A continuous phase compensation system and method for atomic interference

Abstract

The application discloses an ultra-high dynamic range continuous phase compensation system and method for atomic interference, and belongs to the technical field of atomic interference precision measurement. The system comprises a vibration sensing module, a digital processing module, a phase-locked loop control module and a laser modulation module; a Raman mirror vibration signal is collected in real time through an accelerometer, is input into an FPGA after differential amplification and ADC conversion, is sequentially subjected to high-pass filtering, low-pass filtering and weighted integral operation based on an atomic interference time domain sensitivity function, and a phase compensation amount caused by vibration is calculated in real time; the phase compensation amount is converted into an analog compensation signal through a DAC and is injected into a phase-locked loop control link, a phase error signal output by a frequency discriminator is combined, a VCO is controlled, an AOM or an EOM is driven to implement continuous phase modulation on Raman laser in the whole process, and thus real-time, high-precision and high-bandwidth compensation of phase noise caused by mirror vibration is realized, and the system has the advantages of large dynamic range and strong environmental adaptability.

Description

Technical Field

[0001] This invention relates to the field of atomic interferometry precision measurement technology, specifically to a continuous phase compensation system and method for atomic interferometers, and more particularly to an ultra-high dynamic range continuous phase compensation system and method for real-time compensation of phase noise caused by Raman mirror vibration. Background Technology

[0002] Atomic interferometry, based on the principle of matter-wave interference, achieves highly sensitive measurements of phase changes by splitting, evolving, and merging atomic wave packets. Compared to traditional optical interferometry, atomic interferometers use atoms with mass as the interference carrier, exhibiting higher sensitivity in measuring inertial quantities such as gravity and angular acceleration, thus holding significant application value in the field of quantum precision measurement. With the development of laser cooling and trapping technologies, devices such as quantum gravimeters and quantum gyroscopes based on the principle of atomic interferometry have been continuously developed, becoming important technical means for high-precision inertial measurement and fundamental physics research.

[0003] Taking a quantum gravimeter as an example, it typically uses ultracold atoms as inertial masses. During the free fall or fountain-like ejection of atoms, an interference sequence of three Raman laser pulses is used to coherently manipulate the atoms, forming a Mach-Zehnder type atomic interference. To achieve stimulated Raman transitions, a dual-frequency laser is usually injected into a vacuum probe, and a Raman mirror located at the bottom of the probe reflects the laser back along its original path, thus forming a pair of coaxial, counter-propagating coherent beams. This Raman mirror actually constitutes the inertial reference plane of the atomic interferometer. Since the phase of the Raman laser in the atomic interference is coupled into the phase of the atomic interference during the atom-photon interaction, if the Raman mirror experiences a small displacement or acceleration disturbance under environmental vibration, this mechanical vibration will be converted into phase noise of the Raman light, directly affecting the contrast of the atomic interference fringes and the accuracy of the measurement results, becoming one of the key factors limiting the sensitivity and long-term stability of the atomic interferometer.

[0004] To reduce the impact of environmental vibrations on the accuracy of atomic interferometry, existing technologies typically employ methods such as mechanical vibration isolation, data post-processing correction, and phase feedforward compensation at specific times.

[0005] Mechanical vibration isolation solutions typically employ passive or active vibration isolation platforms to support and isolate the Raman mirror, reducing the transmission of external vibrations to the mirror. While this approach can attenuate vibration interference to some extent, it usually requires large vibration isolation devices, resulting in a complex system structure and large space requirements, which is detrimental to the miniaturization, integration, and engineering applications of quantum sensors.

[0006] Post-processing correction schemes typically involve acquiring vibration signals from Raman mirrors or their mounting bases using auxiliary sensors such as seismographs and accelerometers, and then calculating the phase shift caused by vibration using the sensitivity function of an atomic interferometer; alternatively, they may directly measure the phase change caused by vibration using auxiliary optical interferometers. Subsequently, after the experimental measurements are completed, the final measured gravitational acceleration or other inertial quantities are calibrated by fitting and correcting the interference fringes or phase-transition probability relationships. This type of method is essentially non-real-time compensation, only correcting the measurement results during the data processing stage. It cannot suppress the damage to interference contrast caused by vibration in real time during the atomic interferometry process, thus limiting its dynamic range under large-amplitude vibration conditions.

[0007] In addition, there is a phase feedforward compensation scheme based on a direct digital frequency synthesizer (DDS) in the existing technology. This scheme typically uses a vibration acquisition device to obtain the vibration information of the mirror in real time. After digital processing, the calculated vibration phase shift is superimposed on the laser phase only at specific Raman pulse moments, especially at the moment of the third Raman pulse, to achieve phase correction. Although this type of scheme is closer to real-time compensation than post-processing correction, its compensation is usually limited to specific moments in the interference sequence rather than covering the entire interference evolution process. At the same time, the DDS output signal is essentially based on digital synthesis, and its phase adjustment is usually in the form of discrete stepping, which has quantization errors and makes it difficult to achieve truly continuous and smooth phase compensation. It still has shortcomings in high dynamic range and high precision application scenarios.

[0008] Therefore, existing technologies suffer from at least the following problems: Firstly, mechanical vibration isolation schemes struggle to balance high performance and miniaturization requirements; secondly, data post-processing schemes lack real-time capabilities and cannot effectively suppress phase noise accumulation during interference; and thirdly, while DDS-based phase feedforward schemes possess some real-time compensation capability, they still suffer from discrete compensation timing, discontinuous phase adjustment, and significant quantization errors. Consequently, there is an urgent need to provide a phase compensation technology with ultra-high dynamic range, high precision, and continuous operation suitable for atomic interferometer systems, particularly quantum gravimeters, to achieve real-time, continuous, and effective compensation for phase errors caused by Raman mirror vibrations, thereby improving the measurement sensitivity, dynamic range, and long-term stability of atomic interferometers in complex environments. Summary of the Invention

[0009] To address the problem that existing atomic interferometers, especially quantum gravimeters, are easily affected by environmental vibrations during use, this invention aims to provide a continuous phase compensation system and method for atomic interferometry. This solution addresses the technical problems of existing mechanical vibration isolation schemes, which are large in size, complex in structure, and not conducive to miniaturization and integration; data post-processing correction schemes, which lack real-time performance and cannot effectively protect interference contrast; and phase feedforward compensation schemes based on direct digital frequency synthesizers (DDS), which can only perform discrete corrections at specific times, have quantization errors, and are difficult to achieve continuous compensation throughout the entire process.

[0010] The present invention further aims to provide a vibration feedback compensation technology solution with ultra-high dynamic range, high precision and continuous operation, which enables real-time detection, real-time calculation and real-time compensation of phase noise introduced by Raman mirror vibration during the Raman pulse sequence of an atomic interferometer, thereby improving the sensitivity, dynamic range and long-term stability of atomic interferometry.

[0011] To achieve the above objectives, the present invention provides the following technical solution.

[0012] In a first aspect, the present invention provides a continuous phase compensation system for atomic interference, comprising a vibration sensing module, a digital processing module, a phase-locked loop control module, and a laser modulation module.

[0013] The vibration sensing module is used to acquire vibration signals corresponding to the vibration of the Raman mirror in real time. The digital processing module, connected to the vibration sensing module, receives the vibration signals, performs digital processing on them, calculates the corresponding phase compensation amount, and converts the phase compensation amount into an analog compensation signal for output. The phase-locked loop control module, connected to both the digital processing module and the laser modulation module, receives a reference frequency signal and a feedback frequency signal, generates a phase error signal reflecting the phase difference between the two, and synthesizes the phase error signal with the analog compensation signal to output a control signal. The laser modulation module, responding to the radio frequency drive signal corresponding to the control signal, performs phase modulation on the atomic interference laser to compensate for the phase noise introduced by the Raman mirror vibration.

[0014] Preferably, the system is used to perform real-time continuous compensation for the vibration of the Raman mirror during the Raman pulse sequence of the atomic interferometer. The Raman pulse sequence is a π / 2-π-π / 2 pulse sequence, and the real-time continuous compensation covers the three Raman pulse cycles, rather than performing phase correction only at a single Raman pulse moment. This configuration allows the phase compensation process to cover the entire evolution of the atomic interferometer, thereby reducing the problem of insufficient compensation caused by compensating only at a single pulse moment.

