CN206974448U - The joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering - Google Patents
The joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering Download PDFInfo
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- CN206974448U CN206974448U CN201721011488.3U CN201721011488U CN206974448U CN 206974448 U CN206974448 U CN 206974448U CN 201721011488 U CN201721011488 U CN 201721011488U CN 206974448 U CN206974448 U CN 206974448U
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Abstract
The utility model discloses a kind of joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering, including microwave signal source, Distributed Feedback Laser, first fiber coupler, second fiber coupler, first electrooptic modulator, second electrooptic modulator, grating filter, first EDFA Erbium-Doped Fiber Amplifier, second EDFA Erbium-Doped Fiber Amplifier, 3rd EDFA Erbium-Doped Fiber Amplifier, first light opens the light, second photoswitch, 3rd photoswitch, scrambler, impulse generator, wavelength division multiplexer, sensor fibre, first photodetector, second photodetector, optical fiber circulator, data acquisition unit and intelligent apparatus；The sensing device can measurement temperature and strain simultaneously, can reduce the measurement that environmental change brings influences, and improves the measuring precision, system reliability and response speed.
Description
Technical field
It the utility model is related to a kind of joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering.
Background technology
Distributed Raman fiber sensor has long-distance distributed measurement, electromagnetism interference, small and light etc. many excellent
Point, real time temperature is needed city gas pipeline, transmission of electricity/communication cable, reservoir dam, bridge, tunnel, highway etc. are many
There is extensive use in the field of monitoring.
Main formula Raman fiber temperature sensor and the distributed Brillouin fiber optic temperature/should of being distributed being widely used at present
Become sensor.Wherein Raman fiber sensor only carries out temperature survey, and Brillouin light fiber sensor can be used for temperature and strain
Two parameter measurement, but because Brillouin scattering can not be measured temperature and the cross-sensitivity of strain, the two parameters simultaneously, limit
Its application is made.
Raman fiber sensor-based system is only temperature sensitive.Distributed Raman fiber sensor carries out temperature demodulation typically to draw
Graceful scattering anti-Stokes light is flashlight, and stokes light is reference light, using the ratio solution temperature regulating of the two.This demodulation
Method can eliminate the error that static fibre loss is brought, but can not eliminate error caused by Wavelength Dependent Loss.
Brillouin spectrum frequency displacement is all sensitive to temperature and strain.Distributing optical fiber sensing system based on Brillouin scattering
System, solving the cross-sensitivity of Brillouin frequency shifts turns into the key technical problem for realizing double parameters while measurement.It is main at present
There are following three kinds of solution methods：
1st, demodulated while trip temperature and strain are entered in joint Brillouin scattering luminous power and Brillouin spectrum frequency displacement.The party
For method because luminous power is very low for the sensitivity coefficient of strain, the luminous power error of detection limits temperature strain while the essence of demodulation
Degree.
2nd, while trip temperature and strain are entered in joint Brillouin spectrum frequency displacement and Brillouin's dynamic raster reflectance spectrum frequency displacement
Demodulation, the program can obtain good measurement accuracy, but must use polarization maintaining optical fibre, and sensor fibre distance is generally less than
1km, limit its application in terms of length is away from detection.
3rd, combine Brillouin spectrum frequency displacement and Raman scattering luminous power demodulated while temperature and strain.Utilize drawing
Graceful scattering optical power detecting sensing temperature, then strain is gone out by Brillouin spectrum shifting demodulation, while realizing temperature strain
Measurement.
At present, the sensing device based on the third above-mentioned scheme is typically all by the way of single-ended detection, with reference to distribution
Raman fiber sensor and Brillouin light fiber sensor demodulate while realizing temperature strain.The A " one of patent CN 102313568
The distribution type optical fiber sensing equipment that kind Brillouin and Raman detect simultaneously " is exactly a Typical Representative of the program.
Utility model content
The utility model provides a kind of joint Raman of both-end detection and the distributing optical fiber sensing dress of Brillouin scattering
Put, which overcome the deficiencies in the prior art described in background technology.
