High-capacity wavelength division multiplexing fiber Bragg grating sensing system

Abstract

The utility model relates to a high-capacity wavelength division multiplexing fiber bragg grating sensing system in the field of fiber sensing. The high-capacity wavelength division multiplexing fiber bragg grating sensing system comprises a mode-locked fiber laser, a spectrum expansion module, a three-port optical circulator, a fiber bragg grating array, a dispersion module, a photoelectric detector, a data acquisition module and a data processing module. The spectrum expansion module is composed of an optical fiber amplifier, a nonlinear element and a polarization controller; the optical fiber amplifier is composed of an optical isolator, an erbium-doped optical fiber, a wavelength division multiplexer and a pump light source. According to the sensing system, the dispersion Fourier transform technology is applied, the offset of the center wavelength of the fiber bragg grating is mapped into the offset of time delay between time domain reflected light pulses, and the demodulation rate and precision of the fiber bragg grating sensing system are improved; and by adding a spectrum expansion module, the spectrum of pulse data output by the light source laser is expanded into a super-continuum spectrum by using a nonlinear effect, and the simultaneous measurement of hundreds of fiber bragg grating sensors can be theoretically supported.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical fiber sensing, and in particular relates to a large-capacity wavelength division multiplexing optical fiber Bragg grating sensing system. Background Art

[0002] Fiber Bragg grating is an optical waveguide device, which is made by periodically changing the refractive index of the optical fiber core under the irradiation of ultraviolet light. When the external environmental parameters (temperature or stress) of the fiber Bragg grating change, its central wavelength will change accordingly. By demodulating the drift of the central wavelength of the fiber Bragg grating, the measurement of external physical quantities can be achieved. Therefore, fiber Bragg grating has been widely used in the field of sensors. Fiber Bragg grating sensors have the advantages of anti-electromagnetic interference, compact structure, fast response, long life, easy multiplexing, etc., and can measure a variety of physical parameters such as strain, temperature, pressure, liquid level, concentration, refractive index, etc., and play an important role in state monitoring in the fields of ocean, aerospace, transportation, chemical industry, petroleum, medicine, etc.

[0003] The advantage of fiber Bragg sensors being easy to multiplex is that they provide an excellent technical option for simultaneous monitoring of multiple points as quasi-distributed sensors. Wavelength division multiplexing is a common multiplexing method for fiber Bragg grating sensors. Wavelength division multiplexing technology connects multiple sensors with different working wavelengths to one optical fiber. Because the working ranges of different sensors do not overlap, there is almost no crosstalk between them, so independent sensing of physical quantities can be achieved in different sensors.

[0004] Fiber Bragg grating sensing systems rely on fiber Bragg grating wavelength demodulation technology. However, traditional fiber Bragg grating sensing systems are limited by the scanning rate of optical instruments such as spectrometers and cannot achieve a high demodulation rate. As the amount of real-time data increases, once the sensing system delays fault detection due to the lag in demodulation rate, a large amount of data may be lost.

[0005] Dispersive Fourier transform technology provides a new high-speed transient measurement method. By analyzing the time domain information of the optical pulse, the spectral information of the optical pulse can be inverted. When this technology is used in the fiber Bragg grating sensing system, each pulse reflected back by the fiber Bragg grating can be demodulated. At this time, the demodulation rate is the repetition frequency of the laser as the light source, which can achieve fast, accurate and real-time measurement of the spectrum.

[0006] CN105444793A discloses a fiber Bragg grating sensing device based on a high-speed pulse laser, which uses dispersive Fourier transform technology, takes a high-speed pulse laser as a light source, uses a section of dispersive medium to time-stretch the fiber Bragg grating reflected light pulse, and maps the spectral information of the fiber Bragg grating contained in the reflected light pulse from the spectral domain to the time domain, thereby achieving high-speed and high-precision sensing.

[0007] However, in the wavelength division multiplexing fiber Bragg grating array high-speed sensing system, since each sensor occupies a part of the independent wavelength range, the sensor capacity of the system is directly limited by the spectral width of the light source laser, and the capacity is difficult to exceed 30. This problem of insufficient capacity makes it gradually difficult to meet the application requirements of real-time quasi-distributed sensing that requires a large number of sensors, which greatly restricts its development in transformer monitoring, shape sensing, medicine and other fields. Therefore, the existing fiber Bragg grating sensing system needs further improvement. Utility Model Content

[0008] In view of the above situation, in order to solve the problems existing in the existing fiber Bragg grating sensing system, the utility model provides a large-capacity wavelength division multiplexing fiber Bragg grating sensing system. After the spectrum expansion module, the laser spectrum can be broadened to several times the original spectrum, and theoretically can support the simultaneous measurement of hundreds of fiber Bragg grating sensors.

[0009] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0010] A large-capacity wavelength division multiplexing fiber Bragg grating sensing system comprises a mode-locked fiber laser, a spectrum expansion module, a three-port optical circulator, a fiber Bragg grating array, a dispersion module, a photoelectric detector, a data acquisition module and a data processing module.

[0011] The output end of the mode-locked fiber laser is connected to the input end of the spectrum expansion module; the output end of the spectrum expansion module is connected to the first port of the three-port optical circulator; the second port of the three-port optical circulator is connected to the fiber Bragg grating array; the third port of the three-port optical circulator is connected to the input end of the dispersion module; the output end of the dispersion module is connected to the photodetector, the data acquisition module and the data processing module in sequence.

[0012] Furthermore, the spectrum expansion module is composed of an optical fiber amplifier, a nonlinear element and a polarization controller connected in series in sequence; the connection between the elements in the spectrum expansion module is realized by using a single-mode optical fiber.

[0013] The optical fiber amplifier in the spectrum expansion module can be single-stage or multi-stage, and the gain medium of the amplifier can be an optical element that can be used as the gain medium of the optical fiber amplifier, such as erbium-doped fiber, ytterbium-doped fiber or thulium-doped fiber.

[0014] The spectrum extension module introduces a large amount of nonlinearity into the optical signal, so that the spectrum of the optical pulse is broadened into a supercontinuum spectrum under the combined action of multiple nonlinear effects, so that the output spectrum width is sufficient to cover the reflection spectrum range of a large-capacity fiber Bragg grating array.

[0015] The nonlinear element in the spectrum expansion module can be one of the optical devices that are helpful for generating supercontinuum, such as high nonlinear optical fiber, ordinary single-mode dispersion-shifted optical fiber, dispersion-decreasing optical fiber, dispersion-flattened optical fiber, dispersion-flattened-decreasing optical fiber, photonic crystal optical fiber and nonlinear photonic chip. The nonlinear element is preferably a high nonlinear optical fiber.

[0016] The polarization controller is used to adjust the polarization state of the output signal and the spectral shape of the output signal, thereby obtaining a smoother output pulse spectrum and balancing the intensity between pulses in the reflected pulse sequence of the fiber Bragg grating array.

[0017] The polarization controller in the spectrum expansion module can be a mechanical polarization controller, an electro-optic polarization controller, a thermo-optic polarization controller, an acousto-optic polarization controller, a liquid crystal polarization controller or an integrated optical waveguide polarization controller.

[0018] When the input optical signal strength of the spectrum expansion module is high enough, the optical fiber amplifier part can be omitted in the module; and the positions of the components in the module can be interchanged on the premise that the optical fiber amplifier is before the nonlinear component.

[0019] Furthermore, the optical fiber amplifier is composed of an optical isolator, an erbium-doped optical fiber, a wavelength division multiplexer, and a pump light source; the optical isolator, erbium-doped optical fiber, wavelength division multiplexer, high nonlinear optical fiber, and polarization controller are connected in series in sequence with single-mode optical fiber.

[0020] The pump light source of the optical fiber amplifier can be coupled into the optical fiber amplifier through a wavelength division multiplexer by forward coupling, backward coupling or bidirectional coupling. When the coupling method of the pump light source adopts backward coupling or bidirectional coupling, an optical isolator is added to the input end of the amplifier to prevent the reverse propagation of light.

[0021] The optical isolator takes the direction from the input end of the spectrum expansion module to the input end of the erbium-doped optical fiber as the forward direction. Preferably, the pump light source is reversely coupled in the transmission optical path.

[0022] Furthermore, the mode-locked fiber laser uses active mode locking or passive mode locking to generate ultrashort pulses with high repetition frequency, wide spectrum and narrow pulse width as the light source of the sensing system; the time interval of the light pulse output by the mode-locked fiber laser is greater than the total time length of the light pulse sequence reflected by the fiber Bragg grating array.

[0023] Furthermore, the three-port optical circulator is used to guide the optical signal to the fiber Bragg grating array and the dispersion module in a corresponding manner according to the port sequence.

[0024] Furthermore, the fiber Bragg grating array is composed of a plurality of fiber Bragg grating sensors connected in series, the plurality of fiber Bragg gratings have different central wavelengths to realize wavelength division multiplexing of the sensor, and each fiber Bragg grating sensor is used to monitor the corresponding external physical condition.

[0025] Furthermore, the dispersion module is used to provide a sufficiently large dispersion value for the reflected light pulse sequence from the fiber Bragg grating array. Under the action of the dispersion Fourier transform principle, the reflected light pulses produce different delays for optical signals of different wavelengths, thereby mapping the spectral information of the fiber Bragg grating carried by the reflected light pulses to the inter-pulse delay in the time domain.

[0026] Furthermore, the photoelectric detector is used to convert the reflected light pulse signal after wavelength-time mapping into an electrical signal.

[0027] Furthermore, the data acquisition module is a data acquisition card or a high-speed oscilloscope, which is used to collect electrical signals from the photoelectric detector and convert them into digital signals.

[0028] Furthermore, the data processing module is a digital signal processor or computer software, which is used to analyze the signal obtained by the data acquisition module in the time domain, demodulate the wavelength information of the reflected light pulse in the spectral domain from the time delay between the reflected light pulses in the time domain, and further calculate the external physical conditions measured by the fiber Bragg grating sensor corresponding to each reflected light pulse.

[0029] The present invention also includes other components that enable it to be used normally, all of which are conventional means in the field. In addition, devices or components not limited in the present invention, such as: mode-locked fiber laser, three-port optical circulator, optical isolator, erbium-doped fiber, wavelength division multiplexer, pump light source, high nonlinear fiber, polarization controller, fiber Bragg grating, dispersion module, photodetector, data acquisition module and data processing module, etc., all adopt the existing technology in the field.

[0030] The beneficial effects of the utility model are as follows:

[0031] First of all, this large-capacity wavelength-division multiplexed fiber Bragg grating sensing system realizes multi-point real-time measurement of physical quantities by installing fiber Bragg grating sensors at monitoring points, adopts a high-repetition-rate mode-locked fiber laser as the light source, and uses the dispersion Fourier transform technology to map the offset of the fiber Bragg grating central wavelength to the offset of the time delay between time-domain reflected light pulses. The demodulation rate of the system is equivalent to the repetition frequency of the light source laser used, which greatly improves the demodulation rate and demodulation accuracy of the fiber Bragg grating sensing system, thereby realizing a high-speed, high-precision fiber Bragg grating array sensing system.

[0032] In addition, by adding a spectrum expansion module, the sensing system utilizes the nonlinear effect to broaden the spectrum of the pulse data output by the light source laser into a supercontinuum spectrum, thereby overcoming the direct limitation of the light source laser bandwidth on the sensor capacity in the fiber Bragg grating array high-speed sensing system, and significantly improving the number of multiplexed fiber Bragg grating sensors in the current fiber Bragg grating high-speed sensing system. The laser spectrum after the spectrum expansion module can be broadened to several times the original spectrum, and theoretically can support the simultaneous measurement of hundreds of fiber Bragg grating sensors, which can meet the application requirements of simultaneous measurement of larger-scale monitoring points.

[0033] Furthermore, the sensing system adopts an all-optical fiber structure, which has the characteristics of anti-electromagnetic interference, compact structure, strong stability, easy and flexible installation, etc. It has broad application prospects in harsh environments such as strong magnetic fields, extreme temperatures, flammable and explosive environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are provided to provide further understanding of the present application. They are included in and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the description serve to explain the principle of the present invention.

[0035] In the attached figure:

[0036] Figure 1 It is a schematic diagram of the structure of the fiber Bragg grating sensing system in the utility model.

[0037] Figure 2 It is a structural schematic diagram of the spectrum expansion module in the utility model.

[0038] In the figure: 1-1, mode-locked fiber laser; 1-2, spectrum expansion module; 1-3, three-port optical circulator; 1-4, fiber Bragg grating array; 1-5, dispersion module; 1-6, photodetector; 1-7, data acquisition module; 1-8, data processing module; 2-1, optical isolator; 2-2, erbium-doped fiber; 2-3, wavelength division multiplexer; 2-4, pump light source; 2-5, highly nonlinear fiber; 2-6, polarization controller. DETAILED DESCRIPTION

[0039] The technical solution of the present utility model will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments.

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0041] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0042] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0043] Example

[0044] like Figure 1As shown, a large-capacity wavelength division multiplexing fiber Bragg grating sensing system includes a mode-locked fiber laser 1-1, a spectrum expansion module 1-2, a three-port optical circulator 1-3, a fiber Bragg grating array 1-4, a dispersion module 1-5, a photodetector 1-6, a data acquisition module 1-7, and a data processing module 1-8. The connection relationship of the above-mentioned components is as follows: the output end of the mode-locked fiber laser 1-1 is connected to the input end of the spectrum expansion module 1-2; the output end of the spectrum expansion module 1-2 is connected to the first port of the three-port optical circulator 1-3; the second port of the three-port optical circulator 1-3 is connected to the fiber Bragg grating array 1-4; the third port of the three-port optical circulator 1-3 is connected to the input end of the dispersion module 1-5; the output end of the dispersion module 1-5 is connected to the photodetector 1-6, the data acquisition module 1-7, and the data processing module 1-8 in sequence.

[0045] The mode-locked fiber laser 1-1 uses active mode locking or passive mode locking to generate ultrashort pulses with high repetition frequency, wide spectrum and narrow pulse width as the light source of the sensing system; the time interval of the light pulse output by the mode-locked fiber laser 1-1 is greater than the total time length of the light pulse sequence reflected by the fiber Bragg grating array 1-4.

[0046] like Figure 2 As shown, the spectrum expansion module 1-2 is composed of an optical fiber amplifier, a nonlinear element and a polarization controller 2-6 connected in series in sequence; wherein the optical fiber amplifier is composed of an optical isolator 2-1, an erbium-doped optical fiber 2-2, a wavelength division multiplexer 2-3, and a pump light source 2-4; and the nonlinear element is a highly nonlinear optical fiber 2-5. The optical isolator 2-1, the erbium-doped optical fiber 2-2, the wavelength division multiplexer 2-3, the highly nonlinear optical fiber 2-5, and the polarization controller 2-6 are sequentially connected in series with a single-mode optical fiber; the optical isolator 2-1 takes the input end of the spectrum expansion module 1-2 to the input end of the erbium-doped optical fiber 2-2 as the forward direction, and the pump light source 2-4 is reversely coupled in the transmission optical path.

[0047] The three-port optical circulator 1-3 is used to receive the optical signal transmitted by the spectrum expansion module 1-2 and the optical signal reflected by the fiber Bragg grating array 1-4, and guide the received optical signal to the fiber Bragg grating array 1-4 and the dispersion module 1-5 according to the port sequence. The three-port optical circulator 1-3 can be a device capable of realizing directional optical coupling, such as an optical splitter and an optical coupler.

[0048] The fiber Bragg grating arrays 1-4 are composed of a plurality of fiber Bragg grating sensors connected in series, wherein the plurality of fiber Bragg gratings have different central wavelengths, and each fiber Bragg grating sensor is used to monitor the external physical conditions corresponding to the sensor.

[0049] The dispersion modules 1-5 are used to provide a sufficiently large dispersion value for the reflected light pulse sequence from the fiber Bragg grating array. Under the action of the dispersion Fourier transform principle, the reflected light pulses produce different delays for optical signals of different wavelengths, thereby mapping the spectral information of the fiber Bragg grating carried by the reflected light pulses to the inter-pulse delay in the time domain. The dispersion modules 1-5 can use dispersion-compensating optical fibers, chirped fiber Bragg gratings or single-mode optical fibers, etc., which can provide linear group velocity dispersion.

[0050] The photoelectric detectors 1-6 are used to convert the reflected light pulse signals after wavelength-time mapping into electrical signals.

[0051] The data acquisition module 1-7 is a data acquisition card or a high-speed oscilloscope, which is used to collect the electrical signals from the photodetector 1-6 and convert them into digital signals.

[0052] The photoelectric detector 1-6 is connected to the data acquisition module 1-7 by a standard radio frequency line, the data acquisition module 1-7 is connected to the data processing module 1-8 by GPIB, serial communication or local area network, and the connection between the remaining modules in the system is realized by single-mode optical fiber.

[0053] The data processing module 1-8 is a digital signal processor or computer software, which is used to analyze the signal obtained by the data acquisition module 1-7 in the time domain, demodulate the wavelength information of the reflected light pulse in the spectral domain from the time delay between the reflected light pulses in the time domain, and further calculate the external physical conditions measured by the fiber Bragg grating sensor corresponding to each reflected light pulse.

[0054] The working principle of the utility model is as follows:

[0055] The optical pulse emitted by the mode-locked fiber laser 1-1 reaches the spectrum extension module 1-2. In the spectrum extension module 1-2, the pump light source 2-4 generates pump light and couples it into the erbium-doped optical fiber 2-2 in the opposite direction to the optical pulse data through the wavelength division multiplexer 2-3. The optical isolator 2-1 prevents the pump light from transmitting in the reverse direction in the system. The optical pulse data is amplified in the erbium-doped optical fiber 2-2. The amplified optical pulse data enters the high nonlinear optical fiber 2-5, accumulates a large amount of nonlinearity, and the spectrum of the optical pulse data is broadened to a supercontinuum spectrum. The adjustment of the polarization controller 2-6 makes the broadened optical pulse data smoother. Finally, the spectrum of the optical pulse data output by the spectrum extension module 1-2 is expanded, and its spectrum width is sufficient to cover the reflection spectrum range of the large-capacity fiber Bragg grating array 1-4.

[0056] After data amplification and spectrum expansion, the optical pulse passes through the first port and the second port of the three-port optical circulator 1-3 in turn and enters the fiber Bragg grating array 1-4; according to the working principle of the fiber Bragg grating, the fiber Bragg grating array 1-4 will reflect a series of reflected light pulse sequences with different central wavelengths; the reflected light pulse sequence passes through the second port of the three-port optical circulator 1-3 again, and is output from the third port to enter the dispersion module 1-5.

[0057] When the external physical conditions of a fiber Bragg grating in the fiber Bragg grating array 1-4 change, its central wavelength will drift accordingly. According to the dispersion Fourier transform principle, the dispersion module 1-5 will cause different time delays of reflected light pulses with different central wavelengths, thereby mapping the difference in the central wavelength of the fiber Bragg grating in the spectral domain to the difference in the time delay between reflected light pulses in the time domain. The mapping relationship between wavelength and time can be expressed as:

[0058] Δτ=D·Δλ

[0059] Among them, Δτ is the change in the time delay between the two pulses before and after passing through the dispersion module 1-5, Δλ is the distance of the center wavelength between the two pulses, and D is the total dispersion value of the dispersion element. The reflected light pulse sequence stretched by the dispersion module 1-5 is converted into electrical data by the photodetector 1-6, and then collected and quantized by the data acquisition module 1-7, and then converted into digital data and sent to the data processing module 1-8.

[0060] The first fiber Bragg grating in the fiber Bragg grating sequence is used as a reference grating, and its external physical conditions are kept unchanged; the data processing module 1-8 can select a reflected light pulse of a corresponding reference grating in a group of reflected light pulse sequences as a reference pulse, and calculate the time delay between the reference pulse and the remaining light pulses in the same group of reflected light pulse sequences; when the central wavelength of a fiber Bragg grating other than the reference grating drifts, the time delay between the reflected light pulses corresponding to the fiber Bragg grating and the reference grating will change accordingly, and the data processing module 1-8 can detect the delay change and calculate the central wavelength drift of the corresponding fiber Bragg grating, thereby obtaining the external physical conditions of the fiber Bragg grating monitoring point.

[0061] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Without departing from the scope and spirit of the described embodiments, many modifications and changes are obvious to ordinary technicians in this technical field. Any technical deformation made within the spirit and principles of the present invention falls within the protection scope of the present invention.

Claims

1. A high-capacity wavelength division multiplexing fiber Bragg grating sensing system, characterized in that: It includes a mode-locked fiber laser (1-1), a spectrum expansion module (1-2), a three-port optical circulator (1-3), a fiber Bragg grating array (1-4), a dispersion module (1-5), a photodetector (1-6), a data acquisition module (1-7) and a data processing module (1-8); The output end of the mode-locked fiber laser (1-1) is connected to the input end of the spectrum expansion module (1-2); the output end of the spectrum expansion module (1-2) is connected to the first port of the three-port optical circulator (1-3); the second port of the three-port optical circulator (1-3) is connected to the fiber Bragg grating array (1-4); the third port of the three-port optical circulator (1-3) is connected to the input end of the dispersion module (1-5); and the output end of the dispersion module (1-5) is sequentially connected to a photodetector (1-6), a data acquisition module (1-7) and a data processing module (1-8).

2. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 1 is characterized in that: The spectrum expansion module (1-2) is composed of an optical fiber amplifier, a nonlinear element and a polarization controller (2-6) connected in series.

3. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 2 is characterized in that: The optical fiber amplifier is composed of an optical isolator (2-1), an erbium-doped optical fiber (2-2), a wavelength division multiplexer (2-3), and a pump light source (2-4); the nonlinear element is a high nonlinear optical fiber (2-5); the optical isolator (2-1), the erbium-doped optical fiber (2-2), the wavelength division multiplexer (2-3), the high nonlinear optical fiber (2-5), and the polarization controller (2-6) are sequentially connected in series with a single-mode optical fiber; the pump light source (2-4) is reversely coupled in the transmission optical path; the optical isolator (2-1) takes the input end of the spectrum expansion module (1-2) to the input end of the erbium-doped optical fiber (2-2) as the forward direction.

4. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 1 is characterized in that: The mode-locked fiber laser (1-1) uses active mode locking or passive mode locking to generate ultrashort pulses with high repetition frequency, wide spectrum and narrow pulse width, which are used as the light source of the sensing system.

5. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 1 is characterized in that: The three-port optical circulator (1-3) is used to guide the optical signal to each module in the sensor system in accordance with the order of the ports.

6. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 1, characterized in that: The fiber Bragg grating array (1-4) is composed of a plurality of fiber Bragg grating sensors, and each fiber Bragg grating sensor is used to monitor the external physical conditions corresponding to the sensor.

7. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 1, characterized in that: The dispersion module (1-5) is used to provide a dispersion value for a reflected light pulse sequence from a fiber Bragg grating array (1-4). Under the action of the dispersion Fourier transform principle, optical signals of different wavelengths of the reflected light pulses produce different time delays.

8. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 7, characterized in that: The photoelectric detector (1-6) is used to convert the reflected light pulse signal after wavelength-time mapping into an electrical signal.

9. The high-capacity wavelength division multiplexing fiber Bragg grating sensing system according to claim 8, characterized in that: The data acquisition module (1-7) is a data acquisition card or a high-speed oscilloscope, which is used to collect electrical signals from the photoelectric detector (1-6) and convert them into digital signals.

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