CN103148895B - The distributing optical fiber sensing method of random code external modulation and device - Google Patents
The distributing optical fiber sensing method of random code external modulation and device Download PDFInfo
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Abstract
A kind of distributing optical fiber sensing method of random code external modulation, comprise the following steps: the continuous laser a branch of live width being less than or equal to 100kHz is divided into two-way light after transfering to other localities and being made as random code laser, one tunnel is as reference light, and sensor fibre is incided as detection light in another road; Adopt cross-correlation method to process after backward scattered for sensor fibre Brillouin scattering and reference light are converted to electric signal, obtain comprising the information of temperature variation in testing fiber and stress distribution.A distribution type optical fiber sensing equipment for random code external modulation, comprises laser beam emitting device and is positioned at light part flow arrangement, detection optical fiber device, photoelectric conversion device and the signal acquisition process display device on laser beam emitting device emitting light path.The invention solves positioning precision and temperature, contradiction between strain measurement precision that current distributed fiberoptic sensor exists, long distance, high-resolution temperature and strain measurement can be realized.
Description
Technical field
The present invention relates to Fibre Optical Sensor, be specially a kind of distributing optical fiber sensing method and device of random code external modulation.
Background technology
Distributed fiberoptic sensor is a kind of sensing type Fibre Optical Sensor, it have to obtain in sensor fibre region simultaneously in time with the ability of the measured distributed intelligence of spatial variations.Can be used for carrying out sensor measuring to the information such as strain, temperature of building (as dam, building), detection optical fiber used in detection is laid in building in advance.This sensor is divided into fl transmission type and reflection-type.Fl transmission type is the effect utilizing external physical quantity, make, between optical fiber two transmission mode, Energy Coupling occurs, feature is that output terminal is measured coupled modes, frequency in its optical spectrum characteristic reflects Coupling point event, as: temperature, strain, amplitude reflects the measured size in this position.Reflection-type is that the dynamic change of the back-scattering light that the effect such as Rayleigh scattering, Raman scattering, Brillouin scattering utilizing optical fiber to produce under outside perturbation action produces is measured.Be characterized in adopting optical time domain reflection technology to the location of the measurement and space of carrying out scattered light size in incidence end.
What the Fibre Optical Sensor of fl transmission type adopted is inject continuous light and pulsed light respectively from the both sides of optical fiber, there is certain difference in the light frequency of this two paths of signals, the light frequency of any signal in both adjustments, just there will be Image magnify effect when both light frequency differences are equal with the frequency shift amount that Brillouin or the Raman scattering in somewhere in optical fiber cause, the echoed signal of pulse can carry the response message of this event.But the place that this technology is not enough at present needs form bidirectional optical path and operate at sensor fibre two ends, cause this system optical member Numerous and complex structure cost is higher, in the practical application that long distance detects, have inconvenience, just progressively the Fibre Optical Sensor of reflection type replaced.
