CN107436201A - Distributed fiber optic temperature strain sensing system and method based on Brillouin scattering - Google Patents
Distributed fiber optic temperature strain sensing system and method based on Brillouin scattering Download PDFInfo
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- 239000000835 fiber Substances 0.000 title claims abstract description 58
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- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims description 3
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- 239000013307 optical fiber Substances 0.000 abstract description 14
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
- G01K11/322—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres using Brillouin scattering
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
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Abstract
The invention discloses a kind of distributed fiber optic temperature strain sensing system and method based on Brillouin scattering, send to transfer to other localities through electrooptic modulator after the continuous light of narrow linewidth using distributed feedback laser and pulsed light is made, it is amplified afterwards using erbium-doped fiber amplifier, exaggerated pulsed light enters sensor fibre to obtain Brillouin's backscatter signal in the optical fiber as incident light.The present invention obtains brillouin scattering signal by the way of single ended input, is easy to installing and using for system；Propose using homologous heterodyne interferometry come demodulated signal, avoid requirement of the general interferometric method to two-beam similar intensity, simplify test system；Certain measure is taken to strengthen signal, in order to subsequent treatment；The change of Brillouin shift and intensity is obtained simultaneously using method for electrically simultaneously, temperature and strain are demodulated, realized to being measured while the two.
Description
Technical field
The present invention relates to distributing optical fiber sensing field, specifically a kind of distributed fiber optic temperature based on Brillouin scattering
Strain sensing system and method.
Background technology
Distributed optical fiber sensing system can be defined as：Can be on continuous fiber lengths, with the continuous function of distance
Form senses out instrument or the system that measured parameter changes with fiber length.Distributed temperature, stress sensing system are led to
Be often by optical fiber along temperature field, stress field arrange, measurement light transmit in a fiber caused by carry temperature, stress information dissipate
Light is penetrated, while uses optical time domain reflectometer OTDR (Optical Time Domain Reflectometer) technology, it is possible to be right
The information for being distributed and changing over time along the temperature on optical fiber transmission path, stress-space is measured and monitored.
Distributed sensing technical research based on Brillouin scattering is started late, but because it is in temperature, strain measurement
Measurement accuracy, measurement range and the spatial resolution reached is above other Distributed Optical Fiber Sensing Techniques, therefore this
Technology at present obtaining extensive concern with research, be also advantageously applied to tunnel deformation monitoring, dam structure health monitoring and
Large-scale civil engineering monitoring structural health conditions etc..Not yet effectively solve the problems, such as mainly have at present：First, the single-ended measurement system of optical fiber
Unite the weak detection difficult of easy for installation but signal, and the installation inconvenience of double-end measurement system；Two be due to optical branch phonon in optical fiber
Short life, cause to accurately measure the life-span that the pulsewidth of Brillouin scattering optical frequency shift then incident light is significantly larger than phonon, this is just
Cause low spatial resolution；Third, no cost-effective method come solve temperature regulating and strain two big parameters.This to be based on
The performance of distributed sensing system index of Brillouin scattering can not further be substantially improved, and also make it that the technology can not extensive business
With change.
The content of the invention
For the deficiencies in the prior art, invention provides a kind of distributed fiber optic temperature based on Brillouin scattering
Strain sensing system, it is intended to solve the problems, such as Brillouin scattering optical signal detecting difficulty in the prior art, detection signal is weak or pacifies
The problem of dress is complicated, manufacturing cost is high, and temperature and strain be demodulated to Ben Gao and it is inapplicable the problem of.
The technical scheme is that：
A kind of distributed fiber optic temperature strain sensing system based on Brillouin scattering, including：
Laser, the first coupler, electrooptic modulator, erbium-doped fiber amplifier, circulator, sensor fibre, Raman filtering
Device, the second coupler, the first photodetector, low pass filter, amplifier, the 3rd coupler, the second photodetector, radio frequency
Amplifier, high-pass filter, power splitter, the first microwave detector, the first low-frequency amplifier, frequency-strength converter,
Two microwave detectors, the second low-frequency amplifier and data processing module；
Incident light caused by laser is divided into tie point and the second branch road, the outgoing of tie point after the first coupler
Light produces rear orientation light, back scattering after passing sequentially through electrooptic modulator, erbium-doped fiber amplifier, circulator, sensor fibre
Light is divided into the 3rd branch road and the 4th branch road after Raman wave filter by the second coupler；The emergent light of 3rd branch road passes through successively
Gathered and handled by data processing module after first photodetector, low pass filter, amplifier, obtain first passage data；
The emergent light of 4th branch road is coupled with the emergent light of the second branch road in the 3rd coupler, and coupling emergent light enters the second light
Homologous difference interference is carried out in electric explorer, is then entered again after radio frequency amplifier, high-pass filter in power splitter
Row power distribution, the emergent light after power distribution are divided into two-way output, and the emergent light of the first output enters the first microwave sounding
Device, then gathered and handled by data processing module after the first low-frequency amplifier, obtain second channel data；Second output
Emergent light first passes through frequency-strength converter, then by data processing after the second microwave detector and the second low-frequency amplifier
Module gathers and processing, obtains third channel data.
Wherein, the emergent light of tie point is connected by electrooptic modulator with erbium-doped fiber amplifier；Erbium-doped fiber amplifier
Device is connected with the first port of circulator；Circulator second port one end access sensor fibre, the 3rd port of circulator with
Raman wave filter is connected；The output end of Raman wave filter is connected with the input of the second coupler；The first of second coupler is defeated
Go out end successively with the first photodetector, low pass filter, amplifier and data processing module；
The emergent light of the second output end emergent light and the second branch road of 3rd coupler while the second coupler of reception, the 3rd
The output end of coupler is connected with the second photodetector, radio frequency amplifier, high-pass filter and power splitter successively, through work(
Emergent light after rate distribution is divided into two-way output, and the emergent light of the first output enters the first microwave detector, then passes through first
Low-frequency amplifier is connected with data processing module；The emergent light of second output enters frequency-strength converter, then passes sequentially through
It is connected after second microwave detector, the second low-frequency amplifier with data processing module.
Further, the laser is distributed feedback laser.
Further, the splitting ratio of first coupler is 98:2；Point of second coupler and the 3rd coupler
Light ratio is 75:25.
Further, the electrooptic modulator uses lithium niobate intensity modulator, for laser output continuous light with
Just suitable pulsed light is obtained.
Further, the work pump light source of erbium-doped fiber amplifier is the two directional pump light source of 980nm wavelength.
Further, the frequency response of the first photodetector is more than 125MHz, and the second photodetector is 3kHz-
12GHz。
The invention also provides a kind of distributed fiber optic temperature strain sensing measuring method using said system, including：
Brillouin scattering luminous intensity is obtained according to first passage data and second channel data；According to second channel data and
Third channel data obtain Brillouin shift, that is, obtain in cloth caused by the temperature change experienced as sensor fibre or strain
The Strength Changes of deep rear orientation light and frequency displacement change, the changing value of temperature is obtained by Brillouin scattering luminous intensity, further according to
The frequency displacement change and the change of temperature are worth to the strain that sensor fibre is experienced, and realize to being surveyed while temperature and strain
Amount.
Further, it is described to obtain Brillouin scattering luminous intensity according to first passage data and second channel data and include：
Obtained first including Rayleigh scattering luminous intensity and Brillouin scattering according to first passage data and second channel data
Photoelectric current including luminous intensity, the electromagnetic field expressions based on Rayleigh scattering light, Brillouin scattering, separation show that Brillouin dissipates
Penetrate luminous intensity.
Further, the first passage data are direct current signal, and second channel data and third channel data are to exchange
Signal.
Beneficial effects of the present invention：
Compared with prior art, the present invention is using homologous difference interference method come demodulated signal, and this kind of method is same
Source difference interference, the requirement typically interfered to two-beam similar intensity is avoided using homologous difference interference, simplify test system
System；Solves input light arteries and veins using the light that a tuftlet and Rayleigh scattering light same frequency are isolated from light source to strengthen rear orientation light
The contradiction of width and spatial resolution is rushed, avoids using high-precision filter；Brillouin scattering letter is differentiated using method for electrically
Number frequency displacement and Strength Changes, and then demodulate temperature and strain, compared to conventional method, flashing or light path can eliminated
The extraneous factors such as disturbance reduce cost on the premise of influenceing.
