CN204177736U - The trace gas detection device in chamber is swung based on two-way light decay - Google Patents
The trace gas detection device in chamber is swung based on two-way light decay Download PDFInfo
- Publication number
- CN204177736U CN204177736U CN201420656737.4U CN201420656737U CN204177736U CN 204177736 U CN204177736 U CN 204177736U CN 201420656737 U CN201420656737 U CN 201420656737U CN 204177736 U CN204177736 U CN 204177736U
- Authority
- CN
- China
- Prior art keywords
- chamber
- light
- swing
- swings
- gas detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The utility model discloses a kind of trace gas detection device swinging chamber based on two-way light decay, belong to gas detection technology field.This trace gas detection device comprises light source cell, light decay swings unit and Signal reception and processing unit, described light source cell comprises interconnective light source, beam splitter, described light decay swings module and comprises two identical light decays and swing chamber, the computing module that described Signal reception and processing unit comprise two photo-detectors and be connected respectively with two photo-detectors, two output terminals of light input end and beam splitter that described two light decays swing chamber are connected respectively, and two light decays swing declining of chamber and swing light signal output end and be connected respectively with two photo-detectors.Compared to existing technology, the utility model utilizes two-way light decay to swing chamber and obtains two simultaneously and decline and swing curve, thus can obtain the concentration of gas to be measured quickly and easily.
Description
Technical field
The utility model relates to a kind of trace gas detection device swinging chamber based on light decay, particularly relates to a kind of trace gas detection device swinging chamber based on two-way light decay, belongs to gas detection technology field.
Background technology
Along with the development of oil, coal, chemical industry, auto industry, in human production activity's process, create a large amount of contaminated environment, poisonous and harmful, inflammable and explosive waste gas.Although these gas concentration are very low, there is impact in various degree, so trace gas analysis detection technique exists application demand widely at numerous areas to the aspect such as health, atmospheric environment of the mankind.
Cavity ring down spectroscopy technology (Cavity Ring Down Spectroscopy, CRDS) be the highly sensitive absorption spectrum detection technique of one developed rapidly over nearly 20 years, there is high sensitivity and resolution, and not by the impact of light source light-intensity variation, be applicable to the measurement of Weak Absorption spectrum.After the people such as O ' Keefe in 1998 propose pulsed light Research on Cavity Ring Down Spectroscopy, the research of optical cavity ring-down technology in spectral measurement is increasingly extensive.
At first, CRDS is based upon on the optical resonator of two high reflection mirrors formation, obtains the loss information in chamber by the light intensity attenuation speed measured in resonator cavity.Owing to must ensure the high reverse--bias low loss characteristic of resonator cavity, namely require carry out high reflectance coating to two catoptrons and ensure that chamber mirror is accurately aimed at, the application development of CRDS under some certain environmental conditions is restricted.In succession occurred after calendar year 2001 fiber optic loop decline swing chamber, the coating of fine end declines and swings chamber and Fiber Bragg Grating swings chamber to declining, these optical-fiber types decline and swing chamber and not only improve above-mentioned tradition and decline and swing the limitation in chamber, and respectively there is unique superiority, for absorbing detection, the sensory field of various gas liquid.Calendar year 2001, the people such as Stewart propose a kind of Active Optical Fiber ring Research on Cavity Ring Down Spectroscopy first, system adopts Distributed Feedback Laser to make light source, excites the fiber optic loop acquisition formed by coupling mechanism connecting fiber to decline and swings signal, introduce gas absorption cell and detect tracer gas in fiber optic loop.Due to the insertion loss very large (about 1dB) of absorption cell, cause the ring-down time in chamber very little (about 100ns), therefore the er-doped gain fibre adding one section of 980nm laser pump (ing) in fiber optic loop compensates the light signal of excessive loss in ring, obtains the ring-down time of micron dimension.But its defect is the complicacy adding system improving accuracy of detection while, and be difficult to control and realize gain compensation stable near wavelength 1550nm.2002, the people such as Brown propose a kind of passive fiber ring and decline and swing chamber, one section of multimode optical fiber is bent to ring and connects with the joints of optical fibre, by the knee irradiating optical fiber, light pulse is coupled into fiber optic loop, the transmission signal in another knee is received with photomultiplier, obtain two index to decline and swing signal, the decay of light pulse in fibre cladding and fibre core in corresponding ring respectively, this device is directly by fibre-optical bending Cheng Huan, between the fiber end face aimed at or introduce organic dyestuff in microcavity and carry out sensing, system total losses are lower, ring-down time is large, structure is simple, the analysis to optical fiber telecommunications system loss mechanism and the high-precision sensing to micro fluid can be realized.But its defect is ring-down time to fall short of, and thus sensing range is less.2004, the people such as Tarsa and Lehmann decline to swing in chamber in fiber optic loop and introduce one section of double-tapered fiber as sensing unit, by detection fiber bipyramid leak evanscent field absorption survey the concentration of octyne solution, obtain result and be better than other evanescent wave absorbing detection methods.They are also applied to bend, axial strain is measured, and by the single-mode fiber ring of one section of single mode bicone intelligent acess 2.2Km, apply axial strain by the conversion platform of step motor control.Because the design of optical fiber bipyramid is unreasonable, ring-down time to axial displacement presents nonlinear response, and sensitivity is also not high enough, needs to be optimized design.2007, the people such as Andachi utilize tunable picosecond pulse laser to encourage Bragg grating to decline respectively to swing chamber and fiber optic loop to decline to swing chamber, the microgap opening one 100 μm in fiber optic loop carries out absorption detecting for introducing methylene blue fuel, obtains lower minimum detectable level.
