A two-way communication and sensing integrated system and a polarization state disturbance positioning method thereof

Abstract

The application provides a bidirectional communication and sensing integrated system, aiming at giving consideration to communication and realizing sensing function, integrating communication and sensing together, and realizing communication and sensing integration; based on the system, the application also provides a polarization state disturbance positioning method, at a transmitting end, time intervals between adjacent two frame heads of optical signals and time of the frame heads passing through an entire optical fiber link are same, only one frame head and signal exist in the optical fiber link at any time, so that polarization disturbance can be accurately monitored; a signal processor extracts disturbance information position through influence of polarization disturbance on polarization state of optical signals at a receiving end, and constructs equations by using bidirectional distance difference and synchronization of transmitting frame heads, and finally realizes accurate positioning of the polarization disturbance; the application positions polarization disturbance in the optical fiber link by using frame heads of bidirectional synchronous communication, has long detection distance, no measurement blind area and high precision, and has high sensitivity and does not need multiple detections of the receiving end for superposition.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical fiber communication and optical fiber sensing technology, and more particularly to a bidirectional sensing integrated system and a polarization state disturbance positioning method thereof. BACKGROUND

[0002] Optical fiber sensors have been widely used in high-voltage power cable, bridge structure health monitoring, airport perimeter security system and other fields due to their advantages of anti-electromagnetic interference, long-distance detection, etc. Based on discrete sensor elements such as optical fiber Bragg gratings or backscattering processes in optical fibers, various external environmental parameters around the optical fiber can be monitored, including temperature, strain, vibration, etc. However, the deployment cost of professional optical fiber sensor systems is high and cannot be ignored, and the requirements of the system for special devices or optical fibers also restrict the further popularization and use of optical fiber sensors. In the past three decades, with the rapid construction of optical fiber communication systems, millions of kilometers of optical fibers have been deployed in land and submarine environments. The additional sensor function based on optical communication cables has attracted more and more attention from telecom operators to provide additional business and revenue sources.

[0003] Compared with traditional optical fiber sensor systems, integrated communication sensing systems are based on deployed optical fiber networks. Thanks to the global optical fiber communication network, the sensing function can be extended not only to densely populated cities but also to wild areas. Inserting a sensor channel into the existing network is a feasible solution, however, the telecom network may need to modify the optical architecture to implement the sensing function, and additional devices need to be added, which increases the implementation cost. SUMMARY

[0004] In order to overcome the defects of the prior art that cannot balance optical fiber communication and sensing, and it is difficult and costly to add sensors in the field of communication and power, the present application provides a bidirectional sensing integrated system and a polarization state disturbance positioning method thereof, which can realize sensing function while balancing optical fiber communication, integrates communication and sensing together, and realizes sensing integration.

[0005] To solve the above technical problems, the technical solutions of the present application are as follows:

[0006] A bidirectional sensing integrated system, comprising a first optical fiber link and a second optical fiber link for transmitting optical signals in forward and reverse directions respectively, and a signal processor;

[0007] The first optical fiber link comprises a first transmitting end, a first optical fiber and a first receiving end connected in sequence; the second optical fiber link comprises a second transmitting end, a second optical fiber and a second receiving end connected in sequence; the first receiving end and the second receiving end are electrically connected with the signal processor respectively;

[0008] There is only one frame header and optical signal at any moment in the first and second optical fiber links;

[0009] The signal processor is used for detecting two adjacent frame headers carrying polarization disturbance information in the two optical signals in bidirectional transmission, obtaining distance difference between each frame header and the disturbance point in bidirectional transmission, and detecting the position of the polarization disturbance point according to the distance difference.

[0010] Preferably, the implementation of the first and second optical fiber links at any moment is that there is only one frame header and optical signal.

[0011] For the first and second optical fiber links, the time interval ΔT between the adjacent two frame headers of the optical signal and the time Δτ of the frame header passing through the optical fiber link are the same.

[0012] Preferably, the first and second optical fiber links have the same length, and the refractive indexes of the first and second optical fibers are the same.

[0013] Preferably, the time interval ΔT between the adjacent two frame headers of the optical signal and the time Δτ of the frame header passing through the optical fiber link satisfy the following relationship:

[0014]

[0015] Wherein, n represents the refractive index of the optical fiber, L represents the length of the optical fiber link, and c represents the speed of light in vacuum.

