CN202533198U - Distributed fiber Brillouinstrain strain and temperature sensor - Google Patents

Distributed fiber Brillouinstrain strain and temperature sensor Download PDF

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CN202533198U
CN202533198U CN2012201153284U CN201220115328U CN202533198U CN 202533198 U CN202533198 U CN 202533198U CN 2012201153284 U CN2012201153284 U CN 2012201153284U CN 201220115328 U CN201220115328 U CN 201220115328U CN 202533198 U CN202533198 U CN 202533198U
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王一华
许季青
黄凡
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HUBEI QINGYU TECHNOLOGY Co Ltd
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Abstract

The utility model relates to a distributed fiber Brillouinstrain strain and temperature sensor, wherein, in structure, a PID controller is connected with a computer and two current controllers respectively, the two current controllers are respectively connected with the detection laser and the input end of a pump laser, the detection laser is orderly connected with a 95:5 fiber coupler, an Er-doped fiber amplifier, a filter, a polarizer, an electrooptic modulator, a polarization scrambler, an annular device, a fiber, a photoelectric detector, a data collection card and a computer 18, the computer is connected with the pulse generator, the pulse generator is connected with the electrooptic modulator, the pump laser is orderly connected with another 95:5 fiber coupler, an isolator, a detection fiber and the public end of the annular device, a 50:50 fiber coupler is connected between the two 95:5 fiber couplers, the 50:50 fiber coupler is connected with the data collection card through anther one photoelectric detector. The distributed fiber Brillouinstrain strain and temperature sensor employs two distributed feedback type lasers to generate a spatial resolution superior to one meter, thereby greatly reducing the cost of the sensor.

Description

Distribution type fiber-optic Brillouin strain and temperature sensor
Technical field
The utility model relates to distribution type fiber-optic Brillouin strain and temperature sensor, belongs to the distributed fiberoptic sensor technical field.
Background technology
Optical fiber itself is not charged, anti-electromagnetism, radiation hardness, high voltage withstanding, do not produce characteristics such as electric spark and insulating property are good, make optical fiber sensing system will become the main flow of sensing system, and progressively substitute traditional sensing system.Physical quantity on the optical fiber such as: when pressure, temperature, humidity, electric field, magnetic field etc. change, can cause that the physical characteristics of optical fiber changes, thereby make the light wave that conducts in the optical fiber produce various optical effects, change or the like like: scattering, polarization, intensity.Through the variation of light wave in the detection fiber, realize detection to physical quantitys such as temperature, pressure, deformation, water levels.In recent years detection of the fast development of optoelectronic device, particularly semiconductor laser, wavelength-division multiplex and optical coupling technology, photosignal and the technological development of processing or the like, making optical fiber be used for doing the distributed sensor system becomes reality.
The configuration state monitoring can be found out the early stage problem sign of structure, and infringement is repaired in the prevention infringement.It also can instruct and use new building materials, can satisfy the needs of long-term maintaining structure.At present, the sensor that is used for configuration state monitoring only provides the stress information of local influence structure.Its localized character provides incomplete building health and fitness information.They can't find early stage defective, and like crack or flexing, this needs the centimetre-sized spatial resolution.We need to detect, assess integrally-built destructiveness.Such sensor must provide distributed temperature and strain measurement in surpassing tens meters to tens kilometers.
Distribution type fiber-optic Brillouin strain and temperature sensor are measured strain and temperature information in very long distance; Be an outstanding large scale structure health monitoring instrument, be applicable to like pipeline, distribution line, dam, security system, national defence equipment, bridge and detection etc.This sensor relies on huge distribution scale and the high resolving power remote monitoring is provided aspect optical communication.Have no other technologies to compare with its cost.
Also has a kind of common optical fiber sensing technology that is applicable to the localization measurement: fiber-optic grating sensor.Yet,, when potential damage or leak position the unknown, be difficult to confirm in advance the place that fiber-optic grating sensor or strainometer are placed for the configuration state monitoring.When the specific region was known, fiber-optic grating sensor can be used as the sensor of a localization.
The measuring method of strain of existing distributed optical fiber Brillouin and temperature sensor is to utilize the stimulated Brillouin scattering phenomenon.Existing sensors needs two rightabout laser instruments through same fiber optic loop.One is continuous wave laser, and another is a pulsed laser.The nonlinear interaction of sound wave in the laser of incident optical and the optical fiber; Light wave produces sound wave through electrostriction; Cause the periodic modulation (refractive-index grating) of optical fibre refractivity, produce the Brillouin scattering that frequency moves down, the frequency displacement V of the Brillouin scattering dorsad that in optical fiber, produces BFor:
V B=2nv/λ(1)
Wherein n for lambda1-wavelength λ place refractive index, v is the velocity of sound in the optical fiber.
Brillouin scattering optical frequency shift in optical fiber has strain and temperature effect V BHave strain and temperature effect
Figure BDA0000146745090000021
The frequency displacement of Brillouin scattering
δν B=C +C vTδT (3)
The coefficient of strain C of frequency displacement wherein V6With temperature coefficient C VTFor
C =0.0482±0.004MHz/με,C vT=1.10±0.02MHz/K
The strength ratio of Brillouin scattering relies on the strain and the temperature of optical fiber in the optical fiber
100 δI B I B = C Pϵ δϵ + C PT δT - - - ( 4 )
The coefficient of strain C of strength ratio wherein P εWith temperature coefficient C PTFor
C =-(7.7±1.4)×10 4%C PT=0.36±0.06%/K
By (3), (4) formula, as long as measure strain δ ε and the temperature difference δ T that each section frequency displacement and strength ratio on the optical fiber can demodulate this section optical fiber.
There are two kinds of Brillouin fiber optic optical sensors at present.Brillouin scattering otdr measurement technology (BOTDR) energy measurement is based on the strain and the temperature of Brillouin scattering monopulse.Brillouin optical time domain analysis system (BOTDA) uses more complex phenomena, that is: a stimulated Brillouin scattering (SBS).Stokes scattering (comprising Brillouin scattering and Raman scattering).Because a little less than Brillouin's signal, the measurement range of BOTDR is limited, signal to noise ratio (S/N ratio) is generally poor than the BOTDA technology.One of technical advantage of BOTDR: have only an end optical fiber to need visit.The BOTDA technology is more powerful.Because signal intensity is big, strain and temperature survey are more accurate, and measurement range is the technology of being longer than BOTDR usually.Half the except the contraction in length that two-sided visit causes, the BOTDA method needs more optical element and two-way light path.Therefore, preferably use the sensing system based on BOTDA, it can provide high precision and the method for measuring strain temperature fast.
