Application method of frequency modulation pulse and dispersion compensation pulse compression technology in phi-otdr

Abstract

The application discloses a kind of based on frequency modulation pulse and dispersion compensation pulse compression technology in the application method of φ-OTDR, including steps S1: obtaining optical frequency domain modulation sweep pulse;Step S2: obtaining spatial resolution;Step S3: by increasing the phase delay of scattered light of optical circulator and linear chirp fiber Bragg grating and is constituted new spatial resolution.The application discloses a kind of based on frequency modulation pulse and dispersion compensation pulse compression technology in the application method of φ-OTDR, solve the problem that existing system must sacrifice sensing distance to improve spatial resolution, and the problem that pulse width is large in existing solution based on amplitude modulation pulse and matched filtering, is susceptible to Doppler effect, and matched filtering sidelobe deteriorates signal-to-noise ratio.

Description

Technical Field

[0001] This invention pertains to phase-sensitive optical time-domain reflectometers. This relates to the technical field of pulse compression technology based on frequency-modulated pulses and dispersion compensation. Application methods in the system. Background Technology

[0002] Based on phase-sensitive optical time-domain reflectometer technology The Distributed Optical Fiber Vibration Sensing System (DVS) can directly utilize existing communication optical fibers as both the signal transmission medium and the sensing unit, achieving a unified "sensing" and "transmission" function. Its distributed sensing characteristics allow it to measure and locate disturbances at any point along the laid optical fiber. Furthermore, fiber optic sensing uses light waves as the carrier and optical fiber as the transmission medium. Compared to traditional electrical sensors, fiber optic sensors offer advantages such as high measurement accuracy, resistance to electromagnetic interference, readily available infrastructure, low cost, and suitability for remote monitoring. They are widely used, particularly in intelligent transportation, pipeline transportation, geological disaster monitoring and early warning, perimeter security, and power systems.

[0003] The technology is based on the uneven stress distribution or refractive index distribution caused by impurities during the optical fiber manufacturing process. This results in Rayleigh scattering when the probe pulse light propagates through the fiber. Some of the backscattered Rayleigh light, carrying disturbance information, can continue to propagate in the opposite direction of the fiber and be detected by a photodetector. The time it takes for the backscattered light generated at different locations on the sensing fiber to return to the photodetector varies. The signal measurement time can correspond to events occurring at different locations on the fiber, thus enabling the localization of disturbance events. When an external disturbance acts on the fiber, the intensity, phase, or frequency of the scattered light changes. By demodulating the changes in various parameters of the scattered light signal, the disturbance information at the corresponding location can be obtained.

[0004] To improve While the spatial resolution of the system can reduce the probe light pulse width τ, the peak power of the scattered light received by the photodetector also decreases as the accumulation range decreases. This leads to a reduction in the system's signal-to-noise ratio and dynamic range, and a shortened sensing distance. Therefore, in long-distance sensing, the system's spatial resolution is approximately 4m to 16m. Furthermore, achieving a higher signal-to-noise ratio by reducing the pulse width while increasing the instantaneous power may result in nonlinear effects in the optical fiber.

[0005] How to solve The contradiction between the system's spatial resolution and sensing distance is This is a key area of ​​research related to the system. Therefore, further improvements are needed to address the aforementioned issues. Summary of the Invention

[0006] The main objective of this invention is to provide a pulse compression technique based on frequency-modulated pulses and dispersion compensation. The proposed method addresses the problem that existing systems must sacrifice sensing distance to improve spatial resolution, as well as the issues of large pulse widths, susceptibility to Doppler effects, and signal-to-noise ratio degradation caused by sidelobes in existing amplitude-modulated pulse (sweep pulse) and matched filtering solutions.

