Hydrogen-sensitive sensor based on coaxial opposite side parallel optical fiber F-P cavity and spectrograph detection system

Abstract

The invention discloses a hydrogen-sensitive sensor based on coaxial opposite side parallel optical fiber F-P cavities and a spectrograph detection system, relates to the technical field of optical fiber sensing, and aims to solve the problems of insufficient structural stability, overlong response time of a diffusion channel and weak matching performance of a detection system in the prior art. The two ends of the sleeve are provided with insertion cores, and the two insertion cores and the sleeve define an F-P cavity. A single-mode optical fiber and a quartz capillary tube are also arranged in the sleeve; a palladium metal hydrogen sensitive film is arranged at the end, opposite to the F-P cavity, of the insertion core; sealing materials are filled between the insertion core and the single-mode optical fiber, between the insertion core and the sleeve and between the insertion core and the quartz capillary, the zirconia ceramic insertion core and the sleeve are coaxially assembled, the distance between the insertion cores is calibrated in combination with a digital display caliper, gaps are sealed through CER500 epoxy resin, cavity length drifting caused by vibration and temperature change is effectively restrained, and long-term detection repeatability is effectively improved. The low expansion coefficient of the ceramic material can reduce the influence of temperature change on the cavity length, and the anti-interference performance of the structure is optimized.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, in particular to a hydrogen-sensitive sensor and a spectrometer detection system based on a coaxial, opposite, and laterally parallel optical fiber FP cavity. Background Art

[0002] As hydrogen energy applications expand, hydrogen leak monitoring has become central to the safe operation and maintenance of hydrogen storage facilities. Traditional detection technologies have significant limitations: electrochemical sensors are susceptible to environmental interference, requiring regular electrolyte replacement and lacking safety; semiconductor sensors have low sensitivity and poor stability; and gas chromatography requires offline operation and is unable to respond to rapid leaks.

[0003] Fiber-optic sensing technology has become a key development direction due to its advantages such as resistance to electromagnetic interference and inherent safety. Optical fiber-optic hydrogen sensors have attracted considerable attention, but they face challenges in response speed, stability, sensitivity, and cost. While research on fiber-optic hydrogen sensors has made progress, their application remains limited.

[0004] Fiber optic sensors based on the Fabry-Perot (FP) interferometry principle have been widely studied. However, existing FP hydrogen-sensitive sensors have key problems: insufficient structural stability, low initial cavity length control accuracy, prone to cavity length drift, and alignment deviation between the optical fiber and the Pd film affecting the signal; the hydrogen-sensitive film preparation process needs to be optimized, the palladium film thickness uniformity is poor, and the bonding strength with the ferrule is weak; the hydrogen diffusion efficiency is low, and the diffusion channel parameters are not optimized, resulting in a long response time; the detection system has weak matching, high welding loss, and insufficient spectrometer resolution, which affects the detection accuracy.

[0005] Therefore, there is an urgent need to develop optical fiber FP hydrogen-sensitive sensors and supporting detection systems with compact structure, fast response and stable sensitivity. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the existing defects and provide a hydrogen-sensitive sensor and spectrometer detection system based on coaxial opposite side parallel optical fiber FP cavity, which can effectively solve the problems in the background technology.

[0007] To achieve the above-mentioned object, the present invention discloses a hydrogen-sensitive sensor based on a coaxial, opposite-side, parallel optical fiber FP cavity. The technical solution adopted is as follows: the sensor comprises a ferrule and a sleeve. The sleeve is a shell with two transparent ends. The ferrules are provided at both ends of the sleeve. Two groups of the ferrules and the sleeve enclose an FP cavity. A group of the ferrules is located at the left end of the sleeve, and a single-mode optical fiber is provided between the ferrule and the sleeve, and the right end of the single-mode optical fiber is connected to the FP cavity; Another group of the ferrules is located at the right end of the sleeve, and a quartz capillary is provided between the ferrule and the sleeve, the quartz capillary is provided with a hydrogen diffusion hole, and a plugging material is provided at the end of the quartz capillary facing the FP cavity; A palladium metal hydrogen-sensitive film is provided between the ferrule at the right end and the facing end of the FP cavity; sealing material is provided between the ferrule and the single-mode optical fiber, the sleeve and the quartz capillary. By adopting a zirconia ceramic ferrule and the sleeve for coaxial assembly, the ferrule spacing is calibrated in combination with a digital caliper, and the gap is sealed with CER500 epoxy resin, the cavity length drift caused by vibration and temperature change is effectively suppressed, and the long-term detection repeatability is effectively improved; the low expansion coefficient of the ceramic material can reduce the influence of temperature change on the cavity length and optimize the anti-interference performance of the structure.

[0008] As a preferred technical solution of the present invention, the sealing material and the plugging material are both made of CER500 epoxy resin.

[0009] As a preferred technical solution of the present invention, a chromium metal film is further provided between the insert and the palladium metal hydrogen-sensitive film. The palladium film is prepared by a magnetron sputtering process (first plating a 5nm chromium stabilization layer, then plating a 70nm palladium film), and the thickness uniformity error is ≤±5nm. When hydrogen is absorbed, the entire cylindrical palladium film on the end surface of the insert expands proportionally, avoiding signal discreteness caused by local expansion differences. The low concentration (0-4%) detection sensitivity is approximately 0.554nm / %.

[0010] As a preferred technical solution of the present invention, the hydrogen diffusion hole is an isosceles triangle, which is opened on the facing surface of the quartz capillary and the ferrule, and corresponds to the position of the palladium metal hydrogen sensitive film and the chromium metal film. The side wall of the quartz capillary is opened with a small isosceles triangle opening with a height of 0.1mm and a bottom of 0.2mm, which is close to one end of the palladium metal hydrogen sensitive film, shortening the hydrogen diffusion path, and with the optimized inner diameter hydrogen flow rate ≥15mL / min, the 4% explosion concentration response time ≤185s, which is more suitable for rapid leakage warning scenarios.

[0011] As a preferred technical solution of the present invention, the right end of the single-mode optical fiber is cut into a flat end face using a fiber cleaver, and the inclination angle of the end face is less than 1°, and the right end of the single-mode optical fiber is polished to form a reflector.

[0012] As a preferred technical solution of the present invention, the single-mode optical fiber and the quartz capillary are distributed in a mirror-image manner within the sleeve.

[0013] A spectrometer detection system adopts a technical solution comprising a test box and a hydrogen-sensitive sensor, wherein the hydrogen-sensitive sensor is installed in the test box, and a pigtail of the hydrogen-sensitive sensor protrudes from the test box through a fiber outlet hole; The pigtail is connected to the second interface of the three-port circulator through an optical fiber flange connector, the first interface of the three-port circulator is connected to a laser source, the third interface of the three-port circulator is connected to a spectrometer, and the spectrometer is connected to a computer through a host computer; The top of the test box is connected to a hydrogen injection syringe through an air valve, and the output end of the hydrogen injection syringe is located inside the test box. A fan is also provided inside the test box; A vent is provided on the side wall of the test box. A hose is provided in the vent. One end of the hose is connected to the interior of the test box, and the other end is connected to a combustible gas concentration detector.

[0014] As a preferred technical solution of the present invention, the test box includes a base and a box cover. The base is a shell with a transparent top surface. The top of the base is connected to the box cover by a buckle. A sealing ring is also provided between the box cover and the base.

[0015] As a preferred technical solution of the present invention, the three interfaces of the three-port circulator are respectively connected to the laser source, the fiber flange connector and the spectrometer through single-mode optical fibers.

[0016] Compared with the prior art, the present invention has the beneficial effect of having strong structural stability: by adopting a zirconia ceramic ferrule and a coaxial assembly with a sleeve, combining a digital caliper to calibrate the ferrule spacing, and sealing the gap with CER500 epoxy resin, the cavity length drift caused by vibration and temperature change is effectively suppressed, and the long-term detection repeatability is effectively improved; the low expansion coefficient of the ceramic material can reduce the influence of temperature changes on the cavity length, and optimize the anti-interference performance of the structure.

[0017] The present invention has a fast response speed: a small isosceles triangle opening with a height of 0.1mm and a bottom of 0.2mm is opened on the side wall of the quartz capillary, which is close to one end of the palladium metal hydrogen sensitive film, shortening the hydrogen diffusion path. Combined with the optimized inner diameter, the hydrogen flow rate is ≥15mL / min, and the response time of 4% explosion concentration is ≤185s, which is more suitable for rapid leakage warning scenarios.

[0018] The palladium metal hydrogen-sensitive film of the present invention has high expansion consistency: the palladium film is prepared by a magnetron sputtering process (first plating a 5nm chromium stabilization layer, then plating a 70nm palladium film), and the thickness uniformity error is ≤±5nm. When hydrogen is absorbed, the entire cylindrical palladium film on the end face of the insert expands proportionally, avoiding signal discreteness caused by local expansion differences. The low concentration (0-4%) detection sensitivity is approximately 0.554nm / %.

[0019] The present invention has good stability for internal and external transmission signals: the quartz capillary end in the FP cavity is sealed by CER500 epoxy resin dispensing, which can prevent external light leakage and noise interference in the cavity, ensure the relative stability of the interference spectrum signal, and reduce the spectral baseline drift in long-term operation, significantly improving detection reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the hydrogen sensitive sensor of the present invention; Figure 2 This is the SEM morphology of the surface of the palladium metal hydrogen sensitive film of the hydrogen sensitive sensor of the present invention; Figure 3 Schematic diagram of the spectrometer detection system of the present invention; Figure 4 This is a schematic diagram of the structure of the test box of the spectrometer detection system of the present invention; Figure 5 This is the FP interference spectrum of the hydrogen sensitive sensor of the present invention when the hydrogen gas volume fraction is within the range of 0-3%; Figure 6 This is a fitting diagram showing the relationship between the wavelength drift of the nearest trough value (position 1548.600nm) of the FP interference center wavelength 1550nm and the hydrogen gas integral fraction when the hydrogen concentration of the hydrogen sensitive sensor of the present invention is 0-3.5% (step size 0.5%).

[0021] Figure: 1, ferrule; 2, sleeve; 3, chromium metal film; 4, palladium metal hydrogen-sensitive film; 5, single-mode optical fiber; 51, reflector; 6, sealing material; 7, quartz capillary; 8, hydrogen diffusion hole; 9, plugging material; 10, FP cavity; 11. Hydrogen sensor; 111. Pigtail; 12. Test box; 121. Base; 122. Vent; 123. Lock; 124. Box cover; 125. Air valve; 126. Hydrogen injection syringe; 127. Fan; 128. Fiber outlet; 13. Three-port circulator; 131. First interface; 132. Second interface; 133. Third interface; 14. Laser source; 15. Fiber optic flange connector; 16. Spectrometer; 17. Host computer; 18. Computer; 19. Hose; 20. Combustible gas concentration detector. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example 1

[0023] like Figures 1 to 2 As shown, the present invention discloses a hydrogen-sensitive sensor based on a coaxial, side-mounted, parallel optical fiber FP cavity, so as to improve the sensitivity, stability, and anti-interference of hydrogen-sensitive detection and simplify the hydrogen-sensitive sensor to make it more compact.

[0024] The adopted technical solution is to include a ferrule 1, which is provided with two groups and is made of zirconia ceramic with a flat end surface; Sleeve 2, made of zirconia ceramic with a smooth inner wall; Chromium metal film 3, with a thickness of 5 nm; Palladium metal hydrogen sensitive film 4, with a thickness of 70 nm; Single-mode optical fiber 5, after being processed with a fiber cleaver, ensure that the end face is flat and the inclination angle of the end face is less than 1°; The reflector 51 has been polished several times to achieve a smooth fiber end face. Sealing material 6, using CER500 epoxy resin to fill the gap; Quartz capillary 7, length 3 mm; The hydrogen diffusion hole 8 is an isosceles triangle with a height of 0.1 mm and a base of 0.2 mm, and is provided on the quartz capillary 7; The sealing material 9 is made of CER500 resin, which is glued to seal one end of the quartz capillary 7; The FP cavity 10 has a length of 80 μm.

[0025] The specific preparation steps of the hydrogen sensitive sensor 11 are as follows: Pre-treat the ferrule 1 and cannula 2. Select a ferrule 1 with a polished outer diameter of 2.0 mm ± 0.01 mm and a length of 8 mm ± 0.01 mm, and a cannula 2 with a polished inner wall of 2.5 mm ± 0.01 mm, an outer diameter of 6 mm ± 0.01 mm, and a length of 4 mm ± 0.01 mm. Clean the ferrule 1 and cannula 2 with anhydrous ethanol to remove surface impurities and dry them for later use.

[0026] A single-mode optical fiber 5, treated with a fiber cleaver to ensure a smooth end face, was assembled with a 3mm quartz capillary 7. The single-mode optical fiber 5 had a core diameter of 9μm and a cladding diameter of 125μm. The fiber cleaver was used to cut the end face to a smooth surface (end face tilt angle ≤ 1°). The quartz capillary 7 had an inner diameter of 250μm ± 12μm, an outer diameter of 370μm ± 10μm, and a length of 3mm ± 0.1mm. An isosceles triangular hydrogen diffusion hole 8, 0.1mm high and 0.2mm low, was opened in its sidewall to serve as the hydrogen inlet. A single-mode optical fiber 5 with a highly smooth end face (to ensure high reflectivity) that has been polished multiple times is affixed to the side of the ferrule 1 along the axial direction thereof, along with a quartz capillary 7. The two are mirror-imaged at both ends of the cross-sectional diameter. CER500 epoxy resin sealing material 6 is used to secure and seal the gap, ensuring that the reflector 51 on the optical fiber end face is flush with the end face of the ferrule 1. The hydrogen diffusion hole 8 of the quartz capillary 7 faces outward, away from the FP cavity 10. CER500 epoxy resin sealing material 9 is dripped into the end of the quartz capillary 7 inside the FP cavity 10 using a dispensing needle to seal the end.

[0027] After the initial pasting process, the two ferrules 1 are coaxially assembled in the sleeve 2, and the distance between the ferrules 1 is calibrated using a digital caliper (resolution 0.01mm) to form an FP cavity 10 with an initial cavity length of 80μm±0.01mm. Figure 1 As shown, the assembly end face of the right end ferrule 1 was sequentially deposited with a magnetron sputtering process to deposit a 5nm chromium metal film 3 (target purity ≥99.99%, sputtering power 80W) and a 70nm palladium metal hydrogen sensitive film 4 (target purity ≥99.99%, sputtering power 100W). The step profiler test showed that the thickness uniformity error of the palladium metal hydrogen sensitive film 4 was ≤±5nm, the surface palladium particles were evenly distributed, the surface was smooth and clean, and the structure was dense (see attached). Figure 2 As shown in FIG. 1 ). Light emitted by a laser source 14 is transmitted via a single-mode optical fiber 5 into the FP cavity 10 enclosed by the two ferrules 1 and the sleeve 2. The left ferrule 1 has a flat ceramic end face for supporting and fixing a reflector 51 that secures a highly smooth, vertical, and flat optical fiber end face. The right ferrule 1 has a flat, highly reflective palladium metal hydrogen-sensitive film 4 magnetron-sputtered on its end face. Both the optical fiber end face and the palladium film serve as the reflector 51. Light is reflected from the two reflective surfaces, generating two beams of reflected light. These two beams interfere due to the optical path difference and together form the FP cavity 10 (based on the principle of dual-beam interference). When hydrogen gas contacts the palladium metal hydrogen-sensitive film 4, the palladium film absorbs hydrogen atoms, causing it to expand, resulting in a change in the length of the FP cavity 10. This change is used to sense changes in hydrogen concentration and cause changes in the cavity length.

[0028] Finally, seal and cure the structure. Use CER500 epoxy resin to fill the gap between the ferrule 1 and the sleeve 2 and cure it at room temperature for half an hour to ensure that the structure is stable and there is no light leakage.

[0029] like Figures 3 to 6 As shown, the present invention discloses a spectrometer detection system to achieve high-resolution spectral demodulation, improve the sensitivity and stability of hydrogen-sensitive detection, and meet real-time monitoring needs.

[0030] The technical solution adopted is: The test box 12 includes a box cover 124 and a base 121, and is made of acrylic material. The volume of the box is 18L; The test box 12 has two vent holes 122 with plastic plugs. One vent hole 122 is located on the side wall of the base 121 for inserting the hose 19. The other vent hole is located on the box cover 124 for slowly releasing hydrogen from the test box 12. Eight stainless steel locks 123 for securing the lid 124 to the base 121; an acrylic box cover 124 with a sealing ring attached; The box cover 124 is provided with a Q11SA-PN6.4 1 / 4 304 model gas valve 125, which is used to receive hydrogen gas inputted from a 100ml hydrogen injection syringe 126; A low-voltage fan 127 is fixed in the test box 12 to promote the rapid and uniform diffusion of the introduced hydrogen to prevent the occurrence of excessive hydrogen concentration at a certain location; The test box 12 has a fiber outlet 128 for sealing the pigtail 111 of the hydrogen sensor 11 after it is ejected from the test box 12 to prevent air leakage. A three-port circulator 13 , wherein the three-port circulator 13 has a first port 131 (red line), a second port 132 (blue line), and a third port 133 (white line); a laser source 14 capable of emitting C-band light; Several fiber optic flange connectors 15 are used for low-loss connectivity detection systems. An MS9740A spectrometer 16 is directly connected to the pigtail 111 of the hydrogen sensitive sensor 11. The spectrometer 16 displays the spectrum data in real time and imports it into the computer 18 through the host computer 17. A plastic gas hose 19 connects the test box 12 with a portable combustible gas concentration detector 20 (range 0-100%LEL) to calibrate the hydrogen concentration in the test box 12 in real time.

[0031] As attached Figure 4 As shown, the test box 12 is an acrylic box with a volume of 18L (dimensions: 300mm×300mm×200mm). The box cover 124 is provided with a syringe hydrogen injection port (equipped with a 100ml hydrogen injection syringe 126), a gas valve 125 (Q11SA-PN6.4 1 / 4 304 model), and a fiber outlet 128 for leading out the pigtail 111. A low-voltage fan 127 is installed on the inner wall to promote uniform diffusion of hydrogen and prevent local excessive concentration.

[0032] The hydrogen sensor 11 is fixed to the hydrogen injection area at the top of the test box 12 by a support device. The support device is a 15 cm high support frame used to support the hydrogen sensor 11, so that the hydrogen sensor 11 is placed relatively high in the internal space of the test box 12 to prevent the situation where the hydrogen concentration below cannot be detected when it is too low.

[0033] A C-band laser source 14 (central wavelength 1550 nm, output power approximately 10 mW) is connected to the first port 131 (red line) of the three-port circulator 13 via a single-mode optical fiber 5 (FC / APC interface). The second port 132 (blue line) is fused to the pigtail 111 via a fiber flange connector 15 (fusion loss ≤ 0.1 dB). The third port 133 (white line) is connected to the MS9740A spectrometer 16.

[0034] A portable combustible gas concentration detector 20 is connected to the vent 122 via a plastic hose 19, allowing real-time calibration of the hydrogen concentration within the chamber. A spectrometer 16 displays the recorded data in real time and imports it into a host computer 17 and computer 18. The data is then demodulated using both single-peak tracking (locking onto a reference trough near 1550nm and dynamically tracking its wavelength shift) and double-peak tracking (analyzing adjacent peaks to calculate the free spectral range (FSR)) for dual verification and hydrogen concentration determination.

[0035] The interference spectrum of the hydrogen sensitive sensor 11 in the range of 0-3% of hydrogen gas volume fraction is shown in the attached figure. Figure 5 As shown, the optical signal is transmitted in the FP cavity 10 and produces interference. When the hydrogen concentration changes, the thickness and refractive index of the palladium metal hydrogen sensitive film 4 will change, thereby changing the position of the interference peak / valley in the transmission spectrum. The hydrogen concentration in the detection environment can be demodulated by detecting the movement of the interference peak / valley wavelength through the single peak tracking method. Figure 5 Obvious interference is observed, forming good, low-noise interference fringes. As hydrogen concentration increases, the reference interference trough blueshifts. Conversely, it redshifts. The FSR value measured by the double-peak tracking method is approximately 5.193nm. When the hydrogen concentration increases from 0% to 3%, the total blueshift of the reference trough is approximately 1.4885nm.

[0036] When the hydrogen concentration of hydrogen sensor 11 is 0-3.5% (step length 0.5%), the relationship between the wavelength drift of the nearest trough value (position 1548.600nm) of the FP interference center wavelength 1550nm and the hydrogen gas integral fraction is shown in the attached figure. Figure 6 As shown, according to the linear fitting results, the sensor exhibits a sensitivity of approximately 0.554 nm / % at low hydrogen concentrations, demonstrating good linearity. Simultaneously calibrated with a portable combustible gas concentration detector (20) and recorded with a stopwatch, the response time (T90) from hydrogen injection to spectral stabilization was ≤185 seconds at a hydrogen concentration close to 4%. Finally, a long-term stability test was conducted, continuously monitoring a 2% hydrogen concentration for 2 hours. The spectrometer (16) showed a stable spectral baseline with no significant drift (drift ≤0.05 nm), verifying the excellent stability and anti-interference properties of the hydrogen-sensitive sensor (11).

[0037] Components not described in detail herein are prior art.

[0038] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A hydrogen-sensitive sensor based on a coaxial, side-mounted, parallel optical fiber FP cavity, characterized by: It comprises an insert (1) and a sleeve (2), wherein the sleeve (2) is a shell with two transparent ends, and the insert (1) is provided at both ends of the sleeve (2), and two groups of the insert (1) and the sleeve (2) enclose an FP cavity (10); A group of the ferrules (1) is located at the left end of the sleeve (2), and a single-mode optical fiber (5) is provided between the ferrule and the sleeve (2), and the right end of the single-mode optical fiber (5) is connected to the FP cavity (10); Another group of the ferrules (1) is located at the right end of the sleeve (2), and a quartz capillary (7) is provided between the ferrule and the sleeve (2), a hydrogen diffusion hole (8) is provided on the quartz capillary (7), and a sealing material (9) is provided at the end of the quartz capillary (7) facing the FP cavity (10); A palladium metal hydrogen sensitive film (4) is provided at the opposite ends of the ferrule (1) and the FP cavity (10) at the right end; and sealing materials (6) are provided between the ferrule (1) and the single-mode optical fiber (5), the sleeve (2) and the quartz capillary (7).

2. A hydrogen-sensitive sensor based on coaxial, opposite, and side-mounted parallel optical fiber FP cavities according to claim 1, characterized in that: The sealing material (6) and the plugging material (9) are both made of CER500 epoxy resin.

3. The hydrogen-sensitive sensor based on coaxial, side-mounted parallel optical fiber FP cavity according to claim 1, characterized in that: A chromium metal film (3) is further provided between the insert (1) and the palladium metal hydrogen sensitive film (4).

4. A hydrogen-sensitive sensor based on coaxial, opposite, and side-mounted parallel optical fiber FP cavities according to claim 3, characterized in that: The hydrogen diffusion hole (8) is an isosceles triangle, is provided on the facing surfaces of the quartz capillary (7) and the insert (1), and corresponds to the positions of the palladium metal hydrogen sensitive film (4) and the chromium metal film (3).

5. The hydrogen-sensitive sensor based on coaxial, opposite, and side-mounted parallel optical fiber FP cavity according to claim 1, characterized in that: The right end of the single-mode optical fiber (5) is cut into a flat end face using an optical fiber cutter, and the inclination angle of the end face is less than 1°. The right end of the single-mode optical fiber (5) is polished to form a reflector (51).

6. The hydrogen-sensitive sensor based on coaxial, opposite, and side-mounted parallel optical fiber FP cavities according to claim 1, characterized in that: The single-mode optical fiber (5) and the quartz capillary (7) are distributed in a mirror-image manner within the sleeve (2).

7. A spectrometer detection system, characterized in that: Comprising a test box (12) and the hydrogen-sensitive sensor (11) according to any one of claims 1 to 5, the hydrogen-sensitive sensor (11) is installed in the test box (12), and the pigtail (111) of the hydrogen-sensitive sensor (11) protrudes from the test box (12) through a fiber outlet hole (128); The pigtail (111) is connected to the second interface (132) of the three-port circulator (13) via the optical fiber flange connector (15), the first interface (131) of the three-port circulator (13) is connected to the laser source (14), the third interface (133) of the three-port circulator (13) is connected to the spectrometer (16), and the spectrometer (16) is connected to the computer (18) via the host computer (17); The top of the test box (12) is connected to a hydrogen injection syringe (126) via an air valve (125), and the output end of the hydrogen injection syringe (126) is located inside the test box (12). A fan (127) is also provided inside the test box (12); A vent hole (122) is provided on the side wall of the test box (12), and a hose (19) is provided in the vent hole (122). One end of the hose (19) is connected to the interior of the test box (12), and the other end is connected to the combustible gas concentration detector (20).

8. The spectrometer detection system according to claim 7, characterized in that: The test box (12) comprises a base (121) and a box cover (124); the base (121) is a shell with a transparent top surface; the top of the base (121) is connected to the box cover (124) via a buckle (123); and a sealing ring is provided between the box cover (124) and the base (121).

9. The spectrometer detection system according to claim 7, characterized in that: The three interfaces of the three-port circulator (13) are respectively connected to the laser source (14), the optical fiber flange connector (15) and the spectrometer (16) through single-mode optical fibers (5).

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