The above-described existing trace gas detection device based on CRDS respectively has its relative merits, but, these pick-up units existing are all use single declining to swing chamber and successively measure twice ring-down time, after having surveyed the ring-down time without gas to be measured, introduce tested gas not easy to operate, easy introducing impurity gas, reduces accuracy of detection, cannot conveniently measure to decline for twice simultaneously and swing curve.
Utility model content
Technical problem to be solved in the utility model is to overcome prior art deficiency, a kind of trace gas detection device swinging chamber based on two-way light decay is provided, utilize two-way light decay to swing chamber to obtain two simultaneously and decline and swing curve, thus the concentration of gas to be measured can be obtained quickly and easily.
The utility model specifically solves the problems of the technologies described above by the following technical solutions:
Swing the trace gas detection device in chamber based on two-way light decay, comprise light source cell, light decay swings unit and Signal reception
With processing unit, described light source cell comprises interconnective light source, beam splitter, described light decay swings module and comprises two identical light decays and swing chamber, the computing module that described Signal reception and processing unit comprise two photo-detectors and be connected respectively with two photo-detectors, two output terminals of light input end and beam splitter that described two light decays swing chamber are connected respectively, and two light decays swing declining of chamber and swing light signal output end and be connected respectively with two photo-detectors.
Light decay in technique scheme swings the optical resonator that chamber can adopt two high reflection mirrors to be formed, or optical fiber declines and swings that chamber etc. is existing maybe will technology, considers that optical fiber declines and swings the various advantages that chamber has, and preferably, it is that optical fiber declines and swings chamber that described light decay swings chamber.
Compared to existing technology, the utility model has following beneficial effect:
The utility model utilizes the light decay of two-way parallel connection to swing chamber and can obtain two simultaneously and decline and swing curve, thus can treat side gas quickly and easily and measure; The utility model adopts optical fiber to decline to swing chamber further, solve traditional high reverse--bias mirror decline swing chamber due to the light path of roundtrip large not, the problem that ring-down time is little, measuring accuracy is higher.
Accompanying drawing explanation
Fig. 1 is the structural representation of the utility model preferred embodiment; In figure, each label implication is as follows:
1, light source; 2,
fiber coupler (splitting ratio is 50:50); 3 and 4, isolator; 5,6,9 and 10, Fiber Bragg Grating FBG; 7 and 8, photonic crystal fiber; 11 and 12, condenser lens; 13 and 14, photodetector; 15 and 16, data collecting card; 17, computing machine.
Embodiment
Below in conjunction with accompanying drawing, the technical solution of the utility model is described in detail:
The utility model swings the trace gas detection device in chamber based on two-way light decay, comprise light source cell, light decay swings unit and Signal reception and processing unit, described light source cell comprises interconnective light source, beam splitter, described light decay swings module and comprises two identical light decays and swing chamber, the computing module that described Signal reception and processing unit comprise two photo-detectors and be connected respectively with two photo-detectors, two output terminals of light input end and beam splitter that described two light decays swing chamber are connected respectively, two light decays swing declining of chamber and swing light signal output end and be connected respectively with two photo-detectors.
Light decay in the utility model swings chamber and can adopt and variously existingly maybe will have technology, and the utility model preferably adopts optical fiber to decline to swing chamber, and fiber optic loop especially wherein declines and swings chamber, the coating of fine end declines swings chamber or fiber grating and decline and swing chamber.
In order to the light preventing light decay from swinging in chamber has an impact to light source and beam splitter, the utility model swings at each light decay further and is provided with one in the connection light path of chamber and described beam splitter light can be made to light decay by beam splitter to be swung the optoisolator transmitted in chamber, thus can effectively prevent the light decay light swung in chamber from entering beam splitter and light source.
Light source preferred fiber pulsed laser in the utility model, the preferred 50:50 beam splitter of beam splitter.
Fig. 1 shows a preferred embodiment of the present utility model, and this measurement mechanism comprises light source cell, light decay swings unit and Signal reception and processing unit.As shown in Figure 1, light source cell comprises light source 1 He
fiber coupler (or claiming beam splitter) 2; Light decay swings unit and comprises the Fiber Bragg Grating FBG (FBG) 5,9 connected by photonic crystal fiber 7 for a pair, with the Fiber Bragg Grating FBG 6,10 to be connected by photonic crystal fiber 8 for a pair, photonic crystal fiber only can support a mode transfer in very wide bandwidth range, there is high nonlinear factor, be conducive to reducing loose look loss when light source transmits in a fiber, and there is the photonic crystal fiber that aperture is larger, can order of reflection be increased as air chamber, effectively improve measuring accuracy; As shown in the figure,
two output terminals of fiber coupler 2 are connected with Fiber Bragg Grating FBG 5, Bragg grating 6 via optoisolator 3, optoisolator 4 respectively; Signal reception and processing unit comprise the photodetector 13, the photodetector 14 that are arranged at respectively after Fiber Bragg Grating FBG 9, Fiber Bragg Grating FBG 10, the data collecting card 15 be connected with photodetector 13, photodetector 14 respectively, data collecting card 16, and the computing machine 17 be connected with data collecting card 15, data collecting card 16; In order to strengthen light signal collection, in the present embodiment, between Fiber Bragg Grating FBG 9 and electric explorer 13 and between Fiber Bragg Grating FBG 10 and detector 14, be also respectively arranged with condenser lens 11 and condenser lens 12.
Fiber Bragg Grating FBG 5, photonic crystal fiber 7, Fiber Bragg Grating FBG 9 form a road fiber grating and decline and swing chamber, and Fiber Bragg Grating FBG 6, photonic crystal fiber 8, Fiber Bragg Grating FBG 10 form another road fiber grating and decline and swing chamber.The decline parameter such as material, length, diameter of each component parts swinging chamber of two fiber gratings is identical.
The light warp that light source 1 sends
fiber coupler 2 is divided into two-way, enter two fiber gratings via optoisolator 3, optoisolator 4 respectively to decline and swing chamber form vibration wherein, declining after photodetector 13, photodetector 14 receive respectively and converge via condenser lens 11 and condenser lens 12 is swung light signal and is converted into electric signal, rear input computing machine 17 is gathered via data collecting card 15, data collecting card 16, computing machine 17 can be drawn out two fiber gratings according to gathered signal and decline and swing declining in chamber and swing curve, and then is finally inversed by the concentration information of gas to be measured.
According to the ultimate principle of cavity ring down spectroscopy technology and the Beer law of absorption spectrum, along with declining of light wave is swung, the light intensity signal with exponential damping can be detected outside chamber
for:
In formula,
the initial beam intensity incided in chamber,
it is the ring-down time in chamber.Ring-down time is derived by calculating
for:
In formula,
that chamber is long,
the light velocity,
the absorption coefficient of gas,
the concentration of tested gas,
it is the reflectivity of two chamber mirrors.Declined by matching two optical fiber again and swing the ring-down time in chamber
with
, inverting obtains trace gas concentration.
When using above device to carry out the detection of trace gas, its idiographic flow is as follows:
1), light source 1 start after, the laser sent through splitting ratio be 50:50's
fiber coupler, by
it is the light that the two-way intensity of original light intensity half is equal that light source is divided into light intensity by fiber coupler;
2), decline to swing in chamber at (or lower road) optical fiber of setting out on a journey and pour the known high concentration marked gas of concentration, this light path is made to be passage I, decline to swing in chamber at Xia Lu (or setting out on a journey) optical fiber and pour gas to be measured, this light path is made to be passage II, after primary light source is divided into two-way light source, simultaneously by the isolator in passage I and passage II, and enter two optical fiber simultaneously and decline and swing in chamber, form vibration wherein respectively;
3) what, photodetector 13 and 14 two optical fiber received respectively after condenser lens 11 and 12 focuses on declined and swing that chamber exports declines and swings light signal, and after being converted into electric signal, carry out data acquisition by data collecting card 15 and 16 and export computing machine 17 to, obtaining declining of marked gas and swing curve and declining of gas to be measured swings curve;
4) the declining of marked gas obtained is established to swing curve
, and declining of gas to be measured swings curve
, swing according to declining of marked gas the ring-down time that marked gas is derived in curve calculating
, and swing according to declining of gas to be measured the ring-down time that gas to be measured is derived in curve calculating
.By ring-down time
with
expression formula is known, ring-down time
about absorption coefficient
function, marked gas concentration
known, after measuring system is determined, light path
with the reflectivity of Fiber Bragg Grating FBG
be all definite value, then by the method for matching, the concentration of gas to be measured can be finally inversed by
.
It should be noted that, signals collecting involved in above-mentioned measuring process, signal transacting, the concentration etc. of swinging Drawing of Curve and swinging log inversion gas to be measured according to declining that declines are existing mature technology, the not contribution made prior art of the utility model.The utility model is the improvement of pick-up unit hardware configuration to the contribution done by prior art.
Claims (7)
1. the trace gas detection device in chamber is swung based on two-way light decay, comprise light source cell, light decay swings unit and Signal reception and processing unit, it is characterized in that, described light source cell comprises interconnective light source, beam splitter, described light decay swings module and comprises two identical light decays and swing chamber, the computing module that described Signal reception and processing unit comprise two photo-detectors and be connected respectively with two photo-detectors, two output terminals of light input end and beam splitter that described two light decays swing chamber are connected respectively, two light decays swing declining of chamber and swing light signal output end and be connected respectively with two photo-detectors.
2. trace gas detection device as claimed in claim 1, is characterized in that, it is that optical fiber declines and swings chamber that described light decay swings chamber.
3. trace gas detection device as claimed in claim 2, is characterized in that, described optical fiber decline swing chamber be fiber optic loop decline swing chamber, the coating of fine end declines and swings chamber or fiber grating and decline and swing chamber.
4. trace gas detection device as claimed in claim 3, is characterized in that, described optical fiber declines and swings chamber is that fiber grating declines and swings chamber, comprises the Fiber Bragg Grating FBG connected by photonic crystal fiber for a pair.
5. trace gas detection device as claimed in claim 1, it is characterized in that, described beam splitter is 50:50 beam splitter.
6. trace gas detection device as claimed in claim 1, it is characterized in that, described light source is fiber pulse laser.
7. trace gas detection device as claimed in claim 1, is characterized in that, swings in the connection light path of chamber and described beam splitter to be provided with one light can be made to light decay by beam splitter to be swung the optoisolator transmitted in chamber at each light decay.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420656737.4U CN204177736U (en) | 2014-11-06 | 2014-11-06 | The trace gas detection device in chamber is swung based on two-way light decay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420656737.4U CN204177736U (en) | 2014-11-06 | 2014-11-06 | The trace gas detection device in chamber is swung based on two-way light decay |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204177736U true CN204177736U (en) | 2015-02-25 |
Family
ID=52566541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420656737.4U Expired - Fee Related CN204177736U (en) | 2014-11-06 | 2014-11-06 | The trace gas detection device in chamber is swung based on two-way light decay |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204177736U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105319173A (en) * | 2015-11-25 | 2016-02-10 | 上海禾赛光电科技有限公司 | Gas remote sensing detection device and method |
| CN106018205A (en) * | 2016-07-15 | 2016-10-12 | 中国科学技术大学先进技术研究院 | Measurement device and measurement method for particle size and content of aerosol |
| CN106680218A (en) * | 2016-12-29 | 2017-05-17 | 中国人民解放军国防科学技术大学 | Optical fiber ring-down cavity for gas concentration measuring system, and gas concentration measuring system and method |
| CN109682777A (en) * | 2019-02-28 | 2019-04-26 | 山东非金属材料研究所 | A kind of system based on trace amounts of methane content in cavity ring down spectroscopy technology detection ultra-pure gases |
| CN111103260A (en) * | 2020-01-21 | 2020-05-05 | 江苏师范大学 | System and method for detecting intermediate infrared all-fiber cavity ring-down trace gas |
-
2014
- 2014-11-06 CN CN201420656737.4U patent/CN204177736U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105319173A (en) * | 2015-11-25 | 2016-02-10 | 上海禾赛光电科技有限公司 | Gas remote sensing detection device and method |
| CN105319173B (en) * | 2015-11-25 | 2018-07-20 | 上海禾赛光电科技有限公司 | Gas remote measurement device and method |
| CN106018205A (en) * | 2016-07-15 | 2016-10-12 | 中国科学技术大学先进技术研究院 | Measurement device and measurement method for particle size and content of aerosol |
| CN106680218A (en) * | 2016-12-29 | 2017-05-17 | 中国人民解放军国防科学技术大学 | Optical fiber ring-down cavity for gas concentration measuring system, and gas concentration measuring system and method |
| CN109682777A (en) * | 2019-02-28 | 2019-04-26 | 山东非金属材料研究所 | A kind of system based on trace amounts of methane content in cavity ring down spectroscopy technology detection ultra-pure gases |
| CN109682777B (en) * | 2019-02-28 | 2024-01-23 | 山东非金属材料研究所 | System for detecting trace methane content in ultra-high purity gas based on cavity ring-down spectroscopy |
| CN111103260A (en) * | 2020-01-21 | 2020-05-05 | 江苏师范大学 | System and method for detecting intermediate infrared all-fiber cavity ring-down trace gas |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN204177736U (en) | The trace gas detection device in chamber is swung based on two-way light decay | |
| CN108332876B (en) | Optical fiber temperature sensor | |
| CN102323239B (en) | Refractive index sensor based on asymmetric double-core optical fiber | |
| CN102980681B (en) | A kind of distributed strain based on Brillouin scattering and optical fiber temperature sensor | |
| CN103017687B (en) | Orthogonal polarization fiber bragg grating vector torsion sensing device and detection method thereof | |
| CN203025082U (en) | Refractive index sensor based on LPG-TFBG (Long Period Grating-Tilted Fiber Bragg Grating) structure | |
| CN105044030A (en) | Coupling refractive index meter for evanescent field among optical fibers and detecting method of coupling refractive index meter | |
| CN109959403B (en) | Multi-parameter large-capacity sensing system | |
| CN102262062A (en) | Microstructure fiber Bragg grating gas sensor and detection device | |
| CN102279164A (en) | Difference measurement method and device for low moisture content of fiber bragg grating with double wavelengths and double light paths | |
| CN110260920A (en) | Temperature and refractive index dual sampling device based on directional coupler and long-period fiber grating | |
| CN201637666U (en) | Dynamic measuring instrument of solution concentration | |
| CN104062236A (en) | Atmospheric visibility detection device based on cavity ring-down technology and application method | |
| CN204556023U (en) | Based on two parameteric light fiber sensors of polarization maintaining optical fibre | |
| CN109490233A (en) | The strength investigation type gas sensor of enhanced sensitivity and photothermal technique is cascaded based on FP interferometer | |
| CN109507132A (en) | Spectrographic detection type gas sensor based on double optical fiber FP interferometer parallel-connection structures | |
| CN108872148A (en) | High-precision particulate in air concentration detection method based on Fibre Optical Sensor | |
| CN101377527A (en) | Optical fiber voltage measuring instrument | |
| CN101710065A (en) | Thin core optical fiber mode interferometer sensor | |
| CN207263633U (en) | A kind of fibre optic interferometer gas sensor based on free-air chamber | |
| CN106248602A (en) | Hydrogen sulfide gas sensing device based on optical fiber F P interferometer | |
| CN109580037A (en) | Temperature sensor and preparation method thereof based on photonic crystal fiber FP structure | |
| CN109507128A (en) | Strength investigation type gas sensor based on FP interferometer parallel-connection structure and photothermal technique | |
| CN203811537U (en) | Refraction index and temperature measurement sensor based on LPFG (Long Period Fiber Grating) | |
| CN109001155A (en) | A kind of humidity measuring method based on low gain low noise optical fiber cavity attenuation and vibration technique |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150225 Termination date: 20161106 |