Due to their unique physical properties,nonlinear materials are gradually demonstrating significant potential in the field of optics.Gold nanoparticles supported on carbon black(Au/CB),possessing low loss and high non...Due to their unique physical properties,nonlinear materials are gradually demonstrating significant potential in the field of optics.Gold nanoparticles supported on carbon black(Au/CB),possessing low loss and high nonlinear characteristics,serve as an excellent material for saturable absorber(SA) in ultrafast fiber lasers.In this study,we investigated the performance of Au/CB material and designed an ultrafast fiber laser based on Au/CB SA,successfully observing stable fundamental mode-locking and pulse bunch phenomena.Specifically,when the fiber laser operates in fundamental mode-locking state,the center wavelength of optical spectrum is 1 558.82 nm,with a 3 dB bandwidth of 2.26 nm.Additionally,to investigate the evolution of real-time spectra,the dispersive Fourier transform(DFT) technology is employed.On the other hand,the pulse bunch emitted by the laser is actually composed of numerous random sub-pulses,exhibiting high-energy characteristics.The number of sub-pulses increases with the increase of pump power.These findings contribute to further exploring the properties of Au/CB material and reveal its potential applications in ultrafast optics.展开更多
This study systematically investigates the attractor characteristics of harmonic solitons in a passively modelocked fiber laser.Through comprehensive analysis in both time and frequency domains,we examine the evolutio...This study systematically investigates the attractor characteristics of harmonic solitons in a passively modelocked fiber laser.Through comprehensive analysis in both time and frequency domains,we examine the evolution of pulse width,spectral bandwidth,and energy across different harmonic orders.The results demonstrate typical soliton attractor behaviors,including attractiveness,dissipativity,and self-organization.In the transition regions between harmonic orders,breathing harmonic soliton states are captured using the time-stretched dispersive Fourier transform.By comparing the breathing dynamics with the stable states,the existence and self-organizing nature of soliton attractors are further confirmed.Finally,harmonic soliton attractors are employed as programmable light sources to achieve ternary optical coding.展开更多
Currently,the performance,cost,and environmental sustainability of saturable absorbers(SAs)represent major bottlenecks in the development of ultrafast fiber lasers.However,the development of high-performance SAs remai...Currently,the performance,cost,and environmental sustainability of saturable absorbers(SAs)represent major bottlenecks in the development of ultrafast fiber lasers.However,the development of high-performance SAs remains challenging due to intricate fabrication processes and inadequate nonlinear performance.In this context,this work presents the natural alkaloid berberine as a promising alternative for mode-locked erbium-doped fiber lasers.The berberine-based SA exhibits excellent nonlinear optical properties,including a modulation depth of 24.40%and a saturation intensity of 1.281MW/cm^(2),and successfully enables stable femtosecond pulse generation.By employing time-stretched dispersive Fourier transform technology,the transient dynamics results indicate that the berberine-based SA significantly shortens the relaxation oscillation time and effectively suppresses pulse intensity fluctuations,thereby accelerating the self-starting process of mode-locking.This work provides a new strategy for developing high-performance,low-cost,and environmentally friendly ultrafast photonic devices,significantly advancing the practical application of green SAs.展开更多
As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ene...As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ener-gy,biomedicine,optoelectronic devices,and so on.At present,there have been scant reports on the application of NiTe_(2)in the field of ultrafast photonics.In this work,NiTe_(2)was synthesized by chemical vapor deposition(CVD)and integrated with a tapered optical fiber to achieve mode-locking in an erbium-doped fiber laser(EDFL)and a thu-lium-doped fiber laser(TDFL).The mode-locked EDFL exhibited a pulse width of 678 fs and an output power of 3.92 mW.The pulse width of mode-locked TDFL was estimated to have a pulse width of 694 fs with an output power of 21.64 mW.These results demonstrate that NiTe_(2)is an effective saturable absorber material with potential applica-tions in the field of ultrafast optics.展开更多
Transition metal disulfides are widely applied as nonlinear optical materials for laser pulse generation.In this paper,TaS_(2)is successfully used for the first time to achieve a high-energy passively Q-switched erbiu...Transition metal disulfides are widely applied as nonlinear optical materials for laser pulse generation.In this paper,TaS_(2)is successfully used for the first time to achieve a high-energy passively Q-switched erbium-doped fiber(EDF)laser.TaS_(2)nanosheets are prepared by the liquid phase exfoliation method,and then the TaS_(2)solution is mixed with polyvinyl alcohol(PVA).TaS_(2)/PVA film is prepared,which is cut into 1 mm×1 mm flakes.TaS_(2)/PVA saturable absorber(SA)is obtained by sandwiching a small flake between two fiber optic patch cable connectors.With the TaS_(2)/PVA SA added to an EDF laser,a Q-switched fiber laser with a center wavelength of 1560 nm and a repetition rate ranging from 51.33 k Hz to 83.04 k Hz is realized.At the pump power of 231 m W,the maximum output power is 1094μW,and the shortest pulse duration is 3.48μs.The results confirm that the TaS_(2)material has excellent potential for application in nonlinear optics.展开更多
