CN201749080U - Photoacoustic spectroscopy gas detection system based on distributed feedback fiber laser - Google Patents
Photoacoustic spectroscopy gas detection system based on distributed feedback fiber laser Download PDFInfo
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- CN201749080U CN201749080U CN2010202735870U CN201020273587U CN201749080U CN 201749080 U CN201749080 U CN 201749080U CN 2010202735870 U CN2010202735870 U CN 2010202735870U CN 201020273587 U CN201020273587 U CN 201020273587U CN 201749080 U CN201749080 U CN 201749080U
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- fiber laser
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Abstract
The utility model relates to a photoacoustic spectroscopy gas detection system based on a distributed feedback fiber laser, which belongs to the gas detection technology, and comprises a coherent light source and a distributed feedback fiber laser, wherein the coherent light source is connected with a modulator through an own pigtail, and the modulator is connected to a photoacoustic cell through an ordinary optical fiber to form a sound signal excitation light path; and a 980 pumped semiconductor laser is connected with the 980nm end of a wavelength division multiplexer through a pigtail to form a detection light path with a following light path. The photoacoustic spectroscopy gas detection system based on the distributed feedback fiber laser is characterized in that: the distributed feedback fiber laser is used as a sensor for detecting sound to be fixed in the photoacoustic cell, and one end of the distributed feedback fiber laser is connected to a common port of the wavelength division multiplexer through an ordinary fiber; and the 1550nm end of the wavelength division multiplexer is connected with an isolator, and the output end of the isolator is connected with a far-end wavelength demodulation system through an ordinary optical fiber. The utility model can be normally used in strong electromagnetic and radioactive environments and can be used for detection of special gas environments, facilitates multiplexing, forms networking and realizes multi-point remote control monitoring.
Description
Technical field
The utility model relates to a kind of optoacoustic spectroscopy gas detecting system based on distributed feedback optical fiber laser (DFB-FL) of full optics, specifically is a kind of system that utilizes distributed feedback optical fiber laser to carry out the optoacoustic spectroscopy gas detection as the optics microphone.
Background technology
Optoacoustic effect is based on the effect that inspires sound wave after the material absorbing light modulated by radiationless hot relaxation heat release, has just found optoacoustic effect as far back as Bell in 1880 etc.Carry out in the absorption spectroscopy that gas concentration detects many, optoacoustic spectroscopy has the following advantages: test specification is wide.Photoacoustic technique is the light energy signal that detection material directly absorbs by radiationless transition, rather than the light energy signal of sample is crossed in the measurement transmission, sample is to reflection of incident light like this, scattering can not have influence on measurement result, the sample of fully opaque and high scattering is energy measurement also, measurement range almost spreads all over all states of sample, such as: gas, liquid, Gu, gel, powder, film, colloid etc., but early stage because optoacoustic effect too a little less than, unanimity does not obtain paying attention to, up to the 20 actual seventies, development along with laser technology and feeble signal Detection Techniques, particularly Kreuzer in 1971 utilizes tunable laser to do light source, record the gas absorption spectrum that concentration is low to moderate 10-7 μ g/L, and analyzed the use LASER Light Source theoretically and high sensitivity feeble signal detector can reach 10 to the gas optoacoustic spectroscopy detection limit order of magnitude
-13, after this, photoacoustic spectroscopy is developed rapidly.Another advantage is exactly: photoacoustic signal intensity is directly proportional with incident intensity under the situation that absorption of sample luminous energy does not reach capacity, and along with the development of laser technology, the energy that improves incident light becomes relatively easy to increase detection sensitivity.
