CN106199623B - A kind of femtosecond laser intermode beat frequency method range-measurement system - Google Patents
A kind of femtosecond laser intermode beat frequency method range-measurement system Download PDFInfo
- Publication number
- CN106199623B CN106199623B CN201610473590.9A CN201610473590A CN106199623B CN 106199623 B CN106199623 B CN 106199623B CN 201610473590 A CN201610473590 A CN 201610473590A CN 106199623 B CN106199623 B CN 106199623B
- Authority
- CN
- China
- Prior art keywords
- light
- frequency
- acousto
- amici prism
- femtosecond laser
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000005259 measurement Methods 0.000 title claims abstract description 73
- 238000000034 method Methods 0.000 title claims abstract description 44
- 230000035559 beat frequency Effects 0.000 title claims abstract description 18
- 239000000835 fiber Substances 0.000 claims abstract description 23
- 238000012545 processing Methods 0.000 claims abstract description 11
- 230000003287 optical effect Effects 0.000 claims description 12
- 238000012544 monitoring process Methods 0.000 claims description 11
- 238000012360 testing method Methods 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 6
- 230000000149 penetrating effect Effects 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 13
- 230000004044 response Effects 0.000 abstract description 2
- 239000004615 ingredient Substances 0.000 description 6
- 230000005622 photoelectricity Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 2
- 238000005305 interferometry Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 238000002366 time-of-flight method Methods 0.000 description 2
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- G01S17/34—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The present invention relates to a kind of femtosecond laser intermode beat frequency method range-measurement systems, it is characterized in that, the range-measurement system includes femtosecond laser frequency comb, acousto-optic modulator, the first Amici prism, the second Amici prism, the first mechanical shutter, the second mechanical shutter, the first speculum, the first fibre-coupled mirrors, the second fibre-coupled mirrors, beam expander, corner reflector, the first photodetector, the second photodetector and signal processing system.The present invention realizes synthetic wavelength using acousto-optic modulator, the range of femtosecond laser intermode beat frequency method is enlarged, cavity length is varied without in measurement process and adjusts femto-second laser repetition rate, since acousto-optic modulator is automatically controlled device, compared to the mechanical delay line for adjusting laser resonator cavity length, acousto-optic modulator controller architecture is simple, it is easy to operation, and the response device time is short, therefore single measurement required time can be greatly reduced, simplify measuring process, realizes that convenient quickly measures.
Description
Technical field
The present invention relates to a kind of femtosecond laser absolute distance measurement systems, especially with regard to a kind of femtosecond laser intermode beat frequency
Method range-measurement system.
Background technology
Traditional laser distance measurement method includes time-of-flight method, interferometry, Single wavelength phase method etc..Time-of-flight method passes through
Measure light turnaround time measurement target range between light source and target, since ray velocity is exceedingly fast, the shuttle flight of light
Time is shorter, and measurement accuracy is limited, causes the range accuracy of this method not high；The survey of matt wavelength magnitude may be implemented in interferometry
Accuracy of measurement, but non-fuzzy distance must also set up guide rail in wavelength magnitude, measurement process and carry out uninterrupted increment type measurement, no
It can realize absolute distance measurement；The amplitude that Single wavelength phase method carries out continuous laser radio band is modulated, by measuring light propagation
The phase delay that modulating wave generates in the process resolves distance, and the more long then range of modulation wavelength is bigger, but range accuracy reduces, on the contrary
The more short then precision of modulation wavelength is higher, but range is also smaller, therefore this method can not take into account wide range and high-precision.In mainframe
Ranging occasion needed for tool equipment, large aircraft, high-speed railway, civil engineering and satellites formation reaches micro- to finding range
Rice magnitude, the ranging technology that ranging range reaches km magnitude has larger demand, and above-mentioned three kinds of conventional laser distance measuring methods are equal
It is difficult to meet the needs of range and precision simultaneously.
