CN209264103U - A kind of distributed optical fiber vibration sensing system demodulating equipment - Google Patents
A kind of distributed optical fiber vibration sensing system demodulating equipment Download PDFInfo
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- CN209264103U CN209264103U CN201822086261.6U CN201822086261U CN209264103U CN 209264103 U CN209264103 U CN 209264103U CN 201822086261 U CN201822086261 U CN 201822086261U CN 209264103 U CN209264103 U CN 209264103U
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Abstract
The utility model discloses a kind of distributed optical fiber vibration sensing system demodulating equipments, it include: light source module, light source module is divided into two-way after connecting with coupler, wherein connecting by the first optical fiber with circulator after being sequentially connected in series acousto-optic modulator and the first fiber amplifier all the way；Another way is sequentially connected in series after electrooptic modulator and the second fiber amplifier and connect by the second optical fiber with circulator；The circulator connects sensor fibre；The output of the circulator is sequentially connected in series photoelectric conversion module, high-pass filter, data acquisition module and host computer.After there is interference signal, detector can be quickly obtained the information such as position and the disturbing signal intensity of disturbing signal, solve the problems, such as that Φ-OTDR Demodulation Systems algorithm is complicated and laser frequency is drifted about, ensure that the position error of system within ± 1m.
Description
Technical field
The utility model relates to technical field of optical fiber sensing, in particular to a kind of distributed optical fiber vibration sensing system demodulation
Device.
Background technique
Distributed optical fiber vibration sensing system may be implemented long range, distributed destabilization sensing and signal and transmit, and pass through inspection
The light intensity variation for surveying optical fiber each section back scattering interference light, realizes and invades and harasses movable detection to outside, in conjunction with optical time domain reflection
Technology can realize the accurate positionin of vibration signal.Distributed optical fiber vibration sensing system is using optical fiber itself as sensor and letter
Number transmission carrier, have many advantages, such as measurement accuracy height, fast response time, intrinsic safety, can be in inflammable, explosive, high temperature, height
Long-term stable operation in the rugged environments such as wet, high corrosion and strong-electromagnetic field interference is supervised safely in circumference security protection, petroleum pipeline
The fields such as survey, rail traffic, building structure health have a wide range of applications.
With the continuous expansion of application field, distributed optical fiber vibration sensing system can be divided into phase sensitive from principle
Optical time domain reflection technology (Ф-OTDR), polarized light time domain reflection technology (P-OTDR), coherent light time domain reflection technology (C-OTDR)
Deng.Wherein, for Ф-OTDR by high sensitivity, the advantage of measurement distance, application is more and more extensive.Ф-OTDR is usually using biography
The Rayleigh scattering light of photosensitive fibre and the local oscillator light of light source obtain interference optical field, then are shaken by the phase demodulating to interference optical field
Dynamic signal.Demodulation accuracy is easy to be influenced by the polarization state variation of light source with frequency stability.Demodulating process includes mixing, filter
The operations such as wave and difference, complexity is high, and response speed is slow.
Utility model content
To solve the above-mentioned problems, the utility model proposes a kind of distributed optical fiber vibration sensing system demodulating equipment,
The influence for eliminating the polarization state variation and frequency stability of light source, improves demodulation accuracy；Demodulation structure is simplified, it can be quick
The amplitude-frequency information vibrated reduces the demodulation response time.
To achieve the goals above, the utility model adopts the following technical solution:
A kind of distributed optical fiber vibration sensing system demodulating equipment disclosed in one or more embodiments, comprising:
Light source module, light source module are divided into two-way after connecting with coupler, wherein being sequentially connected in series acousto-optic modulator and the first optical fiber all the way
It is connect by the first optical fiber with circulator after amplifier；Another way passes through after being sequentially connected in series electrooptic modulator and the second fiber amplifier
The second optical fiber is crossed to connect with circulator；The circulator connects sensor fibre；The output of the circulator is sequentially connected in series light
Electric conversion module, high-pass filter, data acquisition module and host computer.
Further, the length of first optical fiber and the second optical fiber is different, the length of first optical fiber and the second optical fiber
Degree difference is determined by the transmission speed of modulated signal pulsewidth and light in a fiber, and the transmission time of two-way optical path is finally made to differ setting
Pulse period.
Further, the length of first optical fiber and the second optical fiber is identical, using double-pulse signal generator driving sound
Optical modulator and electrooptic modulator are modulated light pulse respectively, the modulation pulsewidth of modulation intervals difference setting.
Further, it is the coupler of 50:50 that the coupler, which selects splitting ratio,.
Further, the light source module includes: laser light source interconnected and narrow linewidth continuous laser driver.
Compared with prior art, the utility model has the beneficial effects that
(1) using the interference optical field formed after the two-way in sensor fibre to Rayleigh scattering optical superposition, demodulation is vibrated
Signal eliminates the influence of the polarization state variation and frequency stability of light source, improves demodulation accuracy.
