CN203025081U - Volatile organic compound sensor based on long-period optical grating of photonic crystal fiber - Google Patents
Volatile organic compound sensor based on long-period optical grating of photonic crystal fiber Download PDFInfo
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- CN203025081U CN203025081U CN 201220571234 CN201220571234U CN203025081U CN 203025081 U CN203025081 U CN 203025081U CN 201220571234 CN201220571234 CN 201220571234 CN 201220571234 U CN201220571234 U CN 201220571234U CN 203025081 U CN203025081 U CN 203025081U
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Abstract
The utility model relates to a volatile organic compound sensor based on a long-period optical grating of a photonic crystal fiber. The long-period optical grating of the photonic crystal fiber is completely placed into a sleeve; two single-mode optical fibers are respectively inserted into the sleeve from the two sides of the sleeve to be close to but not in contact with the end face of the long-period optical grating of the photonic crystal fiber, so that un-fused light collimation is realized; and the other ends of the two single-mode optical fibers are respectively connected with an output end of a broadband light source and an input port of a spectrograph through optical fibers. Light is transmitted in the photonic crystal fiber and is subjected to the effect of the long-period optical grating, and thus emergent light has a resonant peak. A resonant wavelength is related to the concentration of volatile organic compounds in a cladding air hole of the photonic crystal fiber, and thus the detection on the concentration of the volatile organic compounds can be realized through monitoring the movement of the resonant wavelength. The volatile organic compound sensor based on the long-period optical grating of the photonic crystal fiber is compact in structure, can be for repeated measurement for a long period, is high in sensitivity and aims at solving the problems in an existing volatile organic compound sensor technology that the detection cost is high and long-period repeated measurement and trace detection are difficult to realize.
Description
Technical field
The utility model belongs to technical field of optical fiber sensing, is specifically related to a kind of volatile organic matter sensor based on photonic crystal fiber long-period gratings (Photonic crystal fiber-Long period grating, PCF-LPG).
Background technology
Volatile organic matter (volatile organic compounds, VOCs) be modal class air pollutants, be commonly referred to as boiling point at 50～250 ℃, the organism of steam be can form at normal temperatures and pressures, benzene homologues, organic chloride, freon series, organic ketone, alcohols, amine, ether and ester class etc. mainly comprised.VOCs has toxicity, pungency and carcinogenicity, can the havoc environmental and human health impacts.Therefore, development is sensitive, fast, the method for VOCs content is very important in the Accurate Determining air.
In existing detection method, due to the particular advantages of optical fiber, for example volume is little, and loss is low, is suitable for remote detection etc., detects based on the volatile organic matter of optical fiber more and more to be subject to people's attention.Simple, Practical Determination Method of VOCs kind based on optical fiber is a lot, and the modal method that is based on spectral analysis detects to analyze to the characteristic absorpting spectruming line of gas to be measured and obtains gas concentration to be measured.This detection method is highly sensitive, and response is fast, but the absorption spectra scope that often needs special light source to mate variety classes gas to be measured, so cost is high, has limited its range of application.Detect also report to some extent based on the volatile organic matter of fiber grating, gas to be measured acts on the fiber grating outside, by the fibre core that affects fiber grating, the drift that cladding-effective-index causes resonance wavelength.But the inscription meeting of grating causes damage to optical fiber, is difficult to long-term use.
For the problems referred to above, we have proposed a kind of volatile organic matter sensor based on the photonic crystal fiber long-period gratings.This sensor construction is compact, and the trace monitoring is convenient in duplicate measurements for a long time, and is highly sensitive, has simultaneously the characteristic that the photonic crystal fiber resisting temperature is disturbed, and can well realize the detection of variety classes volatile organic matter.
Summary of the invention
The utility model purpose is exactly that the testing cost that exists in the existing volatile organic matter sensing technology of solution is high, be difficult to realize the problem of long-term duplicate measurements and trace detection, a kind of compact conformation, duplicate measurements for a long time, the highly sensitive volatile organic matter sensor based on the photonic crystal fiber long-period gratings are provided.
A kind ofly realize the volatile organic matter sensor based on the photonic crystal fiber long-period gratings, comprise a wideband light source, two single-mode fibers, one section photonic crystal fiber long-period gratings, a sleeve and a spectrometer.Be placed in the photonic crystal fiber long-period gratings in sleeve fully, two single-mode fibers are inserted in sleeve from sleeve both sides respectively, approach but do not come in contact with the end face of photonic crystal fiber long-period gratings, realize the optical alignment of not welding, the other end of two single-mode fibers is connected input port fiber with the output terminal of wideband light source respectively and is connected with spectrometer.