A multi-wavelength and transversely mode-switchable fiber laser based on a ring-core fiber Bragg grating(RCFBG) is proposed. Two RCFBGs with high and low reflectivity are inscribed using a femtosecond laser and the ph...A multi-wavelength and transversely mode-switchable fiber laser based on a ring-core fiber Bragg grating(RCFBG) is proposed. Two RCFBGs with high and low reflectivity are inscribed using a femtosecond laser and the phase mask scanning technique, serving as the mirrors in an all-fiber laser linear resonator. Leveraging the polarization dependence of the RCFBG through side exposure, we can readily achieve switchable single-wavelength, dual-wavelength, or triple-wavelength laser outputs by adjusting the polarization controller(PC) inside the resonator. Additionally, three distinct modes, namely, cylindrical vector beam(CVB), fundamental and mixed modes, are successfully obtained in single-wavelength laser operation.Azimuthally or radially polarized lasers can be realized by tuning two PCs inside and outside the resonator while operating in CVB mode. This innovative multi-wavelength and transversely mode-switchable fiber laser based on RCFBGs holds significant potential for applications in wavelength division multiplexing and mode division multiplexing systems.展开更多
Compact and robust wavelength-tunable mid-infrared fiber lasers are urgently needed in the fields of spectroscopic sensing,polymer processing,and free-space communications.In this work,we experimentally reported a hig...Compact and robust wavelength-tunable mid-infrared fiber lasers are urgently needed in the fields of spectroscopic sensing,polymer processing,and free-space communications.In this work,we experimentally reported a high-power wavelength-tunable Er^(3+)/Dy^(3+)codoped fluoride fiber laser by diode clad pumping at 974 nm.Adopting a ruled diffraction grating,the laser wavelength could be continuously tuned in the region of 2854 nm-3510 nm(656 nm)based on the ^(6)H_(13/2)→^(6)H_(15/2)transition of Dy^(3+),where 3510 nm represented the longest wavelength achieved from a Dy^(3+)-doped fluoride fiber laser.Within the wide range of 3018 nm-3331 nm(312 nm),the output power was always kept at>1 W,with the maximum power of 1.75 W obtained at 3181 nm.To the best of our knowledge,this is the first watt-level wavelength-tunable fiber laser in the region of>3μm.Further scaling the power and expanding the tuning range are expected by increasing the pump power while protecting the pumped fiber end.展开更多
Recently, Bi_(4)Br_(4) is proved to be a member of topological insulators and is expected to be a promising candidate for ultrafast photonic device. However, experimental studies on the nonlinear optical properties of...Recently, Bi_(4)Br_(4) is proved to be a member of topological insulators and is expected to be a promising candidate for ultrafast photonic device. However, experimental studies on the nonlinear optical properties of Bi_(4)Br_(4) are limited, and its broadband absorption capabilities have not been validated. This study presents the first preparation of Bi_(4)Br_(4) samples using the chemical vapor transport method, resulting in a saturable absorber(SA) with a high modulation depth(46.23%) and low non-saturable loss(6.5%). The optical nonlinearity ranks among the best in similar studies. Additionally, this work applies Bi_(4)Br_(4)-SA for the first time in 1-μm fiber laser, developing a ring-cavity mode-locked fiber laser with a central wavelength of 1029.79 nm, a pulse duration of 442 fs, and a maximum output power of 90.83 m W. And a linear-cavity mode-locked fiber laser with a central wavelength of 1031.24 nm, a pulse duration of 511 fs, and a maximum output power of 92.81 m W is constructed. It is worth noting that the optical-to-optical conversion efficiency has reached about 11.54% and 33.58%.This study verifies Bi_(4)Br_(4)-SA's modulation effectiveness for 1-μm pulse lasers and provides a powerful reference for the design of high-efficiency fiber lasers.展开更多
Based on the nonlinear saturable absorption properties(NSAPs)of a two-dimensional(2D)material of antimony selenide(Sb_(2)Se_(3)),a Q-switched erbium-doped fiber(EDF)laser is systematically demonstrated.The Sb_(2)Se_(3...Based on the nonlinear saturable absorption properties(NSAPs)of a two-dimensional(2D)material of antimony selenide(Sb_(2)Se_(3)),a Q-switched erbium-doped fiber(EDF)laser is systematically demonstrated.The Sb_(2)Se_(3)nano sheets are prepared by liquid-phase exfoliation(LPE)method.After the sandwich-structured Sb_(2)Se_(3)saturable absorber(SA)is fabricated,the NSAPs are characterized and the modulation depth,the saturation intensity and the unsaturated loss are determined to be 25.2%,2.02 MW/cm^(2),and 3.29%,respectively.When the as-prepared Sb_(2)Se_(3)-SA is integrated into the ring cavity,the laser operates at a stable Q-switching regime in the pump power range of 100—400 mW.The laser oscillates at the central wavelength of 1558.48 nm with a 3 dB bandwidth of 2.32 nm.Take the advantages of the Sb_(2)Se_(3)-SA,the pulse duration can be compressed from 40.49 kHz to 128.12 kHz.At the pump power of 400 mW,the Q-switching laser gives the narrowest pulse duration the highest average output power,the largest pulse energy,and the signal-to-noise ratio(SNR)of 0.93μs,2.16 mW,16.89 nJ,and 53 dB,respectively.Our new attempt on Sb_(2)Se_(3)-based Q-switched EDF laser,combining the existing mode-locking achievements,proves that Sb_(2)Se_(3)is a powerful candidate for pulse compression due to the characteristics of high modulation depth and high stability.展开更多
