Multi-system sensing fusion method based on communication line

Abstract

The application provides a multi-system sensing fusion method based on a communication line, relates to the technical field of optical fiber communication and sensing fusion, and comprises the following steps: determining communication equipment and signal light wavelengths at both ends of a communication optical fiber line, and determining at least one set of distributed optical fiber sensing systems to be fused and sensing light wavelengths; selecting at least one group of three-port optical fiber filters, setting center wavelengths of the three-port optical fiber filters according to the communication equipment signal light wavelengths and the sensing light wavelengths, and making the communication signal light and the sensing signal light wavelengths not overlap each other to ensure signal isolation; and the application adopts a three-port filter cascaded coupling mode, does not need to make a common modulation transformation at the equipment end, does not need to make customized adjustment on the existing communication equipment and the distributed optical fiber sensing system, realizes plug and play, can be directly compatible with the built distributed independent system, greatly reduces the transformation cost and implementation difficulty of the sensing fusion, and expands the application range of the technology.

Description

Technical Field

[0001] This invention relates to the field of optical fiber communication and sensing fusion technology, and in particular to a multi-system sensing fusion method based on communication lines. Background Technology

[0002] With the rapid advancement of information technology construction, the demand for information transmission continues to grow, leading telecommunications operators to lay a large number of widely distributed optical fiber communication cables in complex environments. To monitor situations such as cable damage, geological changes, and pipeline leaks, distributed optical fiber sensing systems are widely used, enabling the construction of large-scale sensing networks based on existing optical fiber communication networks. Currently, distributed optical fiber sensing systems mostly use dark optical fibers within communication cables for signal transmission. Multiple sensing systems require multiple dark optical fibers, resulting in significant waste of optical fiber resources. Therefore, sensor fusion has become a key direction for improving the utilization rate of optical fiber resources. Existing sensor fusion technologies mainly employ two implementation schemes: one is to achieve co-fiber transmission of communication and sensing signals through a shared light source and co-modulation; the other is to couple signals using optical fiber couplers and amplify the fused signal using optical amplifiers, while employing multi-core optical fibers and dense frequency division multiplexing technology to reduce crosstalk.

[0003] Existing solutions require fusion at the device end or rely on optical amplifiers, which are incompatible with existing, decentralized, and independent fiber optic sensing systems and communication equipment, resulting in poor adaptability. The use of optical amplifiers requires additional power supply and new equipment, increasing application costs and inconvenience. Furthermore, some solutions have high customization requirements for sensing systems, making them unsuitable for conventional sensing systems. Existing solutions mostly only support unidirectional signal transmission, which cannot meet the needs of round-trip signal transmission scenarios, and are difficult to adapt to the fusion requirements of multiple sensing systems coexisting and communication equipment with arbitrary wavelengths. Signal isolation and scenario adaptability are significantly limited. Therefore, this invention proposes a multi-system sensing fusion method based on communication lines to solve the problems existing in the prior art. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a multi-system sensing fusion method based on communication lines. This method employs a cascaded coupling approach with three-port filters, eliminating the need for co-modulation modifications at the equipment end or customized adjustments to existing communication equipment and distributed fiber optic sensing systems. It achieves plug-and-play functionality, directly compatible with existing distributed independent systems, significantly reducing the modification costs and implementation difficulties of sensing fusion, and expanding the application scope of the technology.

[0005] To achieve the objectives of this invention, the invention is implemented through the following technical solution: a multi-system sensing fusion method based on communication lines, comprising the following steps:

[0006] S1: Determine the communication equipment and its signal wavelength at both ends of the communication fiber optic line site, and determine at least one distributed fiber optic sensing system to be integrated and its sensing wavelength.

[0007] S2: Select at least one set of three-port fiber optic filters, and set the center wavelength of each three-port fiber optic filter according to the wavelength of the communication equipment signal light and the wavelength of the sensing light, so that the wavelengths of the communication signal light and the sensing signal light do not overlap, thus ensuring signal isolation.

[0008] S3: Connect the communication equipment, distributed optical fiber sensing system and three-port optical fiber filter in a topology. Utilize the characteristics of the Com port, Ref port and filter port of the three-port filter to achieve passive coupling between the communication signal light and the sensing signal light.

[0009] S4: Connect the coupled signal light to the communication optical fiber to realize the co-fiber transmission between the communication equipment and the distributed optical fiber sensing system. The backscattered signal generated by the sensing signal light in the communication optical fiber returns to the corresponding distributed optical fiber sensing system along the original path.

[0010] A further improvement is made in that: the distributed optical fiber sensing system is a single-sensor unidirectional system, and the topology connection in S3 is specifically as follows: two sets of three-port optical fiber filters are selected, and filter 1 and filter 2 are respectively set to have a center wavelength that matches the signal light wavelength of the communication equipment of the two stations; the output light of the communication equipment of station 1 is connected to the Com port of filter 2, the wavelength-matched communication signal light is output from the Ref port of filter 2, connected to the filter port of filter 1, and then output from the Com port of filter 1 to the communication optical fiber; the communication signal light transmitted in the communication optical fiber is connected to the Com port of filter 2 of station 2, output from its Ref port to the Com port of filter 1, and then output from the filter port of filter 1 to the communication equipment of station 2; the output light of the optical fiber sensing device of the single-sensor unidirectional system is connected to the Ref port of filter 1 of station 2, output from its Com port to the Ref port of filter 2 of station 2, and then output from its Com port to the communication optical fiber, and the backscattered signal returns to the optical fiber sensing device along the original path.

[0011] A further improvement is made in that: the distributed optical fiber sensing system is a single-sensor round-trip system, and the topology connection in S3 is specifically as follows: two sets of three-port optical fiber filters are selected, and filter 1 and filter 2 are respectively set to have a center wavelength consistent with the signal light wavelength of the communication equipment of the two stations; the output light of the communication equipment of station 1 is connected to the Com port of filter 2, and the wavelength-matched communication signal light is output from the Ref port of filter 2, connected to the filter port of filter 1, and then output from the Com port of filter 1 to the communication optical fiber; the communication signal light transmitted in the communication optical fiber is connected to the Com port of filter 2 of station 2, output from its Ref port to the Com port of filter 1, and then output from the filter port of filter 1 to the communication equipment of station 2; the output light of the communication equipment of station 2 is connected to the Com port of filter 1, and the wavelength-matched communication signal light is connected from the filter... The output of the Ref port of device 1 is connected to the filter port of filter 2, and then output from the Com port of filter 2 to the communication optical fiber; the communication signal light transmitted in the communication optical fiber is connected to the Com port of filter 1 of station 1, and output from its Ref port to the Com port of filter 2, and then output from the filter port of filter 2 to the communication equipment of station 1; the output light of the front end of the fiber optic sensing equipment of the single-sensor round-trip system is connected to the Ref port of filter 1 of station 2, and after being coupled by filter 1 and filter 2, it is connected to the communication optical fiber, and the backscattered signal returns along the original path; the output light of the back end of the fiber optic sensing equipment is connected to the Ref port of filter 2 of station 1, and after being coupled by filter 2 and filter 1, it is connected to the communication optical fiber, and after being coupled by filter 2 and filter 1 of station 2, the detection of the communication optical fiber or the amplification of the signal light of the front end of the fiber optic sensing equipment is realized.

[0012] Further improvements are made in the following ways: the distributed optical fiber sensing system is a multi-sensor unidirectional system; in step S2, two sets of three-port optical fiber filters matching the wavelength of the communication equipment are selected, as well as at least two sets of three-port optical fiber filters matching the wavelength of each sensing system; in step S3, the topology connection is as follows: the output light of the communication equipment at station 1 is connected to the Com port of the corresponding filter, the wavelength-matched communication signal light is output from the Ref port of the filter, connected to the filter port of another set of corresponding filters, and then output from the Com port of the filter to the communication optical fiber; the communication signal light transmitted through the communication optical fiber is connected to the Com port of the corresponding filter at station 2, output from its Ref port to the Com port of another set of corresponding filters, and then output from the filter port of the filter to the communication equipment at station 2; The communication equipment output light of site 2 is connected to the Com port of the corresponding filter. The wavelength-matched communication signal light is output from the Ref port of the filter, connected to the filter port of another set of corresponding filters, and then output from the Com port of the filter to the communication optical fiber. The communication signal light transmitted through the communication optical fiber is connected to the Com port of the corresponding filter of site 1, output from its Ref port to the Com port of another set of corresponding filters, and then output from the filter port of the filter to the communication equipment of site 1. The output light of each fiber optic sensing device is connected to the filter port or Ref port of the filter of the corresponding wavelength, and after being coupled by multiple filters, it is connected to the communication optical fiber. The backscattered signal of each sensing signal returns to the corresponding fiber optic sensing device along its own path, and the sensing signals and communication signals do not interfere with each other.

[0013] Further improvements are made in the following ways: the distributed optical fiber sensing system is a multi-sensor round-trip system; in step S2, two sets of three-port optical fiber filters matching the wavelength of the communication equipment are selected, and at least two sets of three-port optical fiber filters matching the wavelength of each sensing system are also selected; in step S3, the topology connection is as follows: the output light of the communication equipment at station 1 is connected to the Com port of the corresponding filter; the wavelength-matched communication signal light is output from the Ref port of the filter, connected to the filter port of another set of corresponding filters, and then output from the Com port of the filter to the communication optical fiber; the communication signal light transmitted through the communication optical fiber is connected to the Com port of the corresponding filter at station 2, output from its Ref port to the Com port of another set of corresponding filters, and then output from the filter port of the filter to the communication equipment at station 2; the communication at station 2... The output light of the device is connected to the Com port of the corresponding filter. The wavelength-matched communication signal light is output from the Ref port of the filter, connected to the filter port of another set of corresponding filters, and then output from the Com port of the filter to the communication optical fiber. The communication signal light transmitted in the communication optical fiber is connected to the Com port of the corresponding filter of station 1, output from its Ref port to the Com port of another set of corresponding filters, and then output from the filter port of the filter to the communication equipment of station 1. The output light of the front end of each fiber optic sensing device is coupled to the communication optical fiber after being coupled by the corresponding filter, and the backscattered signal returns along the original path. The output light of the back end of each fiber optic sensing device is coupled to the communication optical fiber after being coupled by the corresponding filter in multiple stages, and then coupled by the far-end filter to realize the detection of the communication optical fiber or the amplification of the signal light of the front end of the corresponding sensing device.

[0014] Further improvements are made in the following ways: the communication device is an arbitrary wavelength communication device; in step S2, two sets of three-port fiber filters with center wavelengths of 1450nm and 1660nm are selected, and at least three sets of three-port fiber filters are matched with the wavelengths of each sensing system; in step S3, the topology connection is as follows: the output light of the two-site communication devices is coupled through multi-stage filters and then connected to the communication fiber to realize the transmission of arbitrary wavelength communication signals; the output light of the front end and back end of each fiber sensing device is coupled through corresponding filters through multi-stage coupling and then connected to the communication fiber; the backscattered signal of the sensing signal returns along its respective path, wherein the backscattered anti-Stokes light and backscattered Stokes light of the distributed fiber Raman sensing system DTS are coupled through corresponding filters and then returned to the DTS device.

[0015] The further improvement lies in the fact that the three-port fiber optic filter has a filtering bandwidth of 100GHz, an insertion loss of 0.8dB at the transmission end, and an insertion loss of 0.4dB at the reflection end.

[0016] A further improvement is that the distributed optical fiber sensing system includes one or more of the following: a distributed optical fiber vibration sensing system, a distributed optical fiber Brillouin optical time domain reflectometer, and a distributed optical fiber Raman sensing system (DTS); the back end of the optical fiber sensing device is an optical fiber amplifier or a distributed optical fiber sensing system.

[0017] Further improvements are made by introducing a Raman amplifier when the communication fiber is used for long-distance transmission. The Raman amplifier has a broadband gain effect on C-band light, which compensates for the insertion loss caused by fusion and amplifies the communication signal light. In distributed fiber optic sensing, a Raman amplifier is added for distances exceeding 50km. When the measurement distance is between 30 and 40km, a Raman amplifier is added to improve the signal-to-noise ratio or to compensate for additional line losses.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. This invention adopts a three-port filter cascade coupling method, which eliminates the need for co-modulation modification at the device end and customized adjustments to existing communication equipment and distributed fiber optic sensing systems. It achieves plug-and-play functionality and is directly compatible with existing distributed independent systems, significantly reducing the transformation cost and implementation difficulty of sensing fusion and expanding the application scope of the technology.

[0020] 2. This invention abandons the traditional active amplification approach and achieves signal coupling solely through the port characteristics of a three-port filter. It eliminates the need for additional power supply equipment such as optical amplifiers, which not only reduces equipment investment and operating costs but also avoids the inconvenience caused by additional power supply. Furthermore, it eliminates the need for custom-designed light sources for the sensing system and can be adapted to conventional distributed fiber optic sensing systems, further enhancing the practicality and versatility of the technology.

[0021] 3. This invention can achieve flexible adaptation between single and multiple sensors, and between one-way and round-trip transmission. It is also compatible with communication devices of any wavelength. Through topology matching of the filter, it ensures that signals do not interfere with each other when multiple wavelengths and multiple systems coexist. Even when Raman amplifiers are introduced for long-distance transmission, the signal-to-noise ratio of each system remains controllable, and the detection effect of the sensor signal is not substantially affected. This effectively improves the utilization rate of optical fiber resources and provides reliable technical support for large-scale sensing in fields such as communication networks, smart cities, and energy security. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the method for integrating a single-sensor unidirectional system with a communication device according to the present invention;

[0023] Figure 2 This is a schematic diagram of the spectrum of the light source of the communication device 1 (C36 wavelength) in the access system of the present invention after passing through the communication optical fiber.

[0024] Figure 3This is a schematic diagram of the spectrum of the light source (C35 wavelength) of the communication device 2 (communication fiber optic) in the access system of the present invention after passing through the communication optical fiber.

[0025] Figure 4 This is a schematic diagram of the distributed vibration sensing system detecting signals before the access system of the present invention;

[0026] Figure 5 This is a schematic diagram of the light source of the communication device 1 (C36 wavelength) before and after the access system of the present invention passing through the communication optical fiber;

[0027] Figure 6 This is a schematic diagram of the light source of the communication device 1 (C36 wavelength) before and after the access system of the present invention passing through the communication optical fiber;

[0028] Figure 7 This is a schematic diagram of the detection signals of the distributed vibration sensing system before and after the access system of the present invention;

[0029] Figure 8 This is a schematic diagram of the method for integrating a single-sensor round-trip system with a communication device according to the present invention;

[0030] Figure 9 This is a schematic diagram of the method for integrating a multi-sensor unidirectional system with a communication device according to the present invention;

[0031] Figure 10 This is a schematic diagram of the multi-sensor round-trip system and communication device fusion method of the present invention;

[0032] Figure 11 This is a schematic diagram of the method for integrating the multi-sensor round-trip system with an arbitrary wavelength communication device according to the present invention. Detailed Implementation

[0033] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0034] Example 1

[0035] according to Figure 1 As shown, this embodiment proposes a multi-system sensing fusion method based on communication lines, which is suitable for sensing fusion scenarios between single-sensor unidirectional systems and communication devices:

[0036] System parameters are determined as follows: Communication fiber optic line sites 1 and 2 are equipped with communication equipment 1 and communication equipment 2, respectively. The signal light wavelength λ1 of communication equipment 1 is C36 (ITU wavelength table, 1548.51nm), and the output light intensity is 13.1dBm; the signal light wavelength λ2 of communication equipment 2 is C35 (ITU wavelength table, 1549.32nm), and the output light intensity is 12.05dBm; the distributed fiber optic sensing system to be integrated is a distributed fiber optic vibration sensing system, with a sensing light wavelength λ3 of C18 (ITU wavelength table, 1563.05nm); the length of the communication fiber optic cable is approximately 70km.

[0037] Filter selection: Two sets of three-port fiber optic filters were selected. Filter 1 has a center wavelength of C36 and filter 2 has a center wavelength of C35. Both filters have a bandwidth of 100GHz. The insertion loss at the transmission end is about 0.8dB and the insertion loss at the reflection end is about 0.4dB.

[0038] Topology connection: The output light of communication device 1 (site 1) enters the Com input terminal of filter 2. According to the characteristics of the three-port filter, the signal light with wavelength λ1 is output from the Ref port, enters the filter port of filter 1, and then is output from the Com port into the communication optical fiber. After the signal light λ1 is transmitted through the communication optical fiber, it enters from the Com port of filter 2 of site 2, is output from the Ref port into the Com port of filter 1 of site 2, is then output from the filter port into the filter port of filter 1 of site 2, and is output from the Com port into communication device 2, realizing bidirectional transmission of communication signals.

[0039] The output signal light λ3 of the fiber optic sensing device enters the Ref port of filter 1 at station 2, exits from the Com port and enters the Ref port of filter 2 at station 2, and then exits from the Com port and enters the communication fiber. The backscattered signal light generated by the signal light λ3 in the communication fiber has a wavelength near λ3 and returns to the fiber optic sensing device along the original path.

[0040] Verification data: Before accessing the converged system, the spectrum of communication device 1 after passing through the communication optical fiber is as follows: Figure 2 As shown, the spectrum of communication device 2 after passing through the communication optical fiber is as follows: Figure 3 As shown, the distributed fiber optic vibration sensing system detects signals as follows: Figure 4 As shown; after accessing the converged system, the spectra of communication device 1 and communication device 2 are respectively as follows: Figure 5 , Figure 6 As shown, the distributed fiber optic vibration sensing system detects signals as follows: Figure 7 As shown.

[0041] Testing revealed that when communication device 1 transmits data via the link to communication device 2, the additional insertion loss (excluding fiber loss) introduced by the fusion system is approximately 3.2 dB; when communication device 2 transmits data to communication device 1, the additional insertion loss is approximately 2.4 dB; and the additional insertion loss of the distributed fiber vibration system is approximately 0.8 dB. After introducing a Raman amplifier, the signal amplification of communication device 1 is approximately 9 dB, and that of communication device 2 is approximately 6.6 dB. The signal-to-noise ratio (SNR) of communication device 1 before connection is approximately 66.7 dB, and after connection is approximately 56.8 dB, a degradation of 9.9 dB; the SNR of communication device 2 before connection is approximately 52.9 dB, and after connection is approximately 47.3 dB, a degradation of 5.6 dB. The fusion system exhibits good isolation, preventing sensor light from entering the communication devices. Although the sensor signal strength decreases due to insertion loss, it remains relatively strong compared to the noise signal, not affecting the detection effect, thus achieving co-fiber transmission between the single-sensor unidirectional system and the communication devices.

[0042] according to Figure 1 The schematic diagram shows the connection system, where filter 1 has a center wavelength of C36 (ITU wavelength table, 1548.51nm) and a filtering bandwidth of 100GHz; filter 2 has a center wavelength of C35 (ITU wavelength table, 1549.32nm) and a filtering bandwidth of 100GHz. The fiber optic sensing device uses a distributed vibration sensing system, with an output light wavelength λ3 of C18 (ITU wavelength table, 1563.05nm). Communication device 1 outputs a wavelength of C36 with an output light intensity of 13.1dBm; communication device 2 outputs a wavelength of C35 with an output light intensity of 12.05dBm. The length of the communication fiber is approximately 70km.

[0043] Before connecting to the system, communication devices 1 and 2 were connected to the spectrometer via optical fibers, and the results were as follows: Figure 2 , 3 As shown. The coherent signal collected by the distributed vibration sensing system before connection to the system is as follows. Figure 4 As shown in the figure. After connecting to the system, the optical fibers at both ends of communication 1 and communication 2 are respectively connected to the spectrometer, and the results are as follows. Figure 5 , 6 As shown in Figure 7. According to the filter datasheet, the insertion loss at the transmission end is approximately 0.8 dB, and the insertion loss at the reflection end is approximately 0.4 dB. Therefore, for communication device 1, the additional insertion loss due to the fusion system (excluding the loss from the communication fiber) when reaching communication device 2 after passing through the link is approximately 3.2 dB. For communication device 2, the additional insertion loss when reaching communication device 1 after passing through the link is approximately 2.4 dB. For the distributed fiber optic vibration system, the additional insertion loss is approximately 0.8 dB.

[0044] Because the distributed fiber optic vibration sensing system incorporates Raman amplifiers for long-distance detection, and as broadband optical signal amplification devices, Raman amplifiers amplify C-band light. Therefore, in actual commissioning, the optical signals from Communication 1 and Communication 2 did not incur additional insertion loss after passing through the fusion system. After amplification by the Raman amplifier, the signals from both Communication 1 and Communication 2 were amplified. The signal from Communication 1 was amplified by approximately 9 dB, and the signal from Communication 2 by approximately 6.6 dB. Due to the inherent noise floor of the amplifiers in the distributed fiber optic vibration sensing system, the signal-to-noise ratio (SNR) of the communication devices was degraded to some extent. For Communication 1, before accessing the fusion system, its SNR was approximately 66.7 dB. After accessing the fusion system, its SNR was approximately 56.8 dB, a degradation of 9.9 dB. For Communication 2, before accessing the fusion system, its SNR was approximately 52.9 dB. After accessing the fusion system, its SNR was approximately 47.3 dB, a degradation of 5.6 dB. Meanwhile, due to the isolation effect of the fusion system, the sensing light from the fiber optic sensing device does not enter the communication device.

[0045] Since distributed vibration sensing does not provide additional amplification, and the system introduces approximately 0.8 dB of insertion loss and a reduction in Raman amplification, the detected coherent vibration signal will decrease. However, even with the decrease in optical signal intensity, the detected vibration signal remains relatively strong compared to the noise signal, thus having a minimal impact on the detection performance. Figure 1 The fusion method shown can effectively integrate single-sensor unidirectional systems with communication equipment to achieve co-fiber transmission in communication optical fibers.

[0046] Example 2

[0047] according to Figure 1-8 As shown, this embodiment proposes a multi-system sensing fusion method based on communication lines, adapting to sensing fusion scenarios between single-sensor round-trip systems and communication devices:

[0048] System parameters are determined: Communication fiber line station 1 and station 2 are equipped with communication equipment 1 and communication equipment 2 respectively, with signal light wavelengths of λ1 and λ2 respectively; the single-sensor round-trip system to be merged has a distributed fiber vibration sensing system (or a distributed fiber Brillouin optical time domain reflectometer) at the front end and a fiber amplifier (or a distributed fiber sensing system) at the back end, with sensing light wavelength of λ3 for both.

[0049] Filter selection: Two sets of three-port fiber optic filters were selected. The center wavelength of filter 1 is λ1 and the center wavelength of filter 2 is λ2. The filtering bandwidth of both is 100GHz. The insertion loss at the transmission end is about 0.8dB and the insertion loss at the reflection end is about 0.4dB.

[0050] Topology connection: The output light of communication device 1 (site 1) enters the Com input terminal of filter 2. The signal light with wavelength λ1 is output from the Ref port and enters the filter port of filter 1, and is output from the Com port and enters the communication optical fiber. After the signal light λ1 is transmitted through the communication optical fiber, it enters from the Com port of filter 2 of site 2, is output from the Ref port and enters the Com port of filter 1 of site 2, is then output from the filter port and enters the filter port of filter 1 of site 2, and is output from the Com port and enters communication device 2.

[0051] The output light λ2 of communication device 2 enters the Com port of filter 1 of station 2, exits from the Ref port and enters the filter port of filter 2 of station 2, and exits from the Com port and enters the communication optical fiber; after the signal light λ2 is transmitted through the communication optical fiber, it enters the Com port of filter 1 of station 1, exits from the Ref port and enters the Com port of filter 2 of station 1, exits from the filter port and enters the filter port of filter 2 of station 1, and exits from the Com port and enters communication device 1, realizing bidirectional transmission of communication signals.

[0052] The signal light λ3 output from the front end of the fiber optic sensing device enters the Ref port of filter 1 at station 2, exits from the Com port and enters the Ref port of filter 2 at station 2, and then exits from the Com port into the communication fiber optic cable; the backscattered signal returns along the original path to the front end of the fiber optic sensing device. The output light λ3 from the back end of the fiber optic sensing device passes through the Ref port of filter 2 at station 1, exits from the Com port and enters the Ref port of filter 1 at station 1, and then exits from the Com port into the communication fiber optic cable; after being transmitted through the communication fiber optic cable, the signal light λ3 passes through the Com port-Ref port of filter 2 at station 2, the Com port-Ref port of filter 1 at station 2, and enters the Com port of filter 1 at station 2. The filtering port enables the detection of the communication fiber optic cable or the amplification of the front end signal light.

[0053] Verification Results: This embodiment uses the same filter parameters and insertion loss standard as Embodiment 1, enabling crosstalk-free co-fiber transmission of communication and sensing signals. The back end of the fiber optic sensing device can effectively perform comprehensive testing of the communication fiber or amplify the front-end sensing signal light, solving the problem that existing technologies cannot achieve round-trip signal transmission and adapting to application scenarios requiring bidirectional sensing detection.

[0054] Example 3

[0055] according to Figure 1-9 As shown, this embodiment proposes a multi-system sensing fusion method based on communication lines, which is suitable for sensing fusion scenarios between multi-sensor unidirectional systems and communication devices:

[0056] System parameters are determined: Communication fiber line site 1 and site 2 are equipped with communication equipment 1 and communication equipment 2, respectively, with signal light wavelengths of λ1 and λ2, respectively; the multi-sensor unidirectional system to be integrated includes a distributed fiber vibration sensing system, a distributed fiber Brillouin optical time domain reflectometer, and a distributed fiber Raman sensing system (DTS), with sensing light wavelengths of λ3, λ4, and λ5, respectively, and each wavelength does not overlap and does not conflict with the communication signal wavelength.

[0057] Filter selection: Four sets of three-port fiber optic filters were selected. The center wavelength of filter 1 is λ1, the center wavelength of filter 2 is λ2, the center wavelength of filter 3 is λ3, and the center wavelength of filter 4 is λ4. The filtering bandwidth of each filter is 100GHz. The insertion loss at the transmission end is about 0.8dB, and the insertion loss at the reflection end is about 0.4dB.

[0058] Topology connection: The output light of communication device 1 (site 1) enters the Com input terminal of filter 2. The signal light with wavelength λ1 is output from the Ref port and enters the filter port of filter 1, and is output from the Com port and enters the communication optical fiber. After the signal light λ1 is transmitted through the communication optical fiber, it enters from the Com port of filter 2 of site 2, is output from the Ref port and enters the Com port of filter 1 of site 2, is then output from the filter port and enters the filter port of filter 1 of site 2, and is output from the Com port and enters communication device 2.

[0059] The output light λ2 of communication device 2 enters the Com port of filter 1 of station 2, exits from the Ref port and enters the filter port of filter 2 of station 2, and exits from the Com port and enters the communication optical fiber; after the signal light λ2 is transmitted through the communication optical fiber, it enters the Com port of filter 1 of station 1, exits from the Ref port and enters the filter port of filter 2 of station 1, and exits from the Com port and enters communication device 1, realizing bidirectional transmission of communication signals.

[0060] The output light of the fiber optic sensing device 1 (λ3) enters the filter port of filter 3, is output from the Com port to the Ref port of filter 1 of station 2, is output from the Com port to the Ref port of filter 2 of station 2, and is then output from the Com port to the communication fiber. The backscattered signal returns to the fiber optic sensing device 1 along the original path.

[0061] The output light of the fiber optic sensing device 2 (λ4) enters the filter port of filter 4, is output from the Com port to the Ref port of filter 3, is output from the Com port to the Ref port of filter 1 of station 2, is output from the Com port to the Ref port of filter 2 of station 2, and is then output from the Com port to the communication optical fiber. The backscattered signal returns to the fiber optic sensing device 2 along the original path.

[0062] The output light of the DTS system (λ5) enters the Ref port of filter 4, exits from the Com port and enters the Ref port of filter 3, exits from the Com port and enters the Ref port of filter 1 of station 2, exits from the Com port and enters the Ref port of filter 2 of station 2, and then exits from the Com port and enters the communication optical fiber; the backscattered signal wavelength does not pass through λ1, λ2, λ3, λ4, and returns to the DTS system along the original path.

[0063] Verification Results: In this embodiment, multiple sensing systems and communication devices achieve co-fiber transmission, with no interference between signal wavelengths and good isolation; the backscattered signals of each sensing system can be accurately returned, and the detection effect is stable. This solves the problem that existing technologies cannot achieve co-fiber fusion of multiple sensing systems, greatly improves the utilization rate of optical fiber resources, and is suitable for multi-parameter, large-scale sensing scenarios.

[0064] Example 4

[0065] according to Figure 1-10 As shown, this embodiment proposes a multi-system sensing fusion method based on communication lines, adapting to sensing fusion scenarios involving multi-sensor round-trip systems and communication devices:

[0066] System parameters are determined as follows: Communication fiber optic line site 1 and site 2 are equipped with communication equipment 1 and communication equipment 2, respectively, with signal light wavelengths of λ1 and λ2, respectively; the multi-sensor round-trip system to be integrated includes two sets of distributed fiber optic vibration sensing systems (or distributed fiber optic Brillouin optical time domain reflectometers) and one DTS system. Each sensing system is equipped with a front end and a back end (fiber optic amplifier or sensing system), with sensing light wavelengths of λ3, λ4, and λ5, respectively. The wavelengths do not overlap and do not conflict with the communication signal wavelengths.

[0067] Filter selection: Four sets of three-port fiber optic filters were selected. The center wavelength of filter 1 is λ1, the center wavelength of filter 2 is λ2, the center wavelength of filter 3 is λ3, and the center wavelength of filter 4 is λ4. The filtering bandwidth of each filter is 100GHz. The insertion loss at the transmission end is about 0.8dB, and the insertion loss at the reflection end is about 0.4dB.

[0068] Topology connection: The output light of communication device 1 (site 1) enters the Com input terminal of filter 2. The signal light with wavelength λ1 is output from the Ref port and enters the filter port of filter 1, and is output from the Com port and enters the communication optical fiber. After the signal light λ1 is transmitted through the communication optical fiber, it enters from the Com port of filter 2 of site 2, is output from the Ref port and enters the Com port of filter 1 of site 2, is then output from the filter port and enters the filter port of filter 1 of site 2, and is output from the Com port and enters communication device 2.

[0069] The output light λ2 of communication device 2 enters the Com port of filter 1 of station 2, exits from the Ref port and enters the filter port of filter 2 of station 2, and exits from the Com port and enters the communication optical fiber; after the signal light λ2 is transmitted through the communication optical fiber, it enters the Com port of filter 1 of station 1, exits from the Ref port and enters the Com port of filter 2 of station 1, exits from the filter port and enters the filter port of filter 2 of station 1, and exits from the Com port and enters communication device 1, realizing bidirectional transmission of communication signals.

[0070] The output light from the front end (λ3) of the fiber optic sensing device 1 enters the filtering port of filter 3, exits from the Com port and enters the Ref port of filter 1 of station 2, exits from the Com port and enters the Ref port of filter 2 of station 2, and then exits from the Com port into the communication fiber. The backscattered signal returns to the front end along the original path. The output light from the back end (λ3) of the fiber optic sensing device 1 enters the filtering port of filter 3, exits from the Com port and enters the Ref port of filter 2 of station 1, exits from the Com port and enters the Ref port of filter 1 of station 1, and then exits from the Com port into the communication fiber. After being coupled by filter 2 and filter 1 of station 2, it enters the Com port of filter 3, and detection or signal amplification is achieved through the filtering port.

[0071] The output light from the front end (λ4) of the fiber optic sensing device 2 enters the filtering port of filter 4, is output from the Com port to the Ref port of filter 3, is output from the Com port to the Ref port of filter 1 of station 2, is output from the Com port to the Ref port of filter 2 of station 2, and is then output from the Com port into the communication fiber optic cable. The backscattered signal returns to the front end along the original path. The output light from the rear end (λ4) of the fiber optic sensing device 2 enters the filtering port of filter 4, is output from the Com port to the Ref port of filter 3, is output from the Com port to the Ref port of filter 2 of station 1, is output from the Com port to the Ref port of filter 1 of station 1, and is then output from the Com port into the communication fiber optic cable. After coupling through filters 2, 1, and 3 of station 2, it enters the Com port of filter 4, where detection or signal amplification is achieved.

[0072] The output light of the DTS system (λ5) enters the Ref port of filter 4, exits from the Com port and enters the Ref port of filter 3, exits from the Com port and enters the Ref port of filter 1 of station 2, exits from the Com port and enters the Ref port of filter 2 of station 2, and then exits from the Com port and enters the communication optical fiber; the backscattered signal wavelength does not pass through λ1, λ2, λ3, λ4, and returns to the DTS system along the original path.

[0073] Verification Results: This embodiment achieves the co-fiber integration of multiple reciprocating sensing systems and communication equipment. The signal transmission at the front and back ends of each sensing system is stable, enabling comprehensive detection and signal amplification of the communication optical fiber. The signal isolation is good, with no crosstalk, making it suitable for complex application scenarios involving multiple sensors and bidirectional detection, and further improving the utilization efficiency of optical fiber resources.

[0074] Example 5

[0075] according to Figure 1-11 As shown, this embodiment proposes a multi-system sensing fusion method based on communication lines, which is suitable for sensing fusion scenarios of multi-sensor round-trip systems and communication devices with arbitrary wavelengths, without requiring specific wavelengths of the communication devices:

[0076] System parameters are determined as follows: Communication fiber optic line site 1 and site 2 are equipped with communication equipment 1 and communication equipment 2, respectively, with signal light wavelengths of λ1 and λ2, respectively. λ1 and λ2 are not limited to a single wavelength and can be any wavelength. The multi-sensor round-trip system to be integrated includes two sets of distributed fiber optic vibration sensing systems (or distributed fiber optic Brillouin optical time domain reflectometers) and one DTS system. Each sensing system has a front end and a back end, with sensing light wavelengths of λ3, λ4 and λ5, respectively, and the wavelengths do not overlap.

[0077] Filter selection: Five sets of three-port fiber optic filters were selected. The center wavelength of filter 7 is 1450nm, the center wavelength of filter 6 is 1660nm, the center wavelength of filter 5 is λ5, the center wavelength of filter 4 is λ4, and the center wavelength of filter 3 is λ3. The filtering bandwidth of each filter is 100GHz. The insertion loss at the transmission end is about 0.8dB, and the insertion loss at the reflection end is about 0.4dB.

[0078] Topology: The output light of communication device 1 (site 1) enters the Ref port of filter 3, exits from the Com port into the Ref port of filter 4, exits from the Com port into the Ref port of filter 5, and exits from the Com port into the communication optical fiber; the signal light λ1, after being transmitted through the communication optical fiber, enters from the Com port of filter 7 of site 2, exits from the Ref port into the Com port of filter 6 of site 2, exits from the Ref port into the Com port of filter 5 of site 2, exits through the Ref port into the Com port of filter 4 of site 2, exits through the Ref port into the Com port of filter 3 of site 2, and exits through the Ref port into communication device 2.

[0079] The output light λ2 from communication device 2 enters the Ref port of filter 3 at station 2, exits from the Com port to the Ref port of filter 4 at station 2, exits from the Com port to the Ref port of filter 5 at station 2, exits from the Com port to the Ref port of filter 6 at station 2, exits from the Com port to the Ref port of filter 7 at station 2, and exits from the Com port into the communication optical fiber; after the signal light λ2 is transmitted through the communication optical fiber, it enters the Com port of filter 5 at station 1, exits through the Ref port to the Com port of filter 4 at station 1, exits through the Ref port to the Com port of filter 3 at station 1, and exits through the Ref port into communication device 1, realizing bidirectional transmission of communication signals of arbitrary wavelength.

[0080] The output light from the front end (λ3) of the fiber optic sensing device 1 enters the filter port of filter 3 at station 2, and from the Com port it enters the Ref port of filter 4 at station 2, from the Com port it enters the Ref port of filter 5 at station 2, from the Com port it enters the Ref port of filter 6 at station 2, from the Com port it enters the Ref port of filter 7 at station 2, and from the Com port it enters the communication fiber. The backscattered signal returns to the front end along the original path. The output light from the back end (λ3) of the fiber optic sensing device 1 enters the filter port of filter 3 at station 1, and from the Com port it enters the Ref port of filter 4 at station 1, from the Com port it enters the Ref port of filter 5 at station 1, and from the Com port it enters the communication fiber. After being coupled by filters 7, 6, 5, 4, and 3 at station 2, detection or signal amplification is achieved.

[0081] The output light from the front end (λ4) of the fiber optic sensing device 2 enters the filter port of filter 4 of station 2, and from the Com port it enters the Ref port of filter 5 of station 2, from the Com port it enters the Ref port of filter 6 of station 2, from the Com port it enters the Ref port of filter 7 of station 2, and from the Com port it enters the communication fiber. The backscattered signal returns to the front end along the original path. The output light from the back end (λ4) of the fiber optic sensing device 2 enters the filter port of filter 4 of station 1, and from the Com port it enters the Ref port of filter 5 of station 1. From the Com port it enters the communication fiber. After being coupled by filters 7, 6, 5 and 4 of station 2, detection or signal amplification is achieved.

[0082] The output light of the DTS system (λ5) enters the Com port of filter 7 at station 2, exits from the Ref port to the Com port of filter 6 at station 2, exits from the Ref port to the filter port of filter 5 at station 2, exits from the Com port to the Ref port of filter 6 at station 2, exits from the Com port to the Ref port of filter 7 at station 2, and exits from the Com port into the communication optical fiber; the back-Stokes light (around 1450nm) returns to the DTS along the Com port-filter port-filter port-Com port of filter 7 at station 2; the back-Stokes light (around 1660nm) returns to the DTS along the Com port-Ref port-Com port-filter port-filter port-filter port-Ref port-Com port of filter 7 at station 2.

[0083] Verification Results: This embodiment does not require specifying the specific wavelength of the communication equipment and can be adapted to the sensing fusion of communication equipment with any wavelength. Multiple sets of reciprocating sensing systems and communication equipment achieve crosstalk-free co-fiber transmission. The DTS system can accurately receive back-facing anti-Stokes light and back-facing Stokes light, and the detection effect is stable. It solves the limitation of existing technologies that cannot be adapted to communication equipment with any wavelength and further expands the application scope of the technology.

[0084] This multi-system sensing fusion method based on communication lines employs a cascaded coupling approach using three-port filters. It eliminates the need for co-modulation modifications at the equipment level and requires no customized adjustments to existing communication equipment and distributed fiber optic sensing systems, achieving plug-and-play compatibility with existing distributed independent systems. This significantly reduces the modification costs and implementation difficulty of sensing fusion, expanding the application scope of the technology. This invention abandons the traditional active amplification approach, achieving signal coupling solely through the port characteristics of the three-port filter. It eliminates the need for additional power supply equipment such as optical amplifiers, reducing equipment investment and operating costs while avoiding the inconvenience caused by additional power supplies. Furthermore, it eliminates the need for customized light sources for the sensing system, making it compatible with conventional distributed fiber optic sensing systems, further enhancing the practicality and versatility of the technology. This invention enables flexible adaptation between single and multiple sensors, and between one-way and round-trip transmission. It is also compatible with communication devices of any wavelength. Through topology matching of filters, it ensures that signals do not interfere with each other when multiple wavelengths and multiple systems coexist. Even when Raman amplifiers are introduced for long-distance transmission, the signal-to-noise ratio of each system remains controllable, and the detection effect of the sensing signal is not substantially affected. This effectively improves the utilization rate of optical fiber resources and provides reliable technical support for large-scale sensing in fields such as communication networks, smart cities, and energy security.

[0085] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-system sensing fusion method based on communication lines, characterized in that: Includes the following steps: S1: Determine the communication equipment and its signal wavelength at both ends of the communication fiber optic line site, and determine at least one distributed fiber optic sensing system to be integrated and its sensing wavelength. S2: Select at least one set of three-port fiber optic filters, and set the center wavelength of each three-port fiber optic filter according to the wavelength of the communication equipment signal light and the wavelength of the sensing light, so that the wavelengths of the communication signal light and the sensing signal light do not overlap, thus ensuring signal isolation. S3: Connect the communication equipment, distributed optical fiber sensing system and three-port optical fiber filter in a topology. Utilize the characteristics of the Com port, Ref port and filter port of the three-port filter to achieve passive coupling between the communication signal light and the sensing signal light. S4: Connect the coupled signal light to the communication optical fiber to realize the co-fiber transmission between the communication equipment and the distributed optical fiber sensing system. The backscattered signal generated by the sensing signal light in the communication optical fiber returns to the corresponding distributed optical fiber sensing system along the original path. The distributed optical fiber sensing system is a multi-sensor round-trip system. In step S2, two sets of three-port optical fiber filters matching the wavelength of the communication equipment are selected, along with at least two sets of three-port optical fiber filters matching the wavelength of each sensing system. In step S3, the topology connection is as follows: the output light from the communication equipment of station 1 is connected to the Com port of the corresponding filter; the wavelength-matched communication signal light is output from the Ref port of that filter, connected to the filter port of another set of corresponding filters, and then output from the Com port of that filter to the communication optical fiber; the communication signal light transmitted through the communication optical fiber is connected to the Com port of the corresponding filter of station 2, output from its Ref port to the Com port of another set of corresponding filters, and then output from the filter port of that filter to the communication equipment of station 2; the communication equipment of station 2 outputs… The optical signal is connected to the Com port of the corresponding filter, and the wavelength-matched communication signal light is output from the Ref port of the filter, connected to the filter port of another set of corresponding filters, and then output from the Com port of the filter to the communication optical fiber; the communication signal light transmitted in the communication optical fiber is connected to the Com port of the corresponding filter of station 1, output from its Ref port to the Com port of another set of corresponding filters, and then output from the filter port of the filter to the communication equipment of station 1; the output light from the front end of each optical fiber sensing device is coupled to the communication optical fiber after being coupled by the corresponding filter, and the backscattered signal returns along the original path; the output light from the back end of each optical fiber sensing device is coupled to the communication optical fiber after being coupled by the corresponding filter in multiple stages, and then coupled by the far-end filter to realize the detection of the communication optical fiber or the amplification of the signal light from the front end of the corresponding sensing device.

2. The multi-system sensing fusion method based on communication lines according to claim 1, characterized in that: The communication equipment is an arbitrary wavelength communication equipment. In step S2, two sets of three-port fiber filters with center wavelengths of 1450nm and 1660nm are selected, as well as at least three sets of three-port fiber filters that match the wavelengths of each sensing system. In step S3, the topology connection is as follows: the output light of the two-site communication equipment is coupled through multi-stage filters and then connected to the communication fiber to realize the transmission of arbitrary wavelength communication signals; the output light of the front end and back end of each fiber sensing device is coupled through corresponding filters through multi-stage coupling and then connected to the communication fiber; the backscattered signal of the sensing signal returns along its respective path, wherein the backscattered anti-Stokes light and backscattered Stokes light of the distributed fiber Raman sensing system (DTS) are coupled through corresponding filters and then returned to the DTS device.

3. The multi-system sensing fusion method based on communication lines according to claim 2, characterized in that: The three-port fiber optic filter has a filtering bandwidth of 100 GHz, an insertion loss of 0.8 dB at the transmission end, and an insertion loss of 0.4 dB at the reflection end.

4. The multi-system sensing fusion method based on communication lines according to claim 3, characterized in that: The distributed optical fiber sensing system includes one or more of the following: a distributed optical fiber vibration sensing system, a distributed optical fiber Brillouin optical time domain reflectometer, and a distributed optical fiber Raman sensing system (DTS); the back end of the optical fiber sensing device is an optical fiber amplifier or a distributed optical fiber sensing system.

5. The multi-system sensing fusion method based on communication lines according to claim 4, characterized in that: When communication optical fibers are used for long-distance transmission, Raman amplifiers are introduced. Raman amplifiers have a broadband gain effect on C-band light, which compensates for the insertion loss caused by fusion and amplifies the communication signal light.

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