Single-step coherent synthetic phase-locked loop system and method based on single probe signal, medium

Abstract

The application discloses a single-step coherent synthesis phase-locked system and method based on a single detection signal, and a medium, and relates to the technical field of laser coherent synthesis. The system comprises a laser module, a synthesis module, a detection module and a control module. The laser module is used for splitting laser into multiple sub-beams and a reference beam. The synthesis module is used for synthesizing the multiple sub-beams into a second beam. The detection module is used for separating the second beam into a third beam and a first beam, and detecting the third beam and the reference beam to obtain a detection signal. The control module is used for acquiring the detection signal, determining phase differences of the sub-beams relative to the reference beam according to the detection signal, and compensating phases of the sub-beams based on the phase differences. The system can realize single-step phase locking, significantly improve the control bandwidth, and has a simple optical structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser coherent synthesis, in particular to a single-step coherent synthesis phase-locked system and method based on a single detection signal, and a medium. BACKGROUND

[0002] Laser coherent synthesis is a technology that realizes high-power output and maintains high beam quality by controlling the phase, polarization and other parameters of multiple laser beams to be synchronized and superimposed. Due to the influence of factors such as thermal effect, mechanical vibration, air flow disturbance and power supply noise, the phase of multiple laser beams changes constantly.

[0003] At present, the related technology mainly adopts random parallel gradient descent method, multi-dithering method and heterodyne method for active phase locking, but the heterodyne method needs each light beam to be heterodyne interfered with the same reference light beam, and uses multiple detectors to obtain the heterodyne signal, which has a complex optical structure and high requirements for beam collimation, and is difficult to be used in a co-aperture synthesis system with complete near-field overlap, while the other methods need multiple iterations to converge, and the control bandwidth is limited. SUMMARY

[0004] In view of the above defects or deficiencies in the related art, it is desirable to provide a single-step coherent synthesis phase-locked system and method based on a single detection signal, and a medium, which can improve the control bandwidth and has a simple optical structure.

[0005] In a first aspect, the present application provides a single-step coherent synthesis phase-locked system based on a single detection signal, which comprises a laser module, a synthesis module, a detection module and a control module, the first end of the synthesis module is connected to the first end of the laser module, the second end of the synthesis module is connected to the first end of the detection module, the second end of the detection module is connected to the second end of the laser module, the third end of the detection module emits a first light beam, the fourth end of the detection module is connected to the first end of the control module, the second end of the control module is connected to the third end of the laser module, and the third end of the control module is connected to the fourth end of the laser module.

[0006] The laser module is used to split a laser beam into multiple sub-beams and a reference light beam; the synthesis module is used to synthesize the multiple sub-beams into a second light beam; the detection module is used to separate the second light beam into a third light beam and the first light beam, and detect the third light beam and the reference light beam to obtain a detection signal; and the control module is used to acquire the detection signal, determine the phase difference of each sub-beam relative to the reference light beam according to the detection signal, and compensate the phase of each sub-beam based on the phase difference.

[0007] Optionally, the probe module in some embodiments of the present application comprises a sampling mirror, a beam splitter, a focusing lens and a photodetector arranged in sequence along the direction of the second light beam, and the sampling mirror and the beam splitter are arranged in parallel;

[0008] The sampling mirror is configured to separate the second light beam into the first light beam and the third light beam, the beam splitter is configured to combine the third light beam and the reference light beam into a fourth light beam and then make the fourth light beam incident on the focusing lens, and the photodetector is configured to collect the probe signal and then transmit the probe signal to the control module.

[0009] Optionally, the control module in some embodiments of the present application comprises a controller, a phase modulator and an acousto-optic modulator, and the phase modulator is arranged on each branch corresponding to each sub-beam, and the acousto-optic modulator is arranged on a branch corresponding to the reference light beam.

[0010] The first end of the controller is connected to the fourth end of the probe module, the second end of the controller is connected to the phase modulator, the third end of the controller is connected to the acousto-optic modulator, and the controller is configured to adjust the action voltage of the phase modulator according to the phase difference.

[0011] Optionally, the laser module in some embodiments of the present application comprises a seed laser source, a first amplifier, a beam splitter, a second amplifier and a collimator arranged in sequence, and the seed laser source is configured to emit the laser, and the beam splitter is configured to split the laser into a plurality of sub-beams and a reference light beam.

[0012] Optionally, the synthesis module in some embodiments of the present application is a multi-aperture coherent synthesis module or a common-aperture coherent synthesis module.

