CN110375800B - Sensing device and method based on super-continuum spectrum Brillouin optical time domain analyzer - Google Patents
Sensing device and method based on super-continuum spectrum Brillouin optical time domain analyzer Download PDFInfo
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Abstract
The device comprises a super-continuum spectrum light source, three tunable optical filters, three 1 multiplied by 2 optical fiber couplers, two polarization controllers, two high-speed electro-optical modulators, a microwave signal source, three optical amplifiers, an optical polarization scrambler, an optical isolator, a sensing optical fiber, an optical circulator, a pulse generator, three photoelectric detectors, a data acquisition card and a computer. The invention can enhance the dynamic range of the BOTDA, increase the measurement distance of the optical fiber and improve the spatial resolution of the system; the device adopts opposite detection optical signals, and solves the problems that the power of the traditional BOTDA single-path signal is gradually lost along with the increase of the optical fiber distance, and the detection distance is limited; the invention adopts a super-continuum spectrum light source, and has a wider spectrum range relative to a tunable laser. The tunable laser with adjustable wavelength and variable spatial resolution can be generated by matching with an optical filter. The invention adopts the super-continuum spectrum light source as the pumping light source, solves the problem of limited measuring distance of the narrow-band laser, and enhances the stability of the system.
Description
Technical Field
The invention is applied to the field of distributed optical fiber sensing detection, in particular to a sensing device and a sensing method based on a super-continuum spectrum Brillouin optical time domain analyzer, which can realize high spatial resolution and long-distance continuous measurement of temperature or strain.
Background
The distributed Optical fiber temperature and strain sensing technology based on Brillouin Optical Time Domain Analysis (BOTDA) is a novel sensing technology developed in the last three decades, has the unique advantages that the distribution information of a field to be measured along the whole Optical fiber can be obtained through one-Time measurement, the positioning is accurate, dynamic measurement can be realized, the distance can reach dozens of kilometers or even hundreds of kilometers, and the like, and has wide application prospect in the online monitoring of the health condition of large engineering structures in the industries of electric power, petroleum, water conservancy and the like.
Research based on rayleigh scattering and raman scattering has been mature and gradually put to practical use. The research of the distributed sensing technology based on the brillouin scattering starts late, but the measurement precision, the measurement range and the spatial resolution of the distributed sensing technology based on the brillouin scattering on temperature and strain measurement are higher than those of other sensing technologies, so that the technology is widely focused and researched at present.
Brillouin scattering optical time domain analysis (BOTDA) was first proposed by Horiguchi Tsuneo in 1989, and uses the amplification effect of stimulated Brillouin as the strain sensing mechanism (Journal of Lightwave Technology, 1989, 7(8): 1170-1176.). Horiguchi et al investigators first injected pulsed light and continuous probe light simultaneously at both ends of a 1.2km single mode fiber, respectively, to achieve a spatial resolution of 100m and a temperature fraction of 3 deg.C (Applied Optics, 1990, 29(15): 2219-2222). Bao Xiaoyi et al made significant progress in the study of Brillouin depletion type BOTDA systems (Opt Lett. 1993 Sep 15;18(18): 1561.) with a sensing length of 32 km, a temperature resolution of 1 ℃ and a spatial resolution of 5 m was obtained. Thevenaz et al, the Federal institute of Federal technology, Switzerland, used the BOTDA system to obtain a spatial resolution of 7m in 2008 over a sensing length of 47km (IEEE Sensors Journal 8(7): 1268-. Several companies abroad today have developed in succession commercial BOTDA temperature/strain gauges, such as: smartec of Switzerland DiTSt system manufactured by Omnisens company, the temperature resolution of which is 1 ℃ and the strain resolution of which is 20 mu epsilon; the Foresight series of systems, OZ, Canada, achieve a spatial resolution of 10cm over a distance of 50 km.
The light source used by the traditional BOTDA system is a narrow-linewidth laser source, the pump light is continuous light, and the probe light is pulse light. In the gain type BOTDA, the frequency of pump light is higher than that of detection pulse light, the frequency difference of two paths of signals is about Brillouin frequency shift, stimulated Brillouin scattering occurs in the optical fiber along with the increase of the power of the pump light, and the energy of the pump light is transferred to the detection pulse light through an acoustic wave field. Because the stimulated Brillouin scattering intensity in the optical fiber is related to the frequency shift difference of two paths of signals, when the frequency shift of the pump light and the probe light is equal to the Brillouin frequency phase shift, the transfer energy of the two paths of light is the largest, the power value of each frequency point is recorded by changing the frequency shift difference of the pump light and the probe light to obtain the peak power, the Brillouin gain spectrum of each point of the optical fiber to be detected can be obtained by performing Lorentz fitting, the peak power corresponds to the Brillouin frequency shift, and the distributed optical fiber sensing and the structure monitoring can be realized through the Brillouin frequency shift of each position of the optical fiber and the linear relation between the Brillouin frequency shift and strain or temperature. However, the BOTDA system uses the optical pulse signal as the detection signal to realize the positioning of the optical fiber temperature or strain, if the pulse width of the detection pulse is increased, the pulse optical power is increased, which is beneficial to improving the measurement distance, but the spatial resolution is reduced, so that the spatial resolution of the BOTDA system is about 1 meter.
Recently, chaotic laser signals are used for replacing narrow-linewidth laser sources, and the chaotic laser signals have the characteristic of a single correlation peak correlation function and high spatial resolution unrelated to distance, so that long-distance distributed optical fiber sensing can be realized. The invention patent (201610305960.8) in China adopts chaotic laser signals, but the chaotic laser signals generally adopt light injection and light feedback to introduce periodic signals, so that the low coherent state of the chaotic signals is damaged, and the spatial resolution of the system is reduced.
The invention patent (CN 103115632 a) uses a multi-wavelength light source as a light source of the brillouin optical time domain analyzer, and by increasing the number of wavelengths of the probe light and the pump light, the total optical power entering the optical fiber can be increased without causing stimulated brillouin scattering, and the signal-to-noise ratio of the system can be improved. However, the system needs to be matched with and adjust a plurality of parameters, and the system structure and the realization process are complex, time-consuming and high in cost.
The invention adopts a low coherence state and a wide spectrum to output a high-power super-continuum spectrum, the optical power incident into the measured optical fiber is lower than the stimulated Brillouin threshold value due to various nonlinear effects in the optical fiber, and the super-wide spectrum means that the optical fiber has an ultrahigh stimulated Brillouin scattering threshold value. The BOTDA system needs ultra-long distance sensing, the power of detection pulse light and continuous pump light must be improved, the super-continuum spectrum utilizes the advantages of the BOTDA system to solve the problem of low power, in addition, the signal-to-noise ratio (SNR) of the BOTDA system is another important factor, the signal-to-noise ratio of the system can be greatly improved by using a super-continuum spectrum light source, the dynamic range of the system can be determined, and the measurement accuracy of the system can be influenced.
Disclosure of Invention
The invention provides a distributed Optical fiber sensing device and a method for realizing Optical fiber temperature or strain positioning based on Brillouin Optical Time Domain Analysis (BOTDA). The invention combines the temperature and strain effect of optical fiber Brillouin scattering, and can realize ultra-long distance measurement for accurately positioning temperature or strain.
The invention is realized by adopting the following technical scheme: a sensing device based on a supercontinuum Brillouin optical time domain analyzer comprises: the device comprises a supercontinuum light source, a first tunable optical filter, a 1 x 2 first optical fiber coupler, a first polarization controller, a microwave signal source, a first high-speed electro-optical modulator, a first optical amplifier, an optical polarization scrambler, an optical isolator, a sensing optical fiber, a second polarization controller, a second high-speed electro-optical modulator, a pulse generator, a 1 x 2 second optical fiber coupler, a second optical amplifier, an optical circulator, a third optical amplifier, a 1 x 2 third optical fiber coupler, a second tunable optical filter, a third tunable optical filter, a first photoelectric detector, a second photoelectric detector, a third photoelectric detector, a data acquisition card and a computer.
The emergent end of the super-continuum spectrum light source is connected with the incident end of the first tunable optical filter; the emergent end of the first tunable optical filter is connected with the incident end of the 1 multiplied by 2 first optical fiber coupler through a single-mode optical fiber jumper;
the first emergent end of the 1 multiplied by 2 first optical fiber coupler is connected with the incident end of a first polarization controller through a single-mode optical fiber jumper, and the emergent end of the first polarization controller is connected with the incident end of a first high-speed electro-optic modulator; the emergent end of the first high-speed electro-optical modulator is connected with the incident end of the first optical amplifier through a single-mode optical fiber jumper; the signal output end of the microwave signal source is connected with the radio frequency input end of the first high-speed electro-optical modulator through a high-frequency coaxial cable; the incident end of the first optical amplifier is connected with the incident end of the optical polarization scrambler through a single-mode optical fiber jumper; the exit end of the optical polarization scrambler is connected with the entrance end of the optical isolator through a single-mode optical fiber jumper; the emergent end of the optical isolator is connected with the incident end of the sensing optical fiber through a single-mode optical fiber jumper; the emergent end of the sensing optical fiber is connected with the reflecting end of the optical circulator through a single-mode optical fiber jumper;
the second emergent end of the 1 multiplied by 2 first optical fiber coupler is connected with the incident end of the second polarization controller through a single-mode optical fiber jumper; the emergent end of the second polarization controller is connected with the incident end of the second high-speed electro-optic modulator through a single-mode optical fiber jumper; the emergent end of the second high-speed electro-optical modulator is connected with the incident end of the 1 multiplied by 2 second optical fiber coupler through a single-mode optical fiber jumper; the signal output end of the pulse generator is connected with the radio frequency input end of the second high-speed electro-optic modulator through a high-frequency coaxial cable;
the first emergent end of the 1 multiplied by 2 second optical fiber coupler is connected with the incident end of the second optical amplifier through a single-mode optical fiber jumper; the exit end of the second optical amplifier is connected with the entrance end of the optical circulator through a single-mode optical fiber jumper; the exit end of the optical circulator is connected with the incident end of the third optical amplifier through a single-mode optical fiber jumper; the emergent end of the third optical amplifier is connected with the incident end of the 1 multiplied by 2 third optical fiber coupler;
the first emergent end of the 1 multiplied by 2 third optical fiber coupler is connected with the incident end of the second tunable optical filter; the exit end of the second tunable optical filter is connected with the incident end of the second photoelectric detector through a single-mode optical fiber jumper; the emergent end of the second photoelectric detector is connected with the first signal input end of the data acquisition card through a single-mode optical fiber jumper;
the second emergent end of the 1 multiplied by 2 third optical fiber coupler is connected with the incident end of the third tunable optical filter; the exit end of the third tunable optical filter is connected with the incident end of the third photoelectric detector through a single-mode optical fiber jumper; the emergent end of the third photoelectric detector is connected with the second signal input end of the data acquisition card through a single-mode optical fiber jumper;
the second emergent end of the 1 multiplied by 2 second optical fiber coupler is connected with the incident end of the first photoelectric detector through a single-mode optical fiber jumper; the emergent end of the first photoelectric detector is connected with the third signal input end of the data acquisition card through a single-mode optical fiber jumper; the signal output end of the data acquisition card is connected with the signal input end of the computer.
