CN112688147B - Pre-chirp management femtosecond laser pulse amplification device and system - Google Patents
Pre-chirp management femtosecond laser pulse amplification device and system Download PDFInfo
- Publication number
- CN112688147B CN112688147B CN202011559678.5A CN202011559678A CN112688147B CN 112688147 B CN112688147 B CN 112688147B CN 202011559678 A CN202011559678 A CN 202011559678A CN 112688147 B CN112688147 B CN 112688147B
- Authority
- CN
- China
- Prior art keywords
- femtosecond laser
- pulse
- chirp
- module
- management
- 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
Images
Landscapes
- Lasers (AREA)
Abstract
The invention provides a compact pre-chirp management femtosecond laser pulse amplification device, which comprises a femtosecond laser oscillator module, a pre-chirp management module, a bi-pass optical fiber amplifier module and a pulse compression module, wherein the femtosecond laser oscillator module is used for generating a laser pulse; the femtosecond pulse sequence output by the femtosecond laser oscillator module firstly passes through the pre-chirp management module to adjust the pulse chirp quantity, then passes through the double-pass optical fiber amplifier module to amplify power in a twice-pass mode and simultaneously broaden a spectrum, and then the pulse compression module compensates dispersion to compress and obtain sub-hundred femtosecond pulses. The method combines the pre-chirp amplification technology with the bi-pass amplification technology with high gain characteristic, so that the oscillator can obtain hundred watt sub-hundred femtosecond ultrashort pulses by adding a primary amplification structure, and the complexity of the pre-chirp amplification device is greatly reduced.
Description
Technical Field
The invention relates to the technical field of ultrafast lasers, in particular to an ultrafast fiber laser technology, and particularly relates to an ultrashort femtosecond pulse generating device.
Background
Because of the characteristics of high electro-optic conversion efficiency, outstanding heat dissipation performance and excellent beam quality, the ytterbium-doped ultrafast fiber laser is widely applied to the fields of industrial precision processing, biomedicine, national defense aerospace, scientific research and the like.
Ultrafast fiber laser systems typically employ Chirped Pulse Amplification (CPA) techniques in order to achieve pulses with high peak power while reducing nonlinear accumulation. The pulse width of the fiber CPA system output is typically greater than 200fs due to limitations imposed by the gain medium bandwidth and gain narrowing during amplification. The nonlinear amplification technology is provided to successfully break through the restriction of gain narrowing on pulse width, and the system can easily output micro-focus ultra-short pulses smaller than 100fs by reasonably controlling nonlinearity. The combination of the pre-chirp managed amplification (PCMA) technology in the nonlinear amplification technology and the large mode field fiber technology becomes a powerful means for obtaining hundred-watt sub-hundred femtosecond ultrashort pulses. However, the current hectowatt PCMA system is generally based on a structure of CPA front end plus rod-shaped optical fiber power amplification with a repetition frequency of tens of megahertz and a focus of tens of nanometers. Although the CPA front end can be made into a full-fiber structure, the CPA front end still includes a stretcher, a multi-level single-mode or even multi-mode fiber pre-amplification level, and a pump light source, a wavelength division multiplexer, an isolator, a beam combiner and the like which are matched with the CPA front end, and the complexity of the system is greatly increased due to the complex fiber structure. On the other hand, replacing the CPA front end with a Mamyshev oscillator that can directly output higher average power and pulse energy becomes a feasible method for reducing the complexity of the PCMA system, but the Mamyshev oscillator is difficult to self-start and is complex in structure, so that the Mamyshev oscillator is not a good solution.
The prior art PCMA technology has the following disadvantages:
1. the CPA front end or the Mamyshev oscillator as the front end both comprise a plurality of optical devices, which increases the complexity of the whole system.
2. The use of a multi-stage pre-amplification structure deteriorates the stability of the entire system.
Disclosure of Invention
Therefore, the present invention aims to overcome the defects in the prior art, and provides an ultrashort pulse laser amplification device with a simplified structure and based on the pre-chirp management technology, wherein the ultrashort pulse laser amplification device combines the high gain characteristic of a double-pass amplification structure and the power amplification level of a rod-shaped optical fiber, and replaces the existing CPA front end with a mode-locked optical fiber oscillator with a simple structure, so that the ultrashort pulse laser amplification device can directly amplify small-signal laser with dozens of milliwatts to the hundred watt level, and the method greatly reduces the complexity of the whole system structure.
To achieve the above object, a first aspect of the present invention provides a pre-chirp management femtosecond laser pulse amplification apparatus, including: the system comprises a femtosecond laser oscillator module, a pre-chirp management module, a bi-pass optical fiber amplifier module and a pulse compression module; wherein:
the output end of the femtosecond laser oscillator module is connected with the input end of the pre-chirp management module, and the femtosecond laser oscillator module is used for transmitting an ultrashort pulse sequence;
the output end of the pre-chirp management module is connected with the input end of the double-pass optical fiber amplifier module, and the pre-chirp management module is used for adjusting the chirp quantity of input pulses;
the output end of the double-pass optical fiber amplifier module is connected with the input end of the pulse compression module, and the double-pass optical fiber amplifier module is used for carrying out twice pass-type power amplification on the pulse output by the pre-chirp management module and widening a spectrum corresponding to the pulse by utilizing a nonlinear effect;
and the pulse compression module is used for carrying out dispersion compensation on the pulse output from the output end of the double-pass optical fiber amplifier module.
The pre-chirp management femtosecond laser pulse amplification device according to the first aspect of the invention, wherein the femtosecond laser oscillator module comprises a mode-locked fiber laser oscillator; and/or the central wavelength range of the ultrashort pulse sequence emitted by the femtosecond laser oscillator module is 1-1.06 μm, and the most preferable range is 1.03 μm;
preferably, the mode locking mode of the mode locking fiber laser oscillator is selected from one or more of the following modes: a semiconductor saturable absorber mirror, a nonlinear polarization rotating, nonlinear optical ring mirror;
more preferably, the mode-locked fiber laser oscillator is an ytterbium-doped fiber oscillator based on nonlinear polarization rotation mode locking.
The pre-chirp management femtosecond laser pulse amplification device comprises a pre-chirp management module, a pre-chirp management module and a pre-chirp management module, wherein the pre-chirp management module comprises a dispersion regulation and control device;
preferably, the dispersion tuning device is a grating pair and/or a prism pair, more preferably a grating pair.
The pre-chirp management femtosecond laser pulse amplification device comprises a pre-chirp management module, a first plane reflector, an angular reflector and an optical isolator, wherein the pre-chirp management module further comprises the first plane reflector, the angular reflector and the optical isolator;
the ultrashort pulse sequence emitted by the femtosecond laser oscillator module is emitted to the dispersion regulation device without blocking, is returned by the angular reflector and reduced by a certain height, then penetrates through the dispersion regulation device again, is reflected on the first plane reflector, and then penetrates through the optical isolator to output the pre-chirped pulse.
The pre-chirped management femtosecond laser pulse amplification device comprises a second plane reflector, a first polarization beam splitter, a first Faraday optical rotator, a first half wave plate, a second polarization beam splitter, a first plano-convex lens, a rod-shaped photonic crystal gain fiber, a second plano-convex lens, a third plane reflector, a first dichroic mirror, a second dichroic mirror, a third plano-convex lens, a diode-pumped laser source, a second Faraday optical rotator and a fourth plane reflector which are sequentially arranged;
preferably, the double-pass optical fiber amplifier module further includes a second half-wave plate and a pulse separating/combining device disposed between the second polarization beam splitter and the first plano-convex lens.
The pre-chirp management femtosecond laser pulse amplification device comprises a rod-shaped photonic crystal gain fiber, wherein the diameter of a fiber core of the rod-shaped photonic crystal gain fiber is 40-100 mu m, and is preferably 85 mu m; and/or
The length of the rod-shaped photonic crystal gain fiber is 60-120 cm, and preferably 80 cm.
The pre-chirp management femtosecond laser pulse amplification device according to the first aspect of the invention is characterized in that the clear aperture of the first Faraday rotator and the clear aperture of the second Faraday rotator are the same;
preferably, the clear aperture of the first Faraday rotator and the second Faraday rotator is 2-5mm, preferably 3 mm.
The pre-chirp managed femtosecond laser pulse amplification apparatus according to the first aspect of the present invention, wherein the pulse separation/synthesis device is selected from any one of: a polarization beam splitter prism is added with a delay line and a birefringent crystal;
preferably, the pulse separation/synthesis device is a birefringent crystal, and pulses are separated and synthesized in time by using group velocity difference of the birefringent crystal to the pulses with different polarization directions;
more preferably, the birefringent crystal is selected from one or more of: calcite, yttrium vanadate, barium borate, preferably yttrium vanadate;
further preferably, the thickness of the birefringent crystal ranges from 4mm to 10 mm.
The pre-chirp management femtosecond laser pulse amplification device according to the first aspect of the invention, wherein the pulse compression module comprises a dispersion compensation device;
preferably, the dispersion compensation device is selected from a grating pair, a prism pair or a chirped mirror;
more preferably, the pulse compression module includes a fifth plane mirror, a first chirped mirror, and a second chirped mirror.
A second aspect of the present invention provides a pre-chirp management laser pulse amplification system including the pre-chirp management femtosecond laser pulse amplification apparatus as described in the first aspect.
The invention provides a compact pre-chirp management femtosecond laser pulse amplification device, which comprises: the system comprises a femtosecond laser oscillator module, a pre-chirp management module, a bi-pass optical fiber amplifier module and a pulse compression module;
wherein:
the output end of the femtosecond laser oscillator module is connected with the input end of the pre-chirp management module, and the femtosecond laser oscillator module is used for transmitting a beam of ultrashort pulse sequence;
the output end of the pre-chirp management module is connected with the input end of the bi-pass optical fiber amplifier module, and the pre-chirp management module consists of a dispersion regulation and control device and is used for regulating the pre-chirp quantity of input pulses to optimize the final pulse compression effect;
the output end of the double-pass optical fiber amplifier module is connected with the input end of the pulse compression module; the double-pass optical fiber amplifier module is used for carrying out twice pass type power amplification on the pulse output by the pre-chirp management module and broadening a spectrum corresponding to the pulse by utilizing a nonlinear effect;
the pulse compression module is used for carrying out dispersion compensation on the pulse output from the output end of the double-pass optical fiber amplifier module so as to compress the pulse width and generate the ultrashort femtosecond pulse with high peak power.
