CN107289978A - A kind of system and method for the survey disturbance based on POTDR - Google Patents
A kind of system and method for the survey disturbance based on POTDR Download PDFInfo
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- CN107289978A CN107289978A CN201710431761.6A CN201710431761A CN107289978A CN 107289978 A CN107289978 A CN 107289978A CN 201710431761 A CN201710431761 A CN 201710431761A CN 107289978 A CN107289978 A CN 107289978A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
Abstract
The invention discloses a kind of system of the survey disturbance based on POTDR, by introducing a polarization beam apparatus and a polarization beam combiner, direct impulse is first divided into two equal orthogonal polarization components of energy, it is synthesized together again after a small amount of delay, the direct impulse light of synthesis enters analyzer through circulator after the transmission of connection optical fiber.Analyzer is arranged on the front end of sensor fibre, and direct impulse will enter avalanche probe by circulator and the polarization signal along optical fiber is sensed by signal analysis by entering back into optical fiber, the back rayleigh scattering light of optical fiber after analyzer.By introducing the connection optical fiber of coupler and different length, measured while can be achieved to being disturbed in multi-channel optical fibre.The invention also discloses a kind of survey perturbation motion method based on POTDR, the present invention eliminates POTDR systems with connecting influence of the unrelated disturbance to sensing detection on optical fiber, strong antijamming capability between sensor fibre；By multiplexing, the system can detect the disturbance in multiple separate regions simultaneously.
Description
Technical field
The present invention relates to technical field of optical fiber sensing, the system and method for particularly a kind of survey disturbance based on POTDR.
Background technology
Optical fiber sensing technology is the brand-new technology developed from 1970s, with the reality of optical fiber
With the development changed with optical communication technique, optical fiber sensing technology is with the posture fast development of diversification.When light is transmitted in a fiber,
Because optical fiber is influenceed by environmental factors such as external disturbance, temperature, strain, displacements, polarization state, power, wavelength, the phase of optical signal
The parameters such as position can change.Pass through these parameters of light in detection fiber, it is possible to obtain the change letter of optical fiber surrounding environment
Breath, so as to realize sensing.
When a branch of short light pulse incides optical fiber, it is along spread fiber and is dispersed into all directions, and a part dissipates
Penetrate light to transmit along optical fiber and return to incidence end, this some scattered light is referred to as back rayleigh scattering light, back rayleigh scattering light
Carry the information disturbed along sensor fibre.Optical time domain sensing technology based on Rayleigh scattering is exactly by monitoring in optical fiber
The characteristic of back rayleigh scattering light realizes a kind of sensing technology of distributed sensing.
Polarized light time domain reflection technology is exactly to realize one kind of sensing by detecting the polarization state of back rayleigh scattering light
Optical time domain reflection technology.1980, Rogers proposed polarized light time domain reflection technology (POTDR) thought.Laser is sent
Light modulated by acousto-optic modulator after be changed into pulsed light, it is incident by circulator after being amplified to certain power through erbium-doped fiber amplifier
To testing fiber, the back rayleigh scattering light in transmitting procedure is returned by circulator, by after polarization beam apparatus analyzing by photoelectricity
Detector is received.When optical fiber is by external disturbance, the polarization state of light will change in optical fiber.Simultaneously as light pulse exists
Back rayleigh scattering occurs when being transmitted in optical fiber, therefore the change of back rayleigh scattering polarization state is detected by detector, just
The information that optical fiber is disturbed can be obtained.
Because the polarization state of light in optical fiber can produce change with outside to the disturbance of POTDR connection optical fiber, so POTDR
The less stable of system, and light when transmitting in a fiber, the change of polarization state is with successional, if connection optical fiber is thanksed for your hospitality
Dynamic, the Rayleigh scattering signal passed back from testing fiber will be blanked, and the accuracy of sensing will be affected.Traditional POTDR
There is the defect of poor anti jamming capability in sensing technology.It is a need in POTDR sensor-based systems so how to improve antijamming capability
The problem for wanting emphasis to solve.
The content of the invention
The technical problems to be solved by the invention are to overcome the deficiencies in the prior art and provide a kind of survey based on POTDR and disturb
Dynamic system and method, the present invention improves the antijamming capability and long-range measurement capability of POTDR systems.
The present invention uses following technical scheme to solve above-mentioned technical problem：
According to it is proposed by the present invention it is a kind of based on POTDR survey disturbance system, including laser module, Polarization Controller,
Polarization beam apparatus, polarization maintaining optical fibre, polarization beam combiner, circulator, connection optical fiber, analyzer, avalanche photodetector, capture card and
Processor；Wherein,
Laser module, for the pulsed light of the complete polarization of output to be exported to polarization beam apparatus through Polarization Controller；
Polarization beam apparatus, for the control through Polarization Controller, output two-way polarization state is mutually orthogonal and power is equal
Pulsed light；Wherein, all the way pulse light output to polarization beam combiner；Another road pulsed light is exported to polarization coupling through polarization maintaining optical fibre
Device；
Polarization beam combiner, for the two-way received pulsed light to be synthesized, the pulsed light after synthesis is through circulator, company
Connect and exported after optical fiber, analyzer to outside sensor fibre, the pulsed light exported by analyzer transmits generation in sensor fibre
Back rayleigh scattering light reversely again by being exported after analyzer through circulator to avalanche photodetector；
Avalanche photodetector, is extremely gathered for the back rayleigh scattering received light to be converted into output after electric signal
Card；
Capture card, for the electric signal output of collection to processor to be analyzed and processed, so as to obtain sensor fibre edge
The destabilization sensing information of line.
It is used as a kind of further prioritization scheme of system of the survey disturbance based on POTDR of the present invention, the mode of laser
Block includes pulse laser and the polarizer；Wherein,
Pulse laser, for output optical pulse to the polarizer；
The polarizer, for ensureing pulsed light by thereafter, export the pulsed light that polarizes completely through Polarization Controller export to
Polarization beam apparatus.
Based on a kind of method of above-mentioned survey perturbed system based on POTDR, comprise the following steps：
Step (1), to sensor fibre injected pulse light at the same time, processor persistently receives multigroup dorsad auspicious
Sharp scattered light signal, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step (2), to obtained in step (1) it is average after back rayleigh scattering optical signal, enter using by adjacent signals
The mode of row difference realizes the positioning to disturbance point；
Step (3), by obtained in step (1) it is average after back rayleigh scattering optical signal, using the side of spectrum analysis
Method is measured to the frequency of disturbing signal and position.
A kind of system of the survey disturbance based on POTDR, including laser module, Polarization Controller, polarization beam apparatus, polarization-maintaining light
Fibre, polarization beam combiner, circulator, 1 × N couplers, multiple connection optical fiber, multiple analyzers, avalanche photodetector, capture card
And processor；One end of connection optical fiber is connected one by one respectively with the output end of 1 × N couplers, connects the other end and the inspection of optical fiber
Inclined device is connected one by one respectively, and the number of connection optical fiber and analyzer is N, and N is the integer more than 1, and the length for connecting optical fiber is equal
It is different；Wherein,
Laser module, for the pulsed light of the complete polarization of output to be exported to polarization beam apparatus through Polarization Controller；
Polarization beam apparatus, for the control through Polarization Controller, output two-way polarization state is mutually orthogonal and power is equal
Pulsed light；Wherein, all the way pulse light output to polarization beam combiner；Another road pulsed light is exported to polarization coupling through polarization maintaining optical fibre
Device；
Polarization beam combiner, for the two-way received pulsed light to be synthesized, the pulsed light after synthesis is through circulator, 1
After × N couplers, output N roads light passes through connection optical fiber, the analyzer being connected respectively with the output end of 1 × N couplers successively respectively
Export afterwards to outside multiple sensor fibres, the pulsed light exported by analyzer transmits the dorsad Rayleigh produced in sensor fibre
Scattered light after analyzer through circulator reversely again by exporting to avalanche photodetector；Each sensor fibre is produced dorsad
Rayleigh scattering light staggers in time domain；
Avalanche photodetector, is exported to capture card for back rayleigh scattering light to be converted to after electric signal；
Capture card, for the electric signal output of collection to processor to be analyzed and processed, so as to realize to multiple sensings
Measured while destabilization sensing information along optical fiber.
It is used as a kind of further prioritization scheme of system of the survey disturbance based on POTDR of the present invention, the mode of laser
Block includes pulse laser and the polarizer；Wherein,
Pulse laser, for output optical pulse to the polarizer；
The polarizer, for ensureing pulsed light by thereafter, export the pulsed light that polarizes completely through Polarization Controller export to
Polarization beam apparatus.
