CN107246847A - A kind of strain sensing system detected based on the flight time and its method for sensing - Google Patents
A kind of strain sensing system detected based on the flight time and its method for sensing Download PDFInfo
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- CN107246847A CN107246847A CN201710367022.5A CN201710367022A CN107246847A CN 107246847 A CN107246847 A CN 107246847A CN 201710367022 A CN201710367022 A CN 201710367022A CN 107246847 A CN107246847 A CN 107246847A
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
Abstract
The invention discloses a kind of strain sensing system detected based on the flight time and its method for sensing.The present invention is by the microwave signal synchronous with reference laser pulse train, and exploring laser light pulse train through strain transducer together sends into the second optical fiber loop light microwave phase detector, the acquisition error signal relevant with strain；It is big using microwave signal measurement scope, it is high using optical fiber loop light microwave phase detector detection accuracy；The present invention realizes high-precision static strain and dynamic strain sensing simultaneously, and with big dynamic range；Use the pulse laser of free-running, it is not necessary to complicated laser stabilising arrangement and signal processing algorithm, in the case where realizing close resolution ratio, dynamic range, cost performance is higher；Equally there is high resolution ratio and big dynamic range in long-range monitoring strain；In pulse laser, mode-locked laser is such as used, then with broader spectrum, good durability can be obtained.
Description
Technical field
The present invention relates to strain sensing technology, and in particular to it is a kind of based on the flight time detect strain sensing system and its
Method for sensing.
Background technology
Fibre optic strain sensor has due to its excellent robustness, flexibility and sensitivity in science and engineering field
Important application.In in the past few decades, different types of optical strain sensor is continued to bring out.For example, based on Brillouin
The strain transducer of scattering can monitor optical fiber in a distributed manner with the strain resolution of millimetre-sized spatial resolution and microstrain
Strain in link, the strain transducer of Fiber Bragg Grating FBG type can be realized to receive and answer in microstrain magnitude dynamic range
Become static state (being less than 10Hz) strain measurement of magnitude and dynamic (being more than 10Hz) strain measurement of Ya Pi strain magnitudes.Due to high
Cost performance, good flexibility and strong anti-electromagnetic interference capability, a part of strain transducer commercialization.Recently, it is double
The introducing of optical comb technology so that the strain transducer of Fiber Bragg Grating FBG type is in milli strain dynamic range, and being received up to 34 should
The resolution ratio of change.
Although Da Yapi strains magnitude to the resolution ratio of dynamic strain sensing, the resolution ratio of static strain is made an uproar due to 1/f
Sound (from laser and environmental perturbation Middle and low frequency noise) and be difficult to improve.Therefore, sensed for high-precision static strain
For, it is often necessary to additional reference source (such as stable optical frequency com, Atomic absorption line or just the same but without strain
Sensing head) compensate the slow change of environment temperature.In this static strain method for sensing, coordinate narrow linewidth continuous wave laser
Fiber Bragg grating sensor can realize highest resolution ratio.For fiber Bragg grating sensor, sweep-frequency Békésy audiometer and solid
Determining the continuous laser of wavelength type has utilization.The scheme of sweep-frequency Békésy audiometer can provide up to 10 resolution ratio for receiving strain, but frequency is swept
Data reading speed can usually be influenceed by retouching, and make it be difficult to improve, generally in below 10Hz.In addition, the resolution of this scheme
Rate is also influenceed by the non-linear and non-ideal repeatability of spectral scan.The scheme of non-sweep-frequency Békésy audiometer can overcome these to limit, low
Frequent section, resolution ratio receives strain magnitude up to Asia.In this scheme, continuous wave laser passes through Pound-Drever-Hall
(PDH) technology is locked on optical reference source.Using double PDH feedback loops, newest achievement realize 10Hz nearby 10p ε/
Hz1/2Resolution ratio.However, because laser lock-on and error signal detection process are complicated, the dynamic range of this scheme and multiplexing
Property is simultaneously bad.Therefore, how the multiplexing capacity that high resolution ratio, fast speed of detection, big dynamic range are become reconciled is realized simultaneously,
It is the problem that current static strain sensing is run into.