According to the apparatus of the first aspect of the present invention, the femtosecond laser oscillator module is a mode-locked fiber laser oscillator, the mode-locking mode may be a semiconductor saturable absorber mirror, may be a nonlinear polarization rotation, may be a nonlinear optical ring mirror, and the like, and is preferably an ytterbium-doped fiber oscillator based on nonlinear polarization rotation mode-locking;
more preferably, the femtosecond laser oscillator emits ultrashort pulse sequences with a central wavelength ranging from 1 μm to 1.06 μm, and most preferably 1.03 μm.
The dispersion regulating and controlling device in the pre-chirp management module is a grating pair, a prism pair or a combination of the grating pair and the prism pair; preferably a grating pair.
The pre-chirp management module consists of a reflector and a grating pair;
preferably, the pre-chirp management unit includes a first plane mirror, a first transmission grating, a second transmission grating, an angular reflector, and an optical isolator.
The double-pass optical fiber amplifier module comprises a second plane reflector, a first polarization beam splitter, a first Faraday optical rotator, a first half-wave plate, a second polarization beam splitter, a first plano-convex lens, a rod-shaped photonic crystal gain optical fiber, a second plano-convex lens, a third plane reflector, a first dichroic mirror, a second dichroic mirror, a third plano-convex lens, a diode pump laser source, a second Faraday optical rotator and a fourth plane reflector which are sequentially arranged;
preferably, the double-pass fiber amplifier module further comprises a second half-wave plate and a pulse separating/combining device disposed between the second polarization beam splitter and the first plano-convex lens.
Further preferably, the pulse separation device and the pulse synthesis device are composed of birefringent crystals, and pulses are separated and synthesized in time by using group velocity differences of the birefringent crystals to the pulses with different polarization directions; the pulse separation device and the pulse synthesis device adopt a cascade mode inside, and can be flexibly expanded to increase the number of pulse decomposition and synthesis; the birefringent crystal is selected from one or more of: quartz crystals, calcite, yttrium vanadate or barium borate;
the dispersion compensation device in the pulse compression module is a grating pair, a prism pair or a chirped mirror;
preferably, the dispersion compensating device includes a fifth plane mirror, a first chirped mirror, and a second chirped mirror.
Based on the device, the invention provides a technical scheme that:
a compact pre-chirp managed femtosecond laser pulse amplification apparatus comprising: the system comprises a femtosecond laser oscillator module, a pre-chirp management module, a bi-pass optical fiber amplifier module and a pulse compression module; the output end of the femtosecond laser oscillator module is connected with the input end of a pre-chirp management module, and the output end of the pre-chirp management module is connected with the input end of a double-pass optical fiber amplifier module; the output end of the double-pass optical fiber amplifier module is connected with the input end of the pulse compression module;
the femtosecond laser oscillator module is used for emitting a beam of ultrashort pulse sequence A; the pre-chirp management module consists of a dispersion regulation and control device and is used for regulating the chirp quantity of an input pulse and outputting a pre-chirp pulse B; the double-pass optical fiber amplifier module is used for carrying out twice pass type power amplification on the pulse output by the pre-chirp management module, widening a spectrum corresponding to the pulse by utilizing a nonlinear effect and outputting a twice amplified pulse D; the pulse compression module is used for carrying out dispersion compensation on the pulse output from the output end of the double-pass optical fiber amplifier module so as to compress the pulse width and generate the ultrashort femtosecond pulse E with high peak power.
Further, the femtosecond laser oscillator module is a mode-locked fiber laser oscillator, the mode-locking mode can be a semiconductor saturable absorption mirror, can be nonlinear polarization rotation, can also be a nonlinear optical ring mirror, and the like, and is preferably a nonlinear polarization rotation mode-locked ytterbium-doped fiber oscillator with the central wavelength working at 1.03 μm;
furthermore, the pre-chirp management module consists of a reflector and a grating pair, and comprises a first plane reflector, a first transmission grating, a second transmission grating and an angular reflector; the first transmission grating and the second transmission grating are arranged in parallel, and the second transmission grating is arranged on the precise adjustable displacement platform and used for outputting the pre-chirped pulse B from the optical isolator after adjusting the distance between the grating pairs to change the chirp quantity of the incident pulse.
Furthermore, the double-pass optical fiber amplifier module works in a double-pass mode and can provide enough gain for a low-power laser signal to realize high-power amplification; the device specifically comprises a second plane reflector, a first polarization beam splitter prism, a first Faraday optical rotator, a first half-wave plate, a second polarization beam splitter prism, a first plano-convex lens, a rod-shaped photonic crystal gain optical fiber, a second plano-convex lens, a first dichroic mirror, a second Faraday optical rotator, a fourth plane reflector, a second dichroic mirror, a third plano-convex lens and a diode pump laser source which are sequentially arranged; the pre-chirped pulse B can be efficiently coupled into a fiber core of the rod-shaped photonic crystal gain fiber by adjusting the second plane mirror and the first plano-convex lens; the third plano-convex lens, the second dichroic mirror, the first dichroic mirror and the second plano-convex lens are used for coupling the pump light output by the diode pump laser source into a cladding of the gain fiber to provide gain for the pre-chirped pulse B; the second dichroic mirror is also used for spatially separating the amplified pulse C output by the gain fiber from the pump laser, and the separated signal pulse can pass through the second Faraday optical rotator twice and rotate the polarization direction of the pulse by 90 degrees by reflecting through the fourth plane mirror so as to generate a primary amplified pulse sequence C; the second polarization beam splitter prism is used for spatially separating the secondary amplification pulse D amplified by the rod-shaped photonic crystal gain fiber again from the incident beam, and a small number of beams which are not successfully separated leak from the reflection end of the first polarization beam splitter prism after passing through the first half-wave plate and the first Faraday optical rotator.
Furthermore, the double-pass optical fiber amplifier module also comprises a second half-wave plate and a pulse separation/synthesis device which are arranged between the second polarization beam splitter prism and the first plano-convex lens; the pre-chirped pulse B can be separated into time-independent sub-pulses with equal strength and orthogonal polarization after the pulse separating device is adjusted by the second half-wave plate, and the pulse polarization direction can be rotated by 90 degrees by the second Faraday optical rotator due to the adoption of a double-pass structure, so that the delay between pulses can be compensated by reversely passing through the pulse separating device for the second time to realize a synthesis function, namely the pulse separating device and the pulse synthesizing device are the same device.
Further, the pulse compression module consists of a fifth plane mirror, a first chirped mirror and a second chirped mirror; the first chirped mirror and the second chirped mirror are used for compensating the dispersion compression amplification pulse C to generate an ultrashort femtosecond pulse D.
Compared with the prior art, the compact pre-chirp management femtosecond laser pulse amplification device has the following beneficial effects that:
1. the structure is simple, the advantages of the pre-chirp management amplification technology and the double-pass optical fiber amplification technology are ingeniously combined, and the micro-focus ultrashort femtosecond pulse of hundred watt horizontal sub-50 fs can be obtained only by utilizing one optical fiber oscillator and one rod-shaped optical fiber amplifier.
2. The device is compatible with pulse division amplification technology, a pulse separation/synthesis unit can be added on the basis of the existing system to improve the output pulse energy of the system, and the adoption of a bi-pass structure ensures that a set of pulse division devices simultaneously takes the pulse synthesis function into consideration, thereby being beneficial to simplifying the device.
Drawings
Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:
fig. 1 shows a compact pre-chirp managed femtosecond laser pulse amplification apparatus based on a birefringent crystal.
Fig. 2 shows a schematic diagram of the process of pulse decomposition realized by the yttrium vanadate birefringent crystal.
Fig. 3 shows a pulse separating/combining device in embodiment 2, which is served by a polarization beam splitting device.
Fig. 4 shows an autocorrelation curve of a pulse after the oscillator output signal light passes through the pre-chirp unit in experimental example 1.
Fig. 5 shows a spectrum corresponding to the oscillator output signal light in experimental example 1.
FIG. 6 shows the pulse autocorrelation curves corresponding to the double pass amplification of the rod-shaped optical fiber to 72W in Experimental example 1.
FIG. 7 shows the output spectrum of the rod-shaped optical fiber of test example 1 when it was double-pass amplified to 72W.
Description of reference numerals:
1. a femtosecond laser oscillator module; 2. a pre-chirp management module; 3. a double-pass fiber amplifier module; 4. a pulse compression module; 5. a first planar mirror; 6. a first transmission grating; 7. a second transmission grating; 8. an angular reflector; 9. an optical isolator; 10. a second planar mirror; 11. a first polarization beam splitter prism; 12. a first Faraday rotator; 13. a first half wave plate; 14. a second polarization beam splitter prism; 15. a second half-wave plate; 16. a pulse separating/combining device; 17. a first plano-convex lens; 18. a rod-shaped photonic crystal gain fiber; 19. a second plano-convex lens; 20. a third plane mirror; 21. a first dichroic mirror; 22. a second Faraday rotator; 23. a fourth plane mirror; 24. a second dichroic mirror; 25. a third plano-convex lens; 26. a diode pump laser source, 27, a fifth plane mirror; 28. a first chirped mirror; 29. a second chirped mirror; 30. a polarization beam splitter prism; 31. a quarter wave plate; 32. a plane mirror; 33. a quarter wave plate; 34. a plane mirror; 1601. a birefringent crystal.
A. An ultrashort pulse train emitted from the femtosecond laser oscillator 1; B. the pre-chirp management module 2 outputs pre-chirp pulses; C. pulses with the polarization direction rotated by 90 degrees are obtained after the second rotating mirror is pulled twice; D. a secondary amplification pulse sequence output by the double-pass optical fiber amplifier module 3; E. the pulse compression module 4 compresses the output ultrashort femtosecond pulses.
Detailed Description
The invention is further illustrated by the following specific examples, which, however, are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.
This section generally describes the materials used in the testing of the present invention, as well as the testing methods. Although many materials and methods of operation are known in the art for the purpose of carrying out the invention, the invention is nevertheless described herein in as detail as possible. It will be apparent to those skilled in the art that the materials and methods of operation used in the present invention are well within the skill of the art, provided that they are not specifically illustrated.
In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1
This embodiment is used to illustrate the structure of a compact pre-chirp managed femtosecond laser pulse amplification apparatus according to the present invention. Fig. 1 is a compact pre-chirp management femtosecond laser pulse amplification device based on a birefringent crystal. It includes: the device comprises a femtosecond laser oscillator module 1, a pre-chirp management module 2, a double-pass optical fiber amplifier module 3 and a pulse compression module 4.
The femtosecond laser oscillator module 1 adopts a nonlinear polarization rotation mode-locked ytterbium-doped fiber oscillator of spatial light output, and the corresponding parameters of the output ultrashort pulse sequence A are as follows: the center wavelength is 1.03 mu m, the full width at half maximum of the spectrum is 15nm, the repetition frequency is 50MHz, and the diameter of a light spot is 1 mm. The ultra-short pulse sequence A directly enters a grating pair consisting of a first transmission grating 6 and a second transmission grating 7, the first transmission grating 6 and the second transmission grating 7 are placed in parallel, the second transmission grating 7 is installed on a precise adjustable displacement platform, the distance between the grating pairs can be flexibly controlled, the pulse sequence is turned back downwards through an angular reflector 8, is reduced by a certain height, returns again and penetrates through the grating pair, and finally is reflected by a first plane reflector 5 at an angle of 45 degrees and then penetrates through an optical isolator 9, and a pre-chirped pulse B is output;
the pre-chirped pulse B is reflected by a second plane mirror 10, then is completely transmitted through a first polarization beam splitter prism 11 in horizontal polarization, is rotated by 45 degrees by a first Faraday rotator 12, is then rotated to the horizontal direction by a first half-wave plate 13, is transmitted through a second polarization beam splitter prism 14, and is then coupled into a fiber core of a rod-shaped photonic crystal gain fiber 18 by a first plano-convex lens 17. The pump light output by the diode pump laser source 26 is coupled into the cladding of the rod-shaped photonic crystal gain fiber 18 through the third plano-convex lens 25, the second dichroic mirror 24, the first dichroic mirror 21 and the second plano-convex lens 19 to provide gain. The first dichroic mirror 21 is used to spatially separate the amplified pulse from the pump light, the amplified pulse passes through the second faraday optical rotator 22 and then is reflected by the fourth plane mirror 23 to return along the original path, and the polarization direction of the pulse C generated after passing through the second faraday optical rotator 22 for the second time is rotated by 90 degrees. The pulse C with the polarization direction rotated by 90 degrees passes through the rod-shaped photonic crystal gain fiber 18 for the second time to obtain higher gain, and then is reflected by the second polarization beam splitter prism 14 to be output to generate a secondary amplification pulse sequence D, and a small amount of light beam with non-vertical polarization leaks from the reflection end of the first polarization beam splitter prism 11. The diameter of the fiber core of the rod-shaped photonic crystal gain fiber 18 is 85 micrometers, and the length of the fiber core is 80 cm; the light-transmitting apertures of the first Faraday rotator 12 and the second Faraday rotator 22 are both 3mm, and the light-transmitting surfaces are coated with antireflection films at 750nm-1100nm, so that the polarization direction of light beams passing through each time can be rotated by 45 degrees.
The double-pass optical fiber amplifying module further includes a second half-wave plate 15 and a pulse separating/combining device 16 disposed between the second polarization beam splitting prism 14 and the first plano-convex lens 17. The adjustment of the second half-wave plate 15 to the pulse polarization state can obtain a pair of orthogonal polarization pulses with separated time after the pulse separating/synthesizing device 16, the pulse polarization direction amplified by the rod-shaped photonic crystal fiber in a double-pass mode can also rotate by 90 degrees, and then the pulse polarization direction can be compensated by reversely passing through the pulse separating device, so that the effect of pulse synthesis can be achieved.
In a preferred embodiment, the pulse separation/synthesis device 16 is selected as a yttrium vanadate birefringent crystal 1601, the length, width, and thickness dimensions of the yttrium vanadate birefringent crystal 1601 being 10mm × 10mm × 10mm, the crystal thickness being selected based on the refractive index difference between the selected birefringent crystal o and e light and the required pulse separation time, for example: as known from the knowledge of crystal optics, o light and e light in the yttrium vanadate birefringent crystal generate 750fs/mm time delay for pulses in the orthogonal polarization direction, and if the pulse width of the pulses after double-pass amplification is 3ps, the required thickness of the yttrium vanadate birefringent crystal needs at least 4mm to completely separate or synthesize the 3ps pulses. The specific pulse decomposition process is shown in fig. 2, and the pulse decomposition process can be understood as follows: after linear polarization pulses with an included angle of 45 degrees with the horizontal plane pass through the birefringent crystal, because the direct incident rates of the birefringent crystal to o light and e light are different, namely, the pulses with different polarizations will generate time walk away, one linear polarization pulse can be decomposed into a pair of orthogonal polarization pulses with time intervals in time by utilizing the principle.
The second amplified pulse sequence D output by the double-pass fiber amplification module is reflected by the fifth plane mirror 27, and then reflected for multiple times between the first chirped mirror 28 and the second chirped mirror 29 to achieve the dispersion compensation effect, and the reflection times are determined according to the dispersion amount to be compensated. After dispersion compensation, a micro-focus ultra-short femtosecond pulse E with the compression of more than 100W and less than 100fs can be obtained.
In the embodiment, the characteristics of directly generating sub-hundred femtosecond pulses by the pre-chirped amplification technology and the advantages of bi-pass fiber amplification are combined, and the ultra-short pulse output with the hundred watt horizontal micro-focus level less than 100fs can be realized by using the structure of the fiber oscillator and the bi-pass amplification of the first-level rod-shaped fiber. The invention is beneficial to simplifying the device complexity of the output parameter fiber laser system, and is compatible with the pulse division amplification technology, so that the single pulse energy output by the system is further improved.
Example 2
This embodiment is used to illustrate a compact pre-chirp managed femtosecond laser pulse amplification apparatus according to the present invention. This embodiment is different from embodiment 1 only in that the pulse splitting/combining device 16 of the double-pass fiber amplifying module is replaced with the structure shown in fig. 3, that is, the pulse splitting and combining process can be performed by using the structure shown in fig. 3.
Taking the pulse splitting function as an example, a linearly polarized pulse is incident into the structure of fig. 3 along the direction of the dotted arrow with a polarization direction of 45 degrees from the horizontal plane, and after passing through the polarization beam splitter prism 30, is split into a horizontally polarized pulse and another vertically polarized pulse. The horizontal polarization pulse directly penetrates through the polarization beam splitter prism 30, and the vertical polarization pulse is reflected in the polarization beam splitter prism 30, passes through the 1/4 wave plate 31, is reflected by the reflector 32, and then passes through the 1/4 wave plate 31 again. After passing through 1/4 wave plate 31 twice, the vertically polarized pulse becomes a horizontally polarized pulse and is directly transmitted through the polarization beam splitter prism 30. According to the same process, the horizontally polarized pulse firstly passes through 1/4 wave plate 33, then is reflected by mirror 34 and then passes through 1/4 wave plate 33 twice, the polarization angle is converted to 90 degrees and becomes vertically polarized pulse, and then the vertically polarized pulse is reflected in polarization beam splitting prism 30 and then is coincided with the incident light beam. Through the structure, a linear polarization pulse can generate two front and rear pulses with different polarization states which are transmitted in the same direction, and the pulse decomposition function is realized. The pulse synthesis function can be realized by reversely using the structure.
Test example 1
This test example is intended to illustrate the effects of the device of the present invention.
According to the detailed contents of the present embodiment and the experimental apparatus of fig. 1, the inventor performed preliminary experimental verification, and the experimental apparatus also includes: the device comprises a femtosecond laser oscillator module 1, a pre-chirp management module 2, a double-pass optical fiber amplifier module 3 and a pulse compression module 4. The difference from the experimental setup of fig. 1 is that the double-pass fiber amplifier module has no second half-wave plate 15 and no pulse separation/synthesis device 16 in the preliminary verification experiment, but this does not affect the feasibility of verifying the method of the present invention.
A double-pass pre-chirped management rod-shaped optical fiber amplification experiment is carried out by using 15mW ultrashort pulse laser output by a semiconductor saturable absorber mode-locked optical fiber oscillator as signal light.
The oscillator output parameters used for the experiments were: average power 15mW, repetition frequency 44MHz, full width at half maximum of spectrum 4.5nm, corresponding to conversion limit pulse width 200 fs. The power of the signal light coupled into the rod-shaped optical fiber after passing through the grating pair pre-chirping unit is about 10mW, and the experimental results after double-pass amplification are shown in fig. 4 to 7:
fig. 4 is a pulse autocorrelation curve obtained by measuring signal light output by an oscillator after passing through a pre-chirp unit, where the pulse width is 800fs after pre-chirp. FIG. 5 is a plot of the spectrum corresponding to the pulse of FIG. 4, shown in logarithmic scale, with a full width at half maximum of 4.5 nm. The 15mW pre-chirped pulse shown in FIG. 4 is used as signal light, and is coupled into the rod-shaped photonic crystal gain fiber 18 for power amplification, and after double-pass amplification, an output with an average power of 72W is obtained, and the gain is as high as 37 dB. FIG. 6 is a graph of the pulse autocorrelation corresponding to the rod-shaped photonic crystal fiber when the fiber is amplified to 72W in a double pass mode, wherein the graph shows that the pulse width 43fs is significantly reduced compared with that of FIG. 4. FIG. 7 shows the spectrum corresponding to 72W output after double pass amplification of the rod-shaped photonic crystal fiber, and compared with FIG. 5, the spectral width is significantly widened.
In conclusion, the inventor performs a rod-shaped photonic crystal fiber double-pass amplification experiment by using 15mW signal light directly output by a fiber oscillator, wherein about 10mW signal light is directly amplified to 72W, the gain is as high as 37dB, and the pulse width is 43fs after compression. In view of this, we demonstrate the novelty and advancement of a compact pre-chirp managed femtosecond laser pulse amplification device in generating fifty-second femtosecond ultrashort pulses at the hundred watt level of micro-focus.
Although the present invention has been described to a certain extent, it is apparent that appropriate changes in the respective conditions may be made without departing from the spirit and scope of the present invention. It is to be understood that the invention is not limited to the described embodiments, but is to be accorded the scope consistent with the claims, including equivalents of each element described.
Claims (22)
1. A pre-chirp managed femtosecond laser pulse amplification apparatus, characterized in that the apparatus comprises: the system comprises a femtosecond laser oscillator module, a pre-chirp management module, a bi-pass optical fiber amplifier module and a pulse compression module; wherein:
the output end of the femtosecond laser oscillator module is connected with the input end of the pre-chirp management module, and the femtosecond laser oscillator module is used for transmitting an ultrashort pulse sequence;
the output end of the pre-chirp management module is connected with the input end of the double-pass optical fiber amplifier module, and the pre-chirp management module is used for adjusting the chirp quantity of input pulses;
the output end of the double-pass optical fiber amplifier module is connected with the input end of the pulse compression module, and the double-pass optical fiber amplifier module is used for carrying out twice pass-type power amplification on the pulse output by the pre-chirp management module and widening a spectrum corresponding to the pulse by utilizing a nonlinear effect;
and the pulse compression module is used for carrying out dispersion compensation on the pulse output from the output end of the double-pass optical fiber amplifier module.
2. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 1, wherein the femtosecond laser oscillator module comprises a mode-locked fiber laser oscillator; and/or
The central wavelength range of the ultrashort pulse sequence emitted by the femtosecond laser oscillator module is 1-1.06 mu m.
3. The pre-chirped management femtosecond laser pulse amplification device according to claim 2, wherein the center wavelength range of the ultrashort pulse sequence emitted by the femtosecond laser oscillator module is 1.03 μm; and/or
The mode locking mode of the mode locking fiber laser oscillator is selected from one or more of the following modes: semiconductor saturable absorber mirror, nonlinear polarization rotating, nonlinear optical ring mirror.
4. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 3, wherein the mode-locked fiber laser oscillator is an ytterbium-doped fiber oscillator based on nonlinear polarization rotation mode locking.
5. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 1, wherein the pre-chirp management module comprises a dispersion regulation device.
6. The pre-chirp managed femtosecond laser pulse amplification apparatus according to claim 5, wherein the dispersion adjustment and control device is a grating pair and/or a prism pair.
7. The pre-chirp managed femtosecond laser pulse amplification apparatus according to claim 6, wherein the dispersion adjustment and control device is a grating pair.
8. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 5, wherein the pre-chirp management module further comprises a first plane mirror, an angle mirror, and an optical isolator;
the ultrashort pulse sequence emitted by the femtosecond laser oscillator module is emitted to the dispersion regulation device without blocking, is returned by the angular reflector and reduced by a certain height, then penetrates through the dispersion regulation device again, is reflected on the first plane reflector, and then penetrates through the optical isolator to output the pre-chirped pulse.
9. The apparatus of claim 1, wherein the dual pass fiber amplifier module comprises a second plane mirror, a first polarization beam splitter, a first faraday rotator, a first half wave plate, a second polarization beam splitter, a first plano-convex lens, a rod-shaped photonic crystal gain fiber, a second plano-convex lens, a third plane mirror, a first dichroic mirror, a second dichroic mirror, a third plano-convex lens, a diode-pumped laser source, a second faraday rotator, and a fourth plane mirror, which are sequentially arranged.
10. The pre-chirped management femtosecond laser pulse amplification apparatus according to claim 9, wherein the double-pass fiber amplifier module further comprises a second half-wave plate and a pulse separation/synthesis device disposed between the second polarization beam splitter and the first plano-convex lens.
11. The pre-chirped management femtosecond laser pulse amplification device according to claim 9, wherein the diameter of the fiber core of the rod-shaped photonic crystal gain fiber is 40-100 μm; and/or
The length of the rod-shaped photonic crystal gain fiber is 60-120 cm.
12. The pre-chirped management femtosecond laser pulse amplification device according to claim 11, wherein the core diameter of the rod-shaped photonic crystal gain fiber is 85 μm; and/or
The length of the rod-shaped photonic crystal gain fiber is 80 cm.
13. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 9, wherein the light transmission apertures of the first faraday rotator and the second faraday rotator are the same.
14. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 13, wherein the light transmission apertures of the first and second faraday rotators are 2-5 mm.
15. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 14, wherein the light transmission aperture of the first faraday rotator and the second faraday rotator is 3 mm.
16. The pre-chirp managed femtosecond laser pulse amplification apparatus according to claim 10, wherein the pulse separation/synthesis device is selected from any one of: the polarizing beam splitter prism is added with a delay line and a birefringent crystal.
17. The pre-chirped management femtosecond laser pulse amplification device according to claim 16, wherein the pulse separation/synthesis device is a birefringent crystal, and pulses are separated and synthesized in time by using group velocity difference of the birefringent crystal to pulses with different polarization directions.
18. The pre-chirp managed femtosecond laser pulse amplification apparatus according to claim 17, wherein the birefringent crystal is selected from one or more of: calcite, yttrium vanadate, barium borate; and/or
The thickness range of the birefringent crystal is 4-10 mm.
19. The pre-chirp management femtosecond laser pulse amplification apparatus according to claim 18, wherein the birefringent crystal is yttrium vanadate.
20. The pre-chirped management femtosecond laser pulse amplification apparatus according to claim 1, wherein the pulse compression module comprises a dispersion compensation device.
21. The pre-chirp managed femtosecond laser pulse amplification apparatus according to claim 20, wherein the dispersion compensation device is selected from a grating pair, a prism pair, or a chirped mirror; and/or
The pulse compression module includes a fifth plane mirror, a first chirped mirror, and a second chirped mirror.
22. A pre-chirp management laser pulse amplification system, comprising the pre-chirp management femtosecond laser pulse amplification apparatus according to any one of claims 1 to 21.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011559678.5A CN112688147B (en) | 2020-12-25 | 2020-12-25 | Pre-chirp management femtosecond laser pulse amplification device and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011559678.5A CN112688147B (en) | 2020-12-25 | 2020-12-25 | Pre-chirp management femtosecond laser pulse amplification device and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112688147A CN112688147A (en) | 2021-04-20 |
| CN112688147B true CN112688147B (en) | 2022-05-03 |
Family
ID=75453232
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011559678.5A Active CN112688147B (en) | 2020-12-25 | 2020-12-25 | Pre-chirp management femtosecond laser pulse amplification device and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112688147B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114512889B (en) * | 2022-02-15 | 2023-08-08 | 天津大学四川创新研究院 | Cluster type pulse generator and high-power narrow pulse width ultrashort pulse laser |
| CN114498275A (en) * | 2022-03-31 | 2022-05-13 | 武汉华锐超快光纤激光技术有限公司 | High-power femtosecond laser and power amplification method of high-power femtosecond laser |
| CN118318360A (en) * | 2022-07-22 | 2024-07-09 | 中国科学院物理研究所 | Femtosecond laser pulse energy lifting device based on composite birefringent crystal and application |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6151338A (en) * | 1997-02-19 | 2000-11-21 | Sdl, Inc. | High power laser optical amplifier system |
| US7256930B2 (en) * | 2003-04-15 | 2007-08-14 | Jian Liu | High power pulse shaping fiber laser for high data rate free space telecommunication systems |
| CN102270810A (en) * | 2011-05-10 | 2011-12-07 | 清华大学 | Method for reducing nonlinear effect in optical fiber amplifier and realizing environmental stabilization |
| CN111641098A (en) * | 2020-04-24 | 2020-09-08 | 科谱(宁波)科技有限公司 | Device for generating high-energy ultrashort pulse and working method thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3489974B2 (en) * | 1996-09-05 | 2004-01-26 | 科学技術振興事業団 | Ultrashort pulse light generation method and generator |
| CN105826807A (en) * | 2016-05-13 | 2016-08-03 | 中山大学 | Full waveband-adjustable highly integrated femtosecond pulse chirped pulse amplify-broaden/compress device |
| CN111934176A (en) * | 2020-08-07 | 2020-11-13 | 中国科学院物理研究所 | Few-cycle-magnitude high-energy femtosecond pulse generation device and application |
-
2020
- 2020-12-25 CN CN202011559678.5A patent/CN112688147B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6151338A (en) * | 1997-02-19 | 2000-11-21 | Sdl, Inc. | High power laser optical amplifier system |
| US7256930B2 (en) * | 2003-04-15 | 2007-08-14 | Jian Liu | High power pulse shaping fiber laser for high data rate free space telecommunication systems |
| CN102270810A (en) * | 2011-05-10 | 2011-12-07 | 清华大学 | Method for reducing nonlinear effect in optical fiber amplifier and realizing environmental stabilization |
| CN111641098A (en) * | 2020-04-24 | 2020-09-08 | 科谱(宁波)科技有限公司 | Device for generating high-energy ultrashort pulse and working method thereof |
Non-Patent Citations (2)
| Title |
|---|
| Divided-pulse nonlinear compression;Arno Klenke;《OPTICS LETTERS》;20131130;第38卷(第22期);正文第一节、附图1、4 * |
| Generation of megawatt peak power picosecond pulses from a divided-pulse fiber amplifier;L.J.Kong;《OPTICS LETTERS》;20120131;第37卷(第2期);正文第一节、附图1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112688147A (en) | 2021-04-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112688147B (en) | Pre-chirp management femtosecond laser pulse amplification device and system | |
| US8248688B2 (en) | Tandem photonic amplifier | |
| US7920606B2 (en) | Frequency-tripled fiber MOPA | |
| US7733922B1 (en) | Method and apparatus for fast pulse harmonic fiber laser | |
| CN106911060B (en) | The high-efficiency high power mid-infrared laser device of Wavelength tunable | |
| CN113410739A (en) | Pre-chirped management femtosecond pulse laser coherent synthesis amplifying device and system thereof | |
| US8373924B2 (en) | Frequency-tripled fiber MOPA | |
| CN110323663B (en) | Device and method for generating vector ultrashort laser pulse of intermediate infrared band | |
| CN112421353A (en) | Device for inhibiting gain narrowing and obtaining ultrashort pulse amplification output and adjusting method | |
| CN113067239B (en) | Intermediate infrared femtosecond pulse laser | |
| CN111641098A (en) | Device for generating high-energy ultrashort pulse and working method thereof | |
| CN113745951A (en) | Laser device | |
| CN211981130U (en) | Laser device | |
| CN113708203B (en) | Stable high-power ultrashort pulse generating system | |
| CN111180985B (en) | Experimental device and method for generating high repetition frequency femtosecond laser | |
| JP2021132070A (en) | Pulse laser light generation transmission device and laser processing device | |
| CN219123662U (en) | Picosecond ultraviolet laser | |
| US20240235145A9 (en) | Divided-pulse laser regeneration amplification apparatus and method | |
| CN220628475U (en) | Chirped pulse amplifying device based on spectrum modulation | |
| CN113675712B (en) | Deep ultraviolet ytterbium-doped fiber laser | |
| CN113725705B (en) | Green light pulse source based on spectrum shaping | |
| CN113659416B (en) | Dual-wavelength laser coaxial output system and method | |
| CN113078541B (en) | Orthogonal polarization dual-wavelength Q-switched laser based on Nd, MgO and LN and method | |
| CN113991399B (en) | Bidirectional isolation ring laser amplification device, method and system based on circular polarization | |
| CN117374702A (en) | Amplification device based on homodromous double-pass, amplification method thereof and fiber laser |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |