A fiber optic sensing method based on dual-wavelength light source

Abstract

The present invention discloses a fiber optic sensing method based on a dual-wavelength light source. The method comprises: obtaining a forward sensing light signal and a set of local oscillator light signals; inputting the forward sensing light signal into the fiber optic sensor to be tested to obtain a feedback light signal; determining a sensing data set according to the feedback light signal and the set of local oscillator light signals; evaluating at least one parameter corresponding to the fiber optic sensor to be tested according to the sensing data set to obtain an evaluation result of each parameter corresponding to the fiber optic sensor to be tested. Through the technical solution of the present invention, the amount of optical fiber used in sensing applications in power optical cables can be reduced, the additional circuit or optical path connection required for synchronization between different sensing systems can be avoided, the reduction in signal-to-noise ratio caused by power attenuation in Brillouin scattering can be reduced, and the frequency shift extraction accuracy of BOTDR can be improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of optical fiber sensing technology, and in particular to an optical fiber sensing method based on a dual-wavelength light source. Background Art

[0002] With the rapid development of optical fiber communication, the research and development of optical fiber sensors has attracted great attention worldwide, and optical fiber sensing technology has also been widely used. In the power system, the continuous construction and popularization of power communication networks, the safety and health monitoring of power optical cables, and the timely detection or prediction of faults are becoming more and more important to reduce losses.

[0003] On power optical cables, it is often necessary to synchronously detect changes in physical quantities such as temperature, strain and vibration, and to replay the impact of the external environment on the power optical cables in multiple dimensions. In this way, while determining the location and time of abnormal events in communication optical cables, the nature of abnormal events in communication optical cables and the causes of abnormal events can be determined to eliminate the factors causing power optical cable failures from the source or predict the occurrence of power optical cable failures. However, the application of different types of optical fiber sensing systems on the same optical fiber sensing link will not only increase the overall cost, but also occupy too many idle fiber cores of power optical cables. On the other hand, in distributed optical fiber sensing systems, the detection of changes in physical quantities such as temperature, strain and vibration all rely on low-loss sensing optical fiber links. The loss on the sensing optical fiber link often interferes with the monitoring of the above-mentioned physical quantity changes, especially the Brillouin Optical Time Domain Reflectometry (BOTDR) technology uses the weaker Brillouin scattered light signal as the detection object, and the loss on the optical fiber link will have a greater negative impact on the sensing sensitivity of BOTDR. The sensing optical signal has a lot of loss attenuation in the sensing optical fiber link. In addition to the unavoidable loss attenuation such as intrinsic loss, the loss that has a great impact on the sensing optical signal mainly comes from the loss related to the attenuation coefficient caused by factors such as bending and the insertion loss of the connection part. There are also some manufacturing losses introduced in the optical fiber manufacturing process. Once these losses occur, it is difficult to avoid or eliminate them after the optical cable is deployed, which will make it difficult to obtain accurate quantitative detection of changes in physical quantities such as temperature, strain and vibration at some sensing points or sensing segments on the sensing optical fiber link.

[0004] In view of this, how to overcome the defects of the existing technology and solve the problem of insufficient effectiveness of the current operation and maintenance personnel tracking system is a problem to be solved in this technical field. Summary of the invention

[0005] The embodiment of the present invention provides a fiber optic sensing method based on a dual-wavelength light source, so as to reduce the amount of optical fiber used in sensing applications in power optical cables, avoid additional circuit or optical path connections required for synchronization between different sensing systems, reduce the reduction in signal-to-noise ratio caused by power attenuation in Brillouin scattering, and improve the frequency shift extraction accuracy of BOTDR.

[0006] According to one aspect of the present invention, there is provided a fiber optic sensing method based on a dual-wavelength light source, comprising:

[0007] Acquire a forward sensing light signal and a local oscillator light signal set;

[0008] Inputting the forward sensing light signal into the optical fiber sensor to be tested to obtain a feedback light signal;

[0009] Determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set;

[0010] At least one parameter corresponding to the optical fiber sensor to be tested is evaluated according to the sensing data set to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0011] According to another aspect of the present invention, there is provided an optical fiber sensing device based on a dual-wavelength light source, the device comprising:

[0012] An acquisition module, used for acquiring a forward sensing light signal and a local oscillator light signal set;

[0013] An input module, used for inputting the forward sensing optical signal into the optical fiber sensor to be tested to obtain a feedback optical signal;

[0014] A determination module, configured to determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set;

[0015] The evaluation module is used to evaluate at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set, and obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0016] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0017] at least one processor; and

[0018] a memory communicatively connected to the at least one processor; wherein,

[0019] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the optical fiber sensing method based on a dual-wavelength light source described in any embodiment of the present invention.

[0020] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the optical fiber sensing method based on a dual-wavelength light source described in any embodiment of the present invention when executed.

[0021] The embodiment of the present invention obtains a forward sensing light signal and a set of local oscillator light signals, inputs the forward sensing light signal into the optical fiber sensor to be tested, obtains a feedback light signal, determines a sensing data set according to the feedback light signal and the set of local oscillator light signals, evaluates at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set, and obtains an evaluation result of each parameter corresponding to the optical fiber sensor to be tested. Through the technical solution of the present invention, the amount of optical fiber used in sensing applications in power optical cables can be reduced, the additional circuit or optical path connection required for synchronization between different sensing systems can be avoided, the reduction in signal-to-noise ratio caused by power attenuation of Brillouin scattering can be reduced, and the frequency shift extraction accuracy of BOTDR can be improved.

[0022] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a flow chart of a fiber optic sensing method based on a dual-wavelength light source in an embodiment of the present invention;

[0025] Figure 2 is a structural diagram of an optical fiber sensing system based on a dual-wavelength light source in an embodiment of the present invention;

[0026] Figure 3 is a schematic structural diagram of an optical fiber sensing device based on a dual-wavelength light source in an embodiment of the present invention;

[0027] Figure 4 It is a schematic structural diagram of an electronic device for implementing the optical fiber sensing method based on a dual-wavelength light source according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] Embodiment 1

[0031] Figure 1 is a flow chart of a fiber optic sensing method based on a dual-wavelength light source in an embodiment of the present invention. This embodiment is applicable to the case of fiber optic sensing based on a dual-wavelength light source. The method can be executed by a fiber optic sensing device based on a dual-wavelength light source in an embodiment of the present invention. The device can be implemented in software and / or hardware, such as Figure 1 As shown, the method specifically comprises the following steps:

[0032] S101, obtaining a forward sensing light signal and a set of local oscillator light signals.

[0033] In this embodiment, the forward sensing light signal may be an optical signal input into the optical fiber sensor to be tested and used to detect the optical fiber sensor to be tested.

[0034] Optionally, the local oscillator optical signal set includes: a first local oscillator optical signal and a second local oscillator optical signal.

[0035] Obtain a forward sensing light signal and a local oscillator light signal set, including:

[0036] Obtain dual-wavelength optical signals.

[0037] In this embodiment, the dual-wavelength optical signal can be a laser signal emitted by a dual-wavelength laser. The first wavelength laser in the dual-wavelength laser is a narrow linewidth laser with a central wavelength of 1550.12nm and a linewidth of 100kHz, which is used as a BOTDR (Brillouin Optical Time Domain Reflectometry) and φ-OTDR (φ-Optical Time Domain Reflectometer) light source; the second wavelength laser in the dual-wavelength laser has a central wavelength of 1560nm and a linewidth greater than or equal to 1nm, which is used as an optical time domain reflectometer light source. The OTDR is used to obtain distributed loss data by distributed detection of scattering intensity changes.

[0038] The dual-wavelength optical signal is divided to obtain a forward sensing optical signal, a first local oscillation optical signal and a second local oscillation optical signal.

[0039] In a specific embodiment, a dual-wavelength laser emits a dual-wavelength optical signal, which passes through a first optical splitter, and the first optical splitter divides the dual-wavelength optical signal into three paths: the first path is used as a forward sensing optical signal and input into the optical fiber sensor to be tested; the second path optical signal is used as a first local oscillation optical signal to participate in the interference of BOTDR, and the third path optical signal is used as a second local oscillation optical signal to participate in the interference of φ-OTDR. BOTDR is used for distributed detection of changes in physical quantities of temperature and strain; φ-OTDR is used for distributed detection of changes in physical quantities of vibration.

[0040] S102, inputting the forward sensing light signal into the optical fiber sensor to be tested to obtain a feedback light signal.

[0041] The optical fiber sensor to be tested may be a light sensor for which parameter evaluation is to be performed.

[0042] It should be explained that the feedback optical signal may be a signal transmitted back by the optical fiber sensor to be tested after the forward sensing optical signal is input into the optical fiber sensor to be tested.

[0043] Specifically, the forward sensing light signal is input into the optical fiber sensor to be tested, and a signal transmitted back by the optical fiber sensor to be tested is obtained.

[0044] S103: Determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set.

[0045] It should be noted that the sensing data set may be a set of sensing data used to evaluate each parameter of the optical fiber sensor to be tested.

[0046] Specifically, the sensing data set is determined according to the feedback optical signal and the local oscillator optical signal set.

[0047] S104. Evaluate at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0048] The parameters may be parameters corresponding to the optical fiber sensor to be tested and used to characterize certain properties of the optical fiber sensor to be tested. For example, the parameters corresponding to the optical fiber sensor to be tested may include temperature, strain, vibration, loss and other parameters.

[0049] The evaluation result may be a result obtained after evaluating each parameter corresponding to the optical fiber sensor to be tested.

[0050] Specifically, at least one parameter corresponding to the optical fiber sensor to be tested is evaluated according to the sensing data set to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, so that the staff can quickly determine the environmental conditions and damage conditions of the optical cable line.