[0016] Preferably, the first and second optical fiber links are optical fiber links in the overhead ground wire composite optical cable OPGW.

[0017] The polarization disturbance information is specifically the change of the polarization state of the optical signal caused by lightning strike.

[0018] The application also provides a polarization state disturbance positioning method based on the bidirectional sensing integrated system, which is based on the bidirectional sensing integrated system and includes the following steps:

[0019] The first transmitting end sends the first polarized optical signal with inserted frame header into the first optical fiber for forward transmission, and the second transmitting end sends the second polarized optical signal with inserted frame header into the second optical fiber for reverse transmission; the first receiving end and the second receiving end receive the first polarized optical signal and the second polarized optical signal respectively, and convert them into the first electrical signal and the second electrical signal respectively for transmission to the signal processor.

[0020] When the first and second optical fiber links encounter a polarization disturbance event, the polarization states of the first and second polarized optical signals change, and the first and second polarized optical signals carry polarization disturbance information and are transmitted into the first and second receiving ends respectively.

[0021] The signal processor finds two adjacent frames of heads carrying polarization disturbance information by a preset digital signal processing algorithm for the first and second polarization optical signals respectively, and calculates the distance difference between the forward and reverse frames of heads and the disturbance point respectively to obtain bidirectional distance differences.

[0022] The polarization disturbance point position is calculated by using the bidirectional distance differences, so as to realize polarization disturbance positioning.

[0023] Preferably, the digital signal processing algorithm is specifically:

[0024] The distance difference between the forward and reverse frames of heads and the disturbance point is calculated according to the following formula for the first and second polarization optical signals respectively:

[0025]

[0026] Wherein, x represents the distance between the polarization disturbance point and the frame of head in the optical fiber link when the disturbance occurs, L represents the length of the optical fiber link, Δt represents the time difference between the time when the disturbance occurs and the time when the frame of head appears, and ΔT represents the time interval between the adjacent two frames of heads.

[0027] Preferably, the polarization disturbance point position is calculated by using the bidirectional distance differences, so as to realize polarization disturbance positioning.

[0028] In the forward transmission, the distance difference between the polarization disturbance point and the forward frame of head in the first optical fiber link when the disturbance occurs is In the reverse transmission, the distance difference between the polarization disturbance point and the reverse frame of head in the second optical fiber link when the disturbance occurs is

[0029] When the polarization disturbance occurs, the distance from the forward frame of head to the first transmitting end and the distance from the reverse frame of head to the second transmitting end are both ΔL.

[0030] The following equation is constructed:

[0031] L=x1+x2+2ΔL

[0032] Solving the equation, the distance from the polarization disturbance point to the first transmitting end is The distance from the polarization disturbance point to the second transmitting end is

[0033] Preferably, the signal processor detects the polarization state variation of the optical signal in real time according to Malus law, and specifically:

[0034] I=I0cos 2 (θ F )

[0035] Wherein, I is the light intensity of the optical signal received by the receiving end; I0 is the light intensity of the optical signal emitted by the transmitting end; θ FTo bias state rotation angle.

[0036] The application further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by the signal processor to realize the steps in the method.

[0037] Compared with the prior art, the beneficial effects of the technical scheme of the application are:

[0038] The application provides a bidirectional sensing integrated system, aiming to realize sensing function while considering communication, integrate communication and sensing together, realize sensing integration, and solve the problems of difficulty and high cost of adding sensors in the fields of communication and power.

[0039] In addition, based on the bidirectional sensing integrated system, the application further provides a polarization state disturbance positioning method, in the transmitting end, the time interval between the adjacent two frame headers of the optical signal and the time of the frame header passing through the whole optical fiber link are the same, so that only one frame header and signal exist in the optical fiber link at any moment, and thus the polarization disturbance can be accurately monitored; the signal processor extracts the disturbance information position by the influence of the polarization disturbance on the power and phase of the signal light of the receiving end, and constructs an equation by using the bidirectional distance difference and the synchronization of the transmitting frame header, and finally realizes accurate positioning of the polarization disturbance.

[0040] The application uses the frame header of bidirectional synchronous communication to position the polarization disturbance in the optical fiber link, and compared with the traditional optical sensor method, the detection distance is long, there is no measurement blind area and the accuracy is high; compared with the traditional distributed optical time domain reflection method, the sensitivity is high and the receiving end does not need to perform multiple detections for superposition. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a structure diagram of a bidirectional sensing integrated system provided in embodiment 1.

[0042] Figure 2 It is a component structure diagram of a power overhead optical cable provided in embodiment 2.

[0043] Figure 3 It is a structure diagram of an optical unit provided in embodiment 2.

[0044] Figure 4 It is a Faraday effect schematic diagram provided in embodiment 2.

[0045] Figure 5 It is a schematic diagram of the polarization disturbance acting on the optical fiber link provided in embodiment 2.

[0046] Figure 6 It is a flow chart of a polarization state disturbance positioning method based on the bidirectional sensing integrated system provided in embodiment 3. DETAILED DESCRIPTION

[0047] The accompanying drawings are included to provide a further understanding of the present application and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0048] To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product.

[0049] It is understandable for those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0050] The technical solutions of the present application will be further described below in combination with the drawings and embodiments.

[0051] Embodiment 1

[0052] As shown in the drawings, the present embodiment provides a bidirectional sensing integrated system, which includes a first optical fiber link and a second optical fiber link for transmitting optical signals in forward and reverse directions respectively, and a signal processor. Figure 1 The first optical fiber link includes a first transmitting end, a first optical fiber and a first receiving end connected in sequence; the second optical fiber link includes a second transmitting end, a second optical fiber and a second receiving end connected in sequence; the first receiving end and the second receiving end are electrically connected with the signal processor respectively.

[0053] There is only one frame header and an optical signal at any moment in the first optical fiber link and the second optical fiber link.

[0054] The signal processor is used to detect two adjacent frame headers carrying polarization disturbance information in two optical signals in bidirectional transmission, and obtain the distance difference between each frame header and the disturbance point in bidirectional transmission, and detect the position of the polarization disturbance point according to the distance difference.

[0055] In the specific implementation process, the present system directly realizes sensing based on communication signals, and the principle is that in coherent receiving digital signal processing, the polarization state can be extracted from the polarization multiplexing signal, and due to the sensitivity between the fiber vibration caused by the polarization state environmental disturbance, the characteristic fluctuation of the polarization state can be defined to identify different vibration events.

[0056] The process of realizing communication by using the present system is as follows:

[0057] The first transmitting end sends a first polarized optical signal with a frame header into the first optical fiber for forward transmission; at the same time, the second transmitting end sends a second polarized optical signal with a frame header into the second optical fiber for reverse transmission.

[0058] The first receiving end and the second receiving end respectively receive the first polarized optical signal and the second polarized optical signal, and respectively convert them into a first electrical signal and a second electrical signal for transmission to the signal processor.

[0059] ​

[0060] The above-mentioned bidirectional synchronous transceiving process is repeated to realize fiber communication.

[0061] The process of realizing polarization state disturbance positioning (i.e., sensing) by using the system is as follows:

[0062] When the first optical fiber link and the second optical fiber link encounter a polarization disturbance event, the polarization states of the first and second polarization optical signals change, and the first and second polarization optical signals carrying the polarization disturbance information are transmitted into the first and second receiving ends, respectively;

[0063] In the signal processor, for the first and second polarization optical signals, the adjacent two frames of heads carrying the polarization disturbance information are found by using a preset digital signal processing algorithm, respectively, and the distance difference between the forward and reverse frames of heads and the disturbance point is calculated, respectively, to obtain the bidirectional distance difference.

[0064] The polarization disturbance point position is calculated by using the bidirectional distance difference, so as to realize polarization disturbance positioning.

[0065] The system can realize sensing function while taking into account communication, and compared with the traditional optical fiber sensor scheme, the system has the advantages of not needing to increase other additional devices, reducing the implementation cost; and can realize long-distance and high-sensitivity polarization disturbance positioning, integrates communication and sensing together, and realizes communication-sensing integration.

[0066] Embodiment 2

[0067] The embodiment provides a bidirectional communication-sensing integrated system, which comprises a first optical fiber link and a second optical fiber link for transmitting optical signals in forward and reverse directions, respectively, and a signal processor.

[0068] The first optical fiber link comprises a first transmitting end, a first optical fiber and a first receiving end connected in sequence; the second optical fiber link comprises a second transmitting end, a second optical fiber and a second receiving end connected in sequence; and the first receiving end and the second receiving end are electrically connected with the signal processor.

[0069] There is only one frame of head and optical signal at any moment in the first optical fiber link and the second optical fiber link.

[0070] The signal processor is used for detecting two adjacent frames of heads carrying polarization disturbance information in the two optical signals in bidirectional transmission, obtaining the distance difference between each frame of head and the disturbance point in bidirectional transmission, and detecting the polarization disturbance point position according to the distance difference.

[0071] The implementation mode that there is only one frame of head and optical signal at any moment in the first optical fiber link and the second optical fiber link is as follows:

[0072] The time interval ΔT between adjacent two frame headers of the optical signal and the time Δτ of the frame header passing through the optical fiber link are the same for the first optical fiber link and the second optical fiber link;

[0073] The first optical fiber link and the second optical fiber link have the same length, and the first optical fiber and the second optical fiber have the same refractive index;

[0074] The time interval ΔT between adjacent two frame headers of the optical signal and the time Δτ of the frame header passing through the optical fiber link satisfy the following relationship:

[0075]

[0076] Wherein, n represents the refractive index of the optical fiber, L represents the length of the optical fiber link, and c represents the speed of light in vacuum;

[0077] The first optical fiber link and the second optical fiber link are both optical fiber links in an overhead ground wire composite optical cable OPGW;

[0078] The polarization disturbance information is specifically a change in the polarization state of the optical signal caused by lightning.

[0079] In the specific implementation process, the working process of the system is illustrated by taking the polarization disturbance encountered in the power field as an example;

[0080] When the overhead ground wire composite optical cable (OPGW) encounters extreme weather such as a thunderstorm season, on the one hand, the power 100G OTN backbone network part link will occur multiple times. Flashing off, the reason for this abnormality is that the Faraday optical rotation effect caused by lightning causes the polarization state of the optical signal in the overhead optical cable to fluctuate rapidly, thereby causing the 100G OTN device to have errors; on the other hand, the high energy caused by lightning current can cause the OPGW to break, thereby affecting power production, so it is necessary to locate the polarization state disturbance;

[0081] The structure and composition of the overhead optical cable are introduced by taking the OPGW as an example; as shown in Figure 2 The structure of the OPGW mainly comprises an optical unit and a ground wire unit; as shown in Figure 3 The optical unit is composed of a protective tube made of stainless steel or aluminum and an optical fiber therein, and the optical fiber generally has excess length (i.e., the length of the optical fiber is slightly longer than that of the protective tube) to avoid the protective tube being gradually stretched mechanically during long-term operation, causing the optical fiber to be stressed and broken, and the protective tube and the optical fiber are filled with fiber paste to play a role in waterproofing and the like; the ground wire unit is composed of aluminum-clad steel wires spirally twisted, and the aluminum-clad steel wires are filled with oil paste, and the function of the aluminum-clad steel wires is mainly to serve as a conductor for grounding protection and attract lightning to avoid direct lightning strikes on the power phase line;

[0082] Under the action of the magnetic field, the originally non-rotatory substance also produces rotatory, and can make the light vector rotate, that is, when the light passes through the medium without rotatory under the action of the magnetic field, the vibration plane of the light will rotate, which is called Faraday effect, as shown in formula (1) ; the angle θ of the light vector rotation is proportional to the distance of the light passing through the medium and the magnetic induction intensity B, and the calculation formula is as follows: Figure 4

[0083] θ=VBL B

[0084] Wherein, V is the Verdet constant, which is a characteristic constant of the substance and determines the magneto-optical properties of the material; the positive and negative of the Verdet constant depends on the type of the material; when the light passes through the material, if the Verdet constant is positive, the light vector will rotate clockwise; if the Verdet constant is negative, the light vector will rotate counterclockwise; for the standard single-mode optical fiber, the Verdet constant at 1550 nm wavelength at normal temperature is about 0.53 rad / (T·m);

[0085] The power overhead optical cable struck by lightning can be approximated by a powered solenoid model, and the relationship expression of the magnetic field formed by the lightning current near the optical cable is as follows:

[0086] B=μNI

[0087] According to the Faraday rotatory effect, the polarization state rotation angle of the optical signal caused by lightning is obtained by Malus law as follows:

[0088] I=I0cos 2 (θ F )

[0089] Wherein, I is the light intensity of the optical signal received by the receiving end; I0 is the light intensity of the optical signal emitted by the transmitting end; θ F is the polarization state rotation angle;

[0090] The optical signal reaches the receiving end, is converted into an electrical signal, and is transmitted to a signal processor, and the processor calculates the polarization state change size according to Malus law;

[0091] At the transmitting end, the time interval between the adjacent two frames of the signal light and the time of the frame passing through the whole optical fiber link are the same, so that the time interval ΔT between the adjacent two frames of the signal light and the time Δτ of the frame passing through the whole optical fiber link are the same, Wherein, n represents the refractive index of the optical fiber, L represents the length of the optical fiber link, and c represents the speed of light in vacuum. That is, only one frame of frame and signal exists in the optical fiber link at any time, so that the polarization disturbance can be accurately monitored;

[0092] ​In normal circumstances, the system is in optical fiber communication mode, in which the first transmitting end sends the first polarized light signal with inserted frame header into the first optical fiber for forward transmission; at the same time, the second transmitting end sends the second polarized light signal with inserted frame header into the second optical fiber for reverse transmission; the first receiving end and the second receiving end receive the first polarized light signal and the second polarized light signal respectively, and convert them into the first electrical signal and the second electrical signal respectively for transmission to the signal processor;

[0093] When the optical fiber link of the OPGW encounters lightning strike and the optical signal is disturbed in polarization state, the optical signal carrying the polarization rotation information is extracted by the digital signal processing algorithm at the receiving end, and the relative position of the rotation in the adjacent two frames is accurately located.

[0094] As shown in Figure 5 When the polarization state of the forward and reverse signal light changes, the signal light carrying the polarization rotation information is transmitted into the two receiving ends in turn; in the forward transmission, the adjacent two frames carrying the polarization rotation information are found by signal processing, and the distance difference between the forward frame header and the lightning strike point is determined by the corresponding proportion; in the reverse transmission, the adjacent two frames carrying the polarization disturbance information are found by signal processing, and the distance difference between the reverse frame header and the lightning strike point is determined by the corresponding proportion; the disturbance information position is extracted by the influence of the polarization rotation on the power of the receiving end signal light, that is Where x represents the distance between the lightning strike point and the frame header in the optical fiber link when lightning strikes, L represents the length of the optical fiber link, Δt represents the time difference between the disturbance time and the time when the frame header appears, and ΔT represents the time difference between the adjacent two frame headers.

[0095] The bidirectional distance difference and the synchronization of the transmitting frame header are used to construct equations, and the lightning strike point position is solved, so as to realize lightning strike positioning; in the forward transmission, the distance difference between the lightning strike point and the forward frame header in the optical fiber link is In the reverse transmission, the distance difference between the lightning strike point and the reverse frame header in the optical fiber link is Due to the synchronization of the transmitting frame header, when lightning strikes, the distance between the forward frame header and the first transmitting end and the distance between the reverse frame header and the second transmitting end are both ΔL; at this time, the equation L=x1+x2+2ΔL can be constructed, and the distance from the lightning strike point to the first transmitting end is solved as The distance from the lightning strike point to the second transmitting end is

[0096] The system can realize sensing function while taking into account communication, and compared with the traditional optical fiber sensor scheme, it has the advantages of not needing to increase other additional devices, reducing the implementation cost; and it can realize long-distance, high-sensitivity polarization disturbance positioning, integrates communication and sensing together, and realizes the integration of communication and sensing.

[0097] Example 3

[0098] As Figure 6 shown, the embodiment provides a polarization state disturbance positioning method based on a bidirectional sensing integrated system, based on the bidirectional sensing integrated system described in embodiment 1 or 2, comprising the following steps:

[0099] S1: the first transmitting end transmits the first polarized optical signal with inserted frame header into the first optical fiber for forward transmission; at the same time, the second transmitting end transmits the second polarized optical signal with inserted frame header into the second optical fiber for reverse transmission;

[0100] S2: the first receiving end and the second receiving end respectively receive the first polarized optical signal and the second polarized optical signal, and respectively convert them into first electrical signal and second electrical signal for transmission to the signal processor;

[0101] S3: when the first optical fiber link and the second optical fiber link encounter a polarization disturbance event, the polarization states of the first and second polarized optical signals change, and the first and second polarized optical signals carrying polarization disturbance information are transmitted into the first and second receiving ends respectively;

[0102] S4: in the signal processor, for the first and second polarized optical signals, the adjacent two frame headers carrying polarization disturbance information are found respectively through a preset digital signal processing algorithm, and the distance difference between the forward frame header and the reverse frame header and the disturbance point is calculated respectively to obtain the bidirectional distance difference;

[0103] S5: the polarization disturbance point position is calculated using the bidirectional distance difference, so as to realize polarization disturbance positioning.

[0104] In the specific implementation process, the first transmitting end transmits the first polarized optical signal with inserted frame header into the first optical fiber for forward transmission; at the same time, the second transmitting end transmits the second polarized optical signal with inserted frame header into the second optical fiber for reverse transmission;

[0105] The first receiving end and the second receiving end respectively receive the first polarized optical signal and the second polarized optical signal, and respectively convert them into first electrical signal and second electrical signal for transmission to the signal processor;

[0106] The above-mentioned bidirectional synchronous transceiving process is repeated to realize optical fiber communication;

[0107] When the first optical fiber link and the second optical fiber link encounter a polarization disturbance event, the polarization states of the first and second polarized optical signals change, and the first and second polarized optical signals carrying polarization disturbance information are transmitted into the first and second receiving ends respectively;

[0108] In the signal processor, for the first and second polarized optical signals, the adjacent two frame headers carrying polarization disturbance information are found respectively through a preset digital signal processing algorithm, and the distance difference between the forward frame header and the reverse frame header and the disturbance point is calculated respectively to obtain the bidirectional distance difference;

[0109] The polarization disturbance point position is calculated by using the bidirectional distance difference, so that the polarization disturbance positioning is realized.

[0110] The method uses the frame header of bidirectional synchronous communication to locate the polarization disturbance in the optical fiber link, compared with the traditional optical sensor method, the detection distance is long, there is no measurement blind area and the precision is high; compared with the traditional distributed optical time domain reflection method, the sensitivity is high and the receiving end does not need to detect multiple times for superposition.

[0111] The same or similar reference signs correspond to the same or similar components;

[0112] The terms describing the positional relationship in the drawings are only used for example illustration, and cannot be understood as the limitation of the patent;

[0113] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not the limitation of the embodiments of the present application. For the ordinary skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A two-way communication and sensing integrated system, characterized in that, The application relates to a signal processing device for a bidirectional optical transmission system, comprising a first optical fiber link and a second optical fiber link for transmitting optical signals in forward and reverse directions respectively, and a signal processor. The first optical fiber link comprises a first transmitting end, a first optical fiber and a first receiving end connected in sequence; the second optical fiber link comprises a second transmitting end, a second optical fiber and a second receiving end connected in sequence; the first receiving end and the second receiving end are electrically connected to the signal processor respectively. The first optical fiber link and the second optical fiber link only have one frame header and one optical signal at any moment, and the implementation manner is that: for the first optical fiber link and the second optical fiber link, the time interval Δ between the adjacent two frame headers of the optical signal is set T The same as the time Δ of the frame header passing through the optical fiber link The signal processor is used for detecting two adjacent frame headers carrying polarization disturbance information in two optical signals in bidirectional transmission, obtaining distance differences between each frame header and a disturbance point in bidirectional transmission, and detecting the position of the polarization disturbance point according to the distance differences, wherein the distance difference between the frame header and the disturbance point is calculated according to the following formula: . The first optical fiber link and the second optical fiber link have the same length, and the first optical fiber and the second optical fiber have the same refractive index. wherein, x represents the distance between the polarization disturbance point and the frame header in the fiber link when the disturbance occurs, L represents the length of the fiber link, Δ t represents the time difference between the time when the disturbance occurs and the time when the frame header appears, Δ T represents the time interval between two adjacent frame headers.

2. The integrated system of claim 1, wherein, The first optical fiber link and the second optical fiber link are both optical fiber links in an overhead ground wire composite optical cable (OPGW).

3. The integrated two-way communication and sensing system of claim 2, wherein, the time interval Δ between the two adjacent frame headers of the optical signal T the time Δ of the frame header passing through the optical fiber link The polarization disturbance information is specifically a change in the polarization state of the optical signal caused by lightning strike. satisfies the following relationship: wherein, n denotes the optical fiber refractive index, L denotes the optical fiber link length, c denotes the speed of light in vacuum.

4. The system according to any one of claims 1 to 3, wherein the system is a two-way communication integrated system. The application relates to a signal processing device for a bidirectional optical transmission system, comprising a first optical fiber link and a second optical fiber link for transmitting optical signals in forward and reverse directions respectively, and a signal processor. The first transmitting end emits a first polarized optical signal with a frame header into the first optical fiber for forward transmission; meanwhile, the second transmitting end emits a second polarized optical signal with a frame header into the second optical fiber for reverse transmission; the first receiving end and the second receiving end receive the first polarized optical signal and the second polarized optical signal respectively and convert them into a first electrical signal and a second electrical signal respectively for transmission to the signal processor.

5. A polarization state disturbance positioning method based on a bidirectional communication and sensing integrated system, based on the bidirectional communication and sensing integrated system in any one of claims 1-4, characterized in that, When the first optical fiber link and the second optical fiber link encounter a polarization disturbance event, the polarization states of the first and second polarized optical signals change, and the first and second polarized optical signals carry polarization disturbance information and are transmitted into the first and second receiving ends respectively. In the signal processor, for the first and second polarized optical signals, adjacent two frame headers carrying polarization disturbance information are found respectively through a preset digital signal processing algorithm, and distance differences between forward frame headers and reverse frame headers and disturbance points are calculated respectively to obtain bidirectional distance differences. For the first optical fiber link and the second optical fiber link, the time interval Δ between adjacent two frame headers of the optical signal is set T and the time Δ of the frame header passing through the optical fiber link The digital signal processing algorithm is specifically: is the same; For the first and second polarized optical signals, the distance differences between forward frame headers and reverse frame headers and disturbance points are calculated according to the following formula respectively: The polarization disturbance point position is calculated by using the bidirectional distance differences, so that polarization disturbance positioning is realized. The polarization disturbance point position is calculated by using the bidirectional distance differences, so that polarization disturbance positioning is realized. The following equation is constructed: wherein, x represents the distance between the polarization disturbance point and the frame header in the fiber link when the disturbance occurs, L represents the length of the fiber link, Δ t represents the time difference between the time when the disturbance occurs and the time when the frame header appears, Δ T represents the time interval between two adjacent frame headers; The signal processor detects the change in the polarization state of the optical signal in real time according to Malus' law, and the change is specifically:

6. The polarization state perturbation locating method based on the bidirectional communication integration system according to claim 5, characterized in that, The computer program is executed by the signal processor to realize the steps in the method of any one of claims 5-7. In the forward transmission, the distance difference between the polarization disturbance point and the forward frame header in the first optical fiber link when the disturbance occurs is ; in the reverse transmission, the distance difference between the polarization disturbance point and the reverse frame header in the second optical fiber link when the disturbance occurs is ; When the polarization disturbance occurs, the distance from the forward frame header to the first transmitting end and the distance from the reverse frame header to the second transmitting end are both Δ L ; ​ Solving the equation, the distance from the polarization disturbance point to the first transmitting end is , and the distance from the polarization disturbance point to the second transmitting end is .

7. The polarization state perturbation locating method based on the bidirectional communication integrated system according to any one of claims 5-6, characterized in that, ​ wherein, I is the light intensity of the optical signal received by the receiving end; I 0 is the light intensity of the optical signal emitted by the transmitting end; is the rotation angle of the bias state.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that ​

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