[0013] In a second aspect, the present application provides a single-step coherent synthesis phase-locked method based on a single probe signal, and the method is used for the control module of the system in any one of the first aspect, and the method comprises:

[0014] acquiring a probe signal obtained by the probe module detecting a third light beam and a reference light beam, and determining a phase difference between each sub-beam and the reference light beam according to the probe signal, wherein each sub-beam and the reference light beam are obtained by splitting a laser of the laser module, the third light beam is obtained by separating a second light beam by the probe module, and the second light beam is obtained by synthesizing each sub-beam by the synthesis module;

[0015] compensating for the phase of each sub-beam based on the phase difference.

[0016] Optionally, the probe signal in some embodiments of the present application is obtained by the following formula:

[0017] =

[0018] ;

[0019] In the above formulae, denotes the voltage conversion coefficient of the detection module; denotes the air refractive index, denotes the vacuum permittivity, denotes the light speed; denotes the composite light field corresponding to the second light beam, denotes taking the conjugate of the composite light field; denotes the detection area of the detection module; denotes the power of the reference light beam irradiated onto the detection surface of the detection module, denotes the number of sub-beams, denotes the phase of the reference light beam, denotes the modulation depth, denotes the acousto-optic modulation angular frequency, denotes time; denotes the power of the first sub-beam of the third light beam irradiated onto the detection surface of the detection module, denotes the phase of the first sub-beam of the third light beam, denotes the phase modulation angular frequency of the first sub-beam of the third light beam; denotes the power of the first sub-beam of the third light beam irradiated onto the detection surface of the detection module, denotes the phase of the first sub-beam of the third light beam, denotes the phase modulation angular frequency of the first sub-beam of the third light beam.

[0020] Optionally, the phase difference is obtained by the following formula:

[0021] ;

[0022] ;

[0023] ;

[0024] In the above formulae, denotes the integration time, denotes the first-order Bessel function of the first kind, denotes the imaginary unit.

[0025] Optionally, the synthetic light field in some embodiments of the present application is obtained by the following formula:

[0026] ;

[0027] In the above formula, represents the amplitude of the reference light beam, represents the laser center angle frequency of the laser module, represents the amplitude of the third light beam in the first light beam.

[0028] In a third aspect, the present application provides a computer readable storage medium, the computer readable storage medium stores one or more programs, the one or more programs can be executed by one or more processors to implement the steps of the method in any one of the second aspect.

[0029] From the above technical solutions, the embodiments of the present application have the following advantages:

[0030] The embodiments of the present application provide a single-step coherent synthesis phase-locked system and method based on a single detection signal, a first light beam and a third light beam are separated from a second light beam synthesized by multiple sub-light beams, the first light beam is emitted, that is, a small part of power is taken out to obtain the third light beam, which does not affect the phase change, and then only one sampling of the third light beam and the reference light beam is required to obtain the detection signal, the optical structure is simple, and the reference light beam and the multiple sub-light beams are derived from the same laser, so that the phase difference of each sub-light beam relative to the reference light beam can be determined according to the detection signal, and the phase of each sub-light beam is accurately compensated based on the phase difference, single-step phase-locked is realized, and the control bandwidth is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0032] Figure 1 A structural block diagram of a single-step coherent synthesis phase-locked system based on a single detection signal is provided for the embodiments of the present application;

[0033] Figure 2 A specific example of a single-step coherent synthesis phase-locked system based on a single detection signal is provided for the embodiments of the present application;

[0034] Figure 3A flowchart of a single-step coherent synthetic phase-locked method based on a single probe signal is provided for the embodiments of the present application.

[0035] Figure 4 A comparison test result diagram of a single-step coherent synthetic phase-locked method based on a single probe signal provided for the embodiments of the present application and a multi-dithering method.

[0036] Reference signs:

[0037] 10-single-step coherent synthetic phase-locked system based on a single probe signal, 101-laser module, 1011-seed laser source, 1012-first amplifier, 1013-beam splitter, 1014-second amplifier, 1015-collimator, 102-synthetic module, 103-probe module, 1031-sampling mirror, 1032-beam splitter, 1033-focusing lens, 1034-photodetector, 104-control module, 1041-controller, 1042-phase modulator, 1043-acousto-optic modulator, a-first light beam, b-second light beam, c-third light beam, d-fourth light beam. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0040] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the following embodiments will be described in detail. Figures 1 to 4 The single-step coherent synthetic phase-locked system and method based on a single probe signal, and the medium provided by the embodiments of the present application are described in detail.

[0041] Please refer to Figure 1It is a structural block diagram of a single-step coherent synthetic phase-locked system based on a single probe signal provided by an embodiment of the application. The single-step coherent synthetic phase-locked system 10 based on a single probe signal comprises a laser module 101, a synthetic module 102, a probe module 103, and a control module 104. The first end of the synthetic module 102 is connected to the first end of the laser module 101. The second end of the synthetic module 102 is connected to the first end of the probe module 103. The second end of the probe module 103 is connected to the second end of the laser module 101. The third end of the probe module 103 emits a first light beam a. The fourth end of the probe module 103 is connected to the first end of the control module 104. The second end of the control module 104 is connected to the third end of the laser module 101. The third end of the control module 104 is connected to the fourth end of the laser module 101.

[0042] In actual use, in combination with Figure 2 As shown in the figure, the laser module 101 can split the laser beam into multiple sub-beams and a reference light beam. For example, the number of sub-beams is , ≥1, and the synthetic module 102 can synthesize the multiple sub-beams into a second light beam b. The probe module 103 can separate the second light beam b into a third light beam c and the first light beam a, and detect the third light beam c and the reference light beam to obtain a probe signal. Then, the control module 104 can obtain the probe signal, determine the phase difference of each sub-beam relative to the reference light beam based on the probe signal, and accurately compensate the phase of each sub-beam based on the phase difference, thereby realizing single-step phase locking.

[0043] In some embodiments of the application, the laser module 101 can include, but is not limited to, a seed laser source 1011, a first amplifier 1012, a beam splitter 1013, a second amplifier 1014, and a collimator 1015 distributed in sequence, etc. The seed laser source 1011 can emit a laser beam, and the beam splitter 1013 can split the laser beam into multiple sub-beams and a reference light beam. For example, the synthetic module 102 can be a split-aperture coherent synthetic module or a common-aperture coherent synthetic module, which is more versatile and meets the diversified use requirements.

[0044] In some embodiments of the present application, the detection module 103 can include, but is not limited to, a sampling mirror 1031, a beam splitter 1032, a focusing lens 1033 and a photodetector 1034 arranged in sequence along the direction of the second light beam b, wherein the sampling mirror 1031 and the beam splitter 1032 are arranged in parallel, the sampling mirror 1031 can separate the second light beam b to obtain the first light beam a and the third light beam c, the beam splitter 1032 can combine the third light beam c and the reference light beam into the fourth light beam d and then incident on the focusing lens 1033, and the photodetector 1034 can collect the detection signal and transmit it to the control module 104. For example, the control module 104 can include, but is not limited to, a controller 1041, a phase modulator 1042 and an acousto-optic modulator 1043, wherein the phase modulator 1042 is arranged on the branch corresponding to each sub-beam, the acousto-optic modulator 1043 is arranged on the branch corresponding to the reference light beam, that is, each light beam is applied with a modulation signal of different frequency, wherein the first end of the controller 1041 is connected to the fourth end of the detection module 103, the second end of the controller 1041 is connected to the phase modulator 1042, and the third end of the controller 1041 is connected to the acousto-optic modulator 1043, and the controller 1041 can adjust the action voltage of the phase modulator 1042 according to the phase difference. It should be noted that the modulation angular frequency of the phase modulator 1042 and the modulation angular frequency of the acousto-optic modulator 1043 are both set values, that is, the phase modulator 1042 needs to superimpose the action potential given by the controller 1041 in addition to applying a modulation signal of different frequency to each sub-beam, which is related to the working mechanism of the phase modulator 1042, thereby realizing the phase compensation of each sub-beam, and the acousto-optic modulator 1043 only needs to complete the acousto-optic modulation of the reference light beam. In addition, the detection light path of the detection module 103 in the present embodiment can also adopt a fiber structure, as long as the sampled third light beam c can be coherently combined with the frequency-shifted reference light beam and detected.

[0045] The single-step coherent synthesis phase-locked system based on a single detection signal provided by the present application separates the first light beam and the third light beam from the second light beam synthesized by the plurality of sub-beams, the first light beam is emitted, that is, a small part of power is taken to obtain the third light beam, which does not affect the phase change, and then only one sampling of the third light beam and the reference light beam is needed to obtain the detection signal, the optical structure is simple, and the reference light beam and the plurality of sub-beams are derived from the same laser, thereby the phase difference of each sub-beam relative to the reference light beam can be determined according to the detection signal, and the phase of each sub-beam is accurately compensated based on the phase difference, thereby realizing single-step phase-locked and significantly improving the control bandwidth.