With the development of laser technology, the appearance of femtosecond laser frequency comb light source is large scale high-precision absolute distance measurement
Bring breakthrough.Femtosecond laser is a kind of ultra-short pulse laser of pulse width in femtosecond magnitude, is a series of steady on frequency domain
Longitudinal mode spectral line that is fixed, being spacedly distributed, adjacent longitudinal mode spacing are known as repetition rate, abbreviation repetition, with frepIt indicates, repetition rate
Generally in the radio frequency band of tens to hundreds of MHz.Mutually beat intermode beats signal can be formed between each longitudinal mode of femtosecond laser, clap signal
Including frequency content be repetition rate positive integer times, can carry out multi-wavelength phase method using these different frequency contents
Ranging, low frequency long wavelength signals can be used for wide range bigness scale, and based on bigness scale result, the long signal of high-frequency short waves can be used for into one
Step improves measurement accuracy, it is possible thereby to realize high-precision and wide range simultaneously.Japanese research team first reported within 2000
Femtosecond laser frequency comb multi-wavelength interference method range-measurement system and experimental result.Since femtosecond laser repetition rate is tens to hundreds of
MHz, the minimum ingredient of intermode beat frequency signal intermediate frequency rate, i.e. frep, corresponding wavelength is that the non-fuzzy distance measured only arrives for several meters
Tens meters, if as reference without priori data, this method range is also only capable of reaching tens meters, still cannot meet many engineerings
Demand of the application scenario to km magnitude wide range.
To solve the above-mentioned problems, the method that the prior art proposes synthetic wavelength range extension, this method pass through change
Laser resonance cavity length carries out minor alteration to femtosecond laser repetition rate, changes front and back repetition rate and forms synthetic wavelength,
Phase method bigness scale is carried out first with synthetic wavelength, intermode beat frequency fado wavelength ranging is recycled to obtain high-precision.Due to testing
Synthetic wavelength can reach several kms to tens km magnitudes under precision, and program range also extends to km magnitude, i.e., simultaneously
Realize wide range and high-precision.But this method needs manual or automatically controlled adjusting femtosecond laser resonant cavity delay line length, relates to
And mechanical adjustment, regulating system structure is complex, long the time required to adjusting, long the time required to causing to measure, and is unfavorable for quickly
It measures in real time；And the stability of laser may be had an impact in adjustment process.In addition in certain commercial femtosecond laser frequencies
Rate, which is combed, does not have the function that wide range adjusts laser resonator in light source, therefore cannot achieve composite wave regular way yet and expand femtosecond
Laser intermode beat frequency method ranging range.
Invention content
In view of the above-mentioned problems, the object of the present invention is to provide one kind varying without femto-second laser repetition rate, it is not required to adjust
The mechanical delay line length in laser resonator is saved, measurement scheme is easy, small on laser stability influence, can realize quickly
The femtosecond laser intermode beat frequency method range-measurement system of measurement.
To achieve the above object, the present invention takes following technical scheme：A kind of femtosecond laser intermode beat frequency method range-measurement system,
It is characterized in that, the range-measurement system include femtosecond laser frequency comb, acousto-optic modulator, the first Amici prism, the second Amici prism,
First mechanical shutter, the second mechanical shutter, the first speculum, the first fibre-coupled mirrors, the second fibre-coupled mirrors, beam expander, angle
Speculum, the first photodetector, the second photodetector and signal processing system；The femtosecond laser frequency comb will be sent out
Frequency comb is emitted to the acousto-optic modulator；0 order diffraction light being modulated without the acousto-optic modulator is through several speculums
First Amici prism is emitted to after reflection, the frequency of 0 order diffraction light is identical as the light frequency of the femtosecond laser frequency comb；
The 1 order diffraction light through acousto-optic modulator modulation is reflected into the first light splitting rib with some modulation angle through a speculum
Mirror, 0 order diffraction light and 1 order diffraction light are divided into two-beam after closing light at first Amici prism, 0 order diffraction before closing light
The light path of light and 1 order diffraction light is identical, and the wherein light beam in two-beam is emitted to first fibre-coupled mirrors as fixation
The reference light of reception is passed through a fibre optical transmission to first photoelectricity by the reference arm light path of length, first fibre-coupled mirrors
Detector；Another beam light emitting in two-beam is to second Amici prism, through a branch of of second Amici prism outgoing
Light is emitted to monitoring arm light path of first speculum as regular length through first mechanical shutter, anti-through described first
The monitoring light for penetrating mirror reflection returns to second Amici prism according to original optical path；Another beam being emitted through second Amici prism
Light is emitted to the corner reflector conduct being fixed on object under test after second mechanical shutter and beam expander and waits for
Ranging from measuring arm, the measurement light through corner reflector reflection returns to second Amici prism according to original optical path, described
Second Amici prism will monitor light or measure light by second fibre-coupled mirrors through a fibre optical transmission to second photoelectricity
Detector；The signal detected is sent to the signal processing system by first photodetector and the second photodetector
System.