Summary of the invention
The purpose that the utility model relates to provides a kind of distribution type fiber-optic Brillouin strain and temperature sensor based on BOTDA; The utility model uses two distributed feed-back formula laser instruments as pump laser and detecting laser; This distributed sensor based on distributed feed-back formula laser instrument has solved the deficiency of system before, can produce to be superior to 1 meter spatial resolution.Use distributed feed-back formula laser instrument to replace frequency stabilization and tunable laser system, thereby significantly reduce the cost of sensing system.
The technical scheme of the utility model is:
Distribution type fiber-optic Brillouin strain and temperature sensor; Comprise detecting laser, pump laser, detection optical fiber, two 95: 5 fiber couplers, 50: 50 fiber couplers, two photodetectors, Erbium-Doped Fiber Amplifier (EDFA), wave filter, data collecting card, PID controller, two current controllers, the polarizer, scrambler, pulse producer, electrooptic modulator, circulator, isolator and computing machines; It is characterized in that: the input end of PID controller links to each other with computing machine; The output terminal of PID controller links to each other with the input end of two current controllers respectively; The output terminal of two current controllers links to each other with the input end of detecting laser, pump laser respectively; The output terminal of detecting laser links to each other with the input end of 95: 5 fiber coupler, and an output terminal of this 95: 5 fiber couplers links to each other with the input end of Erbium-Doped Fiber Amplifier (EDFA), and another output terminal of this 95: 5 fiber couplers links to each other with an input end of 50: 50 fiber couplers; The output terminal of Erbium-Doped Fiber Amplifier (EDFA) links to each other with the input end of wave filter; The output terminal of wave filter links to each other with the input end of the polarizer, and the input end of pulse producer links to each other with computing machine, and the output terminal of pulse producer links to each other with an input end of electrooptic modulator; The output terminal of the polarizer links to each other with another input end of electrooptic modulator; The output terminal of electrooptic modulator links to each other with the input end of scrambler, and the output terminal of scrambler links to each other with the input end of circulator, and the common port of circulator links to each other with detection optical fiber; The output terminal of circulator links to each other with the input end of a photodetector, and the output terminal of this photodetector links to each other with computing machine with data collecting card successively; The output terminal of pump laser links to each other with the input end of another 95: 5 coupling mechanisms; An output terminal of another 95: 5 fiber couplers links to each other with the input end of isolator; The output terminal of isolator links to each other with detection optical fiber; Another output terminal of another 95: 5 fiber couplers links to each other with another input end of 50: 50 fiber couplers; The output terminal of 50: 50 fiber couplers links to each other with the input end of another photodetector, and the output terminal of another photodetector links to each other with computing machine with data collecting card successively.
The PID controller is the abbreviation of proportional-integral derivative controller.
Described detecting laser, pump laser are distributed feed-back formula laser instrument.
Distribution type fiber-optic Brillouin strain and temperature sensor use two distributed feed-back formula laser instruments.A distributed feed-back formula laser instrument is as pump laser, and current controller Control current source and temperature are used for stablizing the temperature of distributed feed-back formula laser instrument.Separated by 95: 5 fiber couplers from the light beam of distributed feed-back formula laser instrument output, percent Five Classics 50: 50 fiber couplers, photodetectors of sending light beam are sent to data collecting card; 95% light is transferred to measuring fiber then through an isolator output.
Another distributed feed-back formula laser instrument is as detecting laser; Wavelength is 1550nm, and current controller Control current source and temperature are used for stablizing the temperature of distributed feed-back formula laser instrument; Separated by 95: 5 fiber couplers from the light beam of distributed feed-back formula laser instrument output; Percent Five Classics 50: 50 fiber couplers, photodetectors of sending light beam are sent to data collecting card, and all the other output light of 95% are amplified by Erbium-Doped Fiber Amplifier (EDFA) EDFA for the first time, pass through filter filtering afterwards.The polarizer is used to adjust the auroral poles property from wave filter output.Electrooptic modulator gets access to the control input from pulse producer, produces optical pulse.The light pulse of output is sent to measuring fiber through circulator then through scrambler.
Brillouin's signal is converted to electric signal through circulator by photodetector.Electrical signal converted is collected through data collecting card, is input to system's control computer through Ethernet interface.
Distribution type fiber-optic Brillouin strain and temperature sensor use the PID controller, come locking frequency difference and biasing through the minimum leakage level that amplifies pulse signal.The PID controller guarantees that the beat frequency of two distributed feed-back formula laser instruments is locked in Brillouin's frequency.The PID controller uses two the independently electric current and the temperature of two distributed feed-back formula laser instruments of current controller control respectively.
Distribution type fiber-optic Brillouin strain and temperature sensor use the polarizer and scrambler, reduce the power swing that change in polarity causes.
This distributed sensor based on distributed feed-back formula laser instrument has solved the deficiency of system before, can produce to be superior to 1 meter spatial resolution.The utility model has the following advantages than system before: use distributed feed-back formula laser instrument to replace frequency stabilization and tunable laser system, thereby significantly reduce the cost of sensing system.
Description of drawings
Fig. 1 is the connection synoptic diagram of the utility model.
Embodiment
Below in conjunction with accompanying drawing the utility model is carried out detailed explanation:
As shown in Figure 1; The utility model comprises detecting laser 1, pump laser 2, detection optical fiber 12, two 95: 5 fiber couplers (41; 42), 50: 50 fiber couplers 17, two photodetectors (13,16), Erbium-Doped Fiber Amplifier (EDFA) 5, wave filter 6, data collecting card 14, PID controller 19, two current controllers (31,32), the polarizer 7, scrambler 10, pulse producer 9, electrooptic modulator 8, circulator 11, isolator 15 and computing machines 18; The input end of P ID controller 19 links to each other with computing machine 18; The output terminal of PID controller 19 is continuous with the input end of two current controllers (31,32) respectively, two current controllers (31; 32) output terminal links to each other with the input end of detecting laser 1, pump laser 2 respectively; The output terminal of detecting laser 1 links to each other with the input end of 95: 5 fiber coupler 41, and an output terminal of this 95: 5 fiber couplers 41 links to each other with the input end of Erbium-Doped Fiber Amplifier (EDFA) 5, and another output terminal of this 95: 5 fiber couplers 41 links to each other with an input end of 50: 50 fiber couplers 17; The output terminal of Erbium-Doped Fiber Amplifier (EDFA) 5 links to each other with the input end of wave filter 6; The output terminal of wave filter 6 links to each other with the input end of the polarizer 7, and the input end of pulse producer 9 links to each other with computing machine 18, and the output terminal of pulse producer 9 links to each other with an input end of electrooptic modulator 8; The output terminal 7 of the polarizer links to each other with another input end of electrooptic modulator 8; The output terminal of electrooptic modulator 8 links to each other with the input end of scrambler 10, and the output terminal of scrambler 10 links to each other with the input end of circulator 11, and the common port of circulator 11 links to each other with detection optical fiber 12; The output terminal of circulator 11 links to each other with the input end of a photodetector 13, and the output terminal of this photodetector 13 links to each other with computing machine 18 with data collecting card 14 successively; The output terminal of pump laser 2 links to each other with the input end of another 95: 5 coupling mechanisms 42; An output terminal of another 95: 5 fiber couplers 42 links to each other with the input end of isolator 15; The output terminal of isolator 15 links to each other with detection optical fiber 12; Another output terminal of another 95: 5 fiber couplers 42 links to each other with another input end of 50: 50 fiber couplers 17; The output terminal of 50: 50 fiber couplers 17 links to each other with the input end of another photodetector 16, and the output terminal of another photodetector 16 links to each other with computing machine 18 with data collecting card 14 successively.Described detecting laser, pump laser are respectively distributed feed-back formula laser instrument.
Distribution type fiber-optic Brillouin strain and temperature sensor use two distributed feed-back formula laser instruments.Distributed feed-back formula laser instrument 2 is as pump laser, and current controller 32 Control current source and temperature are used for stablizing the temperature of distributed feed-back formula laser instrument 2.Separated by 95: 5 fiber couplers from the light beam of distributed feed-back formula laser instrument 2 outputs.Percent Five Classics 50: 50 fiber couplers, photodetectors 17 of sending light beam are sent to data collecting card.95% light is transferred to measuring fiber then through an isolator output.
Distributed feed-back formula laser instrument 1 is as detecting laser, and wavelength is 1550nm.Current controller 31 Control current source and temperature are used for stablizing the temperature of distributed feed-back formula laser instrument 1.Separated by 95: 5 fiber couplers from the light beam of distributed feed-back formula laser instrument 1 output, percent Five Classics 50: 50 fiber couplers, photodetectors 17 of sending light beam are sent to data collecting card.All the other output light of 95% are amplified by Erbium-Doped Fiber Amplifier (EDFA) EDFA for the first time, pass through filter filtering afterwards.The polarizer is used to adjust the auroral poles property from wave filter output.Electrooptic modulator gets access to the control input from pulse producer, produces optical pulse.The light pulse of output is sent to measuring fiber through circulator then through scrambler.
Brillouin's signal is converted to electric signal through circulator by photodetector.Electrical signal converted is collected through data collecting card, is input to system's control computer through Ethernet interface.
Distribution type fiber-optic Brillouin strain and temperature sensor use the PID controller, come locking frequency difference and biasing through the minimum leakage level that amplifies pulse signal.The PID controller guarantees that the beat frequency of two distributed feed-back formula laser instruments is locked in Brillouin's frequency.The PID controller uses two the independently electric current and the temperature of two distributed feed-back formula laser instruments of current controller control respectively.

