An optical phase-locked loop device

Abstract

The present invention relates to an optical phase-locked loop device, and belongs to the field of coherent laser preparation methods in atomic physics and quantum optics. An optical phase-locked loop device of the present invention includes: a laser beat frequency module, a microwave mixing module, a frequency and phase detection module, and a loop filter module; the laser beat frequency module obtains a beat frequency signal to be locked, and the microwave mixing module down-converts it to a local oscillator signal, and the frequency and phase detection module compares it with a reference signal to obtain a phase detection signal, and after being processed by the loop filter module, a feedback signal is obtained to control the laser, thereby forming a closed-loop lock of the optical phase-locked loop. The present invention combines mixing by a double-balanced mixer and an up-conversion mixer. When the laser frequency difference is adjusted, the local oscillator signal remains unchanged, so that the optical phase-locked loop always works at the optimal performance, improves the locking band size, and does not generate additional loop phase shift, which is suitable for the preparation of high-performance coherent lasers; the loop filter in the present invention completely replaces the expensive and bulky commercial frequency locking controller.

Description

Technical Field

[0001] The invention relates to an optical phase-locked loop device, and belongs to the field of coherent laser preparation methods in the fields of atomic physics and quantum optics. Background Art

[0002] Phase-coherent lasers have extremely important applications in the frontier research field of light-matter interaction, including: coherent population-trapping atomic clocks, precision spectral measurements, atomic interferometers, etc. In the above applications, it is very necessary to generate two laser beams with a frequency difference between tens of MHz and several GHz and highly coherent phases. For example, in the cold atom interferometer gravimeter of alkali metal rubidium 87 atoms, two coherent laser beams are locked at around 6.834 GHz. The residual phase noise and additional phase shift of the coherent lasers will have an important impact on the accuracy of gravitational acceleration measurement.

[0003] There are currently a variety of methods or technologies for generating phase-coherent lasers, mainly including the following: the first is Bragg diffraction of an acousto-optic modulator, in which the undiffracted zero-order light and the diffracted light constitute a coherent laser. The disadvantage is that the larger the frequency shift, the lower the efficiency. A typical 3GHz acousto-optic modulator has an efficiency of only 5%; the second is electro-optic modulation frequency shift, in which the zero-order light and the sideband constitute a coherent laser. The disadvantage is that the zero-order light and the sideband overlap and are difficult to control separately, and the presence of multiple useless sidebands causes the atoms to produce a large Stark frequency shift, resulting in a systematic error that is difficult to evaluate for quantum precision measurement; the third is injection locking technology and its variants, which generally use microwave modulation to make the main laser produce sidebands, and then the slave laser is injection locked to the required sidebands. The disadvantage is that it is difficult to control, easy to lose lock, and there is a problem of insufficient sideband suppression ratio.

[0004] Compared with the above three methods, the method of using an optical phase-locked loop to phase-lock two laser beams to prepare phase-coherent laser has the advantages of a large locking frequency range, low laser loss power, pure laser without sidebands, and easy use of coherent light spatial separation.

[0005] Existing optical phase-locked loop devices use only one mixer to adjust the frequency difference of the coherent laser by directly adjusting the reference frequency. When the reference frequency changes, the performance of the optical phase-locked loop changes accordingly, causing the residual phase noise of the coherent laser to fluctuate, and will produce unpredictable additional phase shifts in the loop, which introduces additional system errors into the experimental results. In addition, existing optical phase-locked loop devices often use commercial frequency-locked controllers to achieve laser locking, which has problems such as high price and large size, and requires additional high-voltage drivers to control piezoelectric ceramics, limiting the promotion and use of optical phase-locked loops. Summary of the invention

[0006] In view of the problems existing in the existing optical phase-locked loop, the purpose of the present invention is to provide an optical phase-locked loop device, which down-converts the beat frequency signal to be locked into a local oscillator signal and compares it with a reference signal to obtain a phase detection signal, and obtains a feedback signal after loop filtering to control the laser, thereby forming a closed-loop locking of the optical phase-locked loop;

[0007] The objective of the present invention is achieved through the following technical solutions: An optical phase-locked loop device of the present invention comprises: a laser beat frequency module, a microwave mixing module, a frequency and phase discrimination module and a loop filtering module;

[0008] The laser beat frequency module comprises: two semiconductor lasers, a beat frequency optical path, a high-speed detector, a first radio frequency amplifier, a first radio frequency power divider and a spectrum analyzer;