A dual-wavelength ring-cavity erbium-doped fiber(EDF)laser is designed based on two polarization beam splitters(PBSs)and a polarization controller(PC)performing gain equalization and polarization hole burning(PHB)effe...A dual-wavelength ring-cavity erbium-doped fiber(EDF)laser is designed based on two polarization beam splitters(PBSs)and a polarization controller(PC)performing gain equalization and polarization hole burning(PHB)effect.At room temperature,a stable dual-wavelength laser and a multi-output port laser which can simultaneously emit single-wavelength lasing and dual-wavelength lasing are obtained.The signal-to-noise ratios(SNRs)for single-wavelength outputs were 54.70 dB and 57.10 dB,with power fluctuations less than 0.038 mW and 0.029 mW,respectively.For dual-wavelength lasing,the SNRs were 59.63 dB and 59.25 dB,with power fluctuations less than 0.018 mW and 0.008 mW,respectively.The center wavelength drift was less than 0.006 nm for both single-wavelength and dual-wavelength outputs.展开更多
Soliton molecules(SMs),bounded and self-assembled of particle-like dissipative solitons,exist with versatile mutual interactions and manifest substantial potential in soliton communication and optical data storage.How...Soliton molecules(SMs),bounded and self-assembled of particle-like dissipative solitons,exist with versatile mutual interactions and manifest substantial potential in soliton communication and optical data storage.However,controllable manipulation of the bounded molecular patterns remains challenging,as reaching a specific operation regime in lasers generally involves adjusting multiple control parameters in connection with a wide range of accessible pulse dynamics.An evolutionary algorithm is implemented for intelligent control of SMs in a 2μm ultrafast fiber laser mode locked through nonlinear polarization rotation.Depending on the specifications of the merit function used for the optimization procedure,various SM operations are obtained,including spectra shape programming and controllable deterministic switching of doublet and triplet SMs operating in stationary or pulsation states with reconfigurable temporal separations,frequency locking of pulsation SMs,doublet and SM complexes with controllable pulsation ratio,etc.Digital encoding is further demonstrated in this platform by employing the self-assembled characteristics of SMs.Our work opens up an avenue for active SM control beyond conventional telecom bands and brings useful insights into nonlinear science and applications.展开更多
After a half century of development, fiber laser has evolved from a concept to a great family penetrating into various fields of applications. This paper reviews the history and current development of fiber lasers, wi...After a half century of development, fiber laser has evolved from a concept to a great family penetrating into various fields of applications. This paper reviews the history and current development of fiber lasers, with topics covering both continuous wave and short pulse fiber lasers. Important issues such as the major rare earth dopants, fiber laser brightness, polarization effects, clad pumping technology, beam combination, mode locking and pulse shaping are discussed in this paper.展开更多
A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity ...A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity configuration, featuring multiwavelength output with wavelength interval of double Brillouin frequency shifts. Through simultaneously injecting the BP light and its first-order stimulated Brillouin-scattered light into the cavity, the laser output exhibits a wavelength interval of single Brillouin frequency shift. The wavelength-interval switching effect can be manipulated by controlling the power of the first-order stimulated Brillouin scattering light. The experimental results show the multiwavelength output can be switched between double Brillouin frequency shift multiwavelength emission with a broad bandwidth of approximately 60 nm and single Brillouin frequency shift multiwavelength emission of 44 nm. The flexible optically controlled random fiber laser with switchable wavelength interval makes it useful for a wide range of applications and holds significant potential in the field of wavelength-division multiplexing optical communication.展开更多
