CN107246847B - A kind of strain sensing system and its method for sensing based on flight time detection - Google Patents
A kind of strain sensing system and its method for sensing based on flight time detection Download PDFInfo
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- CN107246847B CN107246847B CN201710367022.5A CN201710367022A CN107246847B CN 107246847 B CN107246847 B CN 107246847B CN 201710367022 A CN201710367022 A CN 201710367022A CN 107246847 B CN107246847 B CN 107246847B
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- 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
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Abstract
The invention discloses a kind of strain sensing systems and its method for sensing based on flight time detection.The present invention is by the microwave signal synchronous with reference laser pulse train, and exploring laser light pulse train through strain transducer is fed together the second optical fiber loop light-microwave phase detector, obtains and strains related error signal；It is big using microwave signal measurement range, 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 has big dynamic range；Using the pulse laser of free-running, complicated laser stabilising arrangement and signal processing algorithm are not needed, 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 there is broader spectrum, can get good reusability.
Description
Technical field
The present invention relates to strain sensing technologies, and in particular to it is a kind of based on the flight time detection strain sensing system and its
Method for sensing.
Background technique
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, being based on Brillouin
The strain transducer of scattering can monitor optical fiber with the strain resolution of millimetre-sized spatial resolution and microstrain in a distributed manner
The strain transducer of strain in link, fiber bragg grating type can be realized to receive and be answered in microstrain magnitude dynamic range
Static state (being less than 10Hz) strain measurement of variable grade and dynamic (being greater than 10Hz) strain measurement of Ya Pi strain magnitude.Due to high
Cost performance, good flexibility and strong anti-electromagnetic interference capability, the commercialization of a part of strain transducer.Recently, double
The introducing of optical comb technology, so that the strain transducer of fiber bragg grating type is received up to 34 and answered in milli strain dynamic range
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, high-precision static strain is sensed
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, cooperation narrow linewidth continuous wave laser
Highest resolution ratio may be implemented in fiber Bragg grating sensor.For fiber Bragg grating sensor, sweep-frequency Békésy audiometer and solid
The continuous laser for determining 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
It retouches and usually will affect data reading speed, be difficult to improve it, usually in 10Hz or less.In addition to this, the resolution of this scheme
Rate is also influenced by the non-linear and non-ideal repeatability of spectral scan.The scheme of non-sweep-frequency Békésy audiometer can overcome these limitations, low
Frequent section, resolution ratio are received up to Asia and strain magnitude.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, since laser lock-on and error signal detection process are complicated, the dynamic range and multiplexing of this scheme
Property is simultaneously bad.Therefore, how high resolution ratio, fast speed of detection, big dynamic range and good multiplexing capacity to be realized simultaneously,
It is the problem that current static strain sensing is encountered.
Summary of the invention
Aiming at the problem that encountering in the prior art above, the invention proposes a kind of strain biographies based on flight time detection
Sensing system and its method for sensing lead to the change of flight time, due to straining by exploring laser light pulse train to be strained
Sensing obtains high static state and dynamic strain resolution ratio to realize simultaneously in big dynamic range.
An object of the present invention is to provide a kind of strain sensing systems based on flight time detection.
Strain sensing system of the 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 1km or more.
The local strain sensing system based on flight time detection of the invention include: 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 warp
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 again into proportional, integral feed back control system, generates control letter
Number, it is transmitted to microwave source；Microwave source is adjusted in 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, is transmitted to the second optical fiber loop light-microwave phase detection
Device, due to the strain at strain transducer, exploring laser light pulse train light path experienced 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
Related error signal is strained, is read by data acquisition device；Data acquisition device is believed by analysis with related error is strained
It number is delayed, to obtain the strain information at strain transducer.
