CN104280345A - Tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor - Google Patents
Tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor Download PDFInfo
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- CN104280345A CN104280345A CN201410554051.9A CN201410554051A CN104280345A CN 104280345 A CN104280345 A CN 104280345A CN 201410554051 A CN201410554051 A CN 201410554051A CN 104280345 A CN104280345 A CN 104280345A
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Abstract
The invention discloses a tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor. The tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor comprises a laser source (1), a plurality of sensing units (5) and a phase-locking amplifier (6), wherein the sensing units (5) are cascaded by an optical fiber and distributed in one area; the laser output by the laser source (1) is transmitted to a first-level sensing unit (5) by virtue of a distributed optical fiber (4); the laser output by the first-level sensing unit (5) is used as incident light and enters a second-level sensing unit (5), so the cascading utilization of the laser energy can be achieved in a similar manner; detection signals output by the sensing units (5) are sent to the phase-locking amplifier (6); the output of the phase-locking amplifier (6) is connected with a control terminal (7); and the control terminal (7) is used for displaying and alarming the input detection signals. The tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor is efficient and reliable, and is high in sensitivity and strong in adaptability.
Description
Technical field
The present invention relates to a kind of gas detection technology field, be specifically related to a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser.
Background technology
Along with the development of the subjects such as life science, material science, artificial intelligence, gas sensor has important using value in atmospheric surveillance, food industry, the quick the real time measure of vehicle exhaust, toxic gas detection safety inspection, Aero-Space, medical diagnosis and anti-terrorism are explosion-proof etc.It is high that the infrared optics formula gas sensor being representative with infrared absorption gas Cleaning Principle has precision, selectivity is good, reliably sensitive, reaction is fast, measurement range is wide, not poisoning, do not rely on oxygen, less by environmental interference factor, life-span length waits remarkable advantage, but be subject to infrared gas sensor complex structure a few years ago, the developmental limitation of high in cost of production condition is slow, along with the development of semiconductor laser technology, the quantum cascade laser of middle-infrared band and the invention of interband cascade lasers are high sensitivity, the trace gas infrared optics formula of high selectivity detects and provides effective light source, and along with continuing to bring out of novel simple sensor structure, optical type gas sensor growth momentum was powerful in recent years, it is the study hotspot of gas sensor domain.
The state of development of integrated gas detection technique, the development of optical fiber gas sensing technology is from utilizing simple wide spectrum light source to high stable narrow-band tunable light source, from traditional spot measurement to multiple spot or even large-scale distributed detection, detect from pure gas and measure multiple gases simultaneously, measure limit and also reach ppb magnitude from blast limit, measurement sensistivity is also improving constantly, and system cost is more and more lower.
The system of carrying out gas detect in conjunction with quartz tuning fork strengthened optoacoustic spectroscopy gas detection technology and Distributed Optical Fiber Sensing Techniques at present have not been reported.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, a kind of efficient, reliable, highly sensitive, adaptable a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser is provided.
The object of the invention is to be achieved through the following technical solutions:
A kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser, it comprises lasing light emitter, multiple sensing unit and lock-in amplifier, each sensing unit is by optical fiber cascade and be distributed in a certain region, the laser that lasing light emitter exports transfers to first order sensing unit through distribution type fiber-optic, the shoot laser of first order sensing unit enters second level sensing unit as incident light, by that analogy, realize utilizing the tandem type of laser energy with this, the detection signal that each sensing unit exports is sent to lock-in amplifier, the output of lock-in amplifier is connected with control terminal, the detection signal of control terminal to input shows and reports to the police.
Described sensing unit is made up of detecting unit and amplifier, described detecting unit is based on quartz tuning fork strengthened photoacoustic spectrum gas detect structure, by tuning fork vibration, gas photoacoustic signal is converted to electric signal to export, amplifier realizes electric signal and collects, amplifies and transmission.
Described detecting unit comprises a quartz tuning-fork, pair of alignment lens, a pair convergent lens, a pair space optical coupling device and a pair resonantron, through distribution type fiber-optic import incident light through space optical coupling device, the Gauss light of collimation focusing is become after collimation lens and convergent lens, this Gauss light is through outgoing after resonantron, shoot laser is through convergent lens, collimation lens and space optical coupling device to be introduced in optical fiber and are become the incident light of next stage sensing unit, orthogonally with resonantron between two resonantrons be placed with quartz tuning-fork, this place's gas can absorb the laser of specific wavelength and excite sound waves signal, sound wave resonance detected by quartz tuning-fork and be converted to electric signal and reach amplifier between resonantron, amplifier carries out filtering to electric signal, lock-in amplifier is sent to after amplification.
Described lasing light emitter is tunable distributed feedback laser, has narrowband wavelength laser output characteristic, its Wavelength tunable.
Described a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser, it also comprises Laser control unit, Laser control unit is connected with the tuning control port of lasing light emitter, and Laser control unit is controlled by temperature or the mode of Current Control realizes the control of optical maser wavelength and tuning.
Described a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser, it also comprises modulation signal generation unit, and the AC signal that modulation signal generation unit produces certain frequency is modulated by the drive current of Laser control unit to lasing light emitter.
Described control terminal comprises delay circuit, signal display unit and alarm unit.
The invention has the beneficial effects as follows: the present invention utilizes single light source, by each sensor unit of distribution type fiber-optic cascade, shoot laser is carried out multistage multiplexing, feasible region multiple spot distribution type fiber-optic gas-monitoring, and be positioned at the mode receiver gases photoacoustic signal of gas sensor by tuning fork-gas resonance of each point, realize monitoring the distributed gas in a certain region and reporting to the police by control terminal, there is the monitoring of areal distribution formula multiple spot, the utilization of energy of light source multi-stage, efficient, high s/n ratio, detection module to the advantage of neighbourhood noise immunity.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser of the present invention;
Fig. 2 is the present invention's quartz tuning fork strengthened optoacoustic spectroscopy gas detection cell principle schematic;
Fig. 3 is control terminal operating diagram of the present invention;
In figure, 1-is tunable distributed feedback laser, 2-Laser control unit, 3-modulation signal generation unit, 4-distribution type fiber-optic, 5-sensing unit, 6-lock-in amplifier, 7-control terminal, 51-detecting unit, 52-signal amplifier, 512-optical fiber-space optical coupling device, 513-collimation lens, 514-convergent lens, 515-resonantron, 516-quartz tuning-fork, 61-is with reference to (modulation) signal, 71-delay circuit, 72-signal display unit, 73-alarm unit.
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail, but protection scope of the present invention is not limited to the following stated.
As shown in Figure 1, a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser, it comprises lasing light emitter 1, multiple sensing unit 5 and lock-in amplifier 6, it also comprises Laser control unit 2, Laser control unit 2 is connected with the tuning control port of lasing light emitter 1, and Laser control unit 2 is controlled by temperature or the mode of Current Control realizes the control of optical maser wavelength and tuning; It also comprises modulation signal generation unit 3, and the AC signal that modulation signal generation unit 3 produces certain frequency is modulated by the drive current of Laser control unit 2 pairs of lasing light emitters 1; Each sensing unit 5 is by optical fiber cascade and be distributed in a certain region, the laser that lasing light emitter 1 exports transfers to first order sensing unit 5 through distribution type fiber-optic 4, the shoot laser of first order sensing unit 5 enters second level sensing unit 5 as incident light, by that analogy, realize utilizing the tandem type of laser energy with this, the detection signal that each sensing unit 5 exports is sent to lock-in amplifier 6, the output of lock-in amplifier 6 is connected with control terminal 7, and the detection signal of control terminal 7 to input shows and report to the police.
Wherein lasing light emitter 1 is tunable distributed feedback laser, has narrowband wavelength laser output characteristic, its Wavelength tunable.
Described sensing unit 5 is made up of detecting unit 51 and amplifier 52, described detecting unit 51 is based on quartz tuning fork strengthened photoacoustic spectrum gas detect structure, by tuning fork vibration, gas photoacoustic signal is converted to electric signal to export, amplifier realizes electric signal and collects, amplifies and transmission.
As shown in Figure 2, described detecting unit 51 comprises a quartz tuning-fork 516, pair of alignment lens 513, a pair convergent lens 514, a pair space optical coupling device 512 and a pair resonantron 515, through distribution type fiber-optic 4 import incident light through space optical coupling device 512, the Gauss light of collimation focusing is become after collimation lens 513 and convergent lens 514, this Gauss light is through outgoing after resonantron 515, shoot laser is through convergent lens 514, collimation lens 513 and space optical coupling device 512 to be introduced in optical fiber and are become the incident light of next stage sensing unit 51, orthogonally with resonantron 515 between two resonantrons 515 be placed with quartz tuning-fork 516, this place's gas can absorb the laser of specific wavelength and excite sound waves signal, sound wave resonance detected by quartz tuning-fork 516 and be converted to electric signal and reach amplifier 52 between resonantron 515, amplifier 52 pairs of electric signal carry out filtering, lock-in amplifier 6 is sent to after amplification.
As shown in Figure 3, described control terminal 7 comprises delay circuit 71, signal display unit 72 and alarm unit 73.
Tunable distribution type laser device 1 is sent to lock-in amplifier 6 with reference to modulation signal 61, lock-in amplifier 6 carries out time delay step by step to the photoacoustic signal data that each amplifier 52 transmits by the delay circuit 71 of control terminal 7 and reads, and show at the signal display unit 72 of control terminal 7, as survey gas concentration and exceed safety standard, the alarm unit 73 of control terminal 7 is reported to the police.
Claims (7)
1. the quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser, it is characterized in that: it comprises lasing light emitter (1), multiple sensing unit (5) and lock-in amplifier (6), each sensing unit (5) is by optical fiber cascade and be distributed in a certain region, the laser that lasing light emitter (1) exports transfers to first order sensing unit (5) through distribution type fiber-optic (4), the shoot laser of first order sensing unit (5) enters second level sensing unit (5) as incident light, by that analogy, realize utilizing the tandem type of laser energy with this, the detection signal that each sensing unit (5) exports is sent to lock-in amplifier (6), the output of lock-in amplifier (6) is connected with control terminal (7), the detection signal of control terminal (7) to input shows and reports to the police.
2. a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser according to claim 1, it is characterized in that: described sensing unit (5) is made up of detecting unit (51) and amplifier (52), described detecting unit (51) is based on quartz tuning fork strengthened photoacoustic spectrum gas detect structure, by tuning fork vibration, gas photoacoustic signal is converted to electric signal to export, amplifier realizes electric signal and collects, amplifies and transmission.
3. a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser according to claim 2, it is characterized in that: described detecting unit (51) comprises a quartz tuning-fork (516), pair of alignment lens (513), a pair convergent lens (514), a pair space optical coupling device (512) and a pair resonantron (515), the incident light imported through distribution type fiber-optic (4) is through space optical coupling device (512), the Gauss light of collimation focusing is become after collimation lens (513) and convergent lens (514), this Gauss light is through resonantron (515) outgoing afterwards, shoot laser is through convergent lens (514), collimation lens (513) and space optical coupling device (512) to be introduced in optical fiber and are become the incident light of next stage sensing unit (51), orthogonally with resonantron (515) between two resonantrons (515) be placed with quartz tuning-fork (516), this place's gas can absorb the laser of specific wavelength and excite sound waves signal, sound wave resonance detected by quartz tuning-fork (516) and be converted to electric signal and reach amplifier (52) between resonantron (515), amplifier (52) carries out filtering to electric signal, lock-in amplifier (6) is sent to after amplification.
4. a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser according to claim 1, it is characterized in that: described lasing light emitter (1) is tunable distributed feedback laser, there is narrowband wavelength laser output characteristic, its Wavelength tunable.
5. a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser according to claim 1, it is characterized in that: it also comprises Laser control unit (2), Laser control unit (2) is connected with the tuning control port of lasing light emitter (1), and Laser control unit (2) is controlled by temperature or the mode of Current Control realizes the control of optical maser wavelength and tuning.
6. a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser according to claim 1, it is characterized in that: it also comprises modulation signal generation unit (3), the AC signal that modulation signal generation unit (3) produces certain frequency is modulated by the drive current of Laser control unit (2) to lasing light emitter (1).
7. a kind of quartz tuning fork strengthened optoacoustic spectroscopy distribution type fiber-optic gas sensor based on tunable laser according to claim 1, is characterized in that: described control terminal (7) comprises delay circuit (71), signal display unit (72) and alarm unit (73).
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| CN108732105A (en) * | 2018-07-10 | 2018-11-02 | 南昌航空大学 | Distributed gas detection device based on fast travelling waves of optical fibre and method |
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| CN112504433A (en) * | 2020-12-18 | 2021-03-16 | 西北大学 | Temperature self-reference sensitivity tunable optical fiber distributed vibration detection device and method |
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| CN108732105A (en) * | 2018-07-10 | 2018-11-02 | 南昌航空大学 | Distributed gas detection device based on fast travelling waves of optical fibre and method |
| CN112147076A (en) * | 2020-08-21 | 2020-12-29 | 西安电子科技大学 | Absorption optical path enhanced double-resonance photoacoustic spectrum trace gas detection system |
| CN112504433A (en) * | 2020-12-18 | 2021-03-16 | 西北大学 | Temperature self-reference sensitivity tunable optical fiber distributed vibration detection device and method |
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