Because outstanding advantages such as the high sensitivity that the photoacoustic spectroscopy instrument has, great dynamic range, detection in real time, make people very big interest be arranged to the optoacoustic spectroscopy detection technique, continually develop new light sources, research sound sensing technology and Detection of Weak Signals technology, improve the optoacoustic spectroscopy theory, making analyser various aspects of performance based on optoacoustic spectroscopy have significantly improves, in recent years, on industrial and agricultural production, environmental monitoring, military battlefield, many gas-detecting devices based on optoacoustic spectroscopy had been developed in minimum gas monitoring field in succession.The optoacoustic spectroscopy gas analyzer mainly is made up of six parts: monochromatic source, modulator, photoacoustic cell, sonic transducer, signal amplify and detect data recording and transmission.The photo-acoustic spectrometer of commercial typing seldom generally need design voluntarily according to research object and breadboard condition in actual applications and build.The photoacoustic signal that optoacoustic effect excites is surveyed by highly sensitive sonic transducer, uses electret formula capacitor microphone usually.Its monochromatic source of photo-acoustic spectrometer of general design, the amplification and the detection system of signal are positioned at the scene, but at some special occasions, as 1) strong magnetoelectricity and radioactive environment, because physical characteristics is restricting the operation of common microphone, the influence of outside strong-electromagnetic field can cause the forfeiture of these functions of the equipments even destroy them.Traditional microphone comprises capacitor, electret and dynamic microphone, uses to rely on the electronic circuit that contains capacitor or coil.These electronic packages in microphone are highstrung to interference electronics or electromagnetism; 2) gas environment is such as in the colliery excavation site.Electric spark is forbidden occurring in the scene, this means exciting of coherent source to be placed on long-rangely, with the long-range placement of light source, imports in the photoacoustic cell by optical fiber, and there is the hidden danger of safety in the microphone that also just means electronics; 3) detect in the application in environmental contaminants monitoring and battlefield surroundings toxicity, because gas detection equipment dispersed placement, the scene often can not provide power supply, this just need provide on-the-spot passive, structure is small and exquisite, integrated level and the high photoacoustic cell of high sensitivity, and is convenient with what realize detecting.
＜Proceedings of the CSEE〉2008,28 (34): p40～46. authors are Yun Yuxin, Chen Weigen, Sun Caixin, Pan's Chong, name is called in " the optoacoustic spectroscopy detection method of methane gas in the transformer oil " article and has proposed a kind of novel micro gas detection technology based on optoacoustic effect, have highly sensitive, selectivity is good, advantages such as dynamic detection range is big, but this detection technique is subject to measurement environment, when having outside electromagnetic field, badly influence measuring accuracy, even the function of checkout equipment can be lost.
Summary of the invention
In order to overcome defective and the deficiency that prior art exists, the utility model proposes a kind of optoacoustic spectroscopy gas detecting system of full optics based on distributed feedback optical fiber laser (DFB-FL).
The technical solution of the utility model realizes in the following manner:
A kind of optoacoustic spectroscopy gas detecting system based on distributed feedback optical fiber laser, comprise coherent source, modulator, photoacoustic cell, 980 pumping semiconductor lasers (LD), wavelength division multiplexer (WDM), distributed feedback optical fiber laser (DFB-FL), isolator (ISO) and Wavelength demodulation system, coherent source is connected to modulator by carrying tail optical fiber, modulator is connected to the photoacoustic cell of gaseous environment by long ordinary optic fibre, the periodically variable monochromatic light of light intensity acts on gas to be measured, produce small sound, form the voice signal excitation light path; 980 pumping semiconductor lasers are connected and subsequent optical path composition detection light path by the 980nm end of tail optical fiber and wavelength division multiplexer, it is characterized in that distributed feedback optical fiber laser is fixed in the photoacoustic cell as the sensor of surveying sound, the one end is connected on the common port of wavelength division multiplexer through ordinary optic fibre; The 1550nm end of wavelength division multiplexer is connected with isolator, and the isolator output terminal is connected through the Wavelength demodulation system of ordinary optic fibre and far-end.
Described Wavelength demodulation system is general wavelength demodulation device, and the model of producing as U.S. Optiphase company is the wavelength demodulation device of OPD-4000.
The utility model gas detecting system in use, photoacoustic cell in the utility model system placed the gaseous environment that need to detect or with gas extraction to photoacoustic cell, utilize the microphone of the distributed feedback optical fiber laser of full optical fiber as small sound transducer replacement electronics, when monochromatic light enters photoacoustic cell, behind the gas absorption light to be measured, produce small sound, acoustic pressure causes the drift of DFB-FL wavelength, thereby determine acoustic pressure by the drift that detects wavelength, and then release the concentration of gas.Specifically be after coherent source produces monochromatic light, by modulator, light intensity produces periodic the variation, by be connected to the photoacoustic cell of far-end than long ordinary optic fibre, injects photoacoustic cell, with gas effect to be measured, produces sound.The semiconductor laser of 980nm is connected with the 980nm end of WDM, and the common port output from WDM is connected to DFB-FL by long ordinary optic fibre, and 1550 ends of WDM are linked on the isolator, and the isolator output terminal is connected to Wavelength demodulation system.
The used optoacoustic spectroscopy gas detection principle of prior art is shown in figure (1), coherent source gives off can be by the monochromatic light of gas absorption to be measured, become the monochromatic light of light intensity periodically-varied through the modulation of modulator, enter photoacoustic cell, behind the gas absorption monochromatic light, cause its radiationless relaxation of periodicity, show as the cyclical variation of pressure on the macroscopic view, promptly form sound wave; Sonic transducer changes it into electric signal after detecting pressure wave, and this electric signal is detected by lock-in amplifier or Boxcar integrator, and notes, and also can give remote computer analyzing and processing or deposit.
Concrete action principle of the present utility model is as follows: the semiconductor laser of 980nm, produce the laser of 980nm, enter DFB-FL by WDM, as pump light, excite DFB-FL, produce near the laser of the narrow linewidth of 1550nm, when sound affacts on the DFB-FL, the wavelength shift of DFB-FL, the monochromatic light of the be detected gas absorption that coherent source produces, the laser of formation light intensity periodically-varied after ovennodulation, after entering photoacoustic cell, by gas absorption, produce sound wave, be subjected to the influence of acoustic pressure, the wavelength of packaged DFB-FL is the change of generating period also, because the filter action of WDM, the DFB-FL light of forward direction only enters isolator (ISO), enters Wavelength demodulation system again, we can come out the wavelength change demodulation, wavelength change has been reacted the intensity of acoustic pressure like this, and the concentration of the intensity of acoustic pressure and gas has direct relation, can express the concentration of gas by suitable algorithm.
The utlity model has following advantage: have the highly sensitive while of optoacoustic spectroscopy method, no electronic package is connected on the fibre-optical probe, and any electro permanent magnetic or electrostatic interference are inoperative to microphone, can normally use in forceful electric power magnetic, radioactive environment; The sound-detection system of full optical fiber does not have an effect with flammable explosive gas such as gas, can be used for the detection of special gas environment; Based on the system of optical fiber, be convenient to a plurality of multiplexingly, form network, realize the remote monitor of multiple spot.
Description of drawings
Fig. 1 is the structural representation of prior art optoacoustic spectroscopy gas detection.
Wherein: 1, coherent source, 2, modulator, 3, photoacoustic cell, 4, microphone, 5, signal amplify and the test section, and 6, data recording and hop.
Fig. 2 is the structural representation of the utility model gas detecting system.
Wherein: 7, coherent source, 8, modulator, 9, ordinary optic fibre, 10, photoacoustic cell, 11,980nm diode-end-pumped, 12, wavelength division multiplexer (WDM), 13, ordinary optic fibre, 14, distributed feedback optical fiber laser (DFB-FL), 15, isolator (ISO), 16, Wavelength demodulation system.
Embodiment
Below in conjunction with drawings and Examples the utility model is described further, but is not limited thereto.
Embodiment:
The utility model embodiment as shown in Figure 2, comprise coherent source 7, modulator 8, photoacoustic cell 10,980 pumping semiconductor lasers (LD) 11, wavelength division multiplexer (WDM) 12, distributed feedback optical fiber laser (DFB-FL) 14, isolator (ISO) 15 and Wavelength demodulation system 16, coherent source 7 is connected with modulator 8 by carrying tail optical fiber, modulator 8 is connected to the photoacoustic cell 10 of far-end by longer ordinary optic fibre 9, the periodically variable laser action of light intensity of output is in gas to be measured, produce small sound, form the voice signal excitation light path; 980 pumping semiconductor laser (LD) 11 are connected and subsequent optical path composition detection light path by the 980nm end of tail optical fiber and wavelength division multiplexer (WDM) 12, it is characterized in that distributed feedback optical fiber laser (DFB-FL) 14 is fixed on 10 li of photoacoustic cells as the sensor of surveying sound, on the common port of the wavelength division multiplexer (WDM) 12 of one end through be connected to far-end than long ordinary optic fibre 13; The 1550nm end of wavelength division multiplexer (WDM) 12 is connected with isolator (ISO) 15, and isolator (ISO) 15 output terminals are connected with Wavelength demodulation system 16 through ordinary optic fibre.
Claims (1)
1. optoacoustic spectroscopy gas detecting system based on distributed feedback optical fiber laser, comprise coherent source, modulator, photoacoustic cell, 980 pumping semiconductor lasers, wavelength division multiplexer, distributed feedback optical fiber laser, isolator and Wavelength demodulation system, coherent source is connected to modulator by carrying tail optical fiber, modulator is connected to the photoacoustic cell of gaseous environment by long ordinary optic fibre, the periodically variable monochromatic light of light intensity acts on gas to be measured, produce small sound, form the voice signal excitation light path; 980 pumping semiconductor lasers are connected and subsequent optical path composition detection light path by the 980nm end of tail optical fiber and wavelength division multiplexer, it is characterized in that distributed feedback optical fiber laser is fixed in the photoacoustic cell as the sensor of surveying sound, the one end is connected on the common port of wavelength division multiplexer through ordinary optic fibre; The 1550nm end of wavelength division multiplexer is connected with isolator, and the isolator output terminal is connected through the Wavelength demodulation system of ordinary optic fibre and far-end.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101936878A (en) * | 2010-07-28 | 2011-01-05 | 山东大学 | Photo-acoustic spectrum gas detecting system based on distributed feedback optical fiber laser |
| CN103439268A (en) * | 2013-09-05 | 2013-12-11 | 安徽大学 | High-sensitivity diaphragm type photoacoustic spectrum sensor based on self-mixing |
| CN105444970A (en) * | 2015-11-12 | 2016-03-30 | 新奥科技发展有限公司 | Gas detection system |
| CN105928885A (en) * | 2016-07-04 | 2016-09-07 | 南京航算自控科技有限公司 | All-optical cavity-based Online monitoring device for photoacoustic spectrum transformer |
| CN110361342A (en) * | 2019-07-09 | 2019-10-22 | 华中科技大学 | A kind of more gas optoacoustic spectroscopy detection systems of multiple spot based on all-optical network and method |
| CN110470630A (en) * | 2018-05-11 | 2019-11-19 | 西安电子科技大学 | A kind of distribution type fiber-optic gas sensor based on difference modes |
-
2010
- 2010-07-28 CN CN2010202735870U patent/CN201749080U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101936878A (en) * | 2010-07-28 | 2011-01-05 | 山东大学 | Photo-acoustic spectrum gas detecting system based on distributed feedback optical fiber laser |
| CN103439268A (en) * | 2013-09-05 | 2013-12-11 | 安徽大学 | High-sensitivity diaphragm type photoacoustic spectrum sensor based on self-mixing |
| CN103439268B (en) * | 2013-09-05 | 2016-05-04 | 安徽大学 | Based on the high sensitivity diaphragm type optoacoustic spectroscopy sensor certainly mixing |
| CN105444970A (en) * | 2015-11-12 | 2016-03-30 | 新奥科技发展有限公司 | Gas detection system |
| CN105928885A (en) * | 2016-07-04 | 2016-09-07 | 南京航算自控科技有限公司 | All-optical cavity-based Online monitoring device for photoacoustic spectrum transformer |
| CN110470630A (en) * | 2018-05-11 | 2019-11-19 | 西安电子科技大学 | A kind of distribution type fiber-optic gas sensor based on difference modes |
| CN110361342A (en) * | 2019-07-09 | 2019-10-22 | 华中科技大学 | A kind of more gas optoacoustic spectroscopy detection systems of multiple spot based on all-optical network and method |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20110216 Effective date of abandoning: 20111130 |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20110216 Effective date of abandoning: 20111130 |