CN103698049A - Brillouin-scattering-based distributed measurement system and method - Google Patents
Brillouin-scattering-based distributed measurement system and method Download PDFInfo
- Publication number
- CN103698049A CN103698049A CN201310699063.6A CN201310699063A CN103698049A CN 103698049 A CN103698049 A CN 103698049A CN 201310699063 A CN201310699063 A CN 201310699063A CN 103698049 A CN103698049 A CN 103698049A
- Authority
- CN
- China
- Prior art keywords
- light
- laser
- ofdm
- optical fiber
- brillouin
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
Images
Landscapes
- Optical Transform (AREA)
Abstract
The invention discloses a Brillouin-scattering-based distributed measurement system, which comprises a first laser unit capable of splitting a laser beam into locally-oscillated light and pump light, a second laser unit capable of modulating laser into an orthogonal frequency division multiplexing light signal which can be used as detection light, a non-coaxial multi-core optical fiber and an optical fiber sensing unit, wherein one end of the non-coaxial multi-core optical fiber is used for receiving the pump light from the first laser unit, and the other end of the non-coaxial multi-core optical fiber is used for receiving the orthogonal frequency division multiplexing light signal; the optical fiber sensing unit is connected with the first and second laser units respectively. According to the Brillouin-scattering-based distributed measurement system, the non-coaxial multi-core optical fiber is used as a sensing optical fiber instead of a single-mode single-core optical fiber, so that the cross sensitivity of temperature and stress can be distinguished; the orthogonal frequency division multiplexing light signal is used as the detection light in the system instead of single-beam laser, so that the scanning speed can be increased, a plurality of frequency points can be scanned at one time, and detection response is quickened. The invention also provides a Brillouin-scattering-based distributed measurement method.
Description
Technical field
The present invention relates to technical field of optical fiber sensing, particularly relate to a kind of Distributed Measurement System and method based on Brillouin scattering.
Background technology
In electric system, cable, wind power equipment etc. is exposed in air for a long time, is easily subject to the impact that external force and external environment change.As strong wind, earthquake and ice damage etc. will make equipment generation deformation, produce sag, thereby cause producing ess-strain, equipment intensity declines, and causes line interruption fault.And stress on equipment impact can not visualize out, once stress accumulation is to a certain extent, cause equipment work to interrupt, can have a strong impact on the safety of the defeated power supply of electric system.On the other hand, in electric system, high temperature, fire are also the Common Accidents that affects safe operation of power system, so the quality of on-line temperature monitoring is very important to safe operation of power system equally.Therefore, monitor in time and grasp equipment ess-strain and temperature variations, and finding fault in time and take preventive measure effectively, most important to improving reliability and the security of electric system.
Brillouin scattering is that light wave and sound wave interact while propagating in optical fiber and the light scattering process that produces, between Brillouin scattering and incident light, there is certain frequency difference, between this frequency difference and temperature and strain, there is good linear relationship, simultaneously with power and the proportional relation of temperature.Optical fiber, as sensor information, has little, lightweight, the anti-electromagnetic interference (EMI) of volume and is easy to the advantages such as networking.By the Brillouin's frequency spectrum in measuring optical fiber, can realize the distributed sensing of temperature and strain in environment, the distributed sensing technology application based on optical fiber Brillouin scattering and giving birth to.
But, because the Brillouin shift while in optical fiber is strained and the impact of temperature, only by single Brillouin shift, cannot tell this frequency displacement is to cause by strain or by temperature, the practical occasion of this sensing technology is greatly limited, this phenomenon, is called " cross sensitivity " problem of Brillouin scattering Fibre Optical Sensor.
In order to address this problem, multiple solution has been proposed.For example, by the Brillouin spectrum of research large effective area non-zero dispersion displacement optical fiber and the relation of strain and temperature, thus the scheme of the solution Brillouin scattering Fibre Optical Sensor cross sensitivity problem proposing.In addition, also proposed to adopt the method for temperature compensation to solve cross sensitivity problem.But, the use of large effective area non-zero scattering optical fiber, system cost increases, and cannot merge with the optical cable of having laid, and it is long to detect the response time, and measuring accuracy is not high.Adopt temperature compensation act, measuring accuracy is not high, detects the response time long.
Summary of the invention
Based on this, being necessary, for the problem that the response time is long, measuring accuracy is not high, provides a kind of Distributed Measurement System and method based on Brillouin scattering.
A Distributed Measurement System based on Brillouin scattering, comprising:
Can by laser beam splitter, be the first laser cell of local oscillator light and pump light;
Laser Modulation can be become can be used as the second laser cell of the OFDM light signal of surveying light;
Non-coaxial multi-barrel optical fiber, one end receives the pump light of described the first laser cell, and the other end receives described OFDM light signal;
Can obtain the Fibre Optical Sensor unit of described non-coaxial multi-barrel fiber core Brillouin shift, be connected respectively with described the first laser cell with the second laser cell, described local oscillator light and detection light are all inputted described Fibre Optical Sensor unit.
Therein in an embodiment, described the first laser cell comprises pump laser, by the first photo-coupler of laser beam splitter, the first electrooptic modulator, the first fiber amplifier, the optical circulator that carry out the modulation of pulse or random series, described pump laser is connected with described the first coupling mechanism, the a branch of input optical fibre sensing unit of laser of described pump laser output, another Shu Yici is by the first electrooptic modulator, the first fiber amplifier and the described non-coaxial multi-barrel optical fiber of optical circulator input, and described optical circulator is connected with described Fibre Optical Sensor unit.
Therein in an embodiment, described optical circulator comprises the first port, the second port and the 3rd port, described the first fiber amplifier is connected with described optical circulator by the first port, described non-coaxial multi-barrel optical fiber one end is connected with described the second port, and described Fibre Optical Sensor unit is connected with described optical circulator by the 3rd port.
