CN101319921A - Method and equipment for optical fibre optical grating sensing network demodulation - Google Patents

Method and equipment for optical fibre optical grating sensing network demodulation Download PDF

Info

Publication number
CN101319921A
CN101319921A CNA2008101200230A CN200810120023A CN101319921A CN 101319921 A CN101319921 A CN 101319921A CN A2008101200230 A CNA2008101200230 A CN A2008101200230A CN 200810120023 A CN200810120023 A CN 200810120023A CN 101319921 A CN101319921 A CN 101319921A
Authority
CN
China
Prior art keywords
fiber
bragg grating
port
light
sensor fibre
Prior art date
Application number
CNA2008101200230A
Other languages
Chinese (zh)
Inventor
何赛灵
周斌
Original Assignee
浙江大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 浙江大学 filed Critical 浙江大学
Priority to CNA2008101200230A priority Critical patent/CN101319921A/en
Publication of CN101319921A publication Critical patent/CN101319921A/en

Links

Abstract

The invention relates to a method and a device for demodulating a fiber grating sensing network. In the invention, an acoustooptic modulator is connected with a Sagnac loop; an FBG sensing network formed by connecting a plurality of sensing FBGs in series is connected with the Sagnac loop by a three-port 3-dB fiber coupler; the bragg wavelengths of each reference FBG on a reference FBG array are the same as the sensing FBGs with same sequence numbers. The acoustooptic modulator is driven by a RF signal the frequencies of which can be modulated. When the frequencies of the RF signal are changed, the transmittance of the Sagnac loop is changed; the change of the transmittance is detected by a photodiode; the drift amount of the bragg wavelengths of each sensing FBG on the sensing network is obtained by carrying out fast Fourier transformation and relevant operations on the collected data and finally the change of the sensed physical quantity is obtained. The invention can have an extremely high response speed for meeting the requirements of real time sensing; besides, as the sensing network is connected with the Sagnac loop, the performances of anti-external temperature fluctuation and anti-mechanical disturbance of the device are high.

Description

A kind of method and apparatus of optical fiber optical grating sensing network demodulation
Technical field
The invention belongs to technical field of optical fiber sensing, be applicable to the field of the real-time sensing network that needs multinode, high precision, anti-electromagnetic interference (EMI).Be particularly related to a kind of novel acousto-optic modulator change frequency of light wave that utilizes and caused that Sarnia gram asymmetric effect of (Sagnac) ring structure and Fiber Bragg Grating FBG (FBG) hypotenuse detection technique realize the method for FBG sensing network frequency-domain demodulation and the equipment of realizing this method.
Background technology
FBG owing to its distinctive inside of optical fibre sensitivity, Wavelength-encoding, be easy to a kind of important devices that advantages such as networking become Fibre Optical Sensor.Based on wavelength-division multiplex that has grown up (WDM) and Time Division Multiplexing technology, optical fiber optical grating array is widely used in the quasi-distributed sensing of optical fiber, as: the health monitoring of railway, bridge, dam etc., the monitoring temperature that the trunk power transmission line is along the line.Wherein, WDM need to require a wavelength sensitive system of overlapping relative complex to carry out the demultiplexing of multiplexed signals, as: adjustable Fabry Perot wave filter, wavelength sensitive coupling mechanism etc.And in TDM, generally adopt burst pulse light source input, the reflected light signal of each FBG sensor to utilize different time-delays to realize signal multiplexing, use the high-speed photodiode received pulse, and with the high-speed door treatment circuit demultiplexing of demodulating end.This two covers multiplex technique all needs higher light source of cost and complicated demodulating system, has directly caused the cost of FBG sensing network high, has limited its a lot of practical applications.
Acousto-optic modulator utilizes Doppler effect, can accurately change the frequency through the light wave of modulator within the specific limits, is a kind of optical frequency translation device commonly used in the industry; Sagnac ring is because the symmetry of its structure, temperature variation to external world, and mechanical vibration etc. are disturbed insensitive, and at Fibre Optical Sensor, fields such as optical fiber detection are used very extensive; The quasi-distributed sensing network of FBG that the use Sagnac interferometer that change is changeed based on the acousto-optic modulator optical frequency is realized, simple in structure, strong interference immunity does not need photovalve at a high speed, and cost is very low, therefore is highly suitable for practical application.
Summary of the invention
Purpose of the present invention is exactly at the deficiencies in the prior art, uses the Sagnac structure of asymmetric frequency displacement, has proposed a kind of solution that realizes the novel quasi-distributed sensing network of frequency domain FBG.Use wideband light source, low speed photo diodes, low speed data capture card and Fourier frequency meter, and asymmetric Sagnac structure is as the system core element have the advantage that low cost, anti-interference are good, simple and practical, can realize real-time detection.The equipment of realizing this method is provided simultaneously.
Method of the present invention may further comprise the steps:
1, centre wavelength enters in the Sarnia gram ring after light beam that the wideband light source of optical communicating waveband sends is by fibre optic isolater and four port 3-dB fiber couplers.
2, light beam is divided into two-way after entering Sarnia gram ring, wherein one the tunnel enter the known measuring section single-mode fiber of length, incide the optical fiber Bragg grating sensing network that the sensor fibre Bragg grating by a plurality of different bragg wavelengths is connected into by the three port 3-dB fiber couplers that insert in the measuring section single-mode fiber again; Light beam is by each sensor fibre Bragg grating reflection on the sensing network, and reflected light has comprised the reflectance spectrum of all sensor fibre Bragg gratings; Reflection back light beam is got back to the measuring section single-mode fiber through three port 3-dB fiber couplers, produces frequency conversion by acousto-optic modulator, and the sinusoidal signal generator that described acousto-optic modulator is modulated by frequency drives; Light beam after the frequency conversion is got back to four port 3-dB fiber couplers through the known linkage section single-mode fiber of length; Phase place recruitment Δ φ when i sensor fibre Bragg grating beam reflected got back to four port 3-dB fiber couplers on the sensing network 1-iFor:
Δ φ 1 - i = 2 πn [ L a + 2 L i C v i + L b C ( v i + Δv ) ] - - - ( 1 )
Wherein n is the refractive index of single-mode fiber, and C is the light velocity, v iBe the optical frequency of the bragg wavelength correspondence of i sensor fibre Bragg grating, Δ v is the driving frequency of acousto-optic modulator, L iBe the fiber lengths between i sensor fibre Bragg grating on the sensing network and the three port 3-dB fiber couplers, L aBe the length of measuring section single-mode fiber, L bBe the length of linkage section single-mode fiber, L a>>L b
Another road light beam at first passes through the known linkage section single-mode fiber of length, produces frequency conversion by acousto-optic modulator then, and the light beam after the frequency conversion enters the known measuring section single-mode fiber of length; Light beam incides the optical fiber Bragg grating sensing network by the three port 3-dB fiber couplers that insert in the measuring section single-mode fiber, light beam is by each sensor fibre Bragg grating reflection on the sensing network, reflection back light beam is got back to the measuring section single-mode fiber through three port 3-dB fiber couplers, returns four port 3-dB fiber couplers; The phase place recruitment Δ φ of light beam when i sensor fibre Bragg grating beam reflected got back to four port 3-dB fiber couplers on the sensing network 2-iFor:
Δ φ 2 - i = 2 πn [ L b C v i + L a + 2 L i C ( v i + Δv ) ] + π - - - ( 2 )
The two light beams of i Fiber Bragg Grating FBG correspondence interferes in four port 3-dB fiber couplers, the phase delta phi of the light beam of transmission T-iFor:
Δ φ T - i = 2 πn L a + 2 L i - L b C Δv + π - - - ( 3 )
3, the light beam through Sarnia gram ring incides the Fiber Bragg Grating FBG referential array that is connected into by a plurality of reference optical fiber Bragg gratings by optical fiber circulator, each reference optical fiber Bragg grating in the Fiber Bragg Grating FBG referential array is corresponding one by one with each sensor fibre Bragg grating in the optical fiber Bragg grating sensing network, and corresponding reference optical fiber Bragg grating is identical with the bragg wavelength of sensor fibre Bragg grating.
4, the driving frequency Δ v of acousto-optic modulator makes linear change according to ω t, by linear sweep, by the light intensity that transmits Sagnac ring of each sensor fibre Bragg grating beam reflected respectively by cos (f iT) change
f i t = 2 πn L a + 2 L i - L b C ωt - - - ( 4 )
F wherein iFrequency for the light intensity variation.
Photodiode is converted into electric signal with light intensity signal, is gathered by data collecting card, and carries out fast Fourier transform (FFT), obtains each corresponding peak of formula (4) on frequency spectrum, by measuring the frequency f at each peak iThe position L of the sensor fibre Bragg grating that obtains each peak correspondence on the optical fiber Bragg grating sensing network i
L i = ( Cf i 2 πnω - L a + L b ) / 2 - - - ( 5 )
5, on the frequency spectrum intensity at each peak by the position extent decision of each sensing FBG centre wavelength of correspondence with the centre wavelength of the reference FBG identical with its sequence number.Stress application on each sensor fibre Bragg grating successively makes centre wavelength to the drift of long wave direction, the relation of the intensity change at each corresponding peak on the amount of movement of records center wavelength and the frequency spectrum.
6, each Fiber Bragg Grating FBG is installed in the environment that needs sensing, when measured physical quantity changed in the environment, the centre wavelength of each sensor fibre Bragg grating was moved, and caused that the intensity of peak value corresponding on the frequency spectrum changes; The relation of the intensity change at each corresponding peak on amount of movement and the frequency spectrum according to the centre wavelength of record obtains the amount of movement of each Fiber Bragg Grating FBG centre wavelength, finally obtains the environmental physics amount of each Fiber Bragg Grating FBG institute sensing.
The wavelength shift of the centre wavelength of Fiber Bragg Grating FBG and be prior art to the pass between the environmental physics quantitative changeization of inductive sensing (variations such as little curved, temperature, stress).
The equipment of realizing such scheme is: centre wavelength is connected by the input port light of fibre optic isolater with four port 3-dB fiber couplers at the wideband light source of optical communicating waveband, the output port of four port 3-dB fiber couplers is connected with the input port of optical fiber circulator, the output port of optical fiber circulator is connected with the input end light of photodiode, photodiode output is electrically connected with the input end of data collecting card, the output terminal of data collecting card is electrically connected with the fast fourier transform analyser, and the Centronics port of optical fiber circulator is connected with Fiber Bragg Grating FBG referential array light;
Two other port of four port 3-dB fiber couplers connects by single-mode fiber, and single-mode fiber is divided into two sections by acousto-optic modulator, is respectively measuring section single-mode fiber and linkage section single-mode fiber, and length is respectively L aAnd L b, L a>>L b, the electric drive signal mouth of acousto-optic modulator is electrically connected with sinusoidal signal generator; Insert three port 3-dB fiber couplers in the measuring section single-mode fiber, the two-port of the input end of three port 3-dB fiber couplers is connected with the measuring section single-mode fiber respectively, and another port is connected with optical fiber Bragg grating sensing network light;
Described optical fiber Bragg grating sensing network is in series by the sensor fibre Bragg grating of a plurality of different bragg wavelengths, and the bragg wavelength of each sensor fibre Bragg grating is 0.6~1.2nm at interval; Each reference optical fiber Bragg grating in the Fiber Bragg Grating FBG referential array is corresponding one by one with each sensor fibre Bragg grating in the optical fiber Bragg grating sensing network, and corresponding reference optical fiber Bragg grating is identical with the bragg wavelength of sensor fibre Bragg grating.
Among the present invention, acousto-optic modulator can accurately make the light wave generation frequency displacement through modulator within the specific limits.Simultaneously, it is insensitive that the Sarnia gram encircles the interference of temperature variation, mechanical vibration etc. to external world.The present invention is applicable to the quasi-distributed sensing network of general Fiber Bragg Grating FBG, compare with traditional optical fiber Bragg grating sensing network plan, adopted electronic frequency scanning, rather than the Wavelength scanning device of the machinery control of use low speed, can accomplish high response speed, satisfy the requirement of real-time sensing; And owing to do not need short-pulse laser, high-speed photodiode and high-speed data acquisition card, so cost is relatively low; Because sensing network is connected in the Sarnia gram ring, anti-ambient temperature fluctuation of equipment and mechanical disturbance performance are strong in addition.
Description of drawings
Fig. 1 is an one-piece construction synoptic diagram of the present invention;
Fig. 2 is the calibration data of the present invention's one specific embodiment.
Embodiment
As shown in Figure 1, wideband light source 1 is connected with an input port light of four port 3-dB fiber couplers 3 by fibre optic isolater 2; Another input port of four port 3-dB fiber couplers 3 passes through optical fiber circulator 4 and is connected with reference to FBG array 16 light, be in series with reference to FBG 15 by a plurality of with reference to FBG array 16, the output port of optical fiber circulator 4 is connected with the input end light of photodiode 5, the output terminal of photodiode 5 is electrically connected with the input end of data collecting card 6, and the output terminal of data collecting card 6 is electrically connected with fft analysis instrument 7.
Two two other ports of four port 3-dB fiber couplers 3 connect by single-mode fiber, and single-mode fiber is divided into two sections by acousto-optic modulator 9, are respectively measuring section single-mode fiber 12 and linkage section single-mode fiber 8, and length is respectively L aAnd L b, L a>>L bThe electric drive signal mouth of acousto-optic modulator 9 is electrically connected with sinusoidal signal generator 10.The two-port of inserting the input end of three port 3-dB fiber couplers, 11, three port 3-dB fiber couplers 11 in the measuring section single-mode fiber 12 is connected with measuring section single-mode fiber 12 respectively, and another port is connected with sensing network single-mode fiber 13.A plurality of sensing FBG 14 are connected on the sensing network single-mode fiber 13 successively.
Concrete detection method may further comprise the steps:
Centre wavelength enters in the Sarnia gram ring after light beam that the wideband light source of optical communicating waveband sends is by fibre optic isolater and four port 3-dB fiber couplers.
Light beam is divided into two-way after entering Sarnia gram ring, wherein one the tunnel enter the known measuring section single-mode fiber of length, incide the optical fiber Bragg grating sensing network that the sensor fibre Bragg grating by a plurality of different bragg wavelengths is connected into by the three port 3-dB fiber couplers that insert in the measuring section single-mode fiber again; Light beam is by each sensor fibre Bragg grating reflection on the sensing network, and reflected light has comprised the reflectance spectrum of all sensor fibre Bragg gratings; Reflection back light beam is got back to the measuring section single-mode fiber through three port 3-dB fiber couplers, produces frequency conversion by acousto-optic modulator, and the sinusoidal signal generator that described acousto-optic modulator is modulated by frequency drives; Light beam after the frequency conversion is got back to four port 3-dB fiber couplers through the known linkage section single-mode fiber of length; Phase place recruitment Δ φ when i sensor fibre Bragg grating beam reflected got back to four port 3-dB fiber couplers on the sensing network 1-iFor:
Δ φ 1 - i = 2 πn [ L a + 2 L i C v i + L b C ( v i + Δv ) ] - - - ( 1 )
Wherein n is the refractive index of single-mode fiber, and C is the light velocity, v iBe the optical frequency of the bragg wavelength correspondence of i sensor fibre Bragg grating, Δ v is the driving frequency of acousto-optic modulator, L iBe the fiber lengths between i sensor fibre Bragg grating on the sensing network and the three port 3-dB fiber couplers, L aBe the length of measuring section single-mode fiber, L bBe the length of linkage section single-mode fiber, L a>>L b
Another road light beam at first passes through the known linkage section single-mode fiber of length, produces frequency conversion by acousto-optic modulator then, and the light beam after the frequency conversion enters the known measuring section single-mode fiber of length; Light beam incides the optical fiber Bragg grating sensing network by the three port 3-dB fiber couplers that insert in the measuring section single-mode fiber, light beam is by each sensor fibre Bragg grating reflection on the sensing network, reflection back light beam is got back to the measuring section single-mode fiber through three port 3-dB fiber couplers, returns four port 3-dB fiber couplers; The phase place recruitment Δ φ of light beam when i sensor fibre Bragg grating beam reflected got back to four port 3-dB fiber couplers on the sensing network 2-iFor:
Δ φ 2 - i = 2 πn [ L b C v i + L a + 2 L i C ( v i + Δv ) ] + π - - - ( 2 )
The two light beams of i Fiber Bragg Grating FBG correspondence interferes in four port 3-dB fiber couplers, the phase delta phi of the light beam of transmission T-iFor:
Δ φ T - i = 2 πn L a + 2 L i - L b C Δv + π - - - ( 3 )
The light beam that sees through Sarnia gram ring incides the Fiber Bragg Grating FBG referential array that is connected into by a plurality of reference optical fiber Bragg gratings by optical fiber circulator, each reference optical fiber Bragg grating in the Fiber Bragg Grating FBG referential array is corresponding one by one with each sensor fibre Bragg grating in the optical fiber Bragg grating sensing network, and corresponding reference optical fiber Bragg grating is identical with the bragg wavelength of sensor fibre Bragg grating.
The driving frequency Δ v of acousto-optic modulator makes linear change according to ω t, by linear sweep, by the light intensity that transmits Sagnac ring of each sensor fibre Bragg grating beam reflected respectively by cos (f iT) change
f i t = 2 πn L a + 2 L i - L b C ωt - - - ( 4 )
F wherein iFrequency for the light intensity variation.
Photodiode is converted into electric signal with light intensity signal, is gathered by data collecting card, and carries out fast Fourier transform (FFT), obtains each corresponding peak of formula (4) on frequency spectrum, by measuring the frequency f at each peak iThe position L of the sensor fibre Bragg grating that obtains each peak correspondence on the optical fiber Bragg grating sensing network i
L i = ( Cf i 2 πnω - L a + L b ) / 2 - - - ( 5 )
The intensity at each peak is by the position extent decision with the centre wavelength of the reference FBG identical with its sequence number of each sensing FBG centre wavelength of correspondence on the frequency spectrum.As shown in Figure 2, stress application on each sensor fibre Bragg grating successively makes centre wavelength to the drift of long wave direction, the calibration data of the intensity change at each corresponding peak on the amount of movement of records center wavelength and the frequency spectrum.
Each Fiber Bragg Grating FBG is installed in the environment that needs sensing, and when measured physical quantity changed in the environment, the centre wavelength of each sensor fibre Bragg grating was moved, and caused that the intensity of peak value corresponding on the frequency spectrum changes; The relation of the intensity change at each corresponding peak on amount of movement and the frequency spectrum according to the centre wavelength of record obtains the amount of movement of each Fiber Bragg Grating FBG centre wavelength, finally obtains the environmental physics amount of each Fiber Bragg Grating FBG institute sensing.
The wavelength shift of the centre wavelength of Fiber Bragg Grating FBG and be prior art to the pass between the environmental physics quantitative changeization of inductive sensing (variations such as little curved, temperature, stress).

Claims (2)

1, a kind of method of optical fiber optical grating sensing network demodulation is characterized in that the concrete steps of this method are:
A. centre wavelength enters in the Sarnia gram ring after light beam that the wideband light source of optical communicating waveband sends is by fibre optic isolater and four port 3-dB fiber couplers;
B. light beam is divided into two-way after entering Sarnia gram ring, wherein one the tunnel enter the known measuring section single-mode fiber of length, incide the optical fiber Bragg grating sensing network that the sensor fibre Bragg grating by a plurality of different bragg wavelengths is connected into by the three port 3-dB fiber couplers that insert in the measuring section single-mode fiber again; Light beam is by each sensor fibre Bragg grating reflection on the sensing network, and reflected light has comprised the reflectance spectrum of all sensor fibre Bragg gratings; Reflection back light beam is got back to the measuring section single-mode fiber through three port 3-dB fiber couplers, produces frequency conversion by acousto-optic modulator, and the sinusoidal signal generator that described acousto-optic modulator is modulated by frequency drives; Light beam after the frequency conversion is got back to four port 3-dB fiber couplers through the known linkage section single-mode fiber of length; Phase place recruitment Δ φ when i sensor fibre Bragg grating beam reflected got back to four port 3-dB fiber couplers on the sensing network 1-iFor:
Δφ 1 - i = 2 πn [ L a + 2 L i C v i + L b C ( v i + Δv ) ] - - - ( 1 )
Wherein n is the refractive index of single-mode fiber, and C is the light velocity, v iBe the optical frequency of the bragg wavelength correspondence of i sensor fibre Bragg grating, Δ v is the driving frequency of acousto-optic modulator, L iBe the fiber lengths between i sensor fibre Bragg grating on the sensing network and the three port 3-dB fiber couplers, L aBe the length of measuring section single-mode fiber, L bBe the length of linkage section single-mode fiber, L a>>L b
Another road light beam at first passes through the known linkage section single-mode fiber of length, produces frequency conversion by acousto-optic modulator then, and the light beam after the frequency conversion enters the known measuring section single-mode fiber of length; Light beam incides the optical fiber Bragg grating sensing network by the three port 3-dB fiber couplers that insert in the measuring section single-mode fiber, light beam is by each sensor fibre Bragg grating reflection on the sensing network, reflection back light beam is got back to the measuring section single-mode fiber through three port 3-dB fiber couplers, returns four port 3-dB fiber couplers; The phase place recruitment Δ φ of light beam when i sensor fibre Bragg grating beam reflected got back to four port 3-dB fiber couplers on the sensing network 2-iFor:
Δφ 2 - i = 2 πn [ L b C v i + L a + 2 L i C ( v i + Δv ) ] + π - - - ( 2 )
The two light beams of i Fiber Bragg Grating FBG correspondence interferes in four port 3-dB fiber couplers, the phase delta phi of the light beam of transmission T-iFor:
Δφ T - i = 2 πn L a + 2 L i - L b C Δv + π - - - ( 3 )
C. the light beam that sees through Sarnia gram ring incides the Fiber Bragg Grating FBG referential array that is connected into by a plurality of reference optical fiber Bragg gratings by optical fiber circulator, each reference optical fiber Bragg grating in the Fiber Bragg Grating FBG referential array is corresponding one by one with each sensor fibre Bragg grating in the optical fiber Bragg grating sensing network, and corresponding reference optical fiber Bragg grating is identical with the bragg wavelength of sensor fibre Bragg grating;
D. the driving frequency Δ v of acousto-optic modulator makes linear change according to ω t, by linear sweep, by the light intensity that transmits Sagnac ring of each sensor fibre Bragg grating beam reflected respectively by cos (f iT) change
f i t = 2 πn L a + 2 L i - L b C ωt - - - ( 4 )
F wherein iFrequency for the light intensity variation;
Photodiode is converted into electric signal with light intensity signal, is gathered by data collecting card, and carries out fast fourier transform, obtains each corresponding peak of formula (4) on frequency spectrum, by measuring the frequency f at each peak iThe position L of the sensor fibre Bragg grating that obtains each peak correspondence on the optical fiber Bragg grating sensing network i
L i = ( Cf i 2 πnω - L a + L b ) / 2 - - - ( 5 )
E. stress application on each sensor fibre Bragg grating successively makes centre wavelength to the drift of long wave direction, the relation of the intensity change at each corresponding peak on the amount of movement of records center wavelength and the frequency spectrum;
F. each Fiber Bragg Grating FBG is installed in the environment that needs sensing, when measured physical quantity changed in the environment, the centre wavelength of each sensor fibre Bragg grating was moved, and caused that the intensity of peak value corresponding on the frequency spectrum changes; The relation of the intensity change at each corresponding peak on amount of movement and the frequency spectrum according to the centre wavelength of record obtains the amount of movement of each Fiber Bragg Grating FBG centre wavelength, finally obtains the environmental physics amount of each Fiber Bragg Grating FBG institute sensing.
2, the employed equipment of measuring method according to claim 1, it is characterized in that: centre wavelength is connected by the input port light of fibre optic isolater with four port 3-dB fiber couplers at the wideband light source of optical communicating waveband, the output port of four port 3-dB fiber couplers is connected with the input port of optical fiber circulator, the output port of optical fiber circulator is connected with the input end light of photodiode, photodiode output is electrically connected with the input end of data collecting card, the output terminal of data collecting card is electrically connected with the fast fourier transform analyser, and the Centronics port of optical fiber circulator is connected with Fiber Bragg Grating FBG referential array light;
Two other port of four port 3-dB fiber couplers connects by single-mode fiber, and single-mode fiber is divided into two sections by acousto-optic modulator, is respectively measuring section single-mode fiber and linkage section single-mode fiber, and length is respectively L aAnd L b, L a>>L b, the electric drive signal mouth of acousto-optic modulator is electrically connected with sinusoidal signal generator; Insert three port 3-dB fiber couplers in the measuring section single-mode fiber, the two-port of the input end of three port 3-dB fiber couplers is connected with the measuring section single-mode fiber respectively, and another port is connected with optical fiber Bragg grating sensing network light;
Described optical fiber Bragg grating sensing network is in series by the sensor fibre Bragg grating of a plurality of different bragg wavelengths, and the bragg wavelength of each sensor fibre Bragg grating is 0.6~1.2nm at interval; Each reference optical fiber Bragg grating in the Fiber Bragg Grating FBG referential array is corresponding one by one with each sensor fibre Bragg grating in the optical fiber Bragg grating sensing network, and corresponding reference optical fiber Bragg grating is identical with the bragg wavelength of sensor fibre Bragg grating.
CNA2008101200230A 2008-07-15 2008-07-15 Method and equipment for optical fibre optical grating sensing network demodulation CN101319921A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CNA2008101200230A CN101319921A (en) 2008-07-15 2008-07-15 Method and equipment for optical fibre optical grating sensing network demodulation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CNA2008101200230A CN101319921A (en) 2008-07-15 2008-07-15 Method and equipment for optical fibre optical grating sensing network demodulation

Publications (1)

Publication Number Publication Date
CN101319921A true CN101319921A (en) 2008-12-10

Family

ID=40180097

Family Applications (1)

Application Number Title Priority Date Filing Date
CNA2008101200230A CN101319921A (en) 2008-07-15 2008-07-15 Method and equipment for optical fibre optical grating sensing network demodulation

Country Status (1)

Country Link
CN (1) CN101319921A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101908268A (en) * 2010-07-23 2010-12-08 北京交通大学 Optical fiber grating-based monitoring system
CN102095538A (en) * 2011-02-25 2011-06-15 天津大学 Data demodulation method for polarization maintaining fiber stress sensing
CN102322888A (en) * 2011-08-30 2012-01-18 杭州布里特威光电技术有限公司 High-precision optical fiber grating sensing detection structure based on radio frequency optical modulation
CN102322888B (en) * 2011-08-30 2016-12-14 武汉康特圣思光电技术有限公司 A kind of high precision optical fiber grating sensing detection structure based on radio frequency optical modulation
CN107290042A (en) * 2016-04-05 2017-10-24 南京理工大学 The optical fiber grating sensing modulation-demo-demodulation method and device modulated based on phase shift signal

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101908268A (en) * 2010-07-23 2010-12-08 北京交通大学 Optical fiber grating-based monitoring system
CN102095538A (en) * 2011-02-25 2011-06-15 天津大学 Data demodulation method for polarization maintaining fiber stress sensing
CN102095538B (en) * 2011-02-25 2012-02-22 天津大学 Data demodulation method for polarization maintaining fiber stress sensing
CN102322888A (en) * 2011-08-30 2012-01-18 杭州布里特威光电技术有限公司 High-precision optical fiber grating sensing detection structure based on radio frequency optical modulation
CN102322888B (en) * 2011-08-30 2016-12-14 武汉康特圣思光电技术有限公司 A kind of high precision optical fiber grating sensing detection structure based on radio frequency optical modulation
CN107290042A (en) * 2016-04-05 2017-10-24 南京理工大学 The optical fiber grating sensing modulation-demo-demodulation method and device modulated based on phase shift signal
CN107290042B (en) * 2016-04-05 2019-07-12 南京理工大学 Optical fiber grating sensing modulation-demo-demodulation method and device based on phase shift signal modulation

Similar Documents

Publication Publication Date Title
Sun et al. Distributed fiber-optic vibration sensor using a ring Mach-Zehnder interferometer
CN1228610C (en) Sensing and testing fiber grating system for oil and gas pipeline detection
CN101242224B (en) An optical fiber pipe monitoring system
CA2777504C (en) Stimulated brillouin system with multiple fbg's
CN105784195B (en) The distribution type optical fiber sensing equipment and method of single-ended chaos Brillouin optical time domain analysis
CN102914321B (en) Ultra-low fiber bragg grating sensing system and query method thereof
Gholamzadeh et al. Fiber optic sensors
CN103245370B (en) Based on the BOTDA system of pulse code and coherent detection
CN103364070B (en) Fiber bragg grating vibration sensing system based on volume phase grating demodulation
CN102636196B (en) Distributed disturbance sensor on basis of Rayleigh scattering spectrum related coefficient and demodulating method thereof
US20070051882A1 (en) System and method for monitoring a well
US5991026A (en) Apparatus for multiplexing fibre-optic sensing interferometers
CN101246026B (en) Method and device for optical sensor inquiry system
CN102226703B (en) Distributed fiber multi-parameter sensor and multi-parameter measuring method
CN103115632B (en) Multi-wavelength Brillouin optical time-domain analyzer
CN103439766B (en) A kind of space division multiplexing method of multi-core fiber
CN102937416B (en) A kind of fully distributed fiber switched based on orthogonal polarisation state strains and vibration sensing method and device
CN102759371A (en) COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer
CN102636217B (en) Sensing device based on joint detection of Brillouin optical time domain analysis and Mach-Zehnder interference
DE102009025989A1 (en) Fiber optic multiple parameter measurement system and method for a turbomachinery system
CN102116738B (en) Methane gas sensing device based on fiber-loop ring-down cavity
CN105067103A (en) Vibration detection device and method based on optical frequency domain reflectometer
CN102506912A (en) Optical fiber distributed disturbance sensor
US20140211202A1 (en) Optical fibre sensor interrogation system
CN107655561A (en) A kind of phase-modulation demodulating equipment based on optical fiber grating sonic device array

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C12 Rejection of a patent application after its publication
RJ01 Rejection of invention patent application after publication

Open date: 20081210