In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method wa...In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method was utilized to prepare Nb_(4)AlC_(3)nanosheets,and then a piece of tapered fiber was adopted to fabricate Nb_(4)AlC_(3)-SA.It was found that the saturation intensity and modulation depth of the Nb_(4)AlC_(3)-SA are 2.02 MW/cm^(2)and 1.88%.Based on the Nb_(4)AlC_(3)-SA,a conventional soliton(CS)mode-locked EDF laser was achieved.The central wavelength,pulse duration,and pulse repetition rate were found to be 1565.65 nm,615.37 fs,and 24.63 MHz,respectively.The performance is competitive and particularly superior in terms of pulse duration.This study fully confirms that Nb_(4)AlC_(3)possesses marvellous nonlinear saturable absorption properties and opens new possibilities for further research on air-stable ultrafast photon-ic devices.展开更多
In order to decrease the metallurgical porosity and keyhole-induced porosity during deep penetration laser welding of Al and its alloys, and increase the mechanical properties of work-piece, the effects of welding par...In order to decrease the metallurgical porosity and keyhole-induced porosity during deep penetration laser welding of Al and its alloys, and increase the mechanical properties of work-piece, the effects of welding parameters such as laser power, welding speed and defocusing value on both kinds of porosities were systemically analyzed respectively, and the shape and fluctuation of plume of the keyhole were observed to reflect the stability of the keyhole. The results show that increasing laser power or decreasing laser spot size can lead to the rising of both number and occupied area of pores in the weld; meanwhile, the plume fluctuates violently over the keyhole, which is always companied with the intense metallic vapor, liquid metal spatter and collapsing in the keyhole, thus more pores are generated in the weld. The porosity in the weld reaches the minimum at welding velocity of 2.0 m/min when laser power is 5 kW and defocusing value is 0.展开更多
Stitch welding of plate covered skeleton structure of Ti-6Al-4V titanium alloys has a variety of applications in aerospace vehicle manufacture. The laser stitch welding of Ti-6Al-4V titanium alloys was carried out by ...Stitch welding of plate covered skeleton structure of Ti-6Al-4V titanium alloys has a variety of applications in aerospace vehicle manufacture. The laser stitch welding of Ti-6Al-4V titanium alloys was carried out by a 4 kW ROFIN fiber laser. Influences of laser welding parameters on the macroscopic geometry, porosity, microstructure and mechanical properties of the stitch welded seams were investigated by digital microscope, optical microscope, scanning electron microscope and universal tensile testing machine. The results showed that the three-pipe nozzle with gas flow rate larger than 5 L/min could avoid oxidization, presenting better shielding effect in comparison with the single-pipe nozzle. Porosity formation could be suppressed with the gap between plate and skeleton less than 0.1 mm, while the existing porosity can be reduced with remelting. The maximum shear strength of stitch welding joint with minimal porosity was obtained by employing laser power of 1700 W, welding speed of 1.5 m/min and defocusing distance of ＋8 ram.展开更多
In this paper, we report that a diode-pumped thulium-doped double clad silica fiber laser can provide powers of up to 227 W at 1908 nm, corresponding to a slope efficiency of 54.3%, and an optical-to-optical efficienc...In this paper, we report that a diode-pumped thulium-doped double clad silica fiber laser can provide powers of up to 227 W at 1908 nm, corresponding to a slope efficiency of 54.3%, and an optical-to-optical efficiency of 51.2%. The output power, to the best of our knowledge, is the highest output at 1908 nm. The beam quality M2 factor is about 1.56. Also discussed in this paper is the dependence of the laser performance on fiber length.展开更多
A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100...A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.展开更多
We experimentally demonstrated a stable multi-wavelength bright-dark pulse pair in a mode-locked thulium-doped fiber laser(TDFL).The nonlinear polarization rotation(NPR)and nonlinear optical loop mirror(NOLM)were empl...We experimentally demonstrated a stable multi-wavelength bright-dark pulse pair in a mode-locked thulium-doped fiber laser(TDFL).The nonlinear polarization rotation(NPR)and nonlinear optical loop mirror(NOLM)were employed in a figure-eight cavity to allow for multi-wavelength mode-locking operation.By incorporating different lengths of high birefringence polarization-maintaining fiber(PMF),the fiber laser could operate stably in a multi-wavelength emission state.Compared with the absence of the PMF,the birefringence effect caused by PMF resulted in rich multi-wavelength optical spectra and better intensity symmetry and stability of the bright-dark pulse pair.展开更多