Described sleeve diameter is 126～127 μ m, and sleeve two ends are than the long 2～4cm of photonic crystal fiber long-period gratings, and the part that grows has the reticulate texture of hollow out through pre-service.
The beneficial effect that the utility model has is:
1. has the airport structure of a large amount of micron dimensions in the covering of photonic crystal fiber.Through after volatilize and diffusing into the airport of photonic crystal fiber covering, more direct to the effect of the effective refractive index of the core of photonic crystal fiber and cladding mode as VOCs, increase measurement sensitivity.And photonic crystal fiber long-period gratings two ends and two single-mode fibers be the optical alignment mode of welding not, can so that the VOCs molecule is easy to discharge, be convenient to duplicate measurements.
2. the photonic crystal fiber long-period gratings has photonic crystal fiber to the insensitive characteristic of temperature variation, makes measuring process not be subjected to the impact of ambient temperature, has avoided temperature that measurement is impacted, and improves measuring accuracy.
3. whole sense measuring device has compact conformation, and the trace monitoring is convenient in duplicate measurements for a long time, and is highly sensitive, can well realize the detection of variety classes volatile organic matter.
Description of drawings
Fig. 1 is structural drawing of the present utility model;
Fig. 2 is the detail view at the utility model sensing position.
Embodiment
Below in conjunction with accompanying drawing, the utility model is further described.
As shown in Figure 1, a kind ofly realize the volatile organic matter sensor based on the photonic crystal fiber long-period gratings, mainly comprise wideband light source 1, two single-mode fibers 2, photonic crystal fiber long-period gratings 3, sleeve 4, spectrometer 5.
Photonic crystal fiber long-period gratings 3 is placed in sleeve 4 fully, two single-mode fibers 2 are inserted in sleeves 4 from sleeve 4 both sides respectively, approach but do not come in contact with the end face of photonic crystal fiber long-period gratings 3, realize the optical alignment of not welding, the other end of two single-mode fibers 2 is connected with the input port fiber that the output terminal of wideband light source 1 is connected with spectrometer respectively.
Utilize this sensing device to realize that the method for volatile organic matter sensing comprises the following steps:
Step (1) is selected the wideband light source that output wavelength is 1500nm to 1600nm, the spectrometer of two single-mode fibers and an operation wavelength covering 1500nm to 1600nm, and utilize carbon dioxide laser to inscribe a long-period gratings on photonic crystal fiber, make the photonic crystal fiber long-period gratings;
it is in 126～127 μ m sleeves that step (2) is placed in an internal diameter fully with the photonic crystal fiber long-period gratings of making, the sleeve two ends are than the long 2～4cm of photonic crystal fiber long-period gratings, the part that grows has the reticulate texture of hollow out through pre-service, two single-mode fibers are inserted in sleeve from sleeve both sides respectively, approach but do not come in contact with the end face of photonic crystal fiber long-period gratings, due to the internal diameter of sleeve only than large 1～2 μ m of fibre diameter, single-mode fiber and photonic crystal fiber long-period gratings can be good at realizing the optical alignment of not welding, the other end of two single-mode fibers is connected input port fiber with the output terminal of wideband light source respectively and is connected with spectrometer,
Step (3) is placed in volatile organic matter environment to be detected with the sleeve of built-in good optical fiber in step (2).Based on inscribing on photonic crystal fiber, long-period gratings is arranged, light propagates in photonic crystal fiber and through the long-period gratings effect, emergent light has harmonic peak, and resonance wavelength is relevant with the effective refractive index of photonic crystal fiber cladding mode and core mode:
λ＝n
co(C)-n
cl(C)]Λ
N wherein
co(C) be the effective refractive index of photonic crystal fiber core, n
cl(C) be the effective refractive index of photonic crystal fiber cladding mode, they all with photonic crystal fiber covering airport in the volatile organic matter concentration C funtcional relationship is arranged, Λ is the grid cycle of long-period gratings.Therefore, engraved structure place via sleeve diffuses in sleeve when volatile organic matter, and further diffuse into the covering airport of photonic crystal fiber, can change the effective refractive index of cladding mode and core mode, thereby observe the variation of resonance wavelength, the movement by monitoring resonance wavelength can realize detection to concentration.
The grid cycle Λ of the photonic crystal fiber long-period gratings that uses in this example is 160 μ m, covering airport refractive index n=1 o'clock resonance wavelength is 1533.87nm, record the corresponding resonance wavelength of methanol reagent of corresponding different volumes mark, its result such as table one.
The variation relation of methyl alcohol volume fraction and resonance wavelength in table one air
In air the volume fraction of methyl alcohol from 0% (being without methanol molecules airport) in 5% scope, the resonance wavelength of photonic crystal fiber long-period gratings is changed to 1566.72nm from 1533.87nm, variable quantity is about 33nm, and variation range is very large, is easy to read.As can be seen from the table, in air, the resonance wavelength of the content of methyl alcohol and photonic crystal fiber long-period gratings is approximate linear.Choose from 0% (being without methanol molecules airport) and observe to 1% scope, the volume fraction that is methyl alcohol in air changes 1%, the resonance wavelength drift value offset Δ λ ≈ 6nm of photonic crystal fiber long-period gratings, the resolution of spectrometer is 10pm, can get thus, the measuring accuracy of sensor described in the utility model is 1.7 * 10
-5, namely in air, the volume fraction of methyl alcohol changes when surpassing 0.0017%, all can be recorded by this sensor, illustrates that this sensor has very high sensitivity.
But the gordian technique that the utility model can be realized the volatile organic matter sensing measurement and have a higher sensitivity duplicate detection is:
1. has the airport structure of a large amount of micron dimensions in the covering of photonic crystal fiber.Through after volatilize and diffusing into the airport of photonic crystal fiber covering, more direct to the effect of the effective refractive index of the core of photonic crystal fiber and cladding mode as VOCs, increase measurement sensitivity.And photonic crystal fiber long-period gratings two ends and two single-mode fibers be the optical alignment mode of welding not, can so that the VOCs molecule is easy to discharge, be convenient to duplicate measurements.
2. the photonic crystal fiber long-period gratings has photonic crystal fiber to the insensitive characteristic of temperature variation, makes measuring process not be subjected to the impact of ambient temperature, has avoided temperature that measurement is impacted, and improves measuring accuracy.
Single-mode fiber in the present embodiment is common SMF-28 single-mode fiber; The cladding diameter of photonic crystal fiber long-period gratings is 125 μ m, and core diameter is 7 μ m, and covering airport diameter is 3.06 μ m, and pitch of holes is 5.61 μ m, and the grid cycle of long-period gratings is 160 μ m.
Claims (1)
1. the volatile organic matter sensor based on the photonic crystal fiber long-period gratings, comprise wideband light source, single-mode fiber, photonic crystal fiber long-period gratings, sleeve and spectrometer, it is characterized in that:
Be placed in the photonic crystal fiber long-period gratings in sleeve fully, two single-mode fibers are inserted in sleeve from sleeve both sides respectively, approach but do not come in contact with the end face of photonic crystal fiber long-period gratings, realize the optical alignment of not welding, the other end of two single-mode fibers is connected input port fiber with the output terminal of wideband light source respectively and is connected with spectrometer; Described sleeve diameter is 126～127 μ m, and sleeve two ends are than the long 2～4cm of photonic crystal fiber long-period gratings, and the part that grows has the reticulate texture of hollow out through pre-service.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220571234 CN203025081U (en) | 2012-10-26 | 2012-10-26 | Volatile organic compound sensor based on long-period optical grating of photonic crystal fiber |
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| CN 201220571234 CN203025081U (en) | 2012-10-26 | 2012-10-26 | Volatile organic compound sensor based on long-period optical grating of photonic crystal fiber |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102914516A (en) * | 2012-10-26 | 2013-02-06 | 中国计量学院 | Method and device for sensing volatile organic compound based on long-period grating of photonic crystal fiber |
| CN108362665A (en) * | 2018-03-23 | 2018-08-03 | 中国计量大学 | A kind of combination microstructured optical fibers and micro-fluidic acidometer |
-
2012
- 2012-10-26 CN CN 201220571234 patent/CN203025081U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102914516A (en) * | 2012-10-26 | 2013-02-06 | 中国计量学院 | Method and device for sensing volatile organic compound based on long-period grating of photonic crystal fiber |
| CN108362665A (en) * | 2018-03-23 | 2018-08-03 | 中国计量大学 | A kind of combination microstructured optical fibers and micro-fluidic acidometer |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130626 Termination date: 20141026 |
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| EXPY | Termination of patent right or utility model |