CN104037608B - Single longitudinal mode laser interlock method and device based on thermoelectric cooling and acousto-optic frequency translation - Google Patents

Abstract

Single longitudinal mode laser interlock method and device based on thermoelectric cooling and acousto-optic frequency translation belong to laser application technique field, the output laser frequency lock of the single longitudinal mode laser using acousto-optic frequency translation technology by many stylobates in thermoelectric cooling of the invention is in the same output laser frequency with reference to single longitudinal mode frequency stabilized carbon dioxide laser, so that all laser output laser have unified frequency values, purpose is to solve the relatively low deficiency of traditional frequency stabilized carbon dioxide laser frequency invariance each other, for ultra-precise laser interferometry provides a kind of new LASER Light Source.

Description

Single longitudinal mode laser interlocking method and device based on thermoelectric cooling and acousto-optic frequency shifting

technical field

The invention belongs to the technical field of laser applications, in particular to a single longitudinal mode laser interlock method and device based on thermoelectric cooling and acousto-optic frequency shifting.

Background technique

In recent years, ultra-precision measurement and processing technologies represented by lithography machines and CNC machine tools have developed towards large-scale, high-precision, multi-space degrees of freedom simultaneous measurement, and the total laser power consumption of the laser interferometry system has increased sharply. The output laser power exceeds the output laser power of a single frequency-stabilized laser, so it is necessary to use multiple frequency-stabilized lasers for combined measurement at the same time. However, there are differences in the relative frequency stability, laser wavelength value, and wavelength drift direction of different frequency-stabilized lasers, which will bring about the measurement accuracy of different spatial degrees of freedom of the laser interferometry system, and the inconsistent wavelength reference and spatial coordinates. It affects the comprehensive measurement accuracy of the entire multi-dimensional laser interferometry system. In order to ensure the comprehensive measurement accuracy of the laser interferometry system, the frequency consistency of multiple frequency-stabilized lasers used in combination is required to reach 10 ^-8 , so the frequency consistency between frequency-stabilized lasers has become an urgent issue in the development of ultra-precision measurement and processing One of the key issues to be resolved.

The frequency-stabilized laser sources currently used in laser interferometry systems mainly include dual-longitudinal-mode frequency-stabilized lasers, transverse Zeeman frequency-stabilized lasers, and longitudinal Zeeman lasers. The center frequency of the laser gain curve is used as the frequency stabilization reference for such lasers. The reference frequency of frequency stabilization control, while the center frequency of the laser gain curve changes with the working gas pressure and discharge conditions, and the physical parameters of multiple frequency stabilization lasers cannot be highly consistent, so there are differences in the reference frequency of frequency stabilization control , resulting in low frequency consistency of laser output from multiple frequency-stabilized lasers, which can only reach 10 ^-6 -10 ^-7 .

In order to solve the problem of poor frequency consistency between frequency-stabilized lasers, Harbin Institute of Technology proposed a dual-longitudinal-mode laser bias frequency locking method (Chinese Patent Application No. The output laser frequency of the frequency-stabilized laser or the dual-longitudinal-mode laser is used as a reference, and the other multiple dual-longitudinal-mode lasers are locked by a certain value relative to the reference frequency, so that the output lasers of multiple dual-longitudinal-mode lasers have the same wavelength ( frequency), but this method needs to adjust the internal working parameters of the laser during the laser frequency locking process. On the one hand, because the adjustment method is an indirect adjustment, the response speed of the system is relatively slow. There are certain differences, and changes in the internal operating parameters of the laser may have a negative impact on the frequency stability of the laser, and in severe cases, it may even cause the laser to lose lock.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention proposes a single longitudinal mode laser interlocking method based on thermoelectric cooling and acousto-optic frequency shifting. The advantages of frequency-stabilized lasers provide a laser light source with excellent wavelength consistency for ultra-precision processing and measurement technology. The invention also provides a single longitudinal mode laser interlocking device based on thermoelectric cooling and acousto-optic frequency shifting.

The object of the present invention is achieved through the following technical solutions:

A method for interlocking single longitudinal mode lasers based on thermoelectric cooling and acousto-optic frequency shifting, the method comprising the following steps:

(1) Turn on the power of the reference single longitudinal mode frequency-stabilized laser. After preheating and frequency stabilization, the laser outputs a single longitudinal mode laser, and its light wave frequency is denoted as ν _r . This output light is separated by a fiber beam splitter into n≥ 1 channel, denoted as beam X _i , i=1, 2,...,n, respectively used as reference beam for frequency locking of single longitudinal mode laser L _i , i=1, 2,...,n;

(2) Turn on the power of the single longitudinal mode laser L _i , i=1, 2,...,n, all single longitudinal mode lasers enter the preheating process at the same time, measure the temperature value of the current environment, and set the target temperature for preheating accordingly T _set , and T _set is higher than the ambient temperature, use a thermoelectric cooler to heat the laser tube inside the laser, so that the temperature of the laser tube tends to the preset temperature value T _set and reach a thermal equilibrium state, and use a polarizing beam splitter to convert the laser The horizontally polarized and vertically polarized laser components in the laser at the sub-output end of the tube are separated, and their optical powers P _i ¹ , i=1,2,...,n and P _i ² ,i=1,2,...,n are respectively determined by the photoelectric The measurement of detector A and photodetector B shows that the frequency stabilization control module adjusts the positive and negative sum of the working current of the thermoelectric cooler according to the preheating algorithm, so that the power value of the horizontally polarized laser component P _i ¹ =0, i=1, 2,...,n, at this time, the laser light at the main output end and the auxiliary output end of the laser tube is a vertically polarized single longitudinal mode laser;

(3) After the preheating process is over, the single longitudinal mode laser L _i , i=1, 2,...,n enters the frequency stabilization control process, and the frequency stabilization control module further fine-tunes the positive and negative working currents of the thermoelectric cooler, so that the vertical The power value P _i ² of the directly polarized laser component, i=1,2,...,n tends to the maximum value, and the operating current value of the electrothermal device is controlled according to the frequency stabilization control algorithm, so that P _i ² ,i=1,2, …, n is always kept at the maximum value, so that the frequency of the laser tends to a stable value;

(4) Record the laser beam at the main output end of the laser tube as beam T _i , i=1,2,...,n, and the frequency of the beam T _i , i=1,2,...,n is recorded as ν _i , i=1 ,2,...,n, light beam T _i ,i=1,2,...,n enters the acousto-optic frequency shifter S _i ,i=1,2 with working frequency f _i ,i=1,2,...,n ,...,n perform frequency shifting, the frequency of the output laser corresponding to the acousto-optic frequency shifter S _i , i=1,2,...,n is recorded as ν _i +f _i ,i=1,2,...,n, so The acousto-optic frequency shifter S _i , i=1, 2,..., n output laser light is divided into two parts of light with an intensity ratio of 9:1 by a spectroscope, and the part of light with relatively higher intensity is recorded as the output beam Z _i ,i=1,2,...,n, respectively as the output laser light of single longitudinal mode laser L _i ,i=1,2,...,n, the part of light with relatively small intensity is recorded as beam Y _i ,i=1 ,2,...,n;

(5) Optically mix the light beam X _i , i=1, 2,..., n with the light beam Y _i , i=1, 2,..., n respectively to form an optical beat frequency signal, and use a photodetector to convert the optical beat frequency signal to The signal is converted into an electrical signal, and its frequency value Δν _i =ν _i +f _i –ν _r , i=1,2,...,n is measured by the frequency measurement module, and the frequency adjustment module is based on the measured frequency of the optical beat frequency signal The value Δν _i ,i=1,2,…,n, calculates the frequency difference ν _r of beams X _i ,i=1,2,…,n and Y _i ,i=1,2,…,n – ν _i =f _i –Δν _i , _i =1,2,…,n, and the operating frequency f _i ,i=1,2, ...,n is adjusted to ν _r -ν _i , i=1,2,...,n, so that the single longitudinal mode laser L _i ,i=1,2,...,n outputs beam Z _i ,i=1,2, The frequency of ...,n is equal to the frequency of the reference beam X _i , i=1,2,...,n, that is, ν _i +f _i =ν _r , i=1,2,...,n;

(6) Steps (4) to (5) are repeated cyclically, by adjusting the operating frequency f _i , i=1, 2,...,n of the acousto-optic frequency shifter S _i , i=1,2,...,n, so that The frequencies of the output beams Z _i , i=1, 2, . . . , _n of the single longitudinal mode laser L _i , i=1, 2, . . .