Two-dimensional（2D） materials have been regarded as a promising nonlinear optical medium for fabricating versatile optical and optoelectronic devices. Among the various photonic applications, the employment of 2D ma...Two-dimensional（2D） materials have been regarded as a promising nonlinear optical medium for fabricating versatile optical and optoelectronic devices. Among the various photonic applications, the employment of 2D materials as nonlinear optical devices such as saturable absorbers for ultrashort pulse generation and shaping in ultrafast lasers is one of the most striking aspects in recent years. In this paper, we review the recent progress of 2D materials based pulse generation and soliton shaping in ultrafast fiber lasers, and particularly in the context of 2D materials-decorated microfiber photonic devices. The fabrication of 2D materials-decorated microfiber photonic devices, high performance mode-locked pulse generation, and the nonlinear soliton dynamics based on pulse shaping method are discussed. Finally, the challenges and the perspective of the 2D materials-based photonic devices as well as their applications are also discussed.展开更多
基金supported by the Natural Science Foundation of Guangdong Province (No.2023A1515010093)the Shenzhen Fundamental Research Program (Nos.JCYJ20220809170611004, JCYJ20231121110828001 and JCYJ20231121113641002)。
文摘Due to their unique physical properties,nonlinear materials are gradually demonstrating significant potential in the field of optics.Gold nanoparticles supported on carbon black(Au/CB),possessing low loss and high nonlinear characteristics,serve as an excellent material for saturable absorber(SA) in ultrafast fiber lasers.In this study,we investigated the performance of Au/CB material and designed an ultrafast fiber laser based on Au/CB SA,successfully observing stable fundamental mode-locking and pulse bunch phenomena.Specifically,when the fiber laser operates in fundamental mode-locking state,the center wavelength of optical spectrum is 1 558.82 nm,with a 3 dB bandwidth of 2.26 nm.Additionally,to investigate the evolution of real-time spectra,the dispersive Fourier transform(DFT) technology is employed.On the other hand,the pulse bunch emitted by the laser is actually composed of numerous random sub-pulses,exhibiting high-energy characteristics.The number of sub-pulses increases with the increase of pump power.These findings contribute to further exploring the properties of Au/CB material and reveal its potential applications in ultrafast optics.
基金supported by the National Natural Science Foundation of China(Grant No.12475008)the Scientific Research and Developed Fund of Zhejiang A&F University(Grant No.2021FR0009)。
文摘This study systematically investigates the attractor characteristics of harmonic solitons in a passively modelocked fiber laser.Through comprehensive analysis in both time and frequency domains,we examine the evolution of pulse width,spectral bandwidth,and energy across different harmonic orders.The results demonstrate typical soliton attractor behaviors,including attractiveness,dissipativity,and self-organization.In the transition regions between harmonic orders,breathing harmonic soliton states are captured using the time-stretched dispersive Fourier transform.By comparing the breathing dynamics with the stable states,the existence and self-organizing nature of soliton attractors are further confirmed.Finally,harmonic soliton attractors are employed as programmable light sources to achieve ternary optical coding.
基金supported by the Key Project of Science and Technology Research Program of Hubei Provincial Department of Education,China(D20231704)the Opening Foundation of Hubei Key Laboratory for New Textile Materials and Applications Research(FZXCL202410)the Wuhan Textile University Special Fund Project。
文摘Currently,the performance,cost,and environmental sustainability of saturable absorbers(SAs)represent major bottlenecks in the development of ultrafast fiber lasers.However,the development of high-performance SAs remains challenging due to intricate fabrication processes and inadequate nonlinear performance.In this context,this work presents the natural alkaloid berberine as a promising alternative for mode-locked erbium-doped fiber lasers.The berberine-based SA exhibits excellent nonlinear optical properties,including a modulation depth of 24.40%and a saturation intensity of 1.281MW/cm^(2),and successfully enables stable femtosecond pulse generation.By employing time-stretched dispersive Fourier transform technology,the transient dynamics results indicate that the berberine-based SA significantly shortens the relaxation oscillation time and effectively suppresses pulse intensity fluctuations,thereby accelerating the self-starting process of mode-locking.This work provides a new strategy for developing high-performance,low-cost,and environmentally friendly ultrafast photonic devices,significantly advancing the practical application of green SAs.
基金Supported by Guangdong Basic and Applied Basic Research Fund,China(2024A1515012429)。
文摘As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ener-gy,biomedicine,optoelectronic devices,and so on.At present,there have been scant reports on the application of NiTe_(2)in the field of ultrafast photonics.In this work,NiTe_(2)was synthesized by chemical vapor deposition(CVD)and integrated with a tapered optical fiber to achieve mode-locking in an erbium-doped fiber laser(EDFL)and a thu-lium-doped fiber laser(TDFL).The mode-locked EDFL exhibited a pulse width of 678 fs and an output power of 3.92 mW.The pulse width of mode-locked TDFL was estimated to have a pulse width of 694 fs with an output power of 21.64 mW.These results demonstrate that NiTe_(2)is an effective saturable absorber material with potential applica-tions in the field of ultrafast optics.
