CN108507662A - Optical fiber distributed sensing method and device based on multi-wavelength double-optical pulse - Google Patents
Optical fiber distributed sensing method and device based on multi-wavelength double-optical pulse Download PDFInfo
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- CN108507662A CN108507662A CN201810210817.XA CN201810210817A CN108507662A CN 108507662 A CN108507662 A CN 108507662A CN 201810210817 A CN201810210817 A CN 201810210817A CN 108507662 A CN108507662 A CN 108507662A
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- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000013307 optical fiber Substances 0.000 title abstract description 24
- 230000003287 optical effect Effects 0.000 claims abstract description 38
- 239000000835 fiber Substances 0.000 claims description 37
- 230000015572 biosynthetic process Effects 0.000 claims description 12
- 210000001367 artery Anatomy 0.000 claims description 7
- 210000003462 vein Anatomy 0.000 claims description 7
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 238000004080 punching Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 15
- 238000000253 optical time-domain reflectometry Methods 0.000 abstract description 15
- 238000005516 engineering process Methods 0.000 abstract description 13
- 238000005562 fading Methods 0.000 abstract description 7
- 238000005259 measurement Methods 0.000 abstract description 7
- 230000001427 coherent effect Effects 0.000 description 12
- 230000010287 polarization Effects 0.000 description 10
- 230000007423 decrease Effects 0.000 description 6
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- 238000009826 distribution Methods 0.000 description 3
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
- G01D5/35309—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer
- G01D5/35319—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer using other multiple wave interferometer
Abstract
The invention discloses an optical fiber distributed sensing method and device based on multi-wavelength double-optical pulse, wherein the method comprises the following steps: s1, generating multi-wavelength double-light pulses, and injecting the multi-wavelength double-light pulses into a sensing optical fiber, wherein each pulse in the multi-wavelength double-light pulses comprises a plurality of wavelength components; s2, obtaining Rayleigh optical signals in the sensing optical fibers and interference light intensity of a sensing channel corresponding to the Rayleigh optical signals; and S3, calculating the interference light intensity to acquire the phase information of the Rayleigh optical signal so as to acquire the information of the signal sensed by the sensing optical fiber. The invention has the advantages of being used for the phi-OTDR technology based on the PGC phase demodulation technology, reducing the influence of Rayleigh optical fiber signal intensity fading on the measurement noise on the premise of not increasing the signal processing workload, eliminating the detection blind area caused by high phase noise and the like.
Description
Technical field
The present invention relates to distributed fiber-optic sensor technology more particularly to a kind of fiber distributions based on multi-wavelength double light pulses
Formula method for sensing and device are particularly suitable for vibration or sound-detection.
Background technology
Phase sensitive optical time domain reflectometer technology (Ф-OTDR) is widely used in the applications such as distributed vibration and sound-detection
Field has major application value.Phase-sensitive optical time domain reflectometer collects light arteries and veins by injecting light pulse to sensor fibre
It is punched in the Rayleigh optical signal that each position of optical fiber generates.The phase that Rayleigh signal is obtained using the Strength Changes of Rayleigh signal is believed
Breath realizes the information of extraneous vibration signal.
In order to obtain the phase information of Rayleigh signal, Yuelan Lu et al. propose the Ф-OTDR based on coherent detection structure
System obtains phase information [Yuelan Lu et al., Distributed of Rayleigh signal using coherent detection technology
vibration sensor based on coherent detection of phase-OTDR,Journal of
Lightwave Technology, 2010].The Pan etc. of Siom of Chinese Academy of Sciences is proposed using heterodyne method, is used
Digital coherent detects, and demodulates phase [Z.Pan et al., Phase-sensitive the OTDR system of Rayleigh scattered signal in real time
Based on digital coherent detection, in Optical Sensors and Biophotonic, 2011
Year].A.Masoudi of University of Southampton et al. proposes that the backscatter signal receiving terminal in traditional Ф-OTDR is added one
Non-equilibrium Mach-Zender interferometers (M-ZI) and 3 × 3 couplers obtain Rayleigh signal using 3 × 3 phase demodulation algorithms
Phase information [A.Masoudi et al., A distributed optical fibre dynamic strain sensor
Based on phase-OTDR, Measurement Science and Technology, 2013].Semiconductor institute, Chinese Academy of Sciences
G.Fang et al. phase generated into carrier wave (PGC) algorithm be applied to Ф-OTDR technique, realize that Rayleigh signal phase obtains
[Gaosheng Fang et al., Phase-Sensitive Optical Time Domain Reflectometer Based on
Phase-Generated Carrier Algorithm, Journal of Lightwave Technology, 2015].
Rayleigh light signal strength is determined by more Rayleigh scattering light result of interference in the covered optical fiber of pulsed light.Due to optical fiber
The distribution of scattering-in point is uneven along optical fiber, and Rayleigh light signal strength fluctuation occurs along optical fiber.There is the light of Rayleigh signal fadeout
Fine position measurement noise is high, seriously affects the accuracy of the position physical quantity sensing.In order to solve interference fading to vibrating sensing
Influence of noise, K.Shimizu et al. use coherent detection technology, in conjunction with the average method of frequency displacement, synchronously change when measuring every time
The frequency for becoming local light and detection light, with inhibit interference fading noise influenced caused by system [K.Shimizu et al.,
Characteristics and reduction of coherent fading noise in Rayleigh
Backscattering measurement for optical fibers and components, Lightwave
Technology Journal of, 1992].H.Izumita et al. utilizes frequency hopping, implements repeatedly to Rayleigh signal flat
, the curve of cyclical fluctuations of detective curve is reduced to 0.05dB [H.Izumita et al., Stochastic amplitude
fluctuation in coherent OTDR and a new technique for its reduction by
Stimulating synchronous optical frequency hopping, Journal of Lightwave
Technology, 2002].Shanghai ray machine institute light institute Zhou Jun et al. grinds the theoretical model of coherent detection type Ф-OTDR
Study carefully, proposes that the mode of incident light phase modulation combination coherent detection inhibits method [Zhou Jun et al., based on multi-frequency of interference fading
The comprehensive Phase Demodulation Method of Optic for differentiating interference fading glitch in Ф-OTDR systems, Chinese laser, 2013].
The above-mentioned method reported for work must be filtered the Reyleith scanttering light of different frequency extraction, and to the Reyleith scanttering light of each frequency
It handles respectively, integrated treatment result obtains interference fading inhibition.This process substantially increases back end signal processing
Workload cannot be satisfied the distributed real-time measurement request of vibration.Meanwhile the above method is only applicable to based on coherent detection
Ф-OTDR technique.Compared to the Ф-OTDR based on PGC Phase Demodulation Method of Optic, based on the Ф-OTDR of coherent detection by light source phase
Position influence of noise is more serious, and the noise for being embodied in vibration detecting is high, this influences particularly bright in long-distance distributed vibrating sensing
It is aobvious.
Invention content
The technical problem to be solved in the present invention is that：For technical problem of the existing technology, the present invention provides one
Distributed fiber-optic sensor method and apparatus of the kind based on multi-wavelength double light pulses, can be used for the Ф-based on PGC Phase Demodulation Method of Optic
OTDR technique reduces under the premise of not increasing signal processing workload since Rayleigh fiber-optic signal strength is to measurement noise
Influence, eliminate the detection blind area caused by high phase place noise.
In order to solve the above technical problems, technical solution proposed by the present invention is：A kind of light based on multi-wavelength double light pulses
Fine distribution type sensing method, includes the following steps：
S1. multi-wavelength double light pulses are generated, and the multi-wavelength double light pulses are injected into sensor fibre, the multi-wavelength is double
Each pulse in light pulse includes multiple wavelength components；
S2. Rayleigh optical signal in the sensor fibre and the corresponding sensing passage of the Rayleigh optical signal are obtained
Interference light intensity；
S3. the interference light intensity is calculated, obtains the phase information of the Rayleigh optical signal, to obtain the biography
The information of photosensitive the sensed signal of fibre.
Further, there is preset phase difference between two pulsed lights in the double light pulses.
Further, the double light pulses are generated by pulsed light by the non-equilibrium interferometer with default arm difference.
Further, the difference power of each wavelength components is less than preset threshold value in the double light pulses.
Further, the specific steps of the step S3 include：According to the signal strength information of the Reyleith scanttering light, by micro-
The phase information for dividing multiplication cross algorithm to obtain Reyleith scanttering light, to obtain the information of the sensed signal of the sensor fibre, institute
The information for stating sensed signal includes amplitude, frequency and phase information；The signal strength information of the Reyleith scanttering light is Reyleith scanttering light
In the superposition of each wavelength components strength information.