What the Fibre Optical Sensor of reflection-type utilized is optical time domain reflection technology, utilizes the Raman scattering of optical fiber itself or brillouin scattering signal to carry out sensing in this technology.By optical fiber one end input detection light, there is Raman scattering and Brillouin scattering in a fiber in detection light, the anti-stokes light that Raman diffused light can be divided into wavelength to be greater than the stokes light of incident light and wavelength being less than incident light at frequency domain, the Strength Changes amount of stokes light is only relevant with the absolute temperature of this point to have nothing to do with other conditions, therefore can utilize the temperature variation that this feature is come in measuring optical fiber.Brillouin scattering is divided into spontaneous brillouin scattering and stimulated Brillouin scattering.Spontaneous brillouin scattering refers to that atom, molecule or the ion under normal temperature state in optical fiber is made continuous elastic mechanics because of spontaneous heating campaign and vibrated, define the Self-sounding wave field in optical fiber, the density that acoustic vibration along optical fiber direction makes optical fiber in time with space periodicity change, thus make refractive index on optical fiber by periodic modulation.This spontaneous sound wave is counted as the grating along fibre movement.When laser is injected in optical fiber, " diffraction " effect of " grating " will be subject to, produce spontaneous brillouin scattering light.Stimulated Brillouin scattering refers to when the incident optical power entering optical fiber exceedes a certain threshold value, the electrostrictive effect produced in optical fiber, make to produce cyclic deformation or elastic vibration along optical fiber, namely relevant sound wave is created in optical fiber, this sound wave makes optical fibre refractivity by periodic modulation along its direction of propagation, thus define a refractive-index grating moved with this velocity of sound, incident light is made to produce scattering, scattered light frequency moves down, when meeting wavefield phase coupling, acoustic wavefield is greatly strengthened, thus make the enhancing of the electrostriction acoustic wavefield in optical fiber and corresponding scattered light wave field be greater than their respective losses, the relevant amplification of acoustic wavefield and scattered optical field will be there is, thus cause most of incident light to be converted into rear orientation light, produce stimulated Brillouin scattering (SBS) process.The light that Brillouin scattering occurs can produce the change of frequency displacement and power, the temperature of frequency shift amount and power variation and inside of optical fibre and Strain Distribution also exist the relation determined, by the frequency shift amount of Brillouin scattering and the variable quantity of power of case point each in measuring optical fiber, just can obtain the distributed intelligence of temperature in optical fiber and strain, be reflected in and macroscopically can know the temperature of the buildings that optical fiber detects and the information of Strain Distribution exactly.
The LASER Light Source major part that existing distributed optical time domain reflection optical fiber sensing technology uses is pulse type laser, and for pulse type laser, receiving end response accuracy requires high on the one hand, signal capture difficulty; On the other hand positioning precision and pulsewidth are inversely proportional to, if narrow to improve precision the precision that pulsewidth can cause scattared energy deficiency and then affect temperature and strain measurement, cause positioning precision and the contradiction between temperature and strain measurement precision.Current distributed its measuring accuracy of optical time domain reflection optical fiber sensing system based on pulse type laser, all more than 1 meter, is difficult to meet high-resolution requirement.In addition, the method that tradition extracts frequency shift amount and power variation information is optical heterodyne, the laser being about to occur Brillouin scattering dorsad in optical fiber adopts light heterodyne method to obtain frequency shift amount and power variation, because polarization state is very large on optical heterodyne impact, also need to adopt some polarizations regulating difficulty to maintain device, as polarization maintaining optical fibre, various wave plates etc. improve the detection accuracy of temperature and strain, make whole apparatus structure complicated, operate also more loaded down with trivial details.
Minority adopts continuous light as the reflective distributed sensor system of light source, as BOCDR, is directly carry out internal modulation to laser instrument, realizes the fibre scattering spectrometry of location by controlling modulation parameter.This technology can realize the high resolving power of centimetres, but fiber lengths distance shorter (current technology is no more than 500 meters) that can measure, the high precision distributed sensing being difficult to realize long distance is measured.
Summary of the invention
The present invention solves positioning precision that current distributed fiberoptic sensor exists and contradiction and the comparatively complicated technical matters of structure between temperature and strain measurement precision, provides a kind of distributing optical fiber sensing method and device of random code external modulation.
The distributing optical fiber sensing method of random code external modulation of the present invention realizes by the following technical solutions: a kind of distributing optical fiber sensing method of random code external modulation, comprise the following steps: a branch of continuous type laser is divided into two-way light by (a) after random code signal external modulation, one tunnel is as reference light, and another road is as detection light; B detection light is inputed to detection optical fiber by (), carry out filtering to the laser that backward Brillouin scattering occurs in detection optical fiber; C the detection light of filtered different wave length is converted to corresponding electric signal by () one by one, and be also converted to corresponding electric signal with reference to light; D the electric signal of two-way light adopts cross-correlation method to process by (), obtain the relation information of the frequency shift amount of the backward Brillouin scattering light in detection optical fiber, power variation and position, again this information is analyzed, obtain temperature and position in detection optical fiber and strain and the relation information of position.Wherein, the centre frequency of frequency shift amount set by adjustable light wave-filter of Brillouin scattering is demarcated, and its power variation is demarcated by the peak value size of cross-correlated signal, and its positional information is then demarcated by the time delay of cross-correlated signal.
