Multi-parameter optical fiber sensing terminal

Abstract

The invention belongs to the technical field of optical fiber sensing, and particularly relates to a multi-parameter optical fiber sensing terminal which comprises an optical path module and a circuit module. The optical path module comprises a narrow linewidth laser, an acoustic optical modulator, an erbium-doped fiber amplifier (EDFA), a circulator, two couplers and a photoelectric detection module BPD; the circuit module comprises a power supply module, a rectification module, an FPGA / GUP board card, an A / D acquisition card and an interface board. The narrow linewidth laser is connected with one of the couplers, one of the couplers is connected with the acousto-optic modulator, the acousto-optic modulator is connected with the erbium-doped optical fiber amplifier EDFA, and the erbium-doped optical fiber amplifier EDFA is connected with the circulator; the other coupler is connected with a photoelectric detection module BPD, the photoelectric detection module BPD is connected with an A / D acquisition card, and the A / D acquisition card is connected with an FPGA / GUP board card.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber sensing, and in particular relates to a multi-parameter optical fiber sensing terminal. Background Art

[0002] In the Internet of Things network architecture, the bottom perception layer is composed of various sensors, which are mainly responsible for collecting external information. Compared with traditional electrical sensors, fiber optic sensors have irreplaceable advantages. Fiber optic sensors are small in size, resistant to electromagnetic interference, have a long lifespan, and are not easily infiltrated by water or corroded. They are low in cost, simple in wiring, and have extremely low loss, thus supporting long-distance, large-scale sensing. Light has high sensitivity to changes in the environment in which the optical fiber is located and has a large dynamic range. Therefore, fiber optic sensors have been widely used in many fields such as aerospace, biosensing, power grids, and building monitoring.

[0003] Distributed fiber optic sensors are based on the backscattering effect in optical fibers and distributed positioning technology to achieve fully distributed sensing along the optical fiber to be tested. Existing systems generally only measure a certain parameter of the optical fiber's environment. In applications where multiple aspects of the monitoring object are monitored simultaneously, multiple independent fiber optic sensing systems need to be set up. Obviously, this increases the complexity and cost of the project. In view of this, we have proposed a multi-parameter fiber optic sensing terminal. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-parameter optical fiber sensing terminal to solve the problems raised in the above-mentioned background technology in response to the above-mentioned technical problems.

[0005] In view of this, the present invention provides a multi-parameter optical fiber sensing terminal, comprising an optical path module and a circuit module;

[0006] The optical path module includes a narrow linewidth laser, an acousto-optic modulator, an erbium-doped fiber amplifier (EDFA), a circulator, two couplers, and a photoelectric detection module (BPD);

[0007] The circuit module includes a power module, a rectifier module, an FPGA / GUP board, an A / D acquisition card, and an interface board;

[0008] The narrow linewidth laser is connected to one of the couplers, one of the couplers is connected to an acousto-optic modulator, the acousto-optic modulator is connected to an erbium-doped fiber amplifier EDFA, and the erbium-doped fiber amplifier EDFA is connected to a circulator;

[0009] Another coupler is connected to a photoelectric detection module BPD, the photoelectric detection module BPD is connected to an A / D acquisition card, and the A / D acquisition card is connected to an FPGA / GUP board;

[0010] The narrow-linewidth laser, acousto-optic modulator, erbium-doped fiber amplifier (EDFA), circulator, two couplers, photoelectric detection module (BPD), rectifier module, FPGA / GPU board, A / D acquisition card, and interface board are all powered by a power module. During a single detection, two adjacent light pulses are injected into the optical fiber. The Rayleigh scattered light from the first pulse is used to measure vibration. Simultaneously, the Rayleigh scattered light from the second pulse forms the probe light and pump pulse for the temperature / strain measurement system, generating stimulated Brillouin scattering (SBS). Pulse coding is combined with pulse coding to adjust the time interval between the two pulses. The spontaneous Raman scattered light from the two pulses is then separated in the time domain for temperature measurement, resolving the issue of temperature-strain cross-sensitivity in SBS sensing.

[0011] In the above technical solution, further, the narrow linewidth laser: generates continuous laser with high coherence length and low phase noise;

[0012] Acousto-optic modulator: modulates continuous laser light into specific linear frequency modulated (LFM) light pulses. The relevant modulation parameters are determined by the AOM modulation center frequency, demodulation matching filter, and demodulation algorithm.

[0013] In the above technical solution, further, the erbium-doped fiber amplifier EDFA: amplifies the pulse light power to improve the sensing distance and the backscattered Rayleigh scattered light signal-to-noise ratio.

[0014] In the above technical solution, further, the circulator: transmits the detection light emitted by the EDFA and the Rayleigh scattered light returned by the sensing optical fiber in a specified direction.

[0015] In the above technical solution, further, the coupler: the coupler on the light source side divides the light emitted by the light source into two parts, most of the light energy enters the AOM, and a small part serves as the intrinsic light and reference light of the interference system;

[0016] The coupler on the receiving side couples the reference light and the Rayleigh backscattered light carrying the fiber acoustic wave / vibration information and interferes with each other;

[0017] Photoelectric detection module BPD: measures optical signals and can identify and measure more subtle signals.

[0018] In the above technical solution, further, the power supply module converts and processes the input power to provide voltage and current that meet the requirements of the system equipment.

[0019] In the above technical solution, further, the rectifier module: converts the AC power into DC power used by each board in the system, and can also provide charging voltage to the battery;

[0020] FPGA / GUP board: It transmits various electronic signals, and some chips are also responsible for the preliminary processing of some peripheral data.

[0021] In the above technical solution, further, the A / D acquisition card is a capture device that captures external photoelectric, video, audio and other analog signals and digitizes them into a computer for digital processing.

[0022] In the above technical solution, further, the interface board: a module that provides data forwarding function, and provides optical ports and electrical ports with different rates.

[0023] In this technical solution,

[0024] The beneficial effects of the present invention are:

[0025] 1. This multi-parameter fiber-optic sensing terminal leverages the optical fiber's inherent ability to serve as both a signal transmission medium and a sensing unit to continuously measure the distribution of physical quantities such as vibration, strain, and temperature along the fiber, thereby enabling distributed, long-distance measurement. Distributed fiber-optic sensing technologies primarily include those based on interferometry and those based on Rayleigh, Brillouin, and Raman scattering mechanisms. These technologies, used individually or in combination, enable not only high-precision and high-spatial-resolution sensing but also the simultaneous measurement of multiple physical parameters.

[0026] 2. This multi-parameter fiber-optic sensing terminal combines multiple fiber scattering mechanisms within a single fiber-optic sensing system to create a single-ended access, multi-mechanism fusion distributed fiber-optic sensing system. By integrating Rayleigh, Brillouin, and Raman scattering technologies within a single system, the system offers innovations in integration and signal processing. This overcomes the limitations of traditional distributed fiber-optic sensing systems that rely on a single scattering mechanism to measure a single variable, enabling simultaneous long-distance sensing of multiple parameters. The system can monitor strain, temperature, vibration, acoustic wave pattern, attenuation, and other conditions along the entire fiber optic line through a single fiber connected to the cable.

[0027] 3. This multi-parameter fiber-optic sensing terminal injects two adjacent light pulses into the optical fiber during a single detection. The Rayleigh scattered light from the first pulse is used to measure vibration. Simultaneously, this light pulse, combined with the second pulse, forms the probe light and pump pulse for the temperature / strain measurement system, generating stimulated Brillouin scattering (SBS). By combining pulse coding to adjust the time interval between the two pulses, the spontaneous Raman scattered light from the two pulses is separated in the time domain for temperature measurement, resolving the issue of temperature-strain cross-sensitivity in SBS sensing.

[0028] 4. This multi-parameter fiber optic sensing terminal uses the same light source and achieves simultaneous sensing of vibration, temperature, and strain by receiving only a single pulse of Rayleigh scattered light, and temperature sensing by receiving Raman scattered light. This technology achieves simultaneous measurement of multiple parameters with a streamlined system, improving measurement feedback speed. It uses a single-ended measurement method to reduce system complexity and achieve high precision, low vibration, and low noise over long distances. The distributed fiber optic sensing system with multi-mechanism fusion expands the application scenarios of distributed fiber optic sensing. Thanks to its large sensing scale and excellent sensing performance, the system cost is far lower than that of traditional sensor networks. The distributed fiber optic sensing technology with multi-mechanism fusion has broad application prospects in large-scale sensing fields such as large-scale equipment monitoring, oil and gas pipeline monitoring, rail transit monitoring, and building structure monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the system modules of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0031] In the description of this application, it should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0032] It should be noted that, in the present application, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0033] Example 1:

[0034] See also Figure 1 As shown, this embodiment provides a multi-parameter optical fiber sensing terminal.

[0035] Including optical path module and circuit module;

[0036] The optical path module includes a narrow linewidth laser, an acousto-optic modulator, an erbium-doped fiber amplifier (EDFA), a circulator, two couplers, and a photoelectric detection module (BPD).

[0037] The circuit module includes power module, rectifier module, FPGA / GUP board, A / D acquisition card, and interface board;

[0038] The narrow linewidth laser is connected to one of the couplers, one of the couplers is connected to the acousto-optic modulator, the acousto-optic modulator is connected to the erbium-doped fiber amplifier EDFA, and the erbium-doped fiber amplifier EDFA is connected to the circulator;

[0039] Another coupler on the receiving side is connected to the photoelectric detection module BPD, the photoelectric detection module BPD is connected to the A / D acquisition card, and the A / D acquisition card is connected to the FPGA / GUP board;

[0040] The narrow linewidth laser, acousto-optic modulator, erbium-doped fiber amplifier EDFA, circulator, two couplers, photoelectric detection module BPD, rectifier module, FPGA / GUP board, A / D acquisition card, and interface board are all powered by the power module.

[0041] In this approach, two adjacent light pulses are injected into the optical fiber during a single detection phase. The Rayleigh scattered light from the first pulse is used to measure vibrations. Simultaneously, the Rayleigh scattered light from the second pulse forms the probe light and pump pulse for the temperature / strain measurement system, generating stimulated Brillouin scattering. By adjusting the time interval between the two pulses using pulse coding, the spontaneous Raman scattered light from the two pulses can be distinguished in the time domain for temperature measurement, resolving the issue of temperature-strain cross-sensitivity in stimulated Brillouin scattering sensing.

[0042] In this embodiment, the narrow linewidth laser: generates continuous laser light with high coherence length and low phase noise;

[0043] Acousto-optic modulator: modulates continuous laser light into specific linear frequency modulated (LFM) light pulses. The relevant modulation parameters are determined by the AOM modulation center frequency, demodulation matching filter, and demodulation algorithm.

[0044] Among them, the narrow linewidth laser emits narrow linewidth laser, which can improve the resolution of optical fiber sensing events. The coupler on the light source side divides the light emitted by the light source into two parts, and most of the light energy enters the acousto-optic modulator as signal light.

[0045] In this embodiment, the erbium-doped fiber amplifier (EDFA) amplifies the pulse light power, thereby increasing the sensing distance and the signal-to-noise ratio of the backscattered Rayleigh light.

[0046] Rayleigh scattering, also known as molecular scattering, is a light scattering phenomenon. When particles are much smaller than the wavelength of the incident light (typically less than one-tenth of the wavelength), they scatter light in all directions with varying intensities, with the intensity of the scattered light being inversely proportional to the fourth power of the wavelength of the incident light. This phenomenon is known as Rayleigh scattering.

[0047] In this embodiment, the circulator transmits the detection light emitted by the EDFA and the Rayleigh scattered light returned by the sensing optical fiber in a specified direction.

[0048] The detection light emitted by the erbium-doped fiber amplifier EDFA and the scattered light returned by the sensing fiber are transmitted in a specified direction through a circulator.

[0049] In this embodiment, the coupler: The coupler on the light source side splits the light emitted by the light source into two parts, most of the light energy enters the AOM, and a small part serves as the intrinsic light and reference light of the interference system;

[0050] The coupler on the receiving side couples the reference light and the Rayleigh backscattered light carrying the fiber acoustic wave / vibration information and interferes with each other;

[0051] Photoelectric detection module BPD: measures optical signals and can identify and measure more subtle signals.

[0052] Among them, couplers are common components in electronic, communication, optical and mechanical systems, used to transfer energy (signal or power) between two or more circuits, optical paths or mechanical components, while realizing specific functions such as signal distribution, isolation, mixing or mode conversion.

[0053] In this embodiment, the power module converts and processes the input power to provide voltage and current that meet the requirements of the system equipment.

[0054] Among them, the power supply module is set to provide power for the narrow linewidth laser, acousto-optic modulator, erbium-doped fiber amplifier EDFA, circulator, two couplers, photoelectric detection module BPD, rectifier module, FPGA / GUP board, A / D acquisition card, and interface board to process the voltage and current.

[0055] In this embodiment, the rectifier module: converts AC power into DC power used by the various boards in the system, and can also provide charging voltage for the battery;

[0056] FPGA / GUP board: It transmits various electronic signals, and some chips are also responsible for the preliminary processing of some peripheral data.

[0057] FPGA is a semiconductor device that can be programmed to configure hardware logic. FPGA board is a circuit board that integrates FPGA chip with other components (such as memory, interface, etc.);

[0058] GPU (Graphics Processing Unit) was originally designed for graphics rendering and is now widely used in parallel computing. GPU boards usually refer to independent accelerator cards that contain GPU chips (such as NVIDIA's Tesla series).

[0059] In this embodiment, the A / D acquisition card is a capture device that captures external photoelectric, video, audio and other analog signals and digitizes them into a computer for digital processing.

[0060] Among them, A / D acquisition card is a hardware device that converts analog signals into digital signals. It is usually integrated into the computer system in the form of a plug-in card (such as PCI, PCI e, USB and other interfaces). It is the core component of the data acquisition system and is widely used in industrial control, scientific experiments, medical equipment, audio processing and other fields.

[0061] In this embodiment, the interface board is a module that provides data forwarding function and provides optical ports and electrical ports with different rates.

[0062] Among them, the interface board is an electronic hardware component that is mainly used to provide connection and signal conversion functions between different systems, devices or components.

[0063] During use: a narrow-linewidth laser is emitted by a narrow-linewidth laser, which can improve the resolution of fiber-optic sensing events. The coupler on the light source side splits the light emitted by the light source into two parts. Most of the light energy enters the acousto-optic modulator as signal light, and a small part serves as the intrinsic light and reference light of the interference system. The acousto-optic modulator combines the modulated signal into the signal light, and the signal light is amplified by the erbium-doped fiber amplifier (EDFA). The signal light will have backscattered light in the optical fiber. The detection light emitted by the erbium-doped fiber amplifier (EDFA) and the scattered light returned by the sensing optical fiber are transmitted in the specified direction through the circulator.

[0064] The coupler on the receiving side couples the reference light and the Rayleigh backscattered light carrying the fiber's acoustic / vibration information, creating interference. The coupled optical signal is detected by the photoelectric detection module (BPD) and transmitted to the A / D acquisition card for analog-to-digital conversion. The data is then demodulated by the FPGA / GPU board and transmitted to the server for in-depth processing and display.

[0065] The embodiments of the present application are described above in conjunction with the accompanying drawings. Unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A multi-parameter fiber optic sensing terminal, comprising an optical path module and a circuit module, characterized in that: The optical path module includes a narrow linewidth laser, an acousto-optic modulator, an erbium-doped fiber amplifier (EDFA), a circulator, two couplers, and a photoelectric detection module (BPD); The circuit module includes a power module, a rectifier module, an FPGA / GUP board, an A / D acquisition card, and an interface board; The narrow linewidth laser is connected to one of the couplers, one of the couplers is connected to an acousto-optic modulator, the acousto-optic modulator is connected to an erbium-doped fiber amplifier EDFA, and the erbium-doped fiber amplifier EDFA is connected to a circulator; Another coupler is connected to a photoelectric detection module BPD, the photoelectric detection module BPD is connected to an A / D acquisition card, and the A / D acquisition card is connected to an FPGA / GUP board; The narrow linewidth laser, acousto-optic modulator, erbium-doped fiber amplifier EDFA, circulator, two couplers, photoelectric detection module BPD, rectifier module, FPGA / GUP board, A / D acquisition card and interface board are all powered by a power module.

2. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The narrow linewidth laser generates continuous laser light with high coherence length and low phase noise; Acousto-optic modulator: modulates continuous laser light into specific linear frequency modulated (LFM) light pulses. The relevant modulation parameters are determined by the AOM modulation center frequency, demodulation matching filter, and demodulation algorithm.

3. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The erbium-doped fiber amplifier EDFA amplifies the pulse light power, thereby improving the sensing distance and the backscattered Rayleigh light signal-to-noise ratio.

4. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The circulator transmits the detection light emitted by the EDFA and the Rayleigh scattered light returned by the sensing optical fiber in a specified direction.

5. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The coupler: The coupler on the light source side splits the light emitted by the light source into two parts, most of the light energy enters the AOM, and a small part is used as the intrinsic light and reference light of the interference system; The coupler on the receiving side couples the reference light and the Rayleigh backscattered light carrying the fiber acoustic wave / vibration information and interferes with each other; Photoelectric detection module BPD: measures optical signals and can identify and measure more subtle signals.

6. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The power module converts and processes the input power to provide voltage and current that meet the requirements of the system equipment.

7. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The rectifier module converts AC power into DC power used by the boards in the system and provides charging voltage to the battery. FPGA / GUP board: It transmits various electronic signals, and some chips are also responsible for the preliminary processing of some peripheral data.

8. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The A / D acquisition card is a capture device that captures external photoelectric, video, audio and other analog signals and digitizes them into a computer for digital processing.

9. The multi-parameter optical fiber sensing terminal according to claim 1, characterized in that: The interface board is a module that provides data forwarding function and provides optical ports and electrical ports with different speeds.

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