[0046] Based on the foregoing embodiments, the present application provides a single-step coherent synthesis phase-locked method based on a single detection signal, which can be used in Figures 1 to 2The control module 104 of the single-step coherent synthetic phase-locked system 10 based on a single probe signal in the corresponding embodiment. Please refer to Figure 3 FIG. 1 is a flowchart of a single-step coherent synthetic phase-locked method based on a single probe signal provided by an embodiment of the present application, which specifically includes the following steps:

[0047] S101, obtaining a probe signal obtained by detecting a third light beam and a reference light beam by a probe module, and determining a phase difference of each sub-beam relative to the reference light beam according to the probe signal, wherein the sub-beams and the reference light beam are obtained by splitting a laser beam of a laser module, the third light beam is obtained by splitting a second light beam by the probe module, and the second light beam is obtained by synthesizing the sub-beams by a synthetic module.

[0048] In some embodiments of the present application, the probe signal may be obtained by formula (1), that is:

[0049]

[0050] (1)

[0051] In formula (1), represents a voltage conversion coefficient of the probe module; represents an air refractive index, represents a vacuum dielectric constant, represents a light speed; represents a synthetic light field corresponding to the second light beam, represents taking a conjugate of the synthetic light field; represents a detection area of the probe module; represents a power of the reference light beam irradiated onto the detection surface of the probe module, represents a number of sub-beams, represents a phase of the reference light beam, represents a modulation depth, represents an acousto-optic modulation angular frequency, represents time; represents a power of the th sub-beam of the third light beam irradiated onto the detection surface of the probe module, represents a phase of the th sub-beam of the third light beam, represents a phase modulation angular frequency of the th sub-beam of the third light beam, and the phase modulation angular frequencies of the sub-beams are all different. The advantage of this setting is that the sub-beams can be marked by different frequencies, which facilitates subsequent separation of the phase information of the sub-beam corresponding to a specific frequency from the synthetic signal according to the specific frequency, thereby realizing the distinction. ​the phase of the third light beam, the power of the third light beam, the phase of the third light beam, the phase of the third light beam, the phase of the third light beam, the phase modulation angular frequency of the third light beam, may be equal or not equal. Wherein, the power , , represent the amplitude corresponding to each light beam.

[0052] And the synthetic light field can be obtained by formula (2), that is:

[0053] (2)

[0054] In formula (2), represents the amplitude of the reference light beam, represents the laser center angular frequency of the laser module, the amplitude of the third light beam,

[0055] Further, the phase difference can be obtained by formula (3), that is:

[0056]

[0057]

[0058] (3)

[0059] In formula (3), represents the integral time, represents the first-order first-type Bessel function, represents the imaginary unit. In addition, the difference frequency modulation signals and of each light beam can also be and , that is, the angular frequency is .

[0060] S102, compensate the phase of each sub-light beam based on the phase difference.

[0061] In some embodiments of the present application, taking 4 sub-light beams as an example, that is, N=4, the acousto-optic modulation angular frequency is 80MHz, the phase modulation angular frequency of each sub-light beam is 1MHz, 2MHz, 3MHz and 4MHz respectively, and the integral time​ is 1 , i.e. one-step control needs 1 , the test results are shown in Figure 4 , the black dotted line represents the corresponding results of the multi-dithering method, the gray solid line represents the method of the present application, and the horizontal axis time unit is . It can be seen from Figure 4 that the multi-dithering method needs three-step control to complete the locking, and the synthesis efficiency of the method of the present application rises from less than 10% of the initial one-step to more than 99%, realizing single-step phase locking.

[0062] It should be noted that the same steps and the same content in the present embodiment and other embodiments are described with reference to the description in other embodiments, and will not be described here.

[0063] The single-step coherent synthesis phase-locked method based on a single probe signal provided by the present application separates the first light beam and the third light beam from the second light beam synthesized by the multiple sub-beams, the first light beam is emitted, that is, a small part of the power is taken to obtain the third light beam, which does not affect the phase change, and then only one sampling of the third light beam and the reference light beam is needed to obtain the probe signal. The optical structure is simple, and the reference light beam and the multiple sub-beams are derived from the same laser, so that the phase difference of each sub-beam relative to the reference light beam can be determined according to the probe signal, and the phase of each sub-beam is accurately compensated based on the phase difference, realizing single-step phase locking, and significantly improving the control bandwidth.

[0064] As another aspect, the present application provides a computer readable storage medium for storing program code, the program code being used to execute any one of the embodiments of the single-step coherent synthesis phase-locked method based on a single probe signal in the corresponding embodiments. Figure 3

[0065] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and module described above can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0066] ​In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic. For example, the division of the modules is merely a logical function division. There can be another division manner for the actual implementation, for example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different modules can be indirect couplings or communication connections through some interfaces, devices or modules, and can be in electrical, mechanical or other forms.

[0067] In addition, each of the functional modules in the various embodiments of the present application can be integrated in one processing unit, or each of the modules can exist physically, or two or more of the modules can be integrated in one module. The integrated unit can be realized in the form of hardware or in the form of software function units. When the integrated unit is realized in the form of software function units and sold or used as an independent product, it can be stored in a computer readable storage medium.

[0068] Based on such an understanding, the technical solutions of the present application, essentially or in part, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the single-step coherent synthesis phase-locked method based on a single probe signal according to the embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various other media that can store program codes.

[0069] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but it should be considered that any combination of the technical features is within the scope of the present disclosure as long as the combination does not cause contradictions.

[0070] The principles and implementation manners of the present application are described herein by using specific examples, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will have changes. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A single-step coherent synthesis phase-locked loop method based on a single probe signal, characterized in that, The method is used in the control module of a single-step coherent synthesis phase-locked loop system based on a single detection signal. The system includes a laser module, a synthesis module, a detection module, and the control module. The first end of the synthesis module is connected to the first end of the laser module, the second end of the synthesis module is connected to the first end of the detection module, the second end of the detection module is connected to the second end of the laser module, the third end of the detection module emits a first beam, the fourth end of the detection module is connected to the first end of the control module, the second end of the control module is connected to the third end of the laser module, and the third end of the control module is connected to the fourth end of the laser module. The laser module is used to split the laser beam into multiple sub-beams and one reference beam; the combining module is used to combine the multiple sub-beams into a second beam; the detection module includes a sampling mirror, a beam splitter, a focusing lens, and a photodetector arranged sequentially along the emission direction of the second beam. The sampling mirror and the beam splitter are arranged in parallel. The sampling mirror is used to separate the second beam into a third beam and the first beam. The beam splitter is used to combine the third beam and the reference beam into a fourth beam and incident on the focusing lens. The photodetector is used to collect the detection signal of the fourth beam and transmit it to the control module; the control module includes a controller, a phase modulator, and an acousto-optic modulator. The phase modulator is provided on the branch corresponding to each sub-beam, and the acousto-optic modulator is provided on the branch corresponding to the reference beam. The phase modulation angular frequency of the phase modulator and the acousto-optic modulation angular frequency of the acousto-optic modulator are both set values. The phase modulation angular frequencies of each sub-beam are different, and the acousto-optic modulation angular frequencies are set. For 80MHz, the number of sub-beams The phase modulation angular frequency of each of the sub-beams is 4. Integration times for 1MHz, 2MHz, 3MHz and 4MHz respectively. 1 The first end of the controller is connected to the fourth end of the detection module, the second end of the controller is connected to the phase modulator, and the third end of the controller is connected to the acousto-optic modulator. The controller is used to adjust the operating voltage of the phase modulator according to the phase difference between each sub-beam and the reference beam. The method includes: acquiring the detection signal, determining the phase difference based on the detection signal, and compensating for the phase of each of the sub-beams based on the phase difference; Among them, the detection signal Obtained through the following formula: = ； In the above formula, This represents the voltage conversion coefficient of the detection module; Indicates the refractive index of air. Represents the vacuum permittivity. Represents the speed of light; This represents the composite optical field corresponding to the second beam. This indicates that the composite optical field is conjugate; This indicates the detection area of ​​the detection module; This represents the power of the reference beam illuminating the detection surface of the detection module. Indicates the number of sub-beams. Indicates the phase of the reference beam. Indicates modulation depth. Indicates the acousto-optic modulation angular frequency. Indicates time; Indicates the third beam The power of the beam illuminating the detection surface of the detection module. Indicates the third beam Phase of the path beam Indicates the third beam The phase modulation angular frequency of the beam; Indicates the third beam The power of the beam illuminating the detection surface of the detection module. Indicates the third beam Phase of the path beam Indicates the third beam The phase modulation angular frequency of the beam; The phase difference Obtained through the following formula: ； ； ； In the above formula, Indicates the integration time. Denotes the first-order Bessel function of the first kind. Represents the imaginary unit; The synthesized light field Obtained through the following formula: ； In the above formula, Indicates the amplitude of the reference beam. This indicates the laser center angular frequency of the laser module. Indicates the third beam The amplitude of the path beam.

2. The method according to claim 1, characterized in that, The laser module includes a seed laser source, a first amplifier, a beam splitter, a second amplifier, and a collimator arranged in sequence. The seed laser source is used to emit the laser, and the beam splitter is used to split the laser into multiple sub-beams and one reference beam.

3. The method according to claim 2, characterized in that, The synthesis module is either a separate aperture coherent synthesis module or a common aperture coherent synthesis module.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores one or more programs, which can be executed by one or more processors to implement the steps of the method according to any one of claims 1 to 3.

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