CN217033615U - System for detecting hydrogen concentration through cantilever beam film of optical fiber end face - Google Patents

Abstract

The utility model discloses a system for detecting hydrogen concentration through a cantilever beam film on the end face of an optical fiber, which comprises a broadband light source, a spectrometer, an optical fiber circulator, an optical fiber hydrogen sensor, a hydrogen generator, a nitrogen generator and a gas mixer, wherein the optical fiber hydrogen sensor comprises an optical fiber and a cantilever beam film with a planar structure, a cavity extending inwards is arranged on one end face of the optical fiber, and the cantilever beam film is arranged on the end face of the optical fiber with the cavity and is positioned in front of the cavity. The thickness of a cantilever beam film of the optical fiber hydrogen sensor adopted by the system is in a nanometer magnitude, so that the detection of the concentration of the hydrogen outside is more sensitive, and the cavity of the Fabry-Perot interferometer is less influenced by the outside illumination, temperature and the like.

Description

System for detecting hydrogen concentration through cantilever beam film of optical fiber end face

Technical Field

The utility model relates to a hydrogen concentration detection technology, in particular to a system for detecting hydrogen concentration through a cantilever beam film on an optical fiber end face.

Background

Hydrogen is a clean energy source, and the combustion product in the air is only water, which can alleviate the global warming problem associated with fossil fuel consumption, and in addition, hydrogen has been widely used in the medical and biological fields as an antioxidant gas for preventing cancer or treating inflammation. However, when the volume concentration of hydrogen reaches the explosion limit of 4%, hydrogen has extremely high explosiveness in air, resulting in safety problems during transportation, storage and use. Therefore, the development of a fast, sensitive hydrogen sensor is of great importance in many energy, medical and biological applications.

Resistance-based hydrogen sensors, including electrochemical and microelectromechanical, while mature in manufacturing process and cost-controllable and low, still use electrical signals for demodulation, and thus present a potential risk of explosion triggered by electrical sparks during electrical signal readout. The optical fiber hydrogen sensor is widely researched due to the fact that the optical fiber hydrogen sensor can effectively avoid electromagnetic interference.

At present, the optical fiber hydrogen sensor is mainly divided into an evanescent field type and an optical fiber grating type, but the two types of optical fiber hydrogen sensors have small application prospects, because the evanescent field type can expose a fiber core, the strength of a sensing head is weakened, the mechanical performance and the stability of the hydrogen sensor are further influenced, and the optical fiber grating type is easily interfered by external temperature.

The optical fiber sensor based on the combination of the Fabry-Perot interferometer, the sensitive material palladium and the cantilever beam has the advantages of simple manufacture and low cost, realizes hydrogen measurement through cavity length change caused by stress, has extremely high response speed and sensitivity because one end of the cantilever beam is fixed and the other section is of a free end structure and is extremely sensitive to the change of physical quantities such as stress, temperature, mass and the like applied to the surface of the cantilever beam, and is widely researched in recent years.

Chinese patent No. CN201911294643.0 discloses an optical fiber end surface micro-cantilever sensor and a method for manufacturing the same. The fiber-optic end-face micro-cantilever sensor comprises: an optical fiber including a core and a cladding; the cantilever beam structure is polymerized on one end face of the optical fiber through a femtosecond laser two-photon polymerization technology; the cantilever beam structure is a polymer structure and comprises a support and a micro-cantilever beam; the first ends of the legs are coupled to the cladding of the fiber end face; one end of the micro cantilever beam is fixed at the second end of the pillar, and the other end of the micro cantilever beam is suspended above the fiber core to form a cantilever; the micro-cantilever is parallel to the end face of the optical fiber; the projection of the cantilever onto the fiber end face covers the core in a direction perpendicular to the fiber end face. When the optical fiber end surface micro-cantilever sensor is a hydrogen sensor, the surface of the micro-cantilever has a hydrogen sensitive film layer palladium film.

