CN108801941A - Gas identification fibre optical sensor based on metal-organic framework material and recognition methods - Google Patents
Gas identification fibre optical sensor based on metal-organic framework material and recognition methods Download PDFInfo
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- CN108801941A CN108801941A CN201811008578.6A CN201811008578A CN108801941A CN 108801941 A CN108801941 A CN 108801941A CN 201811008578 A CN201811008578 A CN 201811008578A CN 108801941 A CN108801941 A CN 108801941A
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Abstract
The present invention discloses a kind of gas identification fibre optical sensor and recognition methods based on metal-organic framework material, and the coupling that sandwich layer mould arrives cladding mode, the transmission respectively of realization sandwich layer mould and cladding mode occur at the first long-period fiber grating；Cascaded optical fiber sensitive layer adsorbs known gas so that cladding mode refraction index changing；In second long-period gratings, the optical coupling of cladding mode returns to sandwich layer to interfere, and obtains interference spectrum；According to the correspondence between interference spectrum and gas with various, recognition detection gas；It is sensitive to have the advantages that fast response time identifies.
Description
Technical field
The invention belongs to sensory field of optic fibre, more particularly to a kind of fiber optic sensor technology.
Background technology
In recent years, with industrial or agricultural modernize expanding economy, timely and accurately to inflammable, explosive, poisonous pernicious gas into
Row monitoring and prediction and control, it has also become departments' major issue anxious to be resolved such as current coal, oil, chemical industry, electric power.Meanwhile
As the improvement of people's living standards, the requirement that the mankind purify ecological environment is also higher and higher, an urgent demand monitoring is easy
Explosive and toxic and harmful gas is fired, is reduced environmental pollution, it is ensured that is physically and mentally healthy.Therefore it is very to develop gas recognition detection system
Important, since gas to be detected is generally in the hazardous environments such as high temperature, high pressure, corrosion, limit the use of electric sensor.
And non-optical sensor is easily influenced by the factors such as sensitive and sensing membrane surface contamination are intersected, and low-response, short life can weigh
Renaturation is poor, it is difficult to which real-time online continuously monitors.
Optical fiber has small, bandwidth, transmission loss is low, electromagnetism interference is strong and carrying contain much information etc. it is special
Point has electromagnetism interference by the sensor that it is constituted, electrical isolation, corrosion-resistant, high sensitivity, is convenient for multiplexing, convenient for networking etc.
Plurality of advantages.The technology utilize the light propagated in optical fiber caused by external physical quantity characterisitic parameter (such as intensity, phase, wavelength,
Polarization, scattering etc.) variation, external physical quantity is measured and data transmission.It is dry with small, light-weight, anti-electromagnetism
It disturbs, safe (no electric spark can work under inflammable, explosive environments), test side is without power supply, high temperature resistant, and is convenient for
The advantages that forming sensor network, fusion Internet of Things.Therefore fiber parametric amplification as a kind of novel sensing detection device by
The attention of researcher, and widely studied and apply.And one layer of sensitive metal organic framework materials will be coated on optical fiber
Device be will further improve to the detection response speed of gas and sensitivity.
Metal-organic framework material, abbreviation MOFs is a series of with various structures, the material of multifunction.It is wide
General to be applied to structural chemistry, this material has potential using value in very more fields, as gas storage, gas separation,
Heterocatalysis, chemical sensitisation, nonlinear optics, energy stores and conversion (battery and solar cell), drug delivery, biology at
As etc..
But existing sensor there is also：Fiber-optic fiber gas recognition detection device response speed, sensitivity etc. all
The problems such as there is corresponding deficiencies.
Invention content
In order to solve the above technical problem, the present invention provides a kind of, and the gas based on metal-organic framework material identifies optical fiber
Sensor and recognition methods have very fast in conjunction with the fiber-optic fiber gas recognition detection device that sensitive layer is metal-organic framework material
Response speed and very high sensitivity.
The technical solution adopted by the present invention is：A kind of Mach of increasing Dare interferometer, includes at least：First long period optical fiber light
Grid, the second long-period fiber grating；It connects between first long-period fiber grating and the second long-period fiber grating level-one
Join optical fiber；The sandwich layer of the cascaded optical fiber and covering grow one respectively as the two-arm of interferometer on the cascaded optical fiber covering
Layer sensitive layer.