Preferably, the signal processing system includes two signal sources, four low-pass filters, two gain amplifiers, a lock
Phase amplifier, a computer and a shutter controller；The output end of first photodetector and the second photodetector point
Not connecting the input terminal of a frequency mixer, another input terminals of two frequency mixers is all connected with first signal source, and described first
Signal source output terminal connects the computer, and the output end of two frequency mixers amplifies through the first low-pass filter, gain respectively
Device and the second low-pass filter are connected in parallel the input terminal of the lock-in amplifier, and the output end of the lock-in amplifier is through a number
The computer is connected according to harvester, it is fast that the computer also controls first machinery respectively by the shutter controller
The opening and closing of door and the second mechanical shutter；The input terminal in the second signal source connects the computer, second letter
The output end in number source connects the acousto-optic modulator.
The invention adopts the above technical scheme, which has the following advantages：1, the present invention uses acousto-optic modulator shift frequency
It realizes that synthetic wavelength measures, have no need to change femto-second laser repetition rate and adjusts the mechanical delay line length in laser resonator
Degree, light path and circuit structure are simple, and femto-second laser only needs locking repetition rate in system, are not required to locking carrier envelope offset frequency
Rate, it is low to the control difficulty of frequency comb, it may be implemented quickly to measure, can reach within 1s the time required to single measurement.2, this hair
It is bright that synthetic wavelength is realized by acousto-optic modulator, the range of femtosecond laser intermode beat frequency method is enlarged, in measurement process not
Cavity length need to be changed and adjust laser repetition rate；Since acousto-optic modulator is automatically controlled device, compared to adjusting, laser is humorous
Shake the mechanical delay line of cavity length, and acousto-optic modulator controller architecture is simple, easy to operation, and the response device time is short, therefore
The time required to single measurement can be greatly reduced, simplify measuring process, realizes that convenient quickly measures.3, due to circuit system asymmetry
Drift can cause phase measurement to be drifted about, and the present invention is disappeared using monitoring arm light path cooperative mechanical shutter alternating handover measurement mode
Except phase measurement is drifted about, high-precision phase measurement may be implemented, improve measurement accuracy.4, the present invention utilizes electric heterodyne method
High-frequency oscillation signal is reduced to low frequency signal, the phase of high-acruracy survey high-frequency oscillation signal realizes ranging phase method；In addition,
Big ranging range is obtained using synthetic wavelength method, the absolute distance for realizing range up to km magnitude, precision up to micron dimension is surveyed
Amount.The present invention can be widely applied in femtosecond laser absolute distance measurement.
Description of the drawings
Fig. 1 is the range-measurement system structural schematic diagram of the present invention；
Fig. 2 is the signal processing system principle schematic of the present invention.
Specific implementation mode
Come to carry out detailed description to the present invention below in conjunction with attached drawing.It should be appreciated, however, that attached drawing has been provided only more
Understand the present invention well, they should not be interpreted as limitation of the present invention.
As shown in Figure 1, femtosecond laser intermode beat frequency method range-measurement system provided by the invention, including femtosecond laser frequency comb L,
Collimation lens N, acousto-optic modulator AOM, the first Amici prism BS1, the second Amici prism BS2, the first mechanical shutter S1, the second machine
Tool shutter S2, speculum M1, the first fibre-coupled mirrors D1, the second fibre-coupled mirrors D2, beam expander K, corner reflector C, the first photoelectricity
Detector PD1, the second photoelectric detector PD2And signal processing system.
