CN109443590A - Phase sensitivity type OTDR and measurement method based on frequency-airspace matching and injection locking technique - Google Patents
Phase sensitivity type OTDR and measurement method based on frequency-airspace matching and injection locking technique Download PDFInfo
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- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/18—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge using photoelastic elements
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Abstract
The present invention provides a kind of phase sensitivity type OTDR and measurement method based on frequency-airspace matching and injection locking technique.Phase sensitivity type OTDR includes pulsed light sequence generating device and echo-signal detection device；Pulsed light sequence generating device includes main laser, from laser, electrooptic modulator, acousto-optic modulator, arbitrary waveform generator, arbitrary-function generator and first annular device；Echo-signal detection device includes the first erbium-doped fiber amplifier, the second circulator, the second erbium-doped fiber amplifier and photodetector.Above-mentioned technology realizes the quick tuning to laser frequency using any wave modulation system injection locking technique, fundamentally avoids the nonlinear problem in frequency sweeping process, has high-precision sensing capability.The present invention uses frequency domain-airspace matching technique to the demodulation of data, is matched by the frequency domain information to more airspace points, is substantially reduced the demand that data demodulation counts to frequency domain, substantially reduces the requirement to hardware bandwidth, expand measurement range.
Description
Technical field
Embodiments of the present invention are related to field of sensing technologies, more specifically, embodiments of the present invention are related to a kind of base
Yu Pin-airspace matching and injection locking technique phase sensitivity type OTDR and measurement method.
Background technique
Relative to other distributed sensing technologies, the phase-sensitive optical time domain reflectometer (Φ-based on Rayleigh scattering effect
OTDR) technology has the advantages that structure is simple, high sensitivity.The technology by into optical fiber inject narrow linewidth laser pulse,
The interference superposed signal of the backward Rayleigh scattering light in half pulse width is obtained, this interference superposed signal is to ambient temperature or strain
Change extremely sensitive.The Strength Changes of echo-signal show that the response sensitivity of temperature or strain is able to reach mK and n ε
Magnitude.
Φ-OTDR technique difficult point is the quantitative measurment to temperature or strain.Frequency domain correlation method is that one kind may be implemented to determine
A kind of technology of measurement.The method carries out correlation to the echo-signal of multiple frequencies on frequency domain, calculates temperature with this or answers
Variation.The method is without decline noise problem.The frequency sweep points that current frequency domain correlation method needs are more, and bandwidth demand amount is big, leads
It causes its measurement range small, significantly constrains the practical application value of the technology in terms of economy and practicability two.Moreover, at present
Frequency domain relevant programme use microwave-tuned method or Internal modulation methods, the former sweep velocity is slow, and measuring speed is low, can not be moved
State measurement, the latter's fm linearity is low, and measurement accuracy is low.
Summary of the invention
In the present context, embodiments of the present invention are intended to provide a kind of based on the matching of frequency-airspace and injection locking skill
The phase sensitivity type OTDR and measurement method of art, to solve, measurement range existing for existing frequency domain correlation Φ-OTDR art is small and band
The big problem of wide demand, to realize the dynamic measurement of a wide range of, highly sensitive temperature or strain.
In the first aspect of embodiment of the present invention, provide a kind of based on the matching of frequency-airspace and injection locking technique
Phase sensitivity type OTDR, including pulsed light sequence generating device and echo-signal detection device；The pulsed light sequence generating device
Including main laser, from laser, electrooptic modulator, acousto-optic modulator, arbitrary waveform generator, arbitrary-function generator and
One circulator；The echo-signal detection device is put including the first erbium-doped fiber amplifier, the second circulator, the second Er-doped fiber
Big device and photodetector；The output laser of the main laser is modulated by the electrooptic modulator, modulated laser via
The first annular device injection is described from laser, wherein the frequency of the modulated signal of the electrooptic modulator makees step change
Change, which is generated by the arbitrary waveform generator；The output light from laser is defeated through the first annular device
Out to the acousto-optic modulator, through the modulated pulsed light sequence of the acousto-optic modulator via first Erbium-doped fiber amplifier
After device amplification, again through in second circulator injection testing fiber；Wherein, the arbitrary-function generator is default for generating
Square-wave signal export to the acousto-optic modulator；Backward Rayleigh scattering echo-signal in the testing fiber is through described second
Circulator is exported to second erbium-doped fiber amplifier, and the backward Rayleigh scattering echo-signal is through second Er-doped fiber
It is detected after amplifier amplification by the photodetector.
It further, further include filter, the filter is set to second erbium-doped fiber amplifier and the photoelectricity
Between detector, for filtering out the spontaneous emission noise of second erbium-doped fiber amplifier.
In the second aspect of embodiment of the present invention, provide a kind of based on the matching of frequency-airspace and injection locking technique
Phase sensitivity type OTDR measurement method, the measurement method be based on as described above based on frequency-airspace match and injection locking technique
Phase sensitivity type OTDR realize；The measurement method includes: to generate the pulsed light sequence generating device in the first sending time
The first pulsed light sequence inputting described in echo-signal detection device, received in the first receiving time by the photodetector
The first backward Rayleigh scattering echo-signal corresponding with the first pulsed light sequence, wherein the first pulsed light sequence
Detecting optical pulses including n preset frequency；N is positive integer；In the second sending time by the pulsed light sequence generating device
Echo-signal detection device described in the second pulsed light sequence inputting generated passes through the photodetector in the second receiving time
Receive the second backward Rayleigh scattering echo-signal corresponding with the second pulsed light sequence, wherein second pulsed light
Sequence includes the detecting optical pulses of the n preset frequency；Wherein, second sending time first sending time it
Afterwards；The first backward Rayleigh scattering echo-signal includes each detecting optical pulses in the first pulsed light sequence described
Backward Rayleigh scattering echo-signal in testing fiber each position, the second backward Rayleigh scattering echo-signal include described
Each detecting optical pulses in two pulsed light sequences are rear to Rayleigh scattering echo-signal in the testing fiber each position；It obtains
The the first frequency domain-spatial feature figure and the second backward Rayleigh scattering for obtaining the first backward Rayleigh scattering echo-signal return
The second frequency domain-spatial feature figure of wave signal；Wherein, the first frequency domain-spatial feature figure and the second frequency domain-spatial feature figure
It is one-dimensional coordinate with the position on testing fiber, with the frequency of detecting optical pulses is two-dimensional coordinate, with the photodetection
Device received signal intensity or signal amplitude are third dimension coordinate；Pre- scale is chosen in the first frequency domain-spatial feature figure
Very little reference data region determines the corresponding matched data in reference data region in the second frequency domain-spatial feature figure
Region calculates the reference data region and displacement of the matched data region on two-dimensional coordinate, according to the position
Shifting amount determines the frequency delay between the first frequency domain-spatial feature figure and the second frequency domain-spatial feature figure；According to institute
Frequency delay is stated, the temperature variation or strain variation amount of the testing fiber are calculated.
Further, the reference data region includes preset first position in the first frequency domain-spatial feature figure
The data point of the predefined size neighborhood of point；Determine that the reference data region is corresponding in the second frequency domain-spatial feature figure
The step of matched data region include: in the second frequency domain-spatial feature figure, will be with the preset first position point
The data point of predefined size neighborhood of the identical second position point of one-dimensional coordinate be formed by data area as to be matched
Data area；The second dimension reference axis by data area to be matched along the second frequency domain-spatial feature figure moves, and is moved
It moves the difference matrix between resulting data area to be matched and the reference data region every time in the process, and calculates each
The quadratic sum of all elements of resulting difference matrix；Determine the quadratic sum of all elements of the difference matrix in moving process most
Difference matrix corresponding to hour, using the corresponding data area to be matched of the difference matrix as the matched data region.
Further, the step of calculating the temperature variation or strain variation amount of the testing fiber includes: according to as follows
Formula calculates the strain variation amount of the testing fiber:
Wherein, Δ v indicates that frequency delay, v indicate light wave fundamental frequency, pεIndicate that elasto-optical coefficient, Δ ε indicate strain knots modification, Kε
Indicate the coefficient of strain.
Further, the temperature variation of the testing fiber is calculated according to the following formula:
Wherein, Δ v indicates that frequency delay, v indicate that light wave fundamental frequency, ξ indicate that thermo-optical coeffecient, α indicate thermal expansion coefficient, Δ T
Indicate that temperature knots modification, KT indicate temperature coefficient.
According to the present invention embodiment based on frequency-airspace matching and injection locking technique phase sensitivity type OTDR with measure
Method has the advantages that
The present invention realizes the quick tuning to laser frequency using any wave modulation system injection locking technique.The technology is from root
The nonlinear problem in frequency sweeping process is avoided in sheet, and there is high-precision sensing capability.
In addition, the technology utilizes any wave modulation technique, frequency tuning speed is greatly improved, has this technology pair
The measurement capability of quick variable signal.
The present invention uses frequency domain-airspace matching technique to the demodulation of data, change before this technology only to the frequency of a point
Domain information carries out relevant strategy.It is matched by the frequency domain information to more airspace points, is significantly reduced data demodulation to frequency
The demand of domain points, (prior art bandwidth is about 4GHz, can be with using the present invention for the requirement for substantially reducing to hardware bandwidth
Be reduced to 500MHz, can be reduced to original tape it is wide 1/8), expand the measurement range of system.