The content of the invention
The problem of being run into the prior art for more than, the present invention proposes a kind of strain biography detected based on the flight time
Sensing system and its method for sensing, by exploring laser light pulse train because strain causes the change of flight time, to be strained
Sensing, to realize in big dynamic range while obtaining high static state and dynamic strain resolution ratio.
It is an object of the present invention to propose a kind of strain sensing system detected based on the flight time.
The strain sensing system of the present invention is divided into local strain sensing system and long-range strain according to the distance of detection range
Sensor-based system, is respectively used to proximity detection and remote probe, remotely refers to more than 1km.
The local strain sensing system detected based on the flight time of the present invention is included：Pulse laser, fiber optic splitter,
First optical fiber loop light-microwave phase detector, proportional, integral feed back control system, microwave source, strain transducer, the second light
Fine loop light-microwave phase detector and data acquisition device；Wherein, pulse laser output laser pulse sequence；Through optical fiber
Beam splitter is divided into two parts, respectively reference laser pulse train and exploring laser light pulse train；Reference laser pulse train is passed through
Optical fiber is transmitted to the first optical fiber loop light-microwave phase detector, and the microwave signal of microwave source output is also transmitted to first
Optical fiber loop light-microwave phase detector, the first optical fiber loop light-microwave phase detector obtain reference laser pulse train and
The phase error signal of microwave signal；Phase error signal is transmitted to proportional, integral feed back control system is entered again, produces control letter
Number, transmit to microwave source；Microwave source is adjusted control signal so that the microwave signal and reference laser arteries and veins of microwave source output
Rush sequence synchronization；Exploring laser light pulse train passes through strain transducer, transmits to the second optical fiber loop light-microwave phase detection
Device, due to the strain at strain transducer, the light path that exploring laser light pulse train is undergone changes, so that detection swashs
The flight delay of light pulse sequence changes；The microwave signal synchronous with reference laser pulse train is also transmitted to the second light
Fine loop light-microwave phase detector；Second optical fiber loop light-microwave phase detector on the basis of microwave signal, obtain with
The relevant error signal of strain, is read by data acquisition device；Data acquisition device is believed by analyzing the error relevant with strain
Number it is delayed, so as to obtain the strain information at strain transducer.
The long-range strain sensing system detected based on the flight time of the present invention is included：Local side part, fiber optical circulator
And distal portions；Wherein, local side part include pulse laser, the first and second optical fiber loop light-microwave phase detector,
Proportional, integral feed back control system, microwave source, the first and second fiber amplifiers, the first wavelength division multiplexer and data collection dress
Put；Distal portions include the second wavelength division multiplexer, the first speculum, strain transducer and the second speculum；Local side part
Pulse laser output laser pulse sequence；Transmitted through Transmission Fibers and dispersion compensating fiber to the first end of optical fiber circulator
Mouthful, exported through second port to the second wavelength division multiplexer of distal portions；Second wavelength division multiplexer demultiplexes laser pulse sequence
With for two parts, respectively reference laser pulse train and exploring laser light pulse train；Reference laser pulse train is passed through optical fiber
Transport to and the second wavelength division multiplexer is returned after the first speculum, reflection；Exploring laser light pulse train by strain transducer transmit to
Second speculum is returned, and again passes by strain transducer, light path changes, so as to change delay, returns to the second wavelength-division multiplex
Device；Reference laser pulse train and exploring laser light pulse train are multiplexed with light beam by the second wavelength division multiplexer, are transmitted to optical fiber
The second port of circulator, is exported by the 3rd port, is transmitted through Transmission Fibers and dispersion compensating fiber to the of local side part
One wavelength division multiplexer；First wavelength division multiplexer laser pulse sequence is demultiplexing as two parts, respectively reference laser pulse train
The exploring laser light pulse train changed with delay；Reference laser pulse train is transmitted to first after amplifying through the first fiber amplifier
Optical fiber loop light-microwave phase detector, and microwave source output microwave signal also transmit to the first optical fiber loop light-microwave
Phase detector, the first optical fiber loop light-microwave phase detector obtains the phase of reference laser pulse train and microwave signal
Error signal；Phase error signal is transmitted to proportional, integral feed back control system is entered again, is produced control signal, is transmitted to microwave
Source；Microwave source is adjusted control signal so that the microwave signal of microwave source output is synchronous with reference laser pulse train；Visit
Survey after laser pulse sequence is amplified through the second fiber amplifier and transmit to the second optical fiber loop light-microwave phase detector；With
The synchronous microwave signal of reference laser pulse train is also transmitted to the second optical fiber loop light-microwave phase detector；Second optical fiber
Loop light-microwave phase detector obtains the error signal relevant with strain, is read by data acquisition device；Data acquisition device
It is delayed by the error signal for analyzing relevant with strain, so as to obtain the strain information at strain transducer.
Pulse laser, which is used, to be mixed bait locked mode femto second optical fiber laser, mixes bait locked mode psec optical fiber laser, solid pulse
One kind in laser and semiconductor pulse laser.
Microwave source uses VCXO or dielectric oscillator.
For the high frequency strain more than 1Hz, data acquisition device uses Fourier spectrum analyzer, for less than 1Hz's
Low frequency is strained, and data acquisition device uses data collecting card.
It is another object of the present invention to provide a kind of strain sensing method detected based on the flight time.
The strain sensing method of the present invention is divided into local strain sensing method and long-range strain according to the distance of detection range
Method for sensing, is respectively used to proximity detection and remote probe, remotely refers to more than 1km.
The local strain sensing method detected based on the flight time of the present invention, detection range is less than 1km, including following step
Suddenly：
1) pulse laser output laser pulse sequence；
2) laser pulse sequence is divided into two parts, respectively reference laser pulse train and exploring laser light through fiber optic splitter
Pulse train；
3) reference laser pulse train is transmitted to the first optical fiber loop light-microwave phase detector, and microwave through optical fiber
The microwave signal of source output is also transmitted to the first optical fiber loop light-microwave phase detector, the first optical fiber loop light-microwave phase
Detector obtains the phase error signal of reference laser pulse train and microwave signal；
4) phase error signal is transmitted to proportional, integral feed back control system is entered again, is produced control signal, is transmitted to microwave
Source；Microwave source is adjusted control signal so that the microwave signal of microwave source output is synchronous with reference laser pulse train；
5) exploring laser light pulse train passes through strain transducer, transmits to the second optical fiber loop light-microwave phase detector,
Due to the strain at strain transducer, the light path of exploring laser light pulse train changes, so that exploring laser light pulse sequence
The flight delay of row changes；The microwave signal synchronous with reference laser pulse train is also transmitted to the second optical fiber loop
Light-microwave phase detector；
6) the second optical fiber loop light-microwave phase detector obtains the error relevant with strain on the basis of microwave signal
Signal, is read by data acquisition device；
7) data acquisition device is delayed by analyzing the error signal relevant with strain, so as to obtain strain transducer
The strain information at place.
The long-range strain sensing method detected based on the flight time of the present invention, detection range is more than 1km, including following
Step：
1) the pulse laser output laser pulse sequence of local side part；Transmitted through Transmission Fibers and dispersion compensating fiber
To the first port of optical fiber circulator, exported through second port to the second wavelength division multiplexer of distal portions；
2) laser pulse sequence is demultiplexing as two parts by the second wavelength division multiplexer, respectively reference laser pulse train and
Exploring laser light pulse train；
3) reference laser pulse train is transmitted to the first speculum through optical fiber, and the second wavelength division multiplexer is returned after reflection；
4) exploring laser light pulse train is transmitted to the second speculum by strain transducer and returned, and again passes by strain sensing
Device, due to strain, light path changes, so that pulse flight delay changes, returns to the second wavelength division multiplexer；
5) reference laser pulse train and exploring laser light pulse train are multiplexed with light beam by the second wavelength division multiplexer, transmission
To the second port of optical fiber circulator, exported, transmitted through Transmission Fibers and dispersion compensating fiber to local end by the 3rd port
The first wavelength division multiplexer divided；
6) the first wavelength division multiplexer laser pulse sequence is demultiplexing as two parts, respectively reference laser pulse train and prolongs
When the exploring laser light pulse train that changes；
7) reference laser pulse train is transmitted to the first optical fiber loop light-microwave phase after amplifying through the first fiber amplifier
Detector, and microwave source output microwave signal also transmit to the first optical fiber loop light-microwave phase detector, the first optical fiber
Loop light-microwave phase detector obtains the phase error signal of reference laser pulse train and microwave signal；
8) phase error signal is transmitted to proportional, integral feed back control system is entered again, is produced control signal, is transmitted to microwave
Source；Microwave source is adjusted control signal so that the microwave signal of microwave source output is synchronous with reference laser pulse train；
9) exploring laser light pulse train is transmitted to the second optical fiber loop light-microwave phase after amplifying through the second fiber amplifier
Detector；The microwave signal synchronous with reference laser pulse train is also transmitted to the second optical fiber loop light-microwave phase detection
Device；
10) the second optical fiber loop light-microwave phase detector obtains the error relevant with strain on the basis of microwave signal
Signal, is read by data acquisition device；
11) data acquisition device is delayed by analyzing the error signal relevant with strain, so as to obtain strain sensing
Strain information at device.
Advantages of the present invention：
The present invention is by the microwave signal synchronous with reference laser pulse train, and the exploring laser light pulse through strain transducer
Sequence together sends into the second optical fiber loop light-microwave phase detector, obtains the error signal relevant with strain；Believed using microwave
Number measurement range is big, high using optical fiber loop light-microwave phase detector detection accuracy；The present invention realizes high-precision quiet simultaneously
State is strained and dynamic strain sensing, and with big dynamic range；Use the pulse laser of free-running, it is not necessary to complicated
Laser stabilising arrangement and signal processing algorithm, in the case where realizing close resolution ratio, dynamic range, cost performance is higher；
Equally there is high resolution ratio and big dynamic range during long-range monitoring strain；In pulse laser, mode-locked laser is such as used, then is had
There is broader spectrum, good durability can be obtained.
Brief description of the drawings
Fig. 1 is the structured flowchart of the local strain sensing system detected based on the flight time of the present invention；
Fig. 2 is optical fiber loop light in the strain sensing system detected based on the flight time of the present invention-microwave phase detection
The structured flowchart of one embodiment of device；
Fig. 3 is the measurement range of one embodiment of the local strain sensing system detected based on the flight time of the present invention
Result figure；
Fig. 4 is the resolution ratio table of one embodiment of the local strain sensing system detected based on the flight time of the present invention
Levy result figure；
Fig. 5 is the structured flowchart of the long-range strain sensing system detected based on the flight time of the present invention；
Fig. 6 is the result figure of one embodiment of the long-range strain sensing system detected based on the flight time of the present invention.
Embodiment
Below in conjunction with the accompanying drawings, by specific embodiment, the present invention is expanded on further.
Embodiment one
In the present embodiment, strain sensing system detection range is less than 1km, is local strain sensing system.
As shown in figure 1, the local strain sensing system detected based on the flight time of the present embodiment is included：Pulse laser
Device, fiber optic splitter, the first optical fiber loop light-microwave phase detector, proportional, integral feed back control system, microwave source, strain
Sensor, the second optical fiber loop light-microwave phase detector and data acquisition device；Wherein, pulse laser output laser arteries and veins
Rush sequence；It is divided into two parts, respectively reference laser pulse train and exploring laser light pulse train through fiber optic splitter；With reference to sharp
Light pulse sequence is transmitted to the first optical fiber loop light-microwave phase detector, and the microwave signal of microwave source output through optical fiber
Also transmit to the first optical fiber loop light-microwave phase detector, the first optical fiber loop light-microwave phase detector is obtained with reference to sharp
The phase error signal of light pulse sequence and microwave signal；Phase error signal transmit again to enter proportional, integral feedback control dress
Put, produce control signal, transmit to microwave source；Microwave source is adjusted control signal so that the microwave letter of microwave source output
It is number synchronous with reference laser pulse train；Exploring laser light pulse train passes through strain transducer, transmit to the second optical fiber loop light-
Microwave phase detector, due to the strain at strain transducer, the light path of exploring laser light pulse train changes, so that
The flight delay of exploring laser light pulse train changes；The microwave signal synchronous with reference laser pulse train also transmit to
Second optical fiber loop light-microwave phase detector；Second optical fiber loop light-microwave phase detector on the basis of microwave signal,
The error signal relevant with strain is obtained, is read by data acquisition device；Data acquisition device passes through the error relevant with strain
Signal is delayed, so as to obtain the strain information at strain transducer.
In the present embodiment, pulse laser uses er-doped locked mode femto second optical fiber laser, repetition rate 250MHz, spectrum width
70nm；The score ratio 50 of fiber optic splitter:50；Two parts that fiber optic splitter is divided into, the power per part is 18mW；Microwave source
Using VCXO, 8GHz microwave is produced；The locking strip of proportional, integral feed back control system is wider than 100kHz；Strain is passed
Sensor uses 40.8m fiber stretcher, and the electric signal for applying 3kHz, 35mVrms is used as calibration signal；For more than 1Hz's
High frequency strain, data acquisition device uses Fourier spectrum analyzer, is strained for the low frequency less than 1Hz, data acquisition device
Using data collecting card.
As shown in Fig. 2 optical fiber loop light-microwave phase detector includes：Fiber optical circulator, optic fiber ring-shaped cavity and light level
Weigh detector；Optic fiber ring-shaped cavity including two multiply two couplers, first collimator, the first Faraday rotator, quarter-wave plate,
Second Faraday rotator, 1/2nd wave plates, the second collimater, electrooptic modulator；The output of pulse laser multiplies as two
The input of two couplers, the output of microwave source is as the input of electrooptic modulator, and two multiply the output of two couplers as light level
The input of weighing apparatus detector, error signal can be obtained from the output of photoelectricity balanced detector.
Fig. 3 and Fig. 4 is the measurement range result figure of the local strain transducer detected based on the flight time of the present embodiment
With resolution representation result figure；As seen from Figure 3, detection strain, has very big measurement range more than 180 μ ε；Can by Fig. 4
To find out, the system detection strain, with very high resolution ratio, is 18p ε/Hz at 1Hz1/2, it is 1.9p ε/Hz at 3kHz1 /2。
Embodiment two
In the present embodiment, strain sensing system carries out remote probe, and more than detection range 1km is long-range strain sensing
System.
As shown in figure 5, the long-range strain sensing system detected based on the flight time of the present embodiment is included：Local end
Point, fiber optical circulator and distal portions；Wherein, local side part includes pulse laser, the first and second optical fiber loop light-micro-
Wave phase detector, proportional, integral feed back control system, microwave source, the first and second fiber amplifiers, the first wavelength division multiplexer
And data acquisition device；Distal portions include the second wavelength division multiplexer, the first speculum, strain transducer and the second speculum；
The pulse laser output laser pulse sequence of local side part；Transmitted through Transmission Fibers and dispersion compensating fiber to fiber annular
The first port of device, is exported to the second wavelength division multiplexer of distal portions through second port；Second wavelength division multiplexer is by laser arteries and veins
Rush sequence and be demultiplexing as two parts, respectively reference laser pulse train and exploring laser light pulse train；Reference laser pulse sequence
Row are transmitted to the first speculum through optical fiber, and the second wavelength division multiplexer is returned after reflection；Exploring laser light pulse train is passed through overstrain
Sensor is transmitted to the second speculum and returned, and again passes by strain transducer, light path changes, so as to change delay, return the
Two wavelength division multiplexers；Reference laser pulse train and exploring laser light pulse train are multiplexed with light beam by the second wavelength division multiplexer,
Transmit to the second port of optical fiber circulator, exported, transmitted through Transmission Fibers and dispersion compensating fiber to local by the 3rd port
Hold the first wavelength division multiplexer of part；First wavelength division multiplexer laser pulse sequence is demultiplexing as two parts, respectively with reference to sharp
The exploring laser light pulse train that light pulse sequence and delay change；After reference laser pulse train is amplified through the first fiber amplifier
Transmit to the first optical fiber loop light-microwave phase detector, and the microwave signal of microwave source output is also transmitted to the first optical fiber
Loop light-microwave phase detector, the first optical fiber loop light-microwave phase detector obtains reference laser pulse train and microwave
The phase error signal of signal；Phase error signal is transmitted to proportional, integral feed back control system is entered again, produces control signal,
Transmit to microwave source；Microwave source is adjusted control signal so that the microwave signal of microwave source output and reference laser pulse
Sequence synchronization；Exploring laser light pulse train is transmitted to the second optical fiber loop light-microwave phase after amplifying through the second fiber amplifier
Detector；The microwave signal synchronous with reference laser pulse train is also transmitted to the second optical fiber loop light-microwave phase detection
Device；Second optical fiber loop light-microwave phase detector obtains the error signal relevant with strain, is read by data acquisition device；
Data acquisition device is delayed by the error signal relevant with strain, so as to obtain the strain letter of strain transducer generation
Breath.
In the present embodiment, pulse laser uses er-doped locked mode femto second optical fiber laser, repetition rate 250MHz, spectrum width
70nm, power is 5mW；Microwave source uses VCXO, produces 8GHz microwave；The locking of proportional, integral feed back control system
Band is wider than 100kHz；Strain transducer uses 40.8m fiber stretcher；For the high frequency strain more than 1Hz, data acquisition
Device uses Fourier spectrum analyzer, is strained for the low frequency less than 1Hz, and data acquisition device uses data collecting card；Pass
Lose fine using 1km single-mode fibers；Dispersion compensating fiber is 100m；First and second wavelength division multiplexers first wave length section be
1550nm~1558nm, second wave length section is 1558nm~1566nm.
Fig. 6 is the strain sensing result figure of the long-range strain sensing system detected based on the flight time of the present embodiment；By
Fig. 6 can be seen that the system remote probe strain with very high resolution ratio, be 80p ε/Hz at 1Hz1/2, it is at 3kHz
2.2pε/Hz1/2, while the influence that the factors such as optical fiber link temperature are brought to measurement can be suppressed.
It is finally noted that, the purpose for publicizing and implementing example is that help further understands the present invention, but this area
Technical staff be appreciated that：Without departing from the spirit and scope of the invention and the appended claims, it is various to replace and repair
It is all possible for changing.Therefore, the present invention should not be limited to embodiment disclosure of that, and the scope of protection of present invention is to weigh
The scope that sharp claim is defined is defined.
Claims (10)
1. a kind of local strain sensing system detected based on the flight time, it is characterised in that the local strain sensing system
Including：Pulse laser, fiber optic splitter, the first optical fiber loop light-microwave phase detector, proportional, integral feedback control dress
Put, microwave source, strain transducer, the second optical fiber loop light-microwave phase detector and data acquisition device；Wherein, the arteries and veins
Rush laser output laser pulse sequence；It is divided into two parts, respectively reference laser pulse train and detection through fiber optic splitter
Laser pulse sequence；Reference laser pulse train is transmitted to the first optical fiber loop light-microwave phase detector through optical fiber, and micro-
The microwave signal of wave source output is also transmitted to the first optical fiber loop light-microwave phase detector, the first optical fiber loop light-microwave phase
Location probe obtains the phase error signal of reference laser pulse train and microwave signal；Phase error signal is transmitted to entering ratio again
Example-integral feedback control device, produces control signal, transmits to microwave source；Microwave source is adjusted control signal so that micro-
The microwave signal of wave source output is synchronous with reference laser pulse train；Exploring laser light pulse train passes through strain transducer, transmission
To the second optical fiber loop light-microwave phase detector, due to the strain at strain transducer, the light path of exploring laser light pulse train
Change, so that the flight delay of exploring laser light pulse train changes；It is synchronous with reference laser pulse train
Microwave signal also transmit to the second optical fiber loop light-microwave phase detector；Second optical fiber loop light-microwave phase detector
On the basis of microwave signal, the error signal relevant with strain is obtained, is read by data acquisition device；Data acquisition device passes through
The analysis error signal relevant with strain is delayed, so as to obtain the strain information at strain transducer.
2. local strain sensing system as claimed in claim 1, it is characterised in that the pulse laser, which is used, mixes bait locked mode
Femto second optical fiber laser, mix in bait locked mode psec optical fiber laser, solid pulse laser and semiconductor pulse laser one
Kind.
3. local strain sensing system as claimed in claim 1, it is characterised in that the microwave source uses VCXO or Jie
Matter oscillator.
4. local strain sensing system as claimed in claim 1, it is characterised in that for the high frequency strain more than 1Hz, data
Harvester uses Fourier spectrum analyzer, is strained for the low frequency less than 1Hz, and data acquisition device uses data acquisition
Card.
5. a kind of long-range strain sensing system detected based on the flight time, it is characterised in that the long-range strain sensing system
Including：Local side part, fiber optical circulator and distal portions；Wherein, the local side part includes pulse laser, the first and
Second optical fiber loop light-microwave phase detector, proportional, integral feed back control system, microwave source, the first and second fiber amplifiers
Device, the first wavelength division multiplexer and data harvester；The distal portions include the second wavelength division multiplexer, the first speculum, answered
Become sensor and the second speculum；The pulse laser output laser pulse sequence of the local side part；Through Transmission Fibers and
Dispersion compensating fiber is transmitted to the first port of optical fiber circulator, is exported through second port to the second wavelength-division multiplex of distal portions
Device；Laser pulse sequence is demultiplexing as two parts by the second wavelength division multiplexer, and respectively reference laser pulse train and detection swashs
Light pulse sequence；Reference laser pulse train is transmitted to the first speculum through optical fiber, and the second wavelength division multiplexer is returned after reflection；Visit
Survey laser pulse sequence to transmit to the return of the second speculum by strain transducer, again pass by strain transducer, light path occurs
Change, so as to change delay, return to the second wavelength division multiplexer；Second wavelength division multiplexer is by reference laser pulse train and spy
Survey laser pulse sequence and be multiplexed with light beam, transmit to the second port of optical fiber circulator, exported by the 3rd port, through transmission light
Fine and dispersion compensating fiber is transmitted to the first wavelength division multiplexer of local side part；The first wavelength division multiplexer laser pulse sequence
Row are demultiplexing as two parts, the exploring laser light pulse train that respectively reference laser pulse train and delay change；Reference laser
Pulse train is transmitted to the first optical fiber loop light-microwave phase detector, and microwave source after amplifying through the first fiber amplifier
The microwave signal of output is also transmitted to the first optical fiber loop light-microwave phase detector, and the first optical fiber loop light-microwave phase is visited
Survey the phase error signal that device obtains reference laser pulse train and microwave signal；Phase error signal transmit again to enter ratio-
Integral feedback control device, produces control signal, transmits to microwave source；Microwave source is adjusted control signal so that microwave
The microwave signal of source output is synchronous with reference laser pulse train；After exploring laser light pulse train is amplified through the second fiber amplifier
Transmit to the second optical fiber loop light-microwave phase detector；The microwave signal synchronous with reference laser pulse train is also transmitted
To the second optical fiber loop light-microwave phase detector；Second optical fiber loop light-microwave phase detector obtains relevant with strain
Error signal, is read by data acquisition device；Data acquisition device is delayed by analyzing the error signal relevant with strain,
So as to obtain the strain information at strain transducer.
6. long-range strain sensing system as claimed in claim 5, it is characterised in that the pulse laser, which is used, mixes bait locked mode
Femto second optical fiber laser, mix in bait locked mode psec optical fiber laser, solid pulse laser and semiconductor pulse laser one
Kind.
7. long-range strain sensing system as claimed in claim 5, it is characterised in that the microwave source uses VCXO or Jie
Matter oscillator.
8. long-range strain sensing system as claimed in claim 5, it is characterised in that described for the high frequency strain more than 1Hz
Data acquisition device uses Fourier spectrum analyzer, is strained for the low frequency less than 1Hz, and the data acquisition device uses number
According to capture card.
9. a kind of local strain sensing method detected based on the flight time, detection range is less than 1km, it is characterised in that described
Local strain sensing method comprises the following steps：
1) pulse laser output laser pulse sequence；
2) laser pulse sequence is divided into two parts, respectively reference laser pulse train and exploring laser light pulse through fiber optic splitter
Sequence；
3) reference laser pulse train is transmitted to the first optical fiber loop light-microwave phase detector through optical fiber, and microwave source is defeated
The microwave signal gone out is also transmitted to the first optical fiber loop light-microwave phase detector, the first optical fiber loop light-microwave phase detection
Device obtains the phase error signal of reference laser pulse train and microwave signal；
4) phase error signal is transmitted to proportional, integral feed back control system is entered again, is produced control signal, is transmitted to microwave source；
Microwave source is adjusted control signal so that the microwave signal of microwave source output is synchronous with reference laser pulse train；
5) exploring laser light pulse train passes through strain transducer, transmits to the second optical fiber loop light-microwave phase detector, due to
Strain at strain transducer, the light path of exploring laser light pulse train changes, so that exploring laser light pulse train
Flight delay changes；The microwave signal synchronous with reference laser pulse train is also transmitted to the second optical fiber loop light-micro-
Wave phase detector；
6) the second optical fiber loop light-microwave phase detector obtains the error signal relevant with strain on the basis of microwave signal,
Read by data acquisition device；
7) data acquisition device is delayed by analyzing the error signal relevant with strain, so as to obtain at strain transducer
Strain information.
10. a kind of long-range strain sensing method detected based on the flight time, detection range is more than 1km, it is characterised in that remote
Journey strain sensing method comprises the following steps：
1) the pulse laser output laser pulse sequence of local side part；Transmitted through Transmission Fibers and dispersion compensating fiber to light
The first port of fine circulator, is exported to the second wavelength division multiplexer of distal portions through second port；
2) laser pulse sequence is demultiplexing as two parts, respectively reference laser pulse train and detection by the second wavelength division multiplexer
Laser pulse sequence；
3) reference laser pulse train is transmitted to the first speculum through optical fiber, and the second wavelength division multiplexer is returned after reflection；
4) exploring laser light pulse train is transmitted to the second speculum by strain transducer and returned, and again passes by strain transducer,
Due to strain, light path changes, so that pulse flight delay changes, returns to the second wavelength division multiplexer；
5) reference laser pulse train and exploring laser light pulse train are multiplexed with light beam by the second wavelength division multiplexer, are transmitted to light
The second port of fine circulator, is exported by the 3rd port, is transmitted through Transmission Fibers and dispersion compensating fiber to local side part
First wavelength division multiplexer；
6) the first wavelength division multiplexer laser pulse sequence is demultiplexing as two parts, and respectively reference laser pulse train and delay changes
The exploring laser light pulse train of change；
7) reference laser pulse train is transmitted to the first optical fiber loop light-microwave phase after amplifying through the first fiber amplifier and detected
Device, and microwave source output microwave signal also transmit to the first optical fiber loop light-microwave phase detector, the first optical fiber loop
Light-microwave phase detector obtains the phase error signal of reference laser pulse train and microwave signal；
8) phase error signal is transmitted to proportional, integral feed back control system is entered again, is produced control signal, is transmitted to microwave source；
Microwave source is adjusted control signal so that the microwave signal of microwave source output is synchronous with reference laser pulse train；
9) exploring laser light pulse train is transmitted to the second optical fiber loop light-microwave phase after amplifying through the second fiber amplifier and detected
Device；The microwave signal synchronous with reference laser pulse train is also transmitted to the second optical fiber loop light-microwave phase detector；
10) the second optical fiber loop light-microwave phase detector obtains the error letter relevant with strain on the basis of microwave signal
Number, read by data acquisition device；
11) data acquisition device is delayed by analyzing the error signal relevant with strain, so as to obtain at strain transducer
Strain information.
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| CN112671457A (en) * | 2020-12-03 | 2021-04-16 | 北京无线电计量测试研究所 | Double-base-station radar reference frequency synchronization system and method |
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| CN101059333A (en) * | 2006-04-21 | 2007-10-24 | 都灵无线基金会 | System and method for measuring distances, displacement and mechanical actions |
| CN101839698A (en) * | 2010-04-30 | 2010-09-22 | 南京大学 | BOTDR (Brillouin Optical Time Domain Reflectometer) for calibrating optical power of reference light and calibrating method thereof |
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| JPS5569006A (en) * | 1978-11-21 | 1980-05-24 | Nippon Telegr & Teleph Corp <Ntt> | Strain measuring method for optical fiber |
| US4717253A (en) * | 1985-11-22 | 1988-01-05 | Massachusetts Institute Of Technology | Optical strain gauge |
| CN101059333A (en) * | 2006-04-21 | 2007-10-24 | 都灵无线基金会 | System and method for measuring distances, displacement and mechanical actions |
| CN101839698A (en) * | 2010-04-30 | 2010-09-22 | 南京大学 | BOTDR (Brillouin Optical Time Domain Reflectometer) for calibrating optical power of reference light and calibrating method thereof |
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