Technical scheme is used by the utility model solves its technical problem：
Both-end detection joint Raman and Brillouin scattering distribution type optical fiber sensing equipment, it include microwave signal source,
Distributed Feedback Laser, the first fiber coupler, the second fiber coupler, the first electrooptic modulator, the second electrooptic modulator, grating filter
Ripple device, the first EDFA Erbium-Doped Fiber Amplifier, the second EDFA Erbium-Doped Fiber Amplifier, the 3rd EDFA Erbium-Doped Fiber Amplifier, the first light open the light, second
Photoswitch, the 3rd photoswitch, scrambler, impulse generator, wavelength division multiplexer, sensor fibre, the first photodetector, the second light
Electric explorer, optical fiber circulator, data acquisition unit and intelligent apparatus；
The output end of Distributed Feedback Laser is connected with the input of the first fiber coupler, an output of the first fiber coupler
End is connected with a light input end of the first electrooptic modulator, another output end and a light input end phase of the second electrooptic modulator
Even；
The output end of microwave signal source is connected with the rf inputs of the first electrooptic modulator, the first electrooptic modulator it is defeated
Go out end with the input of grating filter to be connected, the output end of grating filter and the input phase of the first EDFA Erbium-Doped Fiber Amplifier
Even, the output end of the first EDFA Erbium-Doped Fiber Amplifier is connected with the input of scrambler, the output end of scrambler and the first photoswitch
Its Two-port netwerk be connected, the one port of the first photoswitch is connected with the one port of sensor fibre；
The output end of second electrooptic modulator is connected with the input of the second EDFA Erbium-Doped Fiber Amplifier, and the second erbium-doped fiber is put
The output end of big device is connected with the input of the second fiber coupler, and an output end and the 3rd for the second fiber coupler mixes bait light
The input of fiber amplifier is connected, and another output end is connected with the one port of optical fiber circulator；
The output end of 3rd EDFA Erbium-Doped Fiber Amplifier is connected with 1550 ports of wavelength division multiplexer, the com of wavelength division multiplexer
Port is connected with the one port of the second photoswitch, 1450 ports of wavelength division multiplexer and the input phase of the first photodetector
Even；
Second photoswitch secondly, thirdly port respectively with the first photoswitch thirdly port and the 3rd photoswitch secondly
Port is connected, and the one port of the 3rd photoswitch is connected with the another port of sensor fibre；
The output end of first photodetector is connected with the one passage of data acquisition unit；
Its Two-port netwerk of optical fiber circulator and the 3rd photoswitch thirdly port is connected, optical fiber circulator thirdly port with
The input of second photodetector is connected, the output end of the second photodetector and data acquisition unit secondly passage is connected,
The output end of data acquisition unit is connected with intelligent apparatus；
Five ports of impulse generator respectively its four port with the first photoswitch, the second photoswitch its four port,
The control terminal of its four ports, the control signal of the second electrooptic modulator and data acquisition unit of the 3rd photoswitch is connected.
Among one embodiment：First photodetector is APD photodetectors, and second photodetector is
PIN photoelectric detector.
Among one embodiment：First photoswitch, the second photoswitch, the 3rd light open the light all to be switched for 1x2.
Among one embodiment：The intelligent apparatus is computer.
Compared with background technology, it has the following advantages that the technical program：
The mode detected using both-end, by Raman sensing measurement temperature, Brillouin sensing measuring strain, realize that temperature should
The two parameter measurement of change；Sensed using the Raman of both-end detection, can reduce the measurement that environmental change is brought influences, and improves system and surveys
Accuracy of measurement and system reliability, the Brillouin sensing detected using both-end, can improve the measuring precision and response speed.
Brief description of the drawings
The utility model is described in further detail with reference to the accompanying drawings and examples.
Fig. 1 is the structural representation of distribution type optical fiber sensing equipment described in the utility model.
Embodiment
Fig. 1, the joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering are refer to, it includes micro-
Ripple signal source 1, Distributed Feedback Laser 2, the first fiber coupler 3, the second fiber coupler 11, first the 4, second electricity of electrooptic modulator
Optical modulator 9, grating filter 5, the first EDFA Erbium-Doped Fiber Amplifier 6, the second EDFA Erbium-Doped Fiber Amplifier 10, the 3rd erbium-doped fiber are put
Big device 12, the first light open the light the 8, second photoswitch 14, the 3rd photoswitch 15, scrambler 7, impulse generator 22, wavelength division multiplexer
13rd, sensor fibre 16, the first photodetector 17, the second photodetector 19, optical fiber circulator 18, data acquisition unit 20 and intelligence
Can device 21；
The output end of Distributed Feedback Laser 2 is connected with the input of the first fiber coupler 3, and the one of the first fiber coupler 3 is defeated
Go out end with a light input end of the first electrooptic modulator 4 to be connected, another output end and a light input end of the second electrooptic modulator 9
It is connected；
The output end of microwave signal source 1 is connected with the rf inputs of the first electrooptic modulator 4, the first electrooptic modulator 4
Output end be connected with the input of grating filter 5, the output end of grating filter 5 and the first EDFA Erbium-Doped Fiber Amplifier 6
Input is connected, and the output end of the first EDFA Erbium-Doped Fiber Amplifier 6 is connected with the input of scrambler 7, the output end of scrambler 7 with
Its Two-port netwerk of first photoswitch 8 is connected, and the one port of the first photoswitch 8 is connected with the one port of sensor fibre 16；It is micro-
Ripple signal source 1 refers to the microwave signal generator for producing that microwave range is 10GHz-12GHz, and the generator can be with 1-5MHz stepping
Speed exports 10GHz-12GHz microwave signal.
The output end of second electrooptic modulator 9 is connected with the input of the second EDFA Erbium-Doped Fiber Amplifier 10, and second mixes bait light
The output end of fiber amplifier 10 is connected with the input of the second fiber coupler 11, an output end of the second fiber coupler 11 with
The input of 3rd EDFA Erbium-Doped Fiber Amplifier 12 is connected, and another output end is connected with the one port of optical fiber circulator 18；
The output end of 3rd EDFA Erbium-Doped Fiber Amplifier 12 is connected with 1550 ports of wavelength division multiplexer 13, wavelength division multiplexer 13
Com ports be connected with the one port of the second photoswitch 14,1450 ports of wavelength division multiplexer 13 and the first photodetector
17 input is connected；
Second photoswitch 14 secondly, thirdly port respectively with the first photoswitch 8 thirdly port and the 3rd photoswitch 15
Its Two-port netwerk be connected, the one port of the 3rd photoswitch 15 is connected with the another port of sensor fibre 16；
The output end of first photodetector 17 is connected with the one passage of data acquisition unit 20；
Its Two-port netwerk of optical fiber circulator 18 and the 3rd photoswitch 15 thirdly port is connected, optical fiber circulator 18 thirdly
Port is connected with the input of the second photodetector 19, the output end of the second photodetector 19 and data acquisition unit 20 its
Two passages are connected, and the output end of data acquisition unit 20 is connected with intelligent apparatus 21；
Five ports of impulse generator 22 respectively its four port with the first photoswitch 8, the second photoswitch 14 its four
Port, its four port of the 3rd photoswitch 15, the control signal of the second electrooptic modulator 9 and the control terminal of data acquisition unit 20
It is connected.
In the present embodiment, first photodetector 17 is APD photodetectors, and second photodetector 19 is
PIN photoelectric detector.
In the present embodiment, first photoswitch 8, the second photoswitch 14, the 3rd light open the light 15 and all switched for 1x2.
The intelligent apparatus 21 is computer, can also be the smart machine of other provided with processor such as notebook computer.
The course of work of distribution type optical fiber sensing equipment described in the present embodiment mainly divides two parts to carry out, and 1, Raman scattering
The acquisition of signal；2nd, the acquisition of Brillouin spectrum.
1st, Raman scattering signal obtains：Distributed Feedback Laser 2 sends continuous laser signal and enters the first fiber coupler 3, and first
Fiber coupler 3 secondly output end enters the second electrooptic modulator 9, work of second electrooptic modulator 9 in impulse generator 22
Under, pulsed optical signals are produced, after being amplified into the second EDFA Erbium-Doped Fiber Amplifier 10, into the second fiber coupler 11,
One delivery outlet of the pulsed optical signals through the second fiber coupler 11 enters the 3rd EDFA Erbium-Doped Fiber Amplifier 12, enters back into wavelength-division and answers
With 1550 ports of device 13, pulsed optical signals enter the second photoswitch 14, impulse generator from the com ports of wavelength division multiplexer 13
22 the first photoswitches 8 of control are switched to thirdly port, the second photoswitch 14 switch to its Two-port netwerk, the 3rd photoswitch 15 switches to
Its Two-port netwerk, pulsed optical signals enter the one end of sensor fibre 16 after the second photoswitch 15, the first photoswitch 8, in sense light
Occur Raman scattering in fibre 16, scattered signal reverse transfer echo division multiplexing device 13, and after being filtered in wavelength division multiplexer 13 by
The output of 1450 ports enters the first photodetector 17, enters back into data acquisition unit 20 and preserves；Then, impulse generator 22 controls
Second photoswitch 14 switches to thirdly port, pulsed optical signals enter sensor fibre through the second photoswitch 14, the 3rd photoswitch 15
16 other ends, Raman scattering occurs in sensor fibre 16, after scattered signal reverse transfer echo division multiplexing device 13 is filtered by
The output of 1450 ports enters the first photodetector 17, enters back into data acquisition unit 20 and preserves.Twice collected above-mentioned
Raman scattering signal can demodulate to obtain the temperature curve of whole piece sensor fibre using formula (1).