Detailed description of the invention
The following detailed description is read with reference to the accompanying drawings, above-mentioned and other mesh of exemplary embodiment of the invention
, feature and advantage will become prone to understand.In the accompanying drawings, if showing by way of example rather than limitation of the invention
Dry embodiment, in which:
Fig. 1 is the phase sensitivity type based on frequency-airspace matching and injection locking technique for showing embodiment according to the present invention
The light channel structure schematic diagram of OTDR；
Fig. 2 is the phase sensitivity type based on frequency-airspace matching and injection locking technique for showing embodiment according to the present invention
The flow chart of one exemplary process of the measurement method of OTDR；
Fig. 3 is a flow chart that may be handled for showing the step S250 in Fig. 2；
Fig. 4 is to show frequency domain-airspace matching method schematic diagram；
Fig. 5 A is the schematic diagram for showing optical fiber different location received signal Strength Changes situation；
Fig. 5 B be show signal-to-noise ratio it is low when change in signal strength schematic diagram；
Fig. 5 C is to show one-dimensional related operation method and the demodulation result of two dimensional image matching method under different window length to compare
Schematic diagram.
In the accompanying drawings, identical or corresponding label indicates identical or corresponding part.
Specific embodiment
The principle and spirit of the invention are described below with reference to several illustrative embodiments.It should be appreciated that providing this
A little embodiments are used for the purpose of making those skilled in the art can better understand that realizing the present invention in turn, and be not with any
Mode limits the scope of the invention.On the contrary, these embodiments are provided so that this disclosure will be more thorough and complete, and energy
It is enough that the scope of the present disclosure is completely communicated to those skilled in the art.
Embodiment according to the present invention proposes a kind of phase sensitivity type based on frequency-airspace matching and injection locking technique
OTDR and measurement method.
Herein, it is to be understood that any number of elements in attached drawing be used to example rather than limit and it is any
Name is only used for distinguishing, without any restrictions meaning.
Below with reference to several representative embodiments of the invention, the principle and spirit of the present invention are explained in detail.
Exemplary means
The embodiment provides a kind of phase sensitivity type (i.e. phases based on frequency-airspace matching and injection locking technique
Responsive type) optical time domain reflectometer (OTDR, Optical Time Domain Reflectometer), including the production of pulsed light sequence
Generating apparatus and echo-signal detection device；The pulsed light sequence generating device includes main laser, from laser, Electro-optical Modulation
Device, acousto-optic modulator, arbitrary waveform generator, arbitrary-function generator and first annular device；The echo-signal detection device
Including the first erbium-doped fiber amplifier, the second circulator, the second erbium-doped fiber amplifier and photodetector；The main laser
Output laser modulated by the electrooptic modulator, modulated laser is described from laser via the first annular device injection
In, wherein the frequency of the modulated signal of the electrooptic modulator makees Spline smoothing, which is occurred by the random waveform
Device generates；The output light from laser is exported through the first annular device to the acousto-optic modulator, through the acousto-optic tune
The modulated pulsed light sequence of device processed is injected via after first erbium-doped fiber amplifier amplification, again through second circulator
In testing fiber；Wherein, the arbitrary-function generator is exported for generating preset square-wave signal to the acousto-optic modulator；
Backward Rayleigh scattering echo-signal in the testing fiber, which is exported through second circulator to second Er-doped fiber, puts
Big device, the backward Rayleigh scattering echo-signal are visited after second erbium-doped fiber amplifier amplification by the photodetector
It surveys.
Fig. 1 shows the phase sensitivity type OTDR of the invention based on frequency-airspace matching and injection locking technique, including pulse
Light sequence generating device and echo-signal detection device.
As shown in Figure 1, pulsed light sequence generating device includes main laser 1-1 (LASER1 shown in FIG. 1), from laser
Device 1-2 (LASER2 shown in FIG. 1), electrooptic modulator (EOM) 1-3, acousto-optic modulator (AOM) 1-4, arbitrary waveform generator
(AWG) 1-5, arbitrary-function generator (AFG) 1-6 and first annular device (AOM) 1-7.
Echo-signal detection device includes the first erbium-doped fiber amplifier (EDFA1 shown in FIG. 1) 1-8, the second circulator
1-9, the second erbium-doped fiber amplifier (EDFA2 shown in FIG. 1) 1-10 and photodetector (PD) 1-11.
The output laser of main laser 1-1 is modulated by electrooptic modulator 1-3, and modulated laser is as injection light via
One circulator 1-7 is injected from laser 1-2, wherein the frequency of the modulated signal of electrooptic modulator 1-3 makees Spline smoothing (rank
The interval that transition represents frequency variation is identical, such as v0, v0+5MHz, v0+10MHz, v0+15MHz etc.), modulation letter
It number is generated by arbitrary waveform generator 1-5.Wherein, the modulated signal of arbitrary waveform generator 1-5 for example can rule of thumb be set
It sets, or can also be arranged by the method for test, which is not described herein again.
It is exported from the output light of laser 1-2 through first annular device 1-7 to acousto-optic modulator 1-4, through acousto-optic modulator 1-4
Modulated pulsed light sequence injects light to be measured via after the first erbium-doped fiber amplifier 1-8 amplification, again through the second circulator 1-9
In fibre.
Wherein, the output light wavelength of main laser 1-1 is, for example, 1550.09nm.Each light pulse in pulsed light sequence
Width is, for example, 20ns, and peak power is, for example, 1W.
It is, for example, semiconductor laser from laser 1-2.
Electrooptic modulator 1-3 is used to the microwave signal that arbitrary waveform generator exports being loaded into light wave, to carry out frequency
Rate modulation.
The continuous light modulation that acousto-optic modulator 1-4 is used to export from laser 1-2 is at pulsed light.
As shown in Figure 1, entering through the modulated laser of electrooptic modulator 1-3 from the first port a1 of first annular device 1-7
First annular device 1-7 is exported from the second port a2 of first annular device 1-7 and is input to as injection light from laser 1-2, from
The laser of laser 1-2 output enters first annular device 1-7 from the second port a2 of first annular device 1-7 again, wherein and then from
The third port a3 of first annular device 1-7 is exported to acousto-optic modulator 1-4.
Arbitrary-function generator 1-6 is exported for generating preset square-wave signal to acousto-optic modulator 1-4.Preset square wave
Signal for example can be rule of thumb arranged, or can also be arranged by the method for test, and which is not described herein again.
Wherein, change from the output light frequency of laser 1-2 with the variation of injection light frequency.In other words, work as injection
Light frequency is f0When, output light frequency is f0；When injection light frequency becomes f1When, output light frequency also becomes f1；When injection optical frequency
Rate is f2When, corresponding output light frequency also becomes f2；Etc., and kept constant from the output power of laser 1-2.
Backward Rayleigh scattering echo-signal in testing fiber is exported through the second circulator 1-9 to the second Erbium-doped fiber amplifier
Device 1-10, backward Rayleigh scattering echo-signal are visited after the second erbium-doped fiber amplifier 1-10 amplification by photodetector 1-11
It surveys.
As an example, the above-mentioned phase sensitivity type OTDR based on the matching of frequency-airspace and injection locking technique can also include filtering
Device, filter is for example between the second erbium-doped fiber amplifier 1-10 and photodetector 1-11, for filtering out the second er-doped
The spontaneous emission noise of fiber amplifier 1-10.
Illustrative methods
The embodiments of the present invention also provide a kind of phase sensitivity type OTDR's based on the matching of frequency-airspace and injection locking technique
Measurement method, the measurement method are real based on the phase sensitivity type OTDR as described above based on the matching of frequency-airspace and injection locking technique
It is existing；The measurement method includes: the first pulsed light sequence for generating the pulsed light sequence generating device in the first sending time
Column input the echo-signal detection device, are received and first pulse in the first receiving time by the photodetector
The corresponding first backward Rayleigh scattering echo-signal of light sequence, wherein the first pulsed light sequence includes n predetermined frequencies
The detecting optical pulses of rate；N is positive integer；In the second pulse that the second sending time generates the pulsed light sequence generating device
Echo-signal detection device described in light sequence inputting is received and described second in the second receiving time by the photodetector
The corresponding second backward Rayleigh scattering echo-signal of pulsed light sequence, wherein the second pulsed light sequence includes the n
The detecting optical pulses of preset frequency；Wherein, second sending time is after first sending time；Described first is backward
Rayleigh scattering echo-signal includes each detecting optical pulses in the first pulsed light sequence in the testing fiber each position
On backward Rayleigh scattering echo-signal, the second backward Rayleigh scattering echo-signal includes in the second pulsed light sequence
Each detecting optical pulses it is rear to Rayleigh scattering echo-signal in the testing fiber each position；It is backward to obtain described first
Second frequency of the first frequency domain-spatial feature figure of Rayleigh scattering echo-signal and the second backward Rayleigh scattering echo-signal
Domain-spatial feature figure；Wherein, the first frequency domain-spatial feature figure and the second frequency domain-spatial feature figure are on testing fiber
Position is one-dimensional coordinate, take the frequency of detecting optical pulses as two-dimensional coordinate, strong with the photodetector received signal
Degree or signal amplitude are third dimension coordinate；The reference data area of predetermined size is chosen in the first frequency domain-spatial feature figure
Domain, determines the corresponding matched data region in the reference data region in the second frequency domain-spatial feature figure, described in calculating
Reference data region and displacement of the matched data region on two-dimensional coordinate, to determine described the according to the displacement
Frequency delay between one frequency domain-spatial feature figure and the second frequency domain-spatial feature figure；According to the frequency delay, meter
Calculate the temperature variation or strain variation amount of the testing fiber.
Fig. 2 schematically shows the phases based on frequency-airspace matching and injection locking technique according to the embodiment of the present disclosure
A kind of illustrative process flow 200 of the measurement method of quick type OTDR.
As shown in Fig. 2, in step S210, in the first arteries and veins that the first sending time generates pulsed light sequence generating device
It washes sequence inputting echo-signal detection device off, is received and the first pulsed light in the first receiving time by photodetector 1-11
The corresponding first backward Rayleigh scattering echo-signal of sequence, wherein the first pulsed light sequence includes the detection of n preset frequency
Light pulse；N is positive integer.
It is defeated in the second pulsed light sequence that the second sending time generates pulsed light sequence generating device in step S220
Enter echo-signal detection device, it is opposite with the second pulsed light sequence by photodetector 1-11 reception in the second receiving time
The backward Rayleigh scattering echo-signal of second answered, wherein the second pulsed light sequence includes the detecting optical pulses of n preset frequency.
N preset frequency be, for example, from n frequency frequency f1 to frequency f2, such as according to from small to large or from
Arrive small sequence arrangement greatly, that is, the pulse in the first and second pulsed light sequences be according to frequency from small to large or from greatly to
What small sequence successively issued.N is, for example, 50,100 or other integers.Among n preset frequency, every two adjacent frequency
Between interval it is for example identical, or can also be at least partly different.
For example, n preset frequency can be 100 frequencies from 5MHz to 500MHz, between two neighboring frequency for example
Between be divided into 5MHz, above-mentioned n preset frequency such as can for 5MHz, 10MHz, 15MHz ..., 500MHz.
Wherein, the second sending time is after the first sending time；First backward Rayleigh scattering echo-signal includes first
Each detecting optical pulses in pulsed light sequence are rear backward to Rayleigh scattering echo-signal, second in testing fiber each position
Rayleigh scattering echo-signal include each detecting optical pulses in the second pulsed light sequence in testing fiber each position it is rear to
Rayleigh scattering echo-signal.
In step S230, the first frequency domain-spatial feature figure and the of the first backward Rayleigh scattering echo-signal is obtained
The second frequency domain-spatial feature figure of two backward Rayleigh scattering echo-signals；Wherein, the first frequency domain-spatial feature figure and the second frequency
Domain-spatial feature figure with the position on testing fiber be one-dimensional coordinate, be with the frequency of detecting optical pulses two-dimensional coordinate, with
Photodetector 1-11 received signal intensity or signal amplitude are third dimension coordinate.For example, the first, second, and third dimension coordinate
It can be indicated respectively with X-coordinate, Y-coordinate and the Z coordinate in XYZ coordinate system.
Wherein, received backward Rayleigh scattering echo-signal (as after the first or second to Rayleigh scattering echo-signal) institute is right
The position on testing fiber answered can be determined according to such as under type: in the first pulsed light sequence and the second pulsed light sequence
Each pulse for, the sending time of the pulse is known and is denoted as t0, after the pulse that photodetector 1-11 is received
It is, for example, from t to the Rayleigh scattering echo-signal corresponding duration1To t2(that is, from t1Moment initially receives the pulse
Backward Rayleigh scattering echo-signal, t2Reception terminates), then by t1That signal strength that reception arrives (or signal width
Value) start position as testing fiber position, by t2That signal strength (or signal amplitude) that reception arrives as to
Survey the final position (such as fiber lengths L) of fiber position.If using the start position of testing fiber position as 0 point, light to be measured
The final position of fine positionWherein, c indicates the transmission speed of light in a fiber.
In step S240, the reference data region of predetermined size is chosen in the first frequency domain-spatial feature figure.
As an example, in such as the first frequency domain-spatial feature figure of reference data region preset first position point it is predetermined
The data point of big small neighbourhood.
In step s 250, the corresponding matched data in reference data region is determined in the second frequency domain-spatial feature figure
Region.
As an example, step S250 can for example be realized by step S310-S330 shown in Fig. 3.
The processing of above-mentioned steps S310-S330 is described in conjunction with Fig. 4.
Fig. 4 gives frequency domain-airspace matching method schematic diagram.Left figure in Fig. 4 shows light under a certain temperature or strain value
Frequency sweep result (example as the first frequency domain-spatial feature figure) along fibre, frequency sweep when right figure shows temperature or strain change
As a result (example as the second frequency domain-spatial feature figure).That is, two figure of Fig. 4 left and right respectively indicates two moment not equality of temperature
The echo-signal of multiple frequency sonding light under degree or strain value.
It should be noted that the first frequency domain-spatial feature figure and the second frequency domain-spatial feature figure are used two in Fig. 4
The form for tieing up figure indicates, that is to say, that in Fig. 4, abscissa indicates the position on testing fiber, and ordinate indicates detection light arteries and veins
The frequency of punching, and photodetector 1-11 received signal intensity or signal amplitude then use brightness of image or gray scale to indicate (i.e.
Different signal strengths or signal amplitude is presented as the point of different brightness or different gray scales in Fig. 4).
For example, it is assumed that the coordinate of preset first position point is (xP, yP, zP), that is, the of preset first position point
One-dimensional, two-dimensional coordinate is (xP, yP), it is assumed that predefined size neighborhood is with the point (xP, yP) centered on ZW×tWThe square of size
Shape (wherein, ZWFor the size on one-dimensional coordinate, tWFor the size on two-dimensional coordinate).In other words, this preset first
Set point (xP, yP) predefined size neighborhood in data point composed by data area be one-dimensional coordinateIn range, two-dimensional coordinateData institute group in range
At region.As shown in figure 4, the M in the first frequency domain-spatial feature figure (left figure) indicates reference data region.
It in step s310, will be with preset in the second frequency domain-spatial feature figure (as shown in the right figure in Fig. 4)
The data point of the predefined size neighborhood of the identical second position point of the one-dimensional coordinate of one location point is formed by data area work
For data area to be matched.
Wherein, the initial position of second position point selected in the second frequency domain-spatial feature figure can be with it is above-mentioned
Identical any point (the x of one-dimensional coordinate of first position point in first frequency domain-spatial feature figurep, y'p), that is to say, that the
The one-dimensional coordinate of the initial position of two location points is equal to the one-dimensional coordinate x of first position pointp, and second position point is initial
The two-dimensional coordinate y' of positionpIt can be with the two-dimensional coordinate y of first position pointPDifference, can also be identical.In this way, number to be matched
According to one-dimensional coordinate in region i.e. the second frequency domain-spatial feature figureRange is interior, the second dimension is sat
MarkRegion S composed by data in range.
In step s 320, by data area S to be matched along the second frequency domain-spatial feature figure two-dimensional coordinates (i.e.
Frequency axis in Fig. 4) it is mobile, obtain moved every time in moving process resulting data area to be matched and reference data region it
Between difference matrix, and calculate every time resulting difference matrix all elements quadratic sum.That is, in the second frequency domain-
After the initial position for selecting second position point in spatial feature figure, by enabling, the one-dimensional coordinate of second position point is constant, changes
Become the mode of two-dimensional coordinate to move second position point, thus to obtain the data area to be matched after each movement, and then obtains
To corresponding difference matrix.
Wherein, by data area S to be matched along the two-dimensional coordinates (i.e. in Fig. 4 of the second frequency domain-spatial feature figure
Frequency axis) mobile mode can be there are many implementation.
For example, data area S to be matched is mobile along the side (such as upside in Fig. 4) of said frequencies axis, it moves every time
Dynamic step-length is preset value (can set, or be determined by the method for test based on experience value etc.), when being moved to image side
When boundary, returns initial position and moves data area S to be matched along the other side (downside in such as Fig. 4) of said frequencies axis,
The step-length moved every time is still preset value, until being moved to boundary.A mobile step-length every time, obtains difference square described above
Battle array, and calculate the quadratic sum of all elements of difference matrix.
Or data area S to be matched can successively be moved according to preset step-length (along frequency from side boundary
Axis), until being moved to another lateral boundaries, and every time move a step-length when, obtain difference matrix described above, and
Calculate the quadratic sum of all elements of difference matrix.
In step S330, determine corresponding when the quadratic sum minimum of all elements of the difference matrix in moving process
Difference matrix, using the corresponding data area to be matched of the difference matrix as matched data region.
Such as, it is assumed that entire moving process moves 100 times in total, has obtained 100 difference matrix, has selected this 100
That the smallest difference matrix of the quadratic sum of all elements in difference matrix, by the corresponding data area to be matched of the difference matrix
S is as matched data region.
In step S260, reference data region and displacement of the matched data region on two-dimensional coordinate are calculated, with
The frequency delay between the first frequency domain-spatial feature figure and the second frequency domain-spatial feature figure is determined according to the displacement.
Wherein, reference data region for example can be according to respective with displacement of the matched data region on two-dimensional coordinate
The distance between central point calculates (can also be according to other methods), for example, the center position in reference data region is
(xP, yP), the center position in matched data region is (xP, y'P), then reference data region and matched data region are second
The displacement tieed up on coordinate is y'P-yP.That is, frequency delay is equal to y'P-yP。
Then, in step S270, according to frequency delay, the temperature variation or strain variation amount of testing fiber are calculated.
Wherein, above-mentioned temperature variation or strain variation amount are temperature variation or strain variation amount in time of measuring, i.e., to be measured
Optical fiber is from the first sending time to the temperature variation of the second sending time or strain variation amount.
As an example, in step S270, such as the strain variation amount Δ ε of testing fiber can be calculated according to formula one.
Formula one:
In formula one, Δ v indicates that frequency delay, v indicate light wave fundamental frequency, pεIndicate that elasto-optical coefficient, Δ ε indicate that strain changes
Variable, wherein v and pεFor known constant, KεIndicate the coefficient of strain, Kε=-1+pε。
In addition, as an example, in step S270, such as the temperature change of testing fiber can be calculated according to formula two
Measure Δ T.
Formula two:
In formula two, Δ v indicates that frequency delay, v indicate that light wave fundamental frequency, ξ indicate that thermo-optical coeffecient, α indicate thermal expansion system
Number, Δ T indicate temperature knots modification, wherein ξ and α is known constant,
KTIndicate temperature coefficient, KT=-(ξ+α).
As can be seen from the above description, in the measurement method of the embodiment of the present invention, the demodulation of data uses frequency domain-airspace
Matching technique.When demodulating the temperature or strain variation value of a certain position, the number of spatial neighborhood at selection Fig. 4 left figure position or so
As pattern matrix M (i.e. reference data region), the rectangular area S in Fig. 4 right figure at same position is moved along frequency axis at strong point
It is dynamic, it will subtract each other to obtain difference matrix with the element of homography S in moving process, calculate square of difference matrix all elements
With, the amount of movement of matrix S corresponding when quadratic sum minimum is recorded, the frequency delay amount of two figures of left and right is determined with this amount of movement,
Temperature regulating or strain variation are solved with this.
This patent propose carried out using two dimensional image matching method data demodulation done relative to multiple spatial position points it is flat
Equal mode has better stability and the tolerance to noise.As shown in Figure 5A, fiber position 10.5m- is selected
The data of 11.5m are demodulated, and it is as shown in Figure 5 B that 11m position signal intensity changes over time situation, it can be seen that noise compares
It is low.Average and two dimensional image matching algorithm is sat to multiple positions using one-dimensional cross correlation algorithm respectively and carries out data demodulation (to obtain
Obtain frequency delay), experimental result is as shown in Figure 5 C, it can be seen that the demodulation performance of image matching algorithm is much better than one-dimensional cross-correlation
Algorithm.Wherein, what the 1D method in Fig. 5 C referred to is above-mentioned one-dimensional cross correlation algorithm, and what 2D method therein referred to is above-mentioned
Two dimensional image matching algorithm.
In addition, although describing the operation of the method for the present invention in the accompanying drawings with particular order, this do not require that or
Hint must execute these operations in this particular order, or have to carry out shown in whole operation be just able to achieve it is desired
As a result.Additionally or alternatively, it is convenient to omit multiple steps are merged into a step and executed by certain steps, and/or by one
Step is decomposed into execution of multiple steps.
Although detailed description of the preferred embodimentsthe spirit and principles of the present invention are described by reference to several, it should be appreciated that, this
It is not limited to the specific embodiments disclosed for invention, does not also mean that the feature in these aspects cannot to the division of various aspects
Combination is benefited to carry out, this to divide the convenience merely to statement.The present invention is directed to cover appended claims spirit and
Included various modifications and equivalent arrangements in range.
Claims (6)
1. the phase sensitivity type OTDR based on frequency-airspace matching and injection locking technique, it is characterised in that generated including pulsed light sequence
Device and echo-signal detection device；
The pulsed light sequence generating device includes main laser (1-1), from laser (1-2), electrooptic modulator (1-3), sound
Optical modulator (1-4), arbitrary waveform generator (1-5), arbitrary-function generator (1-6) and first annular device (1-7)；
The echo-signal detection device includes the first erbium-doped fiber amplifier (1-8), the second circulator (1-9), the second er-doped
Fiber amplifier (1-10) and photodetector (1-11)；
The output laser of the main laser (1-1) is modulated by the electrooptic modulator (1-3), and modulated laser is via described
First annular device (1-7) injection is described from laser (1-2), wherein the frequency of the modulated signal of the electrooptic modulator (1-3)
Rate makees Spline smoothing, which is generated by the arbitrary waveform generator (1-5)；
The output light from laser (1-2) is exported through the first annular device (1-7) to the acousto-optic modulator (1-4),
After the modulated pulsed light sequence of the acousto-optic modulator (1-4) is via first erbium-doped fiber amplifier (1-8) amplification,
Again through in second circulator (1-9) injection testing fiber；Wherein, the arbitrary-function generator (1-6) is pre- for generating
If square-wave signal export to the acousto-optic modulator (1-4)；
Backward Rayleigh scattering echo-signal in the testing fiber, which is exported through second circulator (1-9) to described second, mixes
Doped fiber amplifier (1-10), the backward Rayleigh scattering echo-signal are amplified through second erbium-doped fiber amplifier (1-10)
It is detected afterwards by the photodetector (1-11).
2. the phase sensitivity type OTDR according to claim 1 based on frequency-airspace matching and injection locking technique, it is characterised in that
It further include filter, the filter is set to second erbium-doped fiber amplifier (1-10) and the photodetector (1-11)
Between, for filtering out the spontaneous emission noise of second erbium-doped fiber amplifier (1-10).
3. the measurement method of the phase sensitivity type OTDR based on the matching of frequency-airspace and injection locking technique, which is characterized in that the measurement side
Method is realized based on the phase sensitivity type OTDR of any of claims 1 or 2 based on the matching of frequency-airspace and injection locking technique；The survey
Amount method includes:
The letter of the echo described in the first pulsed light sequence inputting that the first sending time generates the pulsed light sequence generating device
Number detection device is received in the first receiving time by the photodetector (1-11) opposite with the first pulsed light sequence
The backward Rayleigh scattering echo-signal of first answered, wherein the first pulsed light sequence includes the detection light arteries and veins of n preset frequency
Punching；N is positive integer；
The letter of the echo described in the second pulsed light sequence inputting that the second sending time generates the pulsed light sequence generating device
Number detection device is received in the second receiving time by the photodetector (1-11) opposite with the second pulsed light sequence
The backward Rayleigh scattering echo-signal of second answered, wherein the second pulsed light sequence includes the detection of the n preset frequency
Light pulse；
Wherein, second sending time is after first sending time；The first backward Rayleigh scattering echo-signal
It is rear to Rayleigh scattering in the testing fiber each position including each detecting optical pulses in the first pulsed light sequence
Echo-signal, the second backward Rayleigh scattering echo-signal include each detecting optical pulses in the second pulsed light sequence
It is rear to Rayleigh scattering echo-signal in the testing fiber each position；
Obtain the first frequency domain-spatial feature figure and the second backward Rayleigh of the described first backward Rayleigh scattering echo-signal
The second frequency domain-spatial feature figure of scatter echo signal；Wherein, the first frequency domain-spatial feature figure and the second frequency domain-airspace
Characteristic pattern with the position on testing fiber is one-dimensional coordinate, with the frequency of detecting optical pulses is two-dimensional coordinate, with the light
Electric explorer (1-11) received signal intensity or signal amplitude are third dimension coordinate；
The reference data region of predetermined size is chosen in the first frequency domain-spatial feature figure,
The corresponding matched data region in the reference data region is determined in the second frequency domain-spatial feature figure,
The reference data region and displacement of the matched data region on two-dimensional coordinate are calculated, according to the displacement
Measure the frequency delay determined between the first frequency domain-spatial feature figure and the second frequency domain-spatial feature figure；
According to the frequency delay, the temperature variation or strain variation amount of the testing fiber are calculated.
4. the measurement method of the phase sensitivity type OTDR according to claim 3 based on the matching of frequency-airspace and injection locking technique,
It is characterized in that, the reference data region includes the pre- of preset first position point in the first frequency domain-spatial feature figure
The data point of fixed big small neighbourhood；
The step of corresponding matched data region in the reference data region is determined in the second frequency domain-spatial feature figure is wrapped
It includes:
In the second frequency domain-spatial feature figure, by identical with the one-dimensional coordinate of the preset first position point
The data point of the predefined size neighborhood of two location points is formed by data area as data area to be matched；
The second dimension reference axis by data area to be matched along the second frequency domain-spatial feature figure moves, and obtains moving process
In move difference matrix between resulting data area to be matched and the reference data region every time, and calculate gained every time
Difference matrix all elements quadratic sum；
Difference matrix corresponding when the quadratic sum minimum of all elements of the difference matrix in moving process is determined, by the difference
The corresponding data area to be matched of matrix is as the matched data region.
5. the measurement side of the phase sensitivity type OTDR according to claim 3 or 4 based on the matching of frequency-airspace and injection locking technique
Method, which is characterized in that the step of calculating the temperature variation or strain variation amount of the testing fiber include:
The strain variation amount of the testing fiber is calculated according to the following formula:
Wherein, Δ v indicates that frequency delay, v indicate light wave fundamental frequency, pεIndicate that elasto-optical coefficient, Δ ε indicate strain knots modification, KεIt indicates
The coefficient of strain.
6. the phase sensitivity type OTDR based on frequency-airspace matching and injection locking technique according to any one of claim 3-5
Measurement method, which is characterized in that
The temperature variation of the testing fiber is calculated according to the following formula:
Wherein, Δ v indicates that frequency delay, v indicate that light wave fundamental frequency, ξ indicate that thermo-optical coeffecient, α indicate that thermal expansion coefficient, Δ T indicate
Temperature knots modification, KTIndicate temperature coefficient.
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