Laser phase locking device and method for adaptive switching of multiple phase-locked loops
By using a laser phase-locked loop adaptive switching device that combines optical and electronic phase-locked structures, the problem of balancing high precision and stability in laser phase-locked technology is solved. This achieves a balance between high precision and stability in different environments and is suitable for time synchronization and laser phase-locked technology fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF ADVANCED SCI FACILITIES SHENZHEN
- Filing Date
- 2026-01-14
- Publication Date
- 2026-05-19
AI Technical Summary
Existing laser phase-locked loop (PLL) technology struggles to simultaneously achieve high precision and strong stability. It is susceptible to phase jitter and loss of lock due to factors such as environmental vibration, temperature fluctuations, slow cavity length drift, and electronic noise.
A laser phase-locked loop device with adaptive switching using multiple phase-locked loops includes an optical reference source, an RF reference source, a laser to be locked, an optical phase-locked structure, an optical microwave phase-locked structure, and an electronic phase-locked structure. The controller adaptively switches the feedback source of the actuator to form three phase-locked loops, which respectively utilize a balanced optical cross-correlation device, a balanced optical microwave phase detector, and an electronic phase-locked structure to achieve high precision and strong stability.
In different application scenarios, the phase-locked loop automatically switches to balance high precision and strong stability. It can achieve high-precision phase-locking at the level of <10fs when the environment is stable, maintain lock-on without easy interruption when interference increases, and re-capture through electronic pre-locked loop in extreme cases, thus achieving a balance between high precision and stability of the system.
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Figure CN122068355A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of time synchronization and laser phase-locked loop technology, and more particularly to a laser phase-locked loop device and method with adaptive switching of multiple phase-locked loops. Background Technology
[0002] With the development of ultrafast laser science and free-electron laser devices, high-precision time synchronization between laser systems and between laser systems and reference sources has become increasingly critical. For example, in pump-probe experiments, it is often necessary to maintain stable synchronization between laser pulses and external reference signals at the femtosecond or even sub-femtosecond level to ensure the measurement accuracy of ultrafast physical processes. However, laser phase-locked loop systems are often affected by environmental vibrations, temperature fluctuations, cavity length drift, and electronic noise, making them prone to phase jitter and loss of lock.
[0003] Current laser phase-locked loop technology can be broadly classified into three categories: (1) Phase-locked loop (PLL) method based on electronic phase detector: This method converts the locked laser into a microwave signal through photoelectric detection, and then performs electronic phase detection with the radio frequency reference signal to form a PLL. This method is simple to implement, has low hardware cost, and is mature in engineering applications. However, the phase detection sensitivity is limited by the noise of electronic devices and the phase detection resolution, making it difficult to achieve femtosecond-level precision locking.
[0004] (2) Phase-locked method based on balanced optical microwave phase detector: The optical pulse of the laser to be locked and the radio frequency reference signal are simultaneously input into a balanced optical microwave phase detector (BOMPD) to obtain an error signal representing the phase difference. This method has a wide linear region and strong anti-interference capability, so it is widely used. However, its phase detection sensitivity is limited, which makes it difficult to achieve a locking accuracy below 10 fs.
[0005] (3) Phase-locked method based on balanced optical cross-correlator: The locked laser and laser reference signal are input to a balanced optical cross-correlator (BOC) or a two-color balanced optical cross-correlator (TCBOC). The optical cross-correlation technology is used to achieve ultra-high sensitivity phase detection, which can achieve locking jitter of less than 10fs or even higher accuracy. However, its linear region is extremely narrow and it is extremely sensitive to environmental disturbances. In application, it is easy to lose lock due to drift or vibration.
[0006] In existing technologies, laser phase-locked loop methods have difficulty simultaneously achieving both "high precision" and "strong stability".
[0007] Therefore, existing technologies still need improvement and development. Summary of the Invention
[0008] The technical problem to be solved by the present invention is to provide a laser phase-locked loop device and method with adaptive switching of multiple phase-locked loops, in order to address the above-mentioned deficiencies of the prior art. The aim is to solve the problem that the laser phase-locked loop method in the prior art is difficult to simultaneously achieve high precision and strong stability.
[0009] The technical solution adopted by this invention to solve the technical problem is as follows: A laser phase-locked loop device with adaptive switching across multiple phase-locked loops, comprising: An optical reference source, a radio frequency reference source, and a laser to be locked, wherein the optical reference source and the radio frequency reference source are in a synchronized state; An optical phase-locked structure, wherein the input ports of the optical phase-locked structure are respectively connected to the optical reference source and the laser to be locked; An optical microwave phase-locked structure, wherein the input ports of the optical microwave phase-locked structure are respectively connected to the radio frequency reference source and the laser to be locked; An electronic phase-locked loop (PLL) structure, wherein the input ports of the electronic PLL structure are respectively connected to the radio frequency reference source and the laser to be locked; The controller is connected to the output ports of the optical phase-locked structure, the optical microwave phase-locked structure, the electronic phase-locked structure, and the laser to be locked. The actuator is connected to the controller; The controller adaptively switches the feedback source of the actuator based on the phase-locked state of the electronic phase-locked structure, the phase-locked state of the optical phase-locked structure, or the phase-locked state of the optical microwave phase-locked structure.
[0010] The laser phase-locked loop adaptive switching device with multiple phase-locked loops is described above, wherein the sensitivity of the optical phase-locked structure is higher than that of the optical microwave phase-locked structure, and the linear region of the optical phase-locked structure is narrower than that of the optical microwave phase-locked structure.
[0011] The laser phase-locked loop adaptive switching device with multiple phase-locked loops, wherein the optical phase-locked structure adopts a balanced optical cross-correlation device, and the optical microwave phase-locked structure adopts a balanced optical microwave phase detector.
[0012] The laser phase-locked loop adaptive switching device with multiple phase-locked loops, wherein the balanced optical cross-correlator is a monochromatic balanced optical cross-correlator or a dual-color balanced optical cross-correlator.
[0013] The laser phase-locked loop adaptive switching multi-phase-locked loop device, wherein the electronic phase-locked structure includes: A photodetector, the input port of which is connected to the laser to be locked; The frequency and phase detector has its input ports connected to the radio frequency reference source and the output port of the photodetector, respectively.
[0014] In the laser phase-locked loop adaptive switching device, when the optical phase-locked structure reaches the critical state of loop loss, the controller uses the optical microwave phase-locked structure as a feedback source to control the actuator. When the optical microwave phase-locked structure loses its lock, the controller uses the electronic phase-locked structure as a feedback source to control the actuator. Once the optical microwave phase-locked structure is locked, the controller uses the optical phase-locked structure as a feedback source to control the actuator. Once the electronic phase-locked loop structure is locked, the controller uses the optical microwave phase-locked loop structure as a feedback source to control the actuator.
[0015] The laser phase-locked loop adaptive switching multi-phase-locked loop device, wherein the actuator includes: Piezoelectric ceramics are configured to adjust the phase or cavity length of the laser to be locked with high bandwidth and short stroke to compensate for high-frequency phase disturbances or short-term drift. An adjusting motor or thermal mechanism is configured to adjust the phase or cavity length of the laser to be locked with a low bandwidth and a large stroke to compensate for low-frequency phase disturbances or long-term drift.
[0016] A laser phase-locked loop (PLL) method for a laser PLL device with adaptive switching of multiple PLLs as described in any of the above claims, comprising the following steps: After the laser phase-locked loop device is powered on or loses its lock, it locks the electronic phase-locked loop structure based on the electronic phase-locked loop structure. Based on the phase-locked state of the electronic phase-locked structure, the phase-locked state of the optical phase-locked structure, or the phase-locked state of the optical microwave phase-locked structure, the controller switches the feedback source of the actuator.
[0017] A computer device includes a memory and a processor, the memory storing a computer program, wherein the processor executes the computer program to implement the steps of the laser phase-locked loop method as described above.
[0018] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the laser phase-locked loop method as described above.