[0015] In a preferred embodiment, the vibration sensing module includes an accelerometer and a first differential amplifier. The accelerometer is mounted on or fixedly connected to the Raman reflector and is used to measure the mechanical vibration of the Raman reflector in real time. The input terminal of the first differential amplifier is connected to the output terminal of the accelerometer and is used to adjust or amplify the vibration signal output by the accelerometer before outputting it to the digital processing module. By using an accelerometer to directly sense the vibration of the Raman reflector and using the first differential amplifier to perform pre-processing on the weak vibration signal, the effectiveness of the vibration acquisition signal and the accuracy of subsequent processing can be improved.

[0016] In a preferred embodiment, the digital processing module is a field-programmable gate array (FPGA), which integrates an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The ADC converts the analog vibration signal output by the vibration sensing module into a digital vibration signal. The FPGA calculates the phase compensation amount based on the digital vibration signal, and the DAC converts the phase compensation amount into an analog compensation signal. By combining the ADC, FPGA, and DAC, high-speed sampling, real-time calculation, and rapid output of the compensation signal can be achieved, thus meeting the real-time requirements of the atomic interferometer system.

[0017] Furthermore, the digital processing module is configured to sequentially perform high-pass filtering and low-pass filtering on the digital vibration signal to reduce the influence of sensor temperature drift and filter out high-frequency electronic noise and isolate the sensor's mechanical resonant frequency; and based on the phase sensitivity function of the atomic interferometer, perform weighted integration on the filtered vibration signal to calculate the real-time phase compensation amount caused by the vibration. The combination of high-pass and low-pass filtering reduces the impact of sensor drift and high-frequency noise on the compensation calculation; by introducing the phase sensitivity function of the atomic interferometer for weighted integration, the calculation of the phase compensation amount can better conform to the phase evolution law of atomic interferometry.

[0018] In a preferred embodiment, the phase-locked loop (PLL) control module includes a phase-frequency detector (PFD), a second differential amplifier, a proportional-integral (PI) filter, and a voltage-controlled oscillator (VCO). The PFD receives the reference frequency signal and the feedback frequency signal from the VCO, and outputs the phase error signal. The second differential amplifier is connected to both the PFD and the digital processing module, and performs differential amplification and synthesis processing on the phase error signal and the analog compensation signal. The PI filter performs loop filtering and integral adjustment on the synthesized signal, and outputs a drive voltage to the VCO. The VCO outputs a radio frequency (RF) drive signal of the corresponding frequency based on the drive voltage. By injecting the analog compensation signal output from the digital processing module into the PLL control link and synthesizing it with the phase error signal, continuous phase compensation can be achieved while maintaining the PLL's operating state.

[0019] In a preferred embodiment, the laser modulation module includes an acousto-optic modulator (AOM) or an electro-optic modulator (EOM). The output of the voltage-controlled oscillator (VCO) is connected to the drive port of the AOM or EOM to continuously phase modulate the laser beam passing through the AOM or EOM by changing the drive frequency and phase. By using the AOM or EOM as the laser modulation actuator, the electrical compensation signal can be directly converted into a laser phase correction value, achieving real-time continuous modulation of the Raman laser phase of atomic interference.

[0020] A second aspect of the present invention provides a continuous phase compensation method for atomic interference, applied to the continuous phase compensation system described in any of the above embodiments, comprising the following steps: The vibration signal corresponding to the vibration of the Raman mirror is acquired in real time, and the vibration signal is amplified. The amplified vibration signal is converted into a digital vibration signal; The phase compensation amount caused by the vibration is calculated based on the digital vibration signal, and the phase compensation amount is converted into an analog compensation signal; The analog compensation signal is injected into the phase-locked loop control link and synthesized with the phase error signal in the phase-locked loop to generate a control signal for controlling the voltage-controlled oscillator (VCO). The control signal outputs a radio frequency drive signal, and the radio frequency drive signal is used to drive the laser modulator to perform phase modulation on the atomic interference laser in order to compensate for the phase noise introduced by the vibration of the Raman mirror.

[0021] In a preferred embodiment, the step of calculating the phase compensation amount caused by vibration based on the digital vibration signal includes: performing high-pass filtering on the digital vibration signal to eliminate the influence of sensor temperature drift; performing low-pass filtering on the high-pass filtered signal to filter out high-frequency electronic noise and isolate the sensor mechanical resonant frequency; and performing weighted integration on the filtered vibration signal based on the laser effective wave vector and the time-domain sensitivity function of the atomic interferometer to obtain the real-time phase compensation amount.

[0022] Furthermore, in a preferred embodiment, the calculation process of the phase compensation amount includes: recording the vibration acceleration signal acquired in real time by the accelerometer as... The effective wave vector of the laser is denoted as The time-domain sensitivity function of the atomic interferometer is denoted as... The phase drift caused by vibration satisfy: ; in, The time interval between adjacent pulses in the Raman pulse sequence; the digital processing module processes the vibration acceleration signal. The effective wave vector and the time-domain sensitivity function The phase drift caused by the vibration is calculated in real time, and a real-time phase compensation amount is output to compensate for the phase drift. Through this calculation method, the mirror vibration signal can be processed according to the response weights of the atomic interferometer to vibration disturbances at different times, thereby improving the accuracy of the compensation calculation.

[0023] In a preferred embodiment, the method is executed synchronously during the π / 2-π-π / 2 Raman pulse sequence of the atomic interferometer, enabling the laser modulator to continuously modulate the phase of the Raman laser in real time, so that the effective wavefront of the laser and the mechanical vibration of the Raman mirror maintain a real-time synchronous compensation relationship. By synchronously executing the compensation process during the Raman pulse sequence, the compensation effect can be maintained throughout the entire interferometric measurement process, thereby reducing the impact of environmental vibration on the contrast of interference fringes and measurement accuracy.

[0024] Compared with existing technologies, this invention possesses high-bandwidth real-time compensation capabilities. By setting up a vibration sensing module to collect the mechanical vibration signal of the Raman mirror in real time, and using a digital processing module to perform high-speed sampling, digital processing, and phase compensation calculation on the vibration signal, the phase compensation amount is then injected into the phase-locked loop control module in a feedforward manner to control the voltage-controlled oscillator (VCO) to output the corresponding radio frequency drive signal, thereby driving the laser modulation module to perform phase modulation on the atomic interference laser. This invention can perform real-time continuous compensation simultaneously during the three Raman pulses. Compared with data post-processing schemes that perform compensation after obtaining the interference fringes, and schemes that only perform single compensation before and after the third Raman pulse, this invention can respond to external vibration changes more quickly and in real time, significantly reducing system delay and phase noise caused by environmental vibrations.

[0025] This invention also boasts high flexibility and integration. By injecting the phase feedforward compensation signal calculated by the digital processing module into the adjustment link of the phase-locked loop (PLL), this invention combines the low-noise characteristics of the analog PLL with the flexibility of digital processing. Laser phase correction can be achieved solely through electronic control without modifying the complex external optical path. This not only reduces the difficulty of system implementation but also makes it more suitable for the miniaturization, integration, and engineering applications of atomic interferometers, especially quantum gravimeters.

[0026] Meanwhile, this invention improves measurement accuracy and dynamic range. By employing a digital processing architecture combining a high-bit-width ADC, DAC, and FPGA, and utilizing the analog voltage control characteristics of a voltage-controlled oscillator (VCO) to achieve continuous frequency and phase tuning, compared to DDS phase modulation technology limited by digital quantization steps, this invention offers higher signal-to-noise ratio and phase resolution. It can more precisely convert the mechanical noise sensed by the accelerometer into a compensation signal, thereby achieving high dynamic range vibration feedback control. Through these technical means, this invention effectively suppresses low-frequency and some mid-frequency vibration interference, significantly improving the signal-to-noise ratio, measurement sensitivity, and measurement resolution of the quantum sensor.

[0027] Furthermore, this invention enables continuous phase compensation, rather than performing single phase corrections only at specific moments within the interference sequence. Through the coordinated operation of the digital processing module, the phase-locked loop control module, and the laser modulation module, continuous modulation of the laser phase is achieved throughout the entire Raman pulse sequence. This effectively overcomes the discontinuity problem in phase modulation inherent in traditional direct digital frequency synthesis (DDS) schemes, reduces quantization errors caused by digital modulation, and improves the smoothness and continuity of phase compensation. This is particularly important for maintaining the quality of atomic interference signals under complex vibrational environments.

[0028] Furthermore, this invention exhibits good environmental adaptability and long-term stability. By providing real-time, continuous, and effective compensation for phase errors caused by Raman mirror vibration, the impact of complex environmental vibrations on atomic interferometry results can be reduced, improving the measurement stability and environmental adaptability of the atomic interferometer under complex operating conditions. For high-precision quantum gravimeters, this improvement directly affects not only measurement accuracy but also the system's reliability and practical value during long-term operation.

[0029] Furthermore, this invention can be applied not only to high-precision quantum gravimeter systems but also to other atomic interferometry systems, demonstrating broad applicability and promotional value. In other words, this invention is not limited to a specific device form but can be implemented as a continuous phase compensation technology solution for precision atomic interferometry measurements. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the system in Example 1.

[0031] Figure 2 This is a flowchart of the continuous phase compensation system in this embodiment. Detailed Implementation

[0032] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] Example 1.

[0034] like Figure 1 As shown, this embodiment provides an ultra-high dynamic range, continuous phase compensation system for atomic interferometry. This system can be applied to high-precision quantum gravimeter systems as well as other atomic interferometry systems. In this embodiment, the continuous phase compensation system is used to detect, calculate, and compensate for phase noise caused by Raman mirror vibration in real time, thereby improving the environmental adaptability, dynamic range, measurement accuracy, and long-term stability of atomic interferometry.

[0035] In this embodiment, the continuous phase compensation system includes a vibration sensing module, a digital processing module, a phase-locked loop control module, and a laser modulation module. The vibration sensing module is... Figure 1 Module one contains an accelerometer 1 and a first differential amplifier 2. The digital processing module corresponds to... Figure 1 Module two includes the field-programmable gate array 3. The corresponding phase-locked loop control module... Figure 1 Module three includes a frequency and phase detector 4, a second differential amplifier 5, a proportional-integral filter (PI) 6, and a voltage-controlled oscillator (VCO) 7. The laser modulation module corresponds to... Figure 1Module four mainly consists of the laser modulator 8.

[0036] The vibration sensing module includes an accelerometer 1 and a first differential amplifier 2. The accelerometer 1 is mounted on or fixedly connected to the back of the Raman mirror, and is used to measure the mechanical vibration signal of the Raman mirror in real time. Since the raw signal output by the accelerometer 1 is usually weak, in order to improve the signal quality, the first differential amplifier 2 is connected to the output terminal of the accelerometer 1 to adjust or amplify the vibration signal to obtain an analog vibration signal suitable for subsequent digital processing.

[0037] The digital processing module is mainly composed of a field-programmable gate array (FPGA) and integrates an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The output of the first differential amplifier 2 is connected to the input of the ADC in the digital processing module to convert the differentially amplified analog vibration signal into a digital vibration signal, which is then fed into the FPGA logic unit. The FPGA is internally configured with a digital signal processing algorithm to calculate the corresponding phase compensation amount based on the acquired vibration signal. The calculated phase compensation amount is converted into an analog compensation voltage signal and output via the DAC.

[0038] The phase-locked loop (PLL) control module includes a phase-frequency discriminator (PFD) 4, a second differential amplifier 5, a proportional-integral (PI) filter 6, and a voltage-controlled oscillator (VCO) 7. The PFD 4 receives a reference frequency signal Ref and a feedback frequency signal Fvco from the VCO 7, and outputs an initial error signal reflecting the phase difference between the reference frequency signal Ref and the feedback frequency signal Fvco. The first input of the second differential amplifier 5 is connected to the output of the PFD 4, and the second input is connected to the output of the DAC in the digital processing module, used to receive the initial error signal and a real-time analog compensation voltage signal (Vref). The second differential amplifier 5 performs differential amplification and synthesis on the two signals, and outputs the synthesized control signal to the PI 6. The PI 6 performs loop filtering and integral adjustment on the control signal, generates a drive voltage, and outputs it to the VCO 7. The VCO 7 outputs a radio frequency drive signal of the corresponding frequency according to the drive voltage.

[0039] The actuator of the laser modulation module can be an acousto-optic modulator (AOM) or an electro-optic modulator (EOM). In this embodiment, the output of the voltage-controlled oscillator (VCO) 7 is connected to the drive port of the AOM or EOM. By simultaneously changing the drive frequency and phase, the laser beam passing through the AOM or EOM is phase-modulated to cancel the Raman phase noise introduced by the vibration of the Raman mirror.

[0040] This embodiment further illustrates the specific working process of the continuous phase compensation system in a high-precision quantum gravimeter. That is, a continuous phase compensation method used for atomic interferometry, such as... Figure 2 As shown. Within a single measurement cycle, cold atoms are first loaded and cooled to approximately 3 μK using a combination of two-dimensional and three-dimensional magneto-optical traps. Subsequently, ultracold atoms are vertically ejected upwards by moving optical clusters, allowing them to undergo free fall. Before entering the cylindrical magnetically shielded region, the atomic clusters undergo an optical pumping process, using polarization-controlled pump light to polarize the atoms to a magnetically insensitive initial state. Then, Raman velocity-selective pulses are applied, further filtering out atomic clusters with specific axial velocities while maintaining the atoms in a magnetically insensitive state, and using a blow-off light to remove excess background atoms. After entering the magnetically shielded region, the atoms evolve through Mach-Zehnder type matter-wave interference, a process controlled by a π / 2-π-π / 2 Raman laser pulse sequence, with a time interval of T between adjacent pulses.

[0041] During the Raman pulse sequence described above, the continuous phase compensation system of this embodiment synchronously performs feedback compensation for the vibration of the Raman mirror. Specifically, a high-sensitivity accelerometer 1 installed on the back of the Raman mirror first measures the mechanical vibration of the mirror in real time. The vibration signal is amplified by a first differential amplifier 2 and then input to the ADC in the digital processing module, where it is converted into a digital vibration signal at a high sampling rate.

[0042] Subsequently, the FPGA performs cascaded filtering and phase calculation on the digital vibration signal to construct a digital servo control loop. First, to reduce the impact of temperature-induced zero-point drift, an active temperature control structure can be installed outside the accelerometer to establish a constant thermodynamic environment. Simultaneously, the digital vibration signal is first processed by a high-pass filter to eliminate the influence of sensor temperature drift as much as possible. Then, it is processed by a low-pass filter to filter out high-frequency electronic noise and isolate the sensor's mechanical resonant frequency. The vibration signal after the above processing enters the phase calculation module.

[0043] During phase calculation, based on the phase sensitivity theory of atomic interferometers, the FPGA uses digital signal processing algorithms to perform weighted integration on the vibration signal to accurately quantify the phase drift accumulated by the Raman mirror vibration during interference. The formula for calculating the real-time phase correction is: ; in, The vibration acceleration signal is collected in real time by the accelerometer. The effective wave vector of the laser. This is the time-domain sensitivity function of the atomic interferometer. The time-domain sensitivity function is determined by the timing of three Raman pulses and appears as a trapezoidal or triangular waveform in the time domain, representing the contribution weight of vibration noise at different times to the final interference phase. The system calculates the phase drift caused by vibration in real time according to the above formula and outputs a real-time phase compensation amount to counteract the phase drift.

[0044] The FPGA converts the calculated real-time phase compensation amount into an analog compensation voltage via a DAC and transmits it to the second differential amplifier 5 in the phase-locked loop (PLL) control module. The second differential amplifier 5 performs analog synthesis processing on the initial error signal from the phase-frequency discriminator (PFD) 4 and the analog compensation voltage from the digital processing module, and transmits the synthesized composite control signal to the proportional-integral (PI) filter 6. The PI filter 6 performs integral filtering and dynamic adjustment on the composite control signal, outputting a drive voltage to control the voltage-controlled oscillator (VCO) 7. Through this feedforward injection method, the VCO 7 maintains the PLL locked state while superimposing the compensation amount calculated in real-time by the FPGA, thereby outputting an RF drive signal with corresponding frequency and phase changes.

[0045] The radio frequency drive signal further drives the acousto-optic modulator (AOM) or the electro-optic modulator (EOM) to perform real-time phase modulation of the Raman laser, ensuring that the effective wavefront of the laser maintains a real-time synchronous compensation relationship with the mechanical vibration of the Raman mirror. Through this process, the laser phase can be continuously modulated throughout the three Raman pulses, rather than being corrected only once before the third Raman pulse. Therefore, it can effectively suppress phase noise introduced by environmental vibrations and reduce digital quantization errors and system delays.

[0046] After the atomic interference evolution is completed, the population distribution of atoms is extracted by selective detection of the inner ground state. Since the phase noise caused by the vibration of the Raman mirror has been significantly suppressed, the obtained population signal has a high signal-to-noise ratio. The system can deduce the high-precision interference phase difference from the population signal and further calculate the accurate value of gravitational acceleration.

[0047] The continuous phase compensation system described in this embodiment converts mechanical noise sensed by the accelerometer into an electronic compensation signal and performs continuous phase modulation in conjunction with a phase-locked loop control link and a laser modulation module, enabling high-bandwidth real-time compensation. Compared to schemes that perform compensation after obtaining interference fringes or only perform single compensation during the third Raman pulse, this embodiment can respond more quickly to changes in external vibration and significantly reduce system delay and phase noise caused by environmental vibration.

[0048] Meanwhile, this embodiment combines the low-noise characteristics of analog phase-locked loops with the flexibility of digital processing by injecting a phase feedforward compensation signal calculated by FPGA into the adjustment link of the phase-locked loop. Phase correction can be achieved solely through electronic control without modifying the complex external optical path, thus exhibiting high flexibility and integration.

[0049] Furthermore, this embodiment combines a high-bit-width ADC, DAC, and FPGA, and utilizes the analog voltage control characteristics of a voltage-controlled oscillator (VCO) to achieve continuous frequency and phase tuning. Compared to traditional DDS phase modulation technology, which is limited by the digital quantization step, this embodiment has a higher signal-to-noise ratio and phase resolution. It can more precisely convert the mechanical noise sensed by the accelerometer into a compensation signal, thereby achieving high dynamic range vibration feedback control and effectively suppressing low-frequency and some mid-frequency vibration interference, significantly improving the signal-to-noise ratio, measurement sensitivity, and measurement resolution of the quantum sensor.

[0050] It should be understood that the above embodiments are merely one specific embodiment of the present invention, used to illustrate the technical solution of the present invention. Within the scope of the present invention, equivalent substitutions or conventional adjustments made to the specific device forms, connection methods, and control algorithms of each module should be considered to fall within the protection scope of the present invention.

Claims

1. A continuous phase compensation system for atomic interferometry, characterized in that, It includes a vibration sensing module, a digital processing module, a phase-locked loop control module, and a laser modulation module; The vibration sensing module is used to collect vibration signals corresponding to the vibration of the Raman mirror in real time. The digital processing module is connected to the vibration sensing module and is used to receive the vibration signal, perform digital processing on the vibration signal and calculate the corresponding phase compensation amount, and convert the phase compensation amount into an analog compensation signal for output. The phase-locked loop control module is connected to the digital processing module and the laser modulation module respectively. It is used to receive the reference frequency signal and the feedback frequency signal, generate a phase error signal that reflects the phase difference between the two, and synthesize the phase error signal with the analog compensation signal to output the control signal. The laser modulation module is used to respond to the radio frequency drive signal corresponding to the control signal to perform phase modulation on the atomic interference laser in order to compensate for the phase noise introduced by the vibration of the Raman mirror. The system is used to perform real-time continuous compensation for the vibration of the Raman mirror during the Raman pulse sequence of the atomic interferometer, wherein the Raman pulse sequence is a π / 2-π-π / 2 pulse sequence, and the real-time continuous compensation covers three Raman pulse processes; The phase-locked loop control module includes a frequency and phase detector (PFD), a second differential amplifier, a proportional-integral filter (PI), and a voltage-controlled oscillator (VCO). The frequency and phase detector (PFD) is used to receive the reference frequency signal and the feedback frequency signal from the voltage-controlled oscillator (VCO), and output the phase error signal. The second differential amplifier is connected to the phase-frequency detector (PFD) and the digital processing module, respectively, and is used to perform differential amplification and synthesis processing on the phase error signal and the analog compensation signal; The proportional-integral filter (PI) is used to perform loop filtering and integral adjustment on the synthesized signal and output a drive voltage to the voltage-controlled oscillator (VCO). The voltage-controlled oscillator (VCO) is used to output a radio frequency drive signal of the corresponding frequency according to the drive voltage.

2. The continuous phase compensation system for atomic interferometry according to claim 1, characterized in that, The vibration sensing module includes an accelerometer and a first differential amplifier. The accelerometer is mounted on or fixedly connected to the Raman mirror and is used to measure the mechanical vibration of the Raman mirror in real time. The input terminal of the first differential amplifier is connected to the output terminal of the accelerometer and is used to adjust or amplify the vibration signal output by the accelerometer before outputting it to the digital processing module.

3. The continuous phase compensation system for atomic interferometry according to claim 1, characterized in that, The digital processing module is a field-programmable gate array (FPGA), which integrates an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC). The ADC is used to convert the analog vibration signal output by the vibration sensing module into a digital vibration signal. The FPGA is used to calculate the phase compensation amount based on the digital vibration signal. The DAC is used to convert the phase compensation amount into the analog compensation signal.

4. The continuous phase compensation system for atomic interferometry according to claim 3, characterized in that, The digital processing module is configured to sequentially perform high-pass filtering and low-pass filtering on the digital vibration signal to reduce the influence of sensor temperature drift, filter out high-frequency electronic noise, and isolate the sensor's mechanical resonance frequency; and based on the phase sensitivity function of the atomic interferometer, perform weighted integration on the filtered vibration signal to calculate the real-time phase compensation amount caused by the vibration.

5. The continuous phase compensation system for atomic interferometry according to claim 1, characterized in that, The laser modulation module includes an acousto-optic modulator (AOM) or an electro-optic modulator (EOM). The output of the voltage-controlled oscillator (VCO) is connected to the drive port of the AOM or EOM to continuously phase modulate the laser beam passing through the AOM or EOM by changing the drive frequency and phase.

6. A continuous phase compensation method for atomic interference, characterized in that, The application of the continuous phase compensation system according to any one of claims 1 to 5 includes the following steps: The vibration signal corresponding to the vibration of the Raman mirror is acquired in real time, and the vibration signal is amplified. The amplified vibration signal is converted into a digital vibration signal; The phase compensation amount caused by the vibration is calculated based on the digital vibration signal, and the phase compensation amount is converted into an analog compensation signal; The analog compensation signal is injected into the phase-locked loop control link and synthesized with the phase error signal in the phase-locked loop to generate a control signal for controlling the voltage-controlled oscillator (VCO). The control signal outputs a radio frequency drive signal, and the radio frequency drive signal is used to drive the laser modulator to perform phase modulation on the atomic interference laser in order to compensate for the phase noise introduced by the vibration of the Raman mirror.

7. The continuous phase compensation method for atomic interference according to claim 6, characterized in that, The steps for calculating the phase compensation amount caused by vibration based on the digital vibration signal include: The digital vibration signal is subjected to high-pass filtering to eliminate the influence of sensor temperature drift; The high-pass filtered signal is then subjected to low-pass filtering to remove high-frequency electronic noise and isolate the sensor's mechanical resonant frequency. Based on the effective wave vector of the laser and the time-domain sensitivity function of the atomic interferometer, a weighted integral operation is performed on the filtered vibration signal to obtain the real-time phase compensation amount.

8. The continuous phase compensation method for atomic interference according to claim 7, characterized in that, The calculation process of the phase compensation amount includes: recording the vibration acceleration signal collected in real time by the accelerometer as... The effective wave vector of the laser is denoted as The time-domain sensitivity function of the atomic interferometer is denoted as... The phase drift caused by vibration satisfy: in, The time interval between adjacent pulses in the Raman pulse sequence; the digital processing module processes the vibration acceleration signal. The effective wave vector and the time-domain sensitivity function The phase drift caused by the vibration is calculated in real time, and a real-time phase compensation amount is output to counteract the phase drift.

9. The continuous phase compensation method for atomic interference according to claim 6, characterized in that, The method is executed synchronously during the π / 2-π-π / 2 Raman pulse sequence of the atomic interferometer, enabling the laser modulator to continuously modulate the phase of the Raman laser of the atomic interferometer in real time, so that the effective wavefront of the laser and the mechanical vibration of the Raman mirror maintain a real-time synchronous compensation relationship.

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