In an embodiment, described the first laser cell also comprises optical filter therein, and one end of described optical filter is connected with described optical circulator, and the other end is connected with described Fibre Optical Sensor unit.
Therein in an embodiment, described the second laser cell comprises the second electrooptic modulator, the second fiber amplifier of surveying light laser, the frequency division multiplexing light signal that Laser Modulation can be orthogonal, and the laser of described detection light laser output is inputted non-coaxial multi-barrel optical fiber by the second electrooptic modulator, the second fiber amplifier successively.
Therein in an embodiment, described the second electrooptic modulator comprises OFDM optical signal generator, digital to analog converter, driver and electro-optic modulation arrangement, described OFDM optical signal generator, digital to analog converter, driver are connected successively with electro-optic modulation arrangement, described detection light laser is connected with described electro-optic modulation arrangement, and described the second fiber amplifier is connected with described electro-optic modulation arrangement.
Therein in an embodiment, described Fibre Optical Sensor unit comprises photoelectricity receiving detection device, analog to digital converter, channel estimating apparatus and master control display device, described photoelectricity receiving detection device is connected with the second laser cell with described the first laser cell respectively, described analog to digital converter is connected with described photoelectricity receiving detection device, described channel estimating apparatus is connected with described analog to digital converter, and described master control display device is connected with the first laser cell and is connected with described channel estimating apparatus.
Therein in an embodiment, described photoelectricity receiving detection device comprises the second photo-coupler and photoelectric detector, described the second photo-coupler is connected with the second laser cell with the first laser cell respectively, described photoelectric detector is connected with described the second photo-coupler, and described analog to digital converter is connected with described photoelectric detector.
A distributed measurement method based on Brillouin scattering, comprises the following steps:
Lay non-coaxial multi-barrel optical fiber;
Produce local oscillator light, pump light and can be used as the OFDM light signal of surveying light, modulated pumping light and can be used as the OFDM light signal of surveying light, respectively input pumping light and can be used as survey light OFDM light signal in described non-coaxial multi-barrel optical fiber two ends;
Receive and detect described local oscillator light and the OFDM light signal that carries described non-coaxial multi-barrel optical fiber generation Brillouin scattering light signal;
The OFDM light signal detecting is carried out to modulation /demodulation, draw the brillouin gain spectrum of described non-each fibre core of coaxial multi-barrel optical fiber, and determine the Brillouin shift of each fibre core;
The Brillouin shift causing by temperature and STRESS VARIATION is determined temperature and stress value.
Therein in an embodiment, described the OFDM light signal detecting is carried out to modulation /demodulation, draws the brillouin gain spectrum of described non-each fibre core of coaxial multi-barrel optical fiber, and determine the step of the Brillouin shift of each fibre core, specifically comprise the following steps:
Detected OFDM light signal is carried out to analog to digital conversion;
OFDM electric signal is gone here and there and changed;
The OFDM electric signal of going here and there and changing is removed to Cyclic Prefix;
To going the OFDM electric signal of Cyclic Prefix to carry out fast Fourier transform;
The OFDM electric signal that fast Fourier is changed carries out channel estimating, and draws the Brillouin shift of fibre core.
Above-mentioned Distributed Measurement System and method based on Brillouin scattering, adopt non-coaxial multi-barrel optical fiber as sensor fibre, receive and sensed light signal, light signal comprises local oscillator light and carries the OFDM Detecting light of the light signal of described non-coaxial multi-barrel optical fiber generation Brillouin scattering, then detected light signal is carried out to modulation /demodulation, draw the brillouin gain spectrum of described non-each fibre core of coaxial multi-barrel optical fiber, and the Brillouin shift of definite each fibre core, the Brillouin shift causing by temperature and STRESS VARIATION is determined temperature and stress value.
So, adopt non-coaxial multi-barrel optical fiber to replace single mode single-core fiber as sensor fibre, can distinguish temperature and stress cross sensitivity problem.Adopt OFDM light signal to replace single beam laser as the detection light in system, can greatly increase sweep velocity, the disposable scanning that completes a plurality of frequencies, has improved the detection response time.Employing through the OFDM light signal of ovennodulation as surveying light, through OFDM demodulation, draw the Brillouin shift of non-each fibre core of coaxial multi-barrel optical fiber, reduced system-computed complexity, simplify the averaging process in traditional approach, reduced detection time.In addition, OFDM optical signal transmission can be grown Distance Transmission, transmits precision high, has improved measuring accuracy.
Accompanying drawing explanation
Fig. 1 is the structural representation of the Distributed Measurement System based on Brillouin scattering of an embodiment;
Fig. 2 is the structural representation of the Distributed Measurement System based on Brillouin scattering of another embodiment;
Fig. 3 is the structural representation of the second electrooptic modulator of the Distributed Measurement System based on Brillouin scattering of an embodiment;
Fig. 4 is the schematic flow sheet of the distributed measurement method based on Brillouin scattering of an embodiment;
Fig. 5 is the distributed measurement method OFDM electric signal modulation /demodulation schematic flow sheet based on Brillouin scattering of an embodiment.
Embodiment
For the ease of understanding the present invention, below with reference to relevant drawings, the present invention is described more fully.In accompanying drawing, provided preferred embodiment of the present invention.But the present invention can realize in many different forms, be not limited to embodiment described herein.On the contrary, providing the object of these embodiment is to make to the understanding of disclosure of the present invention more thoroughly comprehensively.
It should be noted that, when element is called as " being fixed on " another element, can directly can there is element placed in the middle in it on another element or also.When an element is considered to " connection " another element, it can be directly connected to another element or may have centering elements simultaneously.Term as used herein " vertical ", " level ", " left side ", " right side " and similar statement are just for illustrative purposes.
Unless otherwise defined, all technology of using are herein identical with the implication that belongs to the common understanding of those skilled in the art of the present invention with scientific terminology.The term using in instructions of the present invention herein, just in order to describe the object of specific embodiment, is not intended to be restriction the present invention.Term as used herein " and/or " comprise one or more relevant Listed Items arbitrarily with all combinations.
As shown in Figure 1, a Distributed Measurement System based on Brillouin scattering, comprise laser can be divided into two bundles the first laser cell 110, Laser Modulation can be become to the second laser cell 120, the non-coaxial multi-barrel optical fiber 130 can be used as the OFDM light signal of surveying light and the Fibre Optical Sensor unit 140 that can obtain non-coaxial multi-barrel optical fiber 130 fibre core Brillouin shifts.The first laser cell 110 can be divided into laser two bundles, and a branch of is local oscillator light, and another bundle is pump light, and non-coaxial multi-barrel optical fiber 130 one end receive the pump light of the first laser cell 110, and the other end receives and can be used as the OFDM light signal of surveying light.The first laser cell 110 is all connected with Fibre Optical Sensor unit 140 with the second laser cell 120, local oscillator light and the equal input optical fibre sensing unit 140 of detection light.
In the present embodiment, adopt non-coaxial multi-barrel optical fiber 130 as sensor fibre, non-coaxial multi-barrel optical fiber 130 is a kind of shared surrounding layers, contains many fibre cores, and every fibre core has again the optical fiber of the inner cladding of oneself.Non-coaxial multi-barrel optical fiber 130 can improve the integration density of stranding, also can reduce construction cost simultaneously.
Because non-coaxial multi-barrel optical fiber 130 fibre core intervals are large, there is not mutually optically-coupled phenomenon, during temperature influence, the Brillouin shift of each fibre core changes identical, and each fibre core position is different, the Brillouin shift while being subject to stress influence changes different.Therefore, can tell Brillouin shift is by temperature or because STRESS VARIATION causes, thereby has solved the cross sensitivity problem of Brillouin scattering sensing.
The first laser cell 110 can be divided into laser two bundles, a branch of local oscillator light that can be used as, and another bundle can be used as pump light.In an embodiment, the first laser cell 110 can comprise pump laser 112, the first photo-coupler 114, the first electrooptic modulator 116, the first fiber amplifier 118 and optical circulator 119 therein.The laser of pump laser 112 transmittings can be used as pump light source, the first photo-coupler 114 can be divided into laser two bundles, the first electrooptic modulator 116 can carry out pulse or random series modulation to pump light, the first 118 pairs of fiber amplifiers pump light amplifies, optical circulator 119 1 ports are connected with non-coaxial multi-barrel optical fiber 130, and another port is connected with Fibre Optical Sensor unit 140.
Wherein, the laser of pump laser 112 outputs is divided into two bundles through the first coupling mechanism 114, a branch of first fiber amplifier 118 of inputting after the first electrooptic modulator 116 pulses or random series modulation as pump light amplifies, thereby enter optical circulator 119 again and be input to non-coaxial multi-barrel optical fiber 130 generation Brillouin scatterings, another beam of laser is as local oscillator light input optical fibre sensing unit 140.
The first photo-coupler 114 is ordinary optic fibre coupling mechanism, is understandable that, in other embodiments, the coupling ratio of the first photo-coupler 114 can be selected according to the needs of practical laser condition and output power, as long as realize the object of system stability work.Pump laser 112 can be end-face pump solid laser, can be also side pumped solid laser device, as long as realize low-power consumption, dependable performance, life-span length, the measured object of output light quality.In the present embodiment, pump laser 112 adopts distributed feedback laser (Distributed Feedback Laser, DFB).The first fiber amplifier 118 is mixed ear amplifier (Erbium-doped Optical Fiber Amplifier, EDFA) for can be.
The second laser cell 120 can become can be used as the OFDM light signal of surveying light by Laser Modulation.
Therein in an embodiment, the second laser cell 120 comprises surveys light laser 122, the second electrooptic modulator 124, the second fiber amplifier 126, surveys 122 outputs of optical signals detecting laser rear by the second electrooptic modulator 124, non-coaxial multi-barrel optical fiber 130 other ends of the second fiber amplifier 126 input.
Surveying light laser 122 compares and has certain frequency difference with the pump laser 112 of the first laser cell 110, as coherent source, the Brillouin shift that the non-coaxial multi-barrel optical fiber of common quartz produces during without strain at normal temperature is about 11GHz, therefore in the present embodiment, frequency difference is 11GHz, when temperature and strain variation, according to the relation of Brillouin shift and temperature and strain, can draw the change information of temperature and strain.
The second electrooptic modulator 124 can will produce OFDM (Orthogonal Frequency Division Multiplexing, OFDM) simulating signal, and carry out OFDM modulation with the laser of surveying light laser 122 outputs, by Laser Modulation, it is OFDM light signal, and through the other end of the non-coaxial multi-barrel optical fiber 130 of the second fiber amplifier 126 input, experience brillouin gain.The second fiber amplifier 126 can be mixes ear amplifier.It should be noted that, OFDM is a kind of multi-carrier modulation technology, and it transmits different information symbols on the subcarrier of a plurality of quadratures, and as 4-qam symbol, frequency resolution is subcarrier spacing.
In the present embodiment, the second electrooptic modulator 124 can adopt Mach-Zeng Deer modulator (Mach-Zehnder Modulator, MZM), MZM modulator is divided into by input light two branch roads that signal that two-way is equal enters respectively modulator, the material that these two light branch roads adopt is electric light material, and the electric signal size that its refractive index applies with outside changes.Because the variations in refractive index of light branch road can cause the variation of signal phase, when two tributary signal modulator output terminals combine again, the light signal of cooperation is by the interference signal that is an intensity size variation, be equivalent to the variation of electric signal to convert to the variation of light signal, realized the modulation of light intensity.
So, by OFDM simulating signal, be OFDM light signal with surveying optical modulation, and finally input non-coaxial multi-barrel optical fiber 130 experience brillouin gains.Adopt OFDM light signal as the detection light in system, can greatly increase sweep velocity, the disposable scanning that completes a plurality of frequencies, reduces detection time.In addition, the interference that adopts OFDM technology can effectively resist signal waveform, is applicable to the high speed data transfer in multi-path environment and fading channel, and the combined coding by each subcarrier has very strong anti-fading ability, applicable to long-distance distributed optical fiber sensing.
Be understandable that, the second electrooptic modulator 124 also can adopt other electrooptic modulators, as long as realize the object of OFDM optical signal modulation.The second fiber amplifier 126 also can adopt other fiber amplifier, as long as realize OFDM optical signal amplification.
Fibre Optical Sensor unit 140 can obtain the Brillouin shift of non-coaxial multi-barrel optical fiber 130 fibre cores, is connected respectively local oscillator light and the equal input optical fibre sensing unit 140 of detection light with the first laser cell 110 with the second laser cell 120.
Therein in an embodiment, Fibre Optical Sensor unit 140 can comprise photoelectricity receiving detection device 142, analog to digital converter 144, channel estimating apparatus 146 and master control display device 148, photoelectricity receiving detection device 142 is connected with the second laser cell 120 with the first laser cell 110 respectively, analog to digital converter 144 is connected with photoelectric detection system, channel estimating apparatus 146 is connected with analog to digital converter 144, master control display device 148 is connected with channel estimating apparatus 146, is also connected with the first laser cell 110.
Refer to Fig. 2, therein in an embodiment, photoelectricity receiving detection device 142 comprises the second photo-coupler 1422 and photoelectric detector 1424, the second photo-coupler 1422 is connected with the second laser cell 120 with the first laser cell 110 respectively, and photoelectric detector 1424 is connected with the second photo-coupler 1422.The first laser cell 110 laser are divided into two bundles, as a branch of input second photo-coupler 1422, the second laser cells 120 of local oscillator light, by optical circulator 119, are connected with the second photo-coupler 1422, and analog to digital converter 144 is connected with photoelectric detector 1424.
The first laser cell 110 pump lights are inputted non-coaxial multi-barrel optical fiber 130, produce Brillouin scattering, when pump light equates with the detection frequency difference of light and the Brillouin shift in certain region in optical fiber, this region will produce Brillouin amplification effect, be brillouin gain, between pump light and detection light, energy occur and shift.OFDM light signal is inputted non-coaxial multi-barrel optical fiber 130 experience brillouin gains as surveying light, because brillouin scattering signal is contrary with pump direction, OFDM light signal carries brillouin scattering signal and at the second photo-coupler 1422, is coupled into photoelectric detector 1424 through optical circulator 119 and local oscillator light.
Wherein, the analog-to-digital OFDM light signal of 146 pairs of processes of channel estimating apparatus has carried out OFDM demodulation, so that the data processing of brillouin scattering signal.It should be noted that, demodulation is the process of message recovery from carry the modulated signal of message, and transmitting terminal is modulated carrier wave by the message that institute's tendency to develop is sent, and produces the signal that carries this message, and the message that receiving end recovers to transmit just can be used.Above-mentioned detection method adopts direct Detection Method, by OFDM light signal, carries brillouin scattering signal, then light signal is converted to electric signal, and demodulator circuit detects information, and direct-detection algorithm reduces cost greatly.
Be understandable that, photoelectricity receiving detection device 142 can be also coherent receiver 1426, the OFDM light signal of local oscillator light input coherent receiver 1426, the second laser cells 120 of the first laser cell 110 carries brillouin scattering signal through optical circulator 119 input coherent receivers 1426.So, as long as realize the OFDM light signal that receives and detect local oscillator light and carry brillouin scattering signal, and the object of OFDM light signal being carried out to demodulation.Above-mentioned detection scheme adopts coherent detection scheme, utilize the coherence of light that the entrained information signal of light carrier is detected and processed, compare with direct-detection, relevant detection more easily obtains large signal to noise ratio (S/N ratio), and recoverable signal kinds is many, and frequency selectivity is better, be more suitable for dense wavelength division multiplexing system, therefore, in transmitting procedure, error is little, has improved degree of accuracy.In addition, coherent receiver 1426 highly sensitive, has increased the unrepeatered transmission distance of light signal, thereby has increased measuring distance.
Analog to digital converter 144 is connected with photoelectric detection system 142, and channel estimating apparatus 146 is connected with analog to digital converter 144, and master control display device 148 is connected with channel estimating apparatus 146, is also connected with the first laser cell 110.So, analog to digital converter 144 can be converted to OFDM light signal OFDM electric signal, thereby the brillouin gain that channel estimating apparatus 146 obtains each fibre core by channel estimation technique is composed, thereby master control display device 148 draws the Brillouin shift of each fibre core through data processing, draw temperature and stress value.Wherein, master control display device 148 is also connected with the first electrooptic modulator 116, thereby controls pulse or the random series modulation of the first electrooptic modulator 116.
The above-mentioned Distributed Measurement System based on Brillouin scattering, comprise first laser cell 110 that laser beam splitter can be become to local oscillator light and pump light, Laser Modulation can be become can be used as the second laser cell 120 of the OFDM light signal of surveying light, one end receives the first laser cell 110 pump lights, the other end receives the non-coaxial multi-barrel optical fiber 130 of OFDM light signal, and the Fibre Optical Sensor unit 140 that can obtain non-coaxial multi-barrel optical fiber 130 fibre core Brillouin shifts.Fibre Optical Sensor unit 140 is connected with the second laser cell 120 with the first laser cell 110 respectively, local oscillator light and the equal input optical fibre sensing unit 140 of detection light.
So, the first laser cell 110 is local oscillator light and pump light by laser beam splitter, the second laser cell 120 is by the Laser Modulation frequency division multiplexing light signal that is orthogonal, the pump light that the first laser cell 110 beam splitting go out is inputted one end of non-coaxial multi-barrel optical fiber 130, produce Brillouin scattering, the second laser cell 120 is inputted OFDM light signal the other end of non-coaxial multi-barrel optical fiber 130, and experiences brillouin gain.Due to the direction of brillouin scattering signal and the opposite direction of pump light, OFDM light signal carries brillouin scattering signal input optical fibre sensing unit 140.The local oscillator light of the first laser cell 110 beam splitting is input optical fibre sensing unit 140 also, detection detection by Fibre Optical Sensor unit 140, OFDM demodulation, channel estimating etc., finally obtain the brillouin gain spectrum of each fibre core, find the Brillouin shift that obtains each fibre core after peak value.The Brillouin shift causing according to temperature variation is identical in each fibre core, and the Brillouin shift that STRESS VARIATION causes is different temperature and the stress values distinguished in each fibre core, thereby has solved cross sensitivity problem.In addition, adopt Distributed Measurement System applicable to the measurement of long distance.
Adopt non-coaxial multi-barrel optical fiber 130 to replace single mode single-core fiber as sensor fibre, can distinguish temperature and stress cross sensitivity problem.Non-coaxial multi-barrel optical fiber 130 also can improve the integration density of stranding, also can reduce construction cost simultaneously.Adopt OFDM light signal to replace single beam laser as the detection light in system, can greatly increase sweep velocity, the disposable scanning that completes a plurality of frequencies, has improved the detection response time, has also improved measurement dynamic range.In addition, the interference that adopts OFDM technology can effectively resist signal waveform, be applicable to the high speed data transfer in multi-path environment and fading channel, combined coding by each subcarrier has very strong anti-fading ability, applicable to long-distance distributed optical fiber sensing, large leap ahead measuring distance, also improved measuring accuracy.
Refer to Fig. 1, in an embodiment, the first laser cell 110 also comprises optical filter 115 therein, and one end of optical filter 115 is connected with optical circulator 119, and the other end is connected with Fibre Optical Sensor unit 140.Signal in generation, conversion, transmitting procedure due to the existence of environment and interference deformity, to such an extent as to signal and entrained information thereof are by noise, thereby form interference (inter-carrier interference between OFDM subcarrier, ICI), so, wave filter can improve the transmission precision of OFDM greatly, thereby has guaranteed accuracy of detection.In addition, wave filter, also by the end face reflection light filtering in the Ruili scattering in signal and system, has improved the accuracy of detection of system.
Refer to Fig. 3, therein in an embodiment, the second electrooptic modulator 124 comprises OFDM optical signal generator 1242, digital to analog converter 1244, driver 1246 and electro-optic modulation arrangement 1248, OFDM optical signal generator 1242, digital to analog converter 1244, driver 1246 and electro-optic modulation arrangement 1248 are connected successively, survey light laser 122 and be connected with electro-optic modulation arrangement 1248, the second fiber amplifier 126 is connected with electro-optic modulation arrangement 1248.Orthogonal multiplex optical signal generator output OFDM signal, digital to analog converter 1244 converts ofdm signal to simulating signal, driver 1246 drives electro-optic modulation arrangement 1248 by OFDM simulating signal and surveys the Laser Modulation that light laser 122 exports and becomes OFDM light signal, then inputs the second fiber amplifier 126 and be amplified into non-coaxial multi-barrel optical fiber 130.So, to realize orthogonal frequency division multiplexi, transmit, improved sweep velocity, reduced detection time.
As shown in Figure 4, a kind of distributed measurement method based on Brillouin scattering, comprises the following steps:
Step S110, lays non-coaxial multi-barrel optical fiber 130;
Step S120, produce local oscillator light, pump light and can be used as the OFDM light signal of surveying light, modulated pumping light and can be used as the OFDM light signal of surveying light, respectively input pumping light and can be used as survey light OFDM light signal in described non-coaxial multi-barrel optical fiber 130 two ends;
Step S130, receives and detects described local oscillator light and carry the OFDM light signal that Brillouin scattering light signal occurs described non-coaxial multi-barrel optical fiber 130;
Step S140, carries out modulation /demodulation to the OFDM light signal detecting, and draws the brillouin gain spectrum of described non-coaxial multi-barrel optical fiber 130 each fibre core, and determines the Brillouin shift of each fibre core;
Step S150, the Brillouin shift causing by temperature and STRESS VARIATION calculates temperature and stress value.
The above-mentioned distributed measurement method based on Brillouin scattering, lay non-coaxial multi-barrel optical fiber 130, produce local oscillator light, pump light and can be used as the OFDM light signal of surveying light, respectively input pumping light and can be used as survey light OFDM light signal in described non-coaxial multi-barrel optical fiber 130 two ends.Receive and detect described local oscillator light and carry the OFDM light signal that Brillouin scattering light signal occurs described non-coaxial multi-barrel optical fiber 130.The OFDM light signal detecting is carried out to modulation /demodulation, draw the brillouin gain spectrum of described non-coaxial multi-barrel optical fiber 130 each fibre core, and determine the Brillouin shift of each fibre core; , then determine temperature and stress value according to the Brillouin shift that temperature and STRESS VARIATION cause.
So, adopt non-coaxial multi-barrel optical fiber 130 to replace single mode single-core fiber as sensor fibre, can distinguish temperature and stress cross sensitivity problem.Non-coaxial multi-barrel optical fiber 130 also can improve the integration density of stranding, also can reduce construction cost simultaneously.Adopt OFDM light signal to replace single beam laser as the detection light in system, can greatly increase sweep velocity, the disposable scanning that completes a plurality of frequencies, has improved the detection response time.
Employing through the OFDM of ovennodulation as surveying light, through OFDM demodulation, draw the Brillouin shift of non-coaxial multi-barrel optical fiber 130 each fibre core, can reduce system-computed complexity, avoid passing through the processes such as electrooptical modulation, Polarization Control, signal averaging, simplify the averaging process in traditional approach, reduced detection time.OFDM optical signal transmission can be grown Distance Transmission, transmits precision high, has improved measuring accuracy.
Refer to Fig. 5, in an embodiment, step S140 carries out modulation /demodulation to the OFDM light signal detecting therein, draws the brillouin gain spectrum of described non-each fibre core of coaxial multi-barrel optical fiber, and the step of the Brillouin shift of definite each fibre core, specifically comprise the following steps:
Step S141, carries out analog to digital conversion to detected OFDM light signal;
Step S142, goes here and there and changes OFDM electric signal;
Step S144, removes Cyclic Prefix to the OFDM electric signal of going here and there and changing;
Step S146, to going the OFDM electric signal of Cyclic Prefix to carry out fast Fourier transform;
Step S148, the OFDM electric signal that fast Fourier is changed carries out channel estimating, and draws the Brillouin shift of fibre core.
So, can calculate fast and accurately the Brillouin shift of each fibre core to the modulation /demodulation of OFDM electric signal, through steps such as OFDM demodulation, analog to digital conversion and channel estimating, can reduce system-computed complexity, simplify the averaging process in traditional approach, reduced detection time.
In an embodiment, the OFDM electric signal that step S148 changes fast Fourier carries out channel estimating and is specially therein:
If it is X that OFDM surveys the symbol on k subcarrier on light signal
k, the symbol on this subcarrier receiving while processing ofdm signal in photoelectricity receiving detection device 142 is Y
k, the signal relative intensity of this subcarrier is
According to relative intensity H
k, the frequency of trying to achieve its peaked subcarrier is Brillouin shift υ
bor υ (T)
b(ε).Then utilize formula:
T＝T
r+[υ
B(T)/υ
B(T
r)-1]/C
rT
ε＝ε
r+[υ
B(ε)/υ
B(ε
r)-1]/C
rε
Can draw temperature value T or stress value ε.T in its Chinese style
r, ε
rfor reference temperature and Reference Stress, C
rT, C
r εfor temperature control coefficient and stress sensitivity coefficient, υ
b(T
r) be reference temperature T
runder Brillouin shift, υ
b(ε
r) be Reference Stress ε
runder Brillouin shift.
So, by can be calculated the Brillouin shift of each fibre core, thereby the distribution of definite temperature and stress realizes Measurement accuracy.
The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (10)
1. the Distributed Measurement System based on Brillouin scattering, is characterized in that, comprising:
Can by laser beam splitter, be the first laser cell of local oscillator light and pump light;
Laser Modulation can be become can be used as the second laser cell of the OFDM light signal of surveying light;
Non-coaxial multi-barrel optical fiber, one end receives the pump light of described the first laser cell, and the other end receives described OFDM light signal;
Can obtain the Fibre Optical Sensor unit of described non-coaxial multi-barrel fiber core Brillouin shift, be connected respectively with described the first laser cell with the second laser cell, described local oscillator light and detection light are all inputted described Fibre Optical Sensor unit.
2. the Distributed Measurement System based on Brillouin scattering according to claim 1, it is characterized in that, described the first laser cell comprises pump laser, by the first photo-coupler of laser beam splitter, carry out the first electrooptic modulator of pulse or random series modulation, the first fiber amplifier, optical circulator, described pump laser is connected with described the first coupling mechanism, the a branch of input optical fibre sensing unit of laser of described pump laser output, another Shu Yici is by the first electrooptic modulator, the first fiber amplifier and the described non-coaxial multi-barrel optical fiber of optical circulator input, described optical circulator is connected with described Fibre Optical Sensor unit.
3. the Distributed Measurement System based on Brillouin scattering according to claim 2, it is characterized in that, described optical circulator comprises the first port, the second port and the 3rd port, described the first fiber amplifier is connected with described optical circulator by the first port, described non-coaxial multi-barrel optical fiber one end is connected with described the second port, and described Fibre Optical Sensor unit is connected with described optical circulator by the 3rd port.
4. the Distributed Measurement System based on Brillouin scattering according to claim 2, it is characterized in that, described the first laser cell also comprises optical filter, and one end of described optical filter is connected with described optical circulator, and the other end is connected with described Fibre Optical Sensor unit.
5. the Distributed Measurement System based on Brillouin scattering according to claim 1, it is characterized in that, described the second laser cell comprises the second electrooptic modulator, the second fiber amplifier of surveying light laser, the frequency division multiplexing light signal that Laser Modulation can be orthogonal, and the laser of described detection light laser output is inputted non-coaxial multi-barrel optical fiber by the second electrooptic modulator, the second fiber amplifier successively.
6. the Distributed Measurement System based on Brillouin scattering according to claim 5, it is characterized in that, described the second electrooptic modulator comprises OFDM optical signal generator, digital to analog converter, driver and electro-optic modulation arrangement, described OFDM optical signal generator, digital to analog converter, driver are connected successively with electro-optic modulation arrangement, described detection light laser is connected with described electro-optic modulation arrangement, and described the second fiber amplifier is connected with described electro-optic modulation arrangement.
7. the Distributed Measurement System based on Brillouin scattering according to claim 1, it is characterized in that, described Fibre Optical Sensor unit comprises photoelectricity receiving detection device, analog to digital converter, channel estimating apparatus and master control display device, described photoelectricity receiving detection device is connected with the second laser cell with described the first laser cell respectively, described analog to digital converter is connected with described photoelectricity receiving detection device, described channel estimating apparatus is connected with described analog to digital converter, and described master control display device is connected with the first laser cell and is connected with described channel estimating apparatus.
8. the Distributed Measurement System based on Brillouin scattering according to claim 7, it is characterized in that, described photoelectricity receiving detection device comprises the second photo-coupler and photoelectric detector, described the second photo-coupler is connected with the second laser cell with the first laser cell respectively, described photoelectric detector is connected with described the second photo-coupler, and described analog to digital converter is connected with described photoelectric detector.
9. the distributed measurement method based on Brillouin scattering, is characterized in that, comprises the following steps:
Lay non-coaxial multi-barrel optical fiber;
Produce local oscillator light, pump light and can be used as the OFDM light signal of surveying light, modulated pumping light and can be used as the OFDM light signal of surveying light, respectively input pumping light and can be used as survey light OFDM light signal in described non-coaxial multi-barrel optical fiber two ends;
Receive and detect described local oscillator light and the OFDM light signal that carries described non-coaxial multi-barrel optical fiber generation Brillouin scattering light signal;
The OFDM light signal detecting is carried out to modulation /demodulation, draw the brillouin gain spectrum of described non-each fibre core of coaxial multi-barrel optical fiber, and determine the Brillouin shift of each fibre core;
The Brillouin shift causing by temperature and STRESS VARIATION is determined temperature and stress value.
10. the distributed measurement method based on Brillouin scattering according to claim 9, it is characterized in that, described the OFDM light signal detecting is carried out to modulation /demodulation, draw the brillouin gain spectrum of described non-each fibre core of coaxial multi-barrel optical fiber, and the step of the Brillouin shift of definite each fibre core, specifically comprise the following steps:
Detected OFDM light signal is carried out to analog to digital conversion;
OFDM electric signal is gone here and there and changed;
The OFDM electric signal of going here and there and changing is removed to Cyclic Prefix;
To going the OFDM electric signal of Cyclic Prefix to carry out fast Fourier transform;
The OFDM electric signal that fast Fourier is changed carries out channel estimating, and draws the Brillouin shift of fibre core.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310699063.6A CN103698049B (en) | 2013-12-18 | 2013-12-18 | Distributed Measurement System based on Brillouin scattering and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310699063.6A CN103698049B (en) | 2013-12-18 | 2013-12-18 | Distributed Measurement System based on Brillouin scattering and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103698049A true CN103698049A (en) | 2014-04-02 |
| CN103698049B CN103698049B (en) | 2016-09-14 |
Family
ID=50359656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310699063.6A Active CN103698049B (en) | 2013-12-18 | 2013-12-18 | Distributed Measurement System based on Brillouin scattering and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103698049B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105004459A (en) * | 2015-07-22 | 2015-10-28 | 哈尔滨工业大学 | High-sensitivity distributed transverse pressure sensor and method for measuring transverse pressure by utilizing sensor |
| CN105371785A (en) * | 2015-11-13 | 2016-03-02 | 华中科技大学 | Curvature measurement method |
| CN107588873A (en) * | 2017-07-20 | 2018-01-16 | 全球能源互联网研究院 | A kind of fibre-optical sensing device with electromagnetic environment monitor function |
| CN109000157A (en) * | 2018-10-01 | 2018-12-14 | 江苏亨通光纤科技有限公司 | A kind of pipeline on-Line Monitor Device and monitoring method |
| CN110441651A (en) * | 2019-07-25 | 2019-11-12 | 武汉钜风科技有限公司 | A kind of transmission line status detection method and system based on OPGW |
| CN110440841A (en) * | 2019-07-25 | 2019-11-12 | 武汉钜风科技有限公司 | A kind of Brillouin optical time domain analysis instrument |
| CN111051832A (en) * | 2017-05-11 | 2020-04-21 | 费布斯光学公司 | Photoelectric device for optical fiber distributed measurement |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050213869A1 (en) * | 2004-03-26 | 2005-09-29 | Anthony Brown | System and method for resolution enhancement of a distributed sensor |
| CN101485054A (en) * | 2006-07-05 | 2009-07-15 | 索雷克核研究中心 | Optical apparatus comprising a pump-light-guiding fiber |
| CN102221421A (en) * | 2011-03-29 | 2011-10-19 | 宁波诺驰光电科技发展有限公司 | Distributed optical fiber sensor for temperature and strain measurement and measuring method |
| CN103115695A (en) * | 2013-01-17 | 2013-05-22 | 广东电网公司电力调度控制中心 | Double-sideband distributed type optical fiber sensing system parameter measuring device |
| CN103175558A (en) * | 2013-01-17 | 2013-06-26 | 广东电网公司电力调度控制中心 | Parameter measuring device of distributed optical fiber sensing system |
| CN203672517U (en) * | 2013-12-18 | 2014-06-25 | 中国能源建设集团广东省电力设计研究院 | Brillouin scattering based distributed measurement system |
-
2013
- 2013-12-18 CN CN201310699063.6A patent/CN103698049B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050213869A1 (en) * | 2004-03-26 | 2005-09-29 | Anthony Brown | System and method for resolution enhancement of a distributed sensor |
| CN101485054A (en) * | 2006-07-05 | 2009-07-15 | 索雷克核研究中心 | Optical apparatus comprising a pump-light-guiding fiber |
| CN102221421A (en) * | 2011-03-29 | 2011-10-19 | 宁波诺驰光电科技发展有限公司 | Distributed optical fiber sensor for temperature and strain measurement and measuring method |
| CN103115695A (en) * | 2013-01-17 | 2013-05-22 | 广东电网公司电力调度控制中心 | Double-sideband distributed type optical fiber sensing system parameter measuring device |
| CN103175558A (en) * | 2013-01-17 | 2013-06-26 | 广东电网公司电力调度控制中心 | Parameter measuring device of distributed optical fiber sensing system |
| CN203672517U (en) * | 2013-12-18 | 2014-06-25 | 中国能源建设集团广东省电力设计研究院 | Brillouin scattering based distributed measurement system |
Non-Patent Citations (2)
| Title |
|---|
| 杨利敏等: "双芯光纤的制作及应用研究", 《光电技术应用》 * |
| 邹毅: "可调谐双芯光纤及其在光纤光栅传感与滤波器中应用的研究", 《中国优秀硕士学位论文全文数据库（信息科技辑）》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105004459A (en) * | 2015-07-22 | 2015-10-28 | 哈尔滨工业大学 | High-sensitivity distributed transverse pressure sensor and method for measuring transverse pressure by utilizing sensor |
| CN105371785A (en) * | 2015-11-13 | 2016-03-02 | 华中科技大学 | Curvature measurement method |
| CN105371785B (en) * | 2015-11-13 | 2018-04-17 | 华中科技大学 | A kind of curvature measurement method |
| CN111051832A (en) * | 2017-05-11 | 2020-04-21 | 费布斯光学公司 | Photoelectric device for optical fiber distributed measurement |
| CN111051832B (en) * | 2017-05-11 | 2021-10-08 | 费布斯光学公司 | Photoelectric device for optical fiber distributed measurement |
| CN107588873A (en) * | 2017-07-20 | 2018-01-16 | 全球能源互联网研究院 | A kind of fibre-optical sensing device with electromagnetic environment monitor function |
| CN107588873B (en) * | 2017-07-20 | 2020-02-07 | 全球能源互联网研究院 | Optical fiber sensing device with electromagnetic environment monitoring function |
| CN109000157A (en) * | 2018-10-01 | 2018-12-14 | 江苏亨通光纤科技有限公司 | A kind of pipeline on-Line Monitor Device and monitoring method |
| CN109000157B (en) * | 2018-10-01 | 2024-03-29 | 江苏亨通光纤科技有限公司 | Online monitoring device and method for pipeline |
| CN110441651A (en) * | 2019-07-25 | 2019-11-12 | 武汉钜风科技有限公司 | A kind of transmission line status detection method and system based on OPGW |
| CN110440841A (en) * | 2019-07-25 | 2019-11-12 | 武汉钜风科技有限公司 | A kind of Brillouin optical time domain analysis instrument |
| CN110441651B (en) * | 2019-07-25 | 2021-07-30 | 武汉钜风科技有限公司 | Transmission line state detection method and system based on OPGW |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103698049B (en) | 2016-09-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103698049A (en) | Brillouin-scattering-based distributed measurement system and method | |
| CN107917738B (en) | Distributed optical fiber sensing system capable of simultaneously measuring temperature, strain and vibration | |
| Martins et al. | Real time dynamic strain monitoring of optical links using the backreflection of live PSK data | |
| CN102759371B (en) | COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer | |
| CN106483373B (en) | A kind of electrooptic modulator frequency response measurement method and measuring system | |
| CN103048070B (en) | Stress monitoring method of distributed optical fiber system | |
| CN105634588B (en) | Coherent optical time domain reflectometer based on phase conjugation Shuangzi ripple | |
| CN103115695B (en) | Double-sideband distributed type optical fiber sensing system parameter measuring device | |
| CN104180833A (en) | Optical time domain reflectometer simultaneously sensing temperature and stress | |
| CN103743354B (en) | A kind of dynamic strain measurement method based on Brillouin's phase shift detection and measurement apparatus | |
| CN106768277B (en) | A kind of demodulation method of distributed optical fiber vibration sensing device | |
| CN105004355B (en) | Phi-OTDR reinforcing method based on polarized orthogonal optical pulse pair and device thereof | |
| CN104819770A (en) | Phase-light time domain reflection device and method based on heterodyne detection phase demodulation | |
| CN109297425A (en) | A kind of Brillouin optical time-domain reflectometer of physical random number modulation | |
| Wu et al. | Frequency response enhancement of phase-sensitive OTDR for interrogating weak reflector array by using OFDM and vernier effect | |
| CN105628063A (en) | Brillouin light time domain analysis device and method based on dual-wavelength polarization orthogonal light | |
| CN108917804A (en) | Quick long-distance distributed Brillouin light fiber sensing equipment based on chirp chain | |
| CN103076112A (en) | Parameter-measuring system for single side band distributed optical fiber sensing system | |
| CN115200691A (en) | Few-mode optical fiber distributed acoustic sensing system and signal processing method thereof | |
| CN111829584B (en) | Continuous space synchronous monitoring device for ocean temperature and pressure | |
| Huang et al. | Single-end hybrid Rayleigh Brillouin and Raman distributed fibre-optic sensing system | |
| CN203672517U (en) | Brillouin scattering based distributed measurement system | |
| Huang et al. | Hybrid distributed fiber-optic sensing system by using Rayleigh backscattering lightwave as probe of stimulated Brillouin scattering | |
| CN103616090A (en) | Brillouin distributed type optical fiber sensing temperature measurement system for eliminating optical fiber attenuation | |
| CN110768714B (en) | Polarized light time domain reflectometer based on dual-polarization state time division multiplexing and detection method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C53 | Correction of patent of invention or patent application | ||
| CB02 | Change of applicant information |
Address after: 510663 Luogang District, Guangdong, Guangzhou Science City Fung Road, No. 1, No. Applicant after: Company limited of China Energy Engineering Group Guangdong Electric Power Design Institute Applicant after: Guangdong Grid Company Electric Power Dispatch Control Central Address before: 510663 Luogang District, Guangdong, Guangzhou Science City Fung Road, No. 1, No. Applicant before: Guangdong Electric Power Design Institute of CEEC Applicant before: Guangdong Grid Company Electric Power Dispatch Control Central |
|
| COR | Change of bibliographic data |
Free format text: CORRECT: APPLICANT; FROM: CHINA ENERGY ENGINEERING GROUP GUANGDONG ELECTRIC POWER DESIGN INSTITUTE TO: CHINA ENERGY ENGINEERING GROUP GUANGDONG ELECTRIC POWER DESIGN INSTITUTE CO., LTD. |
|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |