is determined whether the difference between the current laser center frequency and the selected etalon interference peak frequency is greater than the frequency adjustment range of the acousto-optic modulator; if so, adjusting the laser operating current and voltage parameters so that the difference between the laser center frequency and the selected etalon interference peak frequency is within the frequency adjustment range of the acousto-optic modulator.

[0014] Furthermore, the measured etalon interference signal with the associated amplitude modulation eliminated is obtained by dividing the etalon original signal by the reference light signal.

[0015] Furthermore, the collected etalon interference signal can be expressed as: in In the above formula, I i is the input light intensity, F is the fineness of the etalon, R is the reflectivity of the etalon reflection plane, δ is the phase difference between adjacent light beams during interference, θ is the incident angle of the light beam, λ is the laser wavelength, n is the refractive index of the laser transmission medium, and h is the distance between the two reflection surfaces of the etalon.

[0016] Furthermore, in step 3, the required laser frequency drift is demodulated by continuously adjusting the center frequency parameters of the laser to obtain the laser center frequency with the highest similarity to the interference peak frequency of the etalon. When the value of the laser center frequency in the simulation model is changed, the laser center frequency value is adjusted based on the initial value of the laser center frequency in the simulation model. The minimum change of the frequency parameter is where f FSR is the free spectrum range frequency of the etalon, N FSR is the number of sampling points within the free spectrum of the etalon.

[0017] Compared with the prior art, the present invention is based on an etalon as a frequency locking reference for the laser, and eliminates the influence of the associated amplitude modulation by introducing a reference signal measured by a first photodetector. In the process of frequency stabilization, a coarse adjustment method for when the laser frequency has a large drift and a fine adjustment method for when the laser drift frequency is small are adopted to achieve efficient frequency locking of the laser, that is, when the laser frequency drift exceeds the adjustment range of the acousto-optic modulator, the center frequency of the laser is coarsely adjusted by changing the voltage and current of the laser to ensure that the center frequency drift of the laser falls within the adjustable range of the acousto-optic modulator, and then a simulation model is used in combination with a similarity demodulation algorithm to obtain the phase offset between the etalon interference signal and the reference light signal, and the radio frequency signal source driving the acousto-optic modulator is adjusted according to the obtained laser frequency drift to achieve fine tuning of the laser frequency, which well solves the problem of complex control system when the existing tunable laser adopts phase-locked frequency stabilization, and has a simple optical path structure and strong anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic block diagram of the overall structure in an embodiment of the present invention.

[0019] Figure 2 This is a flow chart of the laser frequency stabilization algorithm in the present invention.

[0020] Figure 3 It is a schematic diagram of the laser frequency stabilization process in the present invention.

[0021] Figure 4 It is the broadband light source transmission spectrum of the etalon in the present invention.

[0022] Figure 5 This is the spectrum of the local frequency-sweeping transmission light of the etalon in the present invention superimposed on the laser output.

[0023] Figure 6 It is the measured data and simulation model signal diagram of the standard tool in the present invention.

[0024] Figure 7 It is a schematic diagram of eliminating the associated amplitude modulation of the etalon interference signal in the present invention.

[0025] Figure 8 It is a schematic diagram of the interference signal of the etalon at the target stabilization frequency in the present invention.

[0026] The main markings in the figure are: 1. Laser light source emission modulation component; 2. Laser; 3. Optical isolator; 4. Acousto-optic modulator; 5. Signal generator; 6. RF signal source; 7. Second spectrometer; 8. Frequency detection component; 9. First optical coupler; 10. Standard tool; 11. Constant temperature module; 12. First photodetector; 13. Second photodetector; 14. Main control device; 15. Industrial computer; 16. Frequency-stabilized laser output terminal. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention. Figure 1 As shown, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, the present invention provides a laser frequency stabilization device based on standard tool frequency measurement technology, which includes three major components, namely a laser light source emission modulation component, a frequency detection component and a main control device.

