Wavelength demodulation method, module, device and medium for long-distance fiber grating array

Abstract

The present application discloses a wavelength demodulation method, module, device and medium for a long-distance fiber grating array. The method determines the time to start collecting the required grating signal by performing data analysis on a first grating signal sample, thereby correspondingly determining a reasonable delay time. On the one hand, it is possible to avoid invalid grating signal collection processes when performing wavelength demodulation on the long-distance fiber grating array, thereby correspondingly increasing the demodulation frequency; on the other hand, by determining the wavelength range of the first grating signal sample and then determining the first sweep frequency range of the system light source in combination with a reasonable preset fluctuation range, it is possible to narrow the sweep frequency wavelength range when performing wavelength demodulation on the long-distance fiber grating array, thereby increasing the demodulation frequency.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to a wavelength demodulation method, module, device and medium for a long-distance optical fiber grating array. Background Art

[0002] The fiber grating sensing system is a sensing system that uses light as a carrier and optical fiber as a medium. In addition to the advantages of small size, light weight, wide bandwidth, high sensitivity, strong anti-electromagnetic interference and corrosion resistance, it is also unaffected by light power fluctuations, integrates sensing and transmission, is easy to manufacture and can be buried inside materials to achieve the measurement of stress, strain, temperature and other physical quantities. Compared with traditional electrical sensing systems, this technology has more advantages in harsh environments such as strong electromagnetic interference, flammable and explosive or thermal vacuum.

[0003] However, the demodulation frequency of traditional fiber grating array wavelength demodulation technology is greatly limited by the detection distance and the scanning range of the light source. In particular, there is often no machine room to place equipment around bridges and tracks. The demodulation equipment often needs to be placed several kilometers away, and high-speed demodulation above 100 Hz cannot be achieved in such a long link.

[0004] Therefore, in the process of wavelength demodulation in the prior art, there is a problem that the demodulation frequency is limited due to the long-distance transmission link and the large sweep wavelength range. Summary of the invention

[0005] In view of this, it is necessary to provide a wavelength demodulation method, module, device and medium for a long-distance fiber grating array to solve the problem in the prior art that, during the wavelength demodulation process, the demodulation frequency is limited due to the long-distance transmission link and the large scanning wavelength range.

[0006] In order to solve the above problems, the present invention provides a wavelength demodulation method for a long-distance fiber grating array, comprising:

[0007] Acquire the first time when the first grating signal sample is collected;

[0008] Determine the delay time based on the first time;

[0009] Acquire a first wavelength range of a first grating signal sample;

[0010] Determining a first frequency sweep range of the system light source according to the first wavelength range and the preset fluctuation range;

[0011] When wavelength demodulation is performed on a long-distance fiber grating array, after an interval delay time, the system light source collects wavelengths within a first frequency sweep range to perform wavelength demodulation.

[0012] Further, obtaining the first time of collecting the first grating signal sample includes:

[0013] Acquire the transmission link length of the first grating sensor;

[0014] According to the transmission link length, a first time when the first grating sensor collects the first grating signal sample is determined.

[0015] Further, determining the delay time according to the first time includes:

[0016] Set the delay factor;

[0017] The delay time is determined by taking the product according to the first time and the delay coefficient.

[0018] Further, obtaining a first wavelength range of the first grating signal sample includes:

[0019] obtaining a wavelength sample of the first grating signal sample;

[0020] According to the wavelength samples, a first wavelength range of the first grating signal samples is determined by a centroid peak finding algorithm.

[0021] Further, according to the first wavelength range and the preset fluctuation range, determining the first frequency sweep range of the system light source includes:

[0022] Determine a first wavelength maximum value and a first wavelength minimum value according to the first wavelength range;

[0023] Determine the maximum value of the frequency sweep wavelength according to the first wavelength maximum value and the preset fluctuation range;

[0024] Determine the minimum value of the frequency sweep wavelength according to the first wavelength minimum value and the preset fluctuation range;

[0025] A first frequency sweep range of the system light source is determined according to the maximum value and the minimum value of the frequency sweep wavelength.

[0026] Further, when wavelength demodulation is performed on a long-distance fiber grating array, after an interval delay time, the system light source collects wavelengths within the first frequency sweep range to perform wavelength demodulation, including:

[0027] Obtaining linear frequency sweep light of the system light source;

[0028] When wavelength demodulation is performed on a long-distance fiber grating array, a linear frequency sweep light is modulated after an interval delay time to generate a frequency sweep pulse light;

[0029] The frequency sweep pulse light within the first frequency sweep range is reflected by the grating array to form a first OTDR curve of the grating;

[0030] Performing signal conversion on the first OTDR curve to obtain an electrical signal;

[0031] The electrical signal is wavelength-demodulated to determine a demodulated signal.

[0032] Furthermore, the frequency sweep pulse light within the first frequency sweep range is reflected by the grating array to form a first OTDR curve of the grating, and further includes:

[0033] Determining a second wavelength range according to the first OTDR curve;

[0034] Determining a second frequency sweep range of the system light source according to the second wavelength range and the preset fluctuation range;

[0035] The swept frequency pulse light within the second swept frequency range is reflected by the grating array to form a second OTDR curve of the grating.

[0036] In order to solve the above problems, the present invention further provides a wavelength demodulation module of a long-distance fiber grating array, comprising:

[0037] A first time acquisition unit, used to acquire a first time when a first grating signal sample is collected;

[0038] A delay time determination unit, used to determine the delay time according to the first time;

[0039] A first wavelength range acquisition unit, used to acquire a first wavelength range of a first grating signal sample;

[0040] A first frequency sweep range determining unit, used to determine a first frequency sweep range of the system light source according to the first wavelength range and a preset fluctuation range;

[0041] The wavelength demodulation unit is used for, when wavelength demodulation is performed on a long-distance fiber grating array, after an interval delay time, the system light source collects the wavelength within the first frequency sweep range to perform wavelength demodulation.

[0042] In order to solve the above problems, the present invention further provides a wavelength demodulation device, comprising:

[0043] A linear frequency-sweep light acquisition module, used to acquire the linear frequency-sweep light of the system light source;

[0044] A swept frequency pulse light generation module is used to modulate the linear swept frequency light after an interval delay time to generate a swept frequency pulse light when wavelength demodulation is performed on a long-distance fiber grating array;

[0045] A first OTDR curve acquisition module, used for forming a first OTDR curve of the grating by reflecting the swept frequency pulse light in the first swept frequency range through the grating array;

[0046] An electrical signal acquisition module, used for performing signal conversion on the first OTDR curve to obtain an electrical signal;

[0047] The demodulation signal determination module is used to perform wavelength demodulation on the electrical signal and determine the demodulation signal.

[0048] In order to solve the above problems, the present invention also provides a computer-readable storage medium, which stores computer program instructions. When the computer program instructions are executed by a computer, the computer executes the wavelength demodulation method of the long-distance fiber grating array as described above.

[0049] The beneficial effects of adopting the above technical solution are as follows: the present invention provides a wavelength demodulation method, module, device and medium for a long-distance fiber grating array. The method determines the time to start collecting the required grating signal by performing data analysis on the first grating signal sample, thereby correspondingly determining a reasonable delay time. On the one hand, it can avoid invalid grating signal collection processes when performing wavelength demodulation on the long-distance fiber grating array, and correspondingly increase the demodulation frequency; on the other hand, by determining the wavelength range of the first grating signal sample and then determining the first sweep frequency range of the system light source in combination with a reasonable preset fluctuation range, it is possible to reduce the sweep frequency wavelength range when performing wavelength demodulation on the long-distance fiber grating array, thereby increasing the demodulation frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic flow chart of an embodiment of a wavelength demodulation method for a long-distance fiber grating array provided by the present invention;

[0051] Figure 2 A schematic diagram of a flow chart of an embodiment of determining a first frequency sweep range of a system light source provided by the present invention;

[0052] Figure 3 A schematic diagram of a process for demodulating the wavelength of a long-distance fiber grating array provided by the present invention;

[0053] Figure 4 A schematic diagram of a flow chart of an embodiment of adjusting the sweep frequency range provided by the present invention;

[0054] Figure 5 A schematic diagram of the results of an embodiment of wavelength demodulation provided by the present invention;

[0055] Figure 6 A schematic diagram of the result of adjusting the sweep frequency range according to an embodiment of the present invention;

[0056] Figure 7 A schematic structural diagram of an embodiment of a wavelength demodulation module for a long-distance fiber grating array provided by the present invention;

[0057] Figure 8This is a schematic structural diagram of an embodiment of a wavelength demodulation device provided by the present invention. DETAILED DESCRIPTION

[0058] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0059] Before describing the embodiments, the OTDR and wavelength demodulation technologies are first described:

[0060] OTDR (optical time-domain reflectometer) is an instrument that analyzes the measurement curve to understand the uniformity, defects, breaks, joint coupling and other properties of optical fibers. It is made based on the backscattering and Fresnel reverse principles of light, and uses the backscattered light generated when light propagates in the optical fiber to obtain attenuation information. It can be used to measure optical fiber attenuation, joint loss, optical fiber fault point location, and understand the loss distribution along the length of the optical fiber. It is an indispensable tool in optical cable construction, maintenance and monitoring.

[0061] Fiber Bragg grating array wavelength demodulation technology is one of the key technologies in fiber Bragg grating array sensing systems. It can encode the wavelength of the sensed temperature, stress and strain information and perform linear demodulation. The system is not affected by the strength attenuation caused by link loss and device aging, and has been widely used. With the continuous expansion of application scenarios, the frequency requirements for fiber Bragg grating array wavelength demodulation systems are gradually increasing. In particular, when monitoring the stress and strain caused by vehicles passing through bridges, tracks, etc., a demodulation frequency of at least 100Hz and a scanning range of 6nm (10pm scanning step) are required to more realistically restore the dynamic strain generated by the vehicle.

[0062] It should be noted that the maximum link length L that the system can demodulate is determined by the following formula:

[0063]

[0064] Where v is the speed of light propagating in the optical fiber, which is generally 2.0×10 8 m / s; f is the system demodulation frequency; n is the number of scans.

[0065] In addition, the amount of data N transmitted per second by the system is determined by the following formula:

[0066]

[0067] Where F is the system sampling rate, B is the number of bytes per sampling point;

[0068] When f=100 Hz, n=600 (6 nm range, 10 pm step), F is 200 M / s, B is 2 Byte, L=1.66 km, N=400 M / s.

[0069] At present, the demodulation frequency of traditional fiber grating array wavelength demodulation technology is greatly limited by the detection distance and the scanning range of the light source. In particular, there is often no machine room to place equipment around bridges and tracks. The demodulation equipment often needs to be placed several kilometers away, and high-speed demodulation above 100 Hz cannot be achieved in such a long link.

[0070] Therefore, in the process of wavelength demodulation in the prior art, there is a problem that the demodulation frequency is limited due to the long-distance transmission link and the large sweep wavelength range.

[0071] In order to solve the above problems, the present invention provides a wavelength demodulation method, module, device and medium for a long-distance fiber grating array, which are described in detail below.

[0072] like Figure 1 As shown, Figure 1 A schematic flow chart of an embodiment of a wavelength demodulation method for a long-distance fiber grating array provided by the present invention includes:

[0073] Step S101: Acquire the first time when the first grating signal sample is collected.

[0074] Step S102: Determine a delay time according to the first time.

[0075] Step S103: Acquire a first wavelength range of a first grating signal sample.

[0076] Step S104: determining a first frequency sweep range of the system light source according to the first wavelength range and the preset fluctuation range.

[0077] Step S105: when wavelength demodulation is performed on the long-distance fiber grating array, after the interval delay time, the system light source collects wavelengths within the first frequency sweep range to perform wavelength demodulation.

[0078] In this embodiment, firstly, according to the collection situation of the first grating signal sample, the first time when the first grating signal sample is collected is determined, that is, the time when the first grating signal is collected is determined; secondly, a reasonable delay time is correspondingly determined according to the first time, so as to avoid an invalid grating signal collection process; then, it is necessary to perform statistics on the collected first grating signal samples to determine the first wavelength range of the first grating signal samples; next, according to the first wavelength range, the first frequency sweep range of the system light source is determined in combination with a preset fluctuation range; finally, when wavelength demodulation is performed on a long-distance fiber grating array, after the interval delay time, the system light source collects wavelengths within the first frequency sweep range for wavelength demodulation.

[0079] It can be understood that in this embodiment, on the one hand, by performing data analysis on the first grating signal sample, the time to start collecting the required grating signal is determined, thereby correspondingly determining a reasonable delay time, thereby avoiding invalid grating signal collection processes when wavelength demodulating the long-distance fiber grating array, and correspondingly increasing the demodulation frequency; on the other hand, by performing data statistics on the collected first grating signal samples, its wavelength range is determined, and then the first sweep frequency range of the system light source is determined in combination with a reasonable preset fluctuation range, thereby reducing the sweep frequency wavelength range when wavelength demodulating the long-distance fiber grating array, thereby increasing the demodulation frequency.

[0080] As a preferred embodiment, in step S101, in order to obtain the first time when the first grating signal sample is collected, first, the transmission link length of the first grating sensor is obtained, that is, the distance between the position of the first grating sensor in the link and the light source is determined; then, based on the transmission link length, the first time when the first grating sensor collects the first grating signal sample is determined.

[0081] In a specific embodiment, first, the sampling coordinates of each grating in space are obtained, denoted as Φ0...Φ n , where Φ0 is the sampling coordinate closest to the light source; then, the transmission link length of the first grating sensor is determined according to the transmission link length formula, where the transmission link length formula is:

[0082]

[0083] Among them, l0 is the length of the transmission link, v is the speed of light propagation in the optical fiber, Φ0 is the sampling coordinate from the light source, and F is the system sampling frequency.

[0084] Generally, v is taken as 2.0×10 8 m / s, and the value of F is 200MHz.

[0085] Furthermore, after determining the transmission link length, it is also necessary to determine the first time when the first grating sensor collects the first grating signal sample according to the first time formula, wherein the first time formula is:

[0086]

[0087] Among them, t0 is the first time, v is the speed of light propagation in the optical fiber, Φ0 is the sampling coordinate from the light source, and F is the system sampling frequency.

[0088] As a preferred embodiment, in step S102, after determining the first time, in order to avoid the problem of inaccurate grating signal acquisition caused by directly delaying the first time due to low accuracy of the collected first time due to system errors and the like, it is also necessary to set a delay coefficient, and then determine the delay time by taking the product of the first time and the delay coefficient.

[0089] As a preferred embodiment, the formula for determining the delay time is:

[0090] t d =kt0

[0091] Among them, t d is the delay time, k is the delay coefficient, and t0 is the first time.

[0092] In a specific embodiment, the delay coefficient k takes a value of 0.95, which can not only make the delay time as long as possible, but also ensure the accuracy of the acquisition time, and avoid the acquisition time being too late, resulting in incomplete grating signals.

[0093] As a preferred embodiment, in step S103, in order to obtain the first wavelength range of the first grating signal sample, first, a wavelength sample of the first grating signal sample is obtained; then, based on the wavelength sample, the first wavelength range of the first grating signal sample is determined by a centroid peak finding algorithm.

[0094] In a specific embodiment, the sampling coordinates of each grating in space are Φ0...Φ n The data of all scanned wavelengths at the locations are spliced, and then the central wavelength values ​​of all gratings are obtained by the centroid peak search algorithm, which are recorded as λ0…λ n , where the maximum wavelength is denoted as λ max , the minimum wavelength is denoted as λ min , that is, the first wavelength range is determined according to the maximum wavelength and the minimum wavelength.

[0095] As a preferred embodiment, in step S104, after determining the first wavelength range, if the actual frequency sweep range is determined directly based on the first wavelength range, there may be a problem that the actual frequency sweep wavelength fluctuates and does not completely overlap with the wavelength range of the first grating signal sample, resulting in a problem that the frequency sweep range is too small. Therefore, in order to determine the first frequency sweep range of the system light source, as Figure 2 As shown, Figure 2 A schematic diagram of a flow chart of an embodiment of determining a first frequency sweep range of a system light source provided by the present invention includes:

[0096] Step S141: determining a first wavelength maximum value and a first wavelength minimum value according to the first wavelength range.

[0097] Step S142: determining the maximum value of the frequency sweep wavelength according to the first wavelength maximum value and the preset fluctuation range.

[0098] Step S143: determining a minimum value of the frequency sweep wavelength according to the first minimum value of the wavelength and a preset fluctuation range.

[0099] Step S144: determining a first frequency sweep range of the system light source according to the maximum value and the minimum value of the frequency sweep wavelength.

[0100] In this embodiment, by setting a preset fluctuation range, the maximum value of the first wavelength is appropriately amplified to obtain the maximum value of the swept wavelength; the minimum value of the first wavelength is appropriately reduced to obtain the minimum value of the swept wavelength; thereby, the first swept range finally determined is appropriately amplified on the basis of the first wavelength range, so that in the process of wavelength demodulation, when the swept wavelength fluctuates to a certain extent compared with the wavelength in the first grating signal sample, it can be better handled to avoid omissions and ensure the accuracy of wavelength demodulation.

[0101] In a specific embodiment, the preset fluctuation range is 0.2 nm, that is, for the first wavelength range obtained, a total of 0.4 nm of the sweep frequency range is added. Since a large wavelength change will not occur within a certain period of time during the wavelength demodulation process, the integrity of the wavelength demodulation process can be guaranteed.

[0102] Furthermore, in order to ensure the accuracy of the first frequency sweep range, the maximum value and the minimum value of the wavelength in the wavelength demodulation process may be acquired in real time, thereby achieving real-time adjustment of the frequency sweep range.

[0103] As a preferred embodiment, in step S105, in order to perform wavelength demodulation on a long-distance fiber grating array, as Figure 3 As shown, Figure 3 A schematic diagram of a process for demodulating a long-distance fiber grating array wavelength according to an embodiment of the present invention includes:

[0104] Step S151: Acquire linear frequency-sweep light of the system light source.

[0105] Step S152: when wavelength demodulation is performed on the long-distance fiber grating array, after an interval delay time, the linear frequency-sweep light is modulated to generate frequency-sweep pulse light.

[0106] Step S153: The frequency-sweeping pulse light within the first frequency-sweeping range is reflected by the grating array to form a first OTDR curve of the grating.

[0107] Step S154: performing signal conversion on the first OTDR curve to obtain an electrical signal.

[0108] Step S155: perform wavelength demodulation on the electrical signal to determine a demodulated signal.

[0109] In this embodiment, first, a swept-frequency light with a linear distribution of wavelength and time emitted by a system light source is obtained; then, in the process of wavelength demodulation of a long-distance fiber grating array, the linear swept-frequency light is modulated after an interval delay time to generate a swept-frequency pulse light, that is, the linear swept-frequency light is modulated again after the delay time, thereby reducing invalid modulation actions; next, the swept-frequency pulse light within a first sweep-frequency range is reflected by the grating array to form a first OTDR curve of the grating, that is, the swept-frequency pulse light can only be reflected by the grating array when it is within the first sweep-frequency range, thereby obtaining a first OTDR curve with information; further, the first OTDR curve is signal converted to obtain an electrical signal; finally, the electrical signal is wavelength demodulated to determine a demodulated signal.

[0110] In this embodiment, by modulating the linear frequency sweeping light after the interval delay time, invalid modulation actions are reduced; by setting the first frequency sweeping range, the grating array can only reflect the frequency sweeping pulse light within the first frequency sweeping range, thereby narrowing the frequency sweeping range and effectively improving the demodulation frequency of the wavelength demodulation process.

[0111] As a preferred embodiment, in step S153, in order to adjust the first frequency sweep range in real time, as shown in FIG. Figure 4 As shown, Figure 4 A flow chart of an embodiment of adjusting the sweep frequency range provided by the present invention includes:

[0112] Step S1531: Determine a second wavelength range according to the first OTDR curve.

[0113] Step S1532: Determine a second frequency sweep range of the system light source according to the second wavelength range and the preset fluctuation range.

[0114] Step S1533: The frequency-sweeping pulse light within the second frequency-sweeping range is reflected by the grating array to form a second OTDR curve of the grating.

[0115] In the present embodiment, first, for the acquired first OTDR curve, the maximum wavelength and the minimum wavelength are acquired in real time to determine the second wavelength range; then, according to the second wavelength range and the preset fluctuation range, the range is expanded to determine the second frequency sweeping range of the system light source; finally, the frequency sweeping pulse light within the second frequency sweeping range is reflected by the grating array to form the second OTDR curve of the grating.

[0116] In this embodiment, the maximum wavelength and the minimum wavelength in the wavelength demodulation process are obtained in real time, and the frequency sweep range of the system light source is adjusted in real time in combination with a preset fluctuation range, thereby avoiding incomplete wavelength demodulation due to a large wavelength fluctuation range.

[0117] In a specific embodiment, by adjusting the light source sweep frequency range in real time according to the wavelength distribution of the OTDR curve, it has been verified through experiments that the sweep frequency range can be reduced from the previous 6nm to a stable 1.6nm, the sweep step is reduced from 600 times to 160 times, and the system demodulation frequency under the same link length can be increased by 3.75 times. In other words, the link length demodulated by the system under the same demodulation frequency can also be increased by 3.75 times.

[0118] In a specific embodiment, in order to vividly represent the effect of modulating the linear frequency sweep light after the interval delay time to perform wavelength demodulation, as shown in FIG. Figure 5 As shown, Figure 5 This is a schematic diagram of the results of a wavelength demodulation embodiment provided by the present invention.

[0119] Obviously, starting to collect data after the interval delay time greatly reduces the amount of collected data, thereby effectively increasing the demodulation frequency.

[0120] In a specific embodiment, in order to vividly show the effect of adjusting the sweep frequency range, as shown in FIG. Figure 6 As shown, Figure 6 The schematic diagram of the result of adjusting the scanning frequency range according to an embodiment of the present invention is shown in the figure. As shown in the figure, the scanning range of the light source can perfectly cover the scanning range of all grating sensors, and the accuracy of the result can be guaranteed on the basis of reducing the scanning range of the light source. Since the scanning range of the light source is reduced, the demodulation frequency can be increased.

[0121] In order to solve the above problems, the present invention also provides a wavelength demodulation module for a long-distance fiber grating array, such as Figure 7 As shown, Figure 7 The structure diagram of an embodiment of a wavelength demodulation module of a long-distance fiber Bragg grating array provided by the present invention is as follows. The wavelength demodulation module 700 of the long-distance fiber Bragg grating array comprises:

[0122] A first time acquisition unit 701 is used to acquire a first time when a first grating signal sample is collected;

[0123] A delay time determining unit 702, configured to determine a delay time according to the first time;

[0124] A first wavelength range acquisition unit 703, used to acquire a first wavelength range of a first grating signal sample;

[0125] A first frequency sweep range determining unit 704, configured to determine a first frequency sweep range of the system light source according to the first wavelength range and a preset fluctuation range;

[0126] The wavelength demodulation unit 705 is used for, when wavelength demodulation is performed on a long-distance fiber grating array, after an interval delay time, the system light source collects wavelengths within the first frequency sweep range to perform wavelength demodulation.

[0127] Furthermore, in order to obtain a final demodulated signal during the wavelength demodulation process, the present invention also provides a wavelength demodulation device, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of an embodiment of a wavelength demodulation device provided by the present invention. The wavelength demodulation device 800 includes:

[0128] A linear frequency sweep light acquisition module 801 is used to acquire the linear frequency sweep light of the system light source;

[0129] The swept frequency pulse light generating module 802 is used to modulate the linear swept frequency light after the interval delay time to generate the swept frequency pulse light when the wavelength of the long-distance fiber grating array is demodulated;

[0130] A first OTDR curve acquisition module 803, used for forming a first OTDR curve of the grating by reflecting the swept frequency pulse light in the first swept frequency range through the grating array;

[0131] The electrical signal acquisition module 804 is used to perform signal conversion on the first OTDR curve to obtain an electrical signal;

[0132] The demodulation signal determination module 805 is used to perform wavelength demodulation on the electrical signal to determine a demodulation signal.

[0133] In a specific embodiment, the spectrum bandwidth of the linear frequency-sweeping light acquisition module 801 is generally 40 nm, and its output spectrum range should be larger than the maximum wavelength variation range of the grating array.

[0134] In a specific embodiment, the grating array will reflect the pulse light matching the grating center wavelength, and the pulse light of other wavelengths will be transmitted, thereby obtaining the first OTDR curve. It should be noted that the wavelength of the spectrum reflected by the grating array is linearly related to the physical parameter to be measured, and its wavelength cannot exceed the spectrum coverage range of the light source.

[0135] In a specific embodiment, by modulating the linear frequency sweep light after the interval delay time, the system can reduce the amount of data N transmitted and processed to:

[0136] N=t d ×F×B=0.95Φ0×B

[0137] Where B is the number of bytes at each sampling point; when the system processes multiple links simultaneously, the amount of data reduced will increase exponentially accordingly.

[0138] Through the above method, by performing data analysis on the first grating signal sample, determining a reasonable delay time, and modulating the linear frequency sweeping light after the interval delay time, it is achieved that when the wavelength of the long-distance fiber grating array is demodulated, the invalid grating signal acquisition process is avoided, and the demodulation frequency is correspondingly increased; by setting the first frequency sweeping range, the grating array can only reflect the frequency sweeping pulse light within the first frequency sweeping range, reducing the frequency sweeping range, thereby effectively increasing the demodulation frequency of the wavelength demodulation process.

[0139] The present invention also provides a computer-readable storage medium on which a wavelength demodulation program for a long-distance fiber grating array is stored. When the program is executed by a processor of a computer, the wavelength demodulation method for a long-distance fiber grating array as described in any of the above technical solutions is implemented.

[0140] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0141] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A wavelength demodulation method for a long-distance fiber grating array, characterized in that: include: Acquire a transmission link length of a first grating sensor, and determine a first time when the first grating sensor collects a first grating signal sample according to the transmission link length; Determine a delay time according to the first time; Acquire a first wavelength range of the first grating signal sample; Determining a first frequency sweep range of the system light source according to the first wavelength range and the preset fluctuation range; When wavelength demodulation is performed on a long-distance fiber grating array, after the delay time, the system light source collects wavelengths within the first frequency sweep range to perform wavelength demodulation; The step of determining a first frequency sweep range of a system light source according to the first wavelength range and a preset fluctuation range specifically includes: Determine a first wavelength maximum value and a first wavelength minimum value according to the first wavelength range; Determine a maximum value of a frequency sweep wavelength according to the first wavelength maximum value and the preset fluctuation range; Determining a minimum value of a frequency sweep wavelength according to the first minimum value of the wavelength and the preset fluctuation range; Determining the first frequency sweep range of the system light source according to the maximum value of the frequency sweep wavelength and the minimum value of the frequency sweep wavelength; When the wavelength of the long-distance fiber grating array is demodulated, after the delay time, the system light source collects the wavelength within the first frequency sweep range to perform wavelength demodulation, which specifically includes: Acquire linear frequency-sweep light of the system light source; When wavelength demodulation is performed on the long-distance fiber grating array, the linear frequency sweep light is modulated after the delay time to generate frequency sweep pulse light; The frequency sweep pulse light within the first frequency sweep range is reflected by the grating array to form a first OTDR curve of the grating; Performing signal conversion on the first OTDR curve to obtain an electrical signal; The electrical signal is wavelength demodulated to determine a demodulated signal.

2. The wavelength demodulation method of a long-distance fiber grating array according to claim 1, characterized in that: Determining a delay time according to the first time includes: Set the delay factor; The delay time is determined by multiplying the first time and the delay coefficient.

3. The wavelength demodulation method of a long-distance fiber grating array according to claim 1, characterized in that: Acquiring a first wavelength range of the first grating signal sample comprises: Acquire a wavelength sample of the first grating signal sample; The first wavelength range of the first grating signal sample is determined according to the wavelength sample by using a centroid peak finding algorithm.

4. The wavelength demodulation method of a long-distance fiber grating array according to claim 1, characterized in that: The frequency sweep pulse light within the first frequency sweep range is reflected by the grating array to form a first OTDR curve of the grating, and further includes: Determining a second wavelength range according to the first OTDR curve; Determining a second frequency sweep range of the system light source according to the second wavelength range and the preset fluctuation range; The swept-frequency pulse light within the second swept-frequency range is reflected by the grating array to form a second OTDR curve of the grating.

5. A wavelength demodulation module for a long-distance fiber grating array, characterized in that: include: A first time acquisition unit, used to acquire a transmission link length of a first grating sensor, and determine a first time when the first grating sensor collects a first grating signal sample according to the transmission link length; A delay time determining unit, configured to determine the delay time according to the first time; A first wavelength range acquisition unit, used to acquire a first wavelength range of the first grating signal sample; A first frequency sweep range determining unit, configured to determine a first frequency sweep range of a system light source according to the first wavelength range and a preset fluctuation range; A wavelength demodulation unit, used for, when wavelength demodulation is performed on a long-distance fiber grating array, after the delay time, the system light source collects the wavelength within the first frequency sweep range to perform wavelength demodulation; The step of determining a first frequency sweep range of a system light source according to the first wavelength range and a preset fluctuation range specifically includes: Determine a first wavelength maximum value and a first wavelength minimum value according to the first wavelength range; Determine a maximum value of a frequency sweep wavelength according to the first wavelength maximum value and the preset fluctuation range; Determining a minimum value of a frequency sweep wavelength according to the first minimum value of the wavelength and the preset fluctuation range; Determining the first frequency sweep range of the system light source according to the maximum value of the frequency sweep wavelength and the minimum value of the frequency sweep wavelength; When wavelength demodulation is performed on the long-distance fiber grating array, after the delay time, the system light source collects the wavelength within the first frequency sweep range to perform wavelength demodulation, specifically including: Acquire linear frequency-sweep light of the system light source; When wavelength demodulation is performed on the long-distance fiber grating array, the linear frequency sweep light is modulated after the delay time to generate frequency sweep pulse light; The frequency sweep pulse light within the first frequency sweep range is reflected by the grating array to form a first OTDR curve of the grating; Performing signal conversion on the first OTDR curve to obtain an electrical signal; The electrical signal is wavelength demodulated to determine a demodulated signal.

6. A wavelength demodulation device, used to execute the wavelength demodulation method of a long-distance fiber grating array according to any one of claims 1 to 4, characterized in that: include: A linear frequency-sweep light acquisition module, used to acquire the linear frequency-sweep light of the system light source; A swept frequency pulse light generating module, used for modulating the linear swept frequency light after the delay time to generate swept frequency pulse light when wavelength demodulation is performed on a long-distance fiber grating array; A first OTDR curve acquisition module, used for forming a first OTDR curve of a grating by reflecting the swept frequency pulse light within the first swept frequency range through a grating array; An electrical signal acquisition module, used for performing signal conversion on the first OTDR curve to obtain an electrical signal; The demodulation signal determination module is used to perform wavelength demodulation on the electrical signal to determine a demodulation signal.

7. A storage medium, characterized in that: The storage medium stores computer program instructions, and when the computer program instructions are executed by a computer, the computer is enabled to execute the wavelength demodulation method for a long-distance fiber grating array according to any one of claims 1 to 4.

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