[0051] The embodiment of the present invention obtains a forward sensing light signal and a set of local oscillator light signals, inputs the forward sensing light signal into the optical fiber sensor to be tested, obtains a feedback light signal, determines a sensing data set according to the feedback light signal and the set of local oscillator light signals, evaluates at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set, and obtains an evaluation result of each parameter corresponding to the optical fiber sensor to be tested. Through the technical solution of the present invention, the amount of optical fiber used in sensing applications in power optical cables can be reduced, the additional circuit or optical path connection required for synchronization between different sensing systems can be avoided, the reduction in signal-to-noise ratio caused by power attenuation of Brillouin scattering can be reduced, and the frequency shift extraction accuracy of BOTDR can be improved.

[0052] Optionally, the feedback optical signal includes: a first optical signal and a second optical signal; the first optical signal includes: a Brillouin scattered optical signal and a phase-sensitive reflected optical signal.

[0053] In a specific embodiment, the feedback optical signal transmitted from the optical fiber sensor to be tested is divided into two parts after passing through an optical wavelength division multiplexer: a first optical signal and a second optical signal. Specifically, the first optical signal is further divided into two parts after passing through an optical splitter: a Brillouin scattered optical signal and a phase-sensitive reflected optical signal.

[0054] The sensing data set is determined according to the feedback optical signal and the local oscillator optical signal set, including:

[0055] An envelope signal is determined according to the first local oscillation light signal and the Brillouin scattered light signal.

[0056] The envelope signal may be a signal obtained by coupling the first local oscillation light signal and the Brillouin scattered light signal.

[0057] Specifically, the first local oscillation light signal and the Brillouin scattered light signal are coupled to obtain a beat signal between the first local oscillation light signal and the Brillouin scattered light signal, the beat signal is filtered through a balanced detector and an electrical bandpass filter, and then detected by a detector to finally obtain an envelope signal.

[0058] A disturbance signal is determined according to the second local oscillation light signal and the phase-sensitive reflected light signal.

[0059] The disturbance signal may be a signal obtained by coupling the second local oscillation light signal and the phase-sensitive reflected light signal.

[0060] Specifically, the second local oscillation light signal and the phase-sensitive reflected light signal are coupled to obtain a beat signal between the second local oscillation light signal and the phase-sensitive reflected light signal, and the beat signal is passed through a balanced detector to finally obtain a disturbance signal.

[0061] A power signal is determined based on the second optical signal.

[0062] The power signal may be a signal used to evaluate the loss parameter of the optical fiber sensor to be tested.

[0063] Specifically, the second optical signal is input into the avalanche detector to obtain a power signal.

[0064] A sensing data set is determined based on the envelope signal, the disturbance signal, and the power signal.

[0065] Specifically, the data acquisition card collects three signals, namely, an envelope signal, a disturbance signal and a power signal, and sends the three signals to the processor, and the processor determines a sensor data set according to the three signals.

[0066] Optionally, the parameters corresponding to the optical fiber sensor to be tested include: at least one of: temperature parameters, strain parameters, vibration parameters and loss parameters.

[0067] Evaluating at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including:

[0068] At least one of the temperature parameter, strain parameter, vibration parameter and loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, envelope signal and power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0069] Specifically, the vibration parameters corresponding to the optical fiber sensor to be tested can be evaluated based on the disturbance signal to obtain the evaluation results of the vibration parameters corresponding to the optical fiber sensor to be tested; the temperature parameters or strain parameters corresponding to the optical fiber sensor to be tested can be evaluated based on the envelope signal to obtain the evaluation results of the temperature parameters or strain parameters corresponding to the optical fiber sensor to be tested; the loss parameters corresponding to the optical fiber sensor to be tested can be evaluated based on the power signal to obtain the evaluation results of the loss parameters corresponding to the optical fiber sensor to be tested.

[0070] Optionally, at least one of a temperature parameter, a strain parameter, a vibration parameter, and a loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, the envelope signal, and the power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including:

[0071] Get the current strength value of the disturbance signal.

[0072] The current intensity value may be an intensity value of the disturbance signal at the current moment.

[0073] In this embodiment, the intensity value of the disturbance signal is acquired in real time. According to the intensity value of the disturbance signal, it is judged that the intensity value of the disturbance signal will change after the optical fiber sensor to be tested is disturbed. The magnitude of the intensity value change is calculated, and according to the set threshold value, it is judged whether the optical fiber sensor to be tested vibrates.

[0074] If the current intensity value of the disturbance signal is different from the historical intensity value of the disturbance signal, the intensity change value of the disturbance signal is obtained.

[0075] It should be noted that the historical strength value may be the strength value of the disturbance signal obtained at a historical moment.

[0076] The intensity change value may be a change between a current intensity value of the disturbance signal and a historical intensity value of the disturbance signal.

[0077] Specifically, the current intensity value of the disturbance signal is obtained, the historical intensity value of the disturbance signal is obtained, and the two are compared. If the current intensity value of the disturbance signal is different from the historical intensity value of the disturbance signal, the intensity change value of the disturbance signal is calculated.

[0078] If the intensity change value of the disturbance signal is greater than or equal to the first preset threshold value, it is determined that the evaluation result of the vibration parameter is that the optical fiber sensor to be tested vibrates.

[0079] The first preset threshold may be a threshold pre-set by the user according to actual conditions, and this embodiment does not limit this.

[0080] Specifically, if the intensity change value of the disturbance signal is greater than or equal to the first preset threshold, the evaluation result of the vibration parameter is determined to be that the optical fiber sensor to be tested vibrates; if the intensity change value of the disturbance signal is less than the first preset threshold, the evaluation result of the vibration parameter is determined to be that the optical fiber sensor to be tested does not vibrate.

[0081] Optionally, at least one of a temperature parameter, a strain parameter, a vibration parameter, and a loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, the envelope signal, and the power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including:

[0082] The power variation of the envelope signal and the variation of the Brillouin frequency shift corresponding to the envelope signal are obtained.

[0083] The power variation may be the variation between the power of the envelope signal at the current moment and the power at the historical moment. The Brillouin frequency shift variation may be the variation between the Brillouin frequency shift corresponding to the envelope signal at the current moment and the historical moment.

[0084] Specifically, the power variation of the envelope signal and the Brillouin frequency shift variation corresponding to the envelope signal are obtained.

[0085] If the power variation of the envelope signal is greater than or equal to the second preset threshold, the temperature parameter corresponding to the optical fiber sensor to be tested is evaluated, and the evaluation result of the temperature parameter corresponding to the optical fiber sensor to be tested is determined according to the variation of the Brillouin frequency shift.

[0086] The second preset threshold may be a threshold pre-set by the user according to actual conditions, and this embodiment does not limit this.

[0087] In actual operation, the temperature parameter or strain parameter corresponding to the optical fiber sensor to be tested is evaluated according to the power change of the envelope signal and the second preset threshold. If the power changes, it belongs to temperature, and if there is no obvious change, it is strain.

[0088] Specifically, if the power change of the envelope signal is greater than or equal to the second preset threshold, the temperature parameter corresponding to the optical fiber sensor to be tested is evaluated, and the evaluation result of the temperature parameter corresponding to the disturbance position of the optical fiber sensor to be tested is determined according to the change of the Brillouin frequency shift.

[0089] If the power variation of the envelope signal is less than the second preset threshold, the strain parameter corresponding to the optical fiber sensor to be measured is evaluated, and the evaluation result of the strain parameter corresponding to the optical fiber sensor to be measured is determined according to the variation of the Brillouin frequency shift.

[0090] Specifically, if the power change of the envelope signal is less than the second preset threshold, the strain parameter corresponding to the optical fiber sensor to be tested is evaluated, and the evaluation result of the strain parameter corresponding to the disturbance position of the optical fiber sensor to be tested is determined according to the change of the Brillouin frequency shift.

[0091] Optionally, at least one of a temperature parameter, a strain parameter, a vibration parameter, and a loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, the envelope signal, and the power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including:

[0092] Get the current power value of the power signal.

[0093] The current power value may be the strength value of the power signal at the current moment.

[0094] In this embodiment, the power value of the power signal is acquired in real time, and the loss of the optical fiber sensor to be tested is measured based on the calculated power value variation.

[0095] If the current power value of the power signal is different from the historical power value of the power signal, the power change value of the power signal is acquired.

[0096] It should be noted that the historical power value may be a power value of a power signal acquired at a historical moment.

[0097] The power change value may be a change between a current power value of the power signal and a historical power value of the power signal.

[0098] Specifically, a current power value of the power signal is obtained, a historical power value of the power signal is obtained, and the two are compared. If the current power value of the power signal is different from the historical power value of the power signal, a power change value of the power signal is calculated.

[0099] The loss amount corresponding to the optical fiber sensor to be tested is determined according to the power change value of the power signal.

[0100] The loss amount may be the loss amount of the optical fiber sensor to be tested.

[0101] Specifically, the loss corresponding to the optical fiber sensor to be tested is measured according to the power change value of the power signal.

[0102] As an exemplary description of this embodiment, Figure 2 is a structural diagram of an optical fiber sensing system based on a dual-wavelength light source in an embodiment of the present invention. In a specific embodiment, the optical fiber sensing method based on a dual-wavelength light source in this embodiment can be implemented according to an optical fiber sensing system based on a dual-wavelength light source. Figure 2As shown, the optical fiber sensing system based on the dual-wavelength light source includes: a dual-wavelength laser, a first optical splitter, a SOA (Semiconductor Optical Amplifier), a pulse source, an EDFA (Erbium Doped Fiber Application Amplifier), a circulator, an optical fiber sensor to be tested, a WDM (Wavelength Division Multiplexer), a second optical splitter, an MZM (Mach-Zehnder Modulator), a microwave source, a polarization scrambler, a first coupler, a first detector (essentially a balanced detector), a bandpass filter, a detector, a radio frequency driver, an AOM (Acousto-optical Modulators), a second coupler, a balanced detector, an avalanche detector, a DAQ (Data Acquisition) and a processor.

[0103] Among them, the pulse source and the processor are connected through DAQ to synchronize the emission of pulses and the acquisition of signals. Data is transmitted between DAQ and the processor through PCIE (Peripheral Component Interconnect Express, a high-speed serial computer expansion bus standard). SOA is used to generate intensity-modulated optical pulses driven by the pulse source. The microwave source drives the MZM to modulate the intensity of the first local oscillator light to generate a double-sideband local oscillator light signal to achieve the frequency reduction of the beat frequency signal. The MZM is driven by a microwave source, and the output frequency of the microwave source is 10GHz to 12GHz to cover the Brillouin scattering frequency of the optical fiber. The point-by-point scanning step can be set to 2MHz.

[0104] The first optical splitter is connected to the AOM and the second coupler in sequence, and the RF driver is connected to the RF signal input terminal of the AOM. The AOM has a frequency shifting function, and the frequency of the second local oscillator optical signal is increased or decreased under the drive of the RF driver. Preferably, the acousto-optic modulator can increase the frequency of the second local oscillator optical signal by 80MHz. The purpose is to reduce the frequency of the beat signal after interference to facilitate the detection of the beat optical signal.

[0105] Among them, the WDM is connected in series between the circulator and the second optical splitter. Specifically, the multiplexing port of the WDM is connected to the third port of the circulator, the first frequency division port of the WDM is connected to the second optical splitter, and the second frequency division port of the WDM is connected to the avalanche detector. The feedback optical signal returned by the optical fiber sensor to be tested is divided into two parts after the WDM: the first optical signal and the second optical signal; specifically, the first optical signal is divided into two parts after passing through the second optical splitter: a Brillouin scattered optical signal and a phase-sensitive reflected optical signal; the Brillouin scattered optical signal is input into the first coupler to couple with the first local oscillator optical signal, and finally an envelope signal is obtained; the phase-sensitive reflected optical signal is input into the second coupler to couple with the second local oscillator optical signal, and finally a disturbance signal is obtained; the second optical signal is directly input into the avalanche detector, and finally a power signal is obtained.

[0106] A filter is connected in series between the first optical splitter and the MZM optical path to filter out the second wavelength optical signal contained in the first local oscillation light; a filter is connected in series between the first optical splitter and the AOM to filter out the first wavelength optical signal contained in the second local oscillation light.

[0107] Among them, the first coupler is used for BOTDR interference, and the second coupler is used for φ-OTDR (Phase-Sensitive Optical Time-Domain Reflectometer, phase-sensitive optical time domain reflectometer) interference. The dual-wavelength laser can be specifically an ultra-narrow linewidth (less than 1kHz) tunable laser operating at 1550.12nm. The pulse source specifically generates a rectangular pulse with a duration of about 100ns and a pulse period of 100us. The pulsed light signal passes through EDFA to increase the optical power of the optical signal. The amplified spontaneous emission of EDFA is filtered out by a filter (fiber Bragg grating) with a passband of about 0.8nm, and then the amplified pulsed light signal is injected into the optical fiber sensor to be tested through an optical circulator as a detection pulse.

[0108] The first optical splitter divides the dual-wavelength optical signal emitted by the dual-wavelength laser into three paths. The first path is used as a forward sensing optical signal to enter the optical fiber sensor to be tested through SOA, EFDA and circulator. The second path of optical signal is used as the first local oscillation optical signal to enter the first coupler through MZM and scrambler to participate in the interference of BOTDR. The third path of optical signal is used as the second local oscillation optical signal to enter the second coupler to participate in the interference of φ-OTDR. BOTDR is used for distributed detection of physical quantity changes of temperature and strain; φ-OTDR is used for distributed detection of physical quantity changes of vibration.

[0109] The splitting ratio of the first splitter is specifically 8:1:1, the second splitter may specifically be a common splitter with a splitting ratio of 50:50, the coupling ratio of the first coupler is 50:50, and the coupling ratio of the second coupler is 50:50.

[0110] The dual-wavelength laser is linearly polarized light, and the polarization direction is along the fast axis or slow axis (the optical axis of the polarization-maintaining fiber, the fiber output by the dual-wavelength laser is polarization-maintaining). Polarization-maintaining fiber is used to connect the dual-wavelength laser and the first beam splitter, the second coupler and the MZM, the MZM and the polarization scrambler, and the first beam splitter and the second coupler. The first beam splitter is specifically a polarization-maintaining beam splitter, and the second coupler is a polarization-maintaining coupler. The polarization-maintaining coupler and the polarization-maintaining fiber are used to maintain the original polarization state of the linearly polarized light, and prevent the local oscillator light signal from becoming an elliptically polarized light. The polarization state is affected by the temperature and stress changes on the local oscillator light path, and the local oscillator light polarization state is unstable, which affects the quality of the interference signal.

[0111] The first local oscillation light signal is coherent with the Brillouin scattered light signal through a 50:50 coupler and converted into an electrical signal by the first detector (essentially a balanced detector). The electrical signal then passes through a bandpass filter (center frequency 600MHz, bandwidth 30MHz) and a detector to obtain an envelope signal.

[0112] The polarization scrambler is connected in series on the optical path between the MZM and the first coupler. The polarization scrambler causes the polarization state of the laser to change rapidly and randomly to compensate for the polarization attenuation when the first local oscillator light signal interferes with the Brillouin scattered light signal.

[0113] The embodiment of the present invention adopts the BOTDR and φ-OTDR multiplexing technology of scattered signals, avoiding time-sharing switching on the optical path and reducing the amount of optical fiber used in sensing applications in power optical cables; in addition, due to the multiplexed scattered signals of sensing light, the detection of physical quantity changes of temperature, strain and vibration has good synchronization, avoiding the additional circuit or optical path connection required for synchronization between different sensing systems. On the other hand, the embodiment of the present invention uses another sensing light signal with a line width of 1nm generated by a dual-wavelength laser and BOTDR and φ-OTDR multiplexed sensing optical fiber to synchronously perform distributed loss quantitative detection on the sensing optical fiber, and uses the loss quantitative detection results to compensate for the power fluctuation caused by the loss of the Brillouin backscattering signal, reducing the reduction in signal-to-noise ratio caused by power attenuation of Brillouin scattering, and improving the frequency shift extraction accuracy of BOTDR.

[0114] Embodiment 2

[0115] Figure 3 is a schematic diagram of the structure of an optical fiber sensing device based on a dual-wavelength light source in an embodiment of the present invention. This embodiment is applicable to the case of optical fiber sensing based on a dual-wavelength light source. The device can be implemented in software and / or hardware. The device can be integrated in any device that provides the function of optical fiber sensing based on a dual-wavelength light source, such as Figure 3 As shown, the optical fiber sensing device based on a dual-wavelength light source specifically includes: an acquisition module 201 , an input module 202 , a determination module 203 and an evaluation module 204 .

[0116] Wherein, the acquisition module 201 is used to acquire a forward sensing light signal and a local oscillator light signal set;

[0117] An input module 202 is used to input the forward sensing optical signal into the optical fiber sensor to be tested to obtain a feedback optical signal;

[0118] A determination module 203, configured to determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set;

[0119] The evaluation module 204 is used to evaluate at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set, and obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0120] Optionally, the local oscillator optical signal set includes: a first local oscillator optical signal and a second local oscillator optical signal;

[0121] The acquisition module 201 includes:

[0122] An acquisition unit, used for acquiring a dual-wavelength optical signal;

[0123] The dividing unit is used to divide the dual-wavelength optical signal to obtain a forward sensing optical signal, a first local oscillation optical signal and a second local oscillation optical signal.

[0124] Optionally, the feedback optical signal includes: a first optical signal and a second optical signal; the first optical signal includes: a Brillouin scattered optical signal and a phase-sensitive reflected optical signal;

[0125] The determination module 203 includes:

[0126] A first determining unit, configured to determine an envelope signal according to the first local oscillator light signal and the Brillouin scattered light signal;

[0127] A second determining unit, configured to determine a disturbance signal according to the second local oscillator optical signal and the phase-sensitive reflected optical signal;

[0128] A third determining unit, configured to determine a power signal according to the second optical signal;

[0129] A fourth determining unit is used to determine a sensing data set according to the envelope signal, the disturbance signal and the power signal.

[0130] Optionally, the parameter corresponding to the optical fiber sensor to be tested includes: at least one of a temperature parameter, a strain parameter, a vibration parameter and a loss parameter;

[0131] The evaluation module 204 includes:

[0132] An evaluation unit is used to evaluate at least one parameter among the temperature parameter, strain parameter, vibration parameter and loss parameter corresponding to the optical fiber sensor to be tested according to at least one of the disturbance signal, the envelope signal and the power signal, and obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0133] Optionally, the evaluation unit includes:

[0134] A first acquisition subunit, used to acquire a current strength value of the disturbance signal;

[0135] a second acquisition subunit, configured to acquire an intensity change value of the disturbance signal if the current intensity value of the disturbance signal is different from the historical intensity value of the disturbance signal;

[0136] The first determining subunit is used to determine that the evaluation result of the vibration parameter is that the optical fiber sensor to be tested vibrates if the intensity change value of the disturbance signal is greater than or equal to a first preset threshold.

[0137] Optionally, the evaluation unit includes:

[0138] A third acquisition subunit, used to acquire a power change of the envelope signal and a change of a Brillouin frequency shift corresponding to the envelope signal;

[0139] A first evaluation subunit is used to evaluate the temperature parameter corresponding to the optical fiber sensor to be tested if the power change of the envelope signal is greater than or equal to a second preset threshold, and determine the evaluation result of the temperature parameter corresponding to the optical fiber sensor to be tested according to the change of the Brillouin frequency shift;

[0140] The second evaluation subunit is used to evaluate the strain parameter corresponding to the optical fiber sensor to be tested if the power change of the envelope signal is less than the second preset threshold, and determine the evaluation result of the strain parameter corresponding to the optical fiber sensor to be tested according to the change of the Brillouin frequency shift.

[0141] Optionally, the evaluation unit includes:

[0142] A fourth acquisition subunit, used to acquire a current power value of the power signal;

[0143] a fifth acquisition subunit, configured to acquire a power change value of the power signal if the current power value of the power signal is different from the historical power value of the power signal;

[0144] The second determining subunit is used to determine the loss amount corresponding to the optical fiber sensor to be tested according to the power change value of the power signal.

[0145] The above-mentioned product can execute the optical fiber sensing method based on a dual-wavelength light source provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the optical fiber sensing method based on a dual-wavelength light source.

[0146] Embodiment 3

[0147] Figure 4 A schematic diagram of the structure of an electronic device 30 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0148] like Figure 4 As shown, the electronic device 30 includes at least one processor 31, and a memory connected to the at least one processor 31, such as a read-only memory (ROM) 32, a random access memory (RAM) 33, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 31 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 32 or the computer program loaded from the storage unit 38 to the random access memory (RAM) 33. In the RAM 33, various programs and data required for the operation of the electronic device 30 can also be stored. The processor 31, ROM 32 and RAM 33 are connected to each other through a bus 34. An input / output (I / O) interface 35 is also connected to the bus 34.

[0149] A number of components in the electronic device 30 are connected to the I / O interface 35, including: an input unit 36, such as a keyboard, a mouse, etc.; an output unit 37, such as various types of displays, speakers, etc.; a storage unit 38, such as a disk, an optical disk, etc.; and a communication unit 39, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 39 allows the electronic device 30 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0150] The processor 31 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 31 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The processor 31 performs the various methods and processes described above, such as the optical fiber sensing method based on a dual-wavelength light source:

[0151] Acquire a forward sensing light signal and a local oscillator light signal set;

[0152] Inputting the forward sensing light signal into the optical fiber sensor to be tested to obtain a feedback light signal;

[0153] Determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set;

[0154] At least one parameter corresponding to the optical fiber sensor to be tested is evaluated according to the sensing data set to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested.

[0155] In some embodiments, the optical fiber sensing method based on a dual-wavelength light source can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 38. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 30 via the ROM 32 and / or the communication unit 39. When the computer program is loaded into the RAM 33 and executed by the processor 31, one or more steps of the optical fiber sensing method based on a dual-wavelength light source described above can be performed. Alternatively, in other embodiments, the processor 31 can be configured to execute the optical fiber sensing method based on a dual-wavelength light source by any other appropriate means (e.g., by means of firmware).

[0156] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0157] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0158] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0159] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0160] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0161] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0162] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0163] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fiber optic sensing method based on a dual-wavelength light source, characterized in that: include: Acquire a forward sensing light signal and a local oscillator light signal set; Inputting the forward sensing light signal into the optical fiber sensor to be tested to obtain a feedback light signal; Determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set; Evaluate at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested; The local oscillator optical signal set includes: a first local oscillator optical signal and a second local oscillator optical signal; Obtain a forward sensing light signal and a local oscillator light signal set, including: Acquire dual-wavelength optical signals; Dividing the dual-wavelength optical signal to obtain a forward sensing optical signal, a first local oscillation optical signal, and a second local oscillation optical signal; The feedback optical signal includes: a first optical signal and a second optical signal; the first optical signal includes: a Brillouin scattered optical signal and a phase-sensitive reflected optical signal; Determining a sensing data set according to the feedback optical signal and the local oscillator optical signal set includes: Determining an envelope signal according to the first local oscillator light signal and the Brillouin scattered light signal; wherein the envelope signal is a signal obtained by coupling the first local oscillator light signal and the Brillouin scattered light signal; Determining a disturbance signal according to the second local oscillator light signal and the phase-sensitive reflected light signal; wherein the disturbance signal is a signal obtained by coupling the second local oscillator light signal and the phase-sensitive reflected light signal; Determine a power signal according to the second optical signal; wherein the power signal is a signal for evaluating a loss parameter of the optical fiber sensor to be tested; determining a sensing data set according to the envelope signal, the disturbance signal and the power signal; At least one of a temperature parameter, a strain parameter, a vibration parameter, and a loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, the envelope signal, and the power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including: Obtaining a current intensity value of the disturbance signal; If the current intensity value of the disturbance signal is different from the historical intensity value of the disturbance signal, obtaining an intensity change value of the disturbance signal; If the intensity change value of the disturbance signal is greater than or equal to a first preset threshold value, determining that the evaluation result of the vibration parameter is that the optical fiber sensor to be tested vibrates; At least one of a temperature parameter, a strain parameter, a vibration parameter, and a loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, the envelope signal, and the power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including: Acquire a power variation of the envelope signal and a Brillouin frequency shift variation corresponding to the envelope signal; If the power change of the envelope signal is greater than or equal to a second preset threshold, the temperature parameter corresponding to the optical fiber sensor to be tested is evaluated, and the evaluation result of the temperature parameter corresponding to the optical fiber sensor to be tested is determined according to the change of the Brillouin frequency shift; If the power change of the envelope signal is less than the second preset threshold, the strain parameter corresponding to the optical fiber sensor to be tested is evaluated, and the evaluation result of the strain parameter corresponding to the optical fiber sensor to be tested is determined according to the change of the Brillouin frequency shift; At least one of a temperature parameter, a strain parameter, a vibration parameter, and a loss parameter corresponding to the optical fiber sensor to be tested is evaluated according to at least one of the disturbance signal, the envelope signal, and the power signal to obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested, including: Obtaining a current power value of the power signal; If the current power value of the power signal is different from the historical power value of the power signal, obtaining a power change value of the power signal; The loss amount corresponding to the optical fiber sensor to be tested is determined according to the power change value of the power signal.

2. An optical fiber sensing device based on a dual-wavelength light source, characterized in that: include: An acquisition module, used for acquiring a forward sensing light signal and a local oscillator light signal set; An input module, used for inputting the forward sensing optical signal into the optical fiber sensor to be tested to obtain a feedback optical signal; A determination module, configured to determine a sensing data set according to the feedback optical signal and the local oscillator optical signal set; An evaluation module, configured to evaluate at least one parameter corresponding to the optical fiber sensor to be tested according to the sensing data set, and obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested; The local oscillator optical signal set includes: a first local oscillator optical signal and a second local oscillator optical signal; The acquisition module includes: an acquisition unit and a division unit; The acquisition unit is used to acquire the dual-wavelength optical signal; The dividing unit is used to divide the dual-wavelength optical signal to obtain a forward sensing optical signal, a first local oscillation optical signal and a second local oscillation optical signal; The feedback optical signal includes: a first optical signal and a second optical signal; The first optical signal includes: a Brillouin scattered optical signal and a phase sensitive reflected optical signal; The determination module includes: a first determination unit, a second determination unit, a third determination unit and a fourth determination unit; a first determining unit, configured to determine an envelope signal according to the first local oscillator light signal and the Brillouin scattered light signal; wherein the envelope signal is a signal obtained by coupling the first local oscillator light signal and the Brillouin scattered light signal; a second determining unit, configured to determine a disturbance signal according to the second local oscillator light signal and the phase-sensitive reflected light signal; wherein the disturbance signal is a signal obtained by coupling the second local oscillator light signal and the phase-sensitive reflected light signal; a third determining unit, configured to determine a power signal according to the second optical signal; wherein the power signal is a signal for evaluating a loss parameter of the optical fiber sensor to be tested; a fourth determining unit, configured to determine a sensing data set according to the envelope signal, the disturbance signal, and the power signal; The evaluation module comprises an evaluation unit; The evaluation unit is used to evaluate at least one parameter among a temperature parameter, a strain parameter, a vibration parameter and a loss parameter corresponding to the optical fiber sensor to be tested according to at least one of the disturbance signal, the envelope signal and the power signal, and obtain an evaluation result of each parameter corresponding to the optical fiber sensor to be tested; The evaluation unit includes a first acquisition subunit, a second acquisition subunit and a first determination subunit; The first acquisition subunit is used to acquire a current strength value of the disturbance signal; The second acquisition subunit is configured to acquire an intensity change value of the disturbance signal if the current intensity value of the disturbance signal is different from the historical intensity value of the disturbance signal; The first determining subunit is used to determine that the evaluation result of the vibration parameter is that the optical fiber sensor to be tested vibrates if the intensity change value of the disturbance signal is greater than or equal to a first preset threshold value; The evaluation unit comprises: a third acquisition subunit, a first evaluation subunit and a second evaluation subunit; The third acquisition subunit is used to acquire the power change of the envelope signal and the change of the Brillouin frequency shift corresponding to the envelope signal; The first evaluation subunit is used to evaluate the temperature parameter corresponding to the optical fiber sensor to be tested if the power change of the envelope signal is greater than or equal to a second preset threshold, and determine the evaluation result of the temperature parameter corresponding to the optical fiber sensor to be tested according to the change of the Brillouin frequency shift; The second evaluation subunit is used to evaluate the strain parameter corresponding to the optical fiber sensor to be tested if the power change of the envelope signal is less than the second preset threshold value, and determine the evaluation result of the strain parameter corresponding to the optical fiber sensor to be tested according to the change of the Brillouin frequency shift; The evaluation unit further includes: a fourth acquisition subunit, a fifth acquisition subunit, and a second determination subunit; The fourth acquisition subunit is used to acquire the current power value of the power signal; The fifth acquisition subunit is configured to acquire a power change value of the power signal if the current power value of the power signal is different from the historical power value of the power signal; The second determining subunit is used to determine the loss amount corresponding to the optical fiber sensor to be tested according to the power change value of the power signal.

3. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to perform the optical fiber sensing method based on a dual-wavelength light source as claimed in claim 1.

4. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the optical fiber sensing method based on a dual-wavelength light source as described in claim 1 when executed.

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