CN106949954B - A kind of fiber-optic vibration signal supervisory instrument and method - Google Patents
A kind of fiber-optic vibration signal supervisory instrument and method Download PDFInfo
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- CN106949954B CN106949954B CN201710154455.2A CN201710154455A CN106949954B CN 106949954 B CN106949954 B CN 106949954B CN 201710154455 A CN201710154455 A CN 201710154455A CN 106949954 B CN106949954 B CN 106949954B
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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
Abstract
The invention discloses a kind of fiber-optic vibration signal supervisory instrument and method, device includes narrowband coherent source, photoswitch, optical circulator, Optical Fiber Sensing Array, the first fiber coupler, delay optical fiber, connection optical fiber, the second fiber coupler, the first smooth kerr medium, the second smooth kerr medium, third fiber coupler, balanced detector and data acquisition and Control card.Method is interfered again after carrying out nonlinear phase shift to two-way interference light respectively using two light kerr mediums, and then the narrow band light that photoswitch issues narrowband coherent source is controlled by signal acquisition and controlling board and is modulated, pulse narrow band light is formed, the output signal by acquiring balanced detector obtains the size of transducing signal.The present invention realizes do not use activated amplifier in the case where amplification to transducing signal, improve the phse sensitivity of transducing signal；The complexity that system signal processing equipment is reduced while improving the responsiveness of system, thereby reduces system cost.
Description
Technical field
The invention belongs to technical field of optical fiber sensing, and in particular to a kind of fiber-optic vibration signal supervisory instrument and method.
Background technique
Distributed vibration detection has very big application potential and broad mass market in practical engineering applications.Currently in large size
Monitoring structural health conditions, power cable safety monitoring, the fields such as monitoring pipeline safety, circumference security protection obtain more and more extensive answer
With.Distributed optical fiber vibration sensing is due to having many advantages, such as that distance sensing is remote, anti-electromagnetic interference, senses compared to traditional electric class
System has unique advantage.But the urgent need of the vibration monitoring with extra long distances such as long-distance pipe, national boundaries security protections, it needs
Distance sensing is expanded to distributed optical fiber vibration detection system.
Traditional extension distributing optical fiber sensing distance method has: using the power of EDFA amplification light source output light, using
Raman distributed amplification system carries out distributed air-defense to signal on sensing optic cable, enhances reflective light intensity using dim light grid array
Degree etc..Firstly, based on the remote distributed optical fiber amplification system of EDFA amplifying technique due to by nonlinear effect and modulation not
The influence of stability limits the peak power output of EDFA, is also improved using EDFA amplification system complexity cost；Its
Secondary Raman distributed amplification system remote distributed vibration detecting system is influenced by the both-end such as light of raman pump light, practical
Detection range shortens half, and whole gain amplifier is not uniform enough, and the cost of Raman amplifiction is very high；Again, it is based on
It is maximum anti-to limit grating due to being influenced by crosstalk between different gratings for the distributed vibration monitor system of dim light grid array
Penetrate rate.
Summary of the invention
The technical problem to be solved by the present invention is to for the letter of existing fiber distribution interference-type vibration signal detection system
Number amplification above shortcomings, propose a kind of fiber-optic vibration signal supervisory instrument and method, utilize the non-of light kerr medium
Linear behavio(u)r improves the phse sensitivity of transducing signal, realizes in the case where not using activated amplifier to transducing signal
Amplification.
Used technical solution is the present invention to solve above-mentioned technical problem:
A kind of optical fiber distribution type vibration detection device, it includes narrowband coherent source, photoswitch, optical circulator, optical fiber biography
Feel array, the first fiber coupler, delay optical fiber, connection optical fiber, the second fiber coupler, third fiber coupler, balance to visit
Survey device and data acquisition and Control card, first port of the narrowband coherent source through photoswitch connection optical circulator；Optical circulator
Second port connect Optical Fiber Sensing Array, the first port of the third port of optical fiber circulator and the first fiber coupler connects
It connects, the delayed optical fiber of the second port of the first fiber coupler is connect with the first port of the second fiber coupler, the first optical fiber
The third port of coupler is connect through connection optical fiber with the second port of the second fiber coupler；The third of second fiber coupler
The smooth kerr medium in port first is connect with the first port of third fiber coupler, the 4th port warp of the second fiber coupler
Second smooth kerr medium is connect with the second port of third fiber coupler；The third port of third fiber coupler and the 4th end
Mouth is connected respectively to the first input port, the second input port of balanced detector, delivery outlet and the data acquisition of balanced detector with
The first port of Control card connects, and data acquisition is connected to the input port of photoswitch with the second port of Control card.