The distribution type optical fiber sensing equipment of random code external modulation of the present invention realizes by the following technical solutions: a kind of distribution type optical fiber sensing equipment of random code external modulation, comprises laser beam emitting device and is positioned at the light part flow arrangement with two exit ends on laser beam emitting device emitting light path; First exit end of light part flow arrangement is connected with circulator; First exit end of described smooth part flow arrangement is connected with the input port of circulator, and the output port of circulator is connected with image intensifer, adjustable light wave-filter and the second photodetector in turn by optical fiber; Second exit end of light part flow arrangement has the first photodetector by Fiber connection; First photodetector is all connected same signal processing system with the output terminal of the second photodetector; Signal processing system is connected with display device.The random light signal code that laser beam emitting device sends is divided into detection light and reference light two-way by light part flow arrangement, wherein detect light and incide sensor measuring optical fiber via circulator, and brillouin scattering signal is produced in sensor measuring optical fiber, the frequency of this brillouin scattering signal and intensity carry temperature and the strain information of sensor measuring optical fiber.By the centre frequency arranging adjustable light wave-filter, the brillouin scattering signal of different capacity and frequency shift amount is converted to electric signal, and the electric signal that this electric signal and reference light are changed is carried out cross correlation process in signal processing system, demarcate the relation information of the frequency shift amount of Brillouin scattering, power variation and position, obtain the brillouin gain spectrum of diverse location, and shown by the relation of display device by temperature in sensor measuring optical fiber and strain and position.Described cross-correlation method is the common method of those skilled in the art; Signal processing system adopts cross-correlation method to process the signal collected under the support of corresponding software, and described software is that those skilled in the art easily write.
Further, described laser beam emitting device comprises laser instrument and the Polarization Controller be positioned in turn in laser emitting light path and electrooptical modulation module; Also comprise random code source; The voltage output end in described random code source is connected with the voltage signal inputs of electrooptical modulation module; The exit end of electrooptical modulation module is connected by the input end of optical fiber with light part flow arrangement; Laser instrument adopts live width to be less than or equal to the C-band narrow line width regulatable laser of 100kHz or narrow linewidth semiconductor laser or narrow cable and wide optical fiber laser.The continuous light that this laser instrument exports, after being loaded with the electrooptic modulator of random code modulation, becomes the random light signal code of intensity fluctuation.
Laser signal after the modulation of the present invention random code source used, its intensity random fluctuation, has the advantages that bandwidth is high, correlativity is good, high as locating information measuring accuracy, antijamming capability is strong, dynamic range is large, is desirable distance measurement signals.The technology of the present invention method overcomes the location high precision and temperature and the contradiction that strain between high-acruracy survey that conventional pulsed sensing technology exists, and realizes locating high precision and temperature and strain measurement high precision simultaneously.The high coherence of laser can effectively reduce the power realizing Brillouin scattering, through a large amount of experiments, we find to adopt laser linewidth to be less than or equal to the laser of 100kHz, the minimum power realized needed for Fibre Optical Sensor can be effectively reduced, compared to existing BOCDR internal modulation spectrum widening frequency sweeping method, the present invention can improve sensor fibre distance greatly.The method of the invention adopts cross-correlation method to extract metrical information, and avoiding light heterodyne method needs to introduce the comparatively complicated polarization retainer member of operation, increases the problem of cost while causing system complex; The device extracted for detecting light signal is only adjustable light wave-filter and photodetector, and it is succinct that hardware forms simple operations, effectively reduces equipment cost.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention.
1-laser instrument, 2-random code source, 3-Polarization Controller, 4-electrooptical modulation module, 5-light part flow arrangement, 6-circulator, 7-detection optical fiber, 8-adjustable light wave-filter, 9-first photodetector, 10-second photodetector, 11-signal processing system, 12-display device, 13-image intensifer.
Embodiment
A distributing optical fiber sensing method for random code external modulation, comprises the following steps: a branch of continuous type laser is divided into two-way light by (a) after random code signal external modulation, and a road is as reference light, and another road is as detection light; B detection light is inputed to detection optical fiber by (), carry out filtering to the laser that backward Brillouin scattering occurs in detection optical fiber; C the detection light of filtered different wave length is converted to corresponding electric signal by () one by one, and be also converted to corresponding electric signal with reference to light; D the electric signal of two-way light adopts cross-correlation method to process by (), obtain the relation information of the frequency shift amount of the backward Brillouin scattering light in detection optical fiber, power variation and position, again this information is analyzed, obtain temperature and position in detection optical fiber and strain and the relation information of position.
A distribution type optical fiber sensing equipment for random code external modulation, comprises laser beam emitting device and is positioned at the light part flow arrangement 5 with two exit ends on laser beam emitting device emitting light path; First exit end of light part flow arrangement 5 is connected with circulator 6; First exit end of described smooth part flow arrangement 5 is connected with the input port of circulator 6, and the output port of circulator 6 is connected with image intensifer 13, adjustable light wave-filter 8 and the second photodetector 10 in turn by optical fiber; Second exit end of light part flow arrangement 5 has the first photodetector 9 by Fiber connection; First photodetector 9 is all connected same signal processing system 11 with the output terminal of the second photodetector 10; Signal processing system 11 is connected with display device 12.
Described laser beam emitting device comprises laser instrument 1 and the Polarization Controller 3 that is positioned in turn on laser instrument 1 emitting light path and electrooptical modulation module 4; Also comprise random code source 2; The voltage output end in described random code source 2 is connected with the voltage signal inputs of electrooptical modulation module 4; The exit end of electrooptical modulation module 4 is connected by the input end of optical fiber with light part flow arrangement 5; Laser instrument 1 adopts live width to be less than or equal to the C-band narrow line width regulatable laser of 100kHz or narrow linewidth semiconductor laser or narrow cable and wide optical fiber laser.
As shown in Figure 1, the intensity that sends of laser beam emitting device incides the left side entry port of light part flow arrangement 5 through the laser beam of random code signal madulation; Right side first exit end of light part flow arrangement 5 connects the left side input port of circulator 6, and the right side reflector port of circulator 6 connects sensor measuring optical fiber 7, and sensor measuring optical fiber 7 used is general single mode fiber G652 series, and length is 10km-100km; The lower output mouth of circulator 6 connects image intensifer 13, adjustable light wave-filter 8 and the second photodetector 10 in turn by optical fiber.Right side second exit end of light part flow arrangement 5 is by Fiber connection first photodetector 9.The output terminal of the first photodetector 9 and the second photodetector 10 divides the right side being clipped to connection signal disposal system 11 upper and lower input port.On the left of signal processing system 11, output port connects display device 12.Signal processing system 11 adopts cross-correlation method to process to the two path signal received, obtain the relation information of the frequency shift amount of the Brillouin scattering in detection optical fiber, power variation and position, again this information is analyzed, obtain temperature and position in detection optical fiber and strain and the relation information of position, and being shown by display device 12.
Claims (3)
1. a distributing optical fiber sensing method for random code external modulation, is characterized in that, comprise the following steps: a branch of continuous type laser is divided into two-way light by (a) after random code signal external modulation, and a road is as reference light, and another road is as detection light; B detection light is inputed to detection optical fiber by (), carry out filtering to the laser that backward Brillouin scattering occurs in detection optical fiber; C the detection light of filtered different wave length is converted to corresponding electric signal by () one by one, and be also converted to corresponding electric signal with reference to light; D the electric signal of two-way light adopts cross-correlation method to process by (), obtain the relation information of the frequency shift amount of the backward Brillouin scattering light in detection optical fiber, power variation and position, again this information is analyzed, obtain temperature and position in detection optical fiber and strain and the relation information of position.
2. the distribution type optical fiber sensing equipment of a random code external modulation, for realizing the distributing optical fiber sensing method of random code external modulation as claimed in claim 1, it is characterized in that the light part flow arrangement (5) with two exit ends comprising laser beam emitting device and be positioned on laser beam emitting device emitting light path; First exit end of light part flow arrangement (5) is connected with circulator (6); First exit end of described smooth part flow arrangement (5) is connected with the input port of circulator (6), and the reflector port of circulator (6) is connected with sensor measuring optical fiber (7); The output port of circulator (6) is connected with image intensifer (13), adjustable light wave-filter (8) and the second photodetector (10) in turn by optical fiber; Second exit end of light part flow arrangement (5) has the first photodetector (9) by Fiber connection; First photodetector (9) is all connected same signal processing system (11) with the output terminal of the second photodetector (10); Signal processing system (11) is connected with display device (12).
3. the distribution type optical fiber sensing equipment of random code external modulation as claimed in claim 2, it is characterized in that, described laser beam emitting device comprises laser instrument (1) and the Polarization Controller (3) that is positioned in turn on laser instrument (1) emitting light path and electrooptical modulation module (4); Also comprise random code source (2); The voltage output end of described random code source (2) is connected with the voltage signal inputs of electrooptical modulation module (4); The exit end of electrooptical modulation module (4) is connected by the input end of optical fiber with light part flow arrangement (5); Laser instrument (1) adopts live width to be less than or equal to the C-band narrow line width regulatable laser of 100kHz or narrow linewidth semiconductor laser or narrow cable and wide optical fiber laser.
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| CN105091919B (en) * | 2015-05-26 | 2017-07-14 | 中国科学院上海光学精密机械研究所 | The double optical fiber cable sensors of high sensitivity |
| CN107543567B (en) * | 2017-08-11 | 2019-10-08 | 太原理工大学 | BOCDA distribution type optical fiber sensing equipment and method based on the modulation of physical accidental code |
| CN109084830B (en) * | 2018-06-25 | 2020-08-21 | 太原理工大学 | Optical fiber multi-parameter detection system and method for goaf traffic infrastructure |
| CN113758509B (en) * | 2021-09-09 | 2024-02-06 | 太原理工大学 | Temperature, strain and vibration integrated optical fiber sensing device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101226100A (en) * | 2008-01-31 | 2008-07-23 | 太原理工大学 | Chaos light time domain reflectometer and measuring method thereof |
| CN102176020A (en) * | 2010-12-30 | 2011-09-07 | 太原理工大学 | Chaos Laser ranging device based on liquid crystal |
| CN102322806A (en) * | 2011-08-01 | 2012-01-18 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer relevant to chaotic laser |
| KR101182650B1 (en) * | 2010-10-19 | 2012-09-14 | 한국과학기술연구원 | Distributed optical fiber sensor and sensing method using bbrillouin scattering |
| CN102928832A (en) * | 2012-11-30 | 2013-02-13 | 中国科学院上海光学精密机械研究所 | Remote laser distance measuring system based on high-speed pseudo-random code modulation and photon counting |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3829602B2 (en) * | 2000-08-23 | 2006-10-04 | 日本電気株式会社 | Encryption key distribution device |
| CN102607621A (en) * | 2012-03-29 | 2012-07-25 | 中国科学院上海光学精密机械研究所 | Distributed optical fiber Brillouin sensing device and method thereof for detecting temperature and strain synchronously |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101226100A (en) * | 2008-01-31 | 2008-07-23 | 太原理工大学 | Chaos light time domain reflectometer and measuring method thereof |
| KR101182650B1 (en) * | 2010-10-19 | 2012-09-14 | 한국과학기술연구원 | Distributed optical fiber sensor and sensing method using bbrillouin scattering |
| CN102176020A (en) * | 2010-12-30 | 2011-09-07 | 太原理工大学 | Chaos Laser ranging device based on liquid crystal |
| CN102322806A (en) * | 2011-08-01 | 2012-01-18 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer relevant to chaotic laser |
| CN102928832A (en) * | 2012-11-30 | 2013-02-13 | 中国科学院上海光学精密机械研究所 | Remote laser distance measuring system based on high-speed pseudo-random code modulation and photon counting |
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