Phase offset compensation method and related device

Abstract

Embodiments of the present application provide a phase offset compensation method and a related device. While using FDM to improve the sampling rate, an optical device reduces the bandwidth required by the optical device, and decreases the length of a signal sequence emitted by the optical device. The method comprises: an optical device sends a sounding frame to a medium, the sounding frame comprising N frequencies; the optical device sends a calibration frame to the medium, the calibration frame comprising W frequencies, and the W frequencies being equal to at least some frequencies among the N frequencies; the optical device receives a response frame from the medium, the response frame being a response frame returned by the medium to the optical device on the basis of the sounding frame; the optical device receives a calibration response frame from the medium, the calibration response frame being a response frame returned by the medium to the optical device on the basis of the calibration frame; and the optical device performs phase offset compensation on the response frame on the basis of the calibration response frame to obtain a compensated response frame.

Description

A method for compensating phase shift and related equipment

[0001] This application claims priority to Russian Patent Application No. RU2025105895, filed on March 13, 2025, entitled "A method for compensating phase shift and related apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical communication technology, and in particular to a phase offset compensation method and related equipment. Background Technology

[0003] Distributed fiber-optic acoustic sensors (DAS) are increasingly used in detection fields, such as oil and gas resource exploration, oil and gas pipeline inspection, and railway track inspection.

[0004] DAS (Digital Amplifier Sensor) can use optical fibers as sensors, with each segment of the fiber considered a detection point. Optical devices can improve the sampling rate of the detection through frequency division multiplexing (FDM). Specifically, within a detection cycle, the optical device sends detection light of multiple different frequencies to the fiber. The fiber returns echo light to the optical device based on the detection light, and the optical device performs detection based on the echo light. To suppress the phase shift between different frequencies in the echo light, the optical device simultaneously transmits a compensation frequency while sending each frequency to the fiber. The optical device can directly measure the phase shift between each frequency and the compensation frequency to compensate for the phase shift of each frequency in the echo light, thereby suppressing or overcoming the phase shift between different frequencies and improving detection accuracy.

[0005] However, because optical devices need to send a compensation frequency along with each frequency, the bandwidth required by the optical device is increased, as is the length of the signal sequence emitted by the optical device, which in turn increases the amount of storage space required by the optical device. Furthermore, the simultaneous transmission of the compensation frequency and the transmission of each frequency introduces noise and reduces detection accuracy. Summary of the Invention

[0006] This application provides a phase offset compensation method and related equipment. The optical device uses FDM to increase the sampling rate while reducing the bandwidth required by the optical device and reducing the length of the signal sequence emitted by the optical device.

[0007] In a first aspect, this application provides a phase offset compensation method, the method comprising: an optical device sending a probe frame to a medium, the probe frame including N frequencies, where N is any integer greater than 1; the optical device sending K calibration frames to the medium, where K is any integer greater than or equal to 1, the calibration frames including W frequencies, where W is any integer greater than or equal to 1 and less than or equal to N, and the W frequencies are equal to at least a portion of the N frequencies; the optical device receiving a response frame from the medium, the response frame being a response frame returned by the medium to the optical device based on the probe frame; the optical device receiving K calibration response frames from the medium, the K calibration response frames being response frames returned by the medium to the optical device based on the K calibration frames; and the optical device compensating for the phase offset of the response frames based on the K calibration response frames to obtain a compensated response frame.

[0008] As shown in this aspect, to improve the sampling rate, the probe frame sent by the optical device to the medium includes multiple frequencies. After the probe frame sent by the optical device to the medium, a calibration frame is sent. The calibration frame enables phase compensation for each frequency in the response frame. Since it is not necessary to send a compensation frequency while sending each frequency in the probe frame, but to achieve phase compensation by sending a calibration frame independently, the frequency used to achieve phase compensation will not occupy too much bandwidth of the optical device, reducing the length of the signal sequence sent by the optical device. While achieving phase compensation, the bandwidth required by the optical device is reduced, the introduced noise is reduced, and the detection accuracy is improved.

[0009] Based on the first aspect, in one optional implementation, the optical device compensates for the phase shift of the response frame according to the K calibration response frames to obtain the compensated response frame, including: the optical device obtaining the phase shift amount corresponding to each frequency in the response frame according to the K calibration response frames; the optical device compensating for the phase shift of the response frame according to the phase shift amount corresponding to each frequency in the response frame to obtain the compensated response frame.

[0010] Using this implementation, the optical device performs phase compensation through a calibration frame within a detection cycle, which effectively reduces the noise introduced during the phase compensation process and lowers the phase compensation error.

[0011] Based on the first aspect, in one optional implementation, W is equal to N, and the W frequencies are equal to the N frequencies respectively.

[0012] By adopting this implementation method, the frequencies included in the calibration frame are equal to the frequencies included in the detection frame, which effectively reduces the number of calibration frames included in the detection cycle and improves detection efficiency.

[0013] Based on the first aspect, in one optional implementation, the optical device compensates for the phase shift of the response frame according to the K calibration response frames to obtain a compensated response frame, including: the optical device obtaining a signal value corresponding to each frequency in the calibration response frame; the optical device obtaining a phase shift corresponding to a target frequency fi in the calibration response frame according to the signal value corresponding to each frequency in the calibration response frame, wherein the phase shift corresponding to the target frequency fi is the difference between the signal value corresponding to the target frequency fi and the signal value corresponding to the reference frequency fx, and the target frequency fi is any frequency different from the reference frequency fx among the W frequencies; the optical device obtaining a phase shift corresponding to a first frequency is the difference between the signal value corresponding to the first frequency and the phase shift corresponding to a second frequency, wherein the first frequency is one of the N frequencies in the response frame, the second frequency is one of the W frequencies in the calibration response frame, and the first frequency and the second frequency are equal.

[0014] In this implementation, after the optical device sends a probe frame to the medium, a calibration frame is sent. The phase offset corresponding to each frequency in the response frame can be obtained through the calibration frame. Based on the phase offset, phase compensation is performed on each frequency in the response frame, which reduces the bandwidth required by the optical device, reduces the introduced noise, and improves the detection accuracy.

[0015] Based on the first aspect, in an optional implementation, K is greater than 1, W is less than N, the intersection of any two calibration frames in the K calibration frames includes R1 frequencies, R1 is any integer greater than or equal to 1 and less than N, the R1 frequencies are equal to some frequencies among the N frequencies, and the union of the K calibration frames includes R2 frequencies, R2 is any integer greater than or equal to N, the N frequencies are equal to at least some frequencies among the R2 frequencies.

[0016] Using this implementation, a detection period includes multiple calibration frames. Therefore, the distribution of the frequencies used for calibration within that detection period is more dispersed, effectively reducing the noise introduced during phase compensation and lowering the error of phase compensation.

[0017] Based on the first aspect, in one optional implementation, the K calibration response frames include a first calibration response frame and a second calibration response frame. The optical device compensates for the phase shift of the response frames based on the K calibration response frames to obtain a compensated response frame. This includes: the optical device obtaining signal values ​​corresponding to each frequency in the first calibration response frame and the second calibration response frame; the optical device obtaining a phase shift amount corresponding to a first target frequency fi1 in the first calibration response frame based on the signal values ​​corresponding to each frequency in the first calibration response frame, wherein the phase shift amount corresponding to the first target frequency fi1 is the difference between the signal value corresponding to the first target frequency fi1 and the signal value corresponding to the reference frequency fx, and the first target frequency fi1 is any frequency in the first calibration response frame that is different from the reference frequency fx, and the first calibration response frame includes the reference frequency fx; the optical device then calculates the phase shift amount corresponding to each frequency in the second calibration response frame based on the signal values ​​corresponding to each frequency. The phase offset corresponding to the second target frequency fi2 in the second calibration response frame is obtained. The phase offset corresponding to the second target frequency fi2 is the sum of a first parameter and a second parameter. The first parameter is the difference between the signal value corresponding to the second target frequency fi2 and the signal value corresponding to the intersection frequency. The intersection frequency is one of the R1 frequencies. The second parameter is the difference between the signal value corresponding to the intersection frequency and the signal value corresponding to the reference frequency fx. The second target frequency fi2 is any frequency in the second calibration response frame that is different from the intersection frequency. The optical device obtains the phase offset corresponding to the third frequency as the difference between the signal value corresponding to the third frequency and the phase offset corresponding to the fourth frequency. The third frequency is any frequency in the first response frame and the second response frame. The fourth frequency is one of the first calibration response frame and the second calibration response frame, and the third frequency is equal to the fourth frequency.

[0018] In this implementation, after the optical device sends a probe frame to the medium, a calibration frame is sent. The phase offset corresponding to each frequency in the response frame can be obtained through the calibration frame. Based on the phase offset, phase compensation is performed on each frequency in the response frame, which reduces the bandwidth required by the optical device, reduces the introduced noise, and improves the detection accuracy.

[0019] Based on the first aspect, in one optional implementation, the time interval between two adjacent frequencies entering the medium among the W frequencies is less than the time interval between two adjacent frequencies entering the medium among the N frequencies.

[0020] By employing this implementation method, when the time interval between two adjacent frequencies entering the medium among the W frequencies is less than the time interval between two adjacent frequencies entering the medium among the N frequencies, the error of phase compensation is effectively reduced.

[0021] Based on the first aspect, in one optional implementation, the optical device sends M probe frames to the medium, where M is any integer greater than 1. In the M probe frames, the time interval between two adjacent probe frames with the same target frequency entering the medium is TX, where TX is greater than or equal to a preset value. In the probe frames, the time interval between two adjacent frequencies entering the medium is T = TX / N.

[0022] By employing this implementation method, when the time interval TX between two adjacent detection frames of the same target frequency entering the medium is greater than or equal to a preset value, interference or overlap between detection frames is effectively avoided, while maintaining a sufficient time interval between two adjacent detection frames to avoid interference and ensure the synchronization performance of the system.

[0023] Based on the first aspect, in one optional implementation, the time interval between the same target frequency entering the medium in adjacent calibration frames and detection frames is TX, where TX is greater than or equal to a preset value.

[0024] By adopting this implementation method, when the time interval TX between the same target frequency entering the medium in adjacent calibration frames and probe frames is greater than or equal to a preset value, it effectively avoids mutual interference or overlap between probe frames and calibration frames, while maintaining sufficient time intervals between each frequency in the calibration frame and each frequency in the probe frame to avoid interference and ensure the synchronization performance of the system.

[0025] Based on the first aspect, in one optional implementation, if the medium is an optical fiber, the preset value is 2Ln / c, where L is the length of the optical fiber connecting the detection point used to reflect the target frequency and the optical device, n is the effective refractive index of the optical fiber core, and c is the speed of light in a vacuum.

[0026] This implementation effectively avoids interference or overlap between frequencies, while maintaining sufficient time intervals between frequencies to prevent interference and ensure system synchronization performance.

[0027] Based on the first aspect, in an optional implementation, before the optical device sends a probe frame to the medium, the method further includes: the optical device windowing the frequencies included in the probe frame in the time domain and / or in the frequency domain.

[0028] By using this implementation method, the frequencies included in the detection frame are windowed to reduce crosstalk between frequencies, improve the quality of the signal at the end of the medium, and enhance the receiving performance and detection reliability of the optical device.

[0029] Based on the first aspect, in an optional implementation, before the optical device sends a calibration frame to the medium, the method further includes: the optical device windowing the frequencies included in the calibration frame in the time domain and / or in the frequency domain.

[0030] By using this implementation method, the frequencies included in the calibration frame are windowed to reduce crosstalk between frequencies, improve the quality of the signal at the end of the medium, and enhance the receiving performance and detection reliability of the optical equipment.

[0031] Based on the first aspect, in one optional implementation, the optical device sending a probe frame to the medium includes: the optical device sending the N frequencies included in the probe frame to the medium in a non-monotonic order.

[0032] Using this implementation, the order of the N frequencies included in the probe frame sent by the optical device to the medium can be non-monotonic to reduce crosstalk and nonlinear effects. The non-monotonic order of the N frequencies sent by the optical device to the medium can break the frequency correlation between adjacent signals, reduce the electromagnetic coupling strength between them, and thus reduce the occurrence of crosstalk.

[0033] Based on the first aspect, in one optional implementation, the optical device sending a calibration frame to the medium includes: the optical device sending the W frequencies included in the calibration frame to the medium in a non-monotonic order.

[0034] Using this implementation, the order of the W frequencies included in the calibration frame sent by the optical device to the medium can be non-monotonic to reduce crosstalk and nonlinear effects. The order of the W frequencies sent by the optical device to the medium can be non-monotonic to break the frequency correlation between adjacent signals, reduce the electromagnetic coupling strength between them, and thus reduce the occurrence of crosstalk.

[0035] Secondly, this application provides a compensation device, including a transmitting module, a processing module, and a receiving module. The transmitting module is used to transmit a probe frame to a medium, the probe frame including N frequencies, where N is any integer greater than 1; and to transmit K calibration frames to the medium, where K is any integer greater than or equal to 1. The calibration frames include W frequencies, where W is any integer greater than or equal to 1 and less than or equal to N, and the W frequencies are equal to at least a portion of the N frequencies. The receiving module is used to receive a response frame from the medium, the response frame being a response frame returned by the medium to the optical device based on the probe frame; and to receive K calibration response frames from the medium, the K calibration response frames being response frames returned by the medium to the optical device based on the K calibration frames. The processing module is used to compensate for the phase shift of the response frames based on the K calibration response frames to obtain a compensated response frame. For an explanation of the beneficial effects of this aspect, please refer to the first aspect, which will not be elaborated further.

[0036] Based on the second aspect, in one optional implementation, W is equal to N, and the W frequencies are equal to the N frequencies respectively.

[0037] Based on the second aspect, in an optional implementation, K is greater than 1, W is less than N, the intersection of any two calibration frames in the K calibration frames includes R1 frequencies, R1 is any integer greater than or equal to 1 and less than N, the R1 frequencies are equal to some frequencies among the N frequencies, and the union of the K calibration frames includes R2 frequencies, R2 is any integer greater than or equal to N, the N frequencies are equal to at least some frequencies among the R2 frequencies.

[0038] Thirdly, this application provides an optical device, including an optical transmitter, an optical receiver, and a processor; the optical transmitter is configured to send probe frames to a medium, the probe frames including N frequencies, where N is any integer greater than 1, and to send K calibration frames to the medium, where K is any integer greater than or equal to 1, the calibration frames including W frequencies, where W is any integer greater than or equal to 1 and less than or equal to N, and the W frequencies are equal to at least a portion of the N frequencies; the optical receiver is configured to receive response frames from the medium, the response frames being response frames returned by the medium to the optical device based on the probe frames, and to receive K calibration response frames from the medium, the K calibration response frames being response frames returned by the medium to the optical device based on the K calibration frames; the processor is configured to compensate for the phase shift of the response frames based on the K calibration response frames to obtain compensated response frames. For an explanation of the beneficial effects of this aspect, please refer to the first aspect, which will not be elaborated further.

[0039] Fourthly, this application provides a chip including at least one processing unit and an interface circuit, wherein the interface circuit is used to provide program instructions or data to the at least one processing unit, and the at least one processing unit is used to execute the program instructions to implement the method described in any of the first aspects above.

[0040] Fifthly, this application provides a computer-readable storage medium including instructions that, when executed by a processor, implement the method as described in any one of the first aspects above.

[0041] In a sixth aspect, this application provides a computer program product including instructions that, when executed on a processor, perform the method as described in any one of the first aspects above. Attached Figure Description

[0042] Figure 1 is a structural example diagram of the optical device provided in this application;

[0043] Figure 2 is a flowchart of the steps of the first embodiment of the phase offset compensation method provided in this application;

[0044] Figure 3 is an example diagram of a first embodiment of the optical device provided in this application transmitting optical signals to a medium;

[0045] Figure 4 is an example diagram of the phase shift shown in Figure 3;

[0046] Figure 5 is an example diagram of a second embodiment of the optical device provided in this application transmitting optical signals to a medium;

[0047] Figure 6 is a flowchart of the steps of a second embodiment of the phase offset compensation method provided in this application;

[0048] Figure 7 is an example diagram of a third embodiment of the optical device provided in this application transmitting optical signals to a medium;

[0049] Figure 8 is an example of the spectrum of time-domain windowing provided in this application;

[0050] Figure 9 is an example of the frequency windowing spectrum provided in this application;

[0051] Figure 10 is a spectrum example diagram of an embodiment provided in this application;

[0052] Figure 11 is a structural example diagram of the compensation device provided in this application;

[0053] Figure 12 is a structural example diagram of an embodiment of the chip provided in this application. Detailed Implementation

[0054] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0055] This application discloses a phase offset compensation method. First, the structure of the optical device to which the method is applied is described with reference to Figure 1, which is an example diagram of the structure of the optical device provided in this application. The optical device 100 shown in this embodiment includes an optical transmitter, a circulator 104, a coherent receiver 106, and a processor 107. For example, the optical transmitter specifically includes a light source 101, a coupler 102, and a modulator 103. The coherent receiver 106 shown in this example can be a coherent receiver. The light source 101, coupler 102, modulator 103, and circulator 104 are connected in sequence, and the coupler 102, coherent receiver 106, and processor 107 are connected in sequence. The circulator 104 is also connected to the coherent receiver 106. The light source 101 is used to send a first optical signal to the coupler 102. This embodiment does not limit the type of the light source 101. For example, the light source 101 can be a narrow-linewidth laser, a single-frequency laser, a tunable laser, etc. This embodiment takes a narrow-linewidth laser as an example. After receiving the first optical signal from the light source 101, the coupler 102 splits the first optical signal into a second optical signal and local light. When the modulator 103 receives the second optical signal from the coupler 102, it modulates the intensity and frequency of the second optical signal to output probe light. When the circulator 104 receives the probe light from the modulator 103, it inputs the probe light into a medium, which can be any medium such as air or optical fiber used as a sensor. Each detection point in the medium can return echo light to the optical device according to the probe light. The echo light can be backscattered Rayleigh light. The echo light is reflected to the circulator 104, which sends the echo light to the coherent receiver 106. The coherent receiver 106 beats the local light and the echo light to form an electrical signal output. The processor 107 processes the electrical signal to realize detection.

[0056] Optionally, if the light source 101 is a tunable laser, then the light source 101 can directly output the probe light without requiring a modulator in the optical transmitter. Optionally, an amplifier may be included between the circulator 104 and the medium, or between the modulator 103 and the circulator 104. The amplifier is used to amplify the optical power of the probe light to improve the detection efficiency. This embodiment does not limit the type of amplifier; for example, the amplifier may be an erbium-doped fiber amplifier. This embodiment does not limit the type of processor 107, as long as the processor 107 can process electrical signals to achieve detection. For example, the processor 107 may include one or more chips, or one or more integrated circuits. For example, processor 107 may include one or more of the following: neural processing unit (NPU), optical digital signal processor (oDSP), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), system on chip (SoC), central processor unit (CPU), network processor (NP), microcontroller unit (MCU), programmable logic device (PLD), network interface card chip, storage interface chip, or other integrated chip, etc. Specific details will not be elaborated further.

[0057] Based on the optical device shown in Figure 1, this application embodiment provides a phase shift compensation method. For better understanding, the phase shift of the probe light is first explained below. The optical device 100 inputs probe light into a medium, which propagates along the medium, including a probe point. Taking an optical fiber as an example, the probe point refers to an optical fiber segment with a specific spatial resolution. The probe point is used to detect and respond to changes in the external environment. In the absence of external interference, the probe point remains stable, meaning its optical properties (such as light intensity and phase) remain unchanged. When external interference (such as impact force) acts on the probe point, its physical properties (such as length, refractive index, etc.) change. These changes alter the phase of the echo light returned from the probe point to the optical device. The optical device 100 detects the intensity and phase changes of the probe point based on the local light and the echo light. By analyzing these changes, the optical device 100 can detect information such as the type, intensity, and location of the external interference. The sampling rate of the detection point in the medium is limited by the round-trip time of the probe light. The round-trip time of the probe light corresponding to the detection point is defined as 2Ln / c, where L is the length of the optical fiber connecting the detection point and the optical device 100, n is the effective refractive index of the optical fiber core, and c is the speed of light in vacuum. The time interval between different probe lights sent by the optical device to detect the detection point needs to be greater than or equal to 2Ln / c to prevent aliasing between the probe light used to detect the detection point and the echo light returned from the detection point. It can be understood that the sampling rate is limited by the length of the optical fiber connected to the optical device 100. Therefore, there is a contradiction between the length of the optical fiber connected to the optical device 100 and the sampling rate.

[0058] The sampling rate can be improved using FDM (Focus-Distributed Membrane Diode). Specifically, within a single detection cycle, multiple signals are modulated onto different frequencies to obtain the detection light. For example, five signals can be modulated onto f1, f2, f3, f4, and f5, where f1, f2, f3, f4, and f5 represent different frequencies. f1, f2, f3, f4, and f5 can be used to detect the position or parameter of different detection points on the medium; that is, each position or parameter in the medium corresponds to a specific frequency. However, if phase shift occurs between different frequencies in FDM, it will affect the detection performance of the optical device and reduce detection accuracy. The phase shift between different frequencies is caused by the performance of the optical device, the position of the detection point, the performance of the medium, and environmental factors (such as changes in temperature and pressure). During the transmission of different frequencies in the medium, the phase changes relative to each other or relative to an ideal reference frequency can lead to aliasing, causing distortion or indistinguishability of different frequency signals. This aliasing reduces detection accuracy and may even cause the optical device to fail in the process of unpacking the echo light.

[0059] Therefore, the phase offset compensation method provided in this application can improve the sampling rate while reducing the bandwidth required by the optical device and the length of the signal sequence emitted by the optical device. Figure 2 is a flowchart of the first embodiment of the phase offset compensation method provided in this application.

[0060] Step 201: The optical device sends M probe frames to the medium.

[0061] M is any integer greater than or equal to 1. Each probe frame includes N different frequencies, such as f1, f2, and so on up to fN. The optical device generates probe frames including N different frequencies based on FDM. Figure 3 is an example diagram of the first embodiment of the optical device transmitting optical signals to the medium provided in this application. The horizontal axis in Figure 3 represents time, and the vertical axis represents frequency. In this embodiment, N=5 is taken as an example. Then, the 5 frequencies included in the probe frame are arranged in ascending order as f1, f2, f3, f4, and f5. Each probe point in the medium returns echo light to the optical device according to the corresponding frequency. The optical device performs detection based on the echo light. For the description of the detection, please refer to the above description, which will not be repeated here. In two adjacent probe frames, the time interval between the same target frequency fi entering the medium is TX, where TX is greater than or equal to 2Ln / c, where L is the length of the optical fiber connecting the probe point used to reflect fi and the optical device, n is the effective refractive index of the optical fiber core, and c is the speed of light in vacuum. In two adjacent detection frames, when the time interval between the same target frequency *fi* entering the medium is *TX* greater than or equal to 2 *Ln / c*, the overlap of *fi* between adjacent detection frames is effectively avoided, improving detection accuracy. For example, as shown in Figure 3, in two adjacent detection frames, the time interval between the same frequency *f1* entering the medium is *TX* greater than or equal to 2 *Ln / c*, and so on, in two adjacent detection frames, the time interval between the same frequency *f5* entering the medium is *TX* greater than or equal to 2 *Ln / c*. In the same detection frame, the time interval between two adjacent frequencies entering the medium is *T* = *TX / N*. For example, as shown in Figure 3, in the same detection frame, the time interval between two adjacent frequencies *f1* and *f2* entering the medium is *T* = *TX / 5*, effectively avoiding the overlap between two adjacent frequencies in the same detection frame and improving detection accuracy.

[0062] Step 202: The optical device receives M response frames from the medium.

[0063] Each detection point in the medium returns an optical signal to the optical device via the medium according to the corresponding frequency in the detection frame. When the detection frame includes N frequencies, the response frame returned by the medium to the optical device also includes N frequencies. For example, if the detection frame includes f1, f2, f3, f4, and f5, then the response frame returned by the medium to the optical device includes: detection point 1 returning f1 based on detection frame f1; detection point 2 returning f2 based on detection frame f2; detection point 3 returning f3 based on detection frame f3; detection point 4 returning f4 based on detection frame f4; and detection point 5 returning f5 based on detection frame f5.

[0064] Figure 4 is an example diagram of the phase shift shown in Figure 3. As shown in the first coordinate system 400 (the horizontal axis is time), taking a probe frame including f1, f2, and f3 as an example, the probe points in the medium return response frames to the optical device according to the frequencies included in the probe frame. If no phase shift occurs, the waveform of the response frame is as shown in the first waveform 410. In the coordinate system where the first waveform 410 is located, the horizontal axis is time and the vertical axis is phase. If a phase shift occurs, the waveform of the response frame is as shown in the second waveform 411, the third waveform 412, and the fourth waveform 413. For an explanation of the coordinate systems where the second waveform 411, the third waveform 412, and the fourth waveform 413 are located, please refer to the explanation of the coordinate system where the first waveform 410 is located; details will not be repeated here. The second waveform 411 is the waveform corresponding to the response frame returned by the probe point in the medium to the optical device according to the frequency f1 included in the probe frame. The third waveform 412 is the waveform corresponding to the response frame returned by the probe point in the medium to the optical device according to the frequency f2 included in the probe frame. The third waveform 413 is the waveform corresponding to the response frame returned by the probe point in the medium to the optical device according to the frequency f3 included in the probe frame. Combining the second waveform 411, the third waveform 412, and the fourth waveform 413, it can be seen that the waveform corresponding to the response frame returned by the probe point to the optical device according to the frequency f1 included in the probe frame has a phase shift φi. For example, if there is no phase shift in the frequencies in the response frame, the response frame presenting the first waveform 410 is processed to obtain the desired signal sequence s1, s2, and s3. Here, s1 is the signal value corresponding to f1, s2 is the signal value corresponding to f2, and s3 is the signal value corresponding to f3. Because the frequency f1 undergoes a phase shift, it will shift to the second waveform 411. Therefore, the response frame including the frequency f1 is processed to obtain the signal with the phase shift a1s1+φ1. Where a1 is a coefficient of arbitrary value, and φ1 is the phase shift amount at frequency f1. Since a phase shift at frequency f2 will shift to the third waveform 412, signal processing is performed on the response frame including frequency f2 to obtain the phase-shifted signal a2s2+φ2, where a2 is a coefficient of arbitrary value, and φ2 is the phase shift amount at frequency f2. Since a phase shift at frequency f3 will shift to the fourth waveform 413, signal processing is performed on the response frame including frequency f3 to obtain the phase-shifted signal a3s3+φ3, where a3 is a coefficient of arbitrary value, and φ3 is the phase shift amount at frequency f3. The optical device's processor detects the phase-shifted signal, which can lead to distortion and unwrapping failure.

[0065] Step 203: The optical device sends K calibration frames to the medium.

[0066] In this embodiment, taking K=1 as an example, after the optical device sends M probe frames, it sends a calibration frame to the medium. It should be noted that the values ​​of K in this embodiment are optional and not limited, as long as K is any integer greater than or equal to 1. The calibration frame satisfies the following condition:

[0067] Condition 1

[0068] The calibration frame includes W frequencies, where W equals N, and the W frequencies in the calibration frame are each equal to the N frequencies in the probe frame. That is, the magnitude of each of the W frequencies is equal to one of the N frequencies. It can be understood that each probe frame and each calibration frame includes frequencies f1, f2, f3, f4, and f5.

[0069] Condition 2

[0070] In the calibration frame, the time interval between two adjacent frequencies entering the medium out of W frequencies is less than the time interval between two adjacent frequencies entering the medium out of N frequencies in the probe frame. For example, as shown in Figure 3, in the calibration frame, W frequencies enter the medium at the same time to reduce phase compensation errors. In the probe frame, N frequencies enter the medium at different times. For example, in the calibration frame, the difference between the time f5 enters the medium and the time f4 enters the medium is less than the difference between the time f5 enters the medium and the time f4 enters the medium in the probe frame, and so on. The time when a frequency enters the medium can be the time when the frequency enters the medium at its rising or falling edge.

[0071] Condition 3

[0072] In adjacent calibration and probe frames, the time interval between the same target frequency fi entering the medium is TX, where TX is greater than or equal to a preset value. For example, if the medium is optical fiber, the preset value can be 2Ln / c. As shown in Figure 3, in both the probe and calibration frames, the time interval between the same frequency f5 entering the medium is TX. When the time interval TX between the same target frequency fi entering the medium in adjacent calibration and probe frames is greater than or equal to 2Ln / c, interference or overlap between the probe and calibration frames is effectively avoided, thus improving detection accuracy.

[0073] Step 204: The optical device receives K calibration response frames from the medium.

[0074] When an optical device inputs a calibration frame to a medium, each detection point in the medium returns a calibration response frame to the optical device according to each frequency in the calibration frame. For example, if the calibration frame includes f1, f2, f3, f4, and f5, then the calibration response frame also includes f1, f2, f3, f4, and f5.

[0075] Step 205: The optical device compensates for the phase shift of the response frame based on K calibration response frames to obtain the compensated response frame.

[0076] The optical device obtains the phase offset Δφi corresponding to each frequency fi in the response frame based on the calibration response frame, and performs phase compensation on each frequency fi in the response frame using a phase compensation algorithm or circuit to obtain a compensated response frame. Each frequency in the compensated response frame can recover its original phase state. For example, as shown in Figure 4, the optical device can compensate for the phase offset of the second waveform corresponding to the calibration response frame to obtain the first waveform. For explanations of the first and second waveforms, please refer to the corresponding description in Figure 4; details will not be repeated here. The following describes the process by which the optical device obtains the phase offset Δφi corresponding to each frequency fi:

[0077] First, the optical device obtains the signal sequence [a1 xt+φ1, a2 xt+φ2, a3 xt+φ3, a4 xt+φ4, a5 xt+φ5] from each frequency in the calibration response frame after signal processing. This signal sequence includes the signal value xt corresponding to each of the W frequencies in the calibration response. Since the W frequencies in the calibration frame enter the medium at the same time, the signal values ​​corresponding to different frequencies in the signal sequence are the same, and all are xt. Specifically, the signal sequence includes the signal value a1 xt+φ1 corresponding to f1, the signal value a2 xt+φ2 corresponding to f2, and so on, with the signal value a5 xt+φ5 corresponding to f5.

[0078] Secondly, the phase offset Δφi corresponding to the target frequency fi in the calibration response frame is obtained according to the signal sequence. The phase offset corresponding to the target frequency fi is the difference between the signal value corresponding to the target frequency fi and the signal value corresponding to the reference frequency fx. The target frequency fi is any frequency among the W frequencies that is different from the reference frequency fx. For example, in this example, if any two a's of a1, a2, a3, a4, and a5 are equal or approximately equal, and f1 is used as the reference frequency, then the phase offset Δφi corresponding to fi is Δφi = (ai xt + φi) – (a1 xt + φ1) = (ai - a1) + (φi – φ1), where i is any integer greater than 1. In this example, ai and a1 are equal or approximately equal, so ai - a1 = 0. Therefore, Δφi = φi – φ1. Similarly, the phase offset Δφ2 for f2 is (a2 xt + φ2) – (a1 xt + φ1) = φ2 – φ1, the phase offset Δφ3 for f3 is (a3 xt + φ3) – (a1 xt + φ1) = φ3 – φ1, the phase offset Δφ4 for f4 is (a4 xt + φ4) – (a1 xt + φ1) = φ4 – φ1, and the phase offset Δφ4 for f5 is (a5 xt + φ5) – (a1 xt + φ1) = φ4 – φ1. For the first frequency in the calibration response frame (i.e., f1), its phase offset Δφ1 can be assumed to be 0.

[0079] The description of obtaining the phase offset Δφi corresponding to fi in this embodiment is an optional example and is not limited. For example, Δφi can also be obtained through one or more intermediate frequencies. For example, the phase offset Δφi corresponding to fi is Δφi = [(ai xt + φi) – (aj xt + φj)] + [(aj xt + φj) – (a1 xt + φ1)] = φi – φ1, where ai and aj are equal or approximately equal. In this example, ai - aj = 0 is taken as an example. Then, the optical device obtains the phase offset Δφi corresponding to each frequency as shown in Table 1:

[0080] Table 1

[0081] Furthermore, when the phase offset Δφi corresponding to each frequency is calculated, the phase offset corresponding to the first frequency is obtained as the difference between the signal value corresponding to the first frequency and the phase offset corresponding to the second frequency. The first frequency is one of the N frequencies in the response frame, and the second frequency is one of the W frequencies in the verification response frame, and the first frequency and the second frequency are equal.

[0082] For example, as shown above, the first signal sequence of the response frame before phase compensation is: [a1 xt+φ1,a2 xt+φ2,a3 xt+φ3,a4 xt+φ4,a5 xt+φ5].

[0083] Phase compensation is performed on the signal sequence of the response frame to obtain the compensated second signal sequence: [a1 xt+φ1-Δφ1,a2xt+φ2-Δφ2,a3 xt+φ3-Δφ3,a4 xt+φ4-Δφ4,a5 xt+φ5-Δφ5]=[a1 xt+φ1,a2 xt+φ1,a3 xt+φ1,a4 xt+φ1,a5 xt+φ1。

[0084] It is understood that the compensated second signal sequence obtained by the optical device has a constant φ1 offset. The optical device can perform detection based on the compensated second signal sequence. Since the phase offset of each frequency in the response frame is equal, it allows for the correct reconstruction of the signal shape and avoids additional unwrapping failures, thus ensuring detection reliability and improving detection accuracy.

[0085] This example assumes that any two 'a's among a1, a2, a3, a4, and a5 are equal or approximately equal. If the difference between two 'a's among a1, a2, a3, a4, and a5 is relatively large, then multiple calibration response frames can be used to compensate for the phase shift of the response frame to obtain a compensated response frame. For example, the phase shift corresponding to fi can be obtained based on the first and second calibration response frames.

[0086] It should be clarified that the process of the optical device compensating for the phase shift of the response frame based on K calibration response frames to obtain the compensated response frame in this embodiment is an optional example and is not limited. As long as the optical device can compensate for the phase shift of the response frame based on one or more calibration response frames, it is acceptable.

[0087] As shown in Figure 3, taking the simultaneous generation and transmission of W different frequencies to the medium in a calibration frame as an example, another example of W different frequencies in a calibration frame can be found in Figure 5. Figure 5 is an example diagram of a second embodiment of the optical device transmitting optical signals to the medium according to this application. After transmitting M probe frames, the optical device transmits a calibration frame. Different frequencies in the calibration frame enter the medium at different times. For an explanation of the conditions that different frequencies in the calibration frame need to meet to enter the medium, please refer to the above description, which will not be repeated here.

[0088] In this embodiment, different frequencies in the calibration frame can be generated by the same light source or by different light sources, without any specific limitation. If different frequencies in the calibration frame are generated by different light sources, the optical power of the frequencies generated by different light sources is reduced compared to different frequencies being generated by the same light source. If the optical device includes multiple light sources, the modulator needs to switch between different light sources and the circulator. The time interval between the two frequencies entering the medium in the calibration frame can be adjusted according to the switching delay of the modulator.

[0089] It should be clarified that this embodiment uses the optical device to perform the phase offset compensation method to achieve detection as an example, and is not limited. In other examples, the optical device can also perform the phase offset compensation method to achieve communication.

[0090] Using the method shown in this embodiment, after the optical device sends M probe frames to the medium, a calibration frame is sent. The phase offset corresponding to each frequency in the response frame can be obtained through the calibration frame. Based on the phase offset, the purpose of phase compensation for each frequency in the response frame is achieved. Since this embodiment does not need to send a compensation frequency at the same time as sending each frequency in the probe frame, but achieves phase compensation by sending a calibration frame independently, the frequency used to achieve phase compensation will not occupy too much bandwidth of the optical device. While achieving phase compensation, the bandwidth required by the optical device is reduced, the introduced noise is reduced, and the detection accuracy is improved.

[0091] The optical device shown in this embodiment sends M probe frames and one calibration frame to the medium within one probe cycle. While achieving accurate phase compensation for each frequency of the response frame, it avoids crosstalk caused by too many calibration frames on the phase compensation of the response frame, improves the accuracy of phase compensation, and minimizes the impact of calibration frames on signal sampling, effectively improving the sampling rate during the probe process.

[0092] As shown in this embodiment, the optical device can adjust the number of calibration frames sent to the medium within a detection cycle as needed. For example, taking optical fiber as the medium, the number of calibration frames included in a detection cycle can be adjusted according to the state of the optical fiber to which the optical device is connected. If the medium is buried optical fiber, the medium is in a relatively stable state, and the phase shifts of different frequencies in the detection frames are relatively stable, so the number of calibration frames included in a detection cycle can be reduced. If the medium is not buried optical fiber, the medium is in a relatively changing state, and the phase shifts of different frequencies in the detection frames are changing, so the number of calibration frames included in a detection cycle can be increased. Alternatively, the optical device can adjust the number of calibration frames included in a detection cycle based on the number of detection frames sent. For example, after the optical device sends X1 detection frames, changes in the light source frequency or temperature will alter the phase shifts of different frequencies in the detection frames, so the number of calibration frames included in the detection cycle can be increased to achieve recalibration. For example, the number of calibration frames included in the detection cycle can be flexibly adjusted according to the equipment conditions of the optical device. For instance, if the temperature of the light source changes or the frequency emitted by the light source changes, the number of calibration frames included in the detection cycle can be adjusted.

[0093] In the above embodiments, taking the example where the number and size of frequencies included in the calibration frame are equal to those included in the probe frame, in the embodiment corresponding to Figure 6, the frequencies included in the calibration frame are a subset of the frequencies included in the probe frame. The optical device sends multiple calibration frames to the medium in one probe cycle. Figure 6 is a flowchart of the steps of a second embodiment of the phase offset compensation method provided in this application.

[0094] Step 601: The optical device sends the first probe frame to the medium.

[0095] Step 602: The optical device receives the first response frame from the medium.

[0096] For an explanation of the execution process of steps 601 to 602 shown in this embodiment, please refer to steps 201 to 202 corresponding to Figure 2. Detailed explanations will not be repeated here.

[0097] Step 603: The optical device sends the first calibration frame to the medium.

[0098] The first calibration frame shown in this embodiment includes W frequencies, where W is any integer greater than or equal to 1 and less than N. The first probe frame includes N frequencies. For example, if the N frequencies included in the first probe frame specifically include f1, f2, f3, f4, and f5, then the first calibration frame includes a portion of the frequencies from f1, f2, f3, f4, and f5. For instance, the first calibration frame may include f1 and f2. This embodiment does not limit the number of frequencies included in the first calibration frame or the magnitude of each frequency, as long as the first calibration frame includes a portion of the frequencies from the first probe frame. For an explanation of whether f1 and f2 in the first calibration frame meet the conditions, please refer to the embodiment corresponding to Figure 2, which explains how f1 and f2 in the first calibration frame meet the conditions; details will not be elaborated further.

[0099] Step 604: The optical device receives the first calibration response frame from the medium.

[0100] When the optical device inputs a first calibration frame to the medium, each detection point in the medium returns a first calibration response frame to the optical device according to each frequency in the first calibration frame. For example, if the first calibration frame includes f1 and f2, then the first calibration response frame also includes f1 and f2.

[0101] Step 605: The optical device sends a second probe frame to the medium.

[0102] Step 606: The optical device sends a second calibration frame to the medium.

[0103] The optical device shown in this embodiment detects various detection points on the medium within one detection cycle. Figure 7 is an example diagram of a third embodiment of the optical device providing this application transmitting optical signals to the medium. Within the detection cycle, the optical device sequentially transmits a first detection frame, a first calibration frame, a second detection frame, and a second calibration frame to the medium. This embodiment does not limit the number of first and second detection frames included in the detection cycle. Taking a detection cycle including two calibration frames (i.e., a first calibration frame and a second calibration frame) as an example, this embodiment does not limit the number of calibration frames included in the detection cycle; that is, the detection cycle includes K calibration frames, where K is any integer greater than 2. One or more detection frames can be transmitted between two adjacent calibration frames transmitted by the optical device to the medium. The second detection frame shown in this embodiment includes N frequencies. For a description of the second detection frame, please refer to the description of the detection frame corresponding to Figure 2; details will not be repeated here.

[0104] When the first detection period includes K calibration frames, the intersection of any two calibration frames includes R1 frequencies, where R1 is any integer greater than or equal to 1 and less than N. The R1 frequencies are each equal to a subset of the N frequencies. The union of the K calibration frames includes R2 frequencies, where R2 is any integer greater than or equal to N. The N frequencies are each equal to at least a subset of the R2 frequencies. For example, taking the K calibration frames as an example, which include the first and second calibration frames described above, the frequencies included in the first and second calibration frames are each equal to a subset of the N frequencies included in the detection frame. For example, as shown in Figure 7, the first probe frame includes N frequencies f1, f2, f3, f4, and f5, and the first calibration frame includes f1, f2, and f3. Therefore, the second calibration frame must include at least f3, f4, and f5. In this example, the intersection of the first and second calibration frames includes R1 frequencies specifically f3, and the union of the first and second calibration frames includes R2 frequencies specifically f1, f2, f3, f4, and f5. It can be understood that the probe period can include K calibration frames, each calibration frame including a portion of the frequencies in the probe frame, the union of the frequencies in the K calibration frames including all the frequencies in the probe frame, and the intersection of any two adjacent calibration frames in the K calibration frames is not empty, and the frequencies included in the intersection are equal to at least one frequency in the probe frame. For an explanation of the conditions satisfied by the frequencies included in the second calibration frame, please refer to the explanation of the conditions satisfied by the frequencies included in the calibration frame corresponding to Figure 2, which will not be elaborated further here.

[0105] Step 607: The optical device receives a second calibration response frame from the medium.

[0106] When the optical device inputs a second calibration frame to the medium, each detection point in the medium returns a second calibration response frame to the optical device according to each frequency in the second calibration frame. For example, if the second calibration frame includes f3, f4, and f5, then the second calibration response frame also includes f3, f4, and f5.

[0107] Step 608: The optical device receives a second response frame from the medium.

[0108] The second response frame is the response frame returned by the medium to the optical device based on the second detection frame. For an explanation of the second response frame, please refer to the explanation of the response frame corresponding to Figure 2, which will not be elaborated here.

[0109] Step 609: The optical device compensates for the phase shift of the first calibration response frame and the second calibration response frame based on the first calibration response frame and the second calibration response frame to obtain the compensated first response frame and the compensated second response frame.

[0110] In this embodiment, the optical device obtains the phase offset Δφi corresponding to each frequency fi in the first and second calibration response frames based on the first and second calibration response frames, respectively. Then, it performs phase compensation on each frequency fi in the first and second response frames using a phase compensation algorithm or circuit to obtain compensated first and second response frames. Specifically, firstly, the optical device obtains the signal value corresponding to each frequency in the first and second calibration response frames. For a detailed explanation, please refer to Figure 2 for the description of the optical device obtaining the signal value corresponding to each frequency in the calibration response frame; further details are omitted here. Secondly, the optical device obtains the phase offset corresponding to the first target frequency fi1 in the first calibration response frame based on the signal value corresponding to each frequency in the first calibration response frame. The phase offset corresponding to the first target frequency fi1 is the difference between the signal value corresponding to the first target frequency fi1 and the signal value corresponding to the reference frequency fx. The first target frequency fi1 is any frequency in the first calibration response frame that is different from the reference frequency fx. For example, as shown in Figure 7, if f1 is used as the reference frequency, then for the first calibration frame, the explanation of obtaining the phase offset corresponding to f1, the phase offset corresponding to f2, and the phase offset corresponding to f3 is shown in step 205 of Figure 2, which explains how the optical device obtains the phase offset corresponding to each frequency in the response frame. Further details are omitted here. Next, the optical device obtains the phase offset corresponding to the second target frequency fi2 in the second calibration response frame based on the signal value corresponding to each frequency in the second calibration response frame. The phase offset corresponding to the second target frequency fi2 is the sum of a first parameter and a second parameter. The first parameter is the difference between the signal value corresponding to the second target frequency fi2 and the signal value corresponding to the intersection frequency, where the intersection frequency is one of the R1 frequencies. The second parameter is the difference between the signal value corresponding to the intersection frequency and the signal value corresponding to the reference frequency fx. The second target frequency fi2 is any frequency in the second calibration response frame that is different from the intersection frequency. For example, as shown in Figure 7, for instance, the second target frequency fi2 is f5, and the phase offset Δφ5 corresponding to f5 is the sum of the first parameter and the second parameter. Wherein, the first parameter = (a5 xt + φ5) – (aj xt + φj), where aj xt + φj is the signal value of the intersection frequency. Since f3 is the intersection frequency, the first parameter = (a5 xt + φ5) – (a3 xt + φ3). The second parameter = (aj xt + φj) – (a1 xt + φ1). It can be understood that the phase offset Δφ5 corresponding to f5 = φ5 – φ1.Finally, the optical device obtains the phase offset corresponding to the third frequency as the difference between the signal value corresponding to the third frequency and the phase offset corresponding to the fourth frequency. The third frequency is any frequency in the first response frame and the second response frame, and the fourth frequency is one of the frequencies in the first calibration response frame and the second calibration response frame. The third frequency is equal to the fourth frequency. For details, please refer to the description corresponding to Figure 2. Detailed explanation will not be repeated here.

[0111] In this embodiment, each calibration frame within a detection period includes a portion of N frequencies. Therefore, the distribution of the frequencies used for calibration within the detection period is more dispersed. For example, the time slot between the frequencies in the first calibration frame and the frequencies in the second calibration frame is larger than the time slot between two different frequencies in the calibration frame corresponding to Figure 2. This effectively reduces the noise introduced during the phase compensation process and lowers the error of phase compensation.

[0112] In the above method embodiments, the optical device can perform frequency modulation (such as linear frequency modulation) on each frequency included in the frame to improve the frame's sensing distance (or ranging accuracy). Specifically, the optical device improves its ranging capability and resolution by changing the characteristics of each frequency included in the frame to obtain a wider spectrum.

[0113] In the above method embodiments, the optical device can window each frequency included in the probe frame and / or each frequency included in the calibration frame to reduce crosstalk between frequencies, improve the quality of the signal at the end of the medium, and enhance the receiving performance and detection reliability of the optical device. Taking the probe frame as an example, the optical device windowes each frequency included in the probe frame in the time domain and / or the optical device windowes each frequency included in the probe frame in the frequency domain. Taking the calibration frame as another example, the optical device windowes each frequency included in the calibration frame in the time domain and / or the optical device windowes each frequency included in the calibration frame in the frequency domain. For example, Figure 8 is a spectrum example diagram of time-domain windowing provided in this application. The coordinate system shown in Figure 8 is a windowing example diagram for f1 (frequency in the probe frame or frequency in the calibration frame) shown above. The horizontal axis of this coordinate system is time, and the vertical axis is amplitude. Waveform 801 shown in Figure 8 is the waveform of f1 before time-domain windowing, and waveform 802 is the waveform after time-domain windowing of 801. It is understandable that after time-domain windowing of f1, the amplitude of f1 gradually decreases at the edges. Figure 9 is an example of the frequency spectrum of frequency windowing provided in this application. The coordinate system shown in Figure 9 is an example of windowing for f1 (the frequency in the probe frame or the frequency in the calibration frame) as shown above. The horizontal axis of this coordinate system is frequency, and the vertical axis is amplitude. Waveform 901 in Figure 9 is the waveform of f1 before frequency-domain windowing, and waveform 902 is the waveform after frequency-domain windowing of 901. It is understandable that after frequency-domain windowing of f1, the spectrum of f1 becomes more concentrated, and the amplitude of the sidelobes is significantly reduced, which means that crosstalk between frequencies will also be reduced accordingly, thereby reducing spectral leakage and improving the detection performance.

[0114] In this embodiment, the shape of each frequency in the probe frame and calibration frame can be modulated to form a chirped frequency shape as shown in Figure 10, where Figure 10 is a spectrum example diagram of an embodiment provided in this application. Taking f1 as an example, the chirped frequency shape of f1 refers to the phenomenon that the frequency of the f1 frequency signal changes with time. Specifically, within the duration corresponding to f1, the frequency components included in f1 are asynchronous. The description of the frequency shape of each frequency in this embodiment is an optional example and is not limited. In this embodiment, taking the probe frame as an example, the N frequencies included in the probe frame, as shown in Figure 10, may not be sent to the medium in an ascending or descending monotonic order. That is, the order of the N frequencies included in the probe frame sent by the optical device to the medium may be non-monotonic to reduce crosstalk and nonlinear effects. The non-monotonic order of the N frequencies sent by the optical device to the medium can break the frequency correlation between adjacent signals, reduce the electromagnetic coupling strength between them, and thus reduce the occurrence of crosstalk. For example, the frequencies of different signals can be more dispersed to avoid adjacent signals using similar frequencies, thereby reducing the possibility of crosstalk. Taking a calibration frame as an example, the W frequencies included in the calibration frame, as shown in Figure 10, can be sent to the medium in a non-monotonic order, either from smallest to largest or from largest to smallest. That is, the order of the W frequencies in the calibration frame sent by the optical device to the medium can be non-monotonic to reduce crosstalk and nonlinear effects. The non-monotonic order of the W frequencies sent by the optical device to the medium can break the frequency correlation between adjacent signals, reduce their electromagnetic coupling strength, and thus reduce the occurrence of crosstalk. For example, the frequencies of different signals can be more dispersed to avoid adjacent signals using similar frequencies, thereby reducing the possibility of crosstalk.

[0115] Regarding the above method embodiments, it should be noted that:

[0116] (1) The step numbers of the flowcharts described in the embodiments are only examples of the execution flow and do not constitute a restriction on the order of execution of the steps. There is no strict execution order between steps that have no temporal dependency relationship with each other in the embodiments of this application. In addition, not all steps shown in the flowcharts are mandatory steps. Some steps can be added or deleted based on the actual needs of each flowchart.

[0117] (2) In the various embodiments of this application, unless otherwise specified or logically conflicting, the terms and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0118] The methods provided by the embodiments of this application have been described in detail above. The apparatus and chip provided by the embodiments of this application will be described in detail below. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments; therefore, any content not described in detail can be referred to the method embodiments above, and for the sake of brevity, will not be repeated here.

[0119] This application provides an optical device. The structure of this optical device is described in the description corresponding to Figure 1, and will not be repeated here. The process of the optical device performing the phase shift compensation method is described in the description corresponding to Figure 2 or Figure 6 above, and will not be repeated here.

[0120] Figure 11 is a structural example diagram of the compensation device provided in this application. The compensation device 1100 includes a transmitting module 1101, a processing module 1102, and a receiving module 1103. The transmitting module 1101 may also be referred to as a transmitter, transmitting unit, or transmitting device. The receiving module 1103 may also be referred to as a receiver, receiving unit, or receiving device. The processing module 1102 is used to implement corresponding processing functions. The transmitting module 1101 and the receiving module 1103 may also be referred to as a communication interface or communication unit.

[0121] Optionally, the compensation device 1100 further includes a storage unit, which can be used to store instructions and / or data. The processing module 1102 can read the instructions and / or data in the storage unit to execute corresponding processing control actions.

[0122] For example, in the embodiment corresponding to Figure 2, the sending module 1101 is used to execute steps 201 and 203; the processing module 1102 is used to execute step 205; and the receiving module 1103 is used to execute steps 202 and 204. In the embodiment corresponding to Figure 6, the sending module 1101 is used to execute steps 601, 603, 605, and 606; the processing module 1102 is used to execute steps 609 and 610; and the receiving module 1103 is used to execute steps 602, 604, 607, and 608.

[0123] It should be understood that the specific process of each module performing the above-mentioned steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0124] Figure 12 is a structural example diagram of an embodiment of the chip provided in this application. The chip 1200 (or processing system) includes a processing unit 1210 and an interface circuit 1220. The processing unit 1210 can be the processing circuit within the chip 1200. The processing unit 1210 can be coupled to a storage unit, calling instructions from the storage unit, enabling the chip 1200 to implement the methods and functions of the various embodiments of this application. The interface circuit 1220 can be the input / output circuit within the chip 1200, outputting processed information from the chip 1200, or inputting data or signaling information to be processed into the chip 1200 for processing.

[0125] Optionally, the processing unit 1210 may be implemented by one or more processors, including the one or more processors or the processing portion of the one or more processors. Optionally, the interface circuit 1220 may include transceiver circuitry, a network interface card (NIC), input / output circuitry, or a communication interface.

[0126] As one approach, the chip 1200 is used to implement the operations performed by the optical device in the various method embodiments described above.

[0127] Specifically, the processing unit 1210 is used to implement the processing-related operations performed by the optical device in the above method embodiment; the interface circuit 1220 is used to implement the transmission and / or reception-related operations performed by the optical device in the above method embodiment.

[0128] This application also provides a computer-readable storage medium storing computer instructions for implementing the methods executed by the optical device in the above-described method embodiments.

[0129] For example, when the computer program is executed by a computer, it enables the computer to implement the methods executed by the optical device in the various embodiments of the above methods.

[0130] This application also provides a computer program product comprising instructions which, when executed by a computer, implement the methods performed by the optical device in the above-described method embodiments.

[0131] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for compensating for phase shift, characterized in that, The method includes: The optical device sends a probe frame to the medium, the probe frame including N frequencies, where N is any integer greater than 1; The optical device sends K calibration frames to the medium, where K is any integer greater than or equal to 1, and each calibration frame includes W frequencies, where W is any integer greater than or equal to 1 and less than or equal to N, and the W frequencies are equal to at least a portion of the N frequencies. The optical device receives a response frame from the medium, the response frame being a response frame returned by the medium to the optical device based on the probe frame; The optical device receives K calibration response frames from the medium, the K calibration response frames being response frames returned by the medium to the optical device based on the K calibration frames; The optical device compensates for the phase shift of the response frame based on the K calibration response frames to obtain a compensated response frame.

2. The method according to claim 1, characterized in that, The optical device compensates for the phase shift of the response frames based on the K calibration response frames to obtain compensated response frames, including: The optical device obtains the phase offset corresponding to each frequency in the response frame based on the K calibration response frames; The optical device compensates for the phase shift of the response frame based on the phase shift corresponding to each frequency in the response frame, so as to obtain the compensated response frame.

3. The method according to claim 1 or 2, characterized in that, The W is equal to the N, and the W frequencies are equal to the N frequencies respectively.

4. The method according to any one of claims 1 to 3, characterized in that, The optical device compensates for the phase shift of the response frames based on the K calibration response frames to obtain compensated response frames, including: The optical device obtains the signal value corresponding to each frequency in the calibration response frame; The optical device obtains the phase offset corresponding to the target frequency fi in the calibration response frame based on the signal value corresponding to each frequency in the calibration response frame. The phase offset corresponding to the target frequency fi is the difference between the signal value corresponding to the target frequency fi and the signal value corresponding to the reference frequency fx. The target frequency fi is any frequency among the W frequencies that is different from the reference frequency fx. The optical device obtains the phase offset corresponding to the first frequency as the difference between the signal value corresponding to the first frequency and the phase offset corresponding to the second frequency. The first frequency is one of N frequencies in the response frame, and the second frequency is one of W frequencies in the calibration response frame, and the first frequency and the second frequency are equal.

5. The method according to claim 1, characterized in that, K is greater than 1, W is less than N, the intersection of any two calibration frames in the K calibration frames includes R1 frequencies, R1 is any integer greater than or equal to 1 and less than N, the R1 frequencies are equal to some of the N frequencies, the union of the K calibration frames includes R2 frequencies, R2 is any integer greater than or equal to N, the N frequencies are equal to at least some of the R2 frequencies.

6. The method according to claim 5, characterized in that, The K calibration response frames include a first calibration response frame and a second calibration response frame. The optical device compensates for the phase shift of the response frames based on the K calibration response frames to obtain compensated response frames, including: The optical device obtains the signal value corresponding to each frequency in the first calibration response frame and the second calibration response frame; The optical device obtains the phase offset corresponding to the first target frequency fi1 in the first calibration response frame based on the signal value corresponding to each frequency in the first calibration response frame. The phase offset corresponding to the first target frequency fi1 is the difference between the signal value corresponding to the first target frequency fi1 and the signal value corresponding to the reference frequency fx. The first target frequency fi1 is any frequency in the first calibration response frame that is different from the reference frequency fx. The first calibration response frame includes the reference frequency fx. The optical device obtains the phase offset corresponding to the second target frequency fi2 in the second calibration response frame based on the signal value corresponding to each frequency in the second calibration response frame. The phase offset corresponding to the second target frequency fi2 is the sum of the first parameter and the second parameter. The first parameter is the difference between the signal value corresponding to the second target frequency fi2 and the signal value corresponding to the intersection frequency. The intersection frequency is one of the R1 frequencies. The second parameter is the difference between the signal value corresponding to the intersection frequency and the signal value corresponding to the reference frequency fx. The second target frequency fi2 is any frequency in the second calibration response frame that is different from the intersection frequency. The optical device obtains the phase offset corresponding to the third frequency as the difference between the signal value corresponding to the third frequency and the phase offset corresponding to the fourth frequency. The third frequency is any frequency in the first response frame and the second response frame, and the fourth frequency is one of the frequencies in the first calibration response frame and the second calibration response frame. The third frequency is equal to the fourth frequency.

7. The method according to any one of claims 1 to 6, characterized in that, The time interval between two adjacent frequencies entering the medium among the W frequencies is less than the time interval between two adjacent frequencies entering the medium among the N frequencies.

8. The method according to any one of claims 1 to 7, characterized in that, The optical device sends M detection frames to the medium, where M is any integer greater than 1. In the M detection frames, the time interval between two adjacent detection frames with the same target frequency entering the medium is TX, where TX is greater than or equal to a preset value. In the detection frames, the time interval between two adjacent frequencies entering the medium is T = TX / N.

9. The method according to any one of claims 1 to 8, characterized in that, In adjacent calibration frames and detection frames, the time interval between the same target frequency entering the medium is TX, where TX is greater than or equal to a preset value.

10. The method according to claim 8 or 9, characterized in that, If the medium is an optical fiber, the preset value is 2Ln / c, where L is the length of the optical fiber connecting the detection point used to reflect the target frequency and the optical device, n is the effective refractive index of the optical fiber core, and c is the speed of light in a vacuum.

11. The method according to any one of claims 1 to 10, characterized in that, Before the optical device sends a probe frame to the medium, the method further includes: The optical device applies a window to the frequencies included in the detection frame in the time domain and / or in the frequency domain.

12. The method according to any one of claims 1 to 11, characterized in that, Before the optical device sends a calibration frame to the medium, the method further includes: The optical device applies a window to the frequencies included in the calibration frame in the time domain and / or in the frequency domain.

13. The method according to any one of claims 1 to 12, characterized in that, The optical device sends a probe frame to the medium, including: The optical device transmits the N frequencies included in the detection frame to the medium in a non-monotonic order.

14. The method according to any one of claims 1 to 13, characterized in that, The optical device sends a calibration frame to the medium, including: The optical device transmits the W frequencies included in the calibration frame to the medium in a non-monotonic order.

15. A compensation device, characterized in that, It includes a sending module, a processing module, and a receiving module; The transmitting module is configured to transmit a probe frame to the medium, the probe frame including N frequencies, where N is any integer greater than 1; and to transmit K calibration frames to the medium, where K is any integer greater than or equal to 1, the calibration frame including W frequencies, where W is any integer greater than or equal to 1 and less than or equal to N, and the W frequencies are equal to at least a portion of the N frequencies. The receiving module is configured to receive a response frame from the medium, the response frame being a response frame returned by the medium to the optical device based on the probe frame, and is further configured to receive K calibration response frames from the medium, the K calibration response frames being response frames returned by the medium to the optical device based on the K calibration frames. The processing module is used to compensate for the phase shift of the response frame based on the K calibration response frames to obtain a compensated response frame.

16. The compensation device according to claim 15, characterized in that, The W is equal to the N, and the W frequencies are equal to the N frequencies respectively.

17. The compensation device according to claim 15, characterized in that, K is greater than 1, W is less than N, the intersection of any two calibration frames in the K calibration frames includes R1 frequencies, R1 is any integer greater than or equal to 1 and less than N, the R1 frequencies are equal to some of the N frequencies, the union of the K calibration frames includes R2 frequencies, R2 is any integer greater than or equal to N, the N frequencies are equal to at least some of the R2 frequencies.

18. An optical device, characterized in that, Includes optical transmitters, optical receivers, and processors; The optical transmitter is used to send probe frames to the medium, the probe frames including N frequencies, where N is any integer greater than 1, and is also used to send K calibration frames to the medium, where K is any integer greater than or equal to 1, the calibration frames including W frequencies, where W is any integer greater than or equal to 1 and less than or equal to N, and the W frequencies are equal to at least some of the N frequencies. The optical receiver is configured to receive response frames from the medium, the response frames being response frames returned by the medium to the optical device based on the probe frames, and is also configured to receive K calibration response frames from the medium, the K calibration response frames being response frames returned by the medium to the optical device based on the K calibration frames. The processor is used to compensate for the phase shift of the response frame based on the K calibration response frames to obtain a compensated response frame.

19. A chip, characterized in that, It includes at least one processing unit and an interface circuit, the interface circuit being used to provide program instructions or data to the at least one processing unit, the at least one processing unit being used to execute the program instructions to implement the method of any one of claims 1 to 14.

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