According to the above scheme, the delay fiber lengths are 2 times of adjacent weak reflector element interval in Optical Fiber Sensing Array.
According to the above scheme, the described first smooth kerr medium and the second smooth kerr medium structural parameters are consistent.
According to the above scheme, the narrowband coherent source is semiconductor narrow band laser or narrow band fiber laser.
According to the above scheme, the photoswitch is electrooptic modulator or acousto-optic modulator or semiconductor optical amplifier or magnetic
Photoswitch or electroabsorption modulator.
According to the above scheme, the Optical Fiber Sensing Array is the bragg grating array or antiradar reflectivity of antiradar reflectivity
Reflection mirror array.
The present invention also provides a kind of methods that above-mentioned fiber-optic vibration signal supervisory instrument realizes vibration signal detection, including
Following steps:
1) the narrowband coherent light of narrowband coherent source output is modulated into pulse coherence narrow band light after photoswitch；
2) pulse coherence narrow band light is incident on the first port of optical fiber circulator, then from the second port of optical fiber circulator
It is coupled to the Optical Fiber Sensing Array being made of several weak reflector elements after outgoing；
3) after the pulse coherence narrow band light of Optical Fiber Sensing Array reflection returns to optical fiber circulator, pass through optical fiber circulator
It is coupled to the first port of the first fiber coupler after third port outgoing, two pulses phase is divided by the first fiber coupler
Dry light, respectively the first pulse coherence light and the second pulse coherence light, the electricity of the first pulse coherence light and the second pulse coherence light
Field E1、E2It is expressed asWithWherein R is the weak anti-of Optical Fiber Sensing Array
The reflectivity of unit is penetrated, E is the electric field of narrowband coherent source emergent light,WithRespectively the first pulse coherence light and the second arteries and veins
Rush the phase shift transmission of coherent light；
First pulse coherence light is after the outgoing of the second port of the first fiber coupler by delay fiber coupling to second
The first port of fiber coupler, the second pulse coherence light is after the outgoing of the third port of the first fiber coupler by connecting light
Fibre is incident on the second port of the second fiber coupler, and the first pulse coherence light and the second pulse coherence light are in the second fiber coupling
It is interfered in device, passes through the electric field E of the third port output light of the second fiber coupler3With the electric field of the 4th port output light
E4It is respectively as follows:
E3By being incident on the first port of third fiber coupler, E after the first smooth kerr medium4Pass through the second smooth Ke Er
The second port of third fiber coupler, E are incident on after medium3With E4It interferes in third fiber coupler, then passes through
The third port of third fiber coupler and the 4th port output electric field are E5And E6Two-beam, wherein electric field E5With electric field E6
It is respectively as follows:
Wherein, K is the nonlinear factor of the first smooth kerr medium and the second smooth kerr medium, and L is the first smooth kerr medium
With the length of the second smooth kerr medium；
4) first input port of the third port output of third fiber coupler optically coupling to balanced detector, third optical fiber
Second input port of the 4th port output of coupler optically coupling to balanced detector, response of the two-way light in balanced detector
I1,2For
Wherein, I1Take plus sige I2Minus sign is taken, then the output signal I of balanced detector are as follows:
Wherein, P0=| E |2For the input power of light source, the first smooth kerr medium, the second smooth kerr medium parameter selection are full
Foot
5) the output signal I of balanced detector is obtained by signal acquisition and controlling board；
6) narrow band light that photoswitch issues narrowband coherent source is controlled by signal acquisition and controlling board to be modulated,
Pulse narrow band light is formed, the position of reflector element is corresponded to by pulse two-way time orientation sensing signal, is visited by acquisition balance
The output signal I for surveying device obtains the size of transducing signal.
According to the above scheme, in the step 2), weak reflection of the wavelength of pulse coherence narrow band light in Optical Fiber Sensing Array
Among the reflectance spectrum area of unit.
According to the above scheme, in the step 3), delay fiber lengths are between adjacent weak reflector element in Optical Fiber Sensing Array
Every 2 times.
The invention has the benefit that
1, interfere again after carrying out nonlinear phase shift respectively to two-way interference light using two light kerr mediums, utilize
The non-linear nature of light kerr medium improves the phse sensitivity of interference sensing signal, realizes and do not use activated amplifier
In the case where amplification to transducing signal；
2, due to not needing to improve the responsiveness and distance sensing of system using traditional optical amplifier, system is reduced
The complexity of system signal handling equipment, also further reduced system cost.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of optical fiber distribution type vibration of embodiment of the present invention detection device；
In figure: 1- narrowband coherent source, 2- photoswitch, 3- optical circulator, the first port of 301- optical circulator, 302- light
The second port of circulator, the third port of 303- optical circulator, the weak reflector element of 4-, 5- Optical Fiber Sensing Array, the first light of 6-
Fine coupler, the first port of the first fiber coupler of 601-, the second port of the first fiber coupler of 602-, the first light of 603-
The third port of fine coupler, 7- postpone optical fiber, 8- connection optical fiber, the second fiber coupler of 9-, the second fiber coupler of 901-
First port, the second port of the second fiber coupler of 902-, the third port of the second fiber coupler of 903-, 904- second
4th port of fiber coupler, the smooth kerr medium of 10- first, the smooth kerr medium of 11- second, 12- third fiber coupler,
The first port of 121- third fiber coupler, the second port of 122- third fiber coupler, 123- third fiber coupler
Third port, the 4th port of 124- third fiber coupler, 13- balanced detector, the first of 131- balanced detector be defeated
Entrance, the second input port of 132- balanced detector, the delivery outlet of 133- balanced detector, 14- signal acquisition and controlling board,
The first port of 141- signal acquisition and controlling card, the second port of 142- signal acquisition and controlling card.
Specific embodiment
With reference to the accompanying drawings and embodiments to principles and features of the present invention further description.
As shown in Figure 1, optical fiber distribution type vibration detection device described in the embodiment of the present invention, it includes narrowband coherent source
1, photoswitch 2, optical circulator 3, Optical Fiber Sensing Array 5, the first fiber coupler 6, delay optical fiber 7, connection optical fiber 8, the second light
Fine coupler 9, third fiber coupler 12, balanced detector 13 and data acquisition and Control card 14, narrowband coherent source 1 pass through
The first port 301 of the connection optical circulator 3 of photoswitch 2；The second port 302 of optical circulator 3 connects Optical Fiber Sensing Array 5, light
The third port 303 of fine circulator 3 is connect with the first port 601 of the first fiber coupler 6, and the of the first fiber coupler 6
The delayed optical fiber 7 of Two-port netwerk 602 is connect with the first port 901 of the second fiber coupler 9, the third of the first fiber coupler 6
Port 603 is connect through connection optical fiber 8 with the second port 902 of the second fiber coupler 9；The third end of second fiber coupler 9
Mouth 903 is connect through the first smooth kerr medium 10 with the first port 121 of third fiber coupler 12, the second fiber coupler 9
4th port 904 is connect through the second smooth kerr medium 11 with the second port 122 of third fiber coupler 12；Third fiber coupling
The third port 123 of device 12 and the 4th port 124 are connected respectively to the first input port 131, second input of balanced detector 13
Mouth 132, the delivery outlet 133 of balanced detector 13 is acquired with data to be connect with the first port 141 of Control card 14, data acquisition
The input port of photoswitch 2 is connected to the second port 142 of Control card 14.
Narrowband coherent source 1 is semiconductor narrow band laser or narrow band fiber laser.
Photoswitch 2 is electrooptic modulator or acousto-optic modulator or semiconductor optical amplifier or magneto-optic shutter or electric absorption
Modulator.
Optical Fiber Sensing Array 5 is the bragg grating array of antiradar reflectivity or the reflection mirror array of antiradar reflectivity.
The method that fiber-optic vibration signal supervisory instrument of the present invention realizes vibration signal detection, comprising the following steps:
1) the narrowband coherent light that narrowband coherent source 1 exports is modulated into pulse coherence narrow band light after photoswitch 2；
2) pulse coherence narrow band light is incident on the first port 301 of optical fiber circulator 3, then from the of optical fiber circulator 3
Two-port netwerk 302 is coupled to the Optical Fiber Sensing Array 5 being made of several weak reflector elements 4 after being emitted；
Wherein, in the reflectance spectrum area of weak reflector element 4 of the wavelength of pulse coherence narrow band light in Optical Fiber Sensing Array 5
Between；
3) after the pulse coherence narrow band light that Optical Fiber Sensing Array 5 reflects returns to optical fiber circulator 3, pass through optical fiber circulator
3 third port 303 is coupled to the first port 601 of the first fiber coupler 6 after being emitted, divided by the first fiber coupler 6
At two pulses coherent light, respectively the first pulse coherence light and the second pulse coherence light, the first pulse coherence light and the second arteries and veins
The electric field strength for rushing coherent light is expressed as E1、E2；
First pulse coherence light is coupled to after the outgoing of the second port 602 of the first fiber coupler 6 by postponing optical fiber 7
The first port 901 of second fiber coupler 9, the second pulse coherence light are emitted from the third port 603 of the first fiber coupler 6
The second port 902 for being incident on the second fiber coupler 9 by connecting optical fiber 8 afterwards, the first pulse coherence light and the second pulsion phase
Dry light interferes in the second fiber coupler 9, is then exported respectively by the third port 903 of the second fiber coupler 9
The electric field E of light3With the electric field E of 904 output light of the 4th port4, wherein delay 7 length of optical fiber is adjacent in Optical Fiber Sensing Array 5
2 times of the weak interval of reflector element 4；
E3By the first port 121, E for being incident on third fiber coupler 12 after the first smooth kerr medium 104Pass through second
The second port 122 of third fiber coupler 12, the first smooth kerr medium 10 and the second light gram are incident on after light kerr medium 11
Your 11 structural parameters of medium are just the same, E3With E4It is interfered in third fiber coupler 12, forms two-way interference light, point
Not Wei first via interference light and the second tunnel interference light, first via interference light and the second tunnel interference light pass through third fiber coupling respectively
The third port 123 of device 12 and the 4th port 124 output electric field are E5And E6Two-beam；
4) first via interference is optically coupling to the first input port 131 of balanced detector 13, and the interference of the second tunnel is optically coupling to flat
Second input port 132 of weighing apparatus detector 13, response of the two-way interference light in balanced detector 13 is respectively I1,2；Balance detection
The output signal of device 13 is I；
5) the output signal I of balanced detector 13 is obtained by signal acquisition and controlling board 14；
6) photoswitch 2 is controlled by signal acquisition and controlling board 14 to carry out the narrow band light that narrowband coherent source 1 issues
Modulation forms pulse narrow band light, the position of reflector element is corresponded to by pulse two-way time orientation sensing signal, flat by acquiring
The output signal I of weighing apparatus detector 13 obtains the size of transducing signal.
It repeats above operation, distributed vibration signal detection long-term in real time can be carried out.
The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all in spirit of the invention and
Principle etc, any modification, equivalent replacement, improvement and so on should all be included in the protection scope of the present invention.
Claims (9)
1. a kind of optical fiber distribution type vibration detection device, which is characterized in that it includes narrowband coherent source, photoswitch, ring of light shape
Device, Optical Fiber Sensing Array, the first fiber coupler, delay optical fiber, connection optical fiber, the second fiber coupler, third fiber coupling
Device, balanced detector and data acquisition and Control card, first port of the narrowband coherent source through photoswitch connection optical circulator；
The second port of optical circulator connects Optical Fiber Sensing Array, the third port of optical fiber circulator and the first of the first fiber coupler
Port connection, the delayed optical fiber of the second port of the first fiber coupler are connect with the first port of the second fiber coupler, the
The third port of one fiber coupler is connect through connection optical fiber with the second port of the second fiber coupler；Second fiber coupler
Third port connect through the first smooth kerr medium with the first port of third fiber coupler, the 4th of the second fiber coupler the
The smooth kerr medium in port second is connect with the second port of third fiber coupler；The third port of third fiber coupler and
4th port is connected respectively to the first input port of balanced detector, the second input port, the delivery outlet and data of balanced detector
Acquisition is connect with the first port of Control card, and data acquisition is connected to the input of photoswitch with the second port of Control card
Mouthful.
2. optical fiber distribution type vibration detection device according to claim 1, which is characterized in that the delay fiber lengths are
2 times of adjacent weak reflector element interval in Optical Fiber Sensing Array.
3. optical fiber distribution type vibration detection device according to claim 1, which is characterized in that the first smooth kerr medium
It is consistent with the second smooth kerr medium parameter.
4. optical fiber distribution type vibration detection device according to claim 1, which is characterized in that the narrowband coherent source is
Semiconductor narrow band laser or narrow band fiber laser.
5. optical fiber distribution type vibration detection device according to claim 1, which is characterized in that the photoswitch is electric light tune
Device or acousto-optic modulator or semiconductor optical amplifier or magneto-optic shutter or electroabsorption modulator processed.
6. optical fiber distribution type vibration detection device according to claim 1, which is characterized in that the Optical Fiber Sensing Array is
The bragg grating array of antiradar reflectivity or the reflection mirror array of antiradar reflectivity.
7. a kind of realize vibration signal according to the described in any item optical fiber distribution type vibration detection devices of the claims 1~6
The method of detection, which comprises the following steps:
1) the narrowband coherent light of narrowband coherent source output is modulated into pulse coherence narrow band light after photoswitch；
2) pulse coherence narrow band light is incident on the first port of optical fiber circulator, is then emitted from the second port of optical fiber circulator
It is coupled to the Optical Fiber Sensing Array being made of several weak reflector elements afterwards；
3) after the pulse coherence narrow band light of Optical Fiber Sensing Array reflection returns to optical fiber circulator, pass through the third of optical fiber circulator
It is coupled to the first port of the first fiber coupler after the outgoing of port, it is relevant to be divided into two pulses by the first fiber coupler
Light, respectively the first pulse coherence light and the second pulse coherence light, the electric field of the first pulse coherence light and the second pulse coherence light
E1、E2It is expressed asWithWherein R is the weak reflection of Optical Fiber Sensing Array
The reflectivity of unit, E are the electric field of narrowband coherent source emergent light,WithRespectively the first pulse coherence light and the second pulse
The phase shift transmission of coherent light；
First pulse coherence light is after the outgoing of the second port of the first fiber coupler by delay fiber coupling to the second optical fiber
The first port of coupler, the second pulse coherence light enter after the outgoing of the third port of the first fiber coupler by connecting optical fiber
It is mapped to the second port of the second fiber coupler, the first pulse coherence light and the second pulse coherence light are in the second fiber coupler
It interferes, passes through the electric field E of the third port output light of the second fiber coupler3With the electric field E of the 4th port output light4Point
Not are as follows:
E3By being incident on the first port of third fiber coupler, E after the first smooth kerr medium4Pass through the second smooth kerr medium
It is incident on the second port of third fiber coupler, E afterwards3With E4It is interfered in third fiber coupler, then passes through third
The third port of fiber coupler and the 4th port output electric field are E5And E6Two-beam, wherein electric field E5With electric field E6Respectively
Are as follows:
Wherein, K is the nonlinear factor of the first smooth kerr medium and the second smooth kerr medium, and L is the first smooth kerr medium and
The length of two smooth kerr mediums；
4) first input port of the third port output of third fiber coupler optically coupling to balanced detector, third fiber coupling
Second input port of the 4th port output of device optically coupling to balanced detector, response I of the two-way light in balanced detector1,2
For
Wherein, I1Take plus sige I2Minus sign is taken, then the output signal I of balanced detector are as follows:
Wherein, P0=| E |2For the input power of light source, the first smooth kerr medium, the second smooth kerr medium parameter selection meet
5) the output signal I of balanced detector is obtained by signal acquisition and controlling board；
6) narrow band light that photoswitch issues narrowband coherent source is controlled by signal acquisition and controlling board to be modulated, formed
Pulse narrow band light, by pulse two-way time orientation sensing signal from reflector element position, pass through acquisition balance detection
The output signal I of device obtains the size of transducing signal.
8. the method that optical fiber distribution type vibration detection device according to claim 7 realizes vibration signal detection, feature
It is, in the step 2), the reflectance spectrum area of weak reflector element of the wavelength of pulse coherence narrow band light in Optical Fiber Sensing Array
It is intermediate.
9. the method that optical fiber distribution type vibration detection device according to claim 7 realizes vibration signal detection, feature
It is, in the step 3), delay fiber lengths are 2 times of adjacent weak reflector element interval in Optical Fiber Sensing Array.
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| CN109724685B (en) * | 2018-12-10 | 2021-01-19 | 武汉理工大学 | Fiber grating underwater acoustic sensing array demodulation method and system based on Fizeau interference |
| CN111623866B (en) * | 2020-04-23 | 2021-05-14 | 山西大学 | Device and method for measuring vibration mode of nano optical fiber |
| CN114323251B (en) * | 2022-03-10 | 2022-06-17 | 武汉理工大学 | Signal equalization device and method for distributed optical fiber phase-sensitive optical time domain reflectometer |
| CN117109721B (en) * | 2023-10-25 | 2024-01-30 | 之江实验室 | Scattering point position searching device, searching method and demodulation method in DAS system |
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