CN208547463U - Device for evaluating time domain stability of high-power optical fiber laser system - Google Patents
Device for evaluating time domain stability of high-power optical fiber laser system Download PDFInfo
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Abstract
A device for evaluating high-power optical fiber laser system time domain stability, the high-power optical fiber laser system to be measured output laser center wavelength is lambda1The Raman Stokes frequency shift quantity corresponding to the matrix material of the energy transmission optical fiber is delta lambdaRWavelength tunable ultra-low noise fiber laser with output laser center wavelength lambda2＝λ1+ΔλR(ii) a The laser output by the high-power optical fiber laser system to be tested and the wavelength-tunable ultra-low noise optical fiber laser are synthesized into a beam by a wavelength division multiplexer, and the beam is input into an energy transmission optical fiberThe laser beam output by the optical fiber is collimated by the collimator and then is divided into two beams through the band-pass filter, wherein the two beams respectively have the central wavelength of lambda2The central wavelength of the Raman amplified laser and the residual is lambda1Wherein the Raman-amplified laser is injected into the power meter with a residual center wavelength of λ1Is injected into the waste light collector. Utilize the utility model discloses evaluation high power fiber laser system time domain stability can avoid the bandwidth among the traditional approach problem such as limited, the system is with high costs.
Description
Technical field
The utility model belongs to High-power Laser Technologies field, evaluates Gao Gong based on pure optical detecting method more particularly to one kind
The device of rate fiber laser system time-domain stability.
Background technique
High power optical fibre laser system time-domain stability is probed into for Fibre Optical Sensor, optical-fibre communications, gravitational wave detection, non-thread
Property the fields such as optical fiber optics, large-power optical fiber laser system there is important scientific meaning and engineering value.
Specifically, in fields such as Fibre Optical Sensor, optical-fibre communications, gravitational wave detections, fiber laser system time-domain stability
Directly determine sensing, communication and the accuracy and sensitivity of detection.In nonlinear fiber optics application field, fiber laser system
Time-domain stability directly determines the nonlinear effects such as stimulated Brillouin scattering, stimulated Raman scattering, the Self-phase modulation of system
Kinetic characteristics.In large-power optical fiber laser field, time-domain stability directly determines the Amplified Spontaneous spoke of optical fiber amplification system
It penetrates, the nonlinear effects threshold property such as stimulated Brillouin scattering, the unstable, stimulated Raman scattering of thermotropic mode.It is above-mentioned non-linear
Threshold property directly determines the power ascension potentiality of fiber laser system.
Conventional method directly passes through the time-domain stability that photodetection means detected and evaluated high power optical fibre laser system.
This method can intuitively react distribution character of the output laser on different time scales, and then by Annual distribution characteristic to laser
Time-domain stability is analyzed.However, this method depends critically upon sensitive detection parts and photoelectric signal processor (such as oscillograph)
Responsive bandwidth.It probes into scale with laser system time-domain stability further to develop to microcosmicization, photodetection and processing mould
The bandwidth of block can seriously restrict the evaluation of seed time-domain stability superiority and inferiority.In addition, high bandwidth photodetection processing module exist at
This high deficiency.Compared with Traditional photovoltaic detection, pure optical detection diagnosis has responsive bandwidth height, fast response time etc. special
Advantage.
Therefore, designing has with the device of pure optical detecting method evaluation high power optical fibre laser system time-domain stability
Important scientific meaning and urgent reality need.
Utility model content
In view of the defects existing in the prior art, the utility model provides a kind of for when evaluating high power optical fibre laser system
The device of domain stability, provided device are to evaluate high power optical fibre laser system time-domain stability based on pure optical detecting method
The device of property, can to avoid Bandwidth-Constrained present in Traditional photovoltaic detection method, system cost is expensive the problems such as.
To realize the above-mentioned technical purpose, the technical solution of the utility model is:
For evaluating the device of high power optical fibre laser system time-domain stability, including high power optical fibre laser system to be measured
System, tunable wave length ultra-low noise optical fiber laser, wavelength division multiplexer, energy-transmission optic fibre, collimator, bandpass filter, power meter,
Useless light collector；
Its output laser center wavelength of the high power optical fibre laser system to be measured is λ1, the tunable wave length super-low noise
Its output laser center wavelength of acousto-optic fibre laser is λ2, Raman Stokes shift corresponding to its host material of energy-transmission optic fibre
Amount is Δ λR, wherein tunable wave length ultra-low noise optical fiber laser its export laser center wavelength λ2=λ1+ΔλR；
The high power optical fibre laser system to be measured and the laser of tunable wave length ultra-low noise optical fiber laser output are logical
It crosses wavelength division multiplexer and synthesizes beam of laser output, the laser beam after closing beam is injected into energy-transmission optic fibre, exports through energy-transmission optic fibre
Laser beam collimator collimate output, the laser beam exported from collimator is by being divided into two bundles in respectively after bandpass filter
The a length of λ of cardiac wave2Raman amplifiction laser and remaining central wavelength be λ1Laser, wherein central wavelength be λ2Raman amplifiction
Laser is injected into power meter, and remaining central wavelength is λ1Laser be injected into useless light collector.