[0009] Preferably, the beat frequency optical path comprises: a reflector and a semi-reflective and semi-mirror mirror;

[0010] One of the semiconductor lasers is a master laser, and the other semiconductor laser is a slave laser to be locked. The lasers emitted by the master laser and the slave laser are combined through the beat frequency optical path and then irradiated onto the high-speed detector to obtain a laser beat frequency signal. The frequency of the laser beat frequency signal is fb. After passing through the first radio frequency amplifier, the laser beat frequency signal is divided into two parts by the first radio frequency power divider: one part is received by the spectrum analyzer to monitor the effect of the optical phase-locked loop device, and the other part is transmitted to the microwave mixing module;

[0011] The microwave mixing module includes: a double-balanced mixer, an up-conversion mixer, a microwave reference signal, a signal source, a first low-pass filter and a second radio frequency amplifier;

[0012] The laser beat signal after passing through the first RF amplifier and the first RF power divider is transmitted to the double-balanced mixer for mixing, the frequency of the microwave reference signal is f1, the frequency of the signal source is f2, the output of the microwave reference signal and the signal source after passing through the up-conversion mixer has a frequency of f1+f2, which serves as another input of the double-balanced mixer, the intermediate frequency output of the double-balanced mixer passes through the first low-pass filter to filter out the high-frequency signal, and is transmitted to the frequency and phase discrimination module as a local oscillator signal after passing through the second RF amplifier;

[0013] Wherein, the frequency of the local oscillator signal is fLO=fb-(f1+f2), and the laser beat frequency signal fb=fLO+f1+f2;

[0014] The frequency and phase detection module includes: a digital phase detector, an analog phase detector, a second radio frequency power divider, a third radio frequency power divider, a radio frequency reference signal, a conditioning circuit and a phase shifter;

[0015] The local oscillator signal is divided into two parts by the second RF power divider: one part enters the digital phase detector, and the other part enters the analog phase detector;

[0016] The RF reference signal, with a frequency of fREF, is divided into two parts by the third RF power divider, one part directly enters the digital phase detector as a reference, and the other part enters the analog phase detector after being phase-shifted by the phase shifter;

[0017] The digital phase detector outputs a digital phase detection signal, which is transmitted to the loop filter module after passing through the conditioning circuit;

[0018] The analog phase detector outputs an analog phase detection signal which is transmitted to the loop filter module;

[0019] The loop filter module includes: an analog phase-discrimination signal conditioning circuit, a digital phase-discrimination signal conditioning circuit, a T-type bias device and piezoelectric ceramics;

[0020] The analog phase-discrimination signal conditioning circuit comprises: a second low-pass filter, an RC filter circuit and an adjustable attenuator;

[0021] The digital phase-comparison signal conditioning circuit comprises: a first proportional-integral circuit, a second proportional-integral circuit and an adjustable high-voltage circuit;

[0022] The first proportional-integral circuit is composed of an operational amplifier, and the second proportional-integral circuit is composed of an operational amplifier;

[0023] The adjustable high-voltage circuit comprises: a voltage reference source, a voltage amplifier, a high-voltage triode, a potentiometer and a resistor, the potentiometer is used to adjust the voltage output, and the output of the adjustable high-voltage circuit is connected to the negative signal terminal of the piezoelectric ceramic;

[0024] The conditioned analog phase detection signal enters the T-type bias device as a current AC feedback signal, and the digital phase detection signal enters the T-type bias device as a current DC feedback signal after passing through the first proportional integration circuit. The current AC signal and the current DC feedback signal are combined through the T-type bias device to form a total current feedback signal to modulate the current of the slave laser;

[0025] After passing through the first proportional-integral circuit and the second proportional-integral circuit, the digital phase-comparison signal is connected to the positive signal end of the piezoelectric ceramic feedback terminal, and forms a piezoelectric ceramic feedback signal with the output of the adjustable high-voltage circuit to modulate the piezoelectric ceramic of the slave laser;

[0026] When an optical phase-locked loop device of the present invention is working, the frequencies of the microwave reference signal and the radio frequency reference signal are both fixed, and the local oscillator signal is adjusted to cause a phase shift change in the laser frequency difference.

[0027] Beneficial effects:

[0028] 1. An optical phase-locked loop device disclosed in the present invention adopts an out-of-loop detection method, that is, the laser beat frequency module uses a frequency meter to directly detect the laser beat frequency signal, and the measurement result is not affected by the circuit inside the loop.