Long-range strain sensing system based on flight time detection of the invention includes: local end part, fiber optical circulator
And distal portions；Wherein, local end 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 acquisition dress
It sets；Distal portions include the second wavelength division multiplexer, the first reflecting mirror, strain transducer and the second reflecting mirror；Local end part
Pulse laser output laser pulse sequence；The first end of optical fiber circulator is transmitted to through transmission fiber and dispersion compensating fiber
Mouthful, it exports 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
The first reflecting mirror is transported to, the second wavelength division multiplexer is returned after reflection；Exploring laser light pulse train is transmitted to by strain transducer
Second reflecting mirror returns, and again passes by strain transducer, and light path changes, 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 third port, is transmitted to the of local end part through transmission fiber and dispersion compensating fiber
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 the amplification of the first fiber amplifier
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 obtain the phase of reference laser pulse train and microwave signal
Error signal；Phase error signal is transmitted to again into proportional, integral feed back control system, is generated control signal, is transmitted to microwave
Source；Microwave source is adjusted in control signal, so that the microwave signal of microwave source output is synchronous with reference laser pulse train；It visits
It surveys laser pulse sequence and is transmitted to the second optical fiber loop light-microwave phase detector after the amplification of the second fiber amplifier；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 and strains related error signal, is read by data acquisition device；Data acquisition device
It is delayed by analysis with related error signal is strained, to obtain the strain information at strain transducer.
Pulse laser, which uses, to be mixed bait mode locking femto second optical fiber laser, mixes bait mode locking picosecond optical fiber laser, solid pulse
One of laser and semiconductor pulse laser.
Microwave source uses voltage controlled crystal oscillator or dielectric oscillator.
For being greater than the high frequency strain of 1Hz, data acquisition device uses Fourier spectrum analyzer, for less than 1Hz's
Low frequency strain, data acquisition device use data collecting card.
It is another object of the present invention to provide a kind of strain sensing methods based on flight time detection.
Strain sensing method of the 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 1km or more.
Local strain sensing method based on flight time detection of the invention, detection range are less than 1km, including following step
It is rapid:
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 again into proportional, integral feed back control system, is generated control signal, is transmitted to microwave
Source；Microwave source is adjusted in 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, is transmitted 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 column 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 is obtained on the basis of microwave signal and is strained related error
Signal is read by data acquisition device；
7) data acquisition device is delayed by analysis with related error signal is strained, to obtain strain transducer
The strain information at place.
Long-range strain sensing method based on flight time detection of the invention, detection range are 1km or more, including following
Step:
1) the pulse laser output laser pulse sequence of local end part；It is transmitted through transmission fiber and dispersion compensating fiber
To the first port of optical fiber circulator, export 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 reflecting mirror through optical fiber, and the second wavelength division multiplexer is returned after reflection；
4) exploring laser light pulse train is transmitted to the return of the second reflecting mirror by strain transducer, again passes by strain sensing
Device, due to strain, light path changes, so that pulse flight delay be made to change, 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
It to the second port of optical fiber circulator, is exported by third port, is transmitted to local end through transmission fiber and dispersion compensating fiber
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 the amplification of the first fiber amplifier
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 the phase error signal of reference laser pulse train and microwave signal；
8) phase error signal is transmitted to again into proportional, integral feed back control system, is generated control signal, is transmitted to microwave
Source；Microwave source is adjusted in 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 the amplification of 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 is obtained on the basis of microwave signal and is strained related error
Signal is read by data acquisition device；
11) data acquisition device is delayed by analysis with related error signal is strained, 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 is fed together the second optical fiber loop light-microwave phase detector, obtains and strains related error signal；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 strain and dynamic strain sensing, and there is big dynamic range；Using the pulse laser of free-running, complexity is not needed
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 when long-range monitoring strain；In pulse laser, mode-locked laser is such as used, then is had
There is broader spectrum, can get good reusability.
Detailed description of the invention
Fig. 1 is the structural block diagram of the local strain sensing system of the invention based on flight time detection；
Fig. 2 is optical fiber loop light in the strain sensing system of the invention based on flight time detection-microwave phase detection
The structural block diagram of one embodiment of device；
Fig. 3 is the measurement range of one embodiment of the local strain sensing system of the invention based on flight time detection
Result figure；
Fig. 4 is the resolution ratio table of one embodiment of the local strain sensing system of the invention based on flight time detection
Levy result figure；
Fig. 5 is the structural block diagram of the long-range strain sensing system of the invention based on flight time detection；
Fig. 6 is the result figure of one embodiment of the long-range strain sensing system of the invention based on flight time detection.
