CN207894512U - Vibration sensor based on φ-OTDR - Google Patents
Vibration sensor based on φ-OTDR Download PDFInfo
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- CN207894512U CN207894512U CN201721920937.6U CN201721920937U CN207894512U CN 207894512 U CN207894512 U CN 207894512U CN 201721920937 U CN201721920937 U CN 201721920937U CN 207894512 U CN207894512 U CN 207894512U
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Abstract
The utility model discloses a kind of vibration sensors based on φ OTDR, including computer, super-narrow line width laser, waveform generator, acousto-optic modulator, AOM drivers, erbium-doped fiber amplifier, circulator, sensor fibre, the first coupler, the second coupler, balanced detector and capture card.For the utility model while ensuring measurement accuracy, the requirement to component is few, high sensitivity and at low cost, can be used for the distributed fiberoptic sensor of high position precision.
Description
Technical field
The utility model is related to Distributed Optical Fiber Sensing Techniques fields, and the measurement for being specifically namely based on φ-OTDR is shaken
The distributed optical fiber vibration sensing device of dynamic signal.
Background technology
Vibration sensor based on φ-OTDR is mainly used for the places such as building, industrial park, underground utilities, to these
Important place carries out comprehensive vibration monitoring in real time, is a kind of optical fiber sensing technology using optical fiber as sensing medium.One
Under fixed condition, optical fiber is particularly easy to receive to be a kind of excellent sensitivity by the influence of the factors such as the vibration in place and ambient temperature
Element.Simultaneously optical fiber electrical isolation itself, small, electromagnetism interference, it is corrosion-resistant, particularly suitable for inflammable and explosive, narrow space
Or it is used under the place of strong electromagnetic.Therefore, optical fiber sensing technology just has been attached great importance once appearance, becomes sensing
The guide of technology pushes flourishing for sensing technology.
Common vibrating sensor is by there is five kinds of magnetoelectricity type, Eddy Current Type, piezo-electric type, capacitive, inductive type etc. at present.This
A little sensors belong to electronics this block, installation and the intricate operation being laid with, and are easily damaged.Due to using conducting wire as transmission
Medium, detecting distance can not be accomplished far, and simultaneity factor can obtain and data itself limitation handled is very big.Its peace simultaneously
Dress mode and conducting wire paving mode also have large effect to measurement result, this problem will cause very for field calibration
Mostly unnecessary workload.Both are vulnerable to the interference of surrounding medium for capacitive and inductive type, influence its working condition, at present
It seldom uses.Also occurs the vibration sensor based on fiber grating sensing technology currently on the market, transmission medium is light
Fine grating perceives the variation of extraneous physical parameter by perceiving the drift of grating wavelength itself.But the raising of its resolution ratio is complete
Wideband light source is depended on entirely, while must also use high performance monochromator or spectrometer to improve sensitivity, so,
The cost of whole equipment is absolutely not low, while its detection range is also limited, can not be improved simply by improving light source power.Just
The even grating of its detection, cost is not also low, and the tie point between each grating is also susceptible to problem.
Utility model content
The purpose of this utility model is to provide a kind of suitable distributing optical fiber sensing of simple in structure while monitoring sensitivity
Device.The device is under the premise of ensureing Signal-to-Noise and detection range, a large amount of simplied system structures, reduces hardware cost,
The volume of this block of light path is reduced, while data are pre-processed with envelope detector, reduces the pressure of subsequent software, is improved whole
The response speed of a system.
A kind of vibration sensor based on φ-OTDR is provided, which includes computer, waveform generator, AOM drivings
Device, acousto-optic modulator, erbium-doped fiber amplifier, circulator, sensor fibre, laser, clock-pulse generator, the first coupling
Device, the second coupler, balanced detector, capture card and envelope detector.
The computer is connected by serial ports with clock-pulse generator, and the clock-pulse generator is sent out with waveform respectively
Raw device is connected with capture card, while the synchronised clock of clock-pulse generator being sent on capture card；The waveform generator
Output end connect with the input terminal of the AOM drivers, the output ends of the AOM drivers connects with the acousto-optic modulator
It connects；
The output end of the laser is connected with the input terminal of the first coupler, and the continuous light of generation passes through first coupling
Clutch is divided into the continuous light of two beams；One output end of first coupler is connected with the input terminal of the acousto-optic modulator, institute
It states acousto-optic modulator output end to be directly connected with the input terminal of the erbium-doped fiber amplifier, the light of the erbium-doped fiber amplifier
No. 1 port of source output terminal and circulator connects, and No. 2 ports of circulator are connect with the sensor fibre；First coupler
Another output end is connected with a port of the second coupler, and No. 3 ports and another port of the second coupler of circulator connect
It connects；
Two output ends of the second coupler are connect with two input terminals of balanced detector respectively；Balanced detector exports
End is connect with the envelope detector, and the output end of the capture card is connect with the computer.
Above-mentioned technical proposal is connect, the computer is connected by 232 serial ports with clock-pulse generator.
Above-mentioned technical proposal is connect, the computer is connected by pci interface with capture card.
Above-mentioned technical proposal is connect, first coupler is 94：6 couplers, energy account for 94% output end with it is described
The input terminal of acousto-optic modulator is connected, and the output end that energy accounts for 94% is connect with a port of the second coupler.
Above-mentioned technical proposal is connect, second coupler is 50：50 couplers.
Above-mentioned technical proposal is connect, the laser is narrow linewidth laser.
Above-mentioned technical proposal is connect, the AOM drivers are acousto-optic driver.
Compared with prior art, the utility model has numerous advantages.The present apparatus using ordinary optic fibre as transmission medium, with
Common communications optical cable is equally laid with conveniently, installs and influence of the mode of laying to measurement result is smaller, and optical cable itself is no
It is fragile.The present apparatus utilizes the design of intrinsic light and EDFA dual amplifications simultaneously, that is, extends detection range, and ensure signal
Quality.Since the present apparatus is based on the Rayleigh scattering principle in optical fiber so that whole optical fiber is all sensor, and spatial resolution is no longer
It is limited by light source.Only it need to can reach requirement of the actual environment to resolution ratio by the adjustment of sample frequency and pulse width.
Then the mode for using this kind of hardware demodulation of envelope detector directly handles data, that is, reduces the solution pressure regulation of subsequent software level
Power, and ensure the speed of service of whole system, so that subsequent software is handled in real time and detects caused mass data over long distances.
Fibre optical sensor cost is excessively high in the prior art for present apparatus solution, signal processing excessive cycle, not remote enough the problem of monitoring distance.
Description of the drawings
Fig. 1 is the system construction drawing of the vibration sensor based on φ-OTDR.
Specific implementation mode
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
Example, the present invention will be further described in detail.It should be appreciated that specific embodiment described herein is only explaining this
Utility model is not used to limit the utility model.
Fig. 1 is the system construction drawing of the utility model, including device：Computer, waveform generator, AOM drivers, acousto-optic
Modulator (AOM), erbium-doped fiber amplifier (EDFA), circulator, sensor fibre, laser (LD), clock-pulse generator,
One coupler (can be selected 94:6 couplers), the second coupler (can be selected 50:50 couplers), balanced detector, capture card
(DAQ), envelope detector.
Computer is connected by 232 serial ports with clock-pulse generator, then clock-pulse generator respectively with waveform
Generator is connected with capture card, is synchronous with the trigger pulse ensured between AOM and capture card, while lock-out pulse being occurred
The synchronised clock of device is sent on capture card, and the internal clocking to ensure capture card internal clocking and clock-pulse generator is same
Step, the frequency of synchronised clock are set as the sine wave of fixed frequency.
The output end of laser and 94:The input terminal of 6 couplers is connected, and the continuous light of generation passes through 94:6 coupler point
At the continuous light of two beams.Energy Zhan94%Na road light is connected with the input terminal of AOM, the output end of AOM directly with the input of EDFA
End is connected, and is connected with No. 1 port of circulator by the EDFA optical signals amplified, the light source output end of EDFA and the 1 of circulator
The connection of number port, No. 2 ports of circulator are connect with sensor fibre；Energy accounts for No. 2 of 6% that end directly with three-dB coupler
Port is connected, and No. 3 ports of circulator are connect with No. 1 port of the second coupler (optional three-dB coupler).Three-dB coupler
Two output ends connect respectively with two input terminals of balanced detector.The electric signal of balanced detector output, by envelope
The processing of wave detector, and converted by certain coefficient, directly by continuous signal transfer to capture card, data acquisition is carried out,
Collected data are sent directly into computer and make subsequent analysis.
The computer is connected by pci interface with capture card, realizes the initialization of capture card and will be after preliminary treatment
Data are directed into subsequent software module, complete the analyzing processing of related data, the final intelligent recognition for realizing computer and control
Operation.
In the utility model, AOM introduces the light that continuous light is cut into fixed frequency and pulsewidth by a fixed frequency simultaneously；For
The frequency information of carrier wave can be collected by ensureing DAQ, and sample frequency is more preferably greater than 3 to 4 times of frequency shifts, such as AOM institutes
The fixed frequency of introducing is 80MHz, then the sample frequency of capture card is preferably not less than 250MHz, at the same capture card using it is external when
Clock is as synchronous clock source；Laser herein selects narrow linewidth laser, and centre frequency 1550nm, line width is in several kHz
Near, output power be more than ten mw just；The rising time of AOM and failing edge time are small as far as possible, and operation wavelength exists
Between 1530nm to 1565nm, while included acousto-optic driver is selected as possible；Circulator requires it to be operated in C-band, isolation
Degree is more than 45dB, bears power and is less than 500mw；The operation wavelength of EDFA is 1530nm to 1560nm, noise coefficient 5.5dB.
The centre wavelength of balanced detector is 1550nm, bandwidth 80MHz, and it is 30dB to receive sensitivity.
AOM can introduce a fixed frequency shifts within the system, and after balanced detector, which will be at
For the carrier frequency of electric signal, and follow-up required signal is exactly the envelope signal in electric signal.By the place of envelope detector
Reason, and converted by certain coefficient, directly by continuous signal transfer to capture card, carry out data acquisition, collected number
According to being sent directly into data source of the computer as subsequent processing.
In the utility model, computer sends a control AOM frequency and arteries and veins by RS232 interface, to waveform generator
After wide order, continuous light is converted to the pulsed light of corresponding pulsewidth and repetition rate by AOM, while introducing a fixed frequency
It is mobile.Pulsed light is generated in sensor fibre by the rear to Rayleigh scattering light of external world's modulation, is mixed by 90 ° of frequency mixers, then
Electric signal is converted to by balanced detector.For the utility model while ensuring measurement accuracy, the requirement to component is few, spirit
Sensitivity is high and at low cost, can be used for the distributed fiberoptic sensor of high position precision.
It should be understood that for those of ordinary skills, it can be modified or changed according to the above description,
And all these modifications and variations should all belong to the protection domain of the appended claims for the utility model.