(2) optical path difference determining by setting, the phase difference of interference light intensity directly reflect the amplitude-frequency information of vibration signal, keep away
The processes such as mixing, filtering and difference operation are exempted from, have simplified demodulation method, reduce the response time.
(3) can according to determining optical path difference, adjust pulse width, guarantee two-way pulsed light differ a pulse width into
Enter sensor fibre, flexibility ratio is high, Yi Shixian.
(4) after there is interference signal, detector can be quickly obtained position and the disturbing signal intensity of disturbing signal
Etc. information, solve the problems, such as that Φ-OTDR Demodulation Systems algorithms is complicated and laser frequency is drifted about, ensure that the positioning of system misses
Difference is within ± 1m.
Detailed description of the invention
The accompanying drawings constituting a part of this application is used to provide further understanding of the present application, and the application's shows
Meaning property embodiment and its explanation are not constituted an undue limitation on the present application for explaining the application.
Fig. 1 is distributed optical fiber vibration sensing system demodulating equipment structural schematic diagram in embodiment two；
Fig. 2 is distributed optical fiber vibration sensing system demodulating equipment structural schematic diagram in embodiment three；
Wherein, 1- light source module, 2- coupler, 3- signal generator, 4- driver, 5- acousto-optic modulator, 6- first mix
Doped fiber amplifier, 7- electrooptic modulator, the second erbium-doped fiber amplifier of 8-, the second optical fiber of 9-, 10- circulator, 11- sense light
Fibre, 12- photoelectric conversion module, 13- high-pass filter, 14- data acquisition module, 15- host computer, 16- dipulse signal occur
Device.
Specific embodiment
It is noted that following detailed description is all illustrative, it is intended to provide further instruction to the application.Unless another
It indicates, all technical and scientific terms that the utility model uses have the ordinary skill people with the application technical field
The normally understood identical meanings of member.
It should be noted that term used herein above is merely to describe specific embodiment, and be not intended to restricted root
According to the illustrative embodiments of the application.As used herein, unless the context clearly indicates otherwise, otherwise singular
Also it is intended to include plural form, additionally, it should be understood that, when in the present specification using term "comprising" and/or " packet
Include " when, indicate existing characteristics, step, operation, device, component and/or their combination.
Embodiment one
A kind of distributed optical fiber vibration sensing system demodulating equipment, such as Fig. 1 are disclosed in one or more embodiments
It is shown, comprising: light source module 1 is connect with coupler 2, and the output of coupler 2 is divided into two-way, wherein being sequentially connected in series sound all the way
After optical modulator 5, the first erbium-doped fiber amplifier 6 (EDFA), it is connect by the first optical fiber with circulator 10；Another way is successively gone here and there
After connection connection electrooptic modulator 7, the second erbium-doped fiber amplifier 8 (EDFA), it is connect by the second optical fiber 9 with circulator 10；Ring
Shape device 10 connects sensor fibre 11；Meanwhile circulator 10 is sequentially connected in series photoelectric conversion module 12, high-pass filter 13, number
According to acquisition module 14 and host computer 15.
The distance of difference setting length between first optical fiber and the second optical fiber 9.
Light source module 1 includes laser light source, narrow linewidth continuous laser driver 4, and light source module 1 generates super-narrow line width laser
It is divided into two bundles the identical continuous light of optical power by coupler 2, is separately connected acousto-optic modulator 5 (AOM) and electrooptic modulator 7
(EOM)；
Signal generator 3 connects drive module, and drive module drives acousto-optic modulator 5 and electrooptic modulator 7 to continuous light
It is modulated；Modulated two-way pulsed optical signals are separately connected erbium-doped fiber amplifier and carry out power amplification, and are transferred through
The constant optical fiber link of length difference enters sensor fibre 11 using circulator 10；The backward Rayleigh scattering light of sensor fibre 11
Enter photoelectric conversion module 12 (PD) by circulator 10；Photoelectric conversion module 12 converts optical signals into electric signal, is output to
High-pass filter 13 (HPF)；High-pass filter 13 is output to data acquisition module 14 after filtering to electric signal；Data acquisition module
Analog electrical signal is converted to digital signal and gives host computer 15 by 14 (DAQ)；Host computer 15 is obtained according to obtained digital signal
The vibration information that sensor fibre 11 perceives.
Firstly, the ultra-narrow pulse width laser that light source module 1 generates is divided into two bundles by coupler 2 and respectively enters acousto-optic modulator
5 and electrooptic modulator 7, light source center wavelength 1550nm, fcFor light source frequency；Drive module drives acousto-optic modulator 5 and electric light
Modulator 7 is modulated light pulse respectively, modulating frequency f0=80MHz, modulation pulsewidth are Δ t=100ns；Two-way modulation
Optical signal afterwards passes through the first erbium-doped fiber amplifier 6 respectively, the second erbium-doped fiber amplifier 8 amplifies；Optical fibre refractivity
For nOptical fiber=1.5, the spread speed of light in a vacuum is cVacuum=3 × 108M/s, then light spread speed in a fiber are as follows:
The distance L=Δ t × c differed before first optical fiber and the second lightOptical fiber=100ns × 2 × 108M/s=20m.Pass through
Enter circulator 10 after the optical fiber of two-way length difference 20m, two-way light differs Δ tc=100ns, exactly pulse period；
Photoelectric conversion module 12 converts optical signals into electric signal, shown in phase relation such as formula (5) caused by electric current and vibration signal；
The rayleigh backscattering light that sensor fibre 11 generates inputs high-pass filter 13 by circulator 10 and is filtered, and filters out DC quantity
Leave behind of ac；
Digital signal is converted to through the data collecting card that over-sampling rate is 400MHz, and is transmitted to the progress of host computer 15
Demodulating algorithm operation is denoised, treatment process is simplified, it is fixed to improve the demodulation of distributed optical fiber vibration sensing system vibration signal waveforms
Position efficiency.
The time difference of two pulsed optical signals input is fixed；The frequency difference of two pulsed optical signals is also fixed
's；The width of two pulse signals is identical；The signal for being loaded into acousto-optic modulator 5 is input in sensor fibre 11, initial phase
Position is fixed.When effect of vibration is in sensor fibre 11, the variation of phase is directly displayed at interference of light letter in sensor fibre 11
Number waveform on, can by calculate demodulate phase value, directly obtain waveform and the position of vibration.
Embodiment two
A kind of distributed optical fiber vibration sensing system demodulating equipment disclosed in present embodiment, as shown in Fig. 2, and embodiment
Unlike device in two, in present embodiment, the first optical fiber is identical as the conveying length of the second optical fiber 9, using dipulse
Signal generator 16 drives acousto-optic modulator 5 and electrooptic modulator 7 to be modulated light pulse respectively, and modulation intervals differ one
Modulation pulsewidth enters two-way optical path, substitutes two-way optical fiber optical path difference, reduces the influence of environmental factor.
Remaining structure and the course of work are identical with embodiment two, repeat no more.
It is above-mentioned although specific embodiments of the present invention are described with reference to the accompanying drawings, but it is not practical new to this
The limitation of type protection scope, those skilled in the art should understand that, based on the technical solution of the present invention, ability
Field technique personnel do not need to make the creative labor the various modifications or changes that can be made still in the protection model of the utility model
Within enclosing.
Claims (5)
1. a kind of distributed optical fiber vibration sensing system demodulating equipment characterized by comprising light source module, light source module with
It is divided into two-way after coupler connection, wherein being sequentially connected in series after acousto-optic modulator and the first fiber amplifier all the way by the first optical fiber
It is connect with circulator；Another way connects after being sequentially connected in series electrooptic modulator and the second fiber amplifier by the second optical fiber and circulator
It connects；The circulator connects sensor fibre；The output of the circulator is sequentially connected in series photoelectric conversion module, high-pass filtering
Device, data acquisition module and host computer.
2. a kind of distributed optical fiber vibration sensing system demodulating equipment as described in claim 1, which is characterized in that described first
The length of optical fiber and the second optical fiber is different, and the length difference of first optical fiber and the second optical fiber is by modulated signal pulsewidth and light in light
Transmission speed in fibre determines, the transmission time of two-way optical path is finally made to differ the pulse period of setting.
3. a kind of distributed optical fiber vibration sensing system demodulating equipment as described in claim 1, which is characterized in that described first
The length of optical fiber and the second optical fiber is identical, drives acousto-optic modulator and electrooptic modulator to light arteries and veins using double-pulse signal generator
Punching is modulated respectively, the modulation pulsewidth of modulation intervals difference setting.
4. a kind of distributed optical fiber vibration sensing system demodulating equipment as described in claim 1, which is characterized in that the coupling
It is the coupler of 50:50 that device, which selects splitting ratio,.
5. a kind of distributed optical fiber vibration sensing system demodulating equipment as described in claim 1, which is characterized in that the light source
Module includes: laser light source interconnected and narrow linewidth continuous laser driver.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109405956A (en) * | 2018-12-11 | 2019-03-01 | 珠海任驰光电科技有限公司 | A kind of distributed optical fiber vibration sensing system demodulation method and device |
| CN111323144A (en) * | 2020-03-27 | 2020-06-23 | 武汉理工大学 | Distributed optical fiber sensing system for simultaneously measuring temperature, strain and vibration |
-
2018
- 2018-12-11 CN CN201822086261.6U patent/CN209264103U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109405956A (en) * | 2018-12-11 | 2019-03-01 | 珠海任驰光电科技有限公司 | A kind of distributed optical fiber vibration sensing system demodulation method and device |
| CN111323144A (en) * | 2020-03-27 | 2020-06-23 | 武汉理工大学 | Distributed optical fiber sensing system for simultaneously measuring temperature, strain and vibration |
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