In the utility model, that is, above-mentioned device for evaluating high power optical fibre laser system time-domain stability, Gao Gong to be measured
The laser of rate fiber laser system output serves as pumping laser, and the laser of tunable ultra-low noise optical fiber laser output serves as letter
Number laser, energy-transmission optic fibre provide Raman gain, in this way the Raman fiber laser amplifier structure of one forward pumping of composition.
The utility model evaluates the basic principle of high power optical fibre laser system time-domain stability with pure optical detecting method
It is as follows: to be λ by analysis center's wavelength2Raman amplifiction laser-conversion efficiency and central wavelength be λ1Pumping laser (height to be measured
The laser of fiber optic power laser system output) dependence between time-domain stability, pass through the defeated of measurement Raman amplifiction laser
Power out, and then the Raman amplifiction that Raman light conversion efficiency is calculated, and is ideally calculated with the fluctuating of no time domain
Laser power and Raman light conversion efficiency compare, that is, the time-domain stability of high power optical fibre laser system to be measured can be evaluated.
Specifically, one kind is provided and is commented for evaluating the device of high power optical fibre laser system time-domain stability based on above-mentioned
The method of valence high power optical fibre laser system time-domain stability, comprising the following steps:
(1) power and central wavelength lambda of high power optical fibre laser system output laser to be measured are measured1。
(2) determine the energy-transmission optic fibre used in device for evaluating high power optical fibre laser system time-domain stability and
Raman Stokes shift amount Δ λ corresponding to its host material of its energy-transmission optic fibreR。
(3) central wavelength lambda of tunable wave length ultra-low noise optical fiber laser output laser is determined2, λ2=λ1+ΔλR。
(4) output power of measurement tunable wave length ultra-low noise optical fiber laser output laser.
(5) core size and length of energy-transmission optic fibre are determined；And it calculates and rises and falls ideally Raman amplifiction without time domain
Laser power and Raman light conversion efficiency.
Energy-transmission optic fibre core size, the determination method of length and ideally without time domain rise and fall when Raman amplifiction laser function
The process that rate and Raman light conversion efficiency calculate is as described below:
Raman amplifiction process in forward pumping Raman fiber laser amplifier structure comprising pumping laser time domain specification passes through
The description of forward direction coupled amplitude equation, as described below:
Wherein: EpAnd EsRespectively represent the light field of pumping laser and signal laser, νgpAnd νgsRespectively represent pumping laser and
The group velocity of signal laser, β2pAnd β2sRespectively represent the group velocity dispersion coefficient of pumping laser and signal laser, αpAnd αsRespectively
Represent the loss factor of pumping laser and signal laser, δRFor variations in refractive index caused by Raman, fRIt is delay Raman response to non-
The decimal contribution linearly planned, gpAnd gsRespectively indicate the Raman gain coefficienct of pumping laser and signal laser；γpAnd γsRespectively
The Kerr coefficient of pumping laser and signal laser is represented, is indicated are as follows:
γp=2 π n2/λ1Aeff
γs=2 π n2/λ2Aeff (2)
Wherein, n2For nonlinear refractive index, AeffFor the effective core area of energy-transmission optic fibre.AeffWith energy-transmission optic fibre fibre core half
Dependence between diameter (a) indicates are as follows:
Aeff=Γ π a2 (3)
Wherein, Γ is relative scale coefficient, and general value is between 0.8~1.
The light field E of pumping laser and signal laserpAnd EsMeet between pump laser power and signal laser power:
Wherein: z is along the distance parameter of the length direction of energy-transmission optic fibre, and z is [0, L], indicates to pass energy light as z=0
Fine input terminal, when z=L, indicate the output end of energy-transmission optic fibre.dσFor along the effective core area A of energy-transmission optic fibreeffIntegral,
Referring to formula (3), it is directly related with energy-transmission optic fibre fiber core radius (a).
If signal laser (laser of i.e. tunable ultra-low noise optical fiber laser output) power of injection is Ps(0), it infuses
Pumping laser (laser of the high power optical fibre laser system output i.e. to be measured) power entered is Pp(0), using formula (1)-(4),
Can be calculated high power optical fibre laser system to be measured no time domain rise and fall ideally when Raman amplifiction laser power edge
The distribution P of energy-transmission optic fibre longitudinal directions(z).In conjunction with formula (1)~(4), the fiber core radius a and fiber lengths of energy-transmission optic fibre, energy are selected
Enough so that the pumping laser of high power optical fibre laser system to be measured output and the output of tunable wave length ultra-low noise optical fiber laser
Signal laser being capable of effective Raman amplifiction and Raman conversion in energy-transmission optic fibre.
If the fiber lengths of energy-transmission optic fibre are L, then z=L, P are enabledsIt (L) is to pass through Raman amplifiction rear center wavelength for λ2's
The output power of laser.Therefore, Raman when high power optical fibre laser system to be measured ideally rises and falls without time domain converts effect
Rate ηs1It may be expressed as:
(6) it by the device for evaluating high power optical fibre laser system time-domain stability, is obtained using power meter measurement
Central wavelength is λ under actual conditions2Raman amplifiction laser output power Pse(L), and then actual Raman light is calculated
Transfer efficiency (ηs2)；ηs2Specific formula for calculation it is as follows:
It (7) is λ by the central wavelength that actual measurement obtains in step (6)2Raman amplifiction laser power Pse(L) and step
(5) what is be calculated in rises and falls ideally Raman amplifiction laser power power P without time domains(L) ratio operation is done, if the ratio
Value is R1；Actual Raman light efficiency eta will be calculated in step (6)s2It is risen with what is be calculated in step (5) without time domain
The Raman light efficiency eta of volt ideallys2Ratio operation is done, if ratio is R2；Use R1Or R2Directly evaluate Gao Gong to be measured
The time-domain stability of rate fiber laser system.
The utility model can both use R1The time-domain stability of high power optical fibre laser system to be measured is directly evaluated, it can also be with
Use R2Directly evaluate the time-domain stability of high power optical fibre laser system to be measured.Specifically, ratio R1It is bigger, high power to be measured
The time-domain stability of fiber laser system is poorer；Likewise, ratio R2Bigger, the time domain of high power optical fibre laser system to be measured is steady
It is qualitative poorer.
High power optical fibre laser system type to be measured described in the utility model is unlimited, exports laser center wavelength not
Limit, can be output wavelength covering ytterbium ion emission spectra wave band (1um wave band) mixes ytterbium high power optical fibre laser system, output
Wavelength cover erbium ion emission spectra wave band (1.55 um wave band) er-doped high power optical fibre laser system, output wavelength covering thulium/
Holmium ion emission spectra wave band (2um wave band) mixes thulium/holmium high power optical fibre laser system, is also possible to output wavelength and covers other
The high power optical fibre laser system of special Doped ions emission spectra wave band；High power optical fibre laser system implementations to be measured are not
Limit can be direct high-power oscillator, high power super-fluorescence light source, the random fiber laser system of high power or be based on main oscillations
The high power optical fibre laser system that power amplification structure is realized；High power optical fibre laser system line width to be measured is unlimited, can be list
Frequently, narrow linewidth or general wide range high power optical fibre laser system.
Tunable wave length ultra-low noise optical fiber laser described in the utility model be generally single frequency optical fiber laser or
The narrow cable and wide optical fiber laser that phase-modulation generates is applied to single frequency optical fiber laser.The implementation of single frequency optical fiber laser is not
Limit, can be distributed feedback laser, Distributed Bragg Reflection laser, non-planar ring oscillator, single-frequency ring light
Fibre laser is also possible to the laser light source that single-frequency semiconductor laser passes through fiber coupling output.Tunable wave length super-low noise
Acousto-optic fibre laser wavelength tuning range is determined by the launch wavelength of high power optical fibre laser system to be measured.If high power light to be measured
The central wavelength that fiber laser system exports laser is λ1, its corresponding Raman Stokes shift amount of energy-transmission optic fibre is Δ λR, then λ2
=λ1+ΔλRWithin the scope of tunable ultra-low noise optical fiber laser output wavelength.
Wavelength division multiplexer implementation described in the utility model is unlimited, can be the diaphragm film coated type wave of fiber coupling
Division multiplexer, fused biconical taper formula wavelength division multiplexer, prismatic colours dissipate relationship type wavelength division multiplexer etc..Wavelength division multiplexer effect is will be to
The central wavelength for surveying the output of high power optical fibre laser system is λ1Laser and tunable wave length ultra-low noise optical fiber laser it is defeated
Central wavelength out is λ2Laser synthesizing be beam of laser output.