As a kind of further prioritization scheme of system of the survey disturbance based on POTDR of the present invention, each road is multiplexed
Signal staggers in time domain, does not interfere with each other mutually, before being more than or equal to per the length of connection optical fiber all the way in multiplexing structure
Connection optical fiber all the way and sensor fibre length sum.
Based on a kind of method of above-mentioned survey perturbed system based on POTDR, comprise the following steps：
Step (1), to sensor fibre injected pulse light at the same time, processor persistently receives multigroup dorsad auspicious
Sharp scattered light signal, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step (2), to obtained in step (1) it is average after back rayleigh scattering optical signal, it is poor that adjacent signals are carried out
The mode divided realizes the positioning to disturbance point；
Step (3), by obtained in step (1) it is average after back rayleigh scattering optical signal, using the side of spectrum analysis
Method is measured to the frequency of disturbing signal and position.
A kind of survey perturbation motion method based on POTDR, comprises the following steps：
Step 1: the pulsed light that two-way polarization state is mutually orthogonal and power is equal is synthesized；
Step 2: the pulsed light after synthesis is exported to outside sensor fibre after circulator, connection optical fiber, analyzer,
The pulsed light exported by analyzer transmitted in sensor fibre generation back rayleigh scattering light reversely again by analyzer after
Exported through circulator to receiving terminal；
Step 3: to sensor fibre injected pulse light at the same time, receiving terminal persistently receives multigroup dorsad auspicious
Sharp scattered light signal, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step 4: to obtained in step 3 it is average after back rayleigh scattering optical signal, difference is carried out to adjacent signals
Mode realize positioning to disturbance point；
Step 5: by obtained in step 3 it is average after back rayleigh scattering optical signal, using the method for spectrum analysis
Frequency and position to disturbing signal are measured.
A kind of survey perturbation motion method based on POTDR, comprises the following steps：
Step 1: the pulsed light that two-way polarization state is mutually orthogonal and power is equal is synthesized；
Step 2: the pulsed light after synthesis is after circulator, 1 × N couplers, output N roads light is passed through and 1 × N successively respectively
The connection optical fiber of the output end connection of coupler, export to multiple sensor fibres of outside after analyzer, exported by analyzer
Pulsed light transmitted in sensor fibre generation back rayleigh scattering light reversely again by after analyzer through circulator export to
Receiving terminal；The number for connecting optical fiber and analyzer is N, and one end of connection optical fiber and the output end difference of 1 × N couplers are one by one
Connection, the other end of connection optical fiber is connected one by one respectively with analyzer, and N is the integer more than 1, connects the length of optical fiber not
Together, the back rayleigh scattering light that each sensor fibre is produced staggers in time domain；
Step 3: to sensor fibre injected pulse light at the same time, receiving terminal persistently receives multigroup dorsad auspicious
Sharp scattered light signal, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step 4: to obtained in step 3 it is average after back rayleigh scattering optical signal, difference is carried out to adjacent signals
Mode realize positioning to disturbance point；
Step 5: by obtained in step 3 it is average after back rayleigh scattering optical signal, using the method for spectrum analysis
Frequency and position to disturbing signal are measured.
As a kind of further prioritization scheme of survey perturbation motion method based on POTDR of the present invention, the letter on each road is multiplexed
Number stagger in time domain, do not interfere with each other mutually, be more than or equal to per the length of connection optical fiber all the way previous in multiplexing structure
The connection optical fiber and sensor fibre length sum on road.
The present invention uses above technical scheme compared with prior art, with following technique effect：
(1) in the present invention circulator between polarization beam combiner and analyzer and optical fiber is connected when by external disturbance,
Influence will not be produced on transducing signal, greatly improve the antijamming capability and long-range measurement capability of POTDR systems；
(2) present invention can carry out distributed measurement in the disturbance of optional position on testing fiber, recognize its forcing frequency
And positioned；
(3) multiplexing can also be realized by coupler, non-interfering point can be carried out simultaneously to multiple isolated areas
Cloth sensing measurement.
Brief description of the drawings
Fig. 1 is the experimental rig figure of the present invention.
Fig. 2 is spectrogram of the 2 points of vibration POTDR transducing signals of experiment collection after Fourier transformation.
The spectrogram after POTDR transducing signal Fourier transformations when Fig. 3 is to connection optical fiber addition disturbance.
Fig. 4 is the two-way multiplexing Experimental equipment for introducing a three-dB coupler.
Fig. 5 a are that two-way is multiplexed the time-domain diagram at the second road sensor fibre 540m plus vibrated.
Fig. 5 b are that two-way is multiplexed the difference time domain figure at the second road sensor fibre 540m plus vibrated.
Fig. 6 is that two-way multiplexing two-way adds the spectrogram after the POTDR transducing signal Fourier transformations of vibration respectively.
Embodiment
Technical scheme is described in further detail below in conjunction with the accompanying drawings：
As shown in figure 1, the sensor-based system of the survey disturbance based on POTDR includes：Pulse laser, the polarizer, Polarization Control
Device, polarization beam apparatus, polarization maintaining optical fibre, polarization beam combiner, circulator, connection optical fiber analyzer, avalanche photodetector and collection
Card；The output of pulse laser connects the polarizer, then by Polarization Controller, two-way, first are divided into after polarization beam apparatus
Road is led directly to, and the second tunnel connects an elongated segment polarization-maintaining wire jumper, and two-way synthesizes light all the way by a polarization beam combiner again afterwards, into ring
The port of shape device 1, the port of circulator 2 connects analyzer and enters back into testing fiber, back rayleigh scattering light return again by analyzer and
The port of circulator 2, enters avalanche photodetector from the port outgoing of circulator 3, and gathering back rayleigh scattering light by capture card believes
Number, reach PC and do signal analysis, obtain the heat transfer agent along optical fiber.In addition when pulse laser exports for complete polarization-maintaining
When, it is convenient to omit the polarizer.The testing fiber is sensor fibre.
Further, the device of multiplexing needs to insert coupler behind the Two-port netwerk of circulator, as shown in Figure 4
Schematic device, by inserting coupler behind 2 ports of circulator, makes POTDR systems have multiple output same components
Port, then by adding the connection optical fiber of a segment length before each road sensor fibre of multiplexing, each section of transducing signal can be made to exist
Stagger in time domain, so as to realize multiplexing, detect the different disturbances in multiple separate regions.Disturbance is surveyed based on POTDR
Multiplexing sensor-based system includes：Pulse laser, the polarizer, Polarization Controller, polarization beam apparatus, polarization-maintaining wire jumper, polarization are closed
Beam device, circulator, coupler, the first connection optical fiber, the first analyzer, the second connection optical fiber, the second analyzer, avalanche optoelectronic are visited
Survey device and capture card.
Pulse laser sends light pulse, by the polarizer, it is ensured that the light after the polarizer is complete polarized light, afterwards
It is divided into the mutually orthogonal pulse of two-way polarization state by a Polarization Controller, then by a polarization beam apparatus afterpulse light
Light, wherein leading directly to all the way, line delay is entered in another road by a bit of polarization maintaining optical fibre, and two-way light is by a polarization beam combiner afterwards
Synthesized, the pulsed light after synthesis is transmitted to the analyzing positioned at testing fiber front end after circulator by connecting optical fiber
Device, after an analyzer, pulsed light transmits the back rayleigh scattering light of generation reversely again by inspection in testing fiber
Enter avalanche photodetector (APD) through circulator after inclined device, received by avalanche photodetector, then carried out via capture card
Electrical signal collection.
Polarization state into the light pulse for injecting polarization beam apparatus is controlled by adjusting the Polarization Controller before polarization beam apparatus,
Make the two-way light of the polarization beam apparatus power before closing light equal.Even if by this way, circulator and connection optical fiber are disturbed
The polarization state of wherein light wave, energy and polarization state of the composite pulse light when entering testing fiber by analyzer are changed after dynamic
Remain constant, the antijamming capability of POTDR sensor-based systems can be greatly improved.When sensor fibre to be measured is by external disturbance
When, the polarization state of light will change in optical fiber.Meanwhile, the intensity of the back rayleigh scattering light returned through analyzer can become
Change, therefore the change of back rayleigh scattering polarization state in testing fiber can be detected by detector, treated so as to realize
The sensing of the upper disturbance event of light-metering fibre.
The above method is characterized by, and the conjunction pulsed light that two mutually orthogonal and the equal pulse of energy is synthesized is in warp
Cross after analyzer, can guarantee that connection optical fiber is subjected to gross energy and polarization direction during disturbance and keeps constant, its principle is as follows.
Assuming that incident pulse luminous intensity is I0, can be expressed as with Jones vectorWherein ν0
It is the frequency of light wave, two-way pulsed light of the pulsed light after PBS light splitting is linearly polarized light, and its polarization state is orthogonal.
E is wherein designated as all the way1, its Jones vector is expressed asAnother road we be designated as E2, Jones vector
It is expressed asE2With E1Orthogonal, energy is equal.The connection optical fiber for connecting circulator and analyzer can
To be regarded as one section of wave plate, its transmission matrix is designated as
φ is the phase shift of wave plate in the transmission matrix, and α is the anglec of rotation of wave plate.The transmission matrix of analyzer is expressed asWherein β is the azimuth of analyzer.Two-way output light can be expressed as Eout1
=JPJRE1, Eout2=JPJRE2.Delay polarization maintaining optical fibre in PBS can make two pulses produce time delay in time domain to stagger, due to
The coherence length of direct impulse is generally less than 1cm in POTDR, to be much smaller than the length of delay polarization maintaining optical fibre, therefore Eout1And Eout2
It is orthogonal, be by the total light intensity I after analyzerWhereinRepresent multiple
Conjugation, it can be found that its value is equal to the half into the pulse luminous power for injecting PBS, it is unrelated with the transmission matrix for connecting optical fiber, and
Polarization direction is consistent with the direction of the light transmission shaft of analyzer, is linearly polarized light.Therefore by the POTDR systems of the present invention, when
Connection optical fiber between POTDR systems and analyzer will not produce influence when by external disturbance on transducing signal, so as to
To improve the jamproof abilities of POTDR.
The course of work of the present invention is as follows：
Step one：Using system as shown in Figure 1,10000 groups of light pulses that time interval is 100us are sent by laser
Signal, pulsewidth is 20ns, by the polarizer, then by Polarization Controller, is divided into two-way light by polarization beam apparatus, wherein polarization point
Two ports of beam device are designated as port 1 and port 2 respectively, and one section of 2m delay polarization maintaining optical fibre is passed through in port 1, and port 2 is led directly to, and two
It is combined into all the way via a polarization beam combiner again after the light of road.Because the separated two-way light state of polarization beam apparatus is mutually orthogonal, because
This allows to keep the process analyzer after closing light to enter sensing to be measured during internal be disturbed to reach expected experiment effect
The pulsed light gross energy of optical fiber and polarization direction keep constant, and it is equal that we only need to adjust two-way luminous power.Specific practice is：It is first
First polarization beam apparatus port 1 and polarization beam combiner are disconnected, port 2 keeps being connected with polarization beam combiner, is monitored with power meter single
Road light is in the power after polarization beam combiner and is recorded as W1；Polarization beam apparatus port 2 and polarization beam combiner are disconnected again, end
Mouth 1 keeps being connected with polarization beam combiner, and with power meter monitoring, single channel light is in the power after polarization beam combiner and is recorded as W2.
The Polarization Controller of polarization beam apparatus front end is adjusted, W1 and W2 power can be adjusted, when both power are equal, now polarization divides
The two-way light that beam device divides is mutually orthogonal and power is equal.Via the light after polarization beam combiner closing light via circulator,
Back rayleigh scattering light is produced by entering sensor fibre to be measured after analyzer, back rayleigh scattering light can be passed back by circulator
APD, after APD is changed, into capture card, 10000 groups of POTDR signals are adopted to obtain by capture card.According toBetween time
It is more than light pulse every T and comes and goes optical fiber required time, fsFor default peak frequency.This 10000 groups of signals are abandoned every after 40 groups
166 groups are done average, 60 groups of signals after being averaged.
Step 2：By obtain it is average after 25 groups of signals be sequentially arranged and the alignment of opsition dependent information, can obtain
Changed with time (time interval of change is nT) to the back rayleigh scattering optical signal each put, by each position with the time
The signal of change carries out Fourier transformation processing, and seeks power spectrum, can obtain the back rayleigh scattering light each put on optical fiber
The frequency spectrum of signal.Diverse location applies vibration at sensor fibre two to be measured respectively, is operated according to experimental procedure one, two, can be with
Obtain frequency spectrum as shown in Figure 2.It is respectively 1000m and 2000m, 1000m that can be analyzed from frequency spectrum and show that vibration applies position
It is 15Hz or so that place, which applies vibration frequency, and the vibration frequency applied at 2000m is 10Hz or so.
Step 3：Connection optical fiber apply 10Hz vibration, while extrude analyzer tail optical fiber, simulation connection optical fiber by
The situation of disturbance, and the operation of repeat step one, and averaged curve is done into Fourier transformation processing, try to achieve power spectrum such as Fig. 3 institutes
Show, it can be found that the disturbance of connection optical fiber does not produce influence on result of detection, spectrogram can't be because of the vibration for connecting optical fiber
Or extruding changes, this means that the disturbance rejection effect of this experimental method is fairly obvious.
Step 4：On this basis, by inserting a 1*2 coupler behind the Two-port netwerk of circulator, POTDR systems are made
System has the port of two output same components, and the first via connects 1km sensor fibre, and the second tunnel first passes through 1km connection optical fiber,
Two sections of transducing signals is staggered in time domain, reconnect one section of 1km sensor fibre, realize that two-way is multiplexed.Sent by laser
Time interval is 100us 10000 groups of light pulse signals, and pulsewidth is 20ns, by the polarizer, then by Polarization Controller, by
Polarization beam apparatus is divided into two-way light, and wherein the two of polarization beam apparatus port is designated as port 1 and port 2 respectively, and port 1 passes through one
Section 2m delay polarization maintaining optical fibre, port 2 leads directly to, is combined into all the way via a polarization beam combiner again after two-way light.Adjust PBS points
The two-way luminous power of light is equal, and every 166 groups of 10000 groups of signals of collection do average, 60 groups of signals after being averaged.Multiple
Second road sensor fibre addition vibration, gets difference time domain figure it can be seen that disturbance point by being made the difference between 60 groups of signals
Position.Fig. 5 a are the one group of signal taken out at random from 60 groups of signals, and preceding 1000m signal is the transducing signal of the first via,
It is the transducing signal on the second tunnel at 1000m~2000m, two paths of signals is not interfere with each other mutually.Fig. 5 b are then difference time domain signals, from figure
In can obtain at the sensor fibre 540m of the position of disturbance point for the second tunnel of multiplexing.
Step 5：According to the operation of step 4,25 groups of signals after being averaged are sequentially arranged and step-by-step confidence
Breath alignment, the back rayleigh scattering optical signal that can obtain each point changes with time (time interval of change is nT), will
The signal that each position is changed over time carries out Fourier transformation processing, and seeks power spectrum, can obtain what is each put on optical fiber
The frequency spectrum of back rayleigh scattering optical signal.Apply vibration in the diverse location of two sections of sensor fibres of multiplexing respectively, can obtain
Frequency spectrum is as shown in Figure 6.The vibration that 10Hz is with the addition of at the first via sensor fibre beginning of multiplexing can be analyzed from frequency spectrum, it is multiple
15Hz and 10Hz vibration are with the addition of at second road optical fiber beginning and at 540m respectively.Transducing signal is not between the two-way of multiplexing
Interfere, sensing outcome can be respectively obtained, and the disturbance of connection optical fiber does not interfere with disturbance measurement, it is jamproof with height
Ability.
Direct impulse is first divided into two energy by the present invention by introducing a polarization beam apparatus and a polarization beam combiner
Equal orthogonal polarization components, then be synthesized together after a small amount of delay, the direct impulse light of synthesis is through circulator by connecting
Enter analyzer after optical fiber transmission.Analyzer is arranged on the front end of sensor fibre.No matter which kind of connection optical fiber disturbed by, pass through
The energy and polarization state that analyzer enters the direct impulse of sensor fibre keep constant, it is ensured that to polarization signal in sensor fibre
The stability of measurement.Direct impulse will be visited by entering back into optical fiber, the scattered light of optical fiber after analyzer by circulator into snowslide
Survey device and the polarization signal along optical fiber is sensed by signal analysis.By the connection for introducing coupler and different length
Optical fiber, the POTDR systems are measured while can realizing to being disturbed in multi-channel optical fibre, and each road signal is not interfere with each other.The present invention can
To eliminate POTDR systems with connecting influence of the unrelated disturbance to sensing detection on optical fiber between sensor fibre, with anti-interference energy
The characteristics of power is strong；By multiplexing, the system can detect the disturbance in multiple separate regions simultaneously.
Above content is to combine specific preferred embodiment further description made for the present invention, it is impossible to assert
The specific implementation of the present invention is confined to these explanations.For general technical staff of the technical field of the invention,
On the premise of not departing from present inventive concept, some simple deductions or replacement can also be made, should all be considered as belonging to the present invention's
Protection domain.
Claims (10)
1. a kind of system of the survey disturbance based on POTDR, it is characterised in that including laser module, Polarization Controller, polarization beam splitting
Device, polarization maintaining optical fibre, polarization beam combiner, circulator, connection optical fiber, analyzer, avalanche photodetector, capture card and processor；
Wherein,
Laser module, for the pulsed light of the complete polarization of output to be exported to polarization beam apparatus through Polarization Controller；
Polarization beam apparatus, for the control through Polarization Controller, the output pulse that two-way polarization state is mutually orthogonal and power is equal
Light；Wherein, all the way pulse light output to polarization beam combiner；Another road pulsed light is exported to polarization beam combiner through polarization maintaining optical fibre；
Polarization beam combiner, for the two-way received pulsed light to be synthesized, the pulsed light after synthesis is through circulator, connection light
Exported after fine, analyzer to outside sensor fibre, the pulsed light exported by analyzer transmits the back of the body of generation in sensor fibre
To Rayleigh scattering light reversely again by being exported after analyzer through circulator to avalanche photodetector；
Avalanche photodetector, is exported to capture card for the back rayleigh scattering received light to be converted to after electric signal；
Capture card, for the electric signal output of collection to processor to be analyzed and processed, so as to obtain along sensor fibre
Destabilization sensing information.
2. a kind of system of survey disturbance based on POTDR according to claim 1, it is characterised in that the laser module
Including pulse laser and the polarizer；Wherein,
Pulse laser, for output optical pulse to the polarizer；
The polarizer, for ensureing that pulsed light is exported to polarization by thereafter, exporting the pulsed light polarized completely through Polarization Controller
Beam splitter.
3. the method based on a kind of survey perturbed system based on POTDR described in claim 1, it is characterised in that including following
Step：
Step (1), to sensor fibre injected pulse light at the same time, processor persistently receives multigroup dorsad Rayleigh and dissipated
Optical signal is penetrated, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step (2), to obtained in step (1) it is average after back rayleigh scattering optical signal, it is poor using adjacent signals are carried out
The mode divided realizes the positioning to disturbance point；
Step (3), by obtained in step (1) it is average after back rayleigh scattering optical signal, using the method pair of spectrum analysis
The frequency of disturbing signal and position are measured.
4. a kind of system of the survey disturbance based on POTDR, it is characterised in that including laser module, Polarization Controller, polarization beam splitting
Device, polarization maintaining optical fibre, polarization beam combiner, circulator, 1 × N couplers, multiple connection optical fiber, multiple analyzers, avalanche optoelectronic detection
Device, capture card and processor；One end of connection optical fiber is connected one by one respectively with the output end of 1 × N couplers, connects the another of optical fiber
One end is connected one by one respectively with analyzer, and the number of connection optical fiber and analyzer is N, and N is the integer more than 1, connects optical fiber
Length it is different；Wherein,
Laser module, for the pulsed light of the complete polarization of output to be exported to polarization beam apparatus through Polarization Controller；
Polarization beam apparatus, for the control through Polarization Controller, the output pulse that two-way polarization state is mutually orthogonal and power is equal
Light；Wherein, all the way pulse light output to polarization beam combiner；Another road pulsed light is exported to polarization beam combiner through polarization maintaining optical fibre；
Polarization beam combiner, for the two-way received pulsed light to be synthesized, the pulsed light after synthesis is through circulator, 1 × N couplings
After clutch, output N roads light is exported after distinguishing the connection optical fiber being connected respectively through the output end with 1 × N couplers successively, analyzer
To outside multiple sensor fibres, the pulsed light exported by analyzer transmits the back rayleigh scattering light of generation in sensor fibre
Reversely again by being exported after analyzer through circulator to avalanche photodetector；The dorsad Rayleigh that each sensor fibre is produced dissipates
Light is penetrated in time domain to stagger；
Avalanche photodetector, is exported to capture card for back rayleigh scattering light to be converted to after electric signal；
Capture card, for the electric signal output of collection to processor to be analyzed and processed, so as to realize to multiple sensor fibres
Measured while destabilization sensing information along the line.