The preparation method of the optical fiber end surface micro-cantilever sensor comprises the following steps: step S1, cutting one end of the optical fiber, flatly placing and fixing the optical fiber on a glass slide, arranging a support part on the glass slide at two sides of the optical fiber to prevent the cover glass from extruding the optical fiber, dripping photoresist on the end face of the optical fiber, immersing the end face of the optical fiber in the photoresist, and covering the cover glass; s2, forming a polymer cantilever beam structure on the end face of the optical fiber by using a 3D photoetching machine and adopting a femtosecond laser two-photon polymerization technology to obtain an optical fiber sample with the cantilever beam structure; step S3, development: taking down the cover glass after curing, immersing the sample with the glass slide in a developing solution, dissolving unexposed photoresist in the solution, and reserving the cured polymer cantilever beam structure; and step S4, plating a hydrogen sensitive film layer palladium film on the surface of the micro cantilever by using a magnetron sputtering coating instrument.

The cantilever structure in the above patent is a three-dimensional structure composed of a pillar and a micro-cantilever, and the pillar plays a supporting role, so that an air gap is formed between the cantilever on the micro-cantilever and the fiber core of the optical fiber, and the air gap is a cavity of the fabry-perot interferometer. The cantilever beam structure of the three-dimensional structure is large in overall thickness, can only achieve a micron level, is not compact enough in structure, influences the sensitivity of hydrogen concentration detection, and meanwhile, the cavity of the Fabry-Perot interferometer is completely arranged outside the fiber core, so that the measurement accuracy is easily influenced by external illumination, temperature and the like.

SUMMERY OF THE UTILITY MODEL

In order to solve the defects of the prior art, the utility model provides a system, the hydrogen concentration is detected through a cantilever beam film on the end face of an optical fiber, the thickness of the cantilever beam film is small, and the cavity of the Fabry-Perot interferometer is less influenced by external illumination, temperature and the like.

The technical problem to be solved by the utility model is realized by the following technical scheme:

a system for detecting hydrogen concentration through a cantilever beam film on the end face of an optical fiber comprises a broadband light source, a spectrometer, an optical fiber circulator, an optical fiber hydrogen sensor, a hydrogen generator, a nitrogen generator and a gas mixer, wherein the optical fiber hydrogen sensor comprises an optical fiber and a cantilever beam film with a planar structure, a cavity extending inwards is formed in one end face of the optical fiber, and the cantilever beam film is arranged on the end face, provided with the cavity, of the optical fiber and is positioned in front of the cavity;

the optical fiber circulator is provided with an incident end, a reflecting end and a transmitting end, the incident end is connected with the broadband light source, the reflecting end is connected with the spectrometer, and the transmitting end is connected with one end of the optical fiber hydrogen sensor, which is not provided with the cantilever beam film; the gas mixer is provided with a first gas inlet end, a second gas inlet end and a gas outlet end, the hydrogen generator is communicated with the first gas inlet end, the nitrogen generator is communicated with the second gas inlet end, and one end, provided with the cantilever beam film, of the optical fiber hydrogen sensor is arranged in the gas outlet end.

Further, the optical fiber comprises a core and a cladding, and the cavity is at least located on an end face of the core.

Further, the cantilever beam film comprises a film periphery and a film cantilever which are positioned on the same plane, the film periphery is fixed on a cladding of the end face of the optical fiber and is provided with a hollow-out area corresponding to the cavity; the film cantilever is positioned in the hollow area at the periphery of the film, one end of the film cantilever is fixed with the periphery of the film, and the other end of the film cantilever is suspended in front of the cavity and corresponds to the fiber core on the end face of the optical fiber.

Further, the projection of the film cantilever on the fiber end surface is located in the cavity and covers the fiber core of the fiber end surface.

Further, the cantilever beam film comprises a suspended film layer arranged on the end face of the optical fiber, a supporting film layer arranged on the suspended film layer and a hydrogen sensitive film layer arranged on the supporting film layer.

Further, the suspension film layer is a graphene film, the support film layer is a gold film, and the hydrogen sensitive film layer is a palladium film.

Further, the chamber is a hemispherical cavity.

Further, still include hydrogen flow valve and nitrogen gas flow valve, the hydrogen generator passes through the hydrogen flow valve with the first inlet end of gas mixer is linked together, the nitrogen generator passes through the nitrogen flow valve with the second inlet end of gas mixer is linked together.