[0029] 2. The present invention discloses an optical phase-locked loop device, in which the frequency and phase detection module uses an analog phase detector and a digital phase detector in a multiplexed manner, combining the advantages of the high bandwidth of the analog phase detector and the large capture band of the digital phase detector; the loop filter includes a piezoelectric ceramic feedback loop and a current feedback loop, wherein the current feedback loop further includes current DC feedback and current AC feedback, combining the advantages of the large frequency tuning range of the piezoelectric ceramic laser, the flexible adjustment of the current DC feedback, and the high bandwidth of the current AC feedback; the performance of the optical phase-locked loop is comprehensively improved to achieve an optical phase-locked loop with ultra-low phase noise.

[0030] 3. The present invention discloses an optical phase-locked loop device, in which a microwave mixing module uses a double-balanced mixer and an up-conversion mixer to perform down-conversion. When the laser frequency difference is changed, the microwave reference signal frequency is not changed, so that the optical phase-locked loop is always fixed at the optimal working point, the locking band range is improved, and there will be no additional phase shift caused by changes in the optical phase-locked loop parameters. It is more suitable for quantum precision measurement experiments and can use a point-frequency microwave source with excellent performance and low price instead of a commercial standard microwave signal source.

[0031] 4. The present invention discloses an optical phase-locked loop device, in which the loop filter is composed of a simple operational amplifier circuit and a voltage amplifier circuit, which avoids the disadvantages of expensive price and large size of commercial general-purpose frequency-locked controllers and high-voltage drivers, and has the advantages of easy adjustment and excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of an optical phase-locked loop device of the present invention;

[0033] Among them, 1-laser beat frequency module, 2-microwave mixing module, 3-frequency and phase detection module, 4-loop filter module;

[0034] Figure 2 It is a schematic diagram of a laser beat frequency module in an optical phase-locked loop device of the present invention;

[0035] Among them, 10 is a master laser, 11 is a slave laser, 12 is a reflector, 13 is a half-reflector and half-mirror, 14 is a high-speed detector, 15 is a first radio frequency amplifier, 16 is a first radio frequency power divider, and 17 is a spectrum analyzer;

[0036] Figure 3 It is a schematic diagram of a microwave mixing module in an optical phase-locked loop device of the present invention;

[0037] Among them, 20 is a double-balanced mixer, 21 is an up-conversion mixer, 22 is a microwave reference signal, 23 is a signal source, 24 is a first low-pass filter, and 25 is a second radio frequency amplifier;

[0038] Figure 4 It is a schematic diagram of a frequency and phase discrimination module in an optical phase-locked loop device of the present invention;

[0039] Among them, 31-a second RF power divider, 32-an analog phase detector, 33-a RF reference signal, 34-a third RF power divider, 35-a phase shifter, 36-a digital phase detector, 37-a conditioning circuit;

[0040] Figure 5 It is a schematic diagram of a loop filter module in an optical phase-locked loop device of the present invention;

[0041] Among them, 41 is an adjustable high-voltage circuit, 42 is a first proportional integration circuit, 43 is a second proportional integration circuit, 44 is an analog phase-comparison signal conditioning circuit, 45 is a piezoelectric ceramic feedback terminal, and 46 is a T-type bias device. DETAILED DESCRIPTION

[0042] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0043] Embodiment 1:

[0044] This embodiment is described by taking the frequency difference of two lasers corresponding to the ground state hyperfine splitting structure spacing of alkali metal rubidium 87 atoms of 6.834 GHz as an example after the optical phase-locked loop is closed.

[0045] like Figure 1 As shown, an optical phase-locked loop device disclosed in this embodiment includes: a laser beat frequency module 1, a microwave mixing module 2, a frequency and phase detection module 3 and a loop filtering module 4;

[0046] The laser beat frequency module 1 obtains the laser beat frequency signal to be locked, and the microwave mixing module 2 down-converts the laser beat frequency signal to a local oscillator signal in the radio frequency band. The local oscillator signal is compared with the reference signal in the frequency and phase detection module 3 to obtain a phase detection signal. The phase detection signal is processed by the loop filter module 4 to obtain a feedback signal to control the laser, thereby forming a closed-loop locking of the optical phase-locked loop.

[0047] The purpose of the laser beat frequency module 1 is to down-convert the 384THz optical frequency band signal that is difficult to process directly into a microwave band signal (6.834GHz) that can be easily processed;

[0048] like Figure 2 As shown, the laser beat frequency module 1 includes: two semiconductor lasers, a beat frequency optical path, a high-speed detector 14, a first radio frequency amplifier 15, a first radio frequency power divider 16 and a spectrum analyzer 17;

[0049] One of the semiconductor lasers is a master laser 10, the power of the laser output by the master laser 10 is 2 mW, and the other semiconductor laser is a slave laser 11 to be locked, the power of the laser output by the slave laser 11 is 2 mW;

[0050] The beat frequency optical path includes: a reflector 12 and a semi-reflective semi-mirror 13;

[0051] The high-speed detector 14 adopts EOT-4000 with a bandwidth of 12 GHz from EOT Corporation of the United States, the first RF amplifier 15 adopts XHLNA6.0G-7.5G from Xinghua Micro-communications Co., Ltd., the first RF power divider 16 adopts ZX10-2-71-S+ from Minicircuit Co., Ltd., and the spectrum analyzer 17 adopts N9000A from Keysight Co.;

[0052] The laser emitted by the main laser 10 is reflected by the reflector 12 and then combined with the laser emitted by the laser 11 at the semi-reflective mirror 13. The combined laser is received by the high-speed detector 14. The difference frequency of the optical frequency signal is responded by the high-speed detector 14 in the GHz band to form a laser beat signal with a frequency of about 6.834 GHz and an amplitude of about -35 dBm. The laser beat signal is amplified by the first RF amplifier 15, and its amplitude is increased to about -5 dBm. It is divided into two parts by the first RF power divider 16. One part has an amplitude of about -8 dBm and is monitored by the spectrum analyzer 17, and the other part also has an amplitude of about -8 dBm and is transmitted to the microwave mixing module 2.

[0053] The purpose of the microwave mixing module 2 is to down-convert the 6.834 GHz microwave signal to the radio frequency band for further processing;

[0054] like Figure 3 As shown, the microwave mixing module 2 includes: a double-balanced mixer 20, an up-conversion mixer 21, a microwave reference signal 22, a signal source 23, a first low-pass filter 24 and a second radio frequency amplifier 25;

[0055] The double-balanced mixer 20 adopts ZMX-10G of Minicircuit, the up-conversion mixer 21 adopts ZX05-U712H-S+ of Minicircuit, the microwave reference signal source 22 adopts UNFS100 point frequency source of Simon Electronics, the frequency f1 is 6.7 GHz, the signal source 23 adopts DDS33600 of Keysight, the frequency f2 is 34 MHz, the first low-pass filter 24 adopts BLP100+ of Minicircuit, and the second RF amplifier 25 adopts ZFL-500LN+ of Minicircuit;

[0056] After the laser beat signal is transmitted to the microwave mixing module 2, it is mixed at the double balanced mixer 20. Another input of the double balanced mixer 20 is the output of the up-conversion mixer 21. The inputs of the up-conversion mixer 21 are respectively the microwave reference signal source 22 and the signal source 23. The intermediate frequency output of the double balanced mixer 20 passes through the first low-pass filter 24 and the second radio frequency amplifier 25, and is transmitted to the frequency and phase detection module 3 as a local oscillator signal. The amplitude of the local oscillator signal is about 5dBm, and the frequency is fLO=fb-(f1+f2), which is around 100MHz.

[0057] like Figure 4 As shown, the frequency and phase detection module 3 includes: a second RF power divider 31, an analog phase detector 32, a RF reference signal 33, a third RF power divider 34, a phase shifter 35, a digital phase detector 36 and a conditioning circuit 37;

[0058] The second RF power divider 31 and the third RF power divider 34 use ZX10-2-12-S+ of Minicircuit, the analog phase detector 32 uses ZRPD-100 of Minicircuit, the RF reference signal 33 is the ultra-low phase noise 100MHz crystal reference STPLLA10-100 of Tongxiang Technology, the shifter 35 uses JSPHS-150+ of Minicircuit, and the digital phase detector 36 uses HMC984 of ADI.

[0059] The conditioning circuit consists of an operational amplifier and a filter to eliminate high-frequency components and voltage offsets in digital electronic chips;

[0060] The local oscillator signal is divided into two parts by the second RF power divider 31: one part enters the LO terminal of the digital phase detector 36, and the other part enters the analog phase detector 32;

[0061] The RF reference signal 33, with a frequency fREF fixed at 100 MHz, is divided into two parts by a third RF power divider 34, one part directly enters the RF end of the digital phase detector 36 as a reference, and the other part enters the analog phase detector 32 after being phase-shifted by the phase shifter 35;

[0062] The digital phase detector 36 outputs a digital phase detection signal, which is transmitted to the loop filter module 4 after passing through the conditioning circuit 37;

[0063] The analog phase detector 32 outputs an analog phase detection signal which is transmitted to the loop filter module 4;

[0064] After the analog phase detection signal and the digital phase detection signal are transmitted to the loop filter module 4, the piezoelectric ceramic feedback signal and the current feedback signal are obtained after loop filtering, and are fed back to the slave laser 11 to control the current and piezoelectric ceramic of the slave laser 11, so that the slave laser 11 and the master laser 10 form an optical phase-locked loop closed-loop feedback;

[0065] like Figure 5 As shown, the loop filter module 4 includes: an analog phase-comparison signal conditioning circuit 44, a digital phase-comparison signal conditioning circuit, a T-type bias device 46, and a piezoelectric ceramic feedback line terminal 45;

[0066] The analog phase-comparison signal conditioning circuit 44 includes: a second low-pass filter, an RC filter circuit and an adjustable attenuator;

[0067] The second low-pass filter uses BLP30+ from Minicircuit;

[0068] The digital phase detection signal conditioning circuit includes: a first proportional integration circuit 42, a second proportional integration circuit 43 and an adjustable high voltage circuit 41;

[0069] The first proportional integral circuit 42 and the second proportional integral circuit 43 are composed of operational amplifiers, and the integral amplifier circuit and the proportional amplifier circuit are composed of OP27 operational amplifiers of ADI Company;

[0070] The adjustable high-voltage circuit 41 includes: a voltage reference source, a voltage amplifier, a high-voltage triode, a potentiometer and a resistor. The voltage output is adjusted by the potentiometer. The output of the adjustable high-voltage circuit 41 is connected to the negative signal end of the piezoelectric ceramic feedback terminal 45.

[0071] The voltage reference source uses LM399 from ADI, the voltage amplifier uses operational amplifier OP27, and the high-voltage transistor uses MPSA42;

[0072] The power supply of the voltage reference source adopts a DC 150V power supply after the mains is filtered by a diode half-bridge and a capacitor;

[0073] The conditioned analog phase detection signal enters the T-type bias device 46 as a current AC feedback signal, and the digital phase detection signal enters the T-type bias device 46 as a current DC feedback signal after passing through the first proportional integration circuit 42. The current AC signal and the current DC feedback signal are combined through the T-type bias device 46 to form a total current feedback signal, which modulates the current of the slave laser.

[0074] After passing through the first proportional-integral circuit 42 and the second proportional-integral circuit 43, the digital phase-comparison signal is connected to the positive signal end of the piezoelectric ceramic feedback terminal 45, and is combined with the output of the adjustable high-voltage circuit 41 to form a piezoelectric ceramic feedback signal to modulate the piezoelectric ceramic of the slave laser 11;

[0075] When an optical phase-locked loop device of the present invention is working, after all components are powered on and preheated for a period of time, the frequency of the master laser 10 is first locked using the saturated absorption spectrum and modulation locking method, and then the spectrum analyzer 17 is observed. According to the frequency of the laser beat signal, the current and piezoelectric ceramics of the slave laser 11 are adjusted to make the laser beat signal near 6.834 GHz, and the piezoelectric ceramic feedback and current feedback are turned off in turn. The parameters of the loop filter module 4 are adjusted to form an optical phase-locked loop closed-loop lock with ultra-low phase noise and extremely low beat signal linewidth between the master laser 10 and the slave laser 11. The locking effect is monitored using the spectrum analyzer 17, and the coherent laser performance after locking is measured.

[0076] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An optical phase-locked loop device, characterized in that: include: A laser beat frequency module (1), a microwave mixing module (2), a frequency and phase discrimination module (3) and a loop filtering module (4); The laser beat frequency module (1) comprises: two semiconductor lasers, a beat frequency optical path, a high-speed detector (14), a first radio frequency amplifier (15), a first radio frequency power divider (16) and a spectrum analyzer (17); One semiconductor laser is a master laser (10), and the other semiconductor laser is a slave laser (11) to be locked. The lasers emitted by the master laser (10) and the slave laser (11) are combined through a beat frequency optical path and irradiated onto a high-speed detector (14) to obtain a laser beat frequency signal. The frequency of the laser beat frequency signal is fb. After passing through a first radio frequency amplifier (15), the laser beat frequency signal is divided into two parts by a first radio frequency power divider (16): one part is received by a spectrum analyzer (17) to monitor the effect of the optical phase-locked loop device, and the other part is transmitted to a microwave mixing module (2); The microwave mixing module (2) comprises: a double-balanced mixer (20), an up-conversion mixer (21), a microwave reference signal (22), a signal source (23), a first low-pass filter (24) and a second radio frequency amplifier (25); The laser beat signal is transmitted to the double-balanced mixer (20) for mixing after passing through the first radio frequency amplifier (15) and the first radio frequency power divider (16); the frequency of the microwave reference signal (22) is f1, the frequency of the signal source (23) is f2, and the output of the microwave reference signal (22) and the signal source (23) after passing through the up-conversion mixer (21) has a frequency of f1+f2, which serves as another input of the double-balanced mixer (20); the intermediate frequency output of the double-balanced mixer (20) passes through the first low-pass filter (24) to filter out the high-frequency signal, and passes through the second radio frequency amplifier (25) and is transmitted to the frequency and phase detection module (3) as a local oscillator signal; Wherein, the frequency of the local oscillator signal is fLO=fb-(f1+f2), and the laser beat frequency signal fb=fLO+f1+f2; The frequency and phase detection module (3) comprises: a digital phase detector (36), an analog phase detector (32), a second radio frequency power divider (31), a third radio frequency power divider (34), a radio frequency reference signal (33), a conditioning circuit (37) and a phase shifter (35); The local oscillator signal is divided into two parts by the second radio frequency power divider (31): one part enters the digital phase detector (36), and the other part enters the analog phase detector (32); A radio frequency reference signal (33) having a frequency of fREF is divided into two parts by a third radio frequency power divider (34), one part directly entering a digital phase detector (36) as a reference, and the other part entering an analog phase detector (32) after being phase-shifted by a phase shifter (35); The digital phase detector (36) outputs a digital phase detection signal, which is transmitted to the loop filter module (4) after passing through the conditioning circuit (37); The analog phase detector (32) outputs an analog phase detection signal which is transmitted to the loop filter module (4); The loop filter module (4) comprises: an analog phase-comparison signal conditioning circuit (44), a digital phase-comparison signal conditioning circuit, a T-type bias device (46) and a piezoelectric ceramic feedback terminal (45); The analog phase-comparison signal conditioning circuit (44) comprises: a second low-pass filter, an RC filter circuit and an adjustable attenuator; The digital phase-comparison signal conditioning circuit comprises: a first proportional integration circuit (42), a second proportional integration circuit (43) and an adjustable high-voltage circuit (41); The first proportional integration circuit (42) is composed of an operational amplifier, and the second proportional integration circuit (43) is composed of an operational amplifier; The adjustable high-voltage circuit (41) comprises: a voltage reference source, a voltage amplifier, a high-voltage triode, a potentiometer and a resistor, the voltage output is adjusted by the potentiometer, and the output of the adjustable high-voltage circuit (41) is connected to the negative signal end of the piezoelectric ceramic feedback terminal (45); The conditioned analog phase detection signal enters the T-type bias device (46) as a current AC feedback signal, and the digital phase detection signal enters the T-type bias device (46) as a current DC feedback signal after passing through the first proportional integration circuit (42). The current AC signal and the current DC feedback signal are combined through the T-type bias device (46) to form a total current feedback signal, which modulates the current of the slave laser (11); After passing through the first proportional integration circuit (42) and the second proportional integration circuit (43), the digital phase detection signal is connected to the positive signal end of the piezoelectric ceramic feedback terminal (45) and the output of the adjustable high-voltage circuit (41) to form a piezoelectric ceramic feedback to modulate the piezoelectric ceramic of the slave laser (11).

2. An optical phase-locked loop device as claimed in claim 1, characterized in that: The beat frequency optical path comprises: a reflector (12) and a semi-reflective and semi-mirror (13).

3. An optical phase-locked loop device as claimed in claim 1 or 2, characterized in that: During operation, the frequencies of the microwave reference signal (22) and the radio frequency reference signal (33) are both fixed and unchanged, and the local oscillator signal is adjusted to cause the laser frequency difference to produce a phase shift change.

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