A kind of distributed fiber-optic sensor device based on multi-wavelength double light pulses, including multi-wavelength double light pulses generation group
Part, circulator, photodetector, data collector, signal processor and signal generator；
The multi-wavelength double light pulses formation component is for generating multi-wavelength double light pulses, in the multi-wavelength double light pulses
Each pulse include multiple wavelength components；
The circulator is used to the multi-wavelength double light pulses injecting sensor fibre, and receives the double light arteries and veins of the multi-wavelength
It is punched in the Rayleigh optical signal generated in the sensor fibre, and exports the Rayleigh optical signal；
The photodetector is used to detect the interference light intensity of the Rayleigh optical signal of the circulator output；
The interference light intensity that the data collector is used to detect the acquisition photodetector, obtains light
Strong signal；
The signal processor obtains the phase letter of the Rayleigh optical signal for calculating the light intensity signal
Breath, to obtain the information of the sensed signal of the sensor fibre；
The signal generator is used to provide drive for the multi-wavelength double light pulses formation component and the data collector
Dynamic signal and clock sync signal.
Further, the multi-wavelength double light pulses formation component includes：Laser, bundling device, light intensity modulator, double light
Impulse modulation component；
The laser is used to generate the multiwavelength laser with multiple and different wavelength；
The bundling device is used to the multiwavelength laser carrying out space to close beam；
The light intensity modulator is used to modulate the intensity of the multiwavelength laser, generates the multi-wavelength monochromatic light being repeated cyclically
Pulse；
The double light pulses modulation component is for being modulated the multi-wavelength monochromatic light pulse, by the multi-wavelength monochromatic light
Impulse modulation is the multi-wavelength double light pulses with preset phase difference.
Further, the laser includes multiple narrow linewidth lasers.
Further, the double light pulses modulation component includes the first coupler, non-equilibrium interferometer, phase difference modulator
With the second coupler；
First coupler is used for two light of the multi-wavelength monochromatic light impulses injection to the non-equilibrium interferometer
Road；
The phase difference modulator is for being modulated the phase of laser in a light path in the non-equilibrium interferometer；
Second coupler is used to the laser in two light paths carrying out space to close beam.
Further, the signal processor has and is used for：According to the signal strength information of the Reyleith scanttering light, pass through differential
Multiplication cross algorithm obtains the phase information of Reyleith scanttering light, described to obtain the information of the sensed signal of the sensor fibre
The information of sensed signal includes amplitude, frequency and phase information；The signal strength information of the Reyleith scanttering light is in Reyleith scanttering light
The strength information of each wavelength components superposition.
Compared with the prior art, the advantages of the present invention are as follows：
1, the present invention utilizes the incident pulse light polarization correlation and wavelength dependence of Rayleigh signal strength, using multi-wavelength
Optical pulse regime, due to wavelength and polarization state difference, the Rayleigh signal strength that each wavelength components generate in pulsed light will not be in light
Fine same position declines simultaneously, can be reduced under the premise of not increasing signal processing workload since Rayleigh fiber-optic signal is strong
Influence of the degree decline to measurement noise.
2, the present invention can obtain higher Ruili signal strength letter using each wavelength components Rayleigh signal of intensity superposition
It makes an uproar and compares, inhibit to detect noise penalty caused by being declined by Rayleigh light signal strength, elimination detection caused by height detects noise is blind
Area.
Description of the drawings
Fig. 1 is the flow diagram of the specific embodiment of the invention.
Fig. 2 is the structural schematic diagram of the specific embodiment of the invention.
Marginal data：1, multi-wavelength double light pulses formation component；11, laser；12, bundling device；13, light intensity modulator；
14, double light pulses modulation component；141, the first coupler；142, non-equilibrium interferometer；1421, long-armed；1422, galianconism；143、
Phase difference modulator；144, the second coupler；2, circulator；3, photodetector；4, data collector；5, signal processor；
6, signal generator；7, sensor fibre.
Specific implementation mode
Below in conjunction with Figure of description and specific preferred embodiment, the invention will be further described, but not therefore and
It limits the scope of the invention.
As shown in Figure 1, the distributed fiber-optic sensor method based on multi-wavelength double light pulses of the present embodiment, step are：S1.
Multi-wavelength double light pulses are generated, and multi-wavelength double light pulses are injected into sensor fibre, each pulse in multi-wavelength double light pulses
Include multiple wavelength components；S2. the corresponding sensing of Rayleigh optical signal and Rayleigh optical signal obtained in sensor fibre is led to
The interference light intensity in road；S3. interference light intensity is calculated, the phase information of Rayleigh optical signal is obtained, to obtain sensor fibre
The information of sensed signal.
In the present embodiment, there is preset phase difference between two pulsed lights in double light pulses.Double light pulses are by arteries and veins
It washes off and is generated by the non-equilibrium interferometer with default arm difference.The wavelength that each pulse in multi-wavelength double light pulses includes
The number of ingredient is denoted as m, and m is more than or equal to 2.The wavelength of wavelength components is denoted as respectively：λ1, λ2..., λm-1, λm.Each wavelength components
Power is same or equivalent, quite refers to that the difference power of each wavelength components in double light pulses is less than preset threshold value.The double light of multi-wavelength
After impulses injection sensor fibre, Reyleith scanttering light can be generated everywhere in sensor fibre.By obtaining Reyleith scanttering light caused by sensor fibre
Be mutually divided into LChannelThe interference light intensity of the Reyleith scanttering light of position each position and is separated by L in sensor fibreChannelOptical fiber structure between position
At a sensing passage, LChannelFor the length of sensing passage.In the present embodiment, with default arm difference LInterferometerIt is non-equilibrium dry
Interferometer generates multi-wavelength double light pulses, if when using Mach-Zender interferometers, LChannel=LInterferometer；If using
When Michelson interferometers, then LChannel=2LInterferometer。
In the present embodiment, a certain wavelength components λ of the pulse (p=1,2) in multi-wavelength double light pulsesI=1,2 ..., m
The intensity of Rayleigh optical signal the interference light intensity of Rayleigh scattering light everywhere is covered in optical fiber by light pulse, as shown in formula (1)：
In formula (1), IP=1,2For the interference light intensity of Rayleigh scattering light,It is λ for wavelength componentsiK-th of Rayleigh scattering light
Amplitude of the vector, contain the polarization information and amplitude information of the Rayleigh scattering light, ωi、βi,kAnd φi,kIt is expressed as wavelength
Ingredient is λiK-th of Rayleigh scattering light angular frequency, propagation constant and transmission accumulated phase, i refers on light pulse frequency spectrum i-th
Wavelength components, k are k-th of Rayleigh scattering light in pulse, and j is unit imaginary number, and e is the nature truth of a matter.
The Rayleigh signal light intensity of a certain wavelength components of light pulse in a fiber is covered auspicious everywhere in optical fiber by light pulse
The interference light intensity of profit scattering light, therefore Rayleigh signal strength is by the transmission accumulated phase of each Rayleigh scattering light in light pulse
φi,k, amplitude and polarization state determine.
In the present embodiment, the specific steps of step S3 include：According to the signal strength information of Reyleith scanttering light, handed over by differential
The phase information that multiplication algorithm obtains Reyleith scanttering light is pitched, to obtain the information of the sensed signal of sensor fibre, sensed letter
Number information include amplitude, frequency and phase information；The signal strength information of Reyleith scanttering light is each wavelength components superposition in Reyleith scanttering light
Strength information.
In the present embodiment, in sensor fibre after the Rayleigh light output that sensed position generates, by photodetector come
The interference light intensity for obtaining Reyleith scanttering light, the interference light intensity satisfaction for the sensing passage that position z locates in sensor fibre is as shown in formula (2)：
In formula (2), I (z) is the interference light intensity of the sensing passage at the z of position, I1,iTo pass through non-equilibrium interferometer galianconism
The λ of light pulseiIngredient is in optical fiber z+LChannelLocate the intensity of the Reyleith scanttering light generated, I2,iTo pass through the long-armed light arteries and veins of non-equilibrium interferometer
The λ of punchingiThe intensity for the Reyleith scanttering light that ingredient generates at optical fiber z, m are the quantity of wavelength components, and z is location information, LChannelFor sensing
The length in channel, φ0The initial phase difference of Rayleigh optical signal, φ are generated for double light pulsessIt is position in [z, z+LChannel] in section
Optical fiber light phase caused by measured physical quantity changes, as measured signal phase, φcosIt is long-armed by non-equilibrium interferometer
Light pulse in the cosine-modulation phase caused by piezoelectric ceramics.Indicate short by non-equilibrium interferometer
The light pulse of arm is in optical fiber z+LChannelLocate the intensity of the Reyleith scanttering light generated,It indicates to pass through non-equilibrium interferometer
The intensity for the Reyleith scanttering light that long-armed light pulse generates at optical fiber z.
Since the polarization state and propagation constant of light pulse are related with optical wavelength, and transmit accumulated phase by light propagation constant and
Polarization state determines, the polarization state and accumulated phase φ of different wave length ingredient in Rayleigh signali,kDifference causes each in Rayleigh signal
The intensity I of wavelength componentsP=1,2Difference, i.e., each wavelength components intensity will not decline simultaneously in Rayleigh optical signal.Therefore, light
The AC signal amplitude of the interference light intensity I (z) of sensing passage at fine zAlways it can protect
It holds in stable level without declining.Using the interference signal I (z) being made of multi-wavelength Rayleigh signal, in conjunction with phase
Demodulation techniques can obtain signal phase φs, and avoid detecting noise penalty phenomenon caused by the decline of Rayleigh signal light intensity.
As shown in Fig. 2, the distributed fiber-optic sensor device based on multi-wavelength double light pulses of the present embodiment, including multi-wavelength
Double light pulses formation component 1, circulator 2, photodetector 3, data collector 4, signal processor 5 and signal generator 6；It is more
For generating multi-wavelength double light pulses, each pulse in multi-wavelength double light pulses includes wavelength double light pulses formation component 1
There are multiple wavelength components；Circulator 2 is used to multi-wavelength double light pulses injecting sensor fibre 7, and receives multi-wavelength double light pulses
The Rayleigh optical signal generated in sensor fibre 7, and export Rayleigh optical signal；Photodetector 3 is for detecting the output of circulator 2
Rayleigh optical signal interference light intensity；Data collector 4 is used to that the interference light intensity that photodetector 3 detects will to be acquired,
Obtain light intensity signal；Signal processor 5 is for calculating light intensity signal, the phase information of acquisition Rayleigh optical signal, to
Obtain the information of 7 sensed signal of sensor fibre；Signal generator 6 is used to be 1 sum number of multi-wavelength double light pulses formation component
Drive signal and clock sync signal are provided according to collector 4.
In the present embodiment, multi-wavelength double light pulses formation component 1 includes：Laser 11, bundling device 12, light intensity modulator
13, double light pulses modulation component 14；Laser 11 is used to generate the multiwavelength laser with multiple and different wavelength；Bundling device 12 is used
Beam is closed in multiwavelength laser is carried out space；Light intensity modulator 13 is used to modulate the intensity of multiwavelength laser, generates periodically weight
Multiple multi-wavelength monochromatic light pulse；Double light pulses modulation component 14 is for being modulated multi-wavelength monochromatic light pulse, by multi-wavelength list
Light pulse is modulated to the multi-wavelength double light pulses with preset phase difference.Laser 11 includes multiple narrow linewidth lasers.Each
Narrow linewidth laser generates a kind of laser of wavelength.In Fig. 2, including m narrow linewidth laser, narrow linewidth laser λ1It generates
Wavelength is λ1Laser, narrow linewidth laser λiGeneration wavelength is λiLaser, narrow linewidth laser λmGeneration wavelength is λmSwash
Light.The power for the laser with different wave length that m narrow linewidth laser generates is same or equivalent, quite refers in double light pulses
The difference power of each wavelength components is less than preset threshold value.Multiple laser with different wave length that multiple narrow linewidth lasers generate
Space is carried out by bundling device 12 and closes beam, and bundling device is wavelength division multiplexer.Light intensity modulator 13 is exported according to signal generator 6
Control wave is modulated the intensity of multiwavelength laser.
It should be noted that in the present embodiment, being not limited only to generate multi-wavelength double light pulses using aforesaid way, also
Published mode in the prior art may be used and device generates multi-wavelength double light pulses, such as utilize electro-optic intensity modulator
(Electro-optic intensity modulator, EOIM) carries out sinusoidal intensity modulation to Single wavelength laser, can swash
Light device centre wavelength both sides generate sideband, form multi-wavelength output, and the frequency interval of adjacent edge band is equal to sinusoidal intensity modulation
Modulating frequency；Specific equipment such as Photline MX-LN-10 electro-optic intensity modulators.Should all fall protection scope of the present invention it
It is interior.
In the present embodiment, double light pulses modulation component 14 includes the first coupler 141, non-equilibrium interferometer 142, phase
Poor modulator 143 and the second coupler 144；First coupler 141 is used for multi-wavelength monochromatic light impulses injection to non-equilibrium interference
Two light paths of instrument 142；Phase difference modulator 143 be used for the phase of laser in a light path in non-equilibrium interferometer 142 into
Row modulation；Second coupler 144 is used to the laser in two light paths carrying out space to close beam.Signal processor 5, which has, to be used for：Root
According to the signal strength information of Reyleith scanttering light, the phase information of Reyleith scanttering light is obtained by differential multiplication cross algorithm, to be sensed
The information of the information of 7 sensed signal of optical fiber, sensed signal includes amplitude, frequency and phase information；The letter of Reyleith scanttering light
Number strength information is the strength information of each wavelength components superposition in Reyleith scanttering light.
In the present embodiment, non-equilibrium interferometer 142 have long-armed 1421 and 1,422 two fiber arms of galianconism, long-armed 1421
Have preset arm poor between galianconism 1422.Phase difference modulator 143 is piezoelectric ceramics, is wrapped on long-armed 1421, according to
Phase-modulation is carried out to the light pulse in long-armed 1421 under the driving for the control signal that signal generator 6 exports.After ovennodulation
Long-armed 1421 in light pulse and the non-galianconism 1422 through ovennodulation in light pulse pass through the second coupler 144 close beam, shape
At multi-wavelength double light pulses.Sensor fibre 7 is injected by circulator 2 again.
In the present embodiment, under the action of inductive signal, the multi-wavelength double light pulses in sensor fibre 7 will produce Rayleigh
Light, Reyleith scanttering light are exported by circulator 2.The a certain wavelength components of a pulse (p=1,2) in multi-wavelength double light pulses
λI=1,2 ..., mThe intensity of Rayleigh optical signal the interference light intensity of Rayleigh scattering light everywhere is covered in optical fiber by light pulse, it is such as above-mentioned
Shown in formula (1).In sensor fibre 7 after the Rayleigh light output that sensed position generates, Reyleith scanttering light is obtained by photodetector 3
Interference light intensity, the interference light intensity of the sensing passage in sensor fibre 7 at the z of position meets as shown in above-mentioned formula (2).Due to light arteries and veins
The polarization state and propagation constant of punching are related with optical wavelength, and transmit accumulated phase and determined by light propagation constant and polarization state, Rayleigh
The polarization state of different wave length ingredient and accumulated phase φ in signali,kDifference leads to the intensity of each wavelength components in Rayleigh signal
IP=1,2Difference, i.e., each wavelength components intensity will not decline simultaneously in Rayleigh optical signal.Therefore, sensing passage at optical fiber z
The AC signal amplitude of interference light intensity I (z)Always stable level can be maintained at and
It is not in decline.It can be obtained in conjunction with Phase Demodulation Method of Optic using the interference signal I (z) being made of multi-wavelength Rayleigh signal
Signal phase φs, and avoid detecting noise penalty phenomenon caused by the decline of Rayleigh signal light intensity.
Above-mentioned only presently preferred embodiments of the present invention, is not intended to limit the present invention in any form.Although of the invention
Disclosed above with preferred embodiment, however, it is not intended to limit the invention.Therefore, every without departing from technical solution of the present invention
Content, technical spirit any simple modifications, equivalents, and modifications made to the above embodiment, should all fall according to the present invention
In the range of technical solution of the present invention protection.
Claims (10)
1. a kind of distributed fiber-optic sensor method based on multi-wavelength double light pulses, which is characterized in that include the following steps：
S1. multi-wavelength double light pulses are generated, and the multi-wavelength double light pulses are injected into sensor fibre, the double light arteries and veins of the multi-wavelength
Each pulse in punching includes multiple wavelength components；
S2. the interference of the Rayleigh optical signal and the corresponding sensing passage of the Rayleigh optical signal in the sensor fibre is obtained
Light intensity；
S3. the interference light intensity is calculated, obtains the phase information of the Rayleigh optical signal, to obtain the sense light
The information of fine sensed signal.
2. the distributed fiber-optic sensor method according to claim 1 based on multi-wavelength double light pulses, it is characterised in that：Institute
Stating has preset phase difference between two pulsed lights in double light pulses.
3. the distributed fiber-optic sensor method according to claim 2 based on multi-wavelength double light pulses, it is characterised in that：Institute
Double light pulses are stated to be generated by the non-equilibrium interferometer with default arm difference by pulsed light.
4. the distributed fiber-optic sensor method according to claim 2 based on multi-wavelength double light pulses, it is characterised in that：Institute
The difference power for stating each wavelength components in double light pulses is less than preset threshold value.
5. the distributed fiber-optic sensor method according to claim 4 based on multi-wavelength double light pulses, it is characterised in that：Institute
The specific steps for stating step S3 include：According to the signal strength information of the Reyleith scanttering light, obtained by differential multiplication cross algorithm
The phase information of Reyleith scanttering light, to obtain the information of the sensed signal of the sensor fibre, the letter of the sensed signal
Breath includes amplitude, frequency and phase information；The signal strength information of the Reyleith scanttering light is each wavelength components superposition in Reyleith scanttering light
Strength information.
6. a kind of distributed fiber-optic sensor device based on multi-wavelength double light pulses, it is characterised in that：Including the double light arteries and veins of multi-wavelength
Rush formation component (1), circulator (2), photodetector (3), data collector (4), signal processor (5) and signal generator
(6)；
The multi-wavelength double light pulses formation component (1) is for generating multi-wavelength double light pulses, in the multi-wavelength double light pulses
Each pulse include multiple wavelength components；
The circulator (2) is used for multi-wavelength double light pulses injection sensor fibre (7), and receives the double light of the multi-wavelength
The Rayleigh optical signal that pulse generates in the sensor fibre (7), and export the Rayleigh optical signal；
The photodetector (3) is used to detect the interference light intensity of the Rayleigh optical signal of the circulator (2) output；
The interference light intensity that the data collector (4) is used to detect the acquisition photodetector (3), obtains
Light intensity signal；
The signal processor (5) is used to calculate the light intensity signal, obtains the phase information of the Rayleigh optical signal,
To obtain the information of the sensor fibre (7) sensed signal；
The signal generator (6) is used to carry for the multi-wavelength double light pulses formation component (1) and the data collector (4)
For drive signal and clock sync signal.
7. the distributed fiber-optic sensor device according to claim 6 based on multi-wavelength double light pulses, it is characterised in that：Institute
Stating multi-wavelength double light pulses formation component (1) includes：Laser (11), bundling device (12), light intensity modulator (13), double light pulses
Modulation component (14)；
The laser (11) is used to generate the multiwavelength laser with multiple and different wavelength；
The bundling device (12) is used to the multiwavelength laser carrying out space to close beam；
The light intensity modulator (13) is used to modulate the intensity of the multiwavelength laser, generates the multi-wavelength monochromatic light being repeated cyclically
Pulse；
The double light pulses modulation component (14) is for being modulated the multi-wavelength monochromatic light pulse, by the multi-wavelength monochromatic light
Impulse modulation is the multi-wavelength double light pulses with preset phase difference.
8. the distributed fiber-optic sensor device according to claim 7 based on multi-wavelength double light pulses, it is characterised in that：Institute
It includes multiple narrow linewidth lasers (11) to state laser (11).
9. the distributed fiber-optic sensor device according to claim 7 based on multi-wavelength double light pulses, it is characterised in that：Institute
It includes the first coupler (141), non-equilibrium interferometer (142), phase difference modulator (143) to state double light pulses modulation component (14)
With the second coupler (144)；
First coupler (141) is used for the multi-wavelength monochromatic light impulses injection to the non-equilibrium interferometer (142)
Two light paths；
The phase difference modulator (143) be used for the phase of laser in a light path in the non-equilibrium interferometer (142) into
Row modulation；
Second coupler (144) is used to the laser in two light paths carrying out space to close beam.
10. the distributed fiber-optic sensor device according to claim 9 based on multi-wavelength double light pulses, it is characterised in that：
The signal processor (5), which has, to be used for：According to the signal strength information of the Reyleith scanttering light, obtained by differential multiplication cross algorithm
The phase information for obtaining Reyleith scanttering light, to obtain the information of the sensed signal of the sensor fibre, the sensed signal
Information includes amplitude, frequency and phase information；The signal strength information of the Reyleith scanttering light is each wavelength components superposition in Reyleith scanttering light
Strength information.
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