A sensing and positioning method and system based on coherent optical communication

Abstract

The application discloses a sensing and positioning method and system based on coherent optical communication, and relates to the technical field of optical switching and optical interconnection networks.The sensing and positioning method based on coherent optical communication comprises the following steps: arranging a plurality of monitoring areas along a first direction and a second direction between a sending end and a receiving end; and utilizing 2N+1 or 2M optical fibers to form the round trip transmission of signals at both ends of a transmission link along the first direction and the second direction, so that the position of a polarization state change event occurring in the monitoring area can be determined by calculating the time difference of 2N+1 or 2M events.The application can position the polarization state change event in a one-way transmission link or position the event without time synchronization in a two-way transmission link.

Description

Technical Field

[0001] This application relates to the fields of optical switching and optical interconnection network technology, and specifically to a sensing and positioning method and system based on coherent optical communication. Background Technology

[0002] With the booming development of the optical communication industry over the past 30 years, major telecom operators around the world have deployed millions of kilometers of various optical fibers in land and sea environments. Optical fibers, as communication infrastructure, constitute a vast communication network that spans the globe.

[0003] Although optical fibers were originally used for communication, they can also serve as distributed sensors because mechanical strain and temperature fluctuations in the fiber cause localized changes in the fiber waveguide properties, resulting in perceptible changes in the transmitted optical signal, such as phase shifts or polarization variations. Typically, distributed optical fiber sensing systems offer advantages such as wide coverage, resistance to electromagnetic interference, high sensitivity, and large bandwidth, enabling the achievement of very high spatial resolution.

[0004] However, because implementing sensing functions requires specific wavelength channels or optoelectronic devices, and may interfere with existing communication services, it results in high construction and operation costs when deployed on existing telecommunications networks. Sensing technology based on SOP (State of polarization) changes can be implemented using communication signals, eliminating the need for dedicated sensing signals and devices. It can detect external environmental factors such as vibrations and lightning strikes, making it an effective technical solution for building integrated sensing and communication networks in the future. Currently, polarization state monitoring is implemented in the digital signal processing at the receiving end of the coherent optical communication link. It can sense the rate and magnitude of polarization state changes, but event localization requires bidirectional communication and precise time synchronization, making it unsuitable for unidirectional communication links. Summary of the Invention

[0005] This application provides a sensing and positioning method and system based on coherent optical communication, which can locate polarization state change events in a unidirectional transmission link, or locate events in a bidirectional transmission link without time synchronization.

[0006] In a first aspect, embodiments of this application provide a sensing and positioning method based on coherent optical communication, the sensing and positioning method based on coherent optical communication comprising:

[0007] Multiple monitoring zones are arranged between the transmitting and receiving ends along the first and second directions;

[0008] Using 2N+1 optical fibers, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the first direction, 2N+1 polarization state changes are generated on the optical signal, where N is the sequence number of the monitoring area arranged in the first direction.

[0009] Using a 2M segment of optical fiber, a round-trip signal transmission is established at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring area arranged in the second direction.

[0010] The filter coefficients of each monitoring area are extracted to calculate the Stokes vector of the current optical signal. Based on the changes in the time-domain waveform of the Stokes vector, the occurrence time of the polarization state change is obtained to determine the location of the intrusion point in the monitoring area.

[0011] In conjunction with the first aspect, in one implementation, the step of extracting the filter coefficients of each monitoring area to calculate the Stokes vector of the current optical signal includes:

[0012] Extract the coefficients of the filter's x-polarization or y-polarization, and calculate the components of the Stokes vector based on these coefficients.

[0013] In conjunction with the first aspect, in one implementation, when extracting the coefficients of the filter x-polarization:

[0014] According to the formula: Calculate the coefficients {F} of the x-polarization filter. xx ,F xy}, where L is the filter length;

[0015] According to the formula:

[0016] S0=|F xx | 2 +|F xy | 2 S1 = [|F xx | 2 -|F xy | 2 ] / S0, S2 = -2Re(F xx ·F xy ) / S0 and S3 = -2Im(F xx ·F xy S0, S1, S2, S3, S3 are the four components of the Stokes vector.

[0017] In conjunction with the first aspect, in one implementation, obtaining the occurrence time of polarization state changes based on the changes in the time-domain waveform using Stokes vectors to determine the location of the intrusion point in the monitored area includes:

[0018] When the monitoring area is arranged in the first direction, and the time-domain waveform of the Stokes vector shows three fluctuations, the occurrence times of the three polarization state changes are recorded as T1, T2, and T3.

[0019] According to the formula: and Determine the location of the intrusion point, where, in the transmission link, A is the input point, B is the output point, C is the intrusion point, and L... AC L is the distance between AC. BC L is the distance between B and C. AB AB is the distance between A and B, and V is the transmission rate of the optical signal in the optical fiber.

[0020] In conjunction with the first aspect, in one implementation, obtaining the occurrence time of polarization state changes based on the changes in the time-domain waveform using Stokes vectors to determine the location of the intrusion point in the monitored area includes:

[0021] When the monitoring area is arranged in the second direction, and the time-domain waveform of the Stokes vector shows two fluctuations, the occurrence times of the two polarization state changes are recorded as T1 and T2.

[0022] According to the formula: and Determine the location of the intrusion point, where, in the transmission link, A is the input point, B is the output point, C is the return point, D is the intrusion point, and L... CD L is the distance between CD. AD L is the distance between AD. BD L is the distance between B and D. AC It is the distance between AC, and V is the transmission rate of the optical signal in the optical fiber.

[0023] In conjunction with the first aspect, in one embodiment, the first direction is the transmission direction of the optical signal, and the second direction is a direction perpendicular to the transmission direction.

[0024] Secondly, embodiments of this application provide a sensing and positioning system based on coherent optical communication, the sensing and positioning system based on coherent optical communication comprising:

[0025] The transmitter and receiver are provided, wherein the transmitter is used to output optical signals, and multiple monitoring areas are arranged between the transmitter and receiver along a first direction and a second direction.

[0026] The monitoring area is configured as follows:

[0027] Using 2N+1 optical fibers, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the first direction, 2N+1 polarization state changes are generated on the optical signal, where N is the sequence number of the monitoring area arranged in the first direction.

[0028] Using a 2M segment of optical fiber, a round-trip signal transmission is established at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring area arranged in the second direction.

[0029] The filter coefficients are extracted to calculate the Stokes vector of the current optical signal. Based on the changes in the time-domain waveform of the Stokes vector, the occurrence time of the polarization state change is obtained to determine the location of the intrusion point in the monitoring area.

[0030] In conjunction with the second aspect, in one implementation, the process of extracting filter coefficients in the monitoring area to calculate the Stokes vector of the current optical signal includes:

[0031] Extract the coefficients of the filter's x-polarization or y-polarization, and calculate the components of the Stokes vector based on these coefficients.

[0032] In conjunction with the second aspect, in one implementation, when extracting the coefficients of the filter x-polarization:

[0033] According to the formula: Calculate the coefficients {F} of the x-polarization filter. xx ,F xy}, where L is the filter length;

[0034] According to the formula:

[0035] S0=|F xx | 2 +|F xy | 2 S1 = [|F xx | 2 -|F xy | 2 ] / S0, S2 = -2Re(F xx ·F xy ) / S0 and S3 = -2Im(F xx ·F xy S0, S1, S2, S3, S3 are the four components of the Stokes vector.

[0036] In conjunction with the second aspect, in one embodiment, the first direction is the transmission direction of the optical signal, and the second direction is a direction perpendicular to the transmission direction.

[0037] The beneficial effects of the technical solutions provided in this application include at least the following:

[0038] The sensing and positioning method based on coherent optical communication in this application involves arranging multiple monitoring zones along a first and a second direction between a transmitting end and a receiving end; using 2N+1 optical fiber segments to form a round-trip signal transmission at both ends of the transmission link, such that when a polarization state change event occurs at a point on the transmission link of a monitoring zone arranged in the first direction, 2N+1 polarization state changes are generated in the optical signal, where N is the sequence number of the monitoring zone arranged in the first direction; using 2M optical fiber segments to form a round-trip signal transmission at both ends of the transmission link, such that when a polarization state change event occurs at a point on the transmission link of a monitoring zone arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring zone arranged in the second direction; the filter coefficients of each monitoring zone are extracted to calculate the Stokes vector of the current optical signal, and based on the changes in the time-domain waveform of the Stokes vector, the occurrence time of the polarization state change is obtained to determine the location of the intrusion point in the monitoring zone.