The centre wavelength sent out is 1560nm by femtosecond laser frequency comb L, repetition rate be 56.27MHz (as example,
It is without being limited thereto) frequency comb be transferred to after collimation lens N via an optical fiber and be emitted to acousto-optic modulator AOM；
It is sent out after the reflection of several speculum (not shown)s without the 0 order diffraction light that acousto-optic modulator AOM is modulated
It is mapped to the first Amici prism BS1, the frequency of 0 order diffraction light is identical as the light frequency of femtosecond laser frequency comb；
The 1 order diffraction light modulated after acousto-optic modulator AOM is reflected into first point with some modulation angle through a speculum
Light prism BS1, 0 order diffraction light and 1 order diffraction light are in the first Amici prism BS1It is divided into two-beam after place's closing light (to need to ensure closing light
The light path of 0 order diffraction light and 1 order diffraction light before is identical, and specifically used process can carry out light by using several speculums
The adjusting of journey, details are not described herein), wherein light beam is through the first fibre-coupled mirrors D1As the reference arm light path of regular length,
First fibre-coupled mirrors D1Reference light is passed through into a fibre optical transmission to the first photoelectric detector PD1, another beam light emitting is to second point
Light prism BS2, through the second Amici prism BS2The light beam of outgoing is through the first mechanical shutter S1It is emitted to speculum M1As fixation
The monitoring arm light path of length, through speculum M1The monitoring light of reflection returns to the second Amici prism BS according to original optical path2；Through second point
Light prism BS2The another light beam of outgoing is through the second mechanical shutter S2It is emitted to beam expander K, the light emitting after beam expander K is expanded arrives
Measuring arms of the corner reflector C as testing distance being fixed on object under test, the measurement light through corner reflector C reflections are pressed
The second Amici prism BS is returned according to original optical path2, the second Amici prism BS2Light will be monitored or measure light and pass through the second fibre-coupled mirrors
D2Through fibre optical transmission to the second photoelectric detector PD2, the first photoelectric detector PD1With the second photoelectric detector PD2By what is detected
Signal is sent to signal processing system.
As shown in Fig. 2, signal processing system includes two signal sources, two frequency mixers, four low-pass filters, two gains amplification
Device, a lock-in amplifier, a computer and a shutter controller；First photoelectric detector PD1With the second photoelectric detector PD2's
Output end is separately connected an input terminal of a frequency mixer HP, and another input terminal of two frequency mixer HP is all connected with the first signal source SN1,
The output end of first signal source SN1 connects computer, and the frequency of the first signal source SN1 output signals is controlled by computer
System, the output end of two frequency mixer HP is respectively through the first low-pass filter LB1, gain amplifier FD and the second low-pass filter LB2
It is connected in parallel the input terminal of lock-in amplifier RS, the output end of lock-in amplifier RS connects computer through a data acquisition device,
Computer carries out data acquisition to lock-in amplifier RS and parameter controls.Computer can also respectively be controlled by shutter controller
Make the first mechanical shutter S1With the second mechanical shutter S2Opening and closing；The input terminal of second signal source SN2 connects computer,
The output end of second signal source SN2 connects acousto-optic modulator AOM, output or pass of the computer by control second signal source SN2
It closes to start or close acousto-optic modulator AOM.
The femtosecond laser intermode beat frequency method range-measurement system of the present invention is in distance measurement process, the first mechanical shutter S1With
Two mechanical shutter S2It quickly alternately opens, measures the phase difference of monitoring arm and reference arm respectivelyMeasuring arm and reference arm
Phase differenceSince reference arm and monitoring arm are regular length, and measuring arm and monitoring arm share measuring circuit,Variation can reflect due to the first photoelectric detector PD1With the second photoelectric detector PD2And electricity in connection
Phase difference measurements drift or shake caused by road.It, can be with since circuit drift speed is far below mechanical shutter switch speed
ThinkWithMeasurement be for circuit drift while, you can takeMake
For phase difference measurements, to eliminate the influence of circuit drift or jitter error for distance measurement result.
Femtosecond laser intermode beat frequency method range-measurement system using the present invention measures process to testing distance can be divided into two
Step：
1, computer starting second signal source SN2 drives acousto-optic modulator AOM, 0 order diffraction light and 1 order diffraction actinic light,
First photoelectric detector PD1With the second photoelectric detector PD2The electric signal of output removes mfrepFurther include two outside intermode beat frequency ingredient
Ingredient ± f obtained by the mutual beat of order diffraction lightAOM+mfrep, as the suitable f of selectionAOMWhen, it will there are one be much smaller than in these ingredients
frepLow-frequency component fs, such as frepF is taken when=56.27MHzAOM=168.61MHz, then the first photoelectric detector PD1With the second light
Electric explorer PD2There is f in output signalsThe low-frequency component of=0.2MHz, the frequency content corresponding wavelength are much larger than frequency comb fundamental frequency
Wavelength.Low-pass filter filters out and detects phase difference, the range measurement knot of acquisition by lock-in amplifier after this low frequency composition signal
Fruit is as bigness scale result.