Brief description of the drawings
Fig. 1 is the knot of the distributed fiber optic temperature strain sensing system provided in an embodiment of the present invention based on Brillouin scattering
Composition.
Fig. 2 is the circuit part structure chart of the method for electrically of demodulation temperature strain provided in an embodiment of the present invention.
Fig. 3 is system test result figure provided in an embodiment of the present invention.
Wherein, distributed feedback laser 1, the first coupler 2, electrooptic modulator 3, erbium-doped fiber amplifier 4, circulator
5th, sensor fibre 6, Raman wave filter 7, the second coupler 8, the first photodetector 9, low pass filter 10, amplifier 11,
Three couplers 12, the second photodetector 13, radio frequency amplifier 14, high-pass filter 15, power splitter 16, the first microwave are visited
Survey device 17, the first low-frequency amplifier 18, frequency-strength converter 19, the second microwave detector 20, the and of the second low-frequency amplifier 21
Data processing module 22.
Embodiment：
The invention will be further described with embodiment below in conjunction with the accompanying drawings：
It is noted that described further below is all exemplary, it is intended to provides further instruction to the application.It is unless another
Indicate, all technologies used herein and scientific terminology are with usual with the application person of an ordinary skill in the technical field
The identical meanings of understanding.
It should be noted that term used herein above is merely to describe embodiment, and be not intended to restricted root
According to the illustrative embodiments of the application.As used herein, unless the context clearly indicates otherwise, otherwise singulative
It is also intended to include plural form, additionally, it should be understood that, when in this manual using term "comprising" and/or " bag
Include " when, it indicates existing characteristics, step, operation, device, component and/or combinations thereof.
Homologous difference interference refers to：Using the tuftlet light isolated from light source homologous phase is used as with Rayleigh scattering light
Dry light, is interfered, and strengthens rear orientation light, solves the contradiction of input optical pulse width and spatial resolution, can avoid
Use high-precision filter.
As previously described, the distributed optical fiber sensing system based on Brillouin scattering also exists not yet effectively solve at present
Certainly the problem of, mainly has：First, the single-ended measuring system of optical fiber is easy for installation but the weak detection difficult of signal, and double-end measurement system is pacified
Dress inconvenience；Two be due to the short life of optical branch phonon in optical fiber, causes then to enter to accurately measure Brillouin scattering optical frequency shift
The pulsewidth for penetrating light is significantly larger than the life-span of phonon, and this results in low spatial resolution；Third, no cost-effective method is come
Solve two big parameters of temperature regulating and strain.
In order to solve the above problems, a kind of exemplary embodiments of the invention are：
Sensor-based system includes：Distributed feedback laser 1, the first coupler 2, electrooptic modulator 3, erbium-doped fiber amplifier
4th, circulator 5, sensor fibre 6, Raman wave filter 7, the second coupler 8, the first photodetector 9, low pass filter 10, amplification
Device 11, the 3rd coupler 12, the second photodetector 13, radio frequency amplifier 14, high-pass filter 15, power splitter 16,
One microwave detector 17, the first low-frequency amplifier 18, frequency-strength converter 19, the second microwave detector 20, the second low frequency are put
Big device 21 and data processing module 22；The input connecting laser 1 of first coupler 2, the input connection of electrooptic modulator 3
To the first output end of the first coupler 2, the input of erbium-doped fiber amplifier 4 is connected to the output end of electrooptic modulator 3, ring
The first port of shape device 5 is connected to the output end of erbium-doped fiber amplifier 4, and sensor fibre 6 is connected to the second end of circulator 5
Mouthful, the input of Raman wave filter 7 is connected to the 3rd port of circulator 5, and the input of the second coupler 8 is connected to Raman filter
The output end of ripple device 7, the input of the first photodetector 9 are connected to the first output end of the second coupler 8, low pass filter
10 input is connected to the output end of the first photodetector 9, and the input of amplifier 11 is connected to low pass filter 10
Output end, the output end connection data processing module 22 of amplifier 11；
The first input end of 3rd coupler 12 is connected to the second output end of the second coupler 8, the 3rd coupler 12
Second input is connected to the second output end of the first coupler 2, and the input of the second photodetector 13 is connected to the 3rd coupling
The output end of clutch 12, the input of radio frequency amplifier 14 are connected to the output end of the second photodetector 13, high-pass filter
15 input is connected to the output end of radio frequency amplifier 14, and the input of power splitter 16 is connected to high-pass filter 15
Output end, the input of the first microwave detector 17 are connected to the first output end of power splitter 16, the first low-frequency amplifier
18 input is connected to the output end of the first microwave detector 17, the output end connection data processing of the first low-frequency amplifier 18
Module 22；
The input of frequency-strength converter 19 is connected to the second output end of power splitter 16, the second microwave sounding
The input of device 20 is connected to the output end of frequency-strength converter 19, and the input of the second low-frequency amplifier 21 is connected to
The output end of two microwave detectors 20, the output end connection data processing module 22 of the second low-frequency amplifier 21.
Laser is distributed feedback laser；The splitting ratio of first coupler is 98:2；Second coupler and
The splitting ratio of three couplers is 75:25；Electrooptic modulator modulates the continuous of laser output from lithium niobate intensity modulator
Light is to obtain suitable pulsed light；The two directional pump of 980nm wavelength should be selected in erbium-doped fiber amplifier structure；First photoelectricity
Detector is 125MHz, and the second photodetector is 3kHz-12GHz.
The light that laser 1 exports is divided into first via light and the second road light through the first coupler 2；First via light passes sequentially through light
Rear orientation light is produced after electric modulator 3, erbium-doped fiber amplifier 4, circulator 5, sensor fibre 6, scattering light is filtered by Raman
The 3rd road light and the 4th road light are divided into by the second coupler 8 after ripple device 7；3rd road light is successively by the first photodetector 9, low
Data acquisition and procession is carried out by data processing module 22 after bandpass filter 10, amplifier 11, is passage 1. data；4th road light
Mixed with the second road light in the 3rd coupler 12, mixed light, which enters in the second photodetector 13, to carry out homologous heterodyne and do
Relate to, then power distribution is carried out in rate beam splitter 16 after radio frequency amplifier 14, high-pass filter 15, be directly entered all the way
One microwave detector 17, data acquisition and procession is then carried out by data processing module 22 after the first low-frequency amplifier 18, is
Passage 2. data；Another way first passes through frequency-strength converter 19, and then is put by the second microwave detector 20 and the second low frequency
Data acquisition and procession is carried out by data processing module 22 after big device 21, is passage 3. data.
Scattering light in a fiber mainly includes Rayleigh scattering light, Brillouin scattering and Raman diffused light.Due to Raman
Very big, the about 100nm with the centre wavelength difference of Rayleigh scattering light, therefore in general optical filter can be used to filtering out Raman and dissipate
Light is penetrated, there was only Rayleigh and Brillouin scattering in such rear orientation light.Brillouin scattering is including Stokes composition and instead
Stokes composition, if however, spontaneous brillouin scattering light, when only detecting Brillouin shift, utilizes the inspection in the present invention
Survey method, without considering anti Stokes components, because in Brillouin scattering, stoke caused by temperature and strain variation
This composition is consistent with the moving direction of anti Stokes components；If stimulated Brillouin scattering, in Brillouin scattering,
For Stokes composition, anti Stokes components are quite faint, so anti Stokes components can be ignored.Always
It, the ac output end mouth of 12GHz high-frequency detector only exports Brillouin's Stokes and the interference of Rayleigh scattering light is handed over
Flow signal.
Assuming that the electromagnetic field of the electromagnetic field of Rayleigh scattering light and Brillouin scattering (Stokes composition) light is as follows：ER(t)
=ER cos(ωRt+φR), EB(t)=EB cos(ωRt+φB) ... (1) wherein R represents Rayleigh scattering light, and B is represented in cloth
Deep pool scattering light.In view of frequency band is the spectrum individual features and frequency response characteristic of 10KHz-12GHz high frequency photo-detector, can be with
Obtaining output light electric current is：
The AC signal relevant with Brillouin shift thus can be obtained from the ac output end mouth of high frequency detector.
In the method for homologous difference interference of the present invention, no matter Rayleigh scattering light or Brillouin scattering obtain
Heterodyne interference signal can be strengthened to reinforcement, in view of the rear orientation light in sensor fibre is very weak, divide using from light source
Strengthen flashlight from sub-fraction light, i.e., 2% light and sensing are isolated from laser with 98/2 the first photo-coupler 1
The rear orientation light of optical fiber enters in high frequency light electric explorer after merging, so as to reach the purpose for strengthening interference signal.This method
Foundation be that backward Rayleigh scattering is elastic scattering, and frequency is constant, it is consistent with the frequency of primary source.
Fig. 2 is the circuit part structure chart of the method for electrically of demodulation temperature strain provided in an embodiment of the present invention.Lead in fig. 2
1. data are direct current component (α are conversion coefficients) in road, and 2. and 3. data are AC portions to passage.Passage 2. data signal with
The change of back scattering luminous intensity and change, it is unrelated with the change of Brillouin shift.Passage 3. data signal not only with backward
The change of scattered light intensity about and with Brillouin shift it is relevant.It is it is possible to 1. and logical according to passage in a computer
The data of road 2. are by being calculated Rayleigh scattering luminous intensity ERWith Brillouin scattering luminous intensity EB；On the other hand, can be according to logical
Data of the road 2. with passage 3. are obtained not by the Brillouin shift of Strength Changes.Therefore, can obtain being experienced by sensor fibre
Temperature change or strain caused by Brillouin's rear orientation light Strength Changes and frequency displacement change, and not by flashing and
The influence of the factors such as light path bending.And the change for straining caused Brillouin scattering luminous intensity is very faint, cause than temperature
Brillouin scattering luminous intensity small 3 orders of magnitude of change, so the change of Brillouin scattering luminous intensity caused by negligible strain
Change.Therefore the changing value of temperature can be obtained by the change of Brillouin scattering luminous intensity, then further according to Brillouin shift
Change and the change of temperature obtain the size for the strain that sensor fibre is experienced.
Fig. 3 is to be based on above step, the temperature and strain with Brillouin that the system progress experimental verification to the present invention obtains
The relation that frequency displacement changes and changed, demonstrates the feasibility of the system method therefor, also absolutely proves that the system can realize temperature
Degree and the detection of strain, and the coefficient uniformity of gained coefficient and predecessor's report is fine.
The size that the present invention considers Brillouin scattering optical frequency shift is decided by SVEL, therefore the temperature of sensor fibre impression
Degree and strain can influence the SVEL of inside of optical fibre, and we can obtain sensor fibre by measuring brillouin frequency in-migration whereby
The temperature of impression or strain.On the other hand, the intensity of Brillouin scattering is also influenceed by temperature and strain, so passing through measurement
The frequency displacement of Brillouin scattering and Strength Changes, and demodulate can while measure temperature and the strain of sensor fibre impression.
The present invention is proposed using homologous difference interference method come demodulated signal, is avoided and is typically interfered to two-beam intensity
Similar requirement, simplifies test system；Added using the light that a tuftlet and Rayleigh scattering light same frequency are isolated from light source
Strong rear orientation light solves the contradiction of input optical pulse width and spatial resolution, avoids using high-precision filter；Using
Method for electrically differentiates the frequency displacement of brillouin scattering signal and Strength Changes, and then demodulates temperature and strain, compared to tradition side
Method, cost can be reduced on the premise of eliminating the extraneous factor such as flashing or optical path disturbance and influenceing.
The present invention includes but not only limited using the distributed optical fiber sensing system based on Brillouin scattering, technology used
(BOTDA) method and optical time domain Brillouin reflectometer (BOTDR) method etc. are analyzed in optical time domain Brillouin.
The preferred embodiment of the application is the foregoing is only, is not limited to the application, for the skill of this area
For art personnel, the application can have various modifications and variations.It is all within spirit herein and principle, made any repair
Change, equivalent substitution, improvement etc., should be included within the protection domain of the application.
Claims (10)
- A kind of 1. distributed fiber optic temperature strain sensing system based on Brillouin scattering, it is characterised in that including：Laser, the first coupler, electrooptic modulator, erbium-doped fiber amplifier, circulator, sensor fibre, Raman wave filter, Two couplers, the first photodetector, low pass filter, amplifier, the 3rd coupler, the second photodetector, radio frequency amplification It is device, high-pass filter, power splitter, the first microwave detector, the first low-frequency amplifier, frequency-strength converter, second micro- Wave detector, the second low-frequency amplifier and data processing module；Incident light caused by laser is divided into tie point and the second branch road after the first coupler, the emergent light of tie point according to It is secondary by producing rear orientation light after electrooptic modulator, erbium-doped fiber amplifier, circulator, sensor fibre, rear orientation light warp Cross after Raman wave filter and the 3rd branch road and the 4th branch road are divided into by the second coupler；The emergent light of 3rd branch road passes through first successively Gathered and handled by data processing module after photodetector, low pass filter, amplifier, obtain first passage data；4th The emergent light of branch road is coupled with the emergent light of the second branch road in the 3rd coupler, and coupling emergent light is visited into the second photoelectricity Survey in device and carry out homologous difference interference, then carry out work(in power splitter after radio frequency amplifier, high-pass filter again Rate is distributed, and the emergent light after power distribution is divided into two-way output, and the emergent light of the first output enters the first microwave detector, so Gathered by data processing module and handled by after the first low-frequency amplifier, obtain second channel data；The outgoing of second output Light first passes through frequency-strength converter, then by data processing module after the second microwave detector and the second low-frequency amplifier Collection and processing, obtain third channel data.
- 2. the distributed fiber optic temperature strain sensing system according to claim 1 based on Brillouin scattering, its feature exist In,The emergent light of tie point is connected by electrooptic modulator with erbium-doped fiber amplifier；Erbium-doped fiber amplifier and circulator First port be connected；Second port one end access sensor fibre of circulator, the 3rd port and the Raman wave filter of circulator It is connected；The output end of Raman wave filter is connected with the input of the second coupler；First output end of the second coupler successively with First photodetector, low pass filter, amplifier and data processing module；3rd coupler receives the second output end emergent light of the second coupler and the emergent light of the second branch road, the 3rd coupling simultaneously The output end of device is connected with the second photodetector, radio frequency amplifier, high-pass filter and power splitter successively, through power point Emergent light after matching somebody with somebody is divided into two-way output, and the emergent light of the first output enters the first microwave detector, then passes through the first low frequency Amplifier is connected with data processing module；The emergent light of second output enters frequency-strength converter, then passes sequentially through second It is connected after microwave detector, the second low-frequency amplifier with data processing module.
- 3. the distributed fiber optic temperature strain sensing system according to claim 1 based on Brillouin scattering, its feature exist In the laser is distributed feedback laser.
- 4. the distributed fiber optic temperature strain sensing system according to claim 1 based on Brillouin scattering, its feature exist In the splitting ratio of first coupler is 98:2；The splitting ratio of second coupler and the 3rd coupler is 75:25.
- 5. the distributed fiber optic temperature strain sensing system according to claim 1 based on Brillouin scattering, its feature exist In the electrooptic modulator uses lithium niobate intensity modulator, and the continuous light for laser output is to obtain suitable arteries and veins Wash off.
- 6. the distributed fiber optic temperature strain sensing system according to claim 1 based on Brillouin scattering, its feature exist In the work pump light source of erbium-doped fiber amplifier is the two directional pump light source of 980nm wavelength.
- 7. the distributed fiber optic temperature strain sensing system according to claim 1 based on Brillouin scattering, its feature exist In the frequency response of the first photodetector is more than 125MHz, and the second photodetector is 3kHz-12GHz.
- A kind of 8. distributed fiber optic temperature strain sensing measuring method based on claim 1, it is characterised in that：Brillouin scattering luminous intensity is obtained according to first passage data and second channel data；According to second channel data and the 3rd Channel data obtains Brillouin shift, that is, after obtaining Brillouin caused by the temperature change experienced as sensor fibre or strain Strength Changes and frequency displacement change to scattering light, obtain the changing value of temperature, further according to described by Brillouin scattering luminous intensity Frequency displacement change and the change of temperature are worth to the strain that sensor fibre is experienced, and realize to being measured while temperature and strain.
- 9. according to the method for claim 8, it is characterised in that described to be obtained according to first passage data and second channel data Include to Brillouin scattering luminous intensity：Obtained first including Rayleigh scattering luminous intensity and Brillouin scattering light intensity according to first passage data and second channel data Photoelectric current including degree, the electromagnetic field expressions based on Rayleigh scattering light, Brillouin scattering, separation draw Brillouin scattering Intensity.
- 10. according to the method for claim 8, it is characterised in that the first passage data are direct current signal, second channel Data and third channel data are AC signal.
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