[0039] This application is based on a unidirectional point-to-point coherent optical communication transmission link, utilizing 2N+1 or 2M fiber segments, and establishing a round-trip signal transmission at both ends of the transmission link. When a polarization state change event occurs at a certain point in the link, it will correspondingly produce 2N+1 or 2M polarization state changes in the signal. By calculating the time difference between these 2N+1 or 2M events, the location of the event can be determined. In dual-fiber bidirectional or single-fiber bidirectional optical communication links, the same principle can be used to establish a round-trip signal transmission using 2N+1 or 2M fiber segments, thereby achieving positioning without the need for time synchronization. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating an embodiment of the sensing and positioning method based on coherent optical communication according to this application;

[0041] Figure 2 This is a block diagram of the sensing and positioning system based on coherent optical communication according to this application;

[0042] Figure 3 This is a block diagram of the algorithm for polarization state monitoring based on an adaptive filter in this application;

[0043] Figure 4 This is a schematic diagram of the method for achieving positioning in the first direction according to this application;

[0044] Figure 5 This is a schematic diagram of the method for achieving positioning in the second direction according to this application. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0046] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0047] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0048] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0049] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0050] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0051] In a first aspect, embodiments of this application provide a sensing and positioning method based on coherent optical communication.

[0052] In one embodiment, reference is made to Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the sensing and positioning method based on coherent optical communication according to this application. Figure 1 As shown, the sensing and localization method based on coherent optical communication includes:

[0053] S1. Multiple monitoring zones are arranged between the transmitting end and the receiving end along the first and second directions;

[0054] For details, please refer to Figure 2 As shown, multiple monitoring zones are arranged between the transmitting end and the receiving end along the first and second directions: Monitoring Zone 1 and Monitoring Zone 2.

[0055] In this embodiment, the first direction is the transmission direction of the optical signal, and the second direction is a direction perpendicular to the transmission direction. Of course, other directions can be set as needed, and this embodiment does not impose any restrictions.

[0056] S3. Using 2N+1 optical fibers, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point of the transmission link of the monitoring area arranged in the first direction, 2N+1 polarization state changes are generated on the optical signal, where N is the sequence number of the monitoring area arranged in the first direction.

[0057] In this embodiment, N = 1, 2, 3..., and the two ends of the transmission link refer to the input monitoring area and the output from the monitoring area. It can be understood that for monitoring area 1 and monitoring area 2 in the first direction, the value of N is 1 and 2 respectively. That is to say, when a polarization state change event occurs at a point of the transmission link in monitoring area 1, the optical signal will undergo 3 polarization state changes, and when a polarization state change event occurs at a point of the transmission link in monitoring area 2, the optical signal will undergo 5 polarization state changes.

[0058] S3. Using a 2M segment of optical fiber, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the second direction, 2M polarization state changes are generated on the optical signal, where M is the sequence number of the monitoring area arranged in the second direction.

[0059] In this embodiment, M = 1, 2, 3... The principle of monitoring zone 1 and monitoring zone 2 in the second direction is similar to that of monitoring zone 1 and monitoring zone 2 in the first direction, and will not be described in detail here.

[0060] S4. Extract the filter coefficients of each monitoring area to calculate the Stokes vector of the current optical signal. Based on the changes in the time-domain waveform of the Stokes vector, obtain the occurrence time of the polarization state change to determine the location of the intrusion point in the monitoring area.

[0061] Polarization state sensing is implemented in the monitoring area and the digital signal processing module at the receiver end of the coherent optical communication system. First, the Stokes vector of the current optical signal is calculated by extracting the filter coefficients F from the adaptive filter module. The Stokes vector describes the polarization state of the optical signal; its value remains essentially constant when the polarization state is fixed, but fluctuates in the time domain when the polarization state changes. Since external environmental factors such as vibrations or lightning strikes on the optical fiber link can cause changes in the polarization state of the optical signal, monitoring the time-domain waveform of the Stokes vector at the receiver end allows for the monitoring of these events.

[0062] The process is described in further detail below:

[0063] The system block diagram of the polarization state monitoring algorithm involved in this application is as follows: Figure 3 As shown in the diagram, the dashed line represents the algorithm structure of a traditional adaptive filter. This application calculates the polarization state based on extracting filter coefficients. In the algorithm module of a traditional adaptive filter, the filter coefficients F are updated as follows:

[0064] F xx (l,g+1)=F xx (l,g)+4με x Eout x (n)[Ein x (nl)] * (1)

[0065] F xy (l,g+1)=F xy (l,g)+4με x Eout x (n)[Ein y (nl)] * (2)

[0066] F yx (l,g+1)=F yx (l,g)+4με y Eout y (n)[Ein x (nl)] * (3)

[0067] F yy (l,g+1)=F yy (l,g)+4μεy Eout y (n)[Ein y (nl)] * (4)

[0068] In this algorithm, Ein is the input to the adaptive filter, Eout is the output, x and y represent two polarization states, g represents the F value before the update, g+1 represents the F value after the update, μ is a small coefficient that controls the update rate of the coefficient F, and ε is the error value for the coefficient update. Adaptive filters, depending on the error calculation method, mainly employ the Constant Modulus Algorithm (CMA) and the Least Mean Square (LMS) algorithm.

[0069] To achieve polarization state monitoring, the adaptive filter coefficients F are first extracted. The filter length is L. During calculation, the coefficients in the four directions are summed using complex numbers.

[0070]

[0071]

[0072]

[0073]

[0074] Then the polarization state of the optical signal is calculated, where there are two sets of coefficients {F}. xx ,F xy}, {F yx ,F yy} represents the coefficients for x-polarization and y-polarization, respectively. Since x and y are 90 degrees apart, only one polarization needs to be calculated to reflect the change in polarization state. Here, we take x-polarization as an example for calculation:

[0075] S0=|F xx | 2 +|F xy | 2 (9)

[0076] S1=[|F xx | 2 -|F xy | 2 ] / S0 (10)

[0077] S2=-2Re(F xx ·F xy ) / S0 (11)

[0078] S3=-2Im(F xx·F xy ) / S0 (12)

[0079] This yields the Stokes vector {S1, S2, S3} used to describe the polarization state. It's worth noting that the Stokes vector contains four components: S0, S1, S2, and S3. Vectors S0, S1, and S2 describe the linear polarization state of the wave, while vector S3 describes the circular polarization state. If S0 is ignored, the polarization state can be determined by dividing S1, S2, and S3 by S... o We can obtain the normalized Stokes vector {S1, S2, S3}.

[0080] When the polarization state is stable, the Stokes vector remains essentially unchanged. When the optical fiber encounters vibration or lightning strike, the polarization state of the optical signal propagating in the fiber changes, and the Stokes vector will exhibit a corresponding fluctuation state in the time domain.

[0081] In the first direction, specifically in this application, without loss of generality, the simplest case will be described, see [reference]. Figure 4 As shown, this is a unidirectional transmission link with points A and B at its two ends. A is the transmitting end (input point), and B is the receiving end (output point). In the digital signal processing module at the receiving end of point B, the changes in the three vectors {S1, S2, S3} are monitored in real time according to the algorithm described above (Formula 5-12). When vibrations or lightning strikes from the external environment act on point C of the transmission link, three changes in the waveforms {S1, S2, S3} will be monitored, with the times recorded as T1, T2, and T3 respectively.

[0082] Then, the position of point C is calculated based on the time difference between the SOP disturbance event monitored at point B:

[0083]

[0084]

[0085]

[0086] In the transmission link, A is the input point, B is the output point, C is the intrusion point, and L... AC L is the distance between AC. BC L is the distance between B and C. AB L is the distance between A and B, and V is the transmission rate of the optical signal in the optical fiber. AB Since the distance is fixed, the time difference between T1 and T3 is relatively fixed, and the relative position of T2 between T1 and T3 is the distance between point C and points B and A.

[0087] Understandably, based on the above principles, the intrusion points corresponding to monitoring zones 1 and 2 in the first direction can be determined.

[0088] In the second direction, specifically in this application, without loss of generality, and using the simplest case as an example, see [link to relevant documentation]. Figure 5 As shown, this is a unidirectional transmission link with points A and B at its two ends. A is the transmitting end (input point), and B is the receiving end (output point). In the digital signal processing module at the receiving end of point B, the changes in the three vectors {S1, S2, S3} are monitored in real time according to the algorithm described above (Formula 5-12). When vibrations or lightning strikes from the external environment act on point C of the transmission link, two changes in the waveforms {S1, S2, S3} will be monitored, with the times recorded as T1 and T2 respectively.

[0089] Then, the location of point D is calculated based on the time difference between the SOP disturbance event monitored at point B:

[0090]

[0091]

[0092] Among them, L CD L is the distance between CD. AD L is the distance between AD. BD L is the distance between B and D. AC L is the distance between AC, and V is the transmission rate of the optical signal in the optical fiber. AC Once fixed, the relative position of the intrusion point D can be calculated.

[0093] Understandably, based on the above principles, the intrusion points corresponding to monitoring zones 1 and 2 in the second direction can be determined.

[0094] Furthermore, it's worth noting that this embodiment divides the monitoring area into two types: the signal transmission direction and the vertical direction. This allows for the differentiation of different monitoring zones by utilizing the varying number of round-trip transmissions via optical fiber. In the transmission direction, the number of round-trip transmissions is odd (2N+1); in the vertical direction, the number of round-trip transmissions is even (2N). Therefore, based on the number of SOP disturbance events detected and the event difference, the specific monitoring area and location can be pinpointed.

[0095] Furthermore, the method described above is implemented by adding some algorithms to the digital signal processing module of the coherent optical receiver module. It is designed for unidirectional communication scenarios and does not add sensing wavelength channels or optoelectronic devices. It can achieve targeted functional upgrades in existing coherent optical transmission links.

[0096] The sensing and positioning method based on coherent optical communication in this application involves arranging multiple monitoring zones along a first and a second direction between a transmitting end and a receiving end; using 2N+1 optical fiber segments to form a round-trip signal transmission at both ends of the transmission link, such that when a polarization state change event occurs at a point on the transmission link of a monitoring zone arranged in the first direction, 2N+1 polarization state changes are generated in the optical signal, where N is the sequence number of the monitoring zone arranged in the first direction; using 2M optical fiber segments to form a round-trip signal transmission at both ends of the transmission link, such that when a polarization state change event occurs at a point on the transmission link of a monitoring zone arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring zone arranged in the second direction; the filter coefficients of each monitoring zone are extracted to calculate the Stokes vector of the current optical signal, and based on the changes in the time-domain waveform of the Stokes vector, the occurrence time of the polarization state change is obtained to determine the location of the intrusion point in the monitoring zone.

[0097] This application is based on a unidirectional point-to-point coherent optical communication transmission link, utilizing 2N+1 or 2M fiber segments, and establishing a round-trip signal transmission at both ends of the transmission link. When a polarization state change event occurs at a certain point in the link, it will correspondingly produce 2N+1 or 2M polarization state changes in the signal. By calculating the time difference between these 2N+1 or 2M events, the location of the event can be determined. In dual-fiber bidirectional or single-fiber bidirectional optical communication links, the same principle can be used to establish a round-trip signal transmission using 2N+1 or 2M fiber segments, thereby achieving positioning without the need for time synchronization.

[0098] Secondly, embodiments of this application also provide a sensing and positioning system based on coherent optical communication.

[0099] In one embodiment, reference is made to Figure 2 , Figure 2 This is a structural block diagram of an embodiment of the sensing and positioning system based on coherent optical communication according to this application. Figure 2 As shown, the sensing and positioning system based on coherent optical communication includes:

[0100] The transmitter and receiver are provided, wherein the transmitter is used to output optical signals, and multiple monitoring areas are arranged between the transmitter and receiver along a first direction and a second direction.

[0101] The monitoring area is configured as follows:

[0102] Using 2N+1 optical fibers, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the first direction, 2N+1 polarization state changes are generated on the optical signal, where N is the sequence number of the monitoring area arranged in the first direction.

[0103] Using a 2M segment of optical fiber, a round-trip signal transmission is established at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring area arranged in the second direction.

[0104] The filter coefficients are extracted to calculate the Stokes vector of the current optical signal. Based on the changes in the time-domain waveform of the Stokes vector, the occurrence time of the polarization state change is obtained to determine the location of the intrusion point in the monitoring area.

[0105] Further, in one embodiment, the process of extracting filter coefficients in the monitoring area to calculate the Stokes vector of the current optical signal includes:

[0106] Extract the coefficients of the filter's x-polarization or y-polarization, and calculate the components of the Stokes vector based on these coefficients.

[0107] Furthermore, in one embodiment, when extracting the coefficients of the filter x-polarization:

[0108] According to the formula: Calculate the coefficients {F} of the x-polarization filter. xx ,F xy}, where L is the filter length;

[0109] According to the formula:

[0110] S0=|F xx | 2 +|F xy | 2 S1 = [|F xx | 2 -|F xy | 2 ] / S0, S2 = -2Re(F xx ·F xy ) / S0 and S3 = -2Im(F xx ·F xy S0, S1, S2, S3, S3 are the four components of the Stokes vector.

[0111] Furthermore, in one embodiment, obtaining the occurrence time of polarization state change based on the changes in the time-domain waveform using Stokes vectors to determine the location of the intrusion point in the monitored area includes:

[0112] When the monitoring area is arranged in the first direction, and the time-domain waveform of the Stokes vector shows three fluctuations, the occurrence times of the three polarization state changes are recorded as T1, T2, and T3.

[0113] According to the formula: and Determine the location of the intrusion point, where, in the transmission link, A is the input point, B is the output point, C is the intrusion point, and L... AC L is the distance between AC. BC L is the distance between B and C. AB AB is the distance between A and B, and V is the transmission rate of the optical signal in the optical fiber.

[0114] Furthermore, in one embodiment, obtaining the occurrence time of polarization state change based on the changes in the time-domain waveform using Stokes vectors to determine the location of the intrusion point in the monitored area includes:

[0115] When the monitoring area is arranged in the second direction, and the time-domain waveform of the Stokes vector shows two fluctuations, the occurrence times of the two polarization state changes are recorded as T1 and T2.

[0116] According to the formula: and Determine the location of the intrusion point, where, in the transmission link, A is the input point, B is the output point, C is the return point, D is the intrusion point, and L... CD L is the distance between CD. AD L is the distance between AD. BD L is the distance between B and D. AC It is the distance between AC, and V is the transmission rate of the optical signal in the optical fiber.

[0117] Furthermore, in one embodiment, the first direction is the transmission direction of the optical signal, and the second direction is a direction perpendicular to the transmission direction.

[0118] It is understood that the functional implementation of each device in the above-mentioned sensing and positioning system based on coherent optical communication corresponds to the steps in the above-mentioned sensing and positioning method embodiment based on coherent optical communication, and their functions and implementation processes will not be described in detail here.

[0119] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A sensing and positioning method based on coherent optical communication, characterized in that, The sensing and localization method based on coherent optical communication includes: Multiple monitoring zones are arranged between the transmitting and receiving ends along the first and second directions; Using 2N+1 optical fibers, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the first direction, 2N+1 polarization state changes are generated on the optical signal, where N is the sequence number of the monitoring area arranged in the first direction. Using a 2M segment of optical fiber, a round-trip signal transmission is established at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring area arranged in the second direction. Extract the filter coefficients of each monitoring area to calculate the Stokes vector of the current optical signal. Based on the changes in the time-domain waveform of the Stokes vector, obtain the occurrence time of the polarization state change to determine the location of the intrusion point in the monitoring area. The changes in the time-domain waveform based on the Stokes vector are used to obtain the occurrence time of polarization state changes in order to determine the location of the intrusion point in the monitored area, including: When the monitoring area is arranged in the first direction, and the time-domain waveform of the Stokes vector shows three fluctuations, the occurrence of the three polarization state changes is recorded as follows: T 1. T 2 and T 3; According to the formula: , and To determine the location of the intrusion point, in the transmission link, A is the input point, B is the output point, and C is the intrusion point. L AC It is the distance between AC. L BC It is the distance between B and C. L AB is the distance between A and B, and V is the transmission rate of the optical signal in the optical fiber; The first direction is the transmission direction of the optical signal, and the second direction is a direction perpendicular to the transmission direction.

2. The sensing and positioning method based on coherent optical communication as described in claim 1, characterized in that: The step of extracting the filter coefficients of each monitoring area and calculating the Stokes vector of the current optical signal includes: Extract the coefficients of the filter's x-polarization or y-polarization, and calculate the components of the Stokes vector based on these coefficients.

3. The sensing and positioning method based on coherent optical communication as described in claim 2, characterized in that, When extracting the coefficients of the filter's x-polarization: According to the formula: , Calculate the coefficients of the filter's x-polarization { , }, where L is the filter length; According to the formula: , , and To obtain the Stokes vector ,in These are the four components of the Stokes vector.

4. The sensing and positioning method based on coherent optical communication as described in claim 1, characterized in that, The method of obtaining the time-domain waveform changes based on Stokes vectors to determine the occurrence time of polarization state changes in order to identify the location of intrusion points in the monitored area also includes: When the monitoring area is arranged in the second direction, and the time-domain waveform of the Stokes vector shows two fluctuations, the occurrence of the two polarization state changes is recorded as follows: T 1 and T 2, According to the formula: and To determine the location of the intrusion point, in the transmission link, A is the input point, B is the output point, C is the turnaround point, and D is the intrusion point. L CD It is the distance between CDs. L AD It is the distance between A and D. L BD It is the distance between B and D. L AC It is the distance between AC, and V is the transmission rate of the optical signal in the optical fiber.

5. A sensing and positioning system based on coherent optical communication, characterized in that, The sensing and positioning system based on coherent optical communication includes: The transmitter and receiver are provided, wherein the transmitter is used to output optical signals, and multiple monitoring areas are arranged between the transmitter and receiver along a first direction and a second direction. The monitoring area is configured as follows: Using 2N+1 optical fibers, a round-trip signal transmission is formed at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the first direction, 2N+1 polarization state changes are generated on the optical signal, where N is the sequence number of the monitoring area arranged in the first direction. Using a 2M segment of optical fiber, a round-trip signal transmission is established at both ends of the transmission link, so that when a polarization state change event occurs at a point on the transmission link of the monitoring area arranged in the second direction, 2M polarization state changes are generated in the optical signal, where M is the sequence number of the monitoring area arranged in the second direction. Extract the filter coefficients to calculate the Stokes vector of the current optical signal. Based on the changes in the time-domain waveform of the Stokes vector, obtain the occurrence time of the polarization state change to determine the location of the intrusion point in the monitoring area. The monitoring area is determined by analyzing the changes in the time-domain waveform based on the Stokes vector, acquiring the occurrence time of polarization state changes, and thus identifying the location of intrusion points within the monitoring area. This includes: When the monitoring area is arranged in the first direction, and the time-domain waveform of the Stokes vector shows three fluctuations, the occurrence of the three polarization state changes is recorded as follows: T 1. T 2 and T 3; According to the formula: , and To determine the location of the intrusion point, in the transmission link, A is the input point, B is the output point, and C is the intrusion point. L AC It is the distance between AC. L BC It is the distance between B and C. L AB AB is the distance between A and B, and V is the transmission rate of the optical signal in the optical fiber. The first direction is the transmission direction of the optical signal, and the second direction is a direction perpendicular to the transmission direction.

6. The sensing and positioning system based on coherent optical communication as described in claim 5, characterized in that: The process of extracting filter coefficients in the monitoring area to calculate the Stokes vector of the current optical signal includes: Extract the coefficients of the filter's x-polarization or y-polarization, and calculate the components of the Stokes vector based on these coefficients.

7. The sensing and positioning system based on coherent optical communication as described in claim 6, characterized in that, When extracting the coefficients of the filter's x-polarization: According to the formula: , Calculate the coefficients of the filter's x-polarization { , }, where L is the filter length; According to the formula: , , and To obtain the Stokes vector ,in These are the four components of the Stokes vector.

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