[0019] Beneficial effects: This application presents three phase-locked loops (PLLs) with different phase-locked loop structures, each exhibiting varying levels of accuracy and anti-interference capabilities. In different application scenarios, the system automatically switches to a specific PLL based on its phase-locked state, serving as the feedback source for the actuator. This allows the laser PLL device to balance high precision and strong stability. Attached Figure Description
[0020] Figure 1 This is a functional principle block diagram of a laser phase-locked loop adaptive switching device in an embodiment of the present invention.
[0021] Figure 2 This is a flowchart of the laser phase-locked method of the laser phase-locked device with adaptive switching of multiple phase-locked loops in an embodiment of the present invention. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0023] Please also refer to Figure 1 This invention provides some embodiments of a laser phase-locked loop device with adaptive switching of multiple phase-locked loops.
[0024] like Figure 1 As shown, the laser phase-locked loop adaptive switching device of the present invention includes: An optical reference source, a radio frequency reference source, and a laser to be locked, wherein the optical reference source and the radio frequency reference source are in a synchronized state; An optical phase-locked structure, wherein the input ports of the optical phase-locked structure are respectively connected to the optical reference source and the laser to be locked; An optical microwave phase-locked structure, wherein the input ports of the optical microwave phase-locked structure are respectively connected to the radio frequency reference source and the laser to be locked; An electronic phase-locked loop (PLL) structure, wherein the input ports of the electronic PLL structure are respectively connected to the radio frequency reference source and the laser to be locked; The controller is connected to the output ports of the optical phase-locked structure, the optical microwave phase-locked structure, the electronic phase-locked structure, and the laser to be locked. The actuator is connected to the controller; The controller adaptively switches the feedback source of the actuator based on the phase-locked state of the electronic phase-locked structure, the phase-locked state of the optical phase-locked structure, or the phase-locked state of the optical microwave phase-locked structure.
[0025] Specifically, the optical reference source is configured to emit a reference laser signal, the radio frequency (RF) reference source is configured to output an RF reference signal, and the laser to be locked is configured to emit a locked laser signal. When the optical and RF reference sources are synchronized, the reference laser signal and the RF reference signal satisfy an equal frequency or integer multiple relationship. The optical and RF reference sources can maintain phase synchronization through a phase-locked loop (PLL). The laser to be locked refers to the laser that needs to be phase-locked, and its phase is locked to the optical or RF reference source. A 1.3 GHz RF reference source can be used. The controller can be an FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processing), or a MCU (Micro Controller Unit), etc.
[0026] An optical reference source and a laser to be locked are connected to an optical phase-locked loop (PLL). The reference laser signal emitted by the optical reference source and the locked laser signal emitted by the laser to be locked are transmitted to the optical PLL. The optical PLL generates a first error signal based on the reference laser signal and the locked laser signal. The optical reference source, the laser to be locked, the optical PLL, and the controller form a first PLL loop. An RF reference source and a laser to be locked are connected to an optical microwave PLL. The RF reference signal emitted by the RF reference source and the locked laser signal emitted by the laser to be locked are transmitted to the optical microwave PLL. The optical microwave PLL generates a second error signal based on the RF reference signal and the locked laser signal. The RF reference source, the laser to be locked, the optical microwave PLL, and the controller form a second PLL loop. An RF reference source and a laser to be locked are connected to an electronic PLL. The RF reference signal emitted by the RF reference source and the locked laser signal emitted by the laser to be locked are transmitted to the electronic PLL. The electronic PLL generates a third error signal based on the RF reference signal and the locked laser signal. A third phase-locked loop is formed by an RF reference source, the laser to be locked, an electronic phase-locked structure, and a controller. Optical, optical-microwave, and electronic phase-locked structures can all serve as feedback sources for the actuator. Based on the phase-locked state, one of these structures is selected and switched as the feedback source, driving the actuator based on one of the first, second, or third error signals. Although one phase-locked structure is chosen as the feedback source and one error signal is selected to drive the actuator, other phase-locked structures remain active, and other error signals are still collected, primarily for monitoring and backup.
[0027] Optical phase-locked loops (PLLs) offer extremely high phase detection sensitivity but have a narrow linear region. In relatively stable environments, they are used to achieve high-precision PLLs with speeds <10 fs. Optical microwave PLLs feature a wide linear region and large dynamic range, allowing them to take over phase locking even under strong interference, temperature fluctuations, or rapid cavity length drift, ensuring no phase loss. Electronic PLLs are suitable for capturing a wide range of frequencies and phases, used for initial locking upon system power-up and for re-capturing when extreme interference causes other phase-locking failures.
[0028] This application presents three phase-locked loops (PLLs) with different phase-locked loop structures, each exhibiting varying levels of accuracy and interference resistance. In different application scenarios, the system automatically switches to a specific PLL based on its phase-locked state, serving as the feedback source for the actuator. This allows the laser PLL device to balance high precision and strong stability.
[0029] In a preferred implementation of this invention, such as Figure 1 As shown, when the optical phase-locked loop reaches the critical state of loop unlocking, the controller uses the optical microwave phase-locked loop as a feedback source to control the actuator; when the optical microwave phase-locked loop is unlocked, the controller uses the electronic phase-locked loop as a feedback source to control the actuator; when the optical microwave phase-locked loop is locked, the controller uses the optical phase-locked loop as a feedback source to control the actuator; when the electronic phase-locked loop is locked, the controller uses the optical microwave phase-locked loop as a feedback source to control the actuator.
[0030] Specifically, the phase-locked loop (PLL) states include locked and unlocked states, and can also reach a critical state of loop unlocking (imminent unlocking). When determining the locked state, it can be based on the error signal not exceeding a threshold and remaining so for a certain period, and the actuator bias being far from the travel boundary. Alternatively, it can be based on a normal output error signal. When determining the unlocked state, it can be based on whether the error signal exceeds a threshold, or whether the actuator bias is at the travel boundary. When determining if the loop unlocking critical state has been reached, it can be based on the error signal not exceeding a threshold, and an abnormal rate of change of the error signal.
[0031] If an optical phase-locked loop (PLL) has high precision, the first PLL containing it has the highest priority. If an optical microwave PLL has high anti-interference capability, the second PLL containing it has a medium priority. If an electronic PLL has the highest anti-interference capability, the third PLL containing it has the lowest priority. When a PLL loses lock or is about to lose lock, the system switches to a lower-priority PLL; when a PLL is locked, the system switches to a higher-priority PLL.
[0032] When the optical phase-locked loop (PLL) loses lock or is about to lose lock, a second PLL is used, with the optical microwave PLL as the feedback source. When the optical microwave PLL loses lock, a third PLL is used, with the electronic PLL as the feedback source. When either the electronic PLL or the optical microwave PLL is locked, a second PLL is used, with the optical microwave PLL as the feedback source.
[0033] In a preferred implementation of this invention, such as Figure 1 As shown, the optical phase-locked structure is configured to obtain a first error signal based on the reference laser of the optical reference source and the locked laser of the laser to be locked; when the first error signal is outside the first linear region or the bias of the actuator is at the travel boundary, the optical phase-locked structure is unlocked; when the first error signal is within the first linear region and the rate of change is abnormal, the optical phase-locked structure is about to be unlocked; when the first error signal is within the first linear region for a preset time and the bias of the actuator is in an area far from the travel boundary, the conditions for locking the optical phase-locked structure are met.
[0034] Specifically, the unlocked state of the optical phase-locked structure and the locked state of the optical microwave phase-locked structure are determined by the first error signal and the bias of the actuator; the impending unlocked state of the optical phase-locked structure is determined by the first error signal.
[0035] When using the first phase-locked loop (PLL), if the first error signal is outside the first linear region, the optical PLL is in a lost-lock state, requiring a switch to the second PLL. The first linear region has a first threshold; if the first error signal exceeds this threshold, it indicates a large error. When the actuator bias is at the travel boundary, the optical PLL is in a lost-lock state, requiring a switch to the second PLL. The actuator bias at the travel boundary indicates a large bias. If the first error signal is within the first linear region and its rate of change is abnormal, the optical PLL is about to lose lock, requiring a switch to the second PLL. Although the first error signal is still within the first linear region, its rate of change is large, potentially exceeding the threshold, indicating that the error is about to significantly expand outside the first linear region. If the first error signal is within the first linear region, its rate of change is normal, and the actuator bias is not at the travel boundary, the first PLL is still used.
[0036] When the second phase-locked loop is used, the first error signal is located in the first linear region and is maintained for a preset time, and the actuator bias is located in the range far from the travel boundary, indicating that the first error signal meets the locking condition and can be switched to the first phase-locked loop.
[0037] In a preferred implementation of this invention, such as Figure 1 As shown, the optical microwave phase-locked structure is configured to obtain a second error signal based on the radio frequency reference signal of the radio frequency reference source and the locked laser of the laser to be locked; when the second error signal is outside the second linear region, the optical microwave phase-locked structure is unlocked.
[0038] Specifically, the unlocking state of the optical microwave phase-locked loop (PLL) is determined by the second error signal. If, when using the second PLL, the second error signal is outside the second linear region, the optical microwave PLL is in an unlocked state, and a switch to the third PLL is required. The second linear region has a second threshold; if the second error signal exceeds this threshold, it indicates a large error. The first linear region is located within the second linear region, and the coverage of the second linear region is wider than that of the first linear region. If the second error signal is within the second linear region but not within the first linear region, the second PLL is still used. If the second error signal is within the first linear region but the preset time has not been reached, the second PLL is still used. If the actuator bias is not located far from the travel boundary (e.g., the actuator bias is located at the travel boundary), the second PLL is still used. The preset time, the first linear region, and the second linear region can be configured and adjusted as needed.
[0039] In a preferred implementation of this invention, such as Figure 1As shown, when the optical microwave phase-locked structure receives a valid second error signal, the electronic phase-locked structure locks.
[0040] Specifically, the locking state of the electronic phase-locked loop (PLL) is determined by monitoring the amplitude and fluctuation range of the second error signal. When the electronic PLL is operating, if the second error signal output by the optical microwave PLL enters its linear operating region, it indicates that the phase of the laser to be locked has been modulated within the controllable range of the optical microwave PLL, at which point the electronic PLL is determined to be in a locked state. Subsequently, to further improve the PLL accuracy, the controller switches to the second PLL loop.
[0041] In a preferred embodiment of the present invention, the sensitivity of the optical phase-locked structure is higher than that of the optical microwave phase-locked structure, and the linear region of the optical phase-locked structure is narrower than that of the optical microwave phase-locked structure.
[0042] Specifically, optical phase-locked loops (PLLs) have high sensitivity, optical microwave PLLs have medium sensitivity, and electronic PLLs have low sensitivity. Optical PLLs have a narrower linear region, while optical microwave PLLs have a wider linear region.
[0043] In a preferred embodiment of the present invention, the optical phase-locked structure employs a balanced optical cross-correlation device, and the optical microwave phase-locked structure employs a balanced optical microwave phase detector.
[0044] Specifically, the optical phase-locked structure can also employ other optical phase-locked structures with equivalent functions. Similarly, the optical microwave phase-locked structure can also employ other optical microwave phase-locked structures with equivalent functions.
[0045] In a preferred embodiment of the present invention, the balanced optical cross-correlator is a monochromatic balanced optical cross-correlator or a dual-color balanced optical cross-correlator.
[0046] Specifically, the balanced optical crosscorrelator can be a two-color balanced optical crosscorrelator or a single-color balanced optical crosscorrelator.
[0047] In a preferred embodiment of the present invention, the electronic phase-locked loop structure includes: A photodetector, the input port of which is connected to the laser to be locked; The frequency and phase detector has its input ports connected to the radio frequency reference source and the output port of the photodetector, respectively.
[0048] Specifically, the photodetector is connected to both the frequency and phase detector and the laser to be locked. The locked laser signal emitted by the laser to be locked is converted into a microwave signal by the photodetector and then transmitted to the frequency and phase detector. An RF reference source is connected to the frequency and phase detector, and the RF reference signal emitted by the RF reference source is transmitted to the frequency and phase detector. The frequency and phase detector derives a third error signal based on the RF reference signal and the microwave signal. The frequency and phase detector is connected to the controller, and it sends the third error signal to the controller.
[0049] In a preferred embodiment of the present invention, the actuator includes: Piezoelectric ceramics are configured to adjust the phase or cavity length of the laser to be locked with high bandwidth and short stroke to compensate for high-frequency phase disturbances or short-term drift. An adjusting motor or thermal mechanism is configured to adjust the phase or cavity length of the laser to be locked with a low bandwidth and a large stroke to compensate for low-frequency phase disturbances or long-term drift.
[0050] Specifically, high-speed piezoelectric ceramics can be used, which feature short stroke and high bandwidth, making them suitable for rapid drift compensation. The bias of the piezoelectric ceramic is used as the bias of the actuator. The regulating motor and thermally-induced mechanism feature long stroke and low bandwidth, making them suitable for long-term drift compensation. The piezoelectric ceramic, regulating motor, and thermally-induced mechanism are all connected to the controller, which controls each of them.
[0051] Based on the laser phase-locked loop adaptive switching laser phase-locked device described in any of the above embodiments, the present invention also provides a preferred embodiment of the laser phase-locking method of the laser phase-locked loop adaptive switching laser phase-locked device.
[0052] Compared with existing phase-locked loop systems that use only a single phase detector or a simple "dual phase detector" structure, this invention has the following outstanding advantages: (1) A true “multi-phase-locked loop” structure The high-sensitivity BOC / TCBOC and the wide-linearity BOMPD each constitute two main phase-locked loops that can operate independently in closed loop (i.e., the first and second phase-locked loops serve as the main phase-locked loops), rather than simply being a superposition of two phase detector signals. The electronic phase detector loop (i.e., the third phase-locked loop) serves as an auxiliary loop for pre-locking and re-locking. The three components have a clear division of labor and mutual takeover through control logic.
[0053] (2) Achieving both accuracy and robustness When the environment is stable, the closed loop is dominated by BOC / TCBOC, and the system jitter can be compressed to <10fs. When the interference increases, it automatically switches to the BOMPD loop, utilizing its wide linear range and strong anti-interference capability to maintain lock-on that is not easily interrupted. In extreme cases, it can still recapture through the electronic pre-locking loop. Accuracy and stability are no longer mutually exclusive.
[0054] (3) Adaptive switching and automatic recovery This invention comprehensively judges the phase-locked loop (PLL) status by monitoring the amplitude and rate of change of the error signal and the actuator bias, and sets hysteresis and dwell time to avoid frequent mode switching. At different stages of interference occurrence and disappearance, the system can automatically switch between a high-sensitivity PLL and a wide-linearity PLL, and automatically revert to the high-precision mode when conditions are met, without manual intervention.
[0055] (4) The project is highly feasible The innovation of this invention is mainly focused on the system structure design and control strategy, which facilitates integration and upgrading on existing laser synchronization platforms and has strong engineering application value and promotion prospects.
[0056] like Figure 2 As shown in the figure, the laser phase-locked method of the laser phase-locked device with adaptive switching of multiple phase-locked loops according to an embodiment of the present invention includes the following steps: Step S100: After the laser phase-locked device is powered on or lost, the electronic phase-locked structure is locked based on the electronic phase-locked structure. Step S200: Based on the phase-locked state of the electronic phase-locked structure, the phase-locked state of the optical phase-locked structure, or the phase-locked state of the optical microwave phase-locked structure, the feedback source of the actuator is switched by the controller.
[0057] Specifically, when the laser phase-locked loop (PLL) is powered on or in a unlocked state, a third PLL is first used to lock the electronic PLL structure, i.e., pre-locking or re-locking. When the optical microwave PLL structure outputs the second error signal normally, the electronic PLL structure is in a locked state. During normal operation, the corresponding PLL is switched according to the phase-locking state of each PLL structure.
[0058] Step S100 specifically includes: Step S110: After the electronic phase-locked structure is locked, the controller uses the optical microwave phase-locked structure as a feedback source to control the actuator.
[0059] Specifically, once the electronic phase-locked loop is in the locked state, the first phase-locked loop is used to enter normal operation.
[0060] Step S110 specifically includes: Step S111: When the optical microwave phase-locked structure receives the second error signal, the electronic phase-locked structure locks.
[0061] Specifically, if the optical microwave phase-locked loop can output the second error signal normally, it indicates that all phase-locked loops are in working condition. If the electronic phase-locked loop is in a locked state, it is necessary to switch to the second phase-locked loop.
[0062] Step S200 specifically includes: Step S210: When the optical phase-locked structure is lost or about to lose lock, the controller uses the optical microwave phase-locked structure as a feedback source to control the actuator. Step S220: When the optical microwave phase-locked structure loses its lock, the controller uses the electronic phase-locked structure as a feedback source to control the actuator. Step S230: After the optical microwave phase-locked structure is locked, the controller uses the optical phase-locked structure as a feedback source to control the actuator. Step S240: After the electronic phase-locked structure is locked, the controller uses the optical microwave phase-locked structure as a feedback source to control the actuator.
[0063] Specifically, when the optical phase-locked loop (PLL) is lost or about to lose lock, a second PLL is used, with the optical microwave PLL as the feedback source. When the optical microwave PLL loses lock, a third PLL is used, with the electronic PLL as the feedback source. When either the electronic PLL or the optical microwave PLL is locked, the first PLL is used, with the optical PLL as the feedback source.
[0064] Step S210 specifically includes: Step S211: Obtain a first error signal based on the reference laser of the optical reference source and the locked laser of the laser to be locked; Step S212: When the first error signal is outside the first linear region or the bias of the actuator is at the travel boundary, the optical phase-locked structure loses lock. Step S213: When the first error signal is located in the first linear region and the rate of change is abnormal, the optical phase-locked structure is about to lose lock.
[0065] Specifically, when using the first phase-locked loop (PLL), if the first error signal is outside the first linear region, the optical PLL is in a unlocked state, and a switch to the second PLL is required. If the actuator bias is at the travel boundary, the optical PLL is in a unlocked state, and a switch to the second PLL is required. If the first error signal is within the first linear region and its rate of change is abnormal, the optical PLL is about to lose lock, and a switch to the second PLL is required.
[0066] Step S220 specifically includes: Step S221: Obtain a second error signal based on the radio frequency reference signal of the radio frequency reference source and the locked laser of the laser to be locked; Step S222: When the second error signal is outside the second linear region, the optical microwave phase-locked structure loses its lock.
[0067] Specifically, when using the second phase-locked loop, the second error signal is located outside the second linear region, and the optical microwave phase-locked structure is in a lost-lock state, so it is necessary to switch to the third phase-locked loop.
[0068] Step S230 specifically includes: Step S231: When the first error signal is maintained in the first linear region for a preset time, and the bias of the actuator is located in the range far from the travel boundary, the optical phase-locked structure is locked.
[0069] Specifically, when using the second phase-locked loop, the first error signal is located in the first linear region and is maintained for a preset time, and the actuator bias is located in the region far from the travel boundary, indicating that the error of the first error signal is small, the optical microwave phase-locked structure is in a locked state, and then it can be switched to the first phase-locked loop.
[0070] Step S240 specifically includes: Step S241: When the optical microwave phase-locked structure receives the second error signal, the electronic phase-locked structure is locked.
[0071] Specifically, if the optical microwave phase-locked loop can output the second error signal normally, it indicates that all phase-locked loops are in working condition. If the electronic phase-locked loop is in a locked state, it is necessary to switch to the second phase-locked loop.
[0072] Based on the laser phase-locked method of the laser phase-locked device with adaptive switching of multiple phase-locked loops described in any of the above embodiments, the present invention also provides an embodiment of a computer device.
[0073] The computer device of the present invention includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the laser phase-locked loop method as described in any of the above embodiments.
[0074] Based on the laser phase-locked method of the laser phase-locked device with adaptive switching of multiple phase-locked loops described in any of the above embodiments, the present invention also provides an embodiment of a computer-readable storage medium.
[0075] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the laser phase-locked loop method as described in any of the above embodiments.
[0076] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A laser phase-locked loop device with adaptive switching across multiple phase-locked loops, characterized in that, include: An optical reference source, a radio frequency reference source, and a laser to be locked, wherein the optical reference source and the radio frequency reference source are in a synchronized state; An optical phase-locked structure, wherein the input ports of the optical phase-locked structure are respectively connected to the optical reference source and the laser to be locked; An optical microwave phase-locked structure, wherein the input ports of the optical microwave phase-locked structure are respectively connected to the radio frequency reference source and the laser to be locked; An electronic phase-locked loop (PLL) structure, wherein the input ports of the electronic PLL structure are respectively connected to the radio frequency reference source and the laser to be locked; The controller is connected to the output ports of the optical phase-locked structure, the optical microwave phase-locked structure, the electronic phase-locked structure, and the laser to be locked. The actuator is connected to the controller; The controller adaptively switches the feedback source of the actuator based on the phase-locked state of the electronic phase-locked structure, the phase-locked state of the optical phase-locked structure, or the phase-locked state of the optical microwave phase-locked structure.
2. The laser phase-locked loop adaptive switching device according to claim 1, characterized in that, The sensitivity of the optical phase-locked structure is higher than that of the optical microwave phase-locked structure, and the linear region of the optical phase-locked structure is narrower than that of the optical microwave phase-locked structure.
3. The laser phase-locked loop adaptive switching device according to claim 2, characterized in that, The optical phase-locked structure employs a balanced optical cross-correlator, and the optical microwave phase-locked structure employs a balanced optical microwave phase detector.
4. The laser phase-locked loop adaptive switching device according to claim 3, characterized in that, The balanced optical cross-correlator is either a monochromatic balanced optical cross-correlator or a bichromatic balanced optical cross-correlator.
5. The laser phase-locked loop adaptive switching device according to claim 1, characterized in that, The electronic phase-locked loop structure includes: A photodetector, the input port of which is connected to the laser to be locked; The frequency and phase detector has its input ports connected to the radio frequency reference source and the output port of the photodetector, respectively.
6. The laser phase-locked loop adaptive switching device according to any one of claims 1 to 5, characterized in that, When the optical phase-locked structure reaches the critical state of loop loss, the controller uses the optical microwave phase-locked structure as a feedback source to control the actuator. When the optical microwave phase-locked structure loses its lock, the controller uses the electronic phase-locked structure as a feedback source to control the actuator. Once the optical microwave phase-locked structure is locked, the controller uses the optical phase-locked structure as a feedback source to control the actuator. Once the electronic phase-locked loop structure is locked, the controller uses the optical microwave phase-locked loop structure as a feedback source to control the actuator.
7. The laser phase-locked loop adaptive switching device according to any one of claims 1 to 5, characterized in that, The actuator includes: Piezoelectric ceramics are configured to adjust the phase or cavity length of the laser to be locked with high bandwidth and short stroke to compensate for high-frequency phase disturbances or short-term drift. An adjusting motor or thermal mechanism is configured to adjust the phase or cavity length of the laser to be locked with a low bandwidth and a large stroke to compensate for low-frequency phase disturbances or long-term drift.
8. A laser phase-locked loop (PLL) method for a laser PLL device with adaptive switching of multiple PLLs as described in any one of claims 1 to 7, characterized in that, Including the following steps: After the laser phase-locked loop device is powered on or loses its lock, it locks the electronic phase-locked loop structure based on the electronic phase-locked loop structure. Based on the phase-locked state of the electronic phase-locked structure, the phase-locked state of the optical phase-locked structure, or the phase-locked state of the optical microwave phase-locked structure, the controller switches the feedback source of the actuator.
9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the laser phase-locked loop method of claim 8.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the laser phase-locked loop method of claim 8.