A single longitudinal mode laser interlocking device based on thermoelectric cooling and acousto-optic frequency shifting, including a laser power supply A (1), a frequency stabilization status indicator light (2), a reference single longitudinal mode frequency stabilization laser (3), and an optical fiber splitter (4), the laser power supply A (1) and the frequency stabilization status indicator light (2) are all connected to the reference single longitudinal mode frequency stabilization laser (3), and the output end of the reference single longitudinal mode frequency stabilization laser (3) is split with the optical fiber The device (4) is connected to the input terminal, and the device also includes n≥1 single longitudinal mode lasers L _i with the same structure and in parallel relationship, i=1, 2,...,n, where each single longitudinal mode laser L _i , The assembly structure of i=1,2,...,n is: the laser power supply B (15) is connected with the laser tube (5), the laser tube (5) is placed in the heat-conducting metal cavity (13), the laser tube (5) and the heat-conducting The gap between the metal cavities (13) is filled with a heat-conducting silica gel layer (12), and the laser tube temperature sensor (10) is placed in the heat-conducting silica gel layer (12), and is close to the outer wall of the laser tube (5), and the laser tube temperature sensor (10) The output terminal is connected to the frequency stabilization control module (9), the thermoelectric cooler (11) is pasted on the outer wall of the heat-conducting metal chamber (13), and the input terminal of the thermoelectric cooler (11) is connected to the frequency stabilization control module (9) , the ambient temperature sensor (14) is connected with the frequency stabilization control module (9), the polarization beam splitter (6) is placed behind the secondary output end of the laser tube (5), and the two output ends of the polarization beam splitter (6) are respectively placed with photoelectric Detector A (7) and photoelectric detector B (8), the output terminals of both are connected with the frequency stabilization control module (9), and the acousto-optic frequency shifter (16) is placed before the main output terminal of the laser tube (5) , the beamsplitter (17) is placed between the acousto-optic frequency shifter (16) and an input end of the fiber combiner (18), and the other input end of the fiber combiner (18) is connected to the fiber splitter (4 ) connected to one of the output ends, the analyzer (19) is placed between the output end of the fiber combiner (18) and the photodetector C (20), the photodetector C (20), the frequency measurement module (21 ), the frequency adjustment module (22), and the acousto-optic frequency shifter (16) are connected in sequence, and the frequency lock status indicator light (23) is connected with the frequency adjustment module (22).

The present invention has following characteristics and good effect:

(1) The present invention uses an acousto-optic frequency shifter to perform parallel frequency locking on a plurality of single longitudinal mode lasers, and all single longitudinal mode frequency-stabilized lasers output laser light with a uniform frequency value. The frequency consistency of multiple lasers can be as high as 10 ^-9 , which is one to two orders of magnitude higher than the existing method, which is one of the innovative points different from the existing technology.

(2) The present invention uses an acousto-optic frequency shifter to lock multiple single longitudinal mode lasers in parallel. Due to the high frequency adjustment response speed of the acousto-optic frequency shifter, the laser wavelength drift and jump caused by external interference factors can be effectively suppressed. change, thereby improving the stability and environmental applicability of the light source, which is the second innovation point different from the existing technology.

(3) The present invention uses an acousto-optic frequency shifter to lock multiple single longitudinal mode lasers in parallel. Since the frequency adjustment method of the final output laser of the laser belongs to an external adjustment method for the internal laser tube of the laser, it will not It has adverse effects on the frequency stabilization control mechanism of the laser tube, which is conducive to improving the stability of the system and the accuracy of frequency stabilization. This is the third innovation point different from the existing technology.

(4) The present invention uses a thermoelectric cooler to control and adjust the temperature. Because changing the direction of its working current can allow the thermoelectric cooler to generate heat or absorb heat, thereby reducing the dependence on the heat dissipation performance of the environment, it is beneficial to realize the laser tube The rapid control and adjustment of temperature improves the response speed of the control system, which is the fourth innovation point different from the existing technology.

Description of drawings

Fig. 1 is the principle schematic diagram of device of the present invention

Fig. 2 is the schematic diagram of the frequency stabilization structure of the single longitudinal mode laser in the device of the present invention

Fig. 3 is the cross-sectional view of the thermal control mechanical structure of the single longitudinal mode laser in the device of the present invention

Fig. 4 is the closed-loop control functional block diagram of the single longitudinal mode laser preheating process in the device of the present invention

Fig. 5 is the closed-loop control functional block diagram of single longitudinal mode laser frequency stabilization process in the device of the present invention

Fig. 6 is the closed-loop control functional block diagram of the single longitudinal mode laser frequency locking process in the device of the present invention

In the figure, 1 laser power supply A, 2 frequency stabilization status indicator, 3 reference single longitudinal mode frequency stabilization laser, 4 fiber beam splitter, 5 laser tube, 6 polarization beam splitter, 7 photodetector A, 8 photodetector B , 9 frequency stabilization control module, 10 laser tube temperature sensor, 11 thermoelectric cooler, 12 heat-conducting silicone layer, 13 heat-conducting metal cavity, 14 ambient temperature sensor, 15 laser power supply B, 16 acousto-optic frequency shifter, 17 beam splitter, 18 Fiber beam combiner, 19 polarizer, 20 photodetector C, 21 frequency measurement module, 22 frequency adjustment module, 23 frequency lock status indicator.

detailed description

The implementation examples of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, Figure 2 and Figure 3, the single longitudinal mode laser interlock device based on thermoelectric cooling and acousto-optic frequency shifting in the device of the present invention includes a laser power supply A1, a frequency stabilization status indicator light 2, a reference single longitudinal mode stabilization Frequency laser 3, fiber beam splitter 4, laser power supply A1 and frequency stabilization status indicator 2 are all connected to the reference single longitudinal mode frequency stabilization laser 3, the output end of reference single longitudinal mode frequency stabilization laser 3 is connected to the input end of fiber optic beam splitter 4 connection, the device also includes n≥1 single longitudinal mode lasers L _i with the same structure in parallel relationship, i=1,2,...,n, wherein each single longitudinal mode laser L _i ,i=1,2, The assembly structure of ..., n is: the laser power supply B15 is connected to the laser tube 5, the laser tube 5 is placed in the heat-conducting metal cavity 13, the gap between the laser tube 5 and the heat-conducting metal cavity 13 is filled with a heat-conducting silica gel layer 12, and the laser tube temperature sensor 10 is placed in the heat-conducting silica gel layer 12, and is close to the outer wall of the laser tube 5. The output terminal of the laser tube temperature sensor 10 is connected to the frequency stabilization control module 9, and the thermoelectric cooler 11 is attached to the outer wall of the heat-conducting metal cavity 13. The thermoelectric The input terminal of the refrigerator 11 is connected to the frequency stabilization control module 9, the ambient temperature sensor 14 is connected to the frequency stabilization control module 9, the polarization beam splitter 6 is placed behind the output end of the laser tube 5, and the two output terminals of the polarization beam splitter 6 are respectively placed Photodetector A7 and photodetector B8, the output ends of both are connected with the frequency stabilization control module 9, the acousto-optic frequency shifter 16 is placed before the main output end of the laser tube 5, and the beam splitter 17 is placed in the acousto-optic frequency shifter 16 and an input end of the fiber combiner 18, the other input end of the fiber combiner 18 is connected with one of the output ends of the fiber splitter 4, and the polarizer 19 is placed on the output of the fiber combiner 18 Between the photodetector C20 and the photodetector C20, the photodetector C20, the frequency measurement module 21, the frequency adjustment module 22, and the acousto-optic frequency shifter 16 are connected in sequence, and the frequency locking status indicator light 23 is connected to the frequency adjustment module 22.

Since the device includes multiple single longitudinal mode frequency stabilized lasers L ₁ , L ₂ ,...,L _n with the same structure, the working process of these single longitudinal mode frequency stabilized lasers is exactly the same, and only one of the single longitudinal mode frequency stabilized lasers is described below L ₁ describes the working process, and these descriptions are also applicable to other similar single longitudinal mode frequency-stabilized lasers in the device.

When starting to work, turn on the laser power supply A1, the reference single longitudinal mode frequency stabilized laser 3 enters the preheating and frequency stabilization process, when the above process is completed, enable the frequency stabilization status indicator 2, indicating that the reference single longitudinal mode frequency stabilized laser 3 enters In a stable working state, the output laser is single longitudinal mode light, which is coupled into the fiber beam splitter 5 and split into n channels of frequency reference beams, which are denoted as beams X ₁ , X ₂ ,…,X _n , and their frequencies are denoted as ν _r , as a reference frequency for frequency locking of single longitudinal mode lasers L ₁ , L ₂ ,…,L _n .

When the frequency stabilization status indicator 2 is enabled, the laser tube power supply B15 is turned on, and the single longitudinal mode frequency stabilization laser L ₁ enters the preheating process. The frequency stabilization control module 9 sets the target temperature T _set for preheating according to the ambient temperature value measured by the ambient temperature sensor 11, and T _set is higher than the ambient temperature, and T _set is used as the preheating closed-loop control system as shown in Figure 4 At the same time, the actual temperature T _real of the laser tube 5 is measured by the laser tube temperature sensor 10 as a feedback signal, and the frequency stabilization control module 9 calculates the difference between the two, and adjusts the work of the thermoelectric cooler 11 according to the frequency stabilization control algorithm The positive and negative currents and the magnitude of the current heat or cool the laser tube 5 so that its temperature tends to the preset target temperature T _set , and use the polarizing beam splitter 6 to convert the horizontal polarization and vertical polarization of the laser at the output end of the laser tube 5 The laser component is separated, and its optical power P ₁ ¹ and P ₁ ² are measured by the photodetector A7 and photodetector B8 respectively, and the frequency stabilization control module 9 adjusts the operating current value of the thermoelectric cooler 11 according to the preheating algorithm to make the level The power value of the polarized laser component P ₁ ¹ =0, at this time, the laser light at the main output end and the auxiliary output end of the laser tube 5 is vertically polarized single longitudinal mode laser light.

After the preheating process is over, the frequency stabilization control module ₉ switches the single longitudinal mode laser L1 to enter the frequency stabilization control process, and the frequency stabilization control module 9 further fine-tunes the positive and negative sum of the operating current value of the thermoelectric cooler 11, so that the vertically polarized laser component The power value P ₁ ² tends to the maximum value, the maximum value is recorded as P ₁ ^2max , and P ₁ ^2max is used as the reference quantity of the frequency stabilization closed-loop control system shown in Figure 5, and the photodetector B8 is measured in real time to obtain The power value P ₁ ² of the vertically polarized laser component is used as the feedback amount, and the frequency stabilization control module 9 calculates the difference between the two, and controls the positive and negative sum of the operating current value of the thermoelectric cooler 11 according to the frequency stabilization control algorithm, so that P ₁ ² is always kept at the maximum value P ₁ ^2max , so that the frequency of the laser tends to a stable value.

After the frequency stabilization process is _over , the laser L1 enters the frequency locking process, the single longitudinal mode laser at the main output end of the laser tube 5 is used as the input light of the acousto-optic frequency shifter 16, and its frequency is denoted as ν ₁ , the work of the acousto-optic frequency shifter 16 The frequency is denoted as f ₁ , due to the acousto-optic interaction, the frequency of the laser light output by the acousto-optic frequency shifter 16 is ν ₁₊ f ₁ , and the beam is then separated into two parts with an intensity of 9:1 by the beam splitter 17, where the intensity is relatively The larger part of light is recorded as beam Z1, which is the output laser light _{of single} longitudinal mode laser L1, and the part of light with relatively smaller intensity is recorded as beam _Y1 , and this beam and beam X1 are coupled into the optical fiber by fiber combiner ₁₈ Synthesized into a bunch of coaxial light beams, the coaxial light beams pass through the analyzer 19 to form an optical beat frequency signal, after photoelectric conversion by the photodetector C20, the frequency value Δν ₁ =ν ₁ +f ₁ -ν _r is determined by the frequency Measured by the measurement module 21, and used as the feedback input of the frequency-locked closed-loop control system shown in Figure 6, the reference input is set to zero, and the frequency adjustment module 22 calculates the beam X ₁ according to the difference Δν ₁ between the two The frequency difference with the beam Y ₁ is ν _r – ν ₁ = f ₁ – Δν ₁ , and the driving frequency f ₁ of the acousto-optic frequency shifter 16 is adjusted to ν _r – ν ₁ , so that the laser L ₁ outputs the beam Z The frequency of ₁ (beam Z ₁ has the same frequency as beam Y ₁ ) is equal to the frequency ν _r of the reference beam X ₁ . After the above frequency locking process is completed, the frequency adjustment module 22 enables the frequency locking status indicator light 23 .

When changes in the external environment or other factors cause the frequency of the output laser of the reference single longitudinal mode frequency stabilized laser ₃ or single longitudinal mode laser L1 to change, the above frequency stabilization and locking process will be automatically cycled, by adjusting the operating frequency of the acousto-optic frequency shifter 16 f ₁ , so that the laser output frequency ν ₁ of the single longitudinal mode laser L ₁ is always locked at the reference frequency ν _r . Similarly, the laser frequencies ν ₂ , ν ₃ , ..., ν _n output by the single longitudinal mode lasers L ₂ , L ₃ ,...,L _n are also always locked at the reference frequency ν _r .

Claims (2)

1. a kind of single longitudinal mode laser interlock method based on thermoelectric cooling and acousto-optic frequency translation, it is characterised in that the method include with Lower step：

(1) power supply with reference to single longitudinal mode frequency stabilized carbon dioxide laser is opened, by after preheating and frequency stabilization process, laser exports single longitudinal mode Laser, its frequency of light wave is designated as ν_r, this output light is separated into n >=1 tunnel, is designated as light beam X by fiber optic splitter_i, i=1,2 ..., n, Respectively as single longitudinal mode laser L_i, i=1,2 ..., the reference beam of n Frequency Lockings；

(2) single longitudinal mode laser L is opened_i, the power supply of i=1,2 ..., n, all single longitudinal mode lasers enter warm simultaneously, The temperature value of current environment is measured, the target temperature T of preheating is set accordingly_set, and T_setHigher than environment temperature, using thermoelectric cooling Device is heated to the laser tube inside laser, the temperature of laser tube is tended to predetermined temperature value T_setAnd reach heat Poised state, is divided the horizontal polarization and vertical polarization laser component in laser tube pair output end laser using polarization spectroscope From its luminous power P_i ¹, i=1,2 ..., n and P_i ², i=1,2 ..., n is measured by photodetector A and photodetector B respectively Draw, path length control module adjusts the positive and negative and size of TEC operating current according to preheating algorithm, swash horizontal polarization The performance number P of light component_i ¹=0, i=1,2 ..., n, now the laser of the main output end of laser tube and secondary output end is vertical polarization Single longitudinal mode laser；

(3) after warm terminates, single longitudinal mode laser L_i, i=1,2 ..., n enter path length control process, path length control module The positive and negative and size of TEC operating current is further finely tuned, makes the performance number P of vertical polarization laser component_i ², i=1, 2 ..., n tend to maximum, and the working current value of electrothermal device is controlled according to path length control algorithm, make P_i ², i=1,2 ..., N remains maximum, and then the frequency of laser is tended towards stability numerical value；

(4) laser of the main output end of laser tube is designated as light beam T_i, i=1,2 ..., n, the light beam T_i, i=1,2 ..., n frequencies It is designated as ν_i, i=1,2 ..., n, light beam T_i, i=1,2 ..., it is f that n enters working frequency_i, i=1,2 ..., the acousto-optic frequency shifters of n S_i, i=1,2 ..., n carries out shift frequency, acousto-optic frequency shifters S_i, i=1,2 ..., the frequency of the corresponding output laser of n is designated as ν_i+f_i,i =1,2 ..., n, the acousto-optic frequency shifters S_i, i=1,2 ..., it is 9 that n outputs laser is divided into strength ratio by spectroscope again:The two of 1 The relatively large part light of part light, wherein intensity is designated as output beam Z_i, i=1,2 ..., n, respectively as single longitudinal mode laser Device L_i, the output laser of i=1,2 ..., n, the relatively small part light of intensity is designated as light beam Y_i, i=1,2 ..., n；

(5) by light beam X_i, i=1,2 ..., n respectively with light beam Y_i, i=1,2 ..., n carries out optical frequency mixing and forms optical beat letter Number, optical beat signal is converted into electric signal using photodetector, its frequency values Δ ν_i=ν_i+f_i–ν_r, i=1,2 ..., n Measured by frequency measuring block, the frequency values Δ ν of the optical beat signal that frequency regulation block is obtained according to measurement_i, i=1, 2 ..., n, calculate light beam X_i, i=1,2 ..., n and Y_i, i=1,2 ..., the frequency-splitting ν of n_r–ν_i=f_i–Δν_i, i=1, 2 ..., n, and by acousto-optic frequency shifters S_i, i=1,2 ..., the working frequency f of n_i, i=1,2 ..., n is adjusted to ν_r–ν_i, i=1, 2 ..., n, so that single longitudinal mode laser L_i, i=1,2 ..., n output beams Z_i, i=1,2 ..., the frequency of n is equal to reference light Beam X_i, the frequency of i=1,2 ..., n, i.e. ν_i+f_i=ν_r, i=1,2 ..., n；

(6) circulating repetition step (4) to (5), by adjusting acousto-optic frequency shifters S_i, i=1,2 ..., the working frequency f of n_i, i=1, 2 ..., n, make single longitudinal mode laser L_i, i=1,2 ..., the output beam Z of n_i, i=1,2 ..., the frequency of n is locked in together all the time One frequency values ν_r。

2. it is a kind of single longitudinal mode laser interlock based on thermoelectric cooling and acousto-optic frequency translation, including laser power supply A (1), steady Frequency status indicator lamp (2), with reference to single longitudinal mode frequency stabilized carbon dioxide laser (3), fiber optic splitter (4), laser power supply A (1) and frequency stabilization shape State indicator lamp (2) is connected with reference to single longitudinal mode frequency stabilized carbon dioxide laser (3), with reference to single longitudinal mode frequency stabilized carbon dioxide laser (3) output end and light Fine beam splitter (4) input connection, it is characterised in that also include that n >=1 structure is identical, single longitudinal mode in parallel relationship in device Laser L_i, i=1,2 ..., n, each of which single longitudinal mode laser L_i, i=1,2 ..., the assembling structure of n is：Laser electricity Source B (15) is connected with laser tube (5), and laser tube (5) is placed in heat-conducting metal chamber (13), laser tube (5) and heat-conducting metal chamber (13) heat conduction silicone (12) is filled in the space between, and laser tube temperature sensor (10) is positioned in heat conduction silicone (12), And it is close to laser tube (5) outer wall, the laser tube temperature sensor (10) output termination path length control module (9), thermoelectric cooling Device (11) is fitted on heat-conducting metal chamber (13) outer wall, the TEC (11) input termination path length control module (9), ring Border temperature sensor (14) is connected with path length control module (9), after polarization spectroscope (6) is placed on laser tube (5) pair output end, (6) two output ends of the polarization spectroscope place photodetector A (7) and photodetector B (8), the output of the two respectively End is all connected with path length control module (9), before acousto-optic frequency shifters (16) are placed on laser tube (5) main output end, spectroscope (17) It is placed between acousto-optic frequency shifters (16) and an input of optical-fiber bundling device (18), another of optical-fiber bundling device (18) is defeated Enter end to be connected with one of the output end of fiber optic splitter (4), analyzer (19) be placed on optical-fiber bundling device (18) output end and Between photodetector C (20), photodetector C (20), frequency measuring block (21), frequency regulation block (22), acousto-optic are moved Frequency device (16) is sequentially connected, and frequency-locked state indicator lamp (23) is connected with frequency regulation block (22).