CN105241390A - Rapid Brillouin optical-time domain analysis type strain measuring device and data processing method - Google Patents

Abstract

The invention relates to a stimulated Brillouin gain spectral linewidth narrowing processing, pulse coding and wavelet transform technology-based high-performance rapid Brillouin optical-time domain analysis type (BOTDA) strain measuring device and a data processing method and belongs to the distributed optical fiber sensing technical field. The measuring device is composed of a laser 1, a first optical coupler 2, a first modulator 3, a first microwave signal source 20, a first optical filter 4, a second modulator 5, a second microwave signal source 21, a direct-current power source 22, an optical amplifier 6, a second optical coupler 7, an optical isolator 8, a second modulator 9, a frequency synthesizer 14, a second optical filter 10, a fourth modulator 11, a pulse signal generator 15, a scrambler 12, an optical circulator 13, a sensing optical fiber 19, a photoelectric detector 16, a data acquisition card 17 and a computer 18. According to the measuring device and the data processing method of the invention, three pump signals are adopted to realize optical fiber stimulated Brillouin scattering gain spectral linewidth narrowing processing, and therefore, the precision of a BOTDA strain measurement system can be improved; pulse encoding and wavelet transform technology are combined to improve a signal-to-noise ratio, and therefore, measurement accuracy can be improved, and measurement time can be shortened.

Description

Quick Brillouin optical time domain analysis type strain gauge means and data processing method

Technical field

The invention belongs to Distributed Optical Fiber Sensing Techniques field, be specifically related to a kind of high-performance fast B OTDA (Brillouin optical time domain analysis type) strain gauge means of combining based on the process of excited Brillouin gain spectrum width, pulse code and wavelet transformation technique and data processing method.

Background technology

Fibre Optical Sensor has the advantages such as volume is little, lightweight, highly sensitive, high pressure resistant, corrosion-resistant, electrical insulating property is good, electromagnetism interference, is widely used in the structure detection such as communications optical cable, river levee, concrete, pipeline, tunnel, bridge.Distributed fiberoptic sensor based on stimulated Brillouin scattering effect utilizes the linear relationship between excited Brillouin frequency shift amount and strain, measure the corresponding strain variation in this position by measuring optical fiber Brillouin shift everywhere, thus realize the distributed measurement of strain.

Excited Brillouin distributed fiberoptic sensor mainly contains three types: Brillouin optical time domain analysis (BOTDA) type, Brillouin light frequency-domain analysis (BOFDA) type and Brillouin scattering optical time domain reflection (BOTDR) type.BOTDA system strains owing to utilizing optical fiber stimulated Brillouin scattering effect measurement, and brillouin gain live width directly has influence on the measuring accuracy of strain, and brillouin gain live width is wider, and the measuring accuracy of strain is lower.The Measuring Time of BOTDA system is also a very crucial factor, the method of the reduction time of current employing adopts coding techniques improve signal to noise ratio (S/N ratio) and then reduce pendulous frequency, shorten Measuring Time, but when the exponent number of coding is too high, the Measuring Time of system is also unfavorable for reducing.

Summary of the invention

The object of this invention is to provide a kind of high performance BOTDA strain gauge means combined based on the process of excited Brillouin gain spectrum width, pulse code and wavelet transformation technique.

The structure of high performance BOTDA strain measurement system of the present invention as shown in Figure 1, by laser instrument 1, first photo-coupler 2, first modulator 3, first microwave signal source 20, first optical filter 4, second modulator 5, second microwave signal source 21, direct supply 22, image intensifer 6, second photo-coupler 7, optoisolator 8, second modulator 9, frequency synthesizer 14, second optical filter 10, 4th modulator 11, pulse signal generator 15, scrambler 12, optical circulator 13, sensor fibre 19, photodetector 16, data collecting card 17 and computing machine 18 form, first modulator 3, second modulator 5, 3rd modulator 9, 4th modulator 11 is intensity modulator.

Laser instrument 1 output frequency is f _clight signal (Fig. 2 (1)) through the first photo-coupler 2 one dividing into three, be designated as the first branch road 101, second branch road 201 and the 3rd branch road 301 respectively, the splitting ratio of the first branch road 101, second branch road 201, the 3rd branch road 301 is 3:3:4, wherein, the light signal of the first branch road is sent in the first modulator 3 as light carrier, is then 2f by the frequency that the first microwave signal source 20 exports _b(f _bstimulated Brillouin scattering frequency shift amount for sensor fibre 19) microwave signal modulation, owing to being microwave signal modulation by a small margin, only consider carrier wave and single order sideband (f _c, f _c+2f _b, f _c-2f _b), the signal that the first modulator 3 exports is input in the first optical filter 4, filters carrier wave and single order upper side band, and only surplus frequency is f _c-2f _bsingle order lower sideband signal (Fig. 2 (2)), be f by the frequency that the first optical filter 4 exports _c-2f _bsignal is sent in the second modulator 5 again, is f by the frequency that the second microwave signal source 21 exports _lsignal madulation, the DC voltage that adjustment direct supply 22 exports changes the DC offset voltage of the second modulator 5, and the double-side band output state making it be operated in carrier wave to suppress, its output frequency is f _c-2f _b+ f _land f _c-2f _b-f _ltwo signals (Fig. 2 (3)), the second modulator 5 outputs signal (f _c-2f _b+ f _land f _c-2f _b-f _l) intensity can be amplified by image intensifer 6; Second branch road 201 medium frequency is f _clight signal and the first branch road 101 in the light signal that amplifies through image intensifer 6 be sent in sensor fibre 19 through optoisolator 8 again after the second photo-coupler 7, as the pump signal of stimulated Brillouin scattering effect in sensor fibre 19, the frequency of three pump signal is respectively f _c, f _c-2f _b+ f _land f _c-2f _b-f _l(intensity can be controlled by image intensifer 6), pump signal f _cthe centre frequency of the gain spectral produced is f _c-f _b, pump signal f _c-2f _b+ f _land f _c-2f _b-f _lthe centre frequency producing loss spectra is f _c-f _b+ f _land f _c-f _b-f _l(Fig. 2 (4)), the enlargement factor changing image intensifer 6 can change pump signal f _c-2f _b+ f _land f _c-2f _b-f _lintensity, thus change loss spectra f _c-f _b+ f _land f _c-f _b-f _lintensity, centre frequency is f _c-f _bgain spectral and centre frequency be f _c-f _b+ f _land f _c-f _b-f _lloss spectra interacts, and realizes the process that narrows (Fig. 2 (5)) of excited Brillouin gain spectral live width, thus improves measuring accuracy.Light signal in 3rd branch road 301 is input in the 3rd modulator 9, is f by the frequency that frequency synthesizer 14 exports _t(f _tfrequency be with f _bcentered by the scope of 300M, press certain frequency interval variation) small amplitude signal modulation, second optical filter 10 filters carrier wave in modulation signal and single order upper side band signal (owing to being small signal modulation, only have carrier wave and single order sideband), a reserve frequency is f _c-f _tsingle order lower sideband signal, frequency is f _c-f _tsignal be input in the 4th modulator 11, (the high level width of pulse signal is 10ns ~ 100ns to the pulse signal modulation exported by pulse signal generator 15, pulsed frequency is 10kHz ~ 100kHz), the signal that 4th modulator 11 exports is input in scrambler 12, scrambler 12 is in order to by the randomization of polarisation of light state, to eliminate the impact of polarization state on stimulated Brillouin scattering effect, through scrambler 12 process light signal as stimulated Brillouin scattering effect in sensor fibre 19 pulsed light from optical circulator 13 I port input, II port enters into sensor fibre 19 after exporting.The pulsed light of three pump signal from the process that narrows of optoisolator 8 output and the II port output from circulator interacts sensor fibre 19, stimulated Brillouin scattering phenomenon can be there is when meeting stimulated Brillouin scattering condition between the difference on the frequency of two-way light, carry port II input of pump light signals through optical circulator of stimulated Brillouin scattering information, detected by photodetector 16 after the port III of optical circulator 13 exports, then by data collecting card 17, the data collected are sent into computing machine 18 to process, the frequency values that computing machine 18 also needs controlled frequency synthesizer 14 to export and pulse signal generator 15 export the initial time of pulse, excited Brillouin gain spectral crest frequency can be obtained finally by spectrum simulation, and then determine the size of strain, the mistiming that the time sent by pulse and gain spectral peak value are occurred can judge to strain the position occurred.

The strain measurement accuracy formula of BOTDA measuring system is wherein, Δ ν _bbrillouin gain spectral line width, SNR is system signal noise ratio, visible, reduces brillouin gain live width Δ ν _bthe measuring accuracy of system all can be improved with increase signal to noise ratio (S/N ratio).

The present invention to combine the to-noise ratio (SNR) that improves system and then raising measuring accuracy and shorten the Measuring Time of system by adopting S-codes (Simplexcodes) coding and wavelet transformation technique.S-codes coding techniques is adopted to be by carrying out Hadamard (hadmard) conversion to s-matrix (S-matrix), then noise decrease is carried out by superposition, improve signal to noise ratio (S/N ratio), S-matrix is a unipolarity matrix, be made up of 1 and 0, S-codes is encoded, when the exponent number of s-matrix increases, decode time is elongated, the Measuring Time of system is increased, adopt the exponent number of suitable s-matrix, after data processing end decodes the data that collect, recycle wavelet transformation technique carry out denoising, the to-noise ratio of raising system and then improve measuring accuracy and shorten the Measuring Time of system.The key of this coding techniques builds S-matrix matrix, with while measuring optical fiber diverse location along the line Brillouin intensity.Illustrating for three rank S-matrix matrixes adopts this coding techniques to improve SNR, supposes for a monopulse P ₁t () is launched in measured optical fiber, the response obtained is ψ ₁(t).Define new pulse P simultaneously ₂(t)=P ₁(t-τ), P ₃(t)=P ₁(t-2 τ), their response is respectively: ψ ₂(t)=ψ ₁(t-τ), ψ ₃(t)=ψ ₁(t-2 τ); Can obtain by launching S-codes sequence:

$P_1\left(t\right)+P_3\left(t\right)\⇒{\mathrm{\η}}_1\left(t\right)={\mathrm{\ψ}}_1\left(t\right)+{\mathrm{\ψ}}_3\left(t\right)+e_1\left(t\right)$

$P_2\left(t\right)+P_3\left(t\right)\⇒{\mathrm{\η}}_2\left(t\right)={\mathrm{\ψ}}_2\left(t\right)+{\mathrm{\ψ}}_3\left(t\right)+e_2\left(t\right)$

$P_1\left(t\right)+P_2\left(t\right)\⇒{\mathrm{\η}}_3\left(t\right)={\mathrm{\ψ}}_1\left(t\right)+{\mathrm{\ψ}}_2\left(t\right)+e_3\left(t\right)$

So S-matrix can be adopted to be write as the form of hadamard conversion:

$\left(\begin{array}{c}{\mathrm{\η}}_1\left(t\right)\\ {\mathrm{\η}}_2\left(t\right)\\ {\mathrm{\η}}_3\left(t\right)\end{array}\right)=S\left(\begin{array}{c}{\mathrm{\ψ}}_1\left(t\right)\\ {\mathrm{\ψ}}_2\left(t\right)\\ {\mathrm{\ψ}}_3\left(t\right)\end{array}\right)+\left(\begin{array}{c}{e}_1\left(t\right)\\ e_2\left(t\right)\\ e_3\left(t\right)\end{array}\right),S=\left(\begin{array}{ccc}1& 0& 1\\ 0& 1& 1\\ 1& 1& 0\end{array}\right)$

In formula, e (t) is the noise measured.From above formula, code length is the exponent number of S-matrix.In order to recover ψ ₁t () needs to carry out Hadmard inverse transformation, obtain following expression:

Then

So the result after processing can be obtained be:

$\begin{array}{c}\mathrm{\Ψ}\left(t\right)={\mathrm{\ψ}}_1\left(t\right)+\frac{e_1\left(t\right)-e_2\left(t\right)+e_3\left(t\right)}{6}+\frac{-e_1(t+\mathrm{\τ})+e_2(t+\mathrm{\τ})+e_3(t+\mathrm{\τ})}{6}\\ +\frac{e_1(t+2\mathrm{\τ})+e_2(t+2\mathrm{\τ})-e_3(t+2\mathrm{\τ})}{6}\end{array}$

Last Mean Square Error is:

$E\left\{{\[\mathrm{\Ψ}\left(t\right)-{\mathrm{\ψ}}_1\left(t\right)\]}^2\right\}=\frac{{\mathrm{\σ}}^2}{4}$

And for common monopulse situation, the Mean Square Error of three iteration is σ ²/ 3, the pattern gain obtained when being 3 for code length is therefore be the S-codes of L for length, the pattern gain can deriving it is

$\frac{L+1}{2\sqrt{L}}$

Thus, the signal to noise ratio (S/N ratio) of system can be made to be promoted to accordingly original doubly.

S-codes is encoded, when the exponent number of s-matrix increases, decode time is elongated, the Measuring Time of system is increased, the present invention adopts the exponent number of suitable s-matrix, after data processing end decodes the data that collect, recycle wavelet transformation technique carry out denoising, greatly can save the time of one-shot measurement.

The denoising of wavelet threshold shrinkage method divides following three steps:

1) orthogonal wavelet transformation of signals and associated noises is calculated.For the signals and associated noises X that length is N, might as well N=2 be established ^j, the scale coefficient { v under utilizing the fast algorithm of orthogonal wavelet transformation to obtain low resolution L (0≤L < J) _l,k, k=1 ..., 2 ^j, and the wavelet coefficient { w under each resolution _j,k, j=L, L+1 ..., J-1, k=1 ..., 2 ^j, wherein scale coefficient and wavelet coefficient N altogether.When processing border, normal employing periodic extension method.

2) non-linear threshold process is carried out to wavelet coefficient.For the global shape of holding signal is constant, retain all low frequency coefficient v _l,k, k=1 ..., 2 ^l.Get threshold value to each wavelet coefficient, hard thresholding method is adopted to process:

Hard-threshold: ${\tilde{w}}_{j,k}=\left\{\begin{array}{c}{w}_{j,k},\left|w_{j,k}\right|\&GreaterEqual;\mathrm{\&lambda;}\\ 0,\left|w_{j,k}\right|<\mathrm{\&lambda;}\end{array}\right.$

That is, the absolute value of the wavelet coefficient of signals and associated noises with the threshold value λ that selectes compare, be less than or equal to the some vanishing of threshold value, the point being greater than threshold value remains unchanged.

3) inverse wavelet transform is carried out.By all low frequency scale coefficients, and do inverse wavelet transform via the wavelet coefficient after threshold process and be reconstructed, the estimated value of the original signal be restored.

Finally, the sudden change peak obtaining the appearance of measured field thus judges to damage the position occurred.

When measuring beginning, the output frequency of laser instrument 1 is set to f _c=193.41THz (corresponding wavelength is 1550nm), computing machine sends instruction initiation culture synthesizer 14 and starts frequency sweep, starting impulse signal generator 15 output pulse width is 10 ~ 100ns simultaneously, frequency is the pulse signal that 10kHz ~ 100kHz encodes by s-matrix, the exponent number of coding can get 3 ~ 255 rank, example is encoded to 3 rank, first its form of pulsed optical signals of first group of sequence is inputted as shown in Fig. 3 (a), computing machine 18 recording pulse signal generator 15 sends the time of pulse signal, this time is for measuring the start time, the excited Brillouin frequency shift amount f of sensor fibre 19 _bbe 9 ~ 11GHz, the centre frequency of frequency synthesizer 14 is set to f _b, swept frequency range is 100 ~ 300MHz, frequency step is 0.1 ~ 0.3MHz, the original frequency of setpoint frequency synthesizer 14, this microwave signal after the 3rd modulator 9 again through the second optical filter 10 filtering, retain sideband signals, then sensor fibre 19 is entered into successively as pulsed light after being modulated by the 4th modulator 11 by the pulse signal shown in Fig. 3 (a), three pump signal that the input of sensor fibre 19 other end can make excited Brillouin live width narrow, the pulsed optical signals of coding is propagated along sensor fibre 19 successively, when the pulsed optical signals of first group of sequence is propagated in sensor fibre 19, the light signal carrying stimulated Brillouin scattering information can be received at the receiving end of photodetector 16, be sent in computing machine 18 through data collecting card 17, the frequency values of holding frequency synthesizer 14, the pulsed optical signals inputting 3 rank s-matrix coded residual is successively shown in Fig. 3 (b) and 3 (c), these signals detected to be decoded in computing machine 18 light intensity obtained along each point on fiber lengths, then in computing machine 18, wavelet transform process is carried out to the response obtained of decoding, just a sweep measurement is completed.Then the frequency step value arranged by frequency synthesizer 14 completes the sweep measurement of each Frequency point successively according to the process of above-mentioned coding and wavelet transform process, finally obtain the change curve that sensor fibre 19 goes up the light intensity frequency values of each point along its length, frequency when brillouin gain reaches maximal value can be obtained by Lorentz fit, maximum frequency values is exactly optical fiber stimulated Brillouin frequency shift amount, due to strain and frequency shift amount linear, and then determine the size of strain, simultaneously, computing machine 18 can judge to strain the position occurred by the mistiming of time and the appearance of gain spectral peak value that pulse signal generator 15 sends pulse, just the location to strain can be realized.

The present invention realizes the process of optical fiber stimulated Brillouin scattering gain spectrum width by employing three pump signal, improves the precision of BOTDA strain measurement system; Adopt pulse code and wavelet transformation technique to combine raising signal to noise ratio (S/N ratio), and then improve measuring accuracy, shorten Measuring Time.

Accompanying drawing explanation

Fig. 1: high-performance BOTDA strain measurement system schematic diagram;

Fig. 2: stimulated Brillouin scattering composes the processing procedure schematic diagram that narrows;

The pulsed optical signals of Fig. 3: three rank codings;

Fig. 4: the response curve that when adopting separately S to encode, different coding order is corresponding;

The response curve that when Fig. 5: S coding and wavelet transformation combine, different coding order is corresponding.

Embodiment

Embodiment 1:

Select the TSL-510 tunable laser of Santec company to make carrier wave light source, the wavelength coverage of laser instrument 1 is 1510nm ~ 1630nm wavelength, and setting wavelength is that (respective frequencies is f to 1550nm _c=193.41THz); First modulator 3, second modulator 5, the 3rd modulator 9 and the 4th modulator 11 are the MXAN-LN-40 of Photline company, and bandwidth is 32GHz; First optical filter 4 and the second optical filter 10 are the adjustable light wave-filter of Santec company, and model is OTF-950, and wavelength tuning range is 1548nm to 1552nm, and live width is less than 10GHz; Image intensifer 6 is the Erbium-Doped Fiber Amplifier (EDFA) of company limited of ZTE Corporation, and wavelength coverage is 1530 ~ 1565nm, and enlargement factor is greater than 35 times; First microwave signal source 20 and the second microwave signal source 21 are the 8257D of Agilent company; Frequency synthesizer 14 is the RJUFS020180-1K of Chengdu Ren Jian microwave technology company limited, and reference frequency output is 2-18GHz; Pulse signal generator 15 is Agilent company 81131A, and frequency range is 1Hz-400MHz; Photodetector 16 is the SD-48 of Imtech, and bandwidth is 35GHz; Sensor fibre 19 is the optical fiber of Yangtze Optical Fiber and Cable Company Ltd, and excited Brillouin gain live width is Γ _b=40MHz, Brillouin shift amount f _b=10GHz, length is 500 meters, and gain and loss peak coefficient are 5; The isolation of optoisolator 8 is greater than 40dB; Scrambler 12 is the PCD-104 of high Micron Technology Co., Ltd; Data collecting card 17 is the PCI-5112 data collecting card of NI company, and sample frequency is 100MSPS.

Corresponding instrument and equipment is connected by Fig. 1, open instrument power source, the wavelength of laser instrument 1 is set as 1550nm, the output frequency of the first microwave signal source 20 is 20GHz, the set of frequency of the second microwave signal source 21 is 20MHz, the enlargement factor of image intensifer 6 is set to 25 times, and by 101 branch roads of Fig. 1 and the effect of 201 branch roads, the live width that excited Brillouin can be made to compose narrows to 4.14MHz.

When measuring beginning, the output frequency of laser instrument 1 is set to f _c=193.41THz (corresponding wavelength is 1550nm), computing machine sends instruction initiation culture synthesizer 14 and starts frequency sweep, starting impulse signal generator 15 output pulse width is 10ns simultaneously, frequency is the pulse signal that 10kHz encodes by s-matrix, the exponent number of coding is set to 3 respectively, 7, 15, 61, 63, 127, 255 rank, computing machine 18 recording pulse signal generator sends the time of pulse signal, this time is for measuring the start time, the excited Brillouin frequency shift amount of optical fiber is 10GHz, the original frequency of setpoint frequency synthesizer 14 is 9.9GHz, swept frequency range is 200MHz, frequency step is 0.1MHz, the microwave signal of this 9.9GHz after the 3rd modulator 9 again through the second optical filter 10 filtering, retain sideband signals f _c-9.9GHz, then by pulse signal generator 15 export by s-matrix coding pulse signal modulated by the 4th modulator 11 after enter into sensor fibre 19 successively as pulsed light, three pump signal that the input of sensor fibre 19 other end can make excited Brillouin live width narrow, propagated along sensor fibre 19 successively by the pulsed optical signals that s-matrix is encoded, when the pulsed optical signals of first group of sequence is propagated in sensor fibre 19, the light signal carrying stimulated Brillouin scattering information can be received at the receiving end of photodetector 16, be sent in computing machine 18 through data collecting card 17, the frequency values 9.9GHz of holding frequency synthesizer 14, remaining pulsed optical signals is inputted successively by the exponent number of s-matrix coding, these signals detected are decoded in computing machine 18 and obtain frequency when being 9.9GHz, along the light intensity of each point in fiber length, then in computing machine 18, wavelet transform process is carried out to the response obtained of decoding, just a sweep measurement is completed.Then the frequency step value arranged by frequency synthesizer 14 completes the sweep measurement within the scope of 200MHz successively according to the process of above-mentioned coding and wavelet transform process, finally obtain the change curve of the light intensity frequency values of each point in sensor fibre 19 length, frequency when brillouin gain reaches maximal value can be obtained by Lorentz fit, maximum frequency values is exactly optical fiber stimulated Brillouin frequency shift amount, due to strain and frequency shift amount linear, and then determine the size of strain, simultaneously, computing machine 18 can judge to strain the position occurred by the mistiming of time and the appearance of gain spectral peak value that pulse signal generator 15 sends pulse, just the location to strain can be realized.

Strain is added at the 470m place of sensor fibre 19, when independent employing 3,7,15,31,63,127,255 rank S encodes, meet with a response curve as shown in Fig. 4 (b)-4 (h) after decoding, response respectively during corresponding 3,7,15,31,63,127,255 rank coding, Fig. 4 (a) is the response curve of decoding when not adopting coding, as can be seen from Fig. 4 (a)-4 (h), when the order of coding is 255 rank, can tell the strain at 470 meters of after decoding, the processing time is now 4439.7244s.

Fig. 5 is the response after code is understood in 3,7,15,31 rank S codings and wavelet transformation junction, Fig. 5 (a)-Fig. 5 (d) is respectively response when 3,7,15,31 rank S codings and wavelet transformation, as can be seen from Figure 5, after coding exponent number is increased to 31 rank decodings, combined with wavelet transformed can tell the strain at 470m place, now, 31 rank codings amount to the processing time in conjunction with wavelet analysis is 45.1673s.Adopt S coding and wavelet transformation to combine and obviously can shorten signal processing time, increase the rapidity of system.

Claims (5)

1. a quick Brillouin optical time domain analysis type strain gauge means, it is characterized in that: by laser instrument (1), first photo-coupler (2), first modulator (3), first microwave signal source (20), first optical filter (4), second modulator (5), second microwave signal source (21), direct supply (22), image intensifer (6), second photo-coupler (7), optoisolator (8), second modulator (9), frequency synthesizer (14), second optical filter (10), 4th modulator (11), pulse signal generator (15), scrambler (12), optical circulator (13), sensor fibre (19), photodetector (16), data collecting card (17) and computing machine (18) composition,

Laser instrument (1) output frequency is f _clight signal through the first photo-coupler (2) one dividing into three, be designated as the first branch road (101), the second branch road (201) and the 3rd branch road (301) respectively, wherein, the light signal of the first branch road (101) is sent in the first modulator (3) as light carrier, is then 2f by the frequency that the first microwave signal source (20) exports _bmicrowave signal modulation, owing to being microwave signal modulation by a small margin, only consider carrier wave and single order sideband, the signal that the first modulator (3) exports is input in the first optical filter (4), filters carrier wave and single order upper side band, and only surplus frequency is f _c-2f _bsingle order lower sideband signal, be f by the frequency that the first optical filter (4) exports _c-2f _bsignal is sent in the second modulator (5) again, is f by the frequency that the second microwave signal source (21) exports _lsignal madulation, adjustment direct supply (22) DC voltage that exports changes the DC offset voltage of the second modulator (5), and the double-side band output state making it be operated in carrier wave to suppress, its output frequency is f _c-2f _b+ f _land f _c-2f _b-f _ltwo signals, the intensity that the second modulator (5) outputs signal can be amplified by image intensifer (6);

Second branch road (201) medium frequency is f _clight signal and the first branch road (101) in the light signal that amplifies through image intensifer (6) be sent in sensor fibre (19) through optoisolator (8) again after the second photo-coupler (7), as the pump signal of stimulated Brillouin scattering effect in sensor fibre (19), the frequency of three pump signal is respectively f _c, f _c-2f _b+ f _land f _c-2f _b-f _l, pump signal f _cthe centre frequency of the gain spectral produced is f _c-f _b, pump signal f _c-2f _b+ f _land f _c-2f _b-f _lthe centre frequency producing loss spectra is f _c-f _b+ f _land f _c-f _b-f _l, the enlargement factor changing image intensifer (6) can change pump signal f _c-2f _b+ f _land f _c-2f _b-f _lintensity, thus change loss spectra f _c-f _b+ f _land f _c-f _b-f _lintensity, centre frequency is f _c-f _bgain spectral and centre frequency be f _c-f _b+ f _land f _c-f _b-f _lloss spectra interacts, and realizes the process that narrows of excited Brillouin gain spectral live width, thus improves measuring accuracy;

Light signal in 3rd branch road (301) is input in the 3rd modulator (9), is f by the frequency that frequency synthesizer (14) exports _tsmall amplitude signal modulation, the second optical filter (10) filters carrier wave in modulation signal and single order upper side band signal, and a reserve frequency is f _c-f _tsingle order lower sideband signal, frequency is f _c-f _tsignal be input in the 4th modulator (11), by the pulse signal modulation that pulse signal generator (15) exports, the signal that 4th modulator (11) exports is input in scrambler (12), scrambler (12) is in order to by the randomization of polarisation of light state, to eliminate the impact of polarization state on stimulated Brillouin scattering effect, the light signal processed through scrambler (12) as the pulsed light of stimulated Brillouin scattering effect in sensor fibre (19) from I port input of optical circulator (13), II port enters into sensor fibre (19) after exporting, from optoisolator (8) export narrow process three pump signal and from circulator II port export pulsed light interact sensor fibre (19), stimulated Brillouin scattering phenomenon can be there is when meeting stimulated Brillouin scattering condition between the difference on the frequency of two-way light, carry port II input of pump light signals through optical circulator of stimulated Brillouin scattering information, detected by photodetector (16) after the port III of optical circulator (13) exports, then by data collecting card (17), the data collected are sent into computing machine (18) process, the frequency values that computing machine (18) also needs controlled frequency synthesizer (14) to export and pulse signal generator (15) export the initial time of pulse, excited Brillouin gain spectral crest frequency can be obtained finally by spectrum simulation, and then determine the size of strain, the mistiming that the time sent by pulse and gain spectral peak value are occurred can judge to strain the position occurred.

2. a kind of Brillouin optical time domain analysis type strain gauge means fast as claimed in claim 1, is characterized in that: the first modulator (3), the second modulator (5), the 3rd modulator (9) and the 4th modulator (11) are intensity modulator.

3. a kind of Brillouin optical time domain analysis type strain gauge means fast as claimed in claim 1, is characterized in that: the splitting ratio of the first branch road (101), the second branch road (201) and the 3rd branch road (301) is 3:3:4.

4. the data processing method of a quick Brillouin optical time domain analysis type strain gauge means, it is characterized in that: by adopting S-codes coding and wavelet transformation technique to combine and improve the to-noise ratio of this device, and then raising measuring accuracy and shorten the Measuring Time of system.

5. the data processing method of a kind of quick Brillouin optical time domain analysis type strain gauge means as claimed in claim 4, it is characterized in that: adopt S-codes coding techniques to be by carrying out Hadamard transform to s-matrix, then noise decrease is carried out by superposition, improve signal to noise ratio (S/N ratio), s-matrix is a unipolarity matrix, be made up of 1 and 0, by adopting the exponent number of suitable s-matrix, after data processing end decodes the data that collect, recycle wavelet transformation technique carry out denoising, the to-noise ratio of raising system and then improve measuring accuracy and shorten the Measuring Time of system.