Energy-transmission optic fibre host material described in the utility model constitute it is unlimited, can be quartz, phosphate, silicate,
Sulfide etc.；Energy-transmission optic fibre core size, length are unlimited, with specific reference to high power optical fibre laser system to be measured output power and
The size of tunable wave length ultra-low noise optical fiber laser injecting power is determined according to formula (1)~formula (4).Energy-transmission optic fibre is fine
Core size and length combination meet effective non-linear Raman conversion.
Collimator described in the utility model realizes the collimation transmitting of output laser, can be by one or more lens
Combination is realized；The material of lens selects multiplicity, can be fused quartz, ZnSe, CaF2Deng.
Raman amplifiction rear center wavelength is λ by bandpass filter described in the utility model1Laser and remaining wave
A length of λ2Laser from two beams are spatially divided into, generally realized by multicoating filter sheet structure.
Power meter described in the utility model is λ for receiving Raman amplifiction rear center wavelength1Laser, and it is defeated to its
Power measures display out.
Useless light collector described in the utility model is λ for receiving remaining wavelength after Raman amplifiction2Laser,
It can be power meter, be also possible to useless light collector of taper etc..
Compared with prior art, the utility model can generate following technical effect:
1, the utility model provides a kind of steady based on pure optical detecting method evaluation high power optical fibre laser system time domain
Qualitative device.The laser of high power optical fibre laser system to be measured output serves as pumping laser, tunable super-low noise in the device
The laser of acousto-optic fibre laser output serves as signal light seed laser, and energy-transmission optic fibre provides Raman gain, put by preceding to Raman
Dependence between big signal optical output power and transfer efficiency and pump light time-domain stability, is put by simply measuring Raman
The output power of big signal light, and then Raman-amplifying signal light conversion efficiency is calculated, and with no time domain fluctuating ideal situation
Under Raman-amplifying signal optical output power and transfer efficiency compare, that is, can be evaluated high power optical fibre laser system to be measured when
Domain stability.Compared with Traditional photovoltaic detection method, the device avoids the deficiency of photodetection and processing module Bandwidth-Constrained,
With peculiar advantages such as responsive bandwidth height, fast response times, it can be used for evaluating the different times such as nanosecond and following, microsecond, millisecond
The time-domain stability characteristic of scale；
2, provided by the utility model a kind of steady based on pure optical detecting method evaluation high power optical fibre laser system time domain
Qualitative device has versatility: setting the central wavelength lambda of high power optical fibre laser system output laser to be measured1If energy-transmission optic fibre
Host material determines (i.e. raman gain medium determination, Raman Stokes shift amount Δ λRDetermine), it is tunable super by adjusting
The central wavelength lambda of Low-Noise Fiber Laser output laser2, it is made to meet λ2=λ1+ΔλR, which can realize
The evaluation of any wavelength high power optical fibre laser system time-domain stability；By rationally designing Injection Signal light seed power and mentioning
For fibre core covering ratio, length and the matrix type of the energy-transmission optic fibre of Raman gain, which can be used for any power
The evaluation of horizontal high power optical fibre laser system time-domain stability.
3, provided by the utility model a kind of steady based on pure optical detecting method evaluation high power optical fibre laser system time domain
In qualitative device, high power optical fibre laser system type to be measured is unlimited, output laser center wavelength is unlimited, can be output wave
Long covering ytterbium ion emission spectra wave band (1um wave band) mixes ytterbium high power optical fibre laser system, output wavelength covering erbium ion hair
Penetrate er-doped high power optical fibre laser system, the output wavelength covering thulium/holmium ion emission spectra wave band of spectrum wave band (1.55um wave band)
(2um wave band) mixes thulium/holmium high power optical fibre laser system, is also possible to output wavelength and covers other special Doped ions transmittings
Compose the high power optical fibre laser system of wave band；High power optical fibre laser system implementations to be measured are unlimited, can be direct Gao Gong
Rate oscillator, high power super-fluorescence light source, the random fiber laser system of high power are realized based on master oscillation power amplification structure
High power optical fibre laser system；High power optical fibre laser system line width to be measured is unlimited, can be single-frequency, narrow linewidth or general wide
Compose high power optical fibre laser system.
4, provided by the utility model a kind of steady based on pure optical detecting method evaluation high power optical fibre laser system time domain
In qualitative device, tunable wave length ultra-low noise optical fiber laser is generally single frequency optical fiber laser or single frequency optical fiber laser
Apply the narrow cable and wide optical fiber laser that phase-modulation generates.The implementation of single frequency optical fiber laser is unlimited, can be distribution
Feedback laser, Distributed Bragg Reflection laser, non-planar ring oscillator, single-frequency annular optical fiber laser, can also be with
It is the laser light source that single-frequency semiconductor laser passes through fiber coupling output；
5, provided by the utility model a kind of steady based on pure optical detecting method evaluation high power optical fibre laser system time domain
In qualitative device, wavelength division multiplexer implementation is unlimited, can be diaphragm film coated type wavelength division multiplexer, the melting of fiber coupling
Bevel-type wavelength division multiplexer, prismatic colours is drawn to dissipate relationship type wavelength division multiplexer etc.；Energy-transmission optic fibre host material composition is unlimited, can be stone
English, phosphate, silicate, sulfide etc.；The material of collimator lens selects multiplicity, can be fused quartz, ZnSe, CaF2Deng.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the utility model；
In figure: high power optical fibre laser system 1 to be measured, tunable wave length ultra-low noise optical fiber laser 2, wavelength division multiplexer
3, energy-transmission optic fibre 4, collimator 5, bandpass filter 6, power meter 7, useless light collector 8；
Fig. 2 is distribution map of the high power optical fibre laser system time domain light intensity to be measured in microsecond scale；
Fig. 3 is variation diagram of the 1120nm Raman amplifiction laser output power with pump power.
Specific embodiment
The embodiments of the present invention are described in detail below in conjunction with attached drawing, but the utility model can be by right
It is required that the multitude of different ways for limiting and covering is implemented.
Referring to Fig.1, for evaluating the device of high power optical fibre laser system time-domain stability, including high-power fiber to be measured
Laser system 1, tunable wave length ultra-low noise optical fiber laser 2, wavelength division multiplexer 3, energy-transmission optic fibre 4, collimator 5, band logical filter
Wave device 6, power meter 7, useless light collector 8.
Its output laser center wavelength of the high power optical fibre laser system 1 to be measured is λ1, the tunable wave length is ultralow
Its output laser center wavelength of noise fibre lasers 2 is λ2, its corresponding Raman Stokes shift amount of energy-transmission optic fibre 4 is Δ
λR, wherein tunable wave length ultra-low noise optical fiber laser 2 its export laser center wavelength λ2=λ1+ΔλR；
The laser that the high power optical fibre laser system 1 to be measured and tunable wave length ultra-low noise optical fiber laser 2 export
Beam of laser output is synthesized by wavelength division multiplexer 3, the laser beam after closing beam is injected into energy-transmission optic fibre 4.High power to be measured
The laser that fiber laser system 1 exports serves as pumping laser, and the laser that tunable ultra-low noise optical fiber laser 2 exports serves as letter
Number laser, energy-transmission optic fibre 4 provide Raman gain, in this way the Raman fiber laser amplifier structure of one forward pumping of composition.
The collimation output of laser beam collimator 5 exported through energy-transmission optic fibre 4, the laser beam exported from collimator 5 pass through band
It is λ that respectively central wavelength is divided into two bundles after bandpass filter 62Raman amplifiction laser and remaining central wavelength be λ1Laser,
Wherein central wavelength is λ2Raman amplifiction laser be injected into power meter 7, remaining central wavelength is λ1Laser be injected into useless light
Collector 8.
High-power fiber is evaluated based on the device shown in FIG. 1 for evaluating high power optical fibre laser system time-domain stability
The method of laser system time-domain stability, comprising the following steps:
(1) power and central wavelength lambda of high power optical fibre laser system output laser to be measured are measured1。
(2) determine the energy-transmission optic fibre used in device for evaluating high power optical fibre laser system time-domain stability and
Raman Stokes shift amount Δ λ corresponding to its host material of its energy-transmission optic fibreR。
(3) central wavelength lambda of tunable wave length ultra-low noise optical fiber laser output laser is determined2, λ2=λ1+ΔλR。
(4) output power of measurement tunable wave length ultra-low noise optical fiber laser output laser.
(5) it determines the core size and length of energy-transmission optic fibre, and calculates and rise and fall ideally Raman amplifiction without time domain
Laser power and Raman light conversion efficiency；
Raman amplifiction process in the Raman fiber laser amplifier structure of forward pumping comprising pumping laser time domain specification is logical
It is described before crossing to coupled amplitude equation, as described below:
Wherein: EpAnd EsRespectively represent the light field of pumping laser and signal laser, νgpAnd νgsRespectively represent pumping laser and
The group velocity of signal laser, β2pAnd β2sRespectively represent the group velocity dispersion coefficient of pumping laser and signal laser, αpAnd αsRespectively
Represent the loss factor of pumping laser and signal laser, δRFor variations in refractive index caused by Raman, fRIt is delay Raman response to non-
The decimal contribution (referred to as " contribution of decimal Raman ") linearly planned, gpAnd gsRespectively indicate the Raman of pumping laser and signal laser
Gain coefficient；γpAnd γsThe Kerr coefficient (nonlinear factor) for respectively representing pumping laser and signal laser, respectively indicates are as follows:
γp=2 π n2/λ1Aeff
γs=2 π n2/λ2Aeff (2)
Wherein, n2For nonlinear refractive index, AeffFor the effective core area of energy-transmission optic fibre；AeffWith energy-transmission optic fibre fibre core half
Dependence between diameter a indicates are as follows:
Aeff=Γ π a2 (3)
Wherein, Γ is relative scale coefficient, and value range is generally 0.8~1.
The light field E of pumping laser and signal laserpAnd EsMeet between pump laser power and signal laser power:
Wherein: dσFor along the effective core area A of energy-transmission optic fibreeffIntegral.
If Injection Signal laser (laser of i.e. tunable ultra-low noise optical fiber laser output) power is Ps(0), it injects
Pumping laser (i.e. the laser of high power optical fibre laser system to be measured output) power be PpIt (0), can using formula (1)-(4)
Be calculated high power optical fibre laser system to be measured without time domain rise and fall ideally Raman amplifiction laser power along energy-transmission optic fibre
The distribution P of longitudinal (i.e. energy-transmission optic fibre length direction)s(z).In conjunction with formula (1)~(4), the fiber core radius a of energy-transmission optic fibre is selected
And fiber lengths, enable to the pumping laser and tunable wave length super-low noise acousto-optic of high power optical fibre laser system output to be measured
The signal laser of fibre laser output being capable of effective Raman amplifiction and Raman conversion in energy-transmission optic fibre.
If the fiber lengths of energy-transmission optic fibre are L, then z=L, P are enabledsIt (L) is to pass through Raman amplifiction rear center wavelength for λ2's
The output power of laser；Therefore, Raman when high power optical fibre laser system to be measured ideally rises and falls without time domain converts effect
Rate ηs1It may be expressed as:
(6) it by the device for evaluating high power optical fibre laser system time-domain stability, is obtained using power meter measurement
Central wavelength is λ under actual conditions2Raman amplifiction laser output power Pse(L), and then actual Raman light is calculated
Efficiency etas2；ηs2Calculation formula it is as follows:
(7) actual measurement in step (6) is obtained central wavelength is λ2Raman amplifiction laser power Pse(L) and step
(5) what is be calculated in rises and falls ideally Raman amplifiction laser power power P without time domains(L) ratio operation is done, if the ratio
Value is R1；
Actual Raman light efficiency eta will be calculated in step (6)s2Be calculated in step (5) without time domain
The Raman light efficiency eta to rise and fall ideallys2Ratio operation is done, if ratio is R2。
Use R1Or use R2The time-domain stability of high power optical fibre laser system to be measured is directly evaluated, specific as follows:
Use R1Directly evaluate the time-domain stability of high power optical fibre laser system to be measured, ratio R1It is bigger, high power light to be measured
The time-domain stability of fiber laser system is poorer；Or use R2Directly evaluate the time-domain stability of high power optical fibre laser system to be measured
Property, ratio R2Bigger, the time-domain stability of high power optical fibre laser system to be measured is poorer.
The validity theory analysis that the utility model method is provided below is as follows:
If high power optical fibre laser system light intensity to be measured changes with time as follows:
I (t)=| f (t)+σ | (7)
Wherein: f (t) meets standardized normal distribution, and σ is the characteristic parameter of noise in time domain power.
Without loss of generality, if the central wavelength lambda of high power optical fibre laser system to be measured output laser1=1070nm, Raman
Gain media, that is, energy-transmission optic fibre selects fibre core covering than the silicon base medium optical fiber for 6/125 μm, 1070nm wave band its Raman this
Stokes shift amount Δ λRAbout 50 nm, then the central wavelength of tunable ultra-low noise optical fiber laser output laser is set as λ2
=1120nm.Ignore variations in refractive index δ caused by RamanR, other parameters typical value is as follows in formula (1): νgp=νgs=2 ×
108m/s、β2p=β2s=20ps2/km、αp=αs=0.015dB/m, fR=0.245, gp=4.4W-1/km、gs=4.2W-1/
Km, the influence for ignoring wavelength enable γp=γs=10 W-1/km。
If σ is respectively 0,1.5,2, high power optical fibre laser system time domain light intensity to be measured can be calculated micro- by formula (3)
The second distribution of scale is as shown in Figure 2.In Fig. 2, abscissa is the time (Time/us), ordinate is normalized intensity
(Normalized intensity/a.u.).It can be obtained by Fig. 2, with the increase of noise in time domain power characteristic parameter σ, height to be measured
Fiber optic power laser system time domain tends to be more stable.
Fig. 3 be according to utility model device, use time-domain stability different (as shown in Figure 1), central wavelength for
1070nm, maximum average output power~50W high power optical fibre laser system to be measured output laser as pump light, output work
Rate is 40mW, central wavelength is 1120 nm ultra-low noise optical fiber lasers as signal light seed, pumps 80 meters of fibre core covering ratios
For 6/125 μm of energy-transmission optic fibre, resulting 1120nm Raman amplifiction optical output power (Output is analyzed in conjunction with formula (1)~(4)
Power/W) with the variation of pump power (Pump power/W).It can be obtained by Fig. 3, pumping laser time domain is more stable, has when reaching
After imitating Raman switching threshold, the output power of Raman light is lower under identical pump power, i.e. Raman transfer efficiency is lower.On the contrary,
As pumping laser time-domain stability deteriorates, the output power of Raman light is higher under identical pump power, i.e. Raman transfer efficiency
It is higher.The physical interpretation of above-mentioned phenomenon is as follows: in the utility model device, the effective g-factor of Raman amplifiction can be with pump
Pu laser temporal it is instable increase and constantly become strong.Pumping laser time domain is more unstable, and corresponding high frequency section noise is got over
By force, effective Raman gain is higher, and then causes the output power of Raman amplifiction light higher, and Raman transfer efficiency is also higher.Into
And Raman amplifiction optical output power and transfer efficiency by being ideally calculated with the fluctuating of no time domain compare, i.e.,
Above-mentioned different time domain can be evaluated and rise and fall and be distributed the time-domain stability of high power optical fibre laser system to be measured.
It is steady for evaluating high power optical fibre laser system time domain that above-mentioned analysis result effectively demonstrates the utility model device
Qualitative feasibility.It should be understood that (i) although above-mentioned analytic process assumes λ1=1070nm, λ2=1120nm, once to
Survey the central wavelength lambda of high power optical fibre laser system output laser1It determines, raman gain medium determines (i.e. Raman Stokes
Frequency shift amount Δ λRDetermine), the central wavelength lambda of laser is exported by adjusting tunable ultra-low noise optical fiber laser2, make its satisfaction
λ2=λ1+ΔλR, which can realize the evaluation of any wavelength high power optical fibre laser system time-domain stability；
(ii) although above-mentioned analysis hypothesis high power optical fibre laser system maximum average output power~50W to be measured, foundation formula (1)~
(4), pass through fiber core radius, length and the base of rational design Injection Signal light seed power and the energy-transmission optic fibre that Raman gain is provided
Matter type, so that pump light can be realized effective Raman conversion, this method can be used for any power level high power optical fibre laser
The evaluation of system time-domain stability.
The foregoing is merely the preferred embodiments of the utility model, are not intended to limit the utility model, for
For those skilled in the art, various modifications and changes may be made to the present invention.All spirit and original in the utility model
Within then, any modification, equivalent replacement, improvement and so on be should be included within the scope of protection of this utility model.
Claims (10)
1. the device for evaluating high power optical fibre laser system time-domain stability, it is characterised in that: including high power light to be measured
Fiber laser system, tunable wave length ultra-low noise optical fiber laser, wavelength division multiplexer, energy-transmission optic fibre, collimator, bandpass filtering
Device, power meter, useless light collector；
Its output laser center wavelength of the high power optical fibre laser system to be measured is λ1, the tunable wave length super-low noise acousto-optic
Its output laser center wavelength of fibre laser is λ2, Raman Stokes shift amount corresponding to its host material of energy-transmission optic fibre is
ΔλR, wherein tunable wave length ultra-low noise optical fiber laser its export laser center wavelength λ2=λ1+ΔλR；
The high power optical fibre laser system to be measured and the laser of tunable wave length ultra-low noise optical fiber laser output pass through wave
Division multiplexer synthesizes beam of laser output, and the laser beam after closing beam is injected into energy-transmission optic fibre, through swashing for energy-transmission optic fibre output
The collimation output of light beam collimator, the laser beam exported from collimator are center wave by being divided into two bundles after bandpass filter respectively
A length of λ2Raman amplifiction laser and remaining central wavelength be λ1Laser, wherein central wavelength be λ2Raman amplifiction laser
It is injected into power meter, remaining central wavelength is λ1Laser be injected into useless light collector.
2. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: the laser of high power optical fibre laser system output to be measured serves as pumping laser, tunable ultra-low noise optical fiber laser output
Laser serve as signal laser, energy-transmission optic fibre provides Raman gain, and the Raman fiber laser of one forward pumping of composition in this way is put
Big structure.
3. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
It is that output wavelength covering ytterbium ion emission spectra wave band mixes ytterbium high power optical fibre laser system in: high power optical fibre laser system to be measured
System, the er-doped high power optical fibre laser system of output wavelength covering erbium ion emission spectra wave band or output wavelength cover thulium/holmium
Emission of ions spectrum wave band mixes thulium/holmium high power optical fibre laser system.
4. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
It is that direct high-power oscillator, high power super-fluorescence light source, the random optical fiber of high power swash in: high power optical fibre laser system to be measured
Photosystem or the high power optical fibre laser system realized based on master oscillation power amplification structure.
5. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: tunable wave length ultra-low noise optical fiber laser is single frequency optical fiber laser or applies phase-modulation to single frequency optical fiber laser
The narrow cable and wide optical fiber laser of generation, wherein single frequency optical fiber laser is distributed feedback laser, Distributed Bragg Reflection
Laser, non-planar ring oscillator, single-frequency annular optical fiber laser or single-frequency semiconductor laser pass through fiber coupling
The laser light source of output.
6. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: tunable wave length ultra-low noise optical fiber laser wavelength tuning range by the launch wavelength of high power optical fibre laser system to be measured
It determines；If the central wavelength of high power optical fibre laser system output laser to be measured is λ1, this support of its corresponding Raman of energy-transmission optic fibre
Gram this frequency shift amount is Δ λR, then λ2=λ1+ΔλRWithin the scope of tunable ultra-low noise optical fiber laser output wavelength.
7. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: wavelength division multiplexer is diaphragm film coated type wavelength division multiplexer, fused biconical taper formula wavelength division multiplexer or the prism dispersion of fiber coupling
Relationship type wavelength division multiplexer.
8. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: its host material of energy-transmission optic fibre is quartz, phosphate, silicate or sulfide.
9. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: collimator is formed by one or more lens combinations, and wherein the material of lens is fused quartz, ZnSe or CaF2。
10. according to claim 1 for evaluating the device of high power optical fibre laser system time-domain stability, feature exists
In: bandpass filter is realized by multicoating filter sheet structure.
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| CN108692918A (en) * | 2018-07-17 | 2018-10-23 | 中国人民解放军国防科技大学 | Device and method for evaluating time domain stability of high-power optical fiber laser system |
| CN110165530A (en) * | 2019-06-24 | 2019-08-23 | 中国人民解放军国防科技大学 | High-power Raman fiber laser generation method and system |
| CN110176712A (en) * | 2019-06-24 | 2019-08-27 | 中国人民解放军国防科技大学 | Random fiber laser generation method and system |
| CN113904206A (en) * | 2021-09-10 | 2022-01-07 | 中国科学院上海光学精密机械研究所 | Broadband optical signal amplification method based on supercontinuum |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108692918A (en) * | 2018-07-17 | 2018-10-23 | 中国人民解放军国防科技大学 | Device and method for evaluating time domain stability of high-power optical fiber laser system |
| CN108692918B (en) * | 2018-07-17 | 2023-12-15 | 中国人民解放军国防科技大学 | Device and method for evaluating time domain stability of high-power fiber laser system |
| CN110165530A (en) * | 2019-06-24 | 2019-08-23 | 中国人民解放军国防科技大学 | High-power Raman fiber laser generation method and system |
| CN110176712A (en) * | 2019-06-24 | 2019-08-27 | 中国人民解放军国防科技大学 | Random fiber laser generation method and system |
| CN110176712B (en) * | 2019-06-24 | 2023-11-17 | 中国人民解放军国防科技大学 | Random fiber laser generation method and system |
| CN110165530B (en) * | 2019-06-24 | 2024-01-26 | 中国人民解放军国防科技大学 | High-power Raman fiber laser generation method and system |
| CN113904206A (en) * | 2021-09-10 | 2022-01-07 | 中国科学院上海光学精密机械研究所 | Broadband optical signal amplification method based on supercontinuum |
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