5. a kind of system of survey disturbance based on POTDR according to claim 4, it is characterised in that the laser module
Including pulse laser and the polarizer；Wherein,
Pulse laser, for output optical pulse to the polarizer；
The polarizer, for ensureing that pulsed light is exported to polarization by thereafter, exporting the pulsed light polarized completely through Polarization Controller
Beam splitter.
6. a kind of system of survey disturbance based on POTDR according to claim 4, it is characterised in that the letter on each road of multiplexing
Number stagger in time domain, do not interfere with each other mutually, be more than or equal to per the length of connection optical fiber all the way previous in multiplexing structure
The connection optical fiber and sensor fibre length sum on road.
7. the method based on a kind of survey perturbed system based on POTDR described in claim 4, it is characterised in that including following
Step：
Step (1), to sensor fibre injected pulse light at the same time, processor persistently receives multigroup dorsad Rayleigh and dissipated
Optical signal is penetrated, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step (2), to obtained in step (1) it is average after back rayleigh scattering optical signal, difference is carried out to adjacent signals
Mode realizes the positioning to disturbance point；
Step (3), by obtained in step (1) it is average after back rayleigh scattering optical signal, using the method pair of spectrum analysis
The frequency of disturbing signal and position are measured.
8. a kind of survey perturbation motion method based on POTDR, it is characterised in that comprise the following steps：
Step 1: the pulsed light that two-way polarization state is mutually orthogonal and power is equal is synthesized；
Step 2: the pulsed light after synthesis is exported to outside sensor fibre, by examining after circulator, connection optical fiber, analyzer
The pulsed light of inclined device output transmitted in sensor fibre the back rayleigh scattering light of generation reversely again by after analyzer through ring
Shape device is exported to receiving terminal；
Step 3: to sensor fibre injected pulse light at the same time, receiving terminal persistently receives multigroup dorsad Rayleigh and dissipated
Optical signal is penetrated, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step 4: to obtained in step 3 it is average after back rayleigh scattering optical signal, adjacent signals are carried out with the side of difference
Formula realizes the positioning to disturbance point；
Step 5: by obtained in step 3 it is average after back rayleigh scattering optical signal, using the method for spectrum analysis to disturbing
The frequency of dynamic signal and position are measured.
9. a kind of survey perturbation motion method based on POTDR, it is characterised in that comprise the following steps：
Step 1: the pulsed light that two-way polarization state is mutually orthogonal and power is equal is synthesized；
Step 2: the pulsed light after synthesis is after circulator, 1 × N couplers, output N roads light with 1 × N respectively successively through coupling
The connection optical fiber of the output end connection of device, export to multiple sensor fibres of outside after analyzer, the pulse exported by analyzer
Light transmits the back rayleigh scattering light of generation reversely again by being exported after analyzer through circulator to reception in sensor fibre
End；The number for connecting optical fiber and analyzer is N, and the one end and the output end of 1 × N couplers for connecting optical fiber connect one by one respectively
Connect, the other end of connection optical fiber is connected one by one respectively with analyzer, N is the integer more than 1, the length for connecting optical fiber is different,
The back rayleigh scattering light that each sensor fibre is produced staggers in time domain；
Step 3: to sensor fibre injected pulse light at the same time, receiving terminal persistently receives multigroup dorsad Rayleigh and dissipated
Optical signal is penetrated, takes continuous multigroup back rayleigh scattering optical signal to do cumulative mean；
Step 4: to obtained in step 3 it is average after back rayleigh scattering optical signal, adjacent signals are carried out with the side of difference
Formula realizes the positioning to disturbance point；
Step 5: by obtained in step 3 it is average after back rayleigh scattering optical signal, using the method for spectrum analysis to disturbing
The frequency of dynamic signal and position are measured.
10. a kind of survey perturbation motion method based on POTDR according to claim 9, it is characterised in that the signal on each road of multiplexing
Stagger in time domain, do not interfere with each other mutually, before being more than or equal to per the length of connection optical fiber all the way in multiplexing structure all the way
Connection optical fiber and sensor fibre length sum.
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| CN112284690A (en) * | 2020-10-28 | 2021-01-29 | 山东省科学院激光研究所 | Testing device for accurately measuring distribution of distributed radial refractive indexes of optical fibers |
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