基金Project supported by the National Natural Science Foundation of China(Grant No.12075190)the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.23JSY019)。
文摘Transition metal disulfides are widely applied as nonlinear optical materials for laser pulse generation.In this paper,TaS_(2)is successfully used for the first time to achieve a high-energy passively Q-switched erbium-doped fiber(EDF)laser.TaS_(2)nanosheets are prepared by the liquid phase exfoliation method,and then the TaS_(2)solution is mixed with polyvinyl alcohol(PVA).TaS_(2)/PVA film is prepared,which is cut into 1 mm×1 mm flakes.TaS_(2)/PVA saturable absorber(SA)is obtained by sandwiching a small flake between two fiber optic patch cable connectors.With the TaS_(2)/PVA SA added to an EDF laser,a Q-switched fiber laser with a center wavelength of 1560 nm and a repetition rate ranging from 51.33 k Hz to 83.04 k Hz is realized.At the pump power of 231 m W,the maximum output power is 1094μW,and the shortest pulse duration is 3.48μs.The results confirm that the TaS_(2)material has excellent potential for application in nonlinear optics.
基金Project supported by the National Natural Science Foundation of China (Grant No. 62075182)the National Key Research and Development Program of China (Grant No. 2022YFB3207502)。
文摘A multi-wavelength and transversely mode-switchable fiber laser based on a ring-core fiber Bragg grating(RCFBG) is proposed. Two RCFBGs with high and low reflectivity are inscribed using a femtosecond laser and the phase mask scanning technique, serving as the mirrors in an all-fiber laser linear resonator. Leveraging the polarization dependence of the RCFBG through side exposure, we can readily achieve switchable single-wavelength, dual-wavelength, or triple-wavelength laser outputs by adjusting the polarization controller(PC) inside the resonator. Additionally, three distinct modes, namely, cylindrical vector beam(CVB), fundamental and mixed modes, are successfully obtained in single-wavelength laser operation.Azimuthally or radially polarized lasers can be realized by tuning two PCs inside and outside the resonator while operating in CVB mode. This innovative multi-wavelength and transversely mode-switchable fiber laser based on RCFBGs holds significant potential for applications in wavelength division multiplexing and mode division multiplexing systems.
基金supported in parts by the National Natural Science Foundation of China under Grant No.62475035.
文摘Compact and robust wavelength-tunable mid-infrared fiber lasers are urgently needed in the fields of spectroscopic sensing,polymer processing,and free-space communications.In this work,we experimentally reported a high-power wavelength-tunable Er^(3+)/Dy^(3+)codoped fluoride fiber laser by diode clad pumping at 974 nm.Adopting a ruled diffraction grating,the laser wavelength could be continuously tuned in the region of 2854 nm-3510 nm(656 nm)based on the ^(6)H_(13/2)→^(6)H_(15/2)transition of Dy^(3+),where 3510 nm represented the longest wavelength achieved from a Dy^(3+)-doped fluoride fiber laser.Within the wide range of 3018 nm-3331 nm(312 nm),the output power was always kept at>1 W,with the maximum power of 1.75 W obtained at 3181 nm.To the best of our knowledge,this is the first watt-level wavelength-tunable fiber laser in the region of>3μm.Further scaling the power and expanding the tuning range are expected by increasing the pump power while protecting the pumped fiber end.
基金Project supported by the Beijing Natural Science Foundation (Grant No. JQ21019)the National Key Research and Development Program of China (Grant Nos. 2022YFA1604200 and 2022YFA1204100)the Fund from Beijing Municipal Commission of Science and Technology (Grant No. Z231100006623006)。
文摘Recently, Bi_(4)Br_(4) is proved to be a member of topological insulators and is expected to be a promising candidate for ultrafast photonic device. However, experimental studies on the nonlinear optical properties of Bi_(4)Br_(4) are limited, and its broadband absorption capabilities have not been validated. This study presents the first preparation of Bi_(4)Br_(4) samples using the chemical vapor transport method, resulting in a saturable absorber(SA) with a high modulation depth(46.23%) and low non-saturable loss(6.5%). The optical nonlinearity ranks among the best in similar studies. Additionally, this work applies Bi_(4)Br_(4)-SA for the first time in 1-μm fiber laser, developing a ring-cavity mode-locked fiber laser with a central wavelength of 1029.79 nm, a pulse duration of 442 fs, and a maximum output power of 90.83 m W. And a linear-cavity mode-locked fiber laser with a central wavelength of 1031.24 nm, a pulse duration of 511 fs, and a maximum output power of 92.81 m W is constructed. It is worth noting that the optical-to-optical conversion efficiency has reached about 11.54% and 33.58%.This study verifies Bi_(4)Br_(4)-SA's modulation effectiveness for 1-μm pulse lasers and provides a powerful reference for the design of high-efficiency fiber lasers.
基金supported by the National Natural Science Foundation of China(No.11304184)the Shandong University of Technology and Zibo City Integration Development Project(No.2019ZBXC120)。
文摘Based on the nonlinear saturable absorption properties(NSAPs)of a two-dimensional(2D)material of antimony selenide(Sb_(2)Se_(3)),a Q-switched erbium-doped fiber(EDF)laser is systematically demonstrated.The Sb_(2)Se_(3)nano sheets are prepared by liquid-phase exfoliation(LPE)method.After the sandwich-structured Sb_(2)Se_(3)saturable absorber(SA)is fabricated,the NSAPs are characterized and the modulation depth,the saturation intensity and the unsaturated loss are determined to be 25.2%,2.02 MW/cm^(2),and 3.29%,respectively.When the as-prepared Sb_(2)Se_(3)-SA is integrated into the ring cavity,the laser operates at a stable Q-switching regime in the pump power range of 100—400 mW.The laser oscillates at the central wavelength of 1558.48 nm with a 3 dB bandwidth of 2.32 nm.Take the advantages of the Sb_(2)Se_(3)-SA,the pulse duration can be compressed from 40.49 kHz to 128.12 kHz.At the pump power of 400 mW,the Q-switching laser gives the narrowest pulse duration the highest average output power,the largest pulse energy,and the signal-to-noise ratio(SNR)of 0.93μs,2.16 mW,16.89 nJ,and 53 dB,respectively.Our new attempt on Sb_(2)Se_(3)-based Q-switched EDF laser,combining the existing mode-locking achievements,proves that Sb_(2)Se_(3)is a powerful candidate for pulse compression due to the characteristics of high modulation depth and high stability.
基金supported by the Key Scientific Research Project of Hunan Education Department,China(No.23A0446)the Natural Science Foundation of Hunan Province,China(provinces and cities combined)(No.2022JJ50067)+1 种基金the Hunan Province Degree and Postgraduate Teaching Reform Research Project,China(No.2022JGYB182)the Scientific Research and Innovation Foundation of Hunan University of Technology(No.CX2314).
文摘A dual-wavelength ring-cavity erbium-doped fiber(EDF)laser is designed based on two polarization beam splitters(PBSs)and a polarization controller(PC)performing gain equalization and polarization hole burning(PHB)effect.At room temperature,a stable dual-wavelength laser and a multi-output port laser which can simultaneously emit single-wavelength lasing and dual-wavelength lasing are obtained.The signal-to-noise ratios(SNRs)for single-wavelength outputs were 54.70 dB and 57.10 dB,with power fluctuations less than 0.038 mW and 0.029 mW,respectively.For dual-wavelength lasing,the SNRs were 59.63 dB and 59.25 dB,with power fluctuations less than 0.018 mW and 0.008 mW,respectively.The center wavelength drift was less than 0.006 nm for both single-wavelength and dual-wavelength outputs.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region of China(Grant Nos.HKU 17212824,HKU 17210522,HKU C7074-21G,HKU R7003-21,and HKU 17205321)the Innovation and Technology Commission of the Hong Kong SAR Government(Grant Nos.MHP/073/20 and MHP/057/21),and the Health@InnoHK program.
文摘Soliton molecules(SMs),bounded and self-assembled of particle-like dissipative solitons,exist with versatile mutual interactions and manifest substantial potential in soliton communication and optical data storage.However,controllable manipulation of the bounded molecular patterns remains challenging,as reaching a specific operation regime in lasers generally involves adjusting multiple control parameters in connection with a wide range of accessible pulse dynamics.An evolutionary algorithm is implemented for intelligent control of SMs in a 2μm ultrafast fiber laser mode locked through nonlinear polarization rotation.Depending on the specifications of the merit function used for the optimization procedure,various SM operations are obtained,including spectra shape programming and controllable deterministic switching of doublet and triplet SMs operating in stationary or pulsation states with reconfigurable temporal separations,frequency locking of pulsation SMs,doublet and SM complexes with controllable pulsation ratio,etc.Digital encoding is further demonstrated in this platform by employing the self-assembled characteristics of SMs.Our work opens up an avenue for active SM control beyond conventional telecom bands and brings useful insights into nonlinear science and applications.
文摘After a half century of development, fiber laser has evolved from a concept to a great family penetrating into various fields of applications. This paper reviews the history and current development of fiber lasers, with topics covering both continuous wave and short pulse fiber lasers. Important issues such as the major rare earth dopants, fiber laser brightness, polarization effects, clad pumping technology, beam combination, mode locking and pulse shaping are discussed in this paper.