2, computer control closes second signal source SN2, acousto-optic modulator AOM and does not generate 1 order diffraction light.Two photoelectricity at this time
The electric signal of detector output includes to swash frequency comb intermode Beat Signal fundamental wave and several higher harmonic component mfrep, the frequency spectrum upper limit
It is limited by photodetector bandwidth.Femtosecond laser intermode beats signal component frequency is high, and frequency interval is small, it is difficult to pass through low-pass filtering
Device directly filters out a certain ingredient and measures phase difference, it is therefore desirable to use heterodyne measurement method, measure mfrepHarmonic components
When phase difference, it is mf to adopt the first signal source of computerizeing control and generate frequencyrepThe sinusoidal signal of+Δ f, respectively with two photoelectricity
The output signal of detector is mixed, and mixer output signal will contain Δ f low-frequency components.It is defeated when two frequency mixer of the first signal source pair
Enter signal phase it is equal when, two mixer output signals remain the phase information of two photo detector signals, can pass through
Low-pass filter filters out and detects phase difference by lock-in amplifier.
Below by the measurement of the specific embodiment femtosecond laser intermode beat frequency method range-measurement system that the present invention will be described in detail
Journey：
1, it is f to add frequency on acousto-optic modulator AOMAOMModulated signal, generate synthetic wavelength λs=c/nfs, measure this
The phase difference of reference light and measurement light, obtains bigness scale result D ' under wavelength, and detailed process is：
Computer control starts second signal source SN2 and drives acousto-optic modulator AOM, has suitably in acousto-optic modulator AOM
Frequency is fAOMWhen signal modulation, there are one be much smaller than f in the frequency content of two photodetector electric signalsrepLow-frequency component
fs, the corresponding wavelength X of the frequency signals=c/nfsReferred to as synthetic wavelength is D ' using synthetic wavelength ranging rangemax=λs/2。
Since f can be adjustedAOMMake fs<<frep, therefore this ranging range is very big.F is filtered out using low-pass filtersSignal simultaneously uses locking phase
Amplifier measures phase difference, and it is D ' that testing distance is measured in synthetic wavelength range ability, as coarse range measuring result.Theoretically
As long as fsClose to zero, λsIt can approach infinity, you can obtain great ranging range.But in measurement later, in order to correct
Calculate the fundamental frequency wavelength number complete cycle N for including in testing distance1, the measured deviation of above-mentioned D ' should have the upper limit.And the λ usedsMore
Greatly, D ' measurement errors are bigger, therefore are limited to measurement error, range D 'max=λs/ 2 can not possibly infinitely expand, but general reality
It tests under precision and sufficiently achieves km magnitude.
2, the modulated signal for closing AOM on acousto-optic modulator makes only 0 order diffraction light be emitted, and adjusts the first signal source SN1
Output, make the signal and f=frepFundamental component generate low frequency heterodyne signal, measure fundamental frequency wavelength under reference light and measurement
The phase difference of light obtains reference light and measurement light phase level difference measurements under fundamental frequency wavelengthAnd by D ' andDetermine base
Frequency distance measurement result D1, specific measuring principle and process are：
Use in intermode Beat Signal frequency for mfrepThe ingredient of (m is positive integer) carries out interferometric phase method ranging, measures
Phase difference between reference signal and measuring signal isThen absolute distance measurement result is：
In formula, c is the light velocity in vacuum, and n is air refraction, can be according to the correlation theory of air refraction by environmental parameter
It determines, λ=c/nfrepTo swash frequency comb fundamental frequency wavelength.The phase difference measured due to instrument within the scope of 0~2 π, deposit by distance measurement result
The natural number N in fuzzy ranges, formula (1)mIndicate the 2 π number of cycles of phase difference that instrument can not determine.
After locking repetition rate by atomic clock, frequency comb repetition rate shake δ f are swashedrep<1mHz considers instrument error
With measurement random error, the measurement error of phase differenceIn 0.01 ° of order of magnitude, repetition rate relative error is surveyed much smaller than phase difference
Relative error is measured, phase difference measurement is main source of error, and can obtain range measurement error according to formula (1) is
The sharp frequency comb intermode difference frequency that i.e. ranging uses is higher, and range error is smaller, and precision is higher.Consider range and essence
Degree first uses f=f when measuringrepFundamental component carry out wide range bigness scale, at this time according to synthetic wavelength bigness scale result D ' and base
The lower phase difference measurements of frequencyMeasurement result determines N1, i.e.,：
Then fundamental frequency distance measurement result D1It is represented by：
3, the output for adjusting the first signal source SN1, makes the signal and f=mfrepA certain radio-frequency component generate low frequency heterodyne
Signal, wherein choosing for positive integer m can be determined according to the photodetector bandwidth upper limit used, measure reference light under the wavelength
With the phase difference for measuring light, phase difference measurements are obtainedAnd by D1WithMeasurement result determines Nm, and then determine and survey
Away from result Dm, as final measurement, detailed process be：
Use f=mf insteadrepHigher hamonic wave accurately measured, Integer NmBy phase differenceMeasurement result and D1It determines：
At this time by the higher measurement result of formula (1) attainable accuracy：
D is substituted into further according to (3) formula1Measurement result can obtain range measurements finally：
In above-mentioned each pacing amount, monitoring arm light path and double-shutter switching can be used to eliminate circuit drift error, specifically
Principle and data processing method are being mentioned above, and details are not described herein；In addition, multiple survey can be used in above-mentioned each pacing amount
The mode of average value is measured, the random error in measuring is reduced.
