Time-frequency transfer system, filtering method and related devices

Abstract

This application provides a time-frequency transfer system, a filtering method, and related equipment. The time-frequency transfer system includes at least a laser, a modulator, a signal source, a multi-stage repeater amplifier, a Fabry-Perot cavity filter, an optical fiber coupler, an optical power meter, a photodetector, a receiver, a radio frequency power meter, a processor, and a regulator. The optical signal output from the Fabry-Perot cavity filter is input to the optical power meter, the photodetector, and the receiver via the optical fiber coupler. The processor receives optical power data and radio frequency power data, and calculates first feedback data and second feedback data. The wavelength of the laser is adjusted using the first feedback data, and the cavity length of the Fabry-Perot cavity filter is adjusted using the second feedback data, so that the transmission peak of the Fabry-Perot cavity filter can coincide with the optical carrier and the two modulation sidebands, thereby accurately filtering out the ASE noise generated by the time-frequency transfer system.

Description

Technical Field

[0001] This application relates to the field of laser communication technology, and in particular to a time-frequency transmission system, filtering method and related equipment. Background Technology

[0002] In the mid-20th century, with the emergence and development of modern high-precision atomic clocks, people's understanding of time shifted from the era of astronomical observation to the era of precise measurement of atomic time. Fiber optic transmission, with its inherent characteristics of low loss, low noise, and strong anti-interference capability, became the ideal choice for high-precision time and frequency transmission. Typically, short-distance fiber optic time and frequency transmission can achieve high performance without the addition of compensation devices. However, for long-distance fiber optic time and frequency transmission, several repeaters need to be added to the transmission link to compensate for fiber loss. When the optical signal is amplified by the repeaters, noise is inevitably introduced, the most significant of which is amplified spontaneous emission (ASE) noise. To improve the quality of the received signal, a Fabry-Perot cavity filter is usually added at the receiving end to filter out the amplified ASE noise accumulated by the repeaters. However, the filter center of the Fabry-Perot cavity filter is easily affected by environmental factors and vibrations, which can drift, severely affecting the filtering effect and resulting in inaccurate filtering of ASE noise. Summary of the Invention

[0003] In view of this, the purpose of this application is to propose a time-frequency transmission system, filtering method and related equipment to solve the problem of inaccurate filtering of ASE noise during time-frequency transmission.

[0004] To achieve the above objectives, the first aspect of this application provides a time-frequency transfer system, comprising at least:

[0005] Laser;

[0006] The modulator has its input terminal connected to the output terminal of the laser.

[0007] The signal source has its output connected to the input of the modulator.

[0008] A multi-stage repeater amplifier, the input of which is connected to the output of the modulator;

[0009] The input terminal of the Fabry-Perot cavity filter is connected to the output terminal of the multi-stage repeater amplifier;

[0010] An optical fiber coupler, the input end of which is connected to the output end of the Fabry-Perot cavity filter;

[0011] An optical power meter, the input end of which is connected to the output end of the optical fiber coupler;

[0012] The input end of the photodetector is connected to the output end of the fiber optic coupler.

[0013] The receiver's input is connected to the output of the fiber optic coupler;

[0014] The input terminal of the radio frequency power meter is connected to the output terminal of the photodetector.

[0015] The processor's input terminals are connected to the output terminals of the optical power meter and the radio frequency power meter, respectively.

[0016] The regulator has its input terminal connected to the output terminal of the processor, and its output terminal connected to the input terminal of the laser and the input terminal of the Fabry-Perot cavity filter, respectively.

[0017] Optionally, the laser is a fiber laser, and the modulator is a digital-to-analog converter.

[0018] A second aspect of this application provides a filtering method applied to the time-frequency transfer system described in the first aspect, the method comprising:

[0019] The current optical power data and the current radio frequency power data are obtained from the optical power meter and the radio frequency power meter, respectively.

[0020] In response to the current optical power data not being within a first preset range and / or the current radio frequency power data not being within a second preset range, a first feedback data is determined based on the current optical power data, and a second feedback data is determined based on the current radio frequency power data;

[0021] The wavelength of the laser is adjusted based on the first feedback data to obtain updated optical power data, and the cavity length of the Fabry-Perot cavity filter is adjusted based on the second feedback data to obtain updated radio frequency power data.

[0022] This continues until the updated optical power data falls within a first preset range and the updated radio frequency power data falls within a second preset range.

[0023] Optionally, determining the first feedback data based on the optical power data includes:

[0024] The first feedback data F1 is calculated using the following formula.

[0025] F1 = (P - P0) * α1,

[0026] Where P represents the current optical power, P0 represents the target optical power, and α1 represents the first coefficient.

[0027] Optionally, determining the second feedback data based on the radio frequency power data includes:

[0028] The second feedback data F2 is calculated using the following formula.

[0029] F2 = (W - W0) * α2,

[0030] Where W represents the current RF power, W0 represents the target RF power, and α2 represents the second coefficient.

[0031] Optionally, adjusting the wavelength of the laser based on the first feedback data includes:

[0032] Based on the first feedback data, a first preset adjustment value is determined, and based on the first preset adjustment value, the wavelength of the laser is adjusted by the regulator.

[0033] Optionally, the cavity length of the Fabry-Perot cavity filter is adjusted based on the second feedback data.

[0034] Based on the second feedback data, a second preset adjustment value is determined, and based on the second preset adjustment value, the cavity length of the Fabry-Perot cavity filter is adjusted by the regulator.

[0035] A third aspect of this application also provides an apparatus for filtering the system described in the first aspect, comprising:

[0036] The acquisition module is configured to acquire current optical power data and current radio frequency power data from the optical power meter and the radio frequency power meter, respectively.

[0037] The determination module is configured to determine first feedback data based on the current optical power data and second feedback data based on the current radio frequency power data in response to the current optical power data not being within a first preset range and / or the current radio frequency power data not being within a second preset range;

[0038] The adjustment module is configured to adjust the wavelength of the laser based on the first feedback data to obtain updated optical power data, and to adjust the cavity length of the Fabry-Perot cavity filter based on the second feedback data to obtain updated radio frequency power data.

[0039] This continues until the updated optical power data falls within a first preset range and the updated radio frequency power data falls within a second preset range.

[0040] This application also provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor, when executing the computer program, implements the method as described in the second aspect.

[0041] This application also provides a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method as described in the second aspect.

[0042] As can be seen from the above description, the time-frequency transfer system, filtering method, and related equipment provided in this application include at least a laser, a modulator, a signal source, a multi-stage repeater amplifier, a Fabry-Perot cavity filter, an optical fiber coupler, an optical power meter, a photodetector, a receiver, a radio frequency power meter, a processor, and a regulator. The optical signal output from the Fabry-Perot cavity filter is input to the optical power meter, photodetector, and receiver via the optical fiber coupler. The processor receives the optical power data generated by the optical power meter and the radio frequency power data generated by the radio frequency power meter, and calculates the first feedback data and the second feedback data. The wavelength of the laser is adjusted using the first feedback data, and the cavity length of the Fabry-Perot cavity filter is adjusted using the second feedback data. This allows the transmission peak of the Fabry-Perot cavity filter to coincide with the optical carrier and the two modulation sidebands, thereby accurately filtering out the ASE noise generated by the time-frequency transfer system and improving the filtering effect. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the time-frequency transfer system according to an embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the structure of a time-frequency transfer system according to another embodiment of this application;

[0046] Figure 3 This is a flowchart illustrating a method for filtering a time-frequency transfer system according to an embodiment of this application.

[0047] Figure 4 This is a schematic diagram of the fast loop control thread in an embodiment of this application;

[0048] Figure 5 This is a schematic diagram of the slow loop control thread in an embodiment of this application;

[0049] Figure 6 This is a schematic diagram of the structure of a device for filtering a time-frequency transfer system according to an embodiment of this application;

[0050] Figure 7This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of this application. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0052] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0053] As described in the background section, optical fiber transmission, with its inherent characteristics of low loss, low noise, and strong anti-interference capability, has become the ideal choice for high-precision time and frequency transmission. Typically, short-distance optical fiber time and frequency transmission can achieve high performance without the need for compensation devices. However, for longer distances, several repeaters are required in the transmission link to compensate for fiber loss. When the optical signal is amplified by repeaters, noise is inevitably introduced, the most significant of which is amplified spontaneous emission (ASE) noise. The longer the optical fiber transmission distance, the more repeaters are needed, and the more amplified ASE noise accumulates in the optical signal, ultimately leading to a deterioration in the quality of the time and frequency signal.

[0054] To improve the quality of the received signal, filtering devices are typically added at the receiving end to filter out the amplified spontaneous emission noise accumulated by the repeater equipment, such as Waveshaper and DWDM filters. These filters have large bandwidths and cannot effectively filter out ASE noise. Waveshaper filters have a bandwidth of 25 GHz, and DWDM filters have a bandwidth of 100 GHz, while the modulation signal frequency is typically only 2.4 GHz. The large bandwidth of these filters cannot accurately filter out ASE noise. Fabry-Perot (FP) cavity tunable filters are a basic optical element. Essentially, they are bandpass filters, meaning they only allow signals of specific wavelengths to pass through, while other wavelengths are reflected or absorbed. They offer advantages such as fast tuning speed, high accuracy, and wide range. However, the filter center of an FP cavity is susceptible to drift due to environmental factors and vibrations.

[0055] During the filtering process, due to laser wavelength drift and Fabry-Perot cavity transmission peak drift, the three transmission peaks of the Fabry-Perot cavity cannot be perfectly aligned with the optical carrier and the two modulation sidebands, thus failing to accurately filter out ASE noise. The sideband refers to a frequency band generated above and below the center carrier frequency after modulation; its bandwidth is determined by the bandwidth of the modulation signal and the modulation method used.

[0056] In view of this, this application proposes a time-frequency transfer system and a method for filtering the time-frequency transfer system. This method can simultaneously adjust the filter center of the Fabry-Perot cavity and the wavelength of the laser to achieve precise filtering of the carrier and two sidebands through the transmission peak of the Fabry-Perot cavity filter. It should be noted that the Fabry-Perot cavity used in the embodiments of this application has high precision, with a filtering bandwidth of 7.5 MHz. Combined with the filtering method provided in this application, the optical carrier and two modulation sidebands can be accurately filtered out by using the transmission peak of the Fabry-Perot cavity, thereby effectively filtering out ASE noise.

[0057] The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0058] This application proposes a time-frequency transfer system, referring to... Figure 1 , Figure 1 A schematic diagram of a time-frequency transfer system is shown. The time-frequency transfer system 100 includes at least:

[0059] Laser 101;

[0060] Modulator 102, the input terminal of which is connected to the output terminal of laser 101;

[0061] The output terminal of the signal source 103 is connected to the input terminal of the modulator 102;

[0062] The multi-stage repeater amplifier 104 has its input terminal connected to the output terminal of the modulator.

[0063] The input terminal of the Fabry-Perot cavity filter 105 is connected to the output terminal of the multi-stage repeater amplifier 104;

[0064] The input end of the fiber optic coupler 106 is connected to the output end of the Fabry-Perot cavity filter 105.

[0065] The input terminal of the optical power meter 107 is connected to the output terminal of the optical fiber coupler 106.

[0066] The input end of the photodetector 108 is connected to the output end of the fiber optic coupler 106;

[0067] Receiver 109, the input end of which is connected to the output end of the fiber optic coupler 106;

[0068] The input terminal of the radio frequency power meter 110 is connected to the output terminal of the photodetector 108;

[0069] The processor 111 has its input terminals connected to the output terminals of the optical power meter 107 and the radio frequency power meter 110, respectively.

[0070] The regulator 112 has its input terminal connected to the output terminal of the processor 111, and its output terminal connected to the input terminal of the laser 101 and the input terminal of the Fabry-Perot cavity filter 105, respectively.

[0071] Specifically, modulator 102 modulates the laser emitted by laser 101 and the time-frequency signal emitted by signal source 103. The laser emitted by laser 101 serves as the optical carrier, which is modulated with a specific frequency signal. The modulated signal is displayed in the frequency domain as an optical carrier with two sidebands. The waveform of the time-frequency signal is transmitted via the optical carrier. For example, signal source 103 can be a microwave source that emits a stable sine wave. The modulated optical carrier enters a multi-stage repeater amplifier 104 for transmission. The multi-stage repeater amplifier 104 includes multiple repeater amplifiers. For example, in this embodiment, the repeater amplifier is an erbium-doped fiber amplifier. After the signal is transmitted over a long distance through optical fiber, its power will be lost. When it enters the repeater amplifier, the signal power will be increased. However, with each repeater amplification, the signal will be superimposed with spontaneous emission noise amplified by the gain medium in the repeater. After passing through long-distance optical fiber and amplifiers multiple times, the superimposed noise will increase.

[0072] The output optical signal of the multi-stage repeater amplifier 104 enters the Fabry-Perot cavity filter 105 for filtering. To accurately filter out ASE noise and improve the signal-to-noise ratio, an optical power meter 107, a photodetector 108, an RF power meter 110, a processor 111, and a regulator 112 are added to the time-frequency transmission system to jointly adjust the wavelength of the laser 101 and the cavity length of the Fabry-Perot cavity filter 105. The optical signal output from the Fabry-Perot cavity 105 passes through the fiber optic coupler 106 and then enters the optical power meter 107, the photodetector 108, and the receiver 109, respectively. By adjusting the splitting ratio of the fiber optic coupler 106, most of the optical signal is transmitted to the receiver 109 to ensure normal use of the optical signal. A small amount of optical signal is transmitted to the optical power meter 107 and the photodetector 108 for feedback of the filtering effect of the system. For example, the splitting ratio can be 90:10, that is, 90% of the optical signal is transmitted to the receiver 109 and 10% of the optical signal is transmitted to the optical power meter 107 and the photodetector 108.

[0073] The filtering effect is best when the transmission peak of the Fabry-Perot cavity is aligned with both the optical carrier and the double sideband. First, the optical carrier needs to be aligned with the center of the transmission peak. The optical power data emitted by the optical power meter 107 reflects the wavelength of the laser emitted by the laser 101. The optical power is at its maximum when the optical carrier is aligned with the center of one transmission peak of the Fabry-Perot cavity; that is, the value of the optical power data output by the optical power meter 107 is the highest. If the optical carrier deviates significantly from the center of one transmission peak of the Fabry-Perot cavity, the optical power value is lower. Therefore, the degree of alignment between the optical carrier and the center of one transmission peak of the Fabry-Perot cavity can be reflected by the optical power data. Adjusting the wavelength of the laser 10 appropriately based on the changes in the optical power data can align the optical carrier with the center of one transmission peak of the Fabry-Perot cavity.

[0074] Secondly, the RF power data output by the RF power meter 110 reflects the cavity length of the Fabry-Perot cavity. Since the frequency difference between the transmission peaks of the FP cavity is the same, adjusting the cavity length of the FP cavity is actually adjusting the frequency difference between the transmission peaks of the FP cavity. One of the optical signals output through the fiber coupler 106 enters the photodetector 108 for beat frequency, and the beat RF signal enters the RF power meter 110 to detect the RF power. The photodetector 108 can recover the frequency signal modulated onto the light. For example, light modulated with a 2.4 GHz signal is input to the photodetector 108, and the photodetector 108 outputs a 2.4 GHz RF signal. If the optical carrier is always aligned with the center of one transmission peak of the FP cavity, the beat RF power reaches its maximum when the frequency difference between the transmission peaks is equal to the frequency of the modulated signal, that is, the value of the RF power data output by the RF power meter 110 is the maximum. When the frequency difference between the transmission peaks is not equal to the frequency of the modulation signal, the larger the difference, the smaller the output RF power. In other words, the smaller the value of the RF power data output by the RF power meter 110, the RF power data can reflect the magnitude of the difference between the frequency difference between the transmission peaks and the frequency of the modulation signal.

[0075] In summary, after receiving optical power data and radio frequency power data, the processor 111 determines the corresponding adjustment value by calculating the feedback quantity. Based on the adjustment value, the regulator 112 adjusts the wavelength of the laser 101 and the cavity length of the FP cavity so that the transmission peak of the FP cavity can be aligned with the optical carrier and the double sideband simultaneously, thereby improving the filtering effect of the FP cavity filter.

[0076] Based on the time-frequency transmission system provided in this embodiment, the processor can receive optical power data and radio frequency power data in a timely manner, calculate the feedback quantity based on the optical power data and radio frequency power data, and adjust the wavelength of the laser and the cavity length of the FP cavity filter through the regulator. This achieves complete alignment between the FP cavity transmission layer and the optical carrier and double sideband, improves the filtering effect of the FP cavity filter, accurately filters out ASE noise generated by long-link transmission through multiple repeater amplifiers, and improves the signal-to-noise ratio. It should be noted that during the transmission of time-frequency signals by the time-frequency transmission system, the processor 111 can continuously acquire optical power data and radio frequency power data, and continuously adjust the wavelength of the laser 101 and the cavity length of the FP cavity through the regulator 112. The entire adjustment process is cyclical to ensure that the receiver 109 can continuously receive time-frequency signals with a high signal-to-noise ratio.

[0077] In some embodiments, the fiber optic coupler 106 may include a first fiber optic coupler 1061 and a second fiber optic coupler 1062. The first fiber optic coupler 1061 and the second fiber optic coupler 1062 can split the input optical signal into two optical signals according to a certain splitting ratio. Figure 2 A schematic diagram of a time-frequency transfer system according to another embodiment of this application is shown. The optical signal output from the Fabry-Perot cavity 105 enters fiber coupler 1061 via a first path, fiber coupler 1062 via a second path, and receiver 109 via a third path. The output optical signal from the first fiber coupler 1061 enters optical power meter 107, and the output optical signal from the second fiber coupler 1062 enters photodetector 108. Other connection methods of the time-frequency transfer system in this embodiment are the same as in the aforementioned embodiments, and the resulting effects are also the same; therefore, they will not be repeated here.

[0078] In some embodiments, the laser is a fiber laser, and the regulator is a digital-to-analog converter (DAC). In this embodiment, the fiber laser is a tunable fiber laser with internal piezoelectric ceramics. By adjusting the length of the piezoelectric ceramics, the wavelength of the laser can be adjusted accordingly. Simultaneously, piezoelectric ceramics are also disposed within the FP cavity. By adjusting the length of the piezoelectric ceramics, the cavity length of the FP cavity can be adjusted accordingly, that is, the frequency difference between the transmission peaks of the FP cavity can be adjusted. In this embodiment, the regulator is a DAC. The DAC can apply voltage to the laser and the piezoelectric ceramics inside the FP cavity to change the length of the piezoelectric ceramics, thereby achieving the purpose of adjusting the wavelength and cavity length. In other embodiments, the laser in the time-frequency transfer system can also be other types of lasers, such as DFB semiconductor lasers. By adjusting the current of the DFB semiconductor laser, its wavelength can be adjusted. Therefore, when using different lasers, it is necessary to select a regulator capable of adjusting the wavelength. The types of lasers and regulators can be selected according to actual needs, which will not be elaborated further here.

[0079] Corresponding to the aforementioned time-frequency transfer system, this application also provides a filtering method applied to the aforementioned time-frequency transfer system, referencing... Figure 3 The method includes the following steps:

[0080] Step 302: Obtain current optical power data and current radio frequency power data from the optical power meter and the radio frequency power meter, respectively. The processor obtains the current optical power data from the optical power meter and the current radio frequency power data from the radio frequency power meter, and performs calculations based on the current optical power data and the current radio frequency power data.

[0081] Step 304: In response to the current optical power data not being within a first preset range and / or the current radio frequency power data not being within a second preset range, determine first feedback data based on the current optical power data, and determine second feedback data based on the current radio frequency power data.

[0082] First, it is necessary to determine whether the current optical power data is within a first preset range and whether the current radio frequency (RF) power data is within a second preset range. If either of these data is outside the preset range, feedback data is calculated. In this embodiment, the processor acquires the optical power data and RF power data in real time. If the current optical power data and the current RF power data are close to the target optical power or the target RF power, that is, if the current optical power is within the first preset range including the target optical power and the current RF power is within the second preset range including the target RF power, then the current optical power data is considered equal to the target optical power and the current RF power data is considered equal to the target RF power. No adjustment of the laser wavelength or the Fabry-Perot cavity length is required. The first and second preset ranges can be set according to actual needs; no specific limitations are imposed in this embodiment.

[0083] As mentioned above, optical power data can provide feedback on the wavelength of the laser. The first feedback data F1 is calculated from the optical power data, and the specific calculation formula is as follows:

[0084] F1=(P-P0)*α1

[0085] Where P represents the current optical power data, P0 represents the target optical power, and α1 represents the first coefficient. P0 is set based on historical experience values ​​and is usually slightly larger than the historical maximum value output by the optical power meter. α1 is obtained through debugging experiments.

[0086] The RF power data reflects the cavity length of the FP cavity. The second feedback data F2 is calculated from the RF power data. The specific calculation formula is as follows:

[0087] F2=(W-W0)*α2

[0088] Where W represents the current RF power data, W0 represents the target RF power, and α2 represents the second coefficient. W0 is set based on historical experience values ​​and is usually slightly larger than the historical maximum value output by the RF power meter. α2 is obtained through debugging and testing.

[0089] Step 306: Adjust the wavelength of the laser according to the first feedback data to obtain updated optical power data; and adjust the cavity length of the Fabry-Perot cavity filter according to the second feedback data to obtain updated radio frequency power data.

[0090] This continues until the updated optical power data falls within a first preset range and the updated radio frequency power data falls within a second preset range.

[0091] In specific implementation, the wavelength of the laser is adjusted according to the first feedback data, specifically including: determining a first preset adjustment value associated with the first feedback data, and adjusting the wavelength of the laser through the regulator based on the first preset adjustment value. After calculating the first feedback data, the first preset adjustment value corresponding to the feedback data is determined and sent to the regulator, which then adjusts the wavelength of the laser. For example, when the laser is a tunable fiber laser with piezoelectric ceramic, the regulator is a digital-to-analog converter (DAC). The first feedback value represents the difference between the current optical power and the target optical power, i.e., the amount of optical power that needs to be increased. Based on the inherent properties of the laser, a corresponding first preset adjustment value is set for each first feedback point. The first preset adjustment value can be a specific numerical value. The processor converts the first preset adjustment value into a binary string, sends the binary string to the DAC, and the DAC converts the binary string into a voltage value. Based on this voltage value, a voltage is applied to the piezoelectric ceramic to change its length, thereby changing the wavelength of the fiber laser. When the wavelength of the laser changes, the optical signal continues to be transmitted through the time-frequency transmission system, and then the processor obtains the updated optical power data.

[0092] In specific implementation, the cavity length of the Fabry-Perot cavity filter is adjusted according to the second feedback data. This includes: determining a second preset adjustment value associated with the second feedback data; and adjusting the cavity length of the Fabry-Perot cavity filter using the regulator based on the second preset adjustment value. After calculating the second feedback data, a second preset adjustment value corresponding to the feedback data is determined and sent to the regulator, which then adjusts the cavity length of the Fabry-Perot cavity filter. For example, when piezoelectric ceramics are placed inside the Fabry-Perot cavity, the regulator is a digital-to-analog converter. The second feedback value represents the difference between the current RF power and the target RF power, i.e., the amount of RF power that needs to be increased. Based on the inherent properties of the Fabry-Perot cavity, a corresponding second preset adjustment value is provided for each second feedback point. The second preset adjustment value can be a specific numerical value. The processor converts the second preset adjustment value into a binary string, which is then sent to a digital-to-analog converter (DAC). The DAC converts the binary string into a voltage value, and pressure is applied to the piezoelectric ceramic based on this voltage value to change the length of the piezoelectric ceramic, thereby changing the cavity length of the Fabry-Perot cavity. After the cavity length of the Fabry-Perot cavity changes, the optical signal continues to propagate through the time-frequency transmission system, and the processor then obtains updated radio frequency power data.

[0093] In addition, refer to Figure 4The principle of calculating and adjusting the laser wavelength based on optical power data can also be described as follows: if the current optical power data increases, the voltage applied to the piezoelectric ceramic in the laser is increased; if the current optical power data does not increase, the voltage applied to the piezoelectric ceramic in the laser is decreased. This process is repeated until the optical power data falls within a first preset range. (Reference) Figure 5 The principle of calculating and adjusting the cavity length of the Fabry-Perot cavity based on radio frequency power data can also be described as follows: if the current radio frequency power data increases, the voltage applied to the piezoelectric ceramic in the Fabry-Perot cavity is increased; if the current radio frequency power data does not increase, the voltage applied to the piezoelectric ceramic in the Fabry-Perot cavity is decreased. This process is repeated until the radio frequency power data is within the second preset range.

[0094] Figure 4 The regulating thread can be called the fast-loop regulating thread. Figure 5 The adjustment thread in this process can be called the slow-loop control thread. This application employs a dual-threaded fast-slow-loop feedback algorithm. Since the light transmittance is maximum at the transmission peak of the FP cavity, stabilizing the optical power at the maximum point indicates that the laser frequency is aligned with the center of one transmission peak of the FP cavity. If increasing the voltage of the piezoelectric ceramic in the laser causes the optical power to rise, it indicates that the voltage adjustment direction is correct, and the voltage needs to be increased further. If the voltage continues to increase until the optical power decreases, it indicates that the laser wavelength tuning has exceeded the center of the transmission peak, leading to a decrease in transmittance and thus a decrease in optical power. Therefore, the voltage of the piezoelectric ceramic needs to be adjusted in the opposite direction. This process is repeated until the optical power fluctuates within a small range near its maximum value, i.e., the optical power data falls within the first preset range. Similarly, if increasing the voltage of the piezoelectric ceramic in the FP cavity causes the radio frequency (RF) power to rise, it indicates that the voltage adjustment direction is correct, and the voltage needs to be increased further. If the voltage continues to increase until the RF power decreases, it indicates that the frequency difference between the transmission peaks of the FP cavity exceeds the frequency of the modulation signal, leading to a decrease in RF power. Therefore, the voltage of the piezoelectric ceramic in the FP cavity needs to be adjusted in the opposite direction. This process is repeated until the RF power fluctuates within a small range near its maximum value, i.e., the RF power data falls within the second preset range. It should be noted that the fast-loop control speed can be set to approximately 15 times the slow-loop control speed to ensure that the laser wavelength can quickly stabilize at the center of the FP cavity transmission peak after each adjustment of the FP cavity length. Only then can the RF power read indicate whether the FP cavity transmission peak is aligned with the two sidebands. The fast-loop and slow-loop control speeds can be jointly controlled by the processor and the regulator.

[0095] It should be noted that the method in this embodiment can be executed by a single device, such as a computer or server. The method can also be applied in a distributed scenario, where multiple devices cooperate to complete the task. In such a distributed scenario, one of these devices may execute only one or more steps of the method in this embodiment, and the multiple devices will interact with each other to complete the method described.

[0096] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0097] This application also provides a filtering device for use in time-frequency transmission systems.

[0098] refer to Figure 6 The filtering device applied to the time-frequency transfer system includes:

[0099] The acquisition module 602 is configured to acquire current optical power data and current radio frequency power data from the optical power meter and the radio frequency power meter, respectively.

[0100] The determining module 604 is configured to determine first feedback data based on the current optical power data and second feedback data based on the current radio frequency power data in response to the current optical power data not being within a first preset range and / or the current radio frequency power data not being within a second preset range.

[0101] The adjustment module 606 is configured to adjust the wavelength of the laser based on the first feedback data to obtain updated optical power data, and to adjust the cavity length of the Fabry-Perot cavity filter based on the second feedback data to obtain updated radio frequency power data.

[0102] This continues until the updated optical power data falls within a first preset range and the updated radio frequency power data falls within a second preset range.

[0103] In some embodiments, the determining module 604 is further configured to calculate the first feedback data F1 using the following formula.

[0104] F1 = (P - P0) * α1,

[0105] Where P represents the current optical power data, P0 represents the target optical power, and α1 represents the first coefficient.

[0106] In some embodiments, the determining module 604 is further configured to calculate the second feedback data F2 using the following formula.

[0107] F2 = (W - W0) * α2,

[0108] Where W represents the current RF power data, W0 represents the target RF power, and α2 represents the second coefficient.

[0109] In some embodiments, the adjustment module 606 is further configured to determine a first preset adjustment value associated with the first feedback data, and adjust the wavelength of the laser by the regulator based on the first preset adjustment value.

[0110] In some embodiments, the adjustment module 606 is further configured to determine a second preset adjustment value associated with the second feedback data, and adjust the cavity length of the Fabry-Perot cavity filter through the regulator based on the second preset adjustment value.

[0111] For ease of description, the above devices are described in terms of function, divided into various modules. Of course, in implementing this application, the functions of each module can be implemented in one or more software and / or hardware.

[0112] The apparatus of the above embodiments is used to implement the corresponding filtering method applied to the time-frequency transfer system in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0113] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the filtering method for a time-frequency transfer system described in any of the above embodiments.

[0114] Figure 7 This embodiment illustrates a more specific hardware structure of an electronic device, which may include a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, memory 1020, input / output interface 1030, and communication interface 1040 are interconnected internally via the bus 1050.

[0115] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0116] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0117] The input / output interface 1030 is used to connect input / output modules to realize information input and output. Input / output modules can be configured as components within the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touchscreens, microphones, various sensors, etc., while output devices may include displays, speakers, vibrators, indicator lights, etc.

[0118] The communication interface 1040 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0119] Bus 1050 includes a pathway for transmitting information between various components of the device, such as processor 1010, memory 1020, input / output interface 1030, and communication interface 1040.

[0120] It should be noted that although the above-described device only shows the processor 1010, memory 1020, input / output interface 1030, communication interface 1040, and bus 1050, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0121] The electronic devices described above are used to implement the corresponding filtering methods applied to time-frequency transfer systems in any of the foregoing embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0122] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the filtering method applied to the time-frequency transfer system as described in any of the above embodiments.