Specific embodiment
With reference to the accompanying drawing, by specific embodiment, the present invention is further explained.
Embodiment one
In the present embodiment, strain sensing system detection range is less than 1km, for local strain sensing system.
As shown in Figure 1, the local strain sensing system based on flight time detection of the present embodiment includes: 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 exports 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 it is transmitted 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 is transmitted to again to be filled into proportional, integral feedback control
It sets, generates control signal, be transmitted to microwave source；Microwave source is adjusted in 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, is transmitted 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 is also transmitted to
Second optical fiber loop light-microwave phase detector；Second optical fiber loop light-microwave phase detector on the basis of microwave signal,
It obtains and strains related error signal, read by data acquisition device；Data acquisition device passes through error related with strain
Signal is delayed, to obtain the strain information at strain transducer.
In the present embodiment, pulse laser uses er-doped mode locking femto second optical fiber laser, repetition rate 250MHz, spectrum width
70nm；The score ratio 50:50 of fiber optic splitter；Two parts that fiber optic splitter is divided into, the power of every part are 18mW；Microwave source
Using voltage controlled crystal oscillator, the microwave of 8GHz is generated；The locking strip of proportional, integral feed back control system is wider than 100kHz；Strain passes
Sensor uses the fiber stretcher of 40.8m, applies the electric signal of 3kHz, 35mVrms as calibration signal；For greater than 1Hz's
High frequency strain, data acquisition device use Fourier spectrum analyzer, the low frequency less than 1Hz are strained, 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 include two multiply two couplers, first collimator, the first Faraday rotator, quarter-wave plate,
Second Faraday rotator, half wave plate, the second collimator, electrooptic modulator；The output of pulse laser multiplies as two
The input of two couplers, input of the output of microwave source as electrooptic modulator, two multiply the output of two couplers as light level
The input of weighing apparatus detector can get error signal from the output of photoelectricity balanced detector.
Fig. 3 and Fig. 4 is the measurement range result figure of the local strain transducer based on flight time detection 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；It can by Fig. 4
To find out, it is 18p ε/Hz at 1Hz that this system detection strain, which has very high resolution ratio,1/2, it is 1.9p ε/Hz at 3kHz1 /2。
Embodiment two
In the present embodiment, strain sensing system carries out remote probe, and detection range 1km or more is long-range strain sensing
System.
As shown in figure 5, the long-range strain sensing system based on flight time detection of the present embodiment includes: local end
Point, fiber optical circulator and distal portions；Wherein, local end 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 reflecting mirror, strain transducer and the second reflecting mirror；
The pulse laser output laser pulse sequence of local end part；Fiber annular is transmitted to through transmission fiber and dispersion compensating fiber
The first port of device is exported through second port to the second wavelength division multiplexer of distal portions；Second wavelength division multiplexer is by laser arteries and veins
It rushes sequence and is demultiplexing as two parts, respectively reference laser pulse train and exploring laser light pulse train；Reference laser pulse sequence
Column are transmitted to the first reflecting mirror 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 return of the second reflecting mirror, again passes by strain transducer, and light path changes, 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,
It is transmitted to the second port of optical fiber circulator, is exported by third port, is transmitted to local through transmission fiber and dispersion compensating fiber
First wavelength division multiplexer of end 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；Reference laser pulse train is after the amplification of the first fiber amplifier
It is transmitted 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 obtain reference laser pulse train and microwave
The phase error signal of signal；Phase error signal is transmitted to again into proportional, integral feed back control system, generates control signal,
It is transmitted to microwave source；Microwave source is adjusted in control signal, so that the microwave signal and reference laser pulse of microwave source output
Sequence synchronization；Exploring laser light pulse train is transmitted to the second optical fiber loop light-microwave phase after the amplification of 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 and strains related error signal, is read by data acquisition device；
Data acquisition device is delayed by error signal related with strain, to obtain the strain letter of strain transducer generation
Breath.
In the present embodiment, pulse laser uses er-doped mode locking femto second optical fiber laser, repetition rate 250MHz, spectrum width
70nm, power 5mW；Microwave source uses voltage controlled crystal oscillator, generates the microwave of 8GHz；The locking of proportional, integral feed back control system
Band is wider than 100kHz；Strain transducer uses the fiber stretcher of 40.8m；For being greater than the high frequency strain of 1Hz, data acquisition
Device uses Fourier spectrum analyzer, and the low frequency less than 1Hz is strained, and data acquisition device uses data collecting card；It passes
It loses fine using 1km single mode optical fiber；Dispersion compensating fiber is 100m；The first wave length section of first and second wavelength division multiplexers is
1550nm~1558nm, second wave length section are 1558nm~1566nm.
Fig. 6 is the strain sensing result figure of the long-range strain sensing system based on flight time detection of the present embodiment；By
Fig. 6, which can be seen that this system remote probe strain, has very high resolution ratio, is 80p ε/Hz at 1Hz1/2, it is at 3kHz
2.2pε/Hz1/2, while the factors such as optical fiber link temperature can be inhibited to influence measurement bring.
It is finally noted that the purpose for publicizing and implementing example is to help to further understand the present invention, but this field
Technical staff be understood that without departing from the spirit and scope of the invention and the appended claims, it is various replacement 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
Subject to the range that sharp claim defines.
Claims (10)
1. a kind of local strain sensing system based on flight time detection, which is characterized in that the local strain sensing system
It include: pulse laser, fiber optic splitter, the first optical fiber loop light-microwave phase detector, proportional, integral feedback control dress
It sets, 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 detector obtains the phase error signal of reference laser pulse train and microwave signal；Phase error signal is again
It is transmitted into proportional, integral feed back control system, generates control signal, be transmitted to microwave source；Signal is controlled to carry out microwave source
It adjusts, so that the microwave signal of microwave source output is synchronous with reference laser pulse train；Exploring laser light pulse train is through overstrain
Sensor is transmitted to the second optical fiber loop light-microwave phase detector, due to the strain at strain transducer, exploring laser light arteries and veins
The light path for rushing sequence changes, so that the flight delay of exploring laser light pulse train changes；With reference laser
The synchronous microwave signal of pulse train is also transmitted to the second optical fiber loop light-microwave phase detector；Second optical fiber loop light-micro-
Wave phase detector is obtained on the basis of microwave signal and strains related error signal, read by data acquisition device；Data
Acquisition device is delayed by analysis with related error signal is strained, to obtain the strain information at strain transducer；
The local strain sensing system is used for proximity detection, and distance is less than 1km.
2. local strain sensing system as described in claim 1, which is characterized in that the pulse laser, which uses, mixes bait mode locking
Femto second optical fiber laser, mix in bait mode locking picosecond optical fiber laser, solid pulse laser and semiconductor pulse laser one
Kind.
3. local strain sensing system as described in claim 1, which is characterized in that the microwave source uses voltage controlled crystal oscillator or Jie
Matter oscillator.
4. local strain sensing system as described in claim 1, which is characterized in that for being greater than the high frequency strain of 1Hz, data
Acquisition device uses Fourier spectrum analyzer, and the low frequency less than 1Hz is strained, and data acquisition device is acquired using data
Card.
5. a kind of long-range strain sensing system based on flight time detection, which is characterized in that the long-range strain sensing system
It include: local end part, fiber optical circulator and distal portions；Wherein, the local end 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 acquisition device；The distal portions include the second wavelength division multiplexer, the first reflecting mirror, answer
Become sensor and the second reflecting mirror；The pulse laser output laser pulse sequence of the local end part；Through transmission fiber and
Dispersion compensating fiber is transmitted to the first port of optical fiber circulator, exports 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 reflecting mirror through optical fiber, and the second wavelength division multiplexer is returned after reflection；It visits
It surveys laser pulse sequence and is transmitted to the return of the second reflecting mirror by strain transducer, again pass by strain transducer, light path occurs
Change, to change delay, returns to the second wavelength division multiplexer；Second wavelength division multiplexer is by reference laser pulse train and spy
It surveys laser pulse sequence and is multiplexed with light beam, be transmitted to the second port of optical fiber circulator, exported by third port, through transmitting light
Fine and dispersion compensating fiber is transmitted to the first wavelength division multiplexer of local end part；The first wavelength division multiplexer laser pulse sequence
Column are demultiplexing as two parts, respectively the exploring laser light pulse train of 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 the amplification of 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
It surveys device and obtains the phase error signal of reference laser pulse train and microwave signal；Phase error signal is transmitted to again into ratio-
Integral feedback control device generates control signal, is transmitted to microwave source；Microwave source is adjusted in control signal, so that microwave
The microwave signal of source output is synchronous with reference laser pulse train；Exploring laser light pulse train is after the amplification of the second fiber amplifier
It is transmitted 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 related with strain
Error signal is read by data acquisition device；Data acquisition device is delayed by analysis with related error signal is strained,
To obtain the strain information at strain transducer；The long-range strain sensing system be used for remote probe, remotely finger 1km with
On.