Further, the sensitive layer is the metal-organic framework material of one layer of porous ZIF-8.
A kind of gas identification fibre optical sensor based on metal-organic framework material, it is dry to include at least above-mentioned Mach increasing Dare
Interferometer.
The present invention also provides a kind of organic gas detection methods, include the following steps：
Coupling of the sandwich layer mould to cladding mode occur at the first long-period gratings for the sandwich layer light in optical fiber, formed sandwich layer mould and
The transmission respectively of cladding mode；
Cascaded optical fiber sensitive layer adsorbs organic gas to be detected so that cladding mode refraction index changing；
In second long-period gratings, the optical coupling of cladding mode returns to sandwich layer to interfere, and obtains interference spectrum；
According to the correspondence between interference spectrum and gas with various, organic gas to be detected is identified.
Further, the correspondence between the interference spectrum and gas with various establishes process and is：
Coupling of the sandwich layer mould to cladding mode occur at the first long-period gratings for the sandwich layer light in optical fiber, formed sandwich layer mould and
The transmission respectively of cladding mode；
Cascaded optical fiber sensitive layer adsorbs known gas so that cladding mode refraction index changing；
In second long-period gratings, the optical coupling of cladding mode returns to sandwich layer to interfere, and obtains interference spectrum；
The correspondence between the known gas is established according to several interference spectrums.
Beneficial effects of the present invention：Sandwich layer mould occurs at the first long-period fiber grating and arrives for the light that light source of the present invention is sent out
The transmission respectively of sandwich layer mould and cladding mode is realized in the coupling of cladding mode；Cascaded optical fiber sensitive layer adsorbs known gas so that covering
Modal refractive index changes；In second long-period gratings, the optical coupling of cladding mode returns to sandwich layer to interfere, and is interfered
Spectrum；According to the correspondence between interference spectrum and gas with various, recognition detection gas；The system and method for the present invention uses
Cascade-connection long period fiber grating combination sensitive layer is the fiber-optic fiber gas recognition detection device of metal-organic framework material to specific gas
Body has response speed and very high sensitivity quickly, can be applied to environmental monitoring and chemical sensitisation etc.；And using this
Sensor more minimizes made of the structure of invention, cost performance also higher.
Description of the drawings
Fig. 1 is the basic block diagram of the cascade-connection long period fiber grating of coating metal-organic framework material in the present invention.
Transmission spectrum figures of the Fig. 2 by device different moments in the case where surveying atmosphere；
Wherein, Fig. 2 (a) is the spectrogram tested ethyl alcohol and obtained, and Fig. 2 (b) is the spectrogram tested methanol and obtained, Fig. 2 (c)
For the spectrogram that test ethyl acetate obtains, Fig. 2 (d) is the spectrogram tested acetone and obtained, and Fig. 2 (e) is test dichloromethane
Obtained spectrogram, Fig. 2 (f) are the spectrogram tested pyridine and obtained, and Fig. 2 (g) is the spectrogram tested ether and obtained, Fig. 2 (h)
For the spectrogram that test toluene obtains, Fig. 2 (i) is the spectrogram tested hexamethylene and obtained.
Specific implementation mode
For ease of those skilled in the art understand that the present invention technology contents, below in conjunction with the accompanying drawings to the content of present invention into one
Step is illustrated.
In various MOFs, ZIF-8 is a kind of porous frame being polymerized by zinc nitrate hexahydrate and 2- methyl-imidazoles
Frame material, aperture sizeSpecific surface area is up to 1947m2g-1, and chemical stability and thermal stability are very good, thermal decomposition
Temperature has potential using value at 450 DEG C or more, in gas identification with sensory field.Therefore, porous material ZIF-8 is combined
The long-period fiber grating film gas identification detector to get up there is extremely excellent performance, it can be achieved that remote telemetering and
Line monitors in real time, and the high miniaturized device of the ratio of performance to price can be made.
It is as shown in Figure 1 the basic sensing knot of the cascade-connection long period fiber grating of coating metal-organic framework material ZIF-8
Composition.Optical fiber, which is immersed in the methanol solution of zinc nitrate hexahydrate and 2- methyl-imidazoles, can be grown on ZIF-8 optical fiber packet
On layer, Figure 1B and C are optical fiber surface and the scanning electron microscope (SEM) photograph of end face respectively.
A kind of Volatile Organic Compounds Recognition fibre optical sensor based on metal-organic framework material of the present invention, individually by two sections
The one of the cascaded optical fiber that one segment length of series connection is d (this length can arbitrarily change) among long-period fiber grating (LPG1 and LPG2)
The special long-period fiber grating combination of kind.When the structure parameter of this two sections individual long-period fiber grating LPG1 and LPG2 is identical
When, after LPG1, core mode part is coupled to cladding mode for light that light source is sent out, cladding mode and remaining core mode edge respectively
Covering and fibre core transmission, at LPG2, cladding mode is coupled back into fibre core again becomes core mode, and the fibre not coupled with process LPG1
Core model interferes.It is similar with Mach-Zehnder interferometers that light transmits its operation principle in LPG1 and LPG2.And it is intermediate long
The fiber section that degree is d coats the metal-organic framework material of one layer of ZIF-8 as gas sensitive, using the material to not of the same race
The different adsorption strengths and adsorbance of class gas, to which the transmission for changing the effective refractive index of sensitive layer and then change cladding mode is normal
Number, to change the characteristic of output spectrum.
If identical with the two-beam wave phase of covering from sandwich layer, the interference of light of output end is mutually grown；If two-beam wave phase
Position phase difference of pi, then output end interfere cancellation.Covering Effective index hairs of the gas sensitive ZIF-8 after having adsorbed gas with various
Raw different amounts of change, just has the variation of wavelength and intensity, it is possible thereby to establish gas with various in the interference spectrum of output end
Correspondence between interference spectrum, to realize that gas identifies.
The same below specific operation principle illustrates：
Sensor is worked using wideband light source (C+L wave bands), and light is inputted from single mode optical fiber input terminal, when light wave passes through first
When a long-period gratings LPG1, in a portion energy being coupled to covering, since the length d of intermediate cascaded optical fiber is limited,
The light energy decaying of clad section is limited, so light wave is when by second long-period gratings LPG2, the luminous energy of clad section
Amount can also be coupled to optical fiber, and generate interference with the light in original fiber core layer, then be exported by output end, by spectrum
Instrument receives.When device is not in contact with gas, then cascade length is in the part of d among optical fiber, fibre cladding and sandwich layer transmission
The phase difference of this two-beam remains unchanged.When device contacts are to gas, sensitive layer ZIF-8 leads to sensitivity because having adsorbed gas
The refractive index of layer changes, and changes so as to cause the propagation constant of fibre cladding mould, then this of fibre cladding and sandwich layer transmission
Phase difference changes when two-beam is interfered, therefore after device contacts gas, when the interference spectrum of device is with respect to not in contact with to gas
Interference spectrum start to be moved to the left.Concentration of the gas when just touching device is minimum, as gas is in specific sensing intracavitary
Volatile concentrations gradually increase, and interference spectrum amount of movement also gradually increases.Therefore, gas can be determined according to the amount of movement of interference spectrum
Concentration range.The time of device contacts to gas is longer, and interference spectrum movement is bigger；Otherwise the time is shorter, interference spectrum movement
Amount is just smaller.
The present invention, according to the structure of designed device, makes by taking one section of wave-length coverage near C-band 1550nm as an example
It is 320 microns to go out screen periods, periodicity 50, the cascaded long-period grating senser element that series connection length d is 6 centimetres, ability
Field technique personnel should be noted that here only to facilitate understanding, sensor structure proposed by the invention, light in practical application
The value of grid cycle, periodicity and series connection length d can determine according to specific circumstances, this in being not limited to the present embodiment
Kind, as shown in Fig. 2, the sensor made by the present embodiment is positioned under different gaseous environments, observe in different time points
Device interference spectrum it is opposite not in contact with to gas when interference spectrum amount of movement, include mainly：Test ethyl alcohol shown in Fig. 2 (a) obtains
Spectrogram, the spectrogram that test methanol shown in Fig. 2 (b) obtains, the spectrogram that test ethyl acetate shown in Fig. 2 (c) obtains, figure
The spectrogram that test acetone shown in 2 (d) obtains, the spectrogram that test dichloromethane shown in Fig. 2 (e) obtains, is surveyed shown in Fig. 2 (f)
The spectrogram that examination pyridine obtains, the spectrogram that test ether shown in Fig. 2 (g) obtains, the light that test toluene shown in Fig. 2 (h) obtains
Spectrogram, the spectrogram that test hexamethylene shown in Fig. 2 (i) obtains；Table 1 by interference spectrum under survey gas with various situation of movement.
Table 1 surveys the situation of movement of the interference spectrum under gas with various
| Amount of movement | Ethyl alcohol | Methanol | Acetone | Ethyl acetate | Dichloromethane | Pyridine | Ether | Toluene | Hexamethylene |
| Δλ | 23.45 | 19.29 | 8.70 | 8.75 | 10.61 | 14.42 | 9.71 | 4.85 | 5.40 |
To sum up, the present invention is realized by coating the cascade-connection long period fiber grating structure of metal-organic framework material to not
With the detection of gaseous species, a kind of new gas detection device, fast response time are produced, high sensitivity can be applied to environment
The various aspects such as monitoring and test chemical, have good actual application value.
It, can be in present disclosure it is noted that for those skilled in the art
Make the variation such as several equivalent variations and replacement, such as cascaded long-period grating production parameter such as screen periods, depth and sensitivity
Material ZIF-8 growth thickness variation etc. realizes that the effect of gas recognition detection, these equivalent variations and replacement also should be regarded as this hair
Bright protection domain；In addition other gas detections that the present invention does not demonstrate also should be regarded as protection scope of the present invention.
Those of ordinary skill in the art will understand that the embodiments described herein, which is to help reader, understands this hair
Bright principle, it should be understood that protection scope of the present invention is not limited to such specific embodiments and embodiments.For ability
For the technical staff in domain, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made by
Any modification, equivalent substitution, improvement and etc. should be included within scope of the presently claimed invention.
Claims (5)
1. a kind of Mach of increasing Dare interferometer, which is characterized in that include at least：First long-period fiber grating, the second long period
Fiber grating；It connects between first long-period fiber grating and the second long-period fiber grating a cascaded optical fiber；The grade
Join two-arm of the sandwich layer of optical fiber with covering respectively as interferometer, grows one layer of sensitive layer on the cascaded optical fiber covering.
2. a kind of Mach of increasing Dare interferometer according to claim 1, which is characterized in that the sensitive layer is one layer porous
The metal-organic framework material of ZIF-8.
3. a kind of gas based on metal-organic framework material identifies fibre optical sensor, which is characterized in that including such as claim 2
The Mach increases Dare interferometer.
4. a kind of organic gas detection method, which is characterized in that including：
Coupling of the sandwich layer mould to cladding mode occurs at the first long-period gratings for the sandwich layer light in optical fiber, forms sandwich layer mould and covering
The transmission respectively of mould；
Cascaded optical fiber sensitive layer adsorbs organic gas to be detected so that cladding mode refraction index changing；
In second long-period gratings, the optical coupling of cladding mode returns to sandwich layer to interfere, and obtains interference spectrum；
According to the correspondence between interference spectrum and gas with various, the organic gas to be detected is identified.
5. a kind of organic gas detection method according to claim 4, which is characterized in that the interference spectrum and different gas
Correspondence between body establishes process：
Coupling of the sandwich layer mould to cladding mode occurs at the first long-period gratings for the sandwich layer light in optical fiber, forms sandwich layer mould and covering
The transmission respectively of mould；
Cascaded optical fiber sensitive layer adsorbs known gas so that cladding mode refraction index changing；
In second long-period gratings, the optical coupling of cladding mode returns to sandwich layer to interfere, and obtains interference spectrum；
The correspondence between the known gas is established according to several interference spectrums.
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| CN110261321A (en) * | 2019-06-10 | 2019-09-20 | 暨南大学 | MOF film layer enhanced sensitivity micro-nano elliptical fiber gas sensor and preparation method |
| CN113376105A (en) * | 2021-07-15 | 2021-09-10 | 中南大学 | Optical fiber humidity sensor |
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