[0123] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0124] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to execute the filtering method applied to the time-frequency transfer system as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0125] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0126] Additionally, to simplify the description and discussion, and to avoid obscuring the embodiments of this application, the well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Furthermore, the apparatus may be shown in block diagram form to avoid obscuring the embodiments of this application, and this also takes into account the fact that the details of the implementation of these block diagram apparatuses are highly dependent on the platform on which the embodiments of this application will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details (e.g., circuits) have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that the embodiments of this application can be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0127] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0128] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A time-frequency transfer system, characterized by, At least including: Laser; The modulator has its input terminal connected to the output terminal of the laser. The signal source has its output connected to the input of the modulator. A multi-stage repeater amplifier, the input of which is connected to the output of the modulator; The input terminal of the Fabry-Perot cavity filter is connected to the output terminal of the multi-stage repeater amplifier; An optical fiber coupler, the input end of which is connected to the output end of the Fabry-Perot cavity filter; An optical power meter, the input end of which is connected to the output end of the optical fiber coupler; The input end of the photodetector is connected to the output end of the fiber optic coupler. The receiver's input is connected to the output of the fiber optic coupler; The input terminal of the radio frequency power meter is connected to the output terminal of the photodetector. The processor's input terminals are connected to the output terminals of the optical power meter and the radio frequency power meter, respectively. The regulator has its input terminal connected to the output terminal of the processor, and its output terminal connected to both the input terminal of the laser and the input terminal of the Fabry-Perot cavity filter. After receiving optical power data and radio frequency power data, the processor determines the corresponding adjustment value by calculating the feedback value. Based on the adjustment value, the processor adjusts the wavelength of the laser and the cavity length of the Fabry-Perot cavity filter through the regulator so that the transmission peak of the Fabry-Perot cavity can be aligned with the optical carrier and the double sideband simultaneously, thereby improving the filtering effect of the Fabry-Perot cavity filter.

2. The system of claim 1, wherein, The laser is a fiber laser, and the regulator is a digital-to-analog converter.

3. A filtering method applied to the time-frequency transfer system according to claim 1 or claim 2, characterized in that, The method includes: The current optical power data and the current radio frequency power data are obtained from the optical power meter and the radio frequency power meter, respectively. In response to the current optical power data not being within a first preset range and / or the current radio frequency power data not being within a second preset range, a first feedback data is determined based on the current optical power data, and a second feedback data is determined based on the current radio frequency power data; The wavelength of the laser is adjusted based on the first feedback data to obtain updated optical power data, and the cavity length of the Fabry-Perot cavity filter is adjusted based on the second feedback data to obtain updated radio frequency power data. This continues until the updated optical power data falls within a first preset range and the updated radio frequency power data falls within a second preset range.

4. The method according to claim 3, characterized in that, The determination of the first feedback data based on the optical power data includes: The first feedback data is calculated by the following formula , ， wherein P denotes the current optical power data, denotes the target optical power, denotes the first coefficient.

5. The method of claim 3, wherein, The determination of the second feedback data based on the radio frequency power data includes: The second feedback data is calculated by the following formula , ， wherein, represents the current radio frequency power data, represents the target radio frequency power, represents the second coefficient.

6. The method of claim 3, wherein, The step of adjusting the wavelength of the laser based on the first feedback data includes: Based on the first feedback data, a first preset adjustment value is determined, and based on the first preset adjustment value, the wavelength of the laser is adjusted by the regulator.

7. The method according to claim 3, characterized in that, The cavity length of the Fabry-Perot cavity filter is adjusted based on the second feedback data. Based on the second feedback data, a second preset adjustment value is determined, and based on the second preset adjustment value, the cavity length of the Fabry-Perot cavity filter is adjusted by the regulator.

8. A filtering device applied to the time-frequency transfer system according to claim 1 or claim 2, characterized in that, include: The acquisition module is configured to acquire current optical power data and current radio frequency power data from the optical power meter and the radio frequency power meter, respectively. The determination module is configured to determine first feedback data based on the current optical power data and second feedback data based on the current radio frequency power data in response to the current optical power data not being within a first preset range and / or the current radio frequency power data not being within a second preset range; The adjustment module is configured to adjust the wavelength of the laser based on the first feedback data to obtain updated optical power data, and to adjust the cavity length of the Fabry-Perot cavity filter based on the second feedback data to obtain updated radio frequency power data. This continues until the updated optical power data falls within a first preset range and the updated radio frequency power data falls within a second preset range.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 3 to 7.

10. A non-transitory computer-readable storage medium storing computer instructions, wherein, The computer instructions are used to cause the computer to perform the method according to any one of claims 3 to 7.

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