A sensing method based on a supercontinuum Brillouin optical time domain analyzer is realized by the following steps:
the laser signal emitted by the supercontinuum light source selects a spectrum with a proper bandwidth through a first tunable optical filter, and then the first tunable optical filter is divided into two paths through a 1 multiplied by 2 first optical fiber coupler: the first path of super-continuum spectrum optical signal is used as a detection optical signal, and the second path of super-continuum spectrum optical signal is used as a pumping optical signal; the detection optical signal firstly selects a proper optical polarization state through a first polarization controller, laser passes through a high-speed electro-optic modulator and is modulated by a sinusoidal signal output by a microwave signal source, so that the frequency shift of a detection optical sideband signal is close to Brillouin frequency shift, and then the detection optical signal enters a sensing optical fiber after being amplified, polarized and isolated by a first optical amplifier, an optical polarization scrambler and an optical isolator in sequence; the pumping light signal firstly passes through a second polarization controller to select a proper light polarization state, then passes through a high-speed electro-optical modulator, is modulated by a pulse signal output by a pulse generator, and then enters a sensing optical fiber after being split, amplified and looped by a 1 x 2 second optical fiber coupler, a second optical amplifier and an optical circulator;
after the pump light after pulse modulation is split by the 1 × 2 second optical fiber coupler, one beam of the pump light enters the sensing optical fiber as the pump light, just as in the step 1, the other beam of the pump light is converted into an electric signal through the first photoelectric detector as the reference light, and then the electric signal is input into the computer after being collected by the data collection card;
the detection optical sideband signal and the pump optical signal modulated by the pulse meet at a certain position in the sensing optical fiber, the frequency shift of the detection optical sideband signal is close to Brillouin frequency shift by adjusting the frequency of the detection optical sideband signal, and the detection optical sideband signal is amplified when the optical fiber generates stimulated Brillouin scattering; when the frequency is exactly equal to the Brillouin frequency shift quantity, the detection optical power amplitude signal is maximum; when the optical fiber generates stimulated Brillouin scattering, backward Rayleigh scattering optical signals can be generated by the pump light; after the pump light which is backward Rayleigh scattered is output from the emergent end of the optical circulator, the position signal of the optical fiber temperature or strain can be determined by calculating the correlation function and Fourier transform between the pump light backward Rayleigh scattered signal and the reference signal; after the pumping light and the amplified detection light sideband signals are output from the emergent end of the optical circulator, the signals are amplified by a third optical amplifier and enter a 1 multiplied by 2 third optical fiber coupler to be divided into two paths, and one path is filtered by a second tunable optical filter to obtain backward Rayleigh scattered light signals; the backward Rayleigh scattering pump light filtered out by the second tunable optical filter is converted into an electric signal by the second photoelectric detector and then input into the data acquisition card, and the other path of detection optical sideband signal filtered out by the third tunable optical filter is converted into an electric signal by the third photoelectric detector and then input into the data acquisition card; inputting the collected data into a computer, and obtaining strain and temperature information of different positions on the sensing optical fiber by calculating a detection optical sideband signal and a reference signal; and the Brillouin gain spectrum of the optical fiber can be determined by calculating the relationship between the frequency of the detection optical sideband signal and the modulation frequency, and the strain and temperature information of different positions on the sensing optical fiber can be obtained.
Compared with the existing distributed optical fiber sensing system, the sensing device and the sensing method based on the supercontinuum Brillouin optical time domain analyzer have the following advantages that:
compared with the prior art, the invention adopts the supercontinuum laser as a detection signal, has an ultra-wideband spectrum, and obtains the position of the signal through the correlation operation processing of the signal light and the local reference light; the reliability and the stability of the sensor are effectively improved, the spatial resolution is adjustable, and the spatial resolution can reach millimeter level.
The invention can break through the problem of limited sensing distance caused by insufficient output power of the traditional light source, the traditional light source needs to use an EDFA optical amplifier to amplify the power of the light source, and the device is easy to introduce ASE noise, so that the signal-to-noise ratio is reduced, and certain uncertain factors are added to the system; the super-continuum spectrum light source has high output power, and the problem of measuring super-long distance in the distributed optical fiber sensing technology of the existing Brillouin optical time domain system can be effectively solved.
Thirdly, the system is a super-continuum spectrum Brillouin optical time domain analyzer, and the signal-to-noise ratio of the system is mainly determined by the power of the detection pulse light and the continuous pumping light; on the premise that the stimulated Brillouin scattering does not occur, the larger the power of the two paths is, the better the signal-to-noise ratio is. The signal-to-noise ratio is an important parameter of the BOTDA, and determines the dynamic range and measurement accuracy of the system. In addition, the increase of the average measurement times also improves the signal-to-noise ratio of the system to a certain extent, but the signal-to-noise ratio basically has no space for improving the signal-to-noise ratio after the certain average times, and the more the system measurement times are, the more the time is consumed, so the supercontinuum has certain advantages in the two aspects of improving the signal-to-noise ratio of the system.
Drawings
FIG. 1 is a schematic diagram of the structure of the apparatus of the present invention.
In the figure, a 1-supercontinuum light source, a 2-first tunable optical filter, a 3-1 x 2 first optical fiber coupler, a 4-first polarization controller, a 5-microwave signal source, a 6-first high-speed electro-optical modulator, a 7-first optical amplifier, an 8-optical polarization scrambler, a 9-optical isolator, a 10-sensing optical fiber, an 11-second polarization controller, a 12-second high-speed electro-optical modulator, a 13-pulse generator, a 14-1 x 2 second optical fiber coupler, a 15-second optical amplifier, a 16-optical circulator, a 17-third optical amplifier, an 18-1 x 2 third optical fiber coupler, a 19-second tunable optical filter, a 20-third tunable optical filter, a 21-first photoelectric detector, a 22-second photoelectric detector, 23-a third photoelectric detector, 24-a data acquisition card and 25-a computer.
Detailed Description
A sensing device based on a supercontinuum Brillouin optical time domain analyzer comprises a supercontinuum light source 1, a first tunable optical filter 2, a 1 x 2 first optical fiber coupler 3, a first polarization controller 4, a microwave signal source 5, a first high-speed electro-optic modulator 6, a first optical amplifier 7, an optical deflector 8, an optical isolator 9, a sensing optical fiber 10, a second polarization controller 11, a second high-speed electro-optic modulator 12, a pulse generator 13, a 1 x 2 second optical fiber coupler 14, a second optical amplifier 15, an optical circulator 16, a third optical amplifier 17, a 1 x 2 third optical fiber coupler 18, a second tunable optical filter 19, a third tunable optical filter 20, a first photoelectric detector 21, a second photoelectric detector 22, a third photoelectric detector 23, a data acquisition card 24 and a computer 25.
The emergent end of the super-continuum spectrum light source 1 is connected with the incident end of the first tunable optical filter 2; the emergent end of the first tunable optical filter 2 is connected with the incident end of the 1 multiplied by 2 first optical fiber coupler 3 through a single mode optical fiber jumper;
the first emergent end of the 1 multiplied by 2 first optical fiber coupler 3 is connected with the incident end of the first polarization controller 4 through a single-mode optical fiber jumper, and the emergent end of the first polarization controller 4 is connected with the incident end of the first high-speed electro-optical modulator 6; the emergent end of the first high-speed electro-optical modulator 6 is connected with the incident end of the first optical amplifier 7 through a single-mode optical fiber jumper; the signal output end of the microwave signal source 5 is connected with the radio frequency input end of the first high-speed electro-optical modulator 6 through a high-frequency coaxial cable; the incident end of the first optical amplifier 7 is connected with the incident end of the optical polarization scrambler 8 through a single-mode optical fiber jumper; the emergent end of the optical polarization scrambler 8 is connected with the incident end of the optical isolator 9 through a single-mode optical fiber jumper; the emergent end of the optical isolator 9 is connected with the incident end of the sensing optical fiber 10 through a single-mode optical fiber jumper; the emergent end of the sensing optical fiber 10 is connected with the reflecting end of the optical circulator 16 through a single-mode optical fiber jumper;
the second emergent end of the 1 × 2 first optical fiber coupler 3 is connected with the incident end of the second polarization controller 11 through a single-mode optical fiber jumper; the emergent end of the second polarization controller 11 is connected with the incident end of the second high-speed electro-optical modulator 12 through a single-mode optical fiber jumper; the emergent end of the second high-speed electro-optical modulator 12 is connected with the incident end of the 1 × 2 second optical fiber coupler 14 through a single-mode optical fiber jumper; the signal output end of the pulse generator 13 is connected with the radio frequency input end of the second high-speed electro-optical modulator 12 through a high-frequency coaxial cable;
a first emergent end of the 1 × 2 second optical fiber coupler 14 is connected with an incident end of the second optical amplifier 15 through a single-mode optical fiber jumper; the exit end of the second optical amplifier 15 is connected with the entrance end of the optical circulator 16 through a single-mode optical fiber jumper; the exit end of the optical circulator 16 is connected with the entrance end of the third optical amplifier 17 through a single-mode optical fiber jumper; the emergent end of the third optical amplifier 17 is connected with the incident end of the 1 multiplied by 2 third optical fiber coupler 18;
the first emergent end of the 1 multiplied by 2 third optical fiber coupler 18 is connected with the incident end of the second tunable optical filter 19; the exit end of the second tunable optical filter 19 is connected with the incident end of the second photodetector 22 through a single-mode optical fiber jumper; the emergent end of the second photoelectric detector 22 is connected with the first signal input end of the data acquisition card 24 through a single-mode optical fiber jumper;
the second emergent end of the 1 × 2 third optical fiber coupler 18 is connected with the incident end of the third tunable optical filter 20; the exit end of the third tunable optical filter 20 is connected with the incident end of the third photodetector 23 through a single-mode optical fiber jumper; the emergent end of the third photoelectric detector 23 is connected with the second signal input end of the data acquisition card 24 through a single-mode optical fiber jumper;
the second emergent end of the 1 × 2 second optical fiber coupler 14 is connected with the incident end of the first photodetector 21 through a single-mode optical fiber jumper; the emergent end of the first photoelectric detector 21 is connected with the third signal input end of the data acquisition card 24 through a single-mode optical fiber jumper; the signal output end of the data acquisition card 24 is connected with the signal input end of the computer 25.
A sensing method based on a supercontinuum Brillouin optical time domain analyzer is realized by the following steps:
the laser signal emitted by the supercontinuum light source 1 selects a spectrum with a proper bandwidth through the first tunable optical filter 2, and then the first tunable optical filter 2 is divided into two paths through the 1 multiplied by 2 first optical fiber coupler 3: the first path of super-continuum spectrum optical signal is used as a detection optical signal, and the second path of super-continuum spectrum optical signal is used as a pumping optical signal; the detection light signal firstly selects a proper light polarization state through the first polarization controller 4, the laser passes through the high-speed electro-optic modulator 6 and is modulated by a sinusoidal signal output by the microwave signal source 5, so that the frequency shift of the detection light sideband signal is close to Brillouin frequency shift, and then the detection light signal enters the sensing optical fiber 10 after being amplified, disturbed and isolated through the first optical amplifier 7, the optical deflector 8 and the optical isolator 9 in sequence; the pumping light signal firstly passes through the second polarization controller 11 to select a proper light polarization state, then passes through the high-speed electro-optical modulator 12, is modulated by the pulse signal output by the pulse generator 13, and then enters the sensing optical fiber 10 after being split, amplified and looped by the 1 x 2 second optical fiber coupler 14, the second optical amplifier 15 and the optical circulator 16;
after the pump light after pulse modulation is split by the 1 × 2 second optical fiber coupler 14, one beam enters the sensing optical fiber 10 as the pump light, just as in step 1, the other beam is converted into an electric signal by the first photoelectric detector 21 as the reference light, and then is input into the computer 25 after being collected by the data collection card 24;
the detection optical sideband signal and the pump optical signal modulated by the pulse meet at a certain position in the sensing optical fiber 10, the frequency shift of the detection optical sideband signal is close to Brillouin frequency shift by adjusting the frequency of the detection optical sideband signal, and the detection optical sideband signal is amplified when the optical fiber generates stimulated Brillouin scattering; when the frequency is exactly equal to the Brillouin frequency shift quantity, the detection optical power amplitude signal is maximum; when the optical fiber generates stimulated Brillouin scattering, backward Rayleigh scattering optical signals can be generated by the pump light; after the pump light which is backward rayleigh scattered is output from the emergent end of the optical circulator 16, the position signal of the optical fiber temperature or strain can be determined by calculating the correlation function and the Fourier transform between the pump light backward rayleigh scattered signal and the reference signal again; after the pumping light and the amplified detection light sideband signal are output from the emergent end of the optical circulator 16, the pumping light and the amplified detection light sideband signal are amplified by a third optical amplifier 17 and enter a 1 multiplied by 2 third optical fiber coupler 18 to be divided into two paths, and one path is filtered out backward Rayleigh scattering optical signals by a second tunable optical filter 19; the backward Rayleigh scattering pump light filtered out by the second tunable optical filter 19 is converted into an electric signal by the second photoelectric detector 22 and then input into the data acquisition card 24, and the other detection optical sideband signal filtered out by the third tunable optical filter 20 is converted into an electric signal by the third photoelectric detector 23 and then input into the data acquisition card 24; inputting the collected data into a computer 25, and calculating a detection light sideband signal and a reference signal to obtain strain and temperature information of different positions on the sensing optical fiber 10; and the brillouin gain spectrum of the optical fiber can be determined by calculating the relationship between the frequency of the detection optical sideband signal and the modulation frequency, and strain and temperature information of different positions on the sensing optical fiber 10 can be obtained.
In specific implementation, the light source comprises a super-continuum spectrum light source 1 consisting of 1455nm quasi-continuous wave Raman fiber laser and 16km true wave fiber, the true wave fiber has zero dispersion wavelength at 1440nm, and the dispersion slope is 0.045ps/nm2And/km. The pump light can realize the generation of modulation instability and a supercontinuum light source by the combination of modulation instability, stimulated Raman scattering and four-wave mixing in the anomalous dispersion state of the true-wave optical fiber. When the pump power reaches 0.95W, a spectral component extending to the 1550nm region is generated. When the pump power is increased to 1.48W, the resulting spectral bandwidth is maximized, i.e., 141 in the 10dB rangenm, and the spectral bandwidth can reach 29.328 THz; since the spectral width is tunable, Lc = c/(n Δ f), Lc is the coherence length of the laser signal, which is related to the spectral width, and the spatial resolution is equal to the coherence length of the laser signal. Wherein c = 3x108m/s is the speed of light, n = 1.5 is the refractive index of the fiber, and Δ f is the spectral width of the spectrum. When the laser with the bandwidth of 63.7GHz is filtered and output by the second tunable optical filter 2, the spatial resolution can reach 1 mm. The supercontinuum light source is selected to have a center wavelength of 1550nm by means of a first tunable optical filter 2. The coupling ratio of the 1 × 2 first fiber coupler 3 and the 1 × 2 second fiber coupler 14 is 50: 50. The first high-speed electro-optical modulator 6 and the second high-speed electro-optical modulator 12 are intensity modulators of LN81S-FC type. The microwave signal source 5 adopts a Model-SNP1012-520-01 type microwave signal source. The pulse generator 13 is an HP 8015A type pulse signal generator. The first optical amplifier 7, the second optical amplifier 15 and the third optical amplifier 17 are erbium-doped fiber amplifiers or semiconductor optical amplifiers. The second tunable optical filter 18 employs an XTM-50 type wavelength and bandwidth tunable optical filter. The sensing fiber adopts G.652 series single-mode fiber or G.655 single-mode fiber, and the length of the sensing fiber is 300 km.
Compared with the traditional Brillouin optical time domain analysis technology, the method can enhance the dynamic range of the BOTDA, increase the measurement distance of the optical fiber and improve the spatial resolution of the system; the device adopts opposite detection optical signals, and solves the problems that the power of the traditional BOTDA single-path signal is gradually lost along with the increase of the optical fiber distance, and the detection distance is limited; the invention adopts a super-continuum spectrum light source, and has a wider spectrum range relative to a tunable laser. The tunable laser with adjustable wavelength and variable spatial resolution can be generated by matching with an optical filter. The invention adopts the supercontinuum light source as the pumping light source, solves the problem of limited measuring distance of the narrow-band laser and enhances the stability of the system.
Claims (2)
1. A sensing device based on a supercontinuum Brillouin optical time domain analyzer is characterized in that: the device comprises a supercontinuum light source (1), a first tunable optical filter (2), a 1 x 2 first optical fiber coupler (3), a first polarization controller (4), a microwave signal source (5), a first high-speed electro-optic modulator (6), a first optical amplifier (7), an optical deflector (8), an optical isolator (9), a sensing optical fiber (10), a second polarization controller (11), a second high-speed electro-optic modulator (12), a pulse generator (13), a 1 x 2 second optical fiber coupler (14), a second optical amplifier (15), an optical circulator (16), a third optical amplifier (17), a 1 x 2 third optical fiber coupler (18), a second tunable optical filter (19), a third tunable optical filter (20), a first photoelectric detector (21), a second photoelectric detector (22), a third photoelectric detector (23), a data acquisition card (24), A computer (25);
the emergent end of the super-continuum spectrum light source (1) is connected with the incident end of the first tunable optical filter (2); the emergent end of the first tunable optical filter (2) is connected with the incident end of the 1 multiplied by 2 first optical fiber coupler (3) through a single-mode optical fiber jumper;
the first emergent end of the 1 multiplied by 2 first optical fiber coupler (3) is connected with the incident end of a first polarization controller (4) through a single-mode optical fiber jumper, and the emergent end of the first polarization controller (4) is connected with the incident end of a first high-speed electro-optical modulator (6); the emergent end of the first high-speed electro-optical modulator (6) is connected with the incident end of the first optical amplifier (7) through a single-mode optical fiber jumper; the signal output end of the microwave signal source (5) is connected with the radio frequency input end of the first high-speed electro-optical modulator (6) through a high-frequency coaxial cable; the incident end of the first optical amplifier (7) is connected with the incident end of the optical polarization scrambler (8) through a single-mode optical fiber jumper; the emergent end of the optical polarization scrambler (8) is connected with the incident end of the optical isolator (9) through a single-mode optical fiber jumper; the emergent end of the optical isolator (9) is connected with the incident end of the sensing optical fiber (10) through a single-mode optical fiber jumper; the emergent end of the sensing optical fiber (10) is connected with the reflecting end of the optical circulator (16) through a single-mode optical fiber jumper;
the second emergent end of the 1 multiplied by 2 first optical fiber coupler (3) is connected with the incident end of the second polarization controller (11) through a single-mode optical fiber jumper; the emergent end of the second polarization controller (11) is connected with the incident end of the second high-speed electro-optic modulator (12) through a single-mode optical fiber jumper; the emergent end of the second high-speed electro-optical modulator (12) is connected with the incident end of the 1 multiplied by 2 second optical fiber coupler (14) through a single-mode optical fiber jumper; the signal output end of the pulse generator (13) is connected with the radio frequency input end of the second high-speed electro-optical modulator (12) through a high-frequency coaxial cable;
the first emergent end of the 1 multiplied by 2 second optical fiber coupler (14) is connected with the incident end of the second optical amplifier (15) through a single-mode optical fiber jumper; the emergent end of the second optical amplifier (15) is connected with the incident end of the optical circulator (16) through a single-mode optical fiber jumper; the emergent end of the optical circulator (16) is connected with the incident end of a third optical amplifier (17) through a single-mode optical fiber jumper; the emergent end of the third optical amplifier (17) is connected with the incident end of a 1 multiplied by 2 third optical fiber coupler (18);
the first emergent end of the 1 multiplied by 2 third optical fiber coupler (18) is connected with the incident end of the second tunable optical filter (19); the exit end of the second tunable optical filter (19) is connected with the incident end of a second photoelectric detector (22) through a single-mode optical fiber jumper; the emergent end of the second photoelectric detector (22) is connected with the first signal input end of the data acquisition card (24) through a single-mode optical fiber jumper;
the second emergent end of the 1 multiplied by 2 third optical fiber coupler (18) is connected with the incident end of a third tunable optical filter (20); the exit end of the third tunable optical filter (20) is connected with the incident end of a third photoelectric detector (23) through a single-mode optical fiber jumper; the emergent end of the third photoelectric detector (23) is connected with the second signal input end of the data acquisition card (24) through a single-mode optical fiber jumper;
the second emergent end of the 1 multiplied by 2 second optical fiber coupler (14) is connected with the incident end of the first photoelectric detector (21) through a single-mode optical fiber jumper; the emergent end of the first photoelectric detector (21) is connected with the third signal input end of the data acquisition card (24) through a single-mode optical fiber jumper; the signal output end of the data acquisition card (24) is connected with the signal input end of the computer (25).
2. A sensing method based on a supercontinuum brillouin optical time domain analyzer, which is implemented in the sensing apparatus based on the supercontinuum brillouin optical time domain analyzer according to claim 1, characterized in that: the method is realized by adopting the following steps:
a laser signal emitted by a supercontinuum light source (1) selects a spectrum with a proper bandwidth through a first tunable optical filter (2), and then the first tunable optical filter (2) is divided into two paths through a 1 multiplied by 2 first optical fiber coupler (3): the first path of super-continuum spectrum optical signal is used as a detection optical signal, and the second path of super-continuum spectrum optical signal is used as a pumping optical signal; the detection light signal firstly passes through a first polarization controller (4) to select a proper light polarization state, laser passes through a first high-speed electro-optic modulator (6) and is modulated by a sinusoidal signal output by a microwave signal source (5), so that the frequency shift of a detection light sideband signal is close to Brillouin frequency shift, and then the detection light signal enters a sensing optical fiber (10) after being amplified, polarized and isolated by a first optical amplifier (7), an optical polarization scrambler (8) and an optical isolator (9) in sequence; the pumping light signal firstly passes through a second polarization controller (11) to select a proper light polarization state, then passes through a high-speed electro-optical modulator (12), is modulated by a pulse signal output by a pulse generator (13), and then enters a sensing optical fiber (10) after being split, amplified and looped by a 1 x 2 second optical fiber coupler (14), a second optical amplifier (15) and an optical circulator (16);
after the pump light after pulse modulation is split by the 1 multiplied by 2 second optical fiber coupler (14), one beam as the pump light enters the sensing optical fiber (10), as described in step 1, the other beam as the reference light is converted into an electric signal by the first photoelectric detector (21), and then the electric signal is input into the computer (25) after being collected by the data acquisition card (24);
the detection optical sideband signal and the pump optical signal modulated by the pulse meet at a certain position in the sensing optical fiber (10), the frequency shift of the detection optical sideband signal is close to Brillouin frequency shift by adjusting the frequency of the detection optical sideband signal, and the detection optical sideband signal is amplified when the optical fiber generates stimulated Brillouin scattering; when the frequency is exactly equal to the Brillouin frequency shift quantity, the detection optical power amplitude signal is maximum; when the optical fiber generates stimulated Brillouin scattering, backward Rayleigh scattering optical signals can be generated by the pump light; after the pump light which is backward Rayleigh scattered is output from the emergent end of the optical circulator (16), the position signal of the optical fiber temperature or strain can be determined through the correlation function calculation and Fourier transform between the pump light backward Rayleigh scattered signal and the reference signal; after pump light and amplified detection light sideband signals are output from the emergent end of the optical circulator (16), the signals are amplified by a third optical amplifier (17) and enter a 1 multiplied by 2 third optical fiber coupler (18) to be divided into two paths, and one path is filtered by a second tunable optical filter (19) to obtain backward Rayleigh scattered light signals; the backward Rayleigh scattering pump light filtered by the second tunable optical filter (19) is converted into an electric signal by the second photoelectric detector (22) and then is input into the data acquisition card (24), and the other path of detection light side band signal filtered by the third tunable optical filter (20) is converted into an electric signal by the third photoelectric detector (23) and then is input into the data acquisition card (24); inputting the collected data into a computer (25), and obtaining strain and temperature information of different positions on the sensing optical fiber (10) by calculating a detection optical sideband signal and a reference signal; and the Brillouin gain spectrum of the optical fiber can be determined by calculating the relationship between the frequency of the detection optical sideband signal and the modulation frequency, and strain and temperature information of different positions on the sensing optical fiber (10) can be obtained.
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| CN114061637B (en) * | 2020-07-29 | 2024-03-22 | 哈尔滨工业大学 | Laser detection signal splicing and expansion method based on optical fiber Rayleigh scattering spectrum correlation |
| CN112284430B (en) * | 2020-10-23 | 2022-04-08 | 天津大学 | Multiphase flow multi-parameter optical fiber detection device based on light-carried microwave interference |
| CN114136363B (en) * | 2021-10-22 | 2023-11-07 | 陕西电器研究所 | BOTDA-based distributed optical fiber strain and temperature measuring device |
| CN114088123B (en) * | 2022-01-19 | 2022-04-12 | 苏州光格科技股份有限公司 | Sensing device and sensing method based on Brillouin optical time domain analysis |
| CN114441475B (en) * | 2022-01-27 | 2023-09-26 | 天津大学 | Myocardial damage marker sensing device and measuring method based on WGM optical fiber probe |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101762290A (en) * | 2010-02-03 | 2010-06-30 | 电子科技大学 | Distributed Raman amplification-based Brillouin optical time domain analysis system |
| CN102322806A (en) * | 2011-08-01 | 2012-01-18 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer relevant to chaotic laser |
| CN202182702U (en) * | 2011-08-01 | 2012-04-04 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer using chaotic laser method |
| CN105784195A (en) * | 2016-05-10 | 2016-07-20 | 太原理工大学 | Single-end chaotic Brillouin optical time-domain analysis distributed fiber sensing device and method |
| CN105928634A (en) * | 2016-04-21 | 2016-09-07 | 太原理工大学 | High-voltage cable temperature measuring device and method for single-ended Brillouin optical coherence domain analysis |
| CN109297425A (en) * | 2018-08-23 | 2019-02-01 | 太原理工大学 | A kind of Brillouin optical time-domain reflectometer of physical random number modulation |
| US10294146B2 (en) * | 2016-08-31 | 2019-05-21 | Corning Incorporated | Single mode optical fibers with Brillouin frequency-shift management |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2783023A1 (en) * | 2011-07-12 | 2013-01-12 | University Of New Brunswick | Method and apparatus for central frequency estimation |
-
2019
- 2019-06-03 CN CN201910477901.2A patent/CN110375800B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101762290A (en) * | 2010-02-03 | 2010-06-30 | 电子科技大学 | Distributed Raman amplification-based Brillouin optical time domain analysis system |
| CN102322806A (en) * | 2011-08-01 | 2012-01-18 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer relevant to chaotic laser |
| CN202182702U (en) * | 2011-08-01 | 2012-04-04 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer using chaotic laser method |
| CN105928634A (en) * | 2016-04-21 | 2016-09-07 | 太原理工大学 | High-voltage cable temperature measuring device and method for single-ended Brillouin optical coherence domain analysis |
| CN105784195A (en) * | 2016-05-10 | 2016-07-20 | 太原理工大学 | Single-end chaotic Brillouin optical time-domain analysis distributed fiber sensing device and method |
| US10294146B2 (en) * | 2016-08-31 | 2019-05-21 | Corning Incorporated | Single mode optical fibers with Brillouin frequency-shift management |
| CN109297425A (en) * | 2018-08-23 | 2019-02-01 | 太原理工大学 | A kind of Brillouin optical time-domain reflectometer of physical random number modulation |
Non-Patent Citations (3)
| Title |
|---|
| Cyclic coding for Brillouin optical time-domain analyzers using probe dithering;HARITZ IRIBAS等;《OPTICS EXPRESS》;20170417;第25卷(第8期);全文 * |
| Enhancement of the Dynamic Range in Slope-Assisted Coherent Brillouin Optical Time-Domain Analysis Sensors;Jon Mari˜nelarena等;《IEEE Photonics Journal》;20170630;第9卷(第3期);全文 * |
| 一种利用布里渊增益谱边带解调提高布里渊光时域反射系统测温精度的方法;刘瑞霞等;《物理学报》;20161231;第65卷(第24期);全文 * |
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