6. long-range strain sensing system as claimed in claim 5, which is characterized in that the pulse laser, which uses, mixes bait mode locking
Femto second optical fiber laser, mix in bait mode locking picosecond optical fiber laser, solid pulse laser and semiconductor pulse laser one
Kind.
7. long-range strain sensing system as claimed in claim 5, which is characterized in that the microwave source uses voltage controlled crystal oscillator or Jie
Matter oscillator.
8. long-range strain sensing system as claimed in claim 5, which is characterized in that described for being greater than the high frequency strain of 1Hz
Data acquisition device uses Fourier spectrum analyzer, and the low frequency less than 1Hz is strained, and the data acquisition device uses number
According to capture card.
9. a kind of local strain sensing method based on flight time detection, detection range are less than 1km, which is characterized in that described
Local strain sensing method the following steps are included:
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
Microwave signal 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 again into proportional, integral feed back control system, is generated control signal, is transmitted to microwave source；
Microwave source is adjusted in 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, is transmitted to the second optical fiber loop light-microwave phase detector, due to
The light path of strain at strain transducer, exploring laser light pulse train changes, so that exploring laser light pulse train
Flight delay changes；It is micro- to be also transmitted to the second optical fiber loop light-for the microwave signal synchronous with reference laser pulse train
Wave phase detector；
6) the second optical fiber loop light-microwave phase detector is obtained on the basis of microwave signal and is strained related error signal,
It is read by data acquisition device；
7) data acquisition device is delayed by analysis with related error signal is strained, to obtain at strain transducer
Strain information.
10. a kind of long-range strain sensing method based on flight time detection, detection range is 1km or more, which is characterized in that remote
Journey strain sensing method the following steps are included:
1) the pulse laser output laser pulse sequence of local end part；Light is transmitted to through transmission fiber and dispersion compensating fiber
The first port of fine circulator is exported through second port to the second wavelength division multiplexer of distal portions；
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 reflecting mirror through optical fiber, and the second wavelength division multiplexer is returned after reflection；
4) exploring laser light pulse train is transmitted to the return of the second reflecting mirror by strain transducer, again passes by strain transducer,
Due to strain, light path changes, so that pulse flight delay be made to change, 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 third port, is transmitted to local end part through transmission fiber and dispersion compensating fiber
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 detection after the amplification of the first fiber amplifier
Device, 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 the phase error signal of reference laser pulse train and microwave signal；
8) phase error signal is transmitted to again into proportional, integral feed back control system, is generated control signal, is transmitted to microwave source；
Microwave source is adjusted in 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 detection after the amplification of the second fiber amplifier
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 is obtained on the basis of microwave signal and is strained related error letter
Number, it is read by data acquisition device；
11) data acquisition device is delayed by analysis with related error signal is strained, to obtain at strain transducer
Strain information.
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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 |
| CN102175268A (en) * | 2011-01-29 | 2011-09-07 | 西南交通大学 | Quasi-distributed sensor network based on time division multiplex and matched optical fiber grating technology |
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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 |
| CN102175268A (en) * | 2011-01-29 | 2011-09-07 | 西南交通大学 | Quasi-distributed sensor network based on time division multiplex and matched optical fiber grating technology |
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