Claims (7)
1. a kind of vibration sensor based on φ-OTDR, which is characterized in that the device include computer, waveform generator,
AOM drivers, acousto-optic modulator, erbium-doped fiber amplifier, circulator, sensor fibre, laser, clock-pulse generator,
One coupler, the second coupler, balanced detector, capture card and envelope detector；
The computer is connected by serial ports with clock-pulse generator, the clock-pulse generator respectively with waveform generator
It is connected with capture card, while the synchronised clock of clock-pulse generator is sent on capture card；The waveform generator it is defeated
Outlet is connect with the input terminal of the AOM drivers, and the output end of the AOM drivers is connect with the acousto-optic modulator；
The output end of the laser is connected with the input terminal of the first coupler, and the continuous light of generation passes through first coupler
It is divided into the continuous light of two beams；One output end of first coupler is connected with the input terminal of the acousto-optic modulator, the sound
Optical modulator output end is directly connected with the input terminal of the erbium-doped fiber amplifier, and the light source of the erbium-doped fiber amplifier is defeated
No. 1 port of outlet and circulator connects, and No. 2 ports of circulator are connect with the sensor fibre；First coupler it is another
Output end is connected with a port of the second coupler, and No. 3 ports of circulator are connect another port with the second coupler；
Two output ends of the second coupler are connect with two input terminals of balanced detector respectively；Balanced detector output end with
The envelope detector connection, the output end of the capture card are connect with the computer.
2. the vibration sensor according to claim 1 based on φ-OTDR, which is characterized in that the computer passes through
232 serial ports are connected with clock-pulse generator.
3. the vibration sensor according to claim 1 based on φ-OTDR, which is characterized in that the computer passes through
Pci interface is connected with capture card.
4. the vibration sensor according to claim 1 based on φ-OTDR, which is characterized in that first coupler
It is 94：6 couplers, the output end that energy accounts for 94% are connected with the input terminal of the acousto-optic modulator, energy account for 94% it is defeated
Outlet is connect with a port of the second coupler.
5. the vibration sensor according to claim 1 based on φ-OTDR, which is characterized in that second coupler
It is 50：50 couplers.
6. the vibration sensor according to claim 1 based on φ-OTDR, which is characterized in that the laser is narrow
Line width laser.
7. the vibration sensor according to claim 1 based on φ-OTDR, which is characterized in that the AOM drivers are
Acousto-optic driver.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201721920937.6U CN207894512U (en) | 2017-12-30 | 2017-12-30 | Vibration sensor based on φ-OTDR |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721920937.6U CN207894512U (en) | 2017-12-30 | 2017-12-30 | Vibration sensor based on φ-OTDR |
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| CN207894512U true CN207894512U (en) | 2018-09-21 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109374115A (en) * | 2018-12-07 | 2019-02-22 | 武汉理工光科股份有限公司 | Broken vibration monitoring recognition methods outside oil-gas pipeline based on φ-OTDR |
| CN109828631A (en) * | 2019-01-23 | 2019-05-31 | 中国科学技术大学 | Random waveform generating system |
| CN111147133A (en) * | 2019-12-24 | 2020-05-12 | 武汉理工光科股份有限公司 | Real-time monitoring system and method for traffic flow based on phi-OTDR |
| CN111192424A (en) * | 2020-01-09 | 2020-05-22 | 国网山西省电力公司太原供电公司 | Optical cable intrusion monitoring system and method based on optical fiber sensing technology |
| CN111609918A (en) * | 2020-06-09 | 2020-09-01 | 重庆大学 | Optical fiber distributed vibration sensing system based on envelope detection circuit |
-
2017
- 2017-12-30 CN CN201721920937.6U patent/CN207894512U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109374115A (en) * | 2018-12-07 | 2019-02-22 | 武汉理工光科股份有限公司 | Broken vibration monitoring recognition methods outside oil-gas pipeline based on φ-OTDR |
| CN109828631A (en) * | 2019-01-23 | 2019-05-31 | 中国科学技术大学 | Random waveform generating system |
| CN111147133A (en) * | 2019-12-24 | 2020-05-12 | 武汉理工光科股份有限公司 | Real-time monitoring system and method for traffic flow based on phi-OTDR |
| CN111192424A (en) * | 2020-01-09 | 2020-05-22 | 国网山西省电力公司太原供电公司 | Optical cable intrusion monitoring system and method based on optical fiber sensing technology |
| CN111609918A (en) * | 2020-06-09 | 2020-09-01 | 重庆大学 | Optical fiber distributed vibration sensing system based on envelope detection circuit |
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