CN106840358A - A kind of method for increasing distributed optical fiber vibration sensing system detection range - Google Patents
A kind of method for increasing distributed optical fiber vibration sensing system detection range Download PDFInfo
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- CN106840358A CN106840358A CN201611266607.XA CN201611266607A CN106840358A CN 106840358 A CN106840358 A CN 106840358A CN 201611266607 A CN201611266607 A CN 201611266607A CN 106840358 A CN106840358 A CN 106840358A
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- optical fiber
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- vibration sensing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
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Abstract
The present invention discloses a kind of method for increasing distributed optical fiber vibration sensing system detection range, distributed optical fiber vibration sensing system includes the continuous wave laser source being sequentially connected, acousto-optic modulator, erbium-doped fiber amplifier, wave filter, the output end of the wave filter is connected with a shunt, two output ends of the shunt connect a detection channels respectively, it is characterized in that adding a raman amplifier in the light path of each passage, the raman amplifier is connected with an input of wave multiplexer, external 40 ~ 60 kilometers of test optical fibre cables long of another input of wave multiplexer, the output end of wave multiplexer connects the signal processing circuit of detection channels by circulator.The advantage of the invention is that raman amplifier is integrated into original DVS systems, the effective detection range of system is significantly improved；So as to reduce equipment cost, and construction and maintenance cost.
Description
Technical field
The present invention relates to distributed optical fiber vibration sensing system, more particularly to a kind of increase distributed optical fiber vibration sensing system
The method of system detection range.
Background technology
Distributed optical fiber vibration sensing system（DVS）Based on the optical time domain reflection with phase information（Ф-OTDR）Technology, with
G652 single-mode fibers are sensor information.The pulse laser of laser transmitting narrow linewidth is transmitted along sensor fibre, while constantly producing
The Rayleigh scattering light for transmitting backward, and there is multiple-beam interference in these Rayleigh scattering lights.When sensor fibre is vibrated by the external world
During interference, Rayleigh scattering light phase dorsad can change, and cause the intensity distribution of multiple-beam interference to change.Photoelectricity
Conversion equipment detects the change of these interference light intensities distribution, and is demodulated into vibration signal.Here it is DVS can detect the external world shaking
Dynamic the reason for.
Can gradually decay when pulse laser is along Optical Fiber Transmission, cause the Rayleigh scattering luminous intensity for returning to increase with transmission range
And gradually weaken.When transmission range increases to a limiting value, the Rayleigh scattering luminous intensity of return is very faint, so that it cannot
Distinguished with ambient noise, then the vibration signal of this distance cannot be detected.Therefore, the list of the like product in current industry
Passage effective detection range is substantially all within 25 kilometers.
And for some on a large scale, the engineering project of long range, this effective detection range be difficult to meet application.
The content of the invention
The technical problems to be solved by the invention are to provide a kind of increase distributed optical fiber vibration sensing system detection range
Method, by raman amplifier in optical fiber transmit light signal strength do distributed air-defense, with the biography of this compensated optical signal
Defeated decay, so as to increase the effective detection range of DVS.
In order to solve the problems, such as appeal, the present invention is achieved by the following scheme：One kind increases distributed optical fiber vibration and passes
The method of sensing system detection range, distributed optical fiber vibration sensing system includes that the continuous wave laser source being sequentially connected, acousto-optic are adjusted
Device processed, erbium-doped fiber amplifier, wave filter, the output end of the wave filter are connected with a shunt, two of the shunt
Output end connects a detection channels respectively, it is characterised in that a raman amplifier, institute are added in the light path of each passage
State raman amplifier to be connected with an input of wave multiplexer, external 40 ~ 60 kilometers of tests long of another input of wave multiplexer
Optical cable, the output end of wave multiplexer connects the signal processing circuit of detection channels by circulator.
According to a preferred embodiment of the invention, the first end of the circulator is connected with shunt, the second end of circulator
Be connected with the output end of wave multiplexer, the 3rd end of circulator then successively with erbium-doped fiber amplifier, wave filter, adjustable optical attenuator
Module and APD circuits are connected.
According to a preferred embodiment of the invention, the length of the test optical fibre cables is preferably 40 ~ 50km.
Be fused to raman amplifier in sensor fibre by wave multiplexer by the present invention, because of stimulated Raman scattering and incident light
Transmission direction is unrelated, therefore the pulse laser and reverse Rayleigh scattering light in sensor fibre all obtain distributed air-defense.The present invention is logical
Cross raman amplifier and distributed air-defense is done to the light signal strength transmitted in optical fiber, with the transmission attenuation of this compensated optical signal, from
And increase the effective detection range of DVS.In the engineering project of long range（Such as anti-intrusion along oil pipeline, high ferro）Using when,
The detection range of single DVS is bigger, and the DVS host numbers of requirement of engineering are fewer.So as to reduce equipment cost, and construction
And maintenance cost.
The advantage of the invention is that raman amplifier is integrated into original DVS systems, the effective of system is significantly improved
Detection range；Raman amplifier is modular, it is easy to integrated, and system other parts keep constant, thus change cost is small,
Technical risk is low；Optical system after improvement does distributed air-defense to flashlight, contribute to suppress optical fiber in it is various non-linear
Effect, so as to improve the signal to noise ratio of system.
Brief description of the drawings
Fig. 1 is Raman amplifier structure schematic diagram.
Fig. 2 is the DVS optical structure charts after the present invention is improved.
Fig. 3 is the vibration signal figure detected when DVS does not have integrated raman amplifier.
Fig. 4 is the vibration signal figure detected after the integrated raman amplifiers of DVS.
Specific embodiment
The main composition of raman amplifier has：High power semi-conductor pump light source (LD), wave multiplexer (WDM), isolator
(ISO) etc..Fig. 1 is Raman amplifier structure schematic diagram.The raman amplifier includes the first wave multiplexer, first wave multiplexer
Input be connected with the output end of several high power semi-conductor pump light sources, the output end of the first wave multiplexer and the second multiplex
The input connection of device, the input of the second wave multiplexer is connected with fiber-optic signal input, and the output end of the second wave multiplexer is letter
Number output end, the fiber-optic signal input is additionally provided with isolator.
In optical medium, sub-fraction incident power is transferred to another longer wavelengths of light by the shorter pump light of wavelength
Beam, the difference of the two wavelength is determined that this process is referred to as stimulated raman scattering by the vibration mode of medium.In quantum mechanics
In, it is another low frequency photon that this process can be described as a photon of incident light wave by medium molecule scattering, referred to as this
The frequency displacement light of lentor ripple (Stokes), remaining energy is by medium with molecular vibration（Optical phonon）Form absorb, complete
Transition between vibrational state.Or one phonon of a photonic absorption, produce another high frequency photon, referred to as anti-Stokes light
Ripple (anti-Stokes).
Raman amplifier utilizes stimulated raman scattering, and the part energy of the shorter pump light of wavelength is transferred into light
The flashlight transmitted in fibre, to offset the signal optical attenuation that optical fiber is caused in itself.
Raman amplifier with Transmission Fibers as gain media, to flashlight distributed air-defense, with simple structure, Yi Yuxian
Have the advantages that system is blended.With erbium-doped fiber amplifier（EDFA）Concentrate amplification form different etc. discrete, distributed air-defense
The various non-linear phenomenas in optical fiber can to greatest extent be suppressed, system noise is reduced.
Fig. 2 is a kind of distributed optical fiber vibration sensing system for increasing detection range, distributed optical fiber vibration sensing
System includes the continuous wave laser source 1, acousto-optic modulator 2, erbium-doped fiber amplifier 3, the first wave filter 4 that are sequentially connected, described
The output end of the first wave filter 4 and a shunt 5（The shunt is 50:50 shunts）Connection, two of the shunt 5 are defeated
Go out end and connect a detection channels respectively, it is characterised in that a raman amplifier 8 is added in the light path of each passage, it is described
Raman amplifier 8 is connected with an input of wave multiplexer 7, external 40 ~ 60 kilometers of tests long of another input of wave multiplexer 7
Optical cable 9, the output end of wave multiplexer 7 connects the signal processing circuit of detection channels by circulator 6.
According to a preferred embodiment of the invention, the first end of the circulator 6 is connected with shunt 7, and the second of circulator 6
End is connected with the output end of wave multiplexer 7, the 3rd end of circulator 6 then successively with erbium-doped fiber amplifier 10, wave filter 11, adjustable
Optical attenuator module 12 and APD circuits 13 are connected.
APD is avalanche photodide, and each module being related in the present invention is prior art, be will not be repeated here.
Be fused to raman amplifier in sensor fibre by wave multiplexer by the present invention, because of stimulated Raman scattering and incident light
Transmission direction is unrelated, therefore the pulse laser and reverse Rayleigh scattering light in sensor fibre all obtain distributed air-defense.
Before and after integrated raman amplifier, following test is done to DVS systems：Single channel accesses nearly 41 kilometers of a roll long
Sensor fibre（Bare fibre）, gently pat this roll of sensor fibre, then 41 kilometers of scopes long of whole passage all generate vibration,
Vibration signal is observed with DVS software kits（Energy curve figure）.
Fig. 3 shows the vibration signal of the whole passage when not having integrated raman amplifier（Spatial resolution is in figure
10m/Point, therefore 4000 Points correspondence length distances are 40 kilometers）, it can be seen that DVS is detected and believed compared with the vibration of distal end
It is number very faint.In this case, the intrusion event of distal end is difficult to be detected.
Fig. 4 shown under the conditions of same test, the vibration letter detected after DVS system integrations raman amplifier
Number.Comparison diagram 3 can see, and now the vibration signal of distal end has and significantly increases, and illustrates flashlight at whole 41 kilometers long
Substantially do not weaken when being transmitted in optical fiber, i.e., raman amplifier compensate for the decay that optical fiber is caused.In this case, system is held very much
Easily detect the intrusion event of channel distal end generation.
Above content is to combine specific preferred embodiment further description made for the present invention, it is impossible to assert
Present invention specific implementation is confined to above-mentioned these explanations.For general technical staff of the technical field of the invention,
Without departing from the inventive concept of the premise, some simple deduction or replace can also be made, the present invention should be all considered as belonging to
Protection domain.
Claims (2)
1. it is a kind of increase distributed optical fiber vibration sensing system detection range method, distributed optical fiber vibration sensing system bag
Include continuous wave laser source, acousto-optic modulator, erbium-doped fiber amplifier, the wave filter being sequentially connected, the output end of the wave filter
It is connected with a shunt, two output ends of the shunt connect a detection channels respectively, it is characterised in that each passage
Light path in add a raman amplifier, the raman amplifier is connected with an input of wave multiplexer, wave multiplexer
Another external 40 ~ 60 kilometers of test optical fibre cables long of input, the output end of wave multiplexer connects the letter of detection channels by circulator
Number process circuit.
2. the method for increasing distributed optical fiber vibration sensing system detection range as claimed in claim 1, it is characterised in that institute
The first end for stating circulator is connected with shunt, and the second end of circulator is connected with the output end of wave multiplexer, and the 3rd of circulator the
End is then connected with erbium-doped fiber amplifier, wave filter, adjustable optical attenuator module and APD circuits successively.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020060839A1 (en) * | 2000-11-21 | 2002-05-23 | Wang-Yuhl Oh | Hybrid fiber amplifier using dispersion compensating raman amplifier |
| US20030169479A1 (en) * | 2002-03-11 | 2003-09-11 | Lucent Technologies | Method and apparatus for achieving flat broadband raman gain |
| CN101893476A (en) * | 2010-03-11 | 2010-11-24 | 上海华魏光纤传感技术有限公司 | Long-distance optical fiber vibration sensing system with distributed amplification |
| CN102506912A (en) * | 2011-09-29 | 2012-06-20 | 北京航空航天大学 | Optical fiber distributed disturbance sensor |
| CN102706437A (en) * | 2012-06-13 | 2012-10-03 | 扬州森斯光电科技有限公司 | Super-long distance phase-sensitive optical time domain reflectometer (Phi-OTDR) system |
| CN104266742A (en) * | 2014-10-22 | 2015-01-07 | 威海北洋光电信息技术股份公司 | High-target distribution type optical fiber vibration sensor |
| CN104700624A (en) * | 2015-03-16 | 2015-06-10 | 电子科技大学 | Traffic flow online monitoring system and method based on phase-sensitive optical time domain reflectometer |
-
2016
- 2016-12-31 CN CN201611266607.XA patent/CN106840358A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020060839A1 (en) * | 2000-11-21 | 2002-05-23 | Wang-Yuhl Oh | Hybrid fiber amplifier using dispersion compensating raman amplifier |
| US20030169479A1 (en) * | 2002-03-11 | 2003-09-11 | Lucent Technologies | Method and apparatus for achieving flat broadband raman gain |
| CN101893476A (en) * | 2010-03-11 | 2010-11-24 | 上海华魏光纤传感技术有限公司 | Long-distance optical fiber vibration sensing system with distributed amplification |
| CN102506912A (en) * | 2011-09-29 | 2012-06-20 | 北京航空航天大学 | Optical fiber distributed disturbance sensor |
| CN102706437A (en) * | 2012-06-13 | 2012-10-03 | 扬州森斯光电科技有限公司 | Super-long distance phase-sensitive optical time domain reflectometer (Phi-OTDR) system |
| CN104266742A (en) * | 2014-10-22 | 2015-01-07 | 威海北洋光电信息技术股份公司 | High-target distribution type optical fiber vibration sensor |
| CN104700624A (en) * | 2015-03-16 | 2015-06-10 | 电子科技大学 | Traffic flow online monitoring system and method based on phase-sensitive optical time domain reflectometer |
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