The various embodiments described above are merely to illustrate the present invention, wherein the structure of each component, connection type and manufacture craft etc. are all
It can be varied from, every equivalents carried out based on the technical solution of the present invention and improvement should not exclude
Except protection scope of the present invention.
Claims (2)
1. a kind of femtosecond laser intermode beat frequency method range-measurement system, which is characterized in that the range-measurement system include femtosecond laser frequency comb,
Acousto-optic modulator, the first Amici prism, the second Amici prism, the first mechanical shutter, the second mechanical shutter, the first speculum,
One fibre-coupled mirrors, the second fibre-coupled mirrors, beam expander, corner reflector, the first photodetector, the second photodetector and letter
Number processing system；
The frequency comb sent out is emitted to the acousto-optic modulator by the femtosecond laser frequency comb；Without the acousto-optic modulator into
0 order diffraction light of row modulation is emitted to first Amici prism, the frequency of 0 order diffraction light and institute after the reflection of several speculums
The light frequency for stating femtosecond laser frequency comb is identical；
The 1 order diffraction light through acousto-optic modulator modulation is reflected into first light splitting with some modulation angle through a speculum
Prism, 0 order diffraction light and 1 order diffraction light are divided into two-beam after closing light at first Amici prism, and 0 before closing light grade is spread out
The light path for penetrating light and 1 order diffraction light is identical, and the wherein light beam in two-beam is emitted to first fibre-coupled mirrors as solid
The reference light of reception is passed through a fibre optical transmission to first light by the reference arm light path of measured length, first fibre-coupled mirrors
Electric explorer；Another beam light emitting in two-beam is to second Amici prism, one be emitted through second Amici prism
First mechanical shutter described in Shu Guangjing is emitted to monitoring arm light path of first speculum as regular length, through described first
The monitoring light of speculum reflection returns to second Amici prism according to original optical path；Through the another of second Amici prism outgoing
The corner reflector conduct being fixed on object under test is emitted to after second mechanical shutter and beam expander described in Shu Guangjing
The measuring arm of testing distance, the measurement light through corner reflector reflection return to second Amici prism, institute according to original optical path
Light will be monitored or measure light by second fibre-coupled mirrors through a fibre optical transmission to second light by stating the second Amici prism
Electric explorer；The signal detected is sent to the signal processing system by first photodetector and the second photodetector
System.
2. a kind of femtosecond laser intermode beat frequency method range-measurement system as described in claim 1, which is characterized in that the signal processing
System includes two signal sources, four low-pass filters, two gain amplifiers, a lock-in amplifier, a computer and a fast gate
Device processed；
The output end of first photodetector connects the input terminal of the first frequency mixer, the output of second photodetector
End connection the second frequency mixer input terminal, first frequency mixer, second frequency mixer another input terminal be all connected with first
Signal source, the first signal source input terminal connect the computer, and the output end of first frequency mixer is through the first low pass filtered
Wave device, the first gain amplifier and the second low-pass filter connect the input terminal of the lock-in amplifier, second frequency mixer
Output end connect the defeated of the lock-in amplifier through third low-pass filter, the second gain amplifier and the 4th low-pass filter
Enter end, the output end of the lock-in amplifier connects the computer through a data acquisition device, and the computer also passes through institute
State the opening and closing that shutter controller controls first mechanical shutter and the second mechanical shutter respectively；Second signal source it is defeated
Enter end and connect the computer, the output end in the second signal source connects the acousto-optic modulator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610473590.9A CN106199623B (en) | 2016-06-24 | 2016-06-24 | A kind of femtosecond laser intermode beat frequency method range-measurement system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610473590.9A CN106199623B (en) | 2016-06-24 | 2016-06-24 | A kind of femtosecond laser intermode beat frequency method range-measurement system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106199623A CN106199623A (en) | 2016-12-07 |
| CN106199623B true CN106199623B (en) | 2018-08-03 |
Family
ID=57461027
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610473590.9A Active CN106199623B (en) | 2016-06-24 | 2016-06-24 | A kind of femtosecond laser intermode beat frequency method range-measurement system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106199623B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108732580A (en) * | 2018-05-30 | 2018-11-02 | 浙江省计量科学研究院 | A kind of absolute distance measurement system and measurement method based on phase method Yu composite wave regular way |
| CN112255640B (en) * | 2020-09-11 | 2023-11-10 | 北京空间机电研究所 | Variable-frequency differential laser interference ranging device capable of adaptively adjusting light path |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101446687B (en) * | 2007-11-28 | 2010-07-07 | 中国科学院工程热物理研究所 | Collinear femto-second laser polarized pump detecting system |
| CN103197322B (en) * | 2013-04-10 | 2015-02-18 | 清华大学 | Ranging method and ranging system of femtosecond laser frequency comb synthesis wave interference |
| KR101448831B1 (en) * | 2013-04-16 | 2014-10-16 | 국방과학연구소 | Distance measuring apparatus using phase-locked synthetic wavelength interferometer based on femtosecond laser |
| CN103364775B (en) * | 2013-06-25 | 2015-03-04 | 清华大学 | Optical frequency comb calibration-based dual-color laser scanning absolute distance measuring device and method |
| CN103837077B (en) * | 2014-03-21 | 2017-01-25 | 清华大学 | Composite wave interferometry ranging distance system with two femtosecond laser frequency combs |
-
2016
- 2016-06-24 CN CN201610473590.9A patent/CN106199623B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN106199623A (en) | 2016-12-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8078060B2 (en) | Optical synchronization system for femtosecond X-ray sources | |
| Zou et al. | Microwave frequency measurement based on optical power monitoring using a complementary optical filter pair | |
| JP5425870B2 (en) | Remote clock synchronization | |
| CN104316186A (en) | Spectral measurement method based on optical frequency combs | |
| CN102901616B (en) | Method and equipment for measuring laser line width | |
| JP2005124192A (en) | Method and system for synchronizing operation characteristic of variable wavelength device to wavelength of local oscillator signal | |
| US11515994B2 (en) | Synchronizer and synchronizing transfer over an optical link | |
| CN114035174B (en) | Dual-channel dual-chirp linear frequency modulation continuous wave laser radar method and device | |
| US6788410B1 (en) | Delay time measurement apparatus for optical element | |
| CN111983628B (en) | Speed and distance measuring system based on monolithic integrated linear frequency modulation dual-frequency DFB laser | |
| CN103855599A (en) | Method for achieving laser frequency-offset-lock through scanning confocal cavity F-P interferometer | |
| CN103809166B (en) | A kind of Michelson interference type spectral filter resonant frequency locking device and method | |
| CN106199623B (en) | A kind of femtosecond laser intermode beat frequency method range-measurement system | |
| CN113823986B (en) | Photo-induced microwave device | |
| CN114047521B (en) | Optical frequency comb detection system | |
| CN109541621B (en) | Vibration compensation method of frequency scanning interference absolute ranging system | |
| CN104049248A (en) | Superheterodyne and heterodyne combined type optical-aliasing-resistance laser ranging device and method | |
| CN104155642A (en) | Traceable synchronous measurement ruler-based mixed double-light source laser range finding device and method | |
| CN112362173B (en) | Laser wavelength measuring device and method based on difference frequency double combs | |
| KR101448831B1 (en) | Distance measuring apparatus using phase-locked synthetic wavelength interferometer based on femtosecond laser | |
| WO2022230217A1 (en) | Optical frequency comb generator control device | |
| CN108732580A (en) | A kind of absolute distance measurement system and measurement method based on phase method Yu composite wave regular way | |
| Calonico et al. | Optical frequency transfer with a 1284 km coherent fiber link | |
| Shao et al. | A microwave photonic phase detector based on a dual-polarization dual-drive Mach-Zehnder modulator | |
| Yang et al. | Long-distance measurement applying two high-stability and synchronous wavelengths |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |