Multi-component gas concentration detection system based on hollow-core anti-resonance optical fiber

Abstract

The invention discloses a multi-component gas concentration detection system based on a hollow-core anti-resonance optical fiber. The system comprises a signal generation module, a laser emission module, an optical fiber coupling module, an input optical fiber, a gas chamber module, a gas exchange acceleration module, an output optical fiber, a photoelectric conversion module, a signal demodulation module and a data processing module. The laser transmitting module comprises at least two paths of tunable lasers which are respectively used for receiving the composite modulation signals and outputting narrow-linewidth scanning light beams with wavelengths corresponding to different gas characteristic absorption peaks; the optical fiber coupling module is used for combining the light beams output by the at least two paths of tunable lasers into one beam of composite light; the photoelectric conversion module is used for receiving the emergent light absorbed by the gas and converting the emergent light into an electric signal; the signal demodulation module is used for carrying out harmonic demodulation on the electric signal by taking the composite modulation signal as a reference and extracting an absorption characteristic signal corresponding to each gas; and the data processing module is used for calculating the concentration value corresponding to each gas according to the absorption characteristic signal.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and in particular to a multi-component gas concentration detection system based on hollow anti-resonant optical fiber. Background Technology

[0002] Lithium-ion and sodium-ion batteries, among other alkali metal-ion batteries, are widely used in electric vehicles and large-scale energy storage systems. However, under abnormal conditions such as overcharging, internal short circuits, or thermal runaway, various flammable and toxic gases, such as carbon monoxide (CO) and hydrogen, can be released inside the battery. ), methane ( ) and acetylene ( Real-time, in-situ monitoring of the composition and concentration of these gases is crucial for early warning of battery thermal runaway and ensuring system safety. Similarly, in industries such as petrochemicals, hydrogen sulfide (…) is present during production, storage, and transportation. ), carbon monoxide (CO), methane ( Leakage monitoring of hazardous gases such as [specific gases] is also a core requirement for industrial safety. Therefore, developing a technological platform capable of simultaneously, rapidly, and with high sensitivity detecting multi-component gases is of great significance for the construction of cross-industry safety protection systems.

[0003] Gas detection technology based on optical absorption principles has become a research hotspot due to its advantages such as high selectivity and non-contact measurement. Key gas molecules exhibit characteristic absorption lines in the ultraviolet and near-infrared bands, providing a physical basis for specific identification. However, existing optical gas sensing technologies still face significant challenges in achieving high sensitivity, rapid response, and system integration, mainly reflected in the following three typical approaches:

[0004] Firstly, traditional high-sensitivity solutions based on multi-pass cells improve sensitivity by increasing the optical path length. However, their optical path structure is complex and relies on spatial optical components (such as lenses and mirrors), resulting in a large system size, poor structural stability, and difficulty in deploying them in space-constrained scenarios such as inside battery packs or industrial sites.

[0005] Secondly, the integrated scheme based on quartz-enhanced photoacoustic spectroscopy: although it achieves miniaturization to a certain extent, it introduces an acoustic resonance unit and its precision control system, which increases the complexity and cost of the system. Environmental vibration and other interference factors also pose challenges to its stability.

[0006] Thirdly, there is the scheme based on the combination of hollow-core optical fiber and tunable semiconductor laser absorption spectroscopy: This scheme utilizes hollow-core optical fiber as a gas chamber and optical waveguide, effectively extending the interaction length between light and gas and improving system integration. However, it still has inherent drawbacks: First, due to the slow gas diffusion process within the micron-sized hollow core of the optical fiber, the sensor response time is as long as several minutes or even hours, which cannot meet the urgent need for real-time monitoring; second, most existing research focuses on the detection of single gases and lacks the ability to simultaneously and in-situ analyze complex gas mixtures (such as multiple gases released during battery thermal runaway); third, it is difficult to simultaneously achieve the desired results in key performance indicators such as detection sensitivity, dynamic range (covering ppm to tens of thousands of ppm), and system noise.

[0007] In summary, existing technologies struggle to achieve a good balance between core performance characteristics such as high response speed, multi-component simultaneous detection capability, high system integration, and high sensitivity over a wide dynamic range. Therefore, developing a novel sensor system that can fundamentally accelerate gas exchange, support multi-band laser synchronization, and maintain the stability of an all-fiber structure is crucial to overcoming current technological bottlenecks. Summary of the Invention

[0008] To address the aforementioned issues, this invention provides a multi-component gas concentration detection system based on hollow anti-resonant optical fiber. By integrating the gas path with an all-fiber optical structure, it enables high-speed, in-situ, and synchronous detection of various characteristic gases.

[0009] In a first aspect, embodiments of the present invention provide a multi-component gas concentration detection system based on hollow anti-resonant optical fiber, the system comprising: a signal generation module, a laser emission module, an optical fiber coupling module, an input optical fiber, a gas chamber module, a gas exchange acceleration module, an output optical fiber, a photoelectric conversion module, a signal demodulation module, and a data processing module;

[0010] The signal generation module is used to generate independent composite modulation signals;

[0011] The laser emitting module includes at least two tunable lasers, which respectively receive composite modulation signals and output narrow linewidth scanning beams with wavelengths corresponding to the characteristic absorption peaks of different gases.

[0012] Fiber optic coupling module, used to combine the beams output from at least two tunable lasers into a single composite beam;

[0013] The gas chamber module includes a hollow anti-resonant optical fiber. The two ends of the hollow anti-resonant optical fiber are connected to the input optical fiber and the output optical fiber respectively through optical fiber connection structures. The hollow core inside the hollow anti-resonant optical fiber forms a gas absorption cavity, which is used to contain the gas to be measured and interact with the composite light through absorption.

[0014] The gas exchange acceleration module is located in the gas path of the gas absorption chamber and is used to regulate the gas pressure in the gas path to accelerate the replacement of gas in the gas absorption chamber.

[0015] A photoelectric conversion module is used to receive the emitted light after it has been absorbed by the gas and convert it into an electrical signal.

[0016] The signal demodulation module is used to perform harmonic demodulation on the electrical signal with reference to the composite modulation signal and extract the absorption characteristic signals corresponding to each gas.

[0017] The data processing module is used to calculate the concentration value of each gas based on the absorption characteristic signal.

[0018] In some possible embodiments, the hollow anti-resonant fiber is a hollow anti-resonant fiber operating in the ultraviolet and / or near-infrared bands, and the cross-sectional structure of the hollow anti-resonant fiber includes a five-hole or six-hole structure, which is used to form a broadband gas-absorbing optical waveguide.

[0019] In some possible embodiments, the gas exchange acceleration module is a miniature air pressure regulating device connected to the air inlet and / or air outlet of the gas absorption chamber.

[0020] In some possible embodiments, the optical fiber connection structure is a multi-channel fluid connector used to achieve mechanical docking and air circuit connection between the input optical fiber, the output optical fiber and the hollow anti-resonant optical fiber.

[0021] Alternatively, the fiber optic connection structure is a fusion splice, and a vent is provided on the sidewall near the fusion splice of the hollow anti-resonant fiber.

[0022] In some possible embodiments, when the optical fiber connection structure is a multi-channel fluid connector, slits are reserved between the two ends of the hollow anti-resonant optical fiber and the end faces of the input and output optical fibers, so that the gas absorption cavity can be connected to the external environment gas path through the multi-channel fluid connector.

[0023] In some possible embodiments, the signal demodulation module employs wavelength modulation spectroscopy and second harmonic detection techniques, using the frequency of the composite modulation signal as a reference frequency, to demodulate the second harmonic signal reflecting the gas concentration from the electrical signal as an absorption characteristic signal.

[0024] In some possible embodiments, the output wavelengths of at least two tunable lasers correspond to the characteristic absorption lines of at least two different gas molecules.

[0025] In some possible embodiments, the input fiber and the output fiber are single-mode fibers in the output band of a tunable laser.

[0026] The beneficial effects of the technical solutions provided by some embodiments of the present invention include at least the following: by integrating a micro pressure regulating device to forcibly accelerate the exchange of gas within the hollow anti-resonant fiber microcavity, the problem of slow response in traditional fiber optic sensing is solved; by utilizing the characteristics of wide-spectrum hollow fiber supporting ultraviolet / near-infrared multi-band transmission, combined with multi-path independent modulation laser beam combining and phase-locked harmonic demodulation technology, synchronous, in-situ, and high-sensitivity detection of multiple gas components is achieved; the all-fiber integrated structure eliminates complex spatial optical paths, improves the system's compactness, environmental stability, and anti-interference capability, and ultimately forms a gas sensing solution that combines fast response, multi-parameter synchronous measurement, wide dynamic range, and high reliability, which can effectively meet the real-time and accurate monitoring needs of scenarios such as battery safety early warning and industrial leak monitoring. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A system architecture diagram of a multi-component gas concentration detection system based on hollow anti-resonant optical fiber provided in an embodiment of the present invention;

[0029] Figure 2 An exemplary system architecture diagram of a multi-component gas concentration detection system based on hollow anti-resonant optical fiber provided in this statement embodiment;

[0030] Figure 3 A cross-sectional view of a hollow anti-resonant optical fiber provided in an embodiment of the present invention;

[0031] Figure 4 The transmission loss and transmission spectrum of a hollow anti-resonant optical fiber are provided in this embodiment of the invention.

[0032] Figure 5 A schematic diagram of the interaction between gas and light in a hollow chamber provided in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of a gas response test result provided in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of an industrial mixed gas leakage test provided in an embodiment of the present invention. Detailed Implementation

[0035] To make the features and advantages of the present invention more apparent and understandable, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0037] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0038] As mentioned earlier, to address the challenge of balancing response speed, multi-component simultaneous detection capability, system integration, and detection performance in existing gas sensing technologies, this invention provides a multi-component gas concentration detection system based on hollow-core anti-resonant optical fiber. The system aims to overcome the slow response of traditional fiber optic sensing by integrating a micro-pressure regulating device to forcibly accelerate gas exchange within the microcavity of the hollow-core anti-resonant optical fiber. Utilizing the wide-spectrum hollow-core optical fiber's ability to support ultraviolet / near-infrared multi-band transmission, combined with multi-path independent modulation laser beam combining and phase-locked harmonic demodulation technology, it achieves simultaneous, in-situ, and highly sensitive detection of multiple gas components. The all-fiber integrated structure eliminates complex spatial optical paths, improving system compactness, environmental stability, and anti-interference capabilities. Ultimately, this results in a gas sensing solution that combines rapid response, simultaneous multi-parameter measurement, wide dynamic range, and high reliability, effectively meeting the real-time and accurate monitoring needs of scenarios such as battery safety early warning and industrial leak monitoring.

[0039] Please see Figure 1 , Figure 1 This is a system architecture diagram of a multi-component gas concentration detection system based on hollow anti-resonant optical fiber, provided as an embodiment of the present invention. Figure 1As shown, the multi-component gas concentration detection system 100 based on hollow-core anti-resonant optical fiber includes a signal generation module 101, a laser emission module 102, an optical fiber coupling module 103, an input optical fiber 104, a gas chamber module 105, a gas exchange acceleration module 106, an output optical fiber 107, a photoelectric conversion module 108, a signal demodulation module 109, and a data processing module 110. In this embodiment, the signal generation module 101 generates multiple independent composite modulation signals, each signal driving a tunable laser corresponding to a laser emission module 102. The output wavelengths of at least two tunable lasers correspond to the characteristic absorption lines of at least two different gas molecules. The laser emission module 102 includes at least two tunable lasers, preferably distributed feedback lasers, which, driven by corresponding current drivers, output narrow-linewidth continuous laser beams with wavelengths corresponding to the characteristic absorption peaks of different target gases in the ultraviolet or near-infrared bands. It receives composite modulation signals and outputs narrow-linewidth scanning beams with wavelengths corresponding to the characteristic absorption peaks of different gases. The fiber optic coupling module 103 combines the beams output from at least two tunable lasers into a single composite beam. The combined beam is coupled into the gas chamber module 105 via the input fiber 104. The gas chamber module 105 includes a hollow-core anti-resonant fiber. Both ends of the hollow-core anti-resonant fiber are connected to the input fiber 104 and the output fiber 107 respectively via fiber optic connection structures. The hollow core of the hollow-core anti-resonant fiber forms a gas absorption cavity to contain the gas to be measured and to interact with the composite beam through absorption. The hollow-core anti-resonant fiber operates in the ultraviolet and / or near-infrared bands. Its cross-sectional structure includes a five-hole or six-hole structure to form a broadband gas absorption waveguide. Both ends of the hollow-core anti-resonant fiber are fixed by rigid sleeves (ceramic ferrules, metal sleeves, polymer-bonded sleeves, etc.) and are connected to the input / output single-mode fibers and the gas path via self-made multi-channel fluid connectors (T-type, Y-type, etc.). A miniature gas pressure regulating device is integrated into the gas path end. The input and output optical fibers are single-mode fibers in the output band of the tunable laser. The fiber connection structure is a multi-channel fluid connector, used to achieve mechanical docking and gas path communication between the input and output optical fibers and the hollow anti-resonant fiber; alternatively, the fiber connection structure can also be in the form of a fusion splice, with a vent hole on the sidewall near the fusion splice of the hollow anti-resonant fiber. It should be noted that when the fiber connection structure is a multi-channel fluid connector, slits are reserved between the two ends of the hollow anti-resonant fiber and the end faces of the input and output optical fibers to allow the gas absorption cavity to communicate with the external environment's gas path through the multi-channel fluid connector. The gas exchange acceleration module 106, located on the gas path of the gas absorption cavity, is used to regulate the gas pressure to accelerate the gas replacement within the gas absorption cavity. The gas exchange acceleration module is a miniature gas pressure regulating device connected to the inlet and / or outlet of the gas absorption cavity.The photoelectric conversion module 108 receives the emitted light after gas absorption and converts it into an electrical signal. The signal demodulation module 109 uses a composite modulation signal as a reference to perform harmonic demodulation on the electrical signal and extract the absorption characteristic signals corresponding to each gas. The signal demodulation module uses wavelength modulation spectroscopy and second harmonic detection technology, using the frequency of the composite modulation signal as a reference frequency, to demodulate the second harmonic signal reflecting the gas concentration from the electrical signal as the absorption characteristic signal. The data processing module 110 calculates the concentration value corresponding to each gas based on the absorption characteristic signal. In one specific embodiment, the composite modulation signal generated by the signal generation module 101 drives the laser emission module 102, outputting scanning light with wavelengths corresponding to the characteristic absorption peaks of different target gases in the ultraviolet or near-infrared bands. After being combined by the fiber coupling module 103, the multiple laser beams are introduced into the gas absorption chamber of the hollow anti-resonant fiber of the gas chamber module 105 through the input fiber 104. Inside the absorption chamber, the laser interacts with the gas molecules in the cavity through the gas exchange acceleration module 106, and the light intensity is selectively absorbed. The emitted light carrying absorption information is output from the output optical fiber 107, converted into an electrical signal by the optical fiber conversion module 108, and then demodulated by the signal demodulation module 109 with the modulation frequency as a reference to extract the second harmonic of each gas. Finally, the data processing module 110 processes and records the second harmonic in real time to deduce the concentration value of each gas. The integrated micro pressure regulating device effectively accelerates the gas exchange process in the absorption chamber, thereby significantly improving the system's response speed.

[0040] Please see Figure 2 , Figure 2 An exemplary system architecture diagram of a multi-component gas concentration detection system based on hollow anti-resonant optical fiber, provided in this statement embodiment, is shown below. Figure 2 As shown, the system includes a signal generator 1, a tunable laser 2, an optical fiber coupler 3, an input optical fiber 4, an output optical fiber 5, a hollow-core anti-resonant optical fiber 6, a photodetector 7, a lock-in amplifier 8, a computer 9, a multi-channel fluid connector 10, an air inlet 11-1, an air outlet 11-2, and a miniature air pressure regulating device 12. The hollow-core anti-resonant optical fiber 6 is fixed at both ends by rigid sleeves and is connected to the input optical fiber 4 and the output optical fiber 5, as well as the air inlet 11-1 and the air outlet 11-2, via the self-made multi-channel fluid connector 10. The miniature air pressure regulating device 12 is integrated at both the air inlet 11-1 and the air outlet 11-2. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 A cross-sectional view of a hollow anti-resonant optical fiber provided in an embodiment of the present invention, as shown below. Figure 3 As shown in (A), the hollow anti-resonant fiber includes a near-infrared six-hole hollow anti-resonant fiber. Figure 3 As shown in (B), the hollow-core anti-resonant fiber includes a near-infrared five-hole hollow-core anti-resonant fiber. Figure 3 As shown in (C), hollow-core antiresonant optical fibers include ultraviolet six-hole hollow-core antiresonant optical fibers. Specifically, the near-infrared six-hole hollow-core antiresonant optical fiber has a hollow core diameter of 40 micrometers and an outer cladding diameter of 200 micrometers; the near-infrared five-hole hollow-core antiresonant optical fiber has a hollow core diameter of 35 micrometers and an outer cladding diameter of 180 micrometers; and the ultraviolet six-hole hollow-core antiresonant optical fiber has a hollow core diameter of 40 micrometers and an outer cladding diameter of 166 micrometers. All three types of fibers have high-purity silica cladding. Based on the antiresonant reflection waveguide effect, a hollow waveguide is achieved. Hollow-core antiresonant optical fibers have advantages such as large core size and wide transmission range. Please refer to [link / reference]. Figure 4 , Figure 4 The transmission loss and transmission spectrum of a hollow antiresonant optical fiber provided in this embodiment of the invention are as follows: Figure 4 As shown, the corresponding optical fibers are a six-hole hollow-core anti-resonant fiber, a five-hole hollow-core anti-resonant fiber, and a six-hole hollow-core anti-resonant fiber, respectively. The operating wavelengths of the six-hole hollow-core anti-resonant fiber are 650-700nm and 1400-170nm; the operating wavelengths of the five-hole hollow-core anti-resonant fiber are 850-1000nm and 1450-1550nm; and the operating wavelengths of the six-hole hollow-core anti-resonant fiber are 350-400nm, 520-550nm, and 1020-1120nm. When the two ends of the hollow-core anti-resonant fiber 6 are connected to the input fiber 4 and the output fiber 5, a 100-micron slit is reserved between them to allow the gas chamber to form a communication path with the external gas to be measured. The input fiber 4 and output fiber 5 are commercial ultraviolet and near-infrared single-mode fibers. The output fiber 5 guides the emitted light, after absorption by the gas, into the photodetector 7. The photodetector 7, lock-in amplifier 8, and computer 9 are connected in sequence for signal conversion, harmonic demodulation, and data acquisition. Besides using a multi-channel fluid connector 10 to connect the input fiber, hollow-core anti-resonant fiber, and output fiber, fusion splicing can also be used. After fusion splicing, holes are drilled in the hollow-core fiber, and the drilled portion is placed in the gas chamber 13. When the system is placed in the gas to be measured, the multi-channel laser interacts with the gas molecules in the gas chamber, and the light intensity is selectively absorbed. Designing large-size optical fibers can effectively increase the interaction between the gas and light. The emitted light carrying absorption information is converted into an electrical signal by the photodetector, and then demodulated by the lock-in amplifier 8 with the modulation frequency as a reference, extracting the second harmonic of each gas. The computer 9 processes and records the second harmonics in real time, retrieving the concentration value of each gas. The miniature pressure regulating device 12 effectively accelerates the gas exchange process in the absorption chamber, thereby significantly improving the system's response speed.

[0041] In one possible embodiment, this system can perform real-time concentration monitoring and dynamic response analysis of the gases released during battery operation to ensure the health and safety of the battery, and effectively capture the abrupt transition of the battery from normal operating conditions to abnormal conditions. Please refer to [link / reference]. Figure 5 , Figure 5A schematic diagram of the interaction between gas and light in a hollow chamber provided as an embodiment of the present invention, such as... Figure 5 As shown, the target battery covers Figure 5 The three typical structural forms shown are: Cylindrical battery 1: adopts a modular and standardized design, typical examples include but are not limited to specifications such as 18mm diameter / 65mm height (18650 type), 21mm diameter / 70mm height (21700 type), and 46mm diameter / 80mm height (4680 type), etc., with a flexible guide tube embedded inside the battery to achieve gas permeation and collection through a microporous structure; Soft-pack battery 4-2: achieves gas adsorption and enrichment through an external flexible gas collection bag; Square battery 4-3: connects to the battery cavity through a perforated guide tube, combined with a sealed interface to achieve gas exhaust. These typical structural forms of batteries refer to alkali metal ion batteries, such as but not limited to lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries.

[0042] In one possible embodiment, this system can be used to detect methane ( ) and acetylene ( (Gas). Specifically, tunable lasers with center wavelengths of 1532.68 nm and 1653.73 nm are used to interact with acetylene and methane gas molecules, respectively. The gas molecules selectively absorb the laser light, and a lock-in amplifier demodulates the absorption signal, extracting the second harmonic of each gas to deduce the concentration of acetylene and methane. Please refer to [link to relevant documentation]. Figure 6 , Figure 6 This diagram illustrates a gas response test result provided in an embodiment of the present invention. The test results show that the amplitudes of the second harmonic signals of methane and acetylene exhibit a good linear relationship with their respective concentrations, with linear fitting determination coefficients R² reaching 0.9995 and 0.9996, respectively. The detection sensitivity for methane was measured to be 0.0006 / V / ppm, while the sensitivity for acetylene was 0.0019 / V / ppm. This system is free from... Its response time is approximately 9.4 seconds and its recovery time is 8 seconds, indicating that it has a fast response capability.

[0043] In one possible embodiment, the system can be used to detect gas leaks in industrial pipelines. These industrial pipelines contain methane (…). ) and acetylene ( A mixed gas has a 0.5mm leak in the pipeline. The system inlet is fixed to a displacement platform, which is then scanned back and forth along the pipeline direction (defined as the x-axis) at a speed of 0.2mm / s and a step size of 0.2mm, from the initial position to the end of the pipeline. Please refer to... Figure 7 , Figure 7 This is a schematic diagram of an industrial mixed gas leakage test provided in an embodiment of the present invention, as shown below. Figure 7As shown, the highest concentration point corresponds to the center of the leak: the gas concentration is highest when the system is close to the leak point, and decreases as it moves away, exhibiting a symmetrical distribution from left to right and from right to left. This is due to the free diffusion effect of the gas, i.e., high concentration at the center and low concentration at the edges. Experimental results show that this system can be effectively used for detecting the concentration of mixed leaked gases in industrial environments and can accurately locate the leak point. This system is not limited to one-dimensional linear scanning; it can also be used for two-dimensional planar scanning and three-dimensional spatial scanning to visualize the shape of the leak and the evolution of the gas at the leak point.

[0044] This invention provides a multi-component gas concentration detection system based on hollow-core anti-resonant optical fiber. By integrating a micro pressure regulating device to forcibly accelerate gas exchange within the microcavity of the hollow-core anti-resonant optical fiber, it solves the problem of slow response in traditional optical fiber sensing. Utilizing the characteristics of wide-spectrum hollow-core optical fiber supporting ultraviolet / near-infrared multi-band transmission, combined with multi-path independent modulation laser beam combining and phase-locked harmonic demodulation technology, it achieves synchronous, in-situ, and highly sensitive detection of multiple gas components. The all-fiber integrated structure eliminates complex spatial optical paths, improving the system's compactness, environmental stability, and anti-interference capability. Ultimately, it forms a gas sensing solution that combines fast response, simultaneous measurement of multiple parameters, wide dynamic range, and high reliability, effectively meeting the real-time and accurate monitoring needs of scenarios such as battery safety early warning and industrial leak monitoring.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-component gas concentration detection system based on hollow-core anti-resonant optical fiber, characterized in that, The system includes: Signal generation module, laser emission module, fiber optic coupling module, input fiber, gas chamber module, gas exchange acceleration module, output fiber, photoelectric conversion module, signal demodulation module, and data processing module; The signal generation module is used to generate independent composite modulation signals; The laser emitting module includes at least two tunable lasers, which respectively receive the composite modulation signal and output narrow linewidth scanning beams with wavelengths corresponding to the characteristic absorption peaks of different gases. The fiber optic coupling module is used to combine the beams output from the at least two tunable lasers into a composite beam. The gas chamber module includes a hollow anti-resonant optical fiber. The two ends of the hollow anti-resonant optical fiber are respectively connected to the input optical fiber and the output optical fiber through optical fiber connection structures. The hollow core of the hollow anti-resonant optical fiber forms a gas absorption cavity, which is used to contain the gas to be measured and to have absorption interaction with the composite light. The gas exchange acceleration module is located in the gas path of the gas absorption chamber and is used to adjust the gas pressure in the gas path to accelerate the replacement of gas in the gas absorption chamber. The photoelectric conversion module is used to receive the emitted light after it has been absorbed by the gas and convert it into an electrical signal; The signal demodulation module is used to perform harmonic demodulation on the electrical signal with the composite modulation signal as a reference, and extract the absorption characteristic signals corresponding to each gas. The data processing module is used to calculate the concentration value of each gas based on the absorption characteristic signal.

2. The system as described in claim 1, characterized in that, The hollow anti-resonant fiber is a hollow anti-resonant fiber that operates in the ultraviolet and / or near-infrared bands. The cross-sectional structure of the hollow anti-resonant fiber includes a five-hole or six-hole structure, which is used to form a broadband gas-absorbing optical waveguide.

3. The system as described in claim 1, characterized in that, The gas exchange acceleration module is a miniature air pressure regulating device connected to the air inlet and / or air outlet of the gas absorption chamber.

4. The system as described in claim 1, characterized in that, The optical fiber connection structure is a multi-channel fluid connector, used to realize the mechanical docking and air circuit connection between the input optical fiber, the output optical fiber and the hollow anti-resonant optical fiber. Alternatively, the optical fiber connection structure is a fusion splice, and a vent hole is provided on the sidewall near the fusion splice of the hollow anti-resonant optical fiber.

5. The system as described in claim 4, characterized in that, When the optical fiber connection structure is a multi-channel fluid connector, a slit is reserved between the two ends of the hollow anti-resonant optical fiber and the end faces of the input and output optical fibers, so that the gas absorption cavity can be connected to the external environment gas path through the multi-channel fluid connector.

6. The system as described in claim 1, characterized in that, The signal demodulation module employs wavelength modulation spectroscopy and second harmonic detection technology. Using the frequency of the composite modulation signal as a reference frequency, it demodulates the second harmonic signal reflecting the gas concentration from the electrical signal as the absorption characteristic signal.

7. The system as described in claim 1, characterized in that, The output wavelengths of the at least two tunable lasers correspond to the characteristic absorption lines of at least two different gas molecules.

8. The system as described in claim 1, characterized in that, The input fiber and the output fiber are single-mode fibers in the output band of the tunable laser.

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