Claims (2)

1. distribution type fiber-optic Brillouin strain and temperature sensor; Comprise detecting laser, pump laser, detection optical fiber, two 95: 5 fiber couplers, 50: 50 fiber couplers, two photodetectors, Erbium-Doped Fiber Amplifier (EDFA), wave filter, data collecting card, PID controller, two current controllers, the polarizer, scrambler, pulse producer, electrooptic modulator, circulator, isolator and computing machines; It is characterized in that: the input end of PID controller links to each other with computing machine; The output terminal of PID controller links to each other with the input end of two current controllers respectively; The output terminal of two current controllers links to each other with the input end of detecting laser, pump laser respectively; The output terminal of detecting laser links to each other with the input end of 95: 5 fiber coupler, and an output terminal of this 95: 5 fiber couplers links to each other with the input end of Erbium-Doped Fiber Amplifier (EDFA), and another output terminal of this 95: 5 fiber couplers links to each other with an input end of 50: 50 fiber couplers; The output terminal of Erbium-Doped Fiber Amplifier (EDFA) links to each other with the input end of wave filter; The output terminal of wave filter links to each other with the input end of the polarizer, and the input end of pulse producer links to each other with computing machine, and the output terminal of pulse producer links to each other with an input end of electrooptic modulator; The output terminal of the polarizer links to each other with another input end of electrooptic modulator; The output terminal of electrooptic modulator links to each other with the input end of scrambler, and the output terminal of scrambler links to each other with the input end of circulator, and the common port of circulator links to each other with detection optical fiber; The output terminal of circulator links to each other with the input end of a photodetector, and the output terminal of this photodetector links to each other with computing machine with data collecting card successively; The output terminal of pump laser links to each other with the input end of another 95: 5 coupling mechanisms; An output terminal of another 95: 5 fiber couplers links to each other with the input end of isolator; The output terminal of isolator links to each other with detection optical fiber; Another output terminal of another 95: 5 fiber couplers links to each other with another input end of 50: 50 fiber couplers; The output terminal of 50: 50 fiber couplers links to each other with the input end of another photodetector, and the output terminal of another photodetector links to each other with computing machine with data collecting card successively.
2. distribution type fiber-optic Brillouin according to claim 1 strain and temperature sensor is characterized in that: described detecting laser, pump laser are distributed feed-back formula laser instrument.
CN2012201153284U 2012-03-26 2012-03-26 Distributed fiber Brillouinstrain strain and temperature sensor Withdrawn - After Issue CN202533198U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102620856A (en) * 2012-03-26 2012-08-01 湖北擎宇科技有限公司 Distributed optical fiber Brillouin strain and temperature sensor
CN104198084A (en) * 2014-08-26 2014-12-10 河海大学 Closed-loop feedback type passive waveguide micro temperature sensor
CN106932083A (en) * 2017-03-19 2017-07-07 国网福建省电力有限公司 A kind of optical-fiber wireless vibrating sensor device based on high-intensity magnetic field background

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102620856A (en) * 2012-03-26 2012-08-01 湖北擎宇科技有限公司 Distributed optical fiber Brillouin strain and temperature sensor
CN102620856B (en) * 2012-03-26 2013-05-08 湖北擎宇科技有限公司 Distributed optical fiber Brillouin strain and temperature sensor
CN104198084A (en) * 2014-08-26 2014-12-10 河海大学 Closed-loop feedback type passive waveguide micro temperature sensor
CN104198084B (en) * 2014-08-26 2015-08-26 河海大学 Closed-loop feed-back type passive wave guide micro temperature sensor
CN106932083A (en) * 2017-03-19 2017-07-07 国网福建省电力有限公司 A kind of optical-fiber wireless vibrating sensor device based on high-intensity magnetic field background
CN106932083B (en) * 2017-03-19 2020-09-04 国网福建省电力有限公司 Optical fiber wireless vibration sensor device based on high-intensity magnetic field background

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