2nd, the acquisition of Brillouin spectrum：Distributed Feedback Laser 2 sends continuous laser and is divided into two through the first fiber coupler 3
Road, export to the input of the first electrooptic modulator 4, export all the way to the input of the second electrooptic modulator 9 all the way.First electricity
Optical modulator 4 can produce offset carrier 10GHz-12GHz double-side band, be filtered using grating in the presence of microwave signal source 1
Device 5 can select one of sideband signals, and sideband signals are amplified into the first EDFA Erbium-Doped Fiber Amplifier 6, and by disturbing partially
Device 7 enters the first photoswitch 8, and the first photoswitch 8 is switched under the effect of impulse generator 22 secondly port, sideband signals enter
Sensor fibre 16.The copped wave of continuous laser signal is formed pulsed optical signals by the second electrooptic modulator 9 under impulse generator effect,
It is amplified into the second EDFA Erbium-Doped Fiber Amplifier 10, is then divided into two-way through the second fiber coupler 11, all the way for Raman
Scattered signal obtains (see describing above), and another way enters the 3rd photoswitch 15 by optical fiber circulator 18, in impulse generator
The 3rd photoswitch 15 is switched under 22 effects thirdly port, pulsed optical signals enter sensor fibre 16 and foregoing sideband signals
Stimulated Brillouin scattering effect occurs in sensor fibre 16, sideband signals export through the 3rd photoswitch 15, optical fiber circulator 18
To the second photodetector 19, and gathered through data acquisition unit 20 and preserve signal.Microwave signal source 1 is by 10GHz-12GHz
In the range of frequency sweep carried out with 1-5MHz step frequency, all signals of structure Brillouin spectrum can be obtained, pass through long-range navigation
Hereby fitting can obtain Brillouin spectrum.The strain curve drawn on sensor fibre can be demodulated using formula (2).
Both-end detection Raman diffused light temperature-measurement principle be：
Direct impulse light is opened the light by 1x2 light and switches the both ends of injection sensor fibre, timesharing obtains sensor fibre both ends
The anti-Stokes optical signal come is scattered back, the anti-Stokes optical signal at both ends is subjected to geometric average as flashlight, and
Benchmark is done with Anti-Stokes signal known to sensor fibre temperature, the sensing temperature along whole piece optical fiber can be obtained, demodulates formula
It is as follows：
Wherein, h is planck constant, and k is Boltzmann constant, and Δ ν is the difference on the frequency of Raman diffused light and incident light, PAS
(z, T0) it is annular Anti-Stokes signal, P known to fiber optic temperatureAS(z, T) is the annular Anti-Stokes signal that measures, T0
For the initial temperature of whole piece optical fiber, z is fiber optic temperature induction zone apart from the position of optical fiber incidence end.
Stimulated Brillouin scattering spectrum frequency displacement in optical fiber and the ultrasonic velocity in the effective refractive index and optical fiber of optical fiber have
Close, and ambient temperature and strain all can convert effective refractive index and ultrasonic velocity, be dissipated so as to produce Brillouin
Penetrate spectrum frequency displacement.Therefore, as long as detection Brillouin spectrum frequency displacement can try to achieve temperature or strain on optical fiber.Brillouin spectrum
Frequency displacement and the relation formula of the temperature strain on optical fiber are as follows：
ΔνB=CTΔT+CεΔε (2)
Wherein, Δ vBFor the frequency displacement variable quantity of Brillouin spectrum, Δ T is temperature variation, and Δ ε is stress variation, CT
The temperature coefficient of Brillouin spectrum frequency displacement, CεThe coefficient of strain of Brillouin spectrum frequency displacement.CTAnd CεIt can be measured by experiment,
Because Δ T has been measured by Raman sensor, Δ ε can be obtained by substituting into formula (2) and carrying out simple arrange.
It is described above, only the utility model preferred embodiment, therefore the utility model implementation can not be limited according to this
Scope, i.e., the equivalent changes and modifications made according to the utility model patent scope and description, it is new all should still to belong to this practicality
In the range of type covers.
Claims (4)
1. the joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering, it is characterised in that：Including microwave
Signal source, Distributed Feedback Laser, the first fiber coupler, the second fiber coupler, the first electrooptic modulator, the second electrooptic modulator,
Grating filter, the first EDFA Erbium-Doped Fiber Amplifier, the second EDFA Erbium-Doped Fiber Amplifier, the 3rd EDFA Erbium-Doped Fiber Amplifier, the first light are opened
Light, the second photoswitch, the 3rd photoswitch, scrambler, impulse generator, wavelength division multiplexer, sensor fibre, the first photodetection
Device, the second photodetector, optical fiber circulator, data acquisition unit and intelligent apparatus；
The output end of Distributed Feedback Laser is connected with the input of the first fiber coupler, an output end of the first fiber coupler with
One light input end of the first electrooptic modulator is connected, and another output end is connected with a light input end of the second electrooptic modulator；
The output end of microwave signal source is connected with the rf inputs of the first electrooptic modulator, the output end of the first electrooptic modulator
It is connected with the input of grating filter, the output end of grating filter is connected with the input of the first EDFA Erbium-Doped Fiber Amplifier,
The output end of first EDFA Erbium-Doped Fiber Amplifier is connected with the input of scrambler, the output end of scrambler and the first photoswitch its
Two-port netwerk is connected, and the one port of the first photoswitch is connected with the one port of sensor fibre；
The light output end of second electrooptic modulator is connected with the input of the second EDFA Erbium-Doped Fiber Amplifier, the amplification of the second erbium-doped fiber
The output end of device is connected with the input of the second fiber coupler, an output end and the 3rd erbium-doped fiber of the second fiber coupler
The input of amplifier is connected, and another output end is connected with the one port of optical fiber circulator；
The output end of 3rd EDFA Erbium-Doped Fiber Amplifier is connected with 1550 ports of wavelength division multiplexer, the com ports of wavelength division multiplexer
It is connected with the one port of the second photoswitch, 1450 ports of wavelength division multiplexer are connected with the input of the first photodetector；
Second photoswitch secondly, thirdly port respectively with the first photoswitch thirdly its Two-port netwerk of port and the 3rd photoswitch
It is connected, the one port of the 3rd photoswitch is connected with the another port of sensor fibre；
The output end of first photodetector is connected with the one passage of data acquisition unit；
Its Two-port netwerk of optical fiber circulator and the 3rd photoswitch thirdly port is connected, optical fiber circulator thirdly port and second
The input of photodetector is connected, the output end of the second photodetector and data acquisition unit secondly passage is connected, data
The output end of collector is connected with intelligent apparatus；
Five ports of impulse generator its four port with the first photoswitch, its four ports, 3rd of the second photoswitch respectively
The control terminal of its four ports, the control signal of the second electrooptic modulator and data acquisition unit of photoswitch is connected.
2. the joint Raman of both-end detection according to claim 1 and the distribution type optical fiber sensing equipment of Brillouin scattering,
It is characterized in that：First photodetector is APD photodetectors, and second photodetector is PIN photodetections
Device.
3. the joint Raman of both-end detection according to claim 1 and the distribution type optical fiber sensing equipment of Brillouin scattering,
It is characterized in that：First photoswitch, the second photoswitch, the 3rd light open the light all to be switched for 1x2.
4. the joint Raman of both-end detection according to claim 1 and the distribution type optical fiber sensing equipment of Brillouin scattering,
It is characterized in that：The intelligent apparatus is computer.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107727122A (en) * | 2017-08-14 | 2018-02-23 | 闽南师范大学 | The joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering |
| CN111478164A (en) * | 2020-04-17 | 2020-07-31 | 西北大学 | Self-frequency-sweeping fiber laser based on bidirectional ring cavity |
| CN112781514A (en) * | 2019-11-07 | 2021-05-11 | 中国石油化工股份有限公司 | Method, device and system for detecting abnormal internal pressure deformation of storage tank |
| US20210318182A1 (en) * | 2020-04-13 | 2021-10-14 | Nec Laboratories America, Inc | Distributed fiber optic sensing of temperature using a polarization scrambler |
-
2017
- 2017-08-14 CN CN201721011488.3U patent/CN206974448U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107727122A (en) * | 2017-08-14 | 2018-02-23 | 闽南师范大学 | The joint Raman of both-end detection and the distribution type optical fiber sensing equipment of Brillouin scattering |
| CN112781514A (en) * | 2019-11-07 | 2021-05-11 | 中国石油化工股份有限公司 | Method, device and system for detecting abnormal internal pressure deformation of storage tank |
| US20210318182A1 (en) * | 2020-04-13 | 2021-10-14 | Nec Laboratories America, Inc | Distributed fiber optic sensing of temperature using a polarization scrambler |
| CN111478164A (en) * | 2020-04-17 | 2020-07-31 | 西北大学 | Self-frequency-sweeping fiber laser based on bidirectional ring cavity |
| CN111478164B (en) * | 2020-04-17 | 2021-01-01 | 西北大学 | Self-frequency-sweeping fiber laser based on bidirectional ring cavity |
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