[0030] Among them, the laser light source emission modulation component mainly includes a laser, a signal generator, an acousto-optic modulator and a radio frequency signal source. The laser is a single-mode laser or an external cavity laser with relatively small frequency fluctuation, which can effectively avoid frequency unlocking. The laser outputs a corresponding frequency-sweeping laser under the triangular wave voltage modulation of the signal generator. The laser enters the acousto-optic modulator after passing through the optical isolator and is divided into two laser beams by the second beam splitter, one of which is the laser output after frequency stabilization, and the other enters the frequency detection component part. Both laser beams are modulated by the acousto-optic modulator. The laser frequency passing through the acousto-optic modulator produces a corresponding frequency shift under the drive of the radio frequency signal source; wherein, the laser center frequency can be changed by adjusting the working current of the laser, so that it is offset to the vicinity of one of the transmission peaks of the standard tool, forming an error signal containing the laser frequency drift information, and the coarse adjustment of the laser output frequency is achieved by adjusting the working current of the laser. The acousto-optic modulator achieves fine adjustment of the laser frequency in a small range under the drive of the radio frequency signal source. An optical isolator is also provided between the laser and the AOM to prevent a small amount of reflected light from the etalon from entering the laser and thereby damaging the working life and working stability of the laser.

[0031] Preferably, the optical splitter can use an optical coupler to ensure that the laser is normally output to the frequency detection part and outputs the laser after frequency stabilization.

[0032] The frequency detection component is composed of an etalon that matches the center frequency of the laser, a constant temperature module, and two photodetectors. The etalon is an interference device with two parallel reflective end faces. When the light beam enters the etalon, multi-beam interference occurs. The nature of the interference signal is mainly determined by the distance between the two reflective end faces of the resonant cavity and the medium. The matching etalon is customized in combination with the center frequency of the laser and the adjustable frequency range. The constant temperature module is composed of a metal constant temperature bath, a semiconductor refrigeration sheet, a temperature sensor, and a temperature feedback control circuit; the etalon is placed in the constant temperature module to isolate the influence of the external temperature on the etalon, and its operating temperature is monitored in real time by an industrial computer. The photodiode is used to detect the two optical signals before and after entering the etalon, and convert the optical signals into electrical signals. The laser entering the frequency detection component is divided into two beams by the first splitter with a splitting ratio of 10%:90%. The laser beam with 10% optical power is the reference laser, which directly enters the first photodetector and is converted into an electrical signal; the laser beam with 90% optical power enters the standard placed in the constant temperature module (TEC constant temperature module) to perform multi-beam interference and measure the difference between the laser center frequency and the interference peak frequency value selected by the standard. The standard interference signal enters the second photodetector and enters the main control device at the same time as the reference optical signal.

[0033] The main control device is an industrial computer equipped with a high-speed acquisition card. The signal input end of the main control device is connected to the first photodetector and the second photodetector signal, and the signal output end of the main control device is connected to the RF signal source and the signal generator signal. The reference signal and the error signal of the laser frequency drift measured by the standard tool are collected by the high-speed acquisition card. The use of the high-speed acquisition card can improve the laser frequency resolution within the free spectrum range of the standard tool. The reference light signal and the standard tool interference signal are collected and processed by the industrial computer. After processing the error signal, the driving signal of the laser and the RF driving signal of the acousto-optic modulator are controlled through serial communication.

[0034] Furthermore, the present invention also proposes a specific frequency stabilization method based on the above laser frequency stabilization device. Figure 2 , 3 As shown, the frequency stabilization process is mainly carried out by combining the simulation model.

[0035] The method mainly includes:

[0036] Step 1, collecting spectral data passing through the etalon;

[0037] Step 2, adjusting the laser operating current and voltage to ensure that the difference between the laser center frequency and the selected etalon interference peak frequency is within the frequency adjustment range of the acousto-optic modulator;

[0038] Step 3, based on the principle of achieving the highest similarity between the laser center frequency and the interference peak frequency of the standard, the driving signal of the acousto-optic modulator outputted by the RF signal source is changed according to the required laser frequency drift amount demodulated.

[0039] First, in the initial stage, the system power is turned on. After the internally modulated laser enters the acousto-optic modulator through the optical isolator, one of the laser beams after two splittings enters the etalon for interference. The working current, voltage and working temperature of the laser are empirically adjusted to make the frequency of the interference signal of the etalon twice the modulation frequency of the laser, and converted into an electrical signal by the second photodetector; the other beam directly enters the first photodetector and is converted into an electrical signal, and enters the high-speed acquisition card in the industrial computer as a reference signal. The laser entering the etalon will interfere after multiple reflections in the resonant cavity of the etalon. Only lasers with specific wavelengths that meet the resonance conditions can be transmitted out of the etalon after multi-beam interference, forming a sharp interference peak; the etalon is placed in the TEC constant temperature module to prevent the resonant cavity length of the etalon from changing with temperature, thereby being affected by the crosstalk of the ambient temperature. The interference signal and reference light signal of the etalon are respectively connected to two photodetectors and converted into electrical signals, and then enter the high-speed acquisition card together.

[0040] Then, during the operation of the laser frequency stabilization device, data is collected in real time. The collected data includes spectral data passing through the standard tool and the laser signal detected by the photodetector. The simulation model compares the laser spectrum under the initial parameters (current, voltage and center frequency, etc.) with the spectral data passing through the standard tool. By comparing the ratio of the height between the valleys of the interference signal, it is known whether the difference between the currently measured laser center frequency and the selected standard tool interference peak frequency is greater than the frequency adjustment range of the acousto-optic modulator. If greater, the laser operating current and voltage are adjusted so that the difference between the laser center frequency and the selected standard tool interference peak frequency is within the frequency adjustment range of the acousto-optic modulator. For example, the interference signal after passing through the etalon is collected by a photoelectric detector. The etalon is the core component used to detect the deviation of the laser frequency. After the laser beam passes through the etalon, a series of interference peaks and valleys are generated. These peaks and valleys reflect the difference between the laser frequency and the resonance frequency of the etalon. After obtaining the interference signal, a specific interference peak is selected, and the height ratio between its valleys is calculated. This ratio reflects the degree to which the laser frequency deviates from the resonance frequency of the etalon. The position of the interference peak in the interference signal is determined, and the height (light intensity difference) of two adjacent valleys is measured. The normalized ratio is obtained by dividing the height difference between the valleys of a certain interference peak by the reference light intensity value of the interference peak. The main control device analyzes the valley height ratio of the selected interference peak frequency and infers the frequency difference between the current laser center frequency and the interference peak frequency of the etalon. Here, the key is to compare the valley height ratio with the frequency adjustment range of the acousto-optic modulator. Based on the ratio of the valley heights of the interference signal, the deviation of the laser frequency relative to the resonance frequency of the etalon can be calculated. The acousto-optic modulator has a specific frequency adjustment range (such as MHz or GHz). The main control device determines whether the laser frequency deviation exceeds the adjustable range by comparing the ratio with the set threshold (based on the frequency adjustment range of the acousto-optic modulator). If it is calculated that the difference between the laser center frequency and the etalon interference peak frequency is greater than the frequency adjustment range of the acousto-optic modulator, the main control device will issue an adjustment instruction to the RF signal source and the signal generator to adjust the frequency output of the laser until the difference falls within the adjustable range of the acousto-optic modulator. Through multiple feedback and adjustments, the laser frequency is finally locked within the required frequency range to ensure frequency stability.

[0041] Next, when the difference between the laser center frequency and the selected standard interference peak frequency is within the frequency adjustment range of the acousto-optic modulator, the simulation model generates a simulation error signal whose laser center frequency is directly opposite to the selected standard interference peak frequency. The frequency of the signal should be twice the frequency of the reference light signal, and its interference peaks and interference valleys are of equal height. By changing the value of the laser center frequency (the initial center frequency) in the simulation model, a series of simulation signals are generated, and the similarity of all simulation signals and the measured standard interference signal is calculated by the similarity algorithm. The laser center frequency parameter value of the simulation signal with the highest similarity is taken as the target center frequency of the laser. The purpose of this step is to make the simulation signal consistent with the measured signal by fine-tuning the relevant parameters; at this time, the target center frequency is the final required laser center frequency, and the laser frequency drift is demodulated according to the target center frequency. Then, the driving signal of the acousto-optic modulator outputted by the RF signal source is changed according to the demodulated laser frequency drift, so as to achieve the highest similarity between the laser center frequency and the standard interference peak frequency, so as to achieve fine adjustment of the laser center frequency.

[0042] It should be noted that due to the influence of the amplitude modulation associated with the modulation in the laser, it is necessary to divide the original signal of the etalon by the reference light signal to obtain the above-mentioned measured etalon interference signal that eliminates the associated amplitude modulation. The collected etalon interference signal can be expressed as: in In the above formula, I i is the input light intensity, F is the fineness of the etalon, R is the reflectivity of the etalon reflection plane, δ is the phase difference between adjacent light beams during interference, θ is the incident angle of the light beam, λ is the laser wavelength, n is the refractive index of the laser transmission medium, and h is the distance between the two reflection surfaces of the etalon.

[0043] When changing the value of the laser center frequency in the simulation model, the laser center frequency value is adjusted based on the initial value of the laser center frequency in the simulation model. The minimum change in the frequency parameter is where f FSR is the free spectrum range frequency of the etalon, N FSR is the number of sampling points within the free spectrum of the etalon.

[0044] The following is an example to illustrate:

[0045] The etalon with a free spectral range (FSR) of 50 GHz was selected, and the center frequency of the laser was 193.405 THz (1550.0748 nm). Figure 4 As shown. Figure 5As shown, the local swept transmission light of the etalon and the laser output of the narrow linewidth laser are simultaneously connected to the spectrometer to obtain the spectrum of the local swept transmission light of the etalon superimposed on the laser output. In practice, when the center frequency of the laser is not aligned with the frequency of the selected etalon interference peak, the heights between the etalon interference signal valleys will be inconsistent, and the phase of the interference signal will shift left and right with the drift of the laser center frequency. The heights between the etalon interference signal valleys shown in the figure are consistent, indicating that the center frequency of the laser is aligned with the frequency of the selected etalon interference peak. At the same time, the center frequency of the laser shown in the figure below is almost at the etalon interference peak frequency.

[0046] Then, with the target frequency of stabilization set to 193.405THz (1550.0748nm), after collecting data, we can see Figure 6 As shown, there is a small gap between the current measured laser center frequency and the selected standard tool interference peak frequency (the ratio of the valley heights of the selected standard tool interference peak frequency), so it is known that the difference between the current measured laser center frequency and the selected standard tool interference peak frequency is less than the frequency adjustment range of the acousto-optic modulator. Within the frequency adjustment range of the acousto-optic modulator, there is no need to change the working current and voltage. It should be noted that the model here is obtained by using the reference light signal to suppress the influence of the amplitude modulation associated with the modulation in the laser on the standard tool interference signal. Figure 7 As shown, the curve with a higher peak value is the collected original interference signal of the etalon, the broken line is the collected reference light signal, and the curve with a lower peak value is the interference signal of the etalon with the associated amplitude modulation eliminated, which is obtained by dividing the original signal of the etalon by the reference light signal. It should be noted that the curves in the figure are normalized for the convenience of display, and the horizontal axis of the figure is the number of sampling points. It can be seen from the figure that if the influence of the associated amplitude modulation is not eliminated, when the laser center frequency is not at the interference peak frequency value selected by the etalon, the height of the valley of the interference signal will also be affected, which will eventually affect the demodulation result. Therefore, after eliminating the associated amplitude modulation, Figure 8 Schematic diagram of the interference signal shown.

[0047] According to the obtained simulation model, the initial laser center frequency parameters in the simulation model are set to 193.405THz (1550.0748nm), the sweep range is 350MHz, the long-term stability of the laser is good, and the frequency drift is generally within the adjustment range of the acousto-optic modulator. The laser center frequency parameters are fine-tuned on the basis of 193.405THz. The minimum change of the frequency parameters in the simulation model is A series of standard tool simulation interference signals are obtained, and the similarity between the subsequently measured standard tool interference and this series of signals is sought. The frequency parameters of the group of simulation signals with the greatest similarity are taken, which is used as the target center frequency of the laser output by the laser at this time. Then, the driving signal of the acousto-optic modulator output by the RF signal source is changed according to the laser frequency drift demodulated by the industrial computer, so as to achieve the highest similarity between the laser center frequency and the standard tool interference peak frequency, so as to achieve fine adjustment of the laser center frequency.

[0048] Compared with the prior art, the present invention is based on an etalon as a frequency locking reference for the laser, and eliminates the influence of the associated amplitude modulation by introducing a reference signal measured by a first photodetector. In the process of frequency stabilization, a coarse adjustment method for when the laser frequency has a large drift and a fine adjustment method for when the laser drift frequency is small are adopted to achieve efficient frequency locking of the laser, that is, when the laser frequency drift exceeds the adjustment range of the acousto-optic modulator, the center frequency of the laser is coarsely adjusted by changing the voltage and current of the laser to ensure that the center frequency drift of the laser falls within the adjustable range of the acousto-optic modulator, and then a simulation model is used in combination with a similarity demodulation algorithm to obtain the phase offset between the etalon interference signal and the reference light signal, and the radio frequency signal source driving the acousto-optic modulator is adjusted according to the obtained laser frequency drift to achieve fine tuning of the laser frequency, which well solves the problem of complex control system when the existing tunable laser adopts phase-locked frequency stabilization, and has a simple optical path structure and strong anti-interference ability.

Claims

1. A laser frequency stabilization device based on etalon frequency measurement technology, characterized in that: include: A laser light source emission modulation component, comprising a laser, a signal generator for adjusting the emission frequency of the laser, an acousto-optic modulator arranged in the emission direction of the laser, and a radio frequency signal source connected to the acousto-optic modulator signal; A frequency detection component, comprising a first beam splitter disposed on the light output side of the AOM, an etalon disposed on one light output side of the first beam splitter, a first photodetector disposed on the other light output side of the first beam splitter, and a second photodetector disposed on the light output side of the etalon; A main control device, wherein a signal input end of the main control device is signal-connected to the first photodetector and the second photodetector, and a signal output end of the main control device is signal-connected to the radio frequency signal source and the signal generator.

2. The laser frequency stabilization device according to claim 1, characterized in that: The laser light source emission modulation component also includes an optical isolator arranged between the laser and the acousto-optic modulator.

3. The laser frequency stabilization device according to claim 1, characterized in that: The light-emitting side of the AOM is further provided with a second beam splitter, and the first beam splitter is provided on one of the light-emitting sides of the second beam splitter.

4. The laser frequency stabilization device according to claim 1, characterized in that: The frequency detection component further includes a constant temperature module, and the etalon is arranged in the constant temperature module.

5. A frequency stabilization method for a laser frequency stabilization device as claimed in any one of claims 1 to 4, characterized in that: include: Step 1, collecting spectral data passing through the etalon; Step 2, adjusting the laser operating current and voltage to ensure that the difference between the laser center frequency and the selected etalon interference peak frequency is within the frequency adjustment range of the acousto-optic modulator; Step 3, based on the principle of achieving the highest similarity between the laser center frequency and the interference peak frequency of the standard, the driving signal of the acousto-optic modulator outputted by the RF signal source is changed according to the required laser frequency drift amount demodulated.

6. The frequency stabilization method according to claim 5, characterized in that: The step 2 comprises: using the simulation model to generate spectrum data of the laser of the laser under the current parameter conditions, and by comparing the ratio of the valley heights of the selected etalon interference peak frequency, knowing whether the difference between the current laser center frequency and the selected etalon interference peak frequency is greater than the frequency adjustment range of the acousto-optic modulator; if so, adjusting the laser operating current and voltage parameters so that the difference between the laser center frequency and the selected etalon interference peak frequency is within the frequency adjustment range of the acousto-optic modulator.

7. The frequency stabilization method according to claim 5, characterized in that: In step 3, the center frequency parameter of the laser is continuously adjusted to obtain the laser center frequency with the highest similarity to the frequency of the actually measured standard interference signal, so as to demodulate the required laser frequency drift.

8. The frequency stabilization method according to claim 7, characterized in that: The measured etalon interference signal with the associated amplitude modulation eliminated is obtained by dividing the etalon original signal by the reference light signal.

9. The frequency stabilization method according to claim 8, characterized in that: The collected etalon interference signal can be expressed as: in In the above formula, I i is the input light intensity, F is the fineness of the etalon, R is the reflectivity of the etalon reflection plane, δ is the phase difference between adjacent light beams during interference, θ is the incident angle of the light beam, λ is the laser wavelength, n is the refractive index of the laser transmission medium, and h is the distance between the two reflection surfaces of the etalon.

10. The frequency stabilization method according to claim 7, characterized in that: When changing the value of the laser center frequency in the simulation model, the laser center frequency value is adjusted based on the initial value of the laser center frequency in the simulation model. The minimum change in the frequency parameter is where f FSR is the free spectrum range frequency of the etalon, N FSR is the number of sampling points within the free spectrum of the etalon.

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