[0007] To achieve the above objectives, this invention provides a pulse compression technique based on frequency-modulated pulses and dispersion compensation. The application method includes the following steps:

[0008] Step S1: Obtain the optical frequency domain modulated sweep pulse. Assume that the amplitude of each frequency of the incident light is the same, the sweep rate is γ, and the sweep starting point is f0. The optical frequency domain modulated sweep pulse is represented as:

[0009] f(t) = γt + f0;

[0010]

[0011] Step S2: Obtain the spatial resolution, where:

[0012] The optical frequency increases linearly with time, and the propagation speed of the light wave at the beginning and end of the pulse is expressed as:

[0013]

[0014]

[0015] In the formula, n start and n end Let v be the effective refractive index of the light at the pulse front and end, respectively, for propagation in the optical fiber at the corresponding light frequencies. Considering the dispersion characteristics of the fiber core, we know v start <v endFurthermore, (according to the formula f(t)=γt+f0), the time for the backscattered Rayleigh light excited at various points in the fiber at the pulse front and back ends to reach the photodetector is calculated as follows:

[0016]

[0017]

[0018] The light intensity measured by the photodetector is the beat frequency information (white light interference) of the backscattered Rayleigh light within a certain range on the optical fiber. At time t, the superposition range of the backscattered Rayleigh light on the optical fiber measured by the photodetector, i.e., the spatial resolution, is:

[0019]

[0020] In the formula, z start and z end These are the front and end positions of the fiber containing the backscattered Rayleigh light, measured at time t, respectively.

[0021] Step S3: A new spatial resolution is obtained by adding a scattered light phase delay unit composed of an optical circulator and a linearly chirped fiber Bragg grating, wherein:

[0022] The time it takes for the scattered light signal from each location in the optical fiber to reach the photodetector after being compressed by a linearly chirped fiber Bragg grating is expressed as:

[0023]

[0024]

[0025] in, and The optical frequencies f corresponding to the pulse front and back ends are respectively. max and f min The time delay in a linearly chirped fiber Bragg grating is determined through the parameter design of the linearly chirped fiber Bragg grating.

[0026] make have to The spatial resolution of the system is expressed as:

[0027]

[0028] Step S4: According to the principle of interference (ignoring the DC term), the interference intensity of light of the same frequency is expressed as:

[0029]

[0030]

[0031] in, Δz is the phase difference when the scattered light excited by the incident light of frequency f and its adjacent frequency arrives at the detector; Δz is the positional interval of the scattered light excited by the incident light of frequency f and its adjacent frequency; ρ0 is the light intensity amplitude.

[0032] As a further preferred embodiment of the above technical solution, step S4 further includes:

[0033] Step S5: Vibration disturbance causes the optical fiber to produce a strain that varies periodically with the disturbance, and changes the spatial spacing between adjacent scattering points, ultimately leading to a change in the measured coherent superposition intensity of the scattered light. The vibration information is then reconstructed based on the frequency and phase information of the measured light intensity change.

[0034] As a further preferred technical solution to the above technical solution, the adjustable parameters include sweep bandwidth, sweep rate, pulse width, sweep mode (linear or nonlinear), and phase compensation (delay) mode (CFBG or adaptive phase compensation).

[0035] To achieve the above objectives, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the frequency-modulated pulse and dispersion-compensated pulse compression technology. The steps of the application method in the text.

[0036] To achieve the above objectives, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the aforementioned frequency-modulated pulse and dispersion-compensated pulse compression technology. The steps of the application method in the text. Attached Figure Description

[0037] Figure 1 This is a typical φ-OTDR system architecture diagram.

[0038] Figure 2 This is a schematic diagram of a monochromatic probe light pulse.

[0039] Figure 3 This is a schematic diagram showing the time it takes for backscattered Rayleigh light excited at various points in an optical fiber by a monochromatic light pulse to reach the photodetector.

[0040] Figure 4 This is a schematic diagram of a monochromatic frequency sweep detection light pulse.

[0041] Figure 5 This is a schematic diagram of a frequency-modulated probe light pulse.

[0042] Figure 6This is a schematic diagram showing the time (a) for the incident light pulse to reach various points in the optical fiber at the front and end, and the time (b) for the excited backscattered Rayleigh light to reach the photodetector.

[0043] Figure 7 This is a numerical calculation result of the light field distribution inside a linear chirped Bragg grating.

[0044] Figure 8 This is a schematic diagram of a high spatial resolution distributed optical fiber vibration sensing system based on wavelength-modulated swept pulses.

[0045] Figure 9 This is a schematic diagram showing the time it takes for backscattered Rayleigh light excited at various points in the optical fiber to reach the photodetector after CFBG compression.

[0046] Figure 10 yes Flowchart of the system's sensing principle. Detailed Implementation

[0047] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0048] In a preferred embodiment of the present invention, those skilled in the art should note that the present invention relates to... These can be considered existing technology.

[0049] Preferred embodiment.

[0050] Typical System such as Figure 1 As shown, A monochromatic light source emits continuous light, which is then modulated to output nanosecond-level light pulses as probe light that enters the sensing fiber. Due to minute refractive index inhomogeneities and impurity ions present during the fiber's manufacturing process, Rayleigh scattering occurs upon the probe light pulse entering the fiber. Part of the backscattered Rayleigh light propagates along the fiber towards the light source (reflected signal) and is detected by a photodetector via an optical circulator. The phase of the scattered light varies at different locations within the fiber and is also related to the strain experienced by the fiber. Let the probe light have a frequency of f. c If a monochromatic light has a pulse width of τ and an amplitude of E0, then the probe light pulse can be expressed as:

[0051]

[0052] Where t is the pulse incident time; To detect the initial phase of light at various points in the optical fiber, the time-frequency power spectrum, power spectral density, and time-frequency spectrum of the light pulse are measured. Figure 2 As shown.

[0053] Depend on Figure 2 (a) It can be seen that the time difference between the beginning and end of the pulse entering the sensing fiber is one pulse width. The time when the backscattered Rayleigh light generated by the beginning and end of the pulse in the fiber enters the photodetector can be expressed as follows:

[0054]

[0055]

[0056] In the formula, z represents the fiber position coordinates; v g =c / n eff ;n eff is the effective refractive index of the light in the sensing fiber; c is the speed of light in a vacuum. Figure 3 The time it takes for the scattered light from the front and rear ends of the probe beam to reach the photodetector at various points in the optical fiber, plotted according to the above formula, is given by... Figure 3 It can be seen that at time t, the photodetector measures the z-axis on the sensing fiber. start To z end The intensity of the interference superposition of scattered light. When a disturbance event acts on this location, the phase difference of the scattered light will change, causing the intensity of the interference light to change with the disturbance. Based on the light intensity information measured by the photodetector, the frequency, amplitude, and other information of the disturbance can be determined, realizing distributed vibration sensing and positioning. The range of the sensing fiber in which the scattered light participating in the interference is located, i.e. Spatial resolution can be expressed as:

[0057]

[0058] It can be seen that, based on monochromatic light pulses The system's spatial resolution is half a pulse width. Taking a typical probe light pulse width of 20 ns as an example, its corresponding spatial resolution is approximately 4 m.

[0059]

[0060] From the formula and formula It can be seen that the light intensity information measured by the photodetector is the result of the joint interference of backscattered Rayleigh light within half a pulse width, and its peak power is the sum of the scattered light power at all scattering points within half a pulse width.

[0061]

[0062] Where α is the backscattering Rayleigh coefficient of the sensing fiber. From the formula... It is clear that in order to improve The spatial resolution of the system can reduce the probe light pulse width τ, but the peak power of the scattered light received by the photodetector also decreases as the accumulation range decreases, leading to a reduction in the system's signal-to-noise ratio and dynamic range, and a shortened sensing distance. Therefore, in long-distance sensing, the system's spatial resolution is approximately 4m to 16m. Furthermore, achieving a higher signal-to-noise ratio by simultaneously reducing the pulse width and increasing the instantaneous power may lead to nonlinear effects in the optical fiber. How can this be addressed? The contradiction between the system's spatial resolution and sensing distance is Key areas of research related to systems.

[0063] Referring to radar measurement technology, pulse compression technology based on swept-frequency pulses and matched filtering is applied as a scheme to improve spatial resolution under long measurement distance conditions. The system achieved a spatial resolution of 30 cm over a measurement distance of 19.8 km.

[0064] Taking a monochromatic linear sweep pulse as an example, its time power spectrum, power spectral density, and time spectrum are as follows: Figure 4 As shown. By Figure 4 (a) It can be seen that the swept pulse modulates the amplitude of the incident light power based on the ordinary single pulse. From formula (1), the incident light pulse after the swept pulse modulation can be expressed as:

[0065]

[0066] Where κ is the linear sweep rate. The electrical signal acquired by the corresponding balanced detector can be expressed as:

[0067]

[0068] h(t)=a(t)r(t)exp(-i2πf c t);

[0069] Where a(t) is the fiber attenuation function; r(t) is the corresponding Rayleigh scattering coefficient. Inputting the signal into a matched filter outputs a pulse-compressed signal.

[0070]

[0071] The spatial resolution of the electrical signal after matched filtering is defined as the 3dB bandwidth of the main lobe:

[0072]

[0073] Where B represents the frequency sweep range of the probe light pulse. From the above equation, it can be seen that based on the frequency sweep pulse and matched filtering... The spatial resolution of the system is inversely proportional to the frequency sweep range, effectively solving the problem that the spatial resolution of ordinary probe light pulses is affected by the pulse width.

[0074] As can be seen from the above formulas, the pulse compression principle based on radar wave detection technology is essentially the suppression of noise in the detection electrical signal and the amplification of the effective signal. This belongs to signal processing in the electrical domain. Matched filtering introduces a series of sidelobes, leading to a certain degree of signal-to-noise ratio reduction. Furthermore, in applications, the pulse width of the swept pulse needs to reach the micrometer level, far exceeding that of traditional methods. To prevent interference between scattered signals, only a single nanosecond pulse is allowed to pass through the sensing fiber at any given time. For a sensing fiber of length L, the minimum pulse repetition period of the system is:

[0075]

[0076] According to the Nyquist sampling theorem, the maximum vibration response frequency of the system is:

[0077]

[0078] Therefore, this technology will significantly reduce the frequency response bandwidth of the system.

[0079] Based on the formulas for the electrical signals acquired by the balanced detector and the formulas for the output pulse compression signal, since matched filtering relies on the known frequency of the scattered light from the incident pulse, for high-speed moving objects, the spatial frequency of the backscattered Rayleigh signal caused by the Doppler effect does not match the frequency of the swept pulse modulation and the frequency of the matched filter signal. It will also reduce the pulse compression effect.

[0080] To solve the traditional The system's contradiction between spatial resolution and sensing distance, and the limitations of pulse compression technology based on matched filtering. To address issues such as reduced response bandwidth and susceptibility to the Doppler effect in the system, this invention proposes a distributed optical fiber vibration sensing system with high spatial resolution and high response bandwidth based on optical frequency modulated sweep pulses, as well as its application method.

[0081] This invention discloses a pulse compression technique based on frequency-modulated pulses and dispersion compensation. The application method in, through Figure 8 The implementation of the high spatial resolution distributed fiber optic vibration sensing system based on wavelength-modulated swept pulses, as shown, includes the following steps:

[0082] Step S1: (A distributed fiber optic vibration sensing system based on high spatial resolution and high response bandwidth of frequency-modulated pulses uses wavelength (optical frequency) modulated sweep pulses. The pulse time power spectrum, power spectral density, and time spectrum are as follows...) Figure 5 As shown. Pulse instantaneous power and traditional The system has identical monochromatic light pulses, a power spectral density distribution within a certain bandwidth, and a linearly varying light frequency within a single pulse time, with each moment being monochromatic light. A frequency-domain modulated sweep pulse is obtained. Assume the incident light has the same amplitude at all frequencies, a sweep rate of γ, and a sweep starting point of f0. (According to the formula...) and The sweep pulse of optical frequency domain modulation is represented as:

[0083] f(t) = γt + f0;

[0084]

[0085] Step S2: Obtain the spatial resolution, where:

[0086] Depend on Figure 5 (c) It can be seen that the optical frequency increases linearly with time, and the optical wave propagation speed at the beginning and end of the pulse can be expressed as:

[0087]

[0088]

[0089] In the formula, n start and n end Let v be the effective refractive index of the light at the pulse front and end, respectively, for propagation in the optical fiber at the corresponding light frequencies. Considering the dispersion characteristics of the fiber core, we know v start <v end Furthermore, (according to the formula f(t)=γt+f0), the time for the backscattered Rayleigh light excited at various points in the fiber at the pulse front and back ends to reach the photodetector is calculated as follows:

[0090]

[0091]

[0092] The light intensity measured by the photodetector is the beat frequency information (white light interference) of the backscattered Rayleigh light within a certain range on the optical fiber. Figure 6 According to the formula (A schematic diagram showing the arrival times of scattered light at various points on the optical fiber to the photodetector) At time t, the superposition range of the backscattered Rayleigh light on the optical fiber measured by the photodetector, i.e., the spatial resolution, is:

[0093]

[0094] In the formula, z start and z end These are the front and rear ends of the fiber containing the backscattered Rayleigh light, measured at time t (using the formula...). It is known that due to the dispersion effect of frequency-modulated pulses, the pulse undergoes time-domain (or spatial-domain) compression during transmission, increasing the frequency components of the power spectral density. This leads to a decrease in the spatial resolution of the system over time. For incident probe light pulses, the sweep bandwidth should not be too large or the sensing fiber too long; otherwise, without considering transmission loss, the total pulse energy remains constant, but during pulse transmission, dispersion may cause excessive instantaneous power, resulting in nonlinear effects. For backscattered Rayleigh light, since the power of the scattered light is much lower than that of the incident light, nonlinear effects are almost impossible.

[0095] (During the duration of the probe light pulse, the light frequency changes linearly with time; therefore, each frequency is distinguishable in time (and space). Linearly chirped fiber Bragg gratings (CFBGs) exhibit periodic refractive index modulation with a modulation period that changes linearly with space. For example...) Figure 7 As shown, within the characteristic wavelength (frequency) bandwidth of a grating, light of different frequencies reflects at different positions within the grating, and therefore is often used to achieve dispersion compensation.

[0096] Step S3: (The structure of a high spatial resolution distributed fiber optic vibration sensing system based on wavelength-modulated swept pulses is as follows) Figure 8 As shown. Compared to traditional The system adds a scattered light phase delay unit composed of an optical circulator and a CFBG (Cellular Fiber Bragg Grating) before the photodetector. Because the scattered light frequency differs at different positions of the probe light pulse, the phase delay in the CFBG varies, allowing for further compression of the scattered light signal in the time domain to reduce spatial resolution. A new spatial resolution is achieved by adding a scattered light phase delay unit composed of an optical circulator and a linearly chirped fiber Bragg grating, where:

[0097] The time it takes for the scattered light signal from each location in the optical fiber to reach the photodetector after being compressed by a linearly chirped fiber Bragg grating is expressed as:

[0098]

[0099]

[0100] in, and The optical frequencies f corresponding to the pulse front and back ends are respectively. max and f min The time delay in a linearly chirped fiber Bragg grating is determined through the parameter design of the linearly chirped fiber Bragg grating.

[0101] make have to (like Figure 9 As shown), the spatial resolution of the system is expressed as:

[0102]

[0103] From the formula It can be seen that, under a specific pulse width, the spatial resolution of the system is related to the optical frequency scanning bandwidth and the delay of CFBG. Compared to traditional... The system and pulse compression technology based on matched filtering: The high spatial resolution distributed fiber optic vibration sensing system based on wavelength modulation swept pulses achieves pulse compression in the optical domain through the dispersion compensation principle of CFBG. The pulse compression process does not generate electrical signal sidelobes, resulting in a higher signal-to-noise ratio. The adjustable parameters of the system include swept bandwidth, swept rate, pulse width, swept mode (linear or nonlinear), and phase compensation (delay) mode (CFBG or adaptive phase compensation), etc. The system has a high degree of design freedom and many optimizable parameters. Through pulse compression in the optical domain, smaller spatial resolution can be achieved under nanosecond-level pulses, with a small pulse repetition period and a large system vibration response bandwidth.

[0104] Step S4: (Based on frequency modulation pulse) In the system, the photodetector measures the superposition of backscattered Rayleigh signals within a section of the sensing fiber (including all frequency components of the incident light pulse). According to the interference principle (ignoring the DC term), the interference intensity of light of the same frequency is expressed as:

[0105]

[0106]

[0107] in, Δz is the phase difference when the scattered light excited by the incident light of frequency f and its adjacent frequency arrives at the detector; Δz is the positional interval of the scattered light excited by the incident light of frequency f and its adjacent frequency; ρ0 is the light intensity amplitude.

[0108] Specifically, after step S4, the following steps are also included:

[0109] Step S5: Vibration disturbance causes the optical fiber to produce a strain that varies periodically with the disturbance, and changes the spatial spacing between adjacent scattering points, ultimately leading to a change in the measured coherent superposition intensity of the scattered light. The vibration information is then reconstructed based on the frequency and phase information of the measured light intensity change.

[0110] More specifically, the adjustable parameters include sweep bandwidth, sweep rate, pulse width, sweep mode (linear or nonlinear), and phase compensation (delay) mode (CFBG or adaptive phase compensation).

[0111] This invention also discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the frequency-modulated pulse and dispersion-compensated pulse compression technology. The steps of the application method in the text.

[0112] This invention also discloses a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the aforementioned frequency-modulated pulse and dispersion-compensated pulse compression technology. The steps of the application method in the text.

[0113] It is worth mentioning that the technical features such as #imgpt87# involved in this patent application should be regarded as prior art. The specific structure, working principle and possible control methods and spatial arrangement methods of these technical features can be adopted by conventional choices in the field, and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0114] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A method for applying frequency-modulated pulse and dispersion-compensated pulse compression technology in φ-OTDR, characterized in that, Includes the following steps: Step S1: Obtain the frequency-sweeping pulse modulated by the optical frequency domain. Assume that the amplitude of each frequency of the incident light is the same, and the sweep rate is... γ The starting point of the frequency sweep is f 0. The sweep pulse of optical frequency domain modulation is represented as: ； ； Step S2: Obtain the spatial resolution, where: The optical frequency increases linearly with time, and the propagation speed of the light wave at the beginning and end of the pulse is expressed as: ； ； In the formula, n start and n end Let be the effective refractive indices of the light frequencies corresponding to the pulse front and rear ends, respectively, propagating in the optical fiber. The time it takes for the backscattered Rayleigh light excited at various points in the optical fiber at the pulse front and rear ends to reach the photodetector is calculated as follows: ； ； The light intensity measured by the photodetector is the beat frequency information of the backscattered Rayleigh light within a certain range on the optical fiber. t At any given time, the spatial resolution is the range of superposition of the backscattered Rayleigh light on the optical fiber as measured by the photodetector. ； In the formula, z start and z end They are respectively in t The position of the backscattered Rayleigh light at the beginning and end of the fiber measured at time t; Step S3: A new spatial resolution is obtained by adding a scattered light phase delay unit composed of an optical circulator and a linearly chirped fiber Bragg grating, wherein: The time it takes for the scattered light signal from each location in the optical fiber to reach the photodetector after being compressed by a linearly chirped fiber Bragg grating is expressed as: ； in, and These are the optical frequencies corresponding to the pulse front and back ends, respectively. f max and f min The time delay in a linearly chirped fiber Bragg grating is determined through the parameter design of the linearly chirped fiber Bragg grating. make ,have to The spatial resolution of the system is expressed as: ； Step S4: According to the principle of interference, the intensity of interference light of the same frequency is expressed as: ； ； in, φ For frequency f The phase difference when the scattered light excited by the incident light at an adjacent frequency reaches the detector; Δ z For frequency f The positional interval of the scattered light excited by the incident light of its adjacent frequency; ρ 0 represents the light intensity amplitude.

2. The application method of φ-OTDR based on frequency-modulated pulse and dispersion-compensated pulse compression technology according to claim 1, characterized in that, Step S4 is followed by: Step S5: Vibration disturbance causes the optical fiber to produce a strain that varies periodically with the disturbance, and changes the spatial spacing between adjacent scattering points, ultimately leading to a change in the measured coherent superposition intensity of the scattered light. The vibration information is then reconstructed based on the frequency and phase information of the measured light intensity change.

3. The application method of φ-OTDR based on frequency-modulated pulse and dispersion-compensated pulse compression technology according to claim 1, characterized in that, Adjustable parameters include sweep bandwidth, sweep rate, pulse width, sweep mode, and phase compensation mode.

4. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method for applying frequency-modulated pulse and dispersion-compensated pulse compression technology in φ-OTDR as described in any one of claims 1 to 3.

5. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method for applying frequency-modulated pulse and dispersion-compensated pulse compression technology in φ-OTDR as described in any one of claims 1 to 3.

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