Temperature-control-free double-optical-comb repetition frequency and phase digital locking system

Abstract

A temperature-control-free double-optical-comb repetition frequency and phase digital locking system comprises a double-optical-comb light source module, a phase digital locking module, a phase setting module, a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer, the repetition frequency and phase of the double optical combs are locked through reference signals generated by the controllable direct digital frequency synthesizer, the frequency of the reference signals output by the controllable direct digital frequency synthesizer is adjusted through feedback signals of the first servo controller and the second servo controller when the temperature changes, and frequency and phase locking of the double optical comb optical system is achieved. Reference signal phases generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are controlled through the upper computer, respective control over the two optical comb pulse phases is achieved, a temperature control module is not needed in the system, the complexity of the system is reduced, and the stability and the integration degree of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of digital locking of frequency and phase, and particularly relates to a dual optical comb repetition frequency and phase digital locking system without temperature control. By setting a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer with adjustable frequency and phase, the repetition frequency and phase of the dual optical comb are locked by the reference signals generated by them. When the temperature changes, the frequencies of the reference signals output by the controllable direct digital frequency synthesizers are adjusted through the feedback signals of the first servo controller and the second servo controller, so as to realize the frequency and phase locking of the dual optical comb optical system. And the phases of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are controlled by an upper computer, so as to realize the separate control of the phases of the pulses of the two optical combs. There is no need for a temperature control module in the system, which is beneficial to reducing the system complexity and improving the system stability and integration degree. Background Art

[0002] The emergence of optical frequency combs has established a direct connection between optical frequencies and microwave frequencies. An optical frequency comb is essentially a new mode-locked light source that can generate ultrashort pulses with stable frequencies and a fixed phase relationship between pulse sequences. Due to its excellent time-domain and frequency-domain characteristics, it has important application prospects in the fields of time-frequency metrology, spectroscopy analysis, biomedical measurement, communication technology, etc. Dual optical comb technology uses the comb tooth beat frequency characteristics between two optical combs with slightly different repetition frequencies and performs high-speed and high-resolution precision measurements through an asynchronous scanning method. Therefore, the repetition frequencies and relative phase stabilities of the pulses generated by the two optical combs greatly affect the measurement stability and measurement accuracy. The repetition frequency of the optical comb is greatly affected by the external environmental temperature. In a conventional optical comb system, the optical comb light source system needs to be enclosed in a heat-insulating housing and equipped with a temperature control module to lock the repetition frequency on the reference signal through temperature control. However, the volume and weight of the heat-insulating housing occupy a large part of the optical comb light source and are one of the important obstacles to the miniaturization of the optical comb light source.

[0003] The inventor has learned that in a dual-comb system, the locking of the repetition frequency difference and phase between the two optical combs is extremely important. When the temperature changes, if the temperature control of the optical comb optical system is not carried out, the repetition frequency of the optical comb will change accordingly, and it is very easy to exceed the adjustment range of the repetition frequency locking system, resulting in system unlocking. The inventor believes that in the application of dual optical combs, it is no longer a necessary condition to lock the two optical combs to a fixed reference frequency. It is only necessary to convert the repetition frequency difference and phase of the two optical combs into digital signals and lock them to ensure the normal operation of the dual optical comb system. Therefore, when the temperature changes, by feedback-adjusting the frequency and phase of the reference signal, ensuring that the repetition frequency locking system always operates within the adjustment range can ensure the locking of the repetition frequency and relative phase of the dual optical comb without a temperature control module, which helps to reduce the system complexity and improve the system stability and integration. Currently, there is no dual optical comb repetition frequency and phase digital locking system without temperature control conditions. In view of this, the inventor has completed the present invention. Summary of the Invention

[0004] Aiming at the defects or deficiencies of the prior art, the present invention provides a digital locking system for the repetition frequency and phase of a dual optical comb without temperature control. By setting a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer with adjustable frequency and phase, the repetition frequency and phase of the dual optical comb are locked by the reference signals generated by them. When the temperature changes, the frequency of the reference signal output by the controllable direct digital frequency synthesizer is adjusted through the feedback signals of the first servo controller and the second servo controller to achieve the locking of the frequency and phase of the dual optical comb optical system. And the phase of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer is controlled by the host computer to achieve the separate control of the pulse phases of the two optical combs. There is no temperature control module in the system, which is beneficial to reducing the system complexity and improving the system stability and integration.

[0005] The technical solution of the present invention is as follows:

[0006] A temperature-uncontrolled dual-comb repetition frequency and phase digital locking system, characterized in that it includes a dual-comb light source module, a phase digital locking module and a phase setting module connected in sequence. The dual-comb light source module generates two repetition frequency optical signals for monitoring. The phase digital locking module converts the two repetition frequency optical signals into digital signals, and feedback-controls the first piezoelectric ceramic and the second piezoelectric ceramic in the dual-comb light source module through a first servo controller and a second servo controller, locking the repetition frequency and phase of the two optical combs to the reference signals generated by a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer. The feedback voltage signals of the first servo controller and the second servo controller are connected to the controllable direct digital frequency synthesizer, and slowly change the frequency of the reference signal generated by it when the temperature changes, realizing the locking of the dual-comb under temperature changes. The phase setting module obtains the phase information of the two repetition frequency optical signals, calculates the phase difference, and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer through a host computer, realizing the phase control of the two optical comb pulses.

[0007] The dual-comb light source module includes a first optical comb optical system and a second optical comb optical system. The output end of the first optical comb optical system is connected to the first photodetector in the phase digital locking module through a first monitoring port. The input end of the first optical comb optical system is connected to the first high-voltage amplifier in the digital locking module through a first piezoelectric ceramic. The output end of the second optical comb optical system is connected to the second photodetector in the phase digital locking module through a second monitoring port. The input end of the second optical comb optical system is connected to the second high-voltage amplifier in the digital locking module through a second piezoelectric ceramic.

[0008] The phase digital locking module includes a first analog-to-digital converter connected to the first photodetector and a second analog-to-digital converter connected to the second photodetector. The output end of the first analog-to-digital converter is connected to the first servo controller and a relative phase acquisition unit through a first mixer respectively. The first servo controller is connected to the input end of the first high-voltage amplifier and the first controllable direct digital frequency synthesizer in the phase setting module respectively. The second input end of the first mixer is connected to the first controllable direct digital frequency synthesizer. The output end of the second analog-to-digital converter is connected to the second servo controller and the relative phase acquisition unit through a second mixer respectively. The second servo controller is connected to the input end of the second high-voltage amplifier and the second controllable direct digital frequency synthesizer in the phase setting module respectively. The second input end of the second mixer is connected to the second controllable direct digital frequency synthesizer.

[0009] The phase setting module includes a host computer connected to the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer respectively. The host computer is connected to the output end of the relative phase acquisition unit in the phase digital locking module. The host computer monitors the phase difference signal and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer to achieve phase control.

[0010] The dual optical comb light source module is enclosed in a box body. The first optical comb optical system and the second optical comb optical system are at the same temperature. The first piezoelectric ceramic and the second piezoelectric ceramic change the resonant cavity lengths of the first optical comb optical system and the second optical comb optical system respectively through deformation to achieve the adjustment of the repetition frequency and phase. The difference in the optical comb pulse repetition frequencies generated by the first optical comb optical system and the second optical comb optical system does not exceed the repetition frequency change range caused by the first piezoelectric ceramic and the second piezoelectric ceramic.

[0011] The detection range of the first photodetector covers the optical comb pulse spectrum range generated by the first optical frequency comb optical system, and the detection range of the second photodetector covers the optical comb pulse spectrum range generated by the second optical frequency comb optical system. The voltage output ranges of the first high-voltage amplifier and the second high-voltage amplifier are 0 to 150V.

[0012] The frequency control words and initial phases of the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are adjustable, so as to control the frequencies and phases of the output signals. The first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are connected to ensure that the frequencies of the reference signals output during the locking process are consistent. The output signal frequency range of the first controllable direct digital frequency synthesizer covers the optical comb pulse repetition frequency generated by the first optical comb optical system, and the output signal frequency range of the second controllable direct digital frequency synthesizer covers the optical comb pulse repetition frequency generated by the second optical comb optical system.

[0013] The technical effects of the present invention are as follows: For a dual optical comb repetition frequency and phase digital locking system without temperature control of the present invention, by setting the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer with adjustable frequencies and phases, the repetition frequency and relative phase of the dual optical comb are locked by using the reference signals generated by them. When the temperature changes, the frequencies of the reference signals output by the controllable direct digital frequency synthesizer are adjusted through the feedback signals of the first servo controller and the second servo controller, and the phases of the reference signals output by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are adjusted through the host computer to achieve the setting and locking of the frequencies and phases of the dual optical comb optical system. There is no need for a temperature control module in the system, which is beneficial to reducing the system complexity and improving the system stability and integration.

[0014] The advantages of the present invention compared with the prior art are as follows: (1) There is no need to set up a heat insulation system and a temperature control module, which reduces the system complexity and improves the system integration level. (2) The reference signal frequency is automatically feedback-regulated according to the change of the external temperature, which ensures that the system does not lose lock and at the same time ensures that the repetition frequency of the dual optical combs does not jump, thus improving the system stability. (3) The phase of the dual optical comb pulses can be monitored and changed in real time by the host computer, which ensures that the system is real-time controllable and meets different application requirements. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of a non-temperature-controlled dual optical comb repetition frequency and phase digital locking system for implementing the present invention.

[0016] The description of the reference numerals is as follows: 1 - First optical comb optical system; 2 - First monitoring port; 3 - First piezoelectric ceramic; 4 - Second optical comb optical system; 5 - Second piezoelectric ceramic; 6 - Second monitoring port; 7 - First photodetector; 8 - First analog-to-digital converter; 9 - First mixer; 10 - First servo controller; 11 - First high-voltage amplifier; 12 - Second photodetector; 13 - Second analog-to-digital converter; 14 - Second mixer; 15 - Second servo controller; 16 - Second high-voltage amplifier; 17 - Relative phase acquisition unit; 18 - First controllable direct digital frequency synthesizer; 19 - Second controllable direct digital frequency synthesizer; 20 - Host computer. Detailed Embodiment

[0017] The following describes the present invention in conjunction with the drawings ( Figure 1 ) and embodiments.

[0018] Figure 1 It is a schematic structural diagram of a non-temperature-controlled dual optical comb repetition frequency and phase digital locking system for implementing the present invention. Refer to Figure 1As shown in the figure, a non-temperature-controlled dual-comb repetition frequency and phase digital locking system includes a dual-comb light source module, a phase digital locking module, and a phase setting module connected in sequence. The dual-comb light source module generates two repetition frequency optical signals for monitoring. The phase digital locking module converts the two repetition frequency optical signals into digital signals, and through the first servo controller 10 and the second servo controller 15, feedback controls the first piezoelectric ceramic 3 and the second piezoelectric ceramic 5 in the dual-comb light source module, locking the repetition frequency and phase of the two optical combs to the reference signals generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19. The feedback voltage signals of the first servo controller 10 and the second servo controller 15 are connected to the controllable direct digital frequency synthesizer, slowly changing the frequency of the reference signal it generates when the temperature changes, to achieve dual-comb locking under temperature changes. The phase setting module acquires the phase information of the two repetition frequency optical signals, calculates the phase difference, and controls the phase of the reference signals generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 through the host computer 20 to achieve phase control of the two optical comb pulses.

[0019] The dual-comb light source module includes a first optical comb optical system 1 and a second optical comb optical system 4. The output end of the first optical comb optical system 1 is connected to the first photodetector 7 in the phase digital locking module through the first monitoring port 2. The input end of the first optical comb optical system 1 is connected to the first high-voltage amplifier 11 in the digital locking module through the first piezoelectric ceramic 3. The output end of the second optical comb optical system 4 is connected to the second photodetector 12 in the phase digital locking module through the second monitoring port 6. The input end of the second optical comb optical system 4 is connected to the second high-voltage amplifier 16 in the digital locking module through the second piezoelectric ceramic 5. The phase digital locking module includes a first analog-to-digital converter 8 connected to the first photodetector 7, and a second analog-to-digital converter 13 connected to the second photodetector 12. The output end of the first analog-to-digital converter 8 is connected to the first servo controller 10 and the relative phase acquisition unit 17 respectively through the first mixer 9. The first servo controller 10 is respectively connected to the input end of the first high-voltage amplifier 11 and the first controllable direct digital frequency synthesizer 18 in the phase setting module. The second input end of the first mixer 9 is connected to the first controllable direct digital frequency synthesizer 18. The output end of the second analog-to-digital converter 13 is connected to the second servo controller 15 and the relative phase acquisition unit 17 respectively through the second mixer 14. The second servo controller 15 is respectively connected to the input end of the second high-voltage amplifier 16 and the second controllable direct digital frequency synthesizer 19 in the phase setting module. The second input end of the second mixer 14 is connected to the second controllable direct digital frequency synthesizer 19.

[0020] The phase setting module includes a host computer 20 connected to a first controllable direct digital frequency synthesizer 18 and a second controllable direct digital frequency synthesizer 19 respectively. The host computer 20 is connected to the output end of the relative phase acquisition unit 17 in the phase digital locking module. The host computer 20 monitors the phase difference signal and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 to achieve phase control.

[0021] The dual optical frequency comb light source module is enclosed in a box body. The first optical frequency comb optical system 1 and the second optical frequency comb optical system 4 are at the same temperature. The first piezoelectric ceramic 3 and the second piezoelectric ceramic 5 change the resonant cavity lengths of the first optical frequency comb optical system 1 and the second optical frequency comb optical system 4 respectively through deformation to achieve the adjustment of the repetition frequency and phase. The repetition frequency difference of the optical frequency comb pulses generated by the first optical frequency comb optical system 1 and the second optical frequency comb optical system 4 does not exceed the repetition frequency change range caused by the first piezoelectric ceramic 3 and the second piezoelectric ceramic 5.

[0022] The detection range of the first photodetector 7 covers the optical frequency comb pulse spectrum range generated by the first optical frequency comb optical system 1. The detection range of the second photodetector 12 covers the optical frequency comb pulse spectrum range generated by the second optical frequency comb optical system 4. The voltage output ranges of the first high-voltage amplifier 11 and the second high-voltage amplifier 16 are 0 to 150V.

[0023] The frequency control words and initial phases of the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 are adjustable, so as to control the frequencies and phases of the output signals. The first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 are connected to ensure that the frequencies of the reference signals output during the locking process are the same. The output signal frequency range of the first controllable direct digital frequency synthesizer 18 covers the repetition frequency of the optical frequency comb pulses generated by the first optical frequency comb optical system 1. The output signal frequency range of the second controllable direct digital frequency synthesizer 19 covers the repetition frequency of the optical frequency comb pulses generated by the second optical frequency comb optical system 4.

[0024] A digital locking system for the repetition frequency and phase of a dual-comb without temperature control. By setting a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer with adjustable frequency and phase, the repetition frequency and phase of the dual-comb are locked by the reference signals generated by them. When the temperature changes, the frequencies of the reference signals output by the controllable direct digital frequency synthesizers are adjusted through the feedback signals of the first servo controller and the second servo controller, so as to realize the frequency and phase locking of the dual-comb optical system. And the phases of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are controlled by the host computer to realize the separate control of the phases of the two comb pulses. There is no temperature control module in the system, which is beneficial to reducing the system complexity and improving the system stability and integration.

[0025] Reference Figure 1 As shown in the figure, a digital locking system for the repetition frequency and phase of a dual-comb without temperature control includes a dual-comb light source module, a digital locking module and a phase setting module.

[0026] The dual-comb light source module includes a first comb optical system 1, a second comb optical system 4, a first piezoelectric ceramic 3 and a second piezoelectric ceramic 5. The first comb optical system generates comb pulses, which form a first repetition frequency optical signal through the first monitoring port 2 and then enter the first photodetector 7. The second comb optical system 4 generates comb pulses, which form a second repetition frequency optical signal through the second monitoring port 6 and then enter the second photodetector 12. After receiving the amplified control signals, the first piezoelectric ceramic 3 and the second piezoelectric ceramic 5 deform, respectively changing the resonant cavity lengths of the first comb optical system 1 and the second comb optical system 4 to realize the change of the repetition frequency and phase of the comb pulses. The dual-comb light source module is enclosed in a box body. The temperatures of the first comb optical system 1 and the second comb optical system 4 are the same, and the difference between the repetition frequencies of the comb pulses generated by the first comb optical system 1 and the second comb optical system 4 does not exceed the repetition frequency change range caused by the first piezoelectric ceramic 3 and the second piezoelectric ceramic 5.

[0027] The digital lock module includes a first photodetector 7, a second photodetector 12, a first analog-to-digital converter 8, a second analog-to-digital converter 13, a first mixer 9, a second mixer 14, a first servo controller 10, a second servo controller 15, a first high-voltage amplifier 11, and a second high-voltage amplifier 16. The first repetition frequency optical signal passes through the first photodetector 7 and the first analog-to-digital converter 8 to form a first repetition frequency digital signal. The first mixer 9 mixes the first repetition frequency digital signal with the reference signal sent by the first controllable direct digital frequency synthesizer 18 to form a first mixed signal. The first mixed signal is divided into two paths. One path enters the relative phase acquisition unit 17 to obtain its phase, and the other path enters the first servo controller 10 to form a first control signal and a first feedback signal. The first control signal is amplified by the first high-voltage amplifier 11 and then drives the first piezoelectric ceramic 3 to achieve the repetition frequency locking of the first optical comb optical system 1. The first feedback signal is sent to the first controllable direct digital frequency synthesizer 18 for feedback control of the reference signal frequency. The second repetition frequency optical signal passes through the second photodetector 12 and the second analog-to-digital converter 13 to form a second repetition frequency digital signal. The second mixer 14 mixes the second repetition frequency digital signal with the reference signal sent by the second controllable direct digital frequency synthesizer 19 to form a second mixed signal. The second mixed signal is divided into two paths. One path enters the relative phase acquisition unit 17 to obtain its phase, and the other path enters the second servo controller 15 to form a second control signal and a second feedback signal. The second control signal is amplified by the second high-voltage amplifier 16 and then drives the second piezoelectric ceramic 5 to achieve the repetition frequency locking of the second optical comb optical system 4. The second feedback signal is sent to the second controllable direct digital frequency synthesizer 19 for feedback control of the reference signal frequency. The detection range of the first photodetector 7 covers the optical comb pulse spectral range generated by the first optical frequency comb optical system 1, and the detection range of the second photodetector 12 covers the optical comb pulse spectral range generated by the second optical frequency comb optical system 4. The voltage output range of the first high-voltage amplifier 11 and the second high-voltage amplifier 16 is: 0 - 150V.

[0028] The phase setting module includes a relative phase acquisition unit 17, a first controllable direct digital frequency synthesizer 18, a second controllable direct digital frequency synthesizer 19, and a host computer 20. The phase acquisition unit receives the first mixing signal and the second mixing signal, extracts their phase information, forms a phase difference signal, and sends it to the host computer 20. The host computer monitors and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19. The first controllable direct digital frequency synthesizer 18 receives the first feedback signal, and the second controllable direct digital frequency synthesizer 19 receives the second feedback signal. Since the temperatures of the first optical comb optical system 1 and the second optical comb optical system 4 are the same, the first and second feedback signals are consistent, and the reference signal frequencies generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 are synchronously feedback-controlled to achieve repetition frequency and phase locking under temperature changes. The frequency control words and initial phases of the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 are adjustable, so as to control the frequencies and phases of the output signals. The first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 are connected to ensure that the reference signal frequencies output during the locking process are consistent, and the output signal frequency ranges generated by them cover the optical comb pulse repetition frequencies generated by the first optical comb optical system 1 and the second optical comb optical system 2.

[0029] Specifically, the optical output pulses emitted by the first optical comb optical system 1 are converted by the first photodetector 7 and the first analog-to-digital converter 8 to form a first repetition frequency digital signal. This signal is mixed with the reference signal generated by the first controllable direct digital frequency synthesizer 18 by the first mixer 9 to form a first mixed signal. A part of this signal is input into the first servo controller 10 as an error signal to control the deformation of the first piezoelectric ceramic 3, thereby changing the resonant cavity length of the first optical comb optical system 1, locking its repetition frequency and phase to the reference signal, and achieving the locking of the optical comb repetition frequency and phase. Similarly, the optical output pulses emitted by the second optical comb optical system 4 are converted by the second photodetector 12 and the first analog-to-digital converter 13 to form a second repetition frequency digital signal. This signal is mixed with the reference signal generated by the second controllable direct digital frequency synthesizer 19 by the second mixer 14 to form a second mixed signal. A part of this signal is input into the second servo controller 15 as an error signal to control the deformation of the second piezoelectric ceramic 5, thereby changing the resonant cavity length of the second optical comb optical system 4, and locking its repetition frequency to the reference signal frequency, achieving the locking of the optical comb repetition frequency. The voltage signals of the first servo controller and the second servo controller are respectively sent to the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 as feedback. Another part of the first mixed signal and another part of the second mixed signal enter the relative phase locking unit 17. After the phase difference is obtained through the algorithm, it is sent to the upper computer. The upper computer monitors and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 to achieve the separate control of the relative phases of the two optical combs. When the external temperature changes, the repetition frequencies of the two optical combs will change accordingly. Due to the above locking process, the feedback voltage signals of the first servo controller and the second servo controller will change accordingly. When they exceed the set value, the frequencies of the reference signals generated by the first controllable direct digital frequency synthesizer 18 and the second controllable direct digital frequency synthesizer 19 will synchronously change by a fixed value, and the repetition frequencies and phases of the pulses generated by the two optical combs will be locked to the new reference signal frequencies. The above process is repeated until the amplitude of the feedback voltage signal is lower than the set value. During this process, the frequency of the reference signal changes slowly, and the system stability is better.

[0030] The content not described in detail in the specification of the present invention belongs to the prior art well-known to those skilled in the art. It is hereby pointed out that the above description helps those skilled in the art to understand the present invention, but does not limit the protection scope of the present invention. Any implementation that makes equivalent substitutions, modifications and improvements, and / or simplifies the above description without departing from the essential content of the present invention falls within the protection scope of the present invention.

Claims

1. A digital locking system for the repetition frequency and phase of a non-thermostatically controlled dual optical frequency comb, characterized in that, It includes a dual-comb light source module, a digital locking module and a phase setting module. The dual-comb light source module generates two optical signals with repetitive frequencies for monitoring. The digital locking module converts the two optical signals with repetitive frequencies into digital signals, and feedback-controls the first piezoelectric ceramic and the second piezoelectric ceramic in the dual-comb light source module through a first servo controller and a second servo controller, locking the repetition frequencies and phases of the two optical combs to the reference signals generated by a first controllable direct digital frequency synthesizer and a second controllable direct digital frequency synthesizer. The feedback voltage signals of the first servo controller and the second servo controller are connected to the controllable direct digital frequency synthesizer, and slowly change the frequency of the reference signal it generates when the temperature changes, realizing the dual-comb locking under temperature changes. The phase setting module obtains the phase information of the two optical signals with repetitive frequencies, calculates the phase difference, and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer through a host computer, realizing the phase control of the two optical comb pulses.

2. The dual optical frequency comb repetition rate and phase digital locking system without temperature control according to claim 1, wherein The dual-comb light source module includes a first optical comb optical system, a second optical comb optical system, a first piezoelectric ceramic and a second piezoelectric ceramic. The first optical comb optical system generates optical comb pulses, forms a first optical signal with a repetitive frequency after passing through a first monitoring port, and then shoots it into the first photodetector of the digital locking module. The first piezoelectric ceramic is connected to the first high-voltage amplifier of the digital locking module and receives its driving signal. The second optical comb optical system generates optical comb pulses, forms a second optical signal with a repetitive frequency after passing through a second monitoring port, and then shoots it into the second photodetector of the digital locking module. The second piezoelectric ceramic is connected to the second high-voltage amplifier of the digital locking module and receives its driving signal.

3. The dual optical frequency comb repetition rate and phase digital locking system without temperature control according to claim 1, characterized in that, The digital locking module includes a first photodetector, a second photodetector, a first analog-to-digital converter, a second analog-to-digital converter, a first mixer, a second mixer, a first servo controller, a second servo controller, a first high-voltage amplifier, and a second high-voltage amplifier. The first repetition-frequency optical signal forms a first repetition-frequency digital signal through the first photodetector and the first analog-to-digital converter. The first mixer is used to mix the first repetition-frequency digital signal with a reference signal sent by the first controllable direct digital frequency synthesizer of the phase setting module to form a first mixed signal. The first mixed signal is divided into two paths, one of which enters the relative phase acquisition unit of the phase digital locking module, and the other enters the first servo controller to form a first control signal and a first feedback signal. The first feedback signal is sent to the first controllable direct digital frequency synthesizer. The first high-voltage amplifier amplifies the first control signal and then sends it to the first piezoelectric ceramic to achieve the locking of the repetition frequency and phase of the first optical comb optical system. The second repetition-frequency optical signal forms a second repetition-frequency digital signal through the second photodetector and the second analog-to-digital converter. The second mixer is used to mix the second repetition-frequency digital signal with a reference signal sent by the second controllable direct digital frequency synthesizer of the phase setting module to form a second mixed signal. The second mixed signal is divided into two paths, one of which enters the relative phase acquisition unit of the phase digital locking module, and the other enters the second servo controller to form a second control signal and a second feedback signal. The second feedback signal is sent to the second controllable direct digital frequency synthesizer. The second high-voltage amplifier amplifies the second control signal and then sends it to the second piezoelectric ceramic to achieve the locking of the repetition frequency and phase of the second optical comb optical system.

4. The dual optical frequency comb repetition rate and phase digital locking system without temperature control according to claim 1, wherein The phase setting module includes a relative phase acquisition unit, a first controllable direct digital frequency synthesizer, a second controllable direct digital frequency synthesizer, and a host computer. The phase acquisition unit is used to receive the first mixed signal and the second mixed signal and form a phase difference signal and send it to the host computer. The host computer monitors the phase difference signal and controls the phases of the reference signals generated by the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer to achieve phase control.

5. The dual optical frequency comb repetition rate and phase digital locking system without temperature control according to claim 1, characterized in that, The dual optical comb light source module is enclosed in a box body. The first optical comb optical system and the second optical comb optical system are at the same temperature. The first piezoelectric ceramic and the second piezoelectric ceramic can respectively change the resonant cavity lengths of the first optical comb optical system and the second optical comb optical system through deformation to achieve the adjustment of the repetition frequency and phase. The difference between the optical comb pulse repetition frequencies generated by the first optical comb optical system and the second optical comb optical system does not exceed the repetition frequency change range caused by the first piezoelectric ceramic and the second piezoelectric ceramic.

6. The dual optical frequency comb repetition rate and phase digital locking system without temperature control according to claim 2, wherein The detection range of the first photodetector covers the optical comb pulse spectral range generated by the first optical frequency comb optical system, the detection range of the second photodetector covers the optical comb pulse spectral range generated by the second optical frequency comb optical system, and the voltage output ranges of the first high-voltage amplifier and the second high-voltage amplifier are: 0 to 150V.

7. The dual optical frequency comb repetition rate and phase digital locking system without temperature control according to claim 1, characterized in that, The frequency control words and initial phases of the first controllable direct digital frequency synthesizer and the second controllable direct digital frequency synthesizer are adjustable, so as to control the frequency and phase of the output signal. The first controllable direct digital frequency synthesizer is connected to the second controllable direct digital frequency synthesizer to ensure that the reference signal frequencies output during the locking process are consistent. The output signal frequency range of the first controllable direct digital frequency synthesizer covers the optical comb pulse repetition frequency generated by the first optical frequency comb optical system, and the output signal frequency range of the second controllable direct digital frequency synthesizer covers the optical comb pulse repetition frequency generated by the second optical frequency comb optical system.

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