Further, still include the host computer, the host computer respectively with hydrogen flow valve and nitrogen gas flow valve communication are connected.

Further, the gas mixer is a T-shaped three-way plastic pipe.

The utility model has the following beneficial effects: the optical fiber hydrogen sensor adopted by the system arranges a cavity of a Fabry-Perot interferometer in the optical fiber, and then the cantilever beam film is manufactured on the end face of the optical fiber, compared with the prior art that the cavity is external and adopts a cantilever beam structure with a three-dimensional structure, the cavity is arranged in the optical fiber, so that the influence of external illumination, temperature and the like on measurement precision can be reduced, meanwhile, the cantilever beam film is of a planar structure, has small overall thickness and can reach a nano level, the structure is more compact, and the nano level film is more sensitive to external hydrogen concentration detection.

Drawings

FIG. 1 is a schematic cross-sectional view of an optical fiber hydrogen sensor for detecting hydrogen concentration via a cantilever beam film on an end face of an optical fiber according to the present invention;

FIG. 2 is a schematic end view of an optical fiber hydrogen sensor for detecting hydrogen concentration by a cantilever beam film on the end surface of an optical fiber according to the present invention;

FIG. 3 is a schematic diagram of a system for detecting hydrogen concentration via a cantilever membrane at the end face of an optical fiber according to the present invention;

FIG. 4 is a reflection spectrum of the system for detecting hydrogen concentration via a cantilever beam film on the end face of an optical fiber shown in FIG. 3;

FIG. 5 is a block diagram of the steps of a method for manufacturing an optical fiber hydrogen sensor according to the present invention;

fig. 6 is a block diagram illustrating a step S1 of the method for manufacturing the optical fiber hydrogen sensor shown in fig. 5;

fig. 7 is a block diagram of another step S1 in the method for manufacturing the optical fiber hydrogen sensor shown in fig. 5;

fig. 8 is a block diagram of another step S2 in the method for manufacturing the optical fiber hydrogen sensor shown in fig. 5.

Detailed Description

The utility model is described in detail below with reference to the drawings, wherein examples of the embodiments are shown in the drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below with reference to the accompanying drawings are illustrative and intended to explain the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second", "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," "disposed," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the interconnection of two elements or through the interaction of two elements. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

Example one

As shown in fig. 1 and 2, an optical fiber hydrogen sensor 1 for detecting hydrogen concentration by a cantilever beam film on an end face of an optical fiber, includes:

an optical fiber 11 having a cavity 113 extending inward on one end face;

and a cantilever film 12 of a planar structure, disposed on the end face of the optical fiber 11 having the cavity 113, and located in front of the cavity 113.

This optic fibre hydrogen sensor 1 will fabry-perot interferometer's cavity 113 is arranged in optic fibre 11, then make on the terminal surface of optic fibre 11 cantilever beam film 12, compare with the external cantilever beam structure's of cavity 113 prior art who adopts spatial structure, will place in cavity 113 in optic fibre 11 can alleviate the influence of external illumination, temperature etc. to measurement accuracy, simultaneously, cantilever beam film 12 is planar structure, and the total thickness is little, can reach nanometer level not only the structure compacter, and nanometer level film is more sensitive to external hydrogen concentration detection.

The chamber 113 is an open chamber and communicates with the outside at the end face of the optical fiber 11. The optical fiber 11 includes a core 111 and a cladding 112, the cavity 113 is at least located on an end surface of the core 111, and depending on the size of the cavity 113, the cavity 113 may also be located on an end surface of the cladding 112; in this embodiment, the cavity 113 is located on both end surfaces of the core 111 and the cladding 112, the core 111 corresponds to the center of the cavity 113, the cladding 112 corresponds to the periphery of the cavity 113, and the range of the cavity 113 does not exceed the cladding 112.

The cantilever beam film 12 comprises a film periphery 121 and a film cantilever 122 which are positioned on the same plane, wherein the film periphery 121 is fixed on the cladding 112 of the end face of the optical fiber 11 and is provided with a hollow-out area corresponding to the cavity 113; the film cantilever 122 is located in the hollow area of the film periphery 121, one end of the film cantilever is fixed to the film periphery 121, and the other end of the film cantilever is suspended in front of the cavity 113 and corresponds to the fiber core 111 on the end face of the optical fiber 11.

The thin film periphery 121 plays a supporting role in this case, so as to support one end of the thin film cantilever 122, so that the other end of the thin film cantilever 122 can suspend in front of the cavity 113 and corresponds to the fiber core 111 on the end face of the optical fiber 11; the projection of the thin film cantilever 122 on the end face of the optical fiber 11 is located in the cavity 113 and covers the core 111 of the end face of the optical fiber 11.

The chamber 113 is not closed by the thin film cantilever 122, but communicates with the outside through a gap between the thin film cantilever 122 and the thin film periphery 121.

The cantilever beam film 12 comprises a suspended film layer arranged on the end face of the optical fiber 11, a supporting film layer arranged on the suspended film layer and a hydrogen sensitive film layer arranged on the supporting film layer.

In this embodiment, the suspension thin film layer is a graphene thin film, the support thin film layer is a gold thin film, and the hydrogen sensitive thin film layer is a palladium thin film.

In this embodiment, the chamber 113 is a hemispherical chamber.

Example two

FIG. 3 shows a system for detecting hydrogen concentration by a cantilever beam film on the end face of an optical fiber, comprising:

the fiber optic hydrogen sensor 1 of embodiment one; and

a broadband light source 2, a spectrometer 3, a fiber circulator 4, a hydrogen gas generator 6, a hydrogen flow valve 7, a nitrogen gas generator 8, a nitrogen flow valve 9 and a gas mixer 5,

the optical fiber circulator 4 is provided with an incident end, a reflecting end and a transmitting end, wherein the incident end is connected with the broadband light source 2, the reflecting end is connected with the spectrometer 3, and the transmitting end is connected with one end of the optical fiber hydrogen sensor 1 without the cantilever beam film 12; gas mixer 5 has first inlet end, second inlet end and gives vent to anger the end, hydrogen generator 6 passes through hydrogen flow valve 7 with first inlet end is linked together, nitrogen generator 8 passes through nitrogen flow valve 9 with the second inlet end is linked together, optic fibre hydrogen sensor 1 has the one end of cantilever beam film 12 is arranged in give vent to anger in the end.

The system further comprises an upper computer, wherein the upper computer is respectively in communication connection with the hydrogen flow valve 7 and the nitrogen flow valve 9 so as to respectively control the hydrogen flow valve 7 and the nitrogen flow valve 9, and the hydrogen concentration ratio is realized by controlling the flow of hydrogen and nitrogen.

The upper computer can be but not limited to a PC, an industrial personal computer or an intelligent terminal and the like.

In this embodiment, the gas mixer 5 is a T-shaped three-way plastic pipe with an inner diameter of about 5 mm.

The test principle of the system is as follows:

when a cantilever beam film 12 consisting of a suspension film layer, a support film layer and a hydrogen sensitive film layer is suspended in front of the cavity 113 on the end face of the optical fiber 11, the cantilever beam film and the optical fiber 11-air interface form a Fabry-Perot cavity; the broadband light source 2 emits detection light with a broadband spectrum into the incident end of the optical fiber circulator 4, the detection light enters the optical fiber hydrogen sensor 1 from the transmission end through the optical fiber circulator 4, is processed by the fabry-perot cavity, returns to the optical fiber circulator 4, and enters the spectrometer 3 from the reflection end, so as to obtain a reflection spectrum of the fabry-perot interferometer shown in fig. 4; when the hydrogen sensitive thin film layer on the cantilever beam thin film 12 absorbs hydrogen, the shape of the hydrogen sensitive thin film layer changes, and then the thin film cantilever 122 on the cantilever beam thin film 12 is driven to swing, so that the cavity length of the fabry-perot cavity is correspondingly changed, the change of the cavity length is reflected as the movement of the resonant wavelength in the reflection spectrum received by the spectrometer 3, and the hydrogen sensitivity of the optical fiber hydrogen sensor 1 can be obtained by fitting the relation between the resonant wavelength movement and the hydrogen concentration.

EXAMPLE III

A method for preparing an optical fiber hydrogen sensor, which is used for preparing the optical fiber hydrogen sensor 1 in the first embodiment.

As shown in fig. 5, the preparation method comprises the following steps:

s1: as shown in fig. 1 and 2, a cavity 113 is formed on an end face of the optical fiber 11 to extend inward.

In step S1, the cavity 113 is an open cavity and communicates with the outside at the end face of the optical fiber 11. The optical fiber 11 includes a core 111 and a cladding 112, the cavity 113 is at least located on an end surface of the core 111, and depending on the size of the cavity 113, the cavity 113 may also be located on an end surface of the cladding 112; in this embodiment, the cavity 113 is located on both end surfaces of the core 111 and the cladding 112, the core 111 corresponds to the center of the cavity 113, the cladding 112 corresponds to the periphery of the cavity 113, and the range of the cavity 113 does not exceed the cladding 112.

In this embodiment, the chamber 113 is a hemispherical chamber.

In one embodiment, as shown in FIG. 6, the step of forming an inwardly extending cavity 113 in an end face of the optical fiber 11 is as follows:

s1.1: one end face of each of the two optical fibers 11 is cut flat.

In this step S1.1, but not limited to, one end face of one of the optical fibers 11 may be cut flat by using an optical fiber 11 cutter, and then one end face of the other optical fiber 11 may be cut flat.

S1.2: the end faces of the two optical fibers 11 that have been cut flat are heated to an arc shape.

In step S1.2, the cut flat end surfaces of the two optical fibers 11 may be placed at two ends of the optical fiber 11 fusion splicer, the cut flat end surfaces of the two optical fibers 11 may be displaced to the outer edge of the heating center (the end surfaces of the two optical fibers 11 are not in contact) by the driving of the motor in the optical fiber 11 fusion splicer, and then the cut flat end surfaces of the two optical fibers 11 may be heated to an arc shape (the two optical fibers 11 are not fused) by adjusting the discharge parameters.

S1.3: the end faces of the two optical fibers 11 in the shape of a circular arc are coated with a refractive index matching fluid.

In this step S1.3, the index matching fluid eliminates reflection losses associated with the fiber 11-air interface.

S1.4: the end faces of the two optical fibers 11 coated with the refractive index matching fluid are heat-fused, and the refractive index matching fluid is vaporized to form a bubble chamber at the fusion-spliced portion of the two optical fibers 11.

In step S1.4, the end surfaces of the two optical fibers 11 coated with the refractive index matching fluid may be placed at two ends of the optical fiber 11 fusion splicer, the end surfaces of the two optical fibers 11 coated with the refractive index matching fluid may be moved to a heating center (the end surfaces of the two optical fibers 11 are in contact) by driving a motor in the optical fiber 11 fusion splicer, and then the end surfaces of the two optical fibers 11 coated with the refractive index matching fluid may be heated and fused by adjusting discharge parameters; during the fusion splicing process, the refractive index matching fluid is heated and vaporized, so that a bubble chamber is formed at the fusion splice of the two optical fibers 11.

In this embodiment, the bubble chamber is a closed chamber and is a spherical chamber.

S1.5: the two fusion-spliced optical fibers 11 are cut from the middle of the bubble chamber, and two optical fibers 11 having the cavity 113 on one end surface are obtained.

In step S1.5, the two optical fibers 11 that have been welded may be placed on a two-dimensional displacement platform and fixed, and then under the monitoring of the CCD and the display, the two-dimensional displacement platform is controlled to move, so as to position the bubble cavity at the welding position of the two optical fibers 11 below the optical fiber 11 cutting knife, and then the optical fiber 11 cutting knife is controlled to cut off the two optical fibers 11 that have been welded from the middle of the bubble cavity, so as to obtain two optical fibers 11 each having the cavity 113 on one end surface.

In another embodiment, as shown in FIG. 7, the step of forming an inwardly extending cavity 113 in an end face of the optical fiber 11 is as follows:

s1.1: an end face of one optical fiber 11 is cut flat.

In this step S1.1, an end face of the optical fiber 11 may be, but is not limited to, flattened by using a fiber 11 cutter.

S1.2: and etching a small hole on the flattened end face of the optical fiber 11 by using femtosecond laser.

In step S1.2, the optical fiber 11 is first placed on a three-axis displacement platform and fixed, then the three-dimensional displacement platform is controlled to move under the monitoring of the CCD and the display, the cut end surface of the optical fiber 11 is moved to the focal position of the femtosecond laser, then the output power of the femtosecond laser is adjusted appropriately, and the emitted femtosecond laser spot is focused on the fiber core 111 at the end surface of the optical fiber 11, so as to etch the small hole on the fiber core 111 at the end surface of the optical fiber 11.

S1.3: and heating and welding the end face of the optical fiber 11 with the small hole with the cut end face of the other optical fiber 11, and simultaneously expanding the gas in the small hole by heating so that the small hole is expanded at the welding position of the two optical fibers 11 to form a bubble cavity.

An end face of the other optical fiber 11 may also be flattened by a fiber 11 cutter, which may be performed in any step prior to step S1.3, preferably in step S1.1 by flattening an end face of each of the two optical fibers 11.

In this step S1.3, one optical fiber 11 having the small hole at one end and another optical fiber 11 having a flattened end are placed in an optical fiber 11 fusion splicer, the end face having the small hole and the flattened end face of the two optical fibers 11 are displaced into a heating center (the end faces of the two optical fibers 11 are in contact) by the driving of a motor in the optical fiber 11 fusion splicer, and then the end face having the small hole and the flattened end face of the two optical fibers 11 are heat-fused by adjusting discharge parameters; during fusion splicing, the gas in the small hole is thermally expanded, so that the small hole is expanded to form a bubble chamber at the fusion splice of the two optical fibers 11.

During fusion, the expansion degree of the gas in the small hole can be controlled by repeatedly discharging through the optical fiber 11 fusion splicer, and the size of the bubble cavity is further adjusted.

In this embodiment, the bubble chamber is a closed chamber and is a spherical chamber.

S1.4: the two fusion-spliced optical fibers 11 are cut from the middle of the bubble chamber, and two optical fibers 11 having the cavity 113 on one end surface are obtained.

In step S1.4, the two optical fibers 11 that have been welded may be placed on a two-dimensional displacement platform and fixed, and then under the monitoring of the CCD and the display, the two-dimensional displacement platform is controlled to move, so as to position the bubble cavity at the welding position of the two optical fibers 11 below the optical fiber 11 cutting knife, and then the optical fiber 11 cutting knife is controlled to cut off the two optical fibers 11 that have been welded from the middle of the bubble cavity, so as to obtain two optical fibers 11 each having the cavity 113 on one end surface.

S2: and manufacturing a cantilever beam film 12 with a plane structure on the end face of the optical fiber 11 with the cavity 113, wherein the cantilever beam film 12 is positioned in front of the cavity 113.

In this embodiment, the cantilever film 12 includes a suspended film layer disposed on the end face of the optical fiber 11, a supporting film layer disposed on the suspended film layer, and a hydrogen sensitive film layer disposed on the supporting film layer; as shown in fig. 8, the steps of fabricating the cantilever film 12 of a planar structure on the end face of the optical fiber 11 having the cavity 113 are as follows:

s2.1: a layer of suspended film is fabricated on the end face of the optical fiber 11 having the cavity 113.

In this step S2.1, the area of the floating film layer corresponding to the chamber 113 floats in front of the chamber 113, and the chamber 113 is sealed.

In this embodiment, the suspended thin film layer is a graphene thin film, and the thickness of the suspended thin film layer is about 2 nm; the steps of manufacturing a graphene film on the end face of the optical fiber 11 having the cavity 113 are as follows:

s2.1.1: and growing graphene on the copper foil by a chemical vapor deposition method to obtain the copper-based graphene.

S2.2.2: cutting a small piece in the copper-based graphene, placing the small piece in a FeCl3 solution, and waiting for the FeCl3 solution to completely corrode the copper-based graphene, thereby obtaining the graphene film.

In this step 2.2.2, the concentration of the FeCl3 solution is about 0.075 g/ml.

S2.2.3: and repeatedly filtering waste liquid in the FeCl3 solution by using deionized water to enable the graphene film to float on the deionized water.

S2.2.4: and contacting one end face, provided with the cavity 113, of the optical fiber 11 with the graphene film on the deionized water so as to transfer the graphene film on the deionized water to the end face of the optical fiber 11, and forming a suspended graphene film after water in the graphene film on the end face of the optical fiber 11 is evaporated.

In this step S2.2.4, the end face of the optical fiber 11 needs to be slowly moved to be close to the graphene film on the deionized water until the end face of the optical fiber 11 contacts the graphene film, and then the end face of the optical fiber 11 is pulled away from the liquid level; as the water is evaporated, the periphery of the graphene film is attached to and fixed to the cladding 112 on the end surface of the optical fiber 11 due to van der waals force, and the center of the graphene film is suspended in front of the cavity 113.

S2.2: and manufacturing a supporting thin film layer on the suspended thin film layer.

In step S2.1, the supporting thin film layer may be manufactured by a magnetron sputtering method, the optical fiber 11 is first fixed in a coating cavity of a magnetron sputtering coating instrument, so that the suspended thin film layer on the end surface of the optical fiber 11 faces a thin film target, and then the magnetron sputtering coating instrument is controlled to sputter the thin film target on the graphene film, so as to form the supporting thin film layer.

During sputtering, the suspended thin film layer plays a role in supporting the bottom of the supporting thin film layer to support the supporting thin film layer, so that the supporting thin film layer and the suspended thin film layer are suspended together, and the supporting thin film layer is prevented from being sputtered onto the bottom of the cavity 113.

In this embodiment, the supporting thin film layer is a gold thin film, and the thickness is about 200 nm.

S2.3: and etching the suspended film layer and the supporting film layer according to the plane structure of the cantilever beam film 12.

In step S2.3, the optical fiber 11 is placed on a three-axis displacement platform, and the three-dimensional displacement platform is controlled to move under the monitoring of the CCD and the display, to move the suspended thin film layer and the supporting thin film layer on the end face of the optical fiber 11 to the focus of the femtosecond laser, then adjusting the output power of the femtosecond laser, directly focusing the facula of the femtosecond laser on the suspended film layer and the supporting film layer on the end face of the optical fiber 11, then setting a motion track function of the femtosecond laser relative to the end face of the optical fiber 11 according to the suspended film layer and the supporting film layer, wherein the motion track of the femtosecond laser is precisely controlled by the three-axis displacement platform, and the triaxial displacement platform drives the end face of the optical fiber 11 to move relative to the femtosecond laser according to the movement track of the femtosecond laser, and finally, the plane structure of the cantilever beam film 12 is etched on the suspension film layer and the support film layer.

When the film is etched, the supporting film layer supports the suspended film layer, so that the suspended film layer is prevented from collapsing due to too thin film when being etched.

As shown in fig. 1 and 2, the cantilever film 12 includes a film periphery 121 and a film cantilever 122 located on the same plane, the film periphery 121 is fixed on the cladding 112 of the end face of the optical fiber 11, and has a hollow area corresponding to the cavity 113; the thin film cantilever 122 is located in the hollow area of the thin film periphery 121, one end of the thin film cantilever is fixed to the thin film periphery 121, and the other end of the thin film cantilever suspends in front of the cavity 113 and corresponds to the fiber core 111 on the end face of the optical fiber 11.

The thin film periphery 121 plays a supporting role in this case, so as to support one end of the thin film cantilever 122, so that the other end of the thin film cantilever 122 can suspend in front of the cavity 113 and corresponds to the fiber core 111 on the end face of the optical fiber 11; the projection of the thin film cantilever 122 on the end face of the optical fiber 11 is located in the cavity 113 and covers the core 111 of the end face of the optical fiber 11.

The chamber 113 is not closed by the membrane cantilever 122, but communicates with the outside through a gap between the membrane cantilever 122 and the membrane periphery 121.

S2.4: and manufacturing a hydrogen sensitive film layer on the support film layer.

In step S2.4, the hydrogen-sensitive thin film layer may be manufactured by a magnetron sputtering method, the optical fiber 11 is first fixed in a coating cavity of a magnetron sputtering coating instrument, so that the support thin film layer on the end surface of the optical fiber 11 faces the hydrogen-sensitive target, and then the magnetron sputtering coating instrument is controlled to sputter the hydrogen-sensitive target on the support thin film layer to form the hydrogen-sensitive thin film layer.

In this embodiment, the hydrogen sensitive thin film layer is a palladium thin film.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the embodiments of the present invention and not for limiting the same, and although the embodiments of the present invention are described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot make the modified technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A system for detecting hydrogen concentration through a cantilever beam film on the end face of an optical fiber comprises a broadband light source, a spectrometer, an optical fiber circulator, an optical fiber hydrogen sensor, a hydrogen generator, a nitrogen generator and a gas mixer, and is characterized in that the optical fiber hydrogen sensor comprises an optical fiber and a cantilever beam film with a planar structure, a cavity extending inwards is arranged on one end face of the optical fiber, and the cantilever beam film is arranged on the end face of the optical fiber with the cavity and is positioned in front of the cavity;

the optical fiber circulator is provided with an incident end, a reflecting end and a transmitting end, the incident end is connected with the broadband light source, the reflecting end is connected with the spectrometer, and the transmitting end is connected with one end of the optical fiber hydrogen sensor, which is not provided with the cantilever beam film; the gas mixer is provided with a first gas inlet end, a second gas inlet end and a gas outlet end, the hydrogen generator is communicated with the first gas inlet end, the nitrogen generator is communicated with the second gas inlet end, and one end, provided with the cantilever beam film, of the optical fiber hydrogen sensor is arranged in the gas outlet end.

2. The system for detecting hydrogen concentration according to claim 1, wherein the optical fiber comprises a core and a cladding, and the chamber is located at least on the end face of the core.

3. The system for detecting hydrogen concentration by using a cantilever beam film on an optical fiber end face as claimed in claim 2, wherein the cantilever beam film comprises a film periphery and a film cantilever, which are located on the same plane, the film periphery is fixed on a cladding of the optical fiber end face and is provided with a hollow-out area corresponding to the chamber; the film cantilever is positioned in the hollow area at the periphery of the film, one end of the film cantilever is fixed with the periphery of the film, and the other end of the film cantilever is suspended in front of the cavity and corresponds to the fiber core of the end face of the optical fiber.

4. The system according to claim 3, wherein the projection of the membrane cantilever onto the fiber end face is located in the chamber and covers the core of the fiber end face.

5. The system for detecting hydrogen concentration through a cantilever beam film of an optical fiber end face according to claim 1, wherein the cantilever beam film comprises a suspended thin film layer disposed on the optical fiber end face, a supporting thin film layer disposed on the suspended thin film layer, and a hydrogen sensitive thin film layer disposed on the supporting thin film layer.

6. The system for detecting hydrogen concentration by means of a cantilever beam film on an end face of an optical fiber according to claim 5, wherein the suspended thin film layer is a graphene film, the supporting thin film layer is a gold film, and the hydrogen-sensitive thin film layer is a palladium film.

7. The system for detecting hydrogen concentration via cantilever beam film of optical fiber end face of claim 1, wherein the chamber is a hemispherical chamber.

8. The system for detecting hydrogen concentration through cantilever beam thin film of optical fiber end face of claim 1, further comprising a hydrogen flow valve through which said hydrogen generator communicates with said first gas inlet end of said gas mixer and a nitrogen flow valve through which said nitrogen generator communicates with said second gas inlet end of said gas mixer.

9. The system for detecting hydrogen concentration through a cantilever beam film on an optical fiber end face according to claim 8, further comprising an upper computer, wherein the upper computer is in communication connection with the hydrogen flow valve and the nitrogen flow valve respectively.

10. The system for detecting hydrogen concentration via cantilever beam membrane of optical fiber end face of claim 1, wherein the gas mixer is a T-tee plastic tube.

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