基金Poject supported by the National Natural Science Foundation of China(Grant Nos.62175116 and 62311530343)the Postgraduate Research Innovation Program of Jiangsu Province,China(Grant No.KYCX22_0913)。
文摘A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity configuration, featuring multiwavelength output with wavelength interval of double Brillouin frequency shifts. Through simultaneously injecting the BP light and its first-order stimulated Brillouin-scattered light into the cavity, the laser output exhibits a wavelength interval of single Brillouin frequency shift. The wavelength-interval switching effect can be manipulated by controlling the power of the first-order stimulated Brillouin scattering light. The experimental results show the multiwavelength output can be switched between double Brillouin frequency shift multiwavelength emission with a broad bandwidth of approximately 60 nm and single Brillouin frequency shift multiwavelength emission of 44 nm. The flexible optically controlled random fiber laser with switchable wavelength interval makes it useful for a wide range of applications and holds significant potential in the field of wavelength-division multiplexing optical communication.
文摘In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method was utilized to prepare Nb_(4)AlC_(3)nanosheets,and then a piece of tapered fiber was adopted to fabricate Nb_(4)AlC_(3)-SA.It was found that the saturation intensity and modulation depth of the Nb_(4)AlC_(3)-SA are 2.02 MW/cm^(2)and 1.88%.Based on the Nb_(4)AlC_(3)-SA,a conventional soliton(CS)mode-locked EDF laser was achieved.The central wavelength,pulse duration,and pulse repetition rate were found to be 1565.65 nm,615.37 fs,and 24.63 MHz,respectively.The performance is competitive and particularly superior in terms of pulse duration.This study fully confirms that Nb_(4)AlC_(3)possesses marvellous nonlinear saturable absorption properties and opens new possibilities for further research on air-stable ultrafast photon-ic devices.
基金Project(51204109)supported by the National Natural Science Foundation of China
文摘In order to decrease the metallurgical porosity and keyhole-induced porosity during deep penetration laser welding of Al and its alloys, and increase the mechanical properties of work-piece, the effects of welding parameters such as laser power, welding speed and defocusing value on both kinds of porosities were systemically analyzed respectively, and the shape and fluctuation of plume of the keyhole were observed to reflect the stability of the keyhole. The results show that increasing laser power or decreasing laser spot size can lead to the rising of both number and occupied area of pores in the weld; meanwhile, the plume fluctuates violently over the keyhole, which is always companied with the intense metallic vapor, liquid metal spatter and collapsing in the keyhole, thus more pores are generated in the weld. The porosity in the weld reaches the minimum at welding velocity of 2.0 m/min when laser power is 5 kW and defocusing value is 0.
基金Project(2012BAF08B02)supported by Key Project in the National Science and Technology Pillar Program During the Twelfth Five-year Plan Period,China
文摘Stitch welding of plate covered skeleton structure of Ti-6Al-4V titanium alloys has a variety of applications in aerospace vehicle manufacture. The laser stitch welding of Ti-6Al-4V titanium alloys was carried out by a 4 kW ROFIN fiber laser. Influences of laser welding parameters on the macroscopic geometry, porosity, microstructure and mechanical properties of the stitch welded seams were investigated by digital microscope, optical microscope, scanning electron microscope and universal tensile testing machine. The results showed that the three-pipe nozzle with gas flow rate larger than 5 L/min could avoid oxidization, presenting better shielding effect in comparison with the single-pipe nozzle. Porosity formation could be suppressed with the gap between plate and skeleton less than 0.1 mm, while the existing porosity can be reduced with remelting. The maximum shear strength of stitch welding joint with minimal porosity was obtained by employing laser power of 1700 W, welding speed of 1.5 m/min and defocusing distance of ＋8 ram.
文摘In this paper, we report that a diode-pumped thulium-doped double clad silica fiber laser can provide powers of up to 227 W at 1908 nm, corresponding to a slope efficiency of 54.3%, and an optical-to-optical efficiency of 51.2%. The output power, to the best of our knowledge, is the highest output at 1908 nm. The beam quality M2 factor is about 1.56. Also discussed in this paper is the dependence of the laser performance on fiber length.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Natural Science Foundation of Guangdong Province under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the ’Cross and Cooperative’ Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.
基金the National Natural Science Foundation of China(Grant No.6170031626)the Natural Science Foundation of Chongqing City,China(Grant Nos.cstc2018jcyjAX0585 and cstc2017zdzxX0011).
文摘We experimentally demonstrated a stable multi-wavelength bright-dark pulse pair in a mode-locked thulium-doped fiber laser(TDFL).The nonlinear polarization rotation(NPR)and nonlinear optical loop mirror(NOLM)were employed in a figure-eight cavity to allow for multi-wavelength mode-locking operation.By incorporating different lengths of high birefringence polarization-maintaining fiber(PMF),the fiber laser could operate stably in a multi-wavelength emission state.Compared with the absence of the PMF,the birefringence effect caused by PMF resulted in rich multi-wavelength optical spectra and better intensity symmetry and stability of the bright-dark pulse pair.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61307058,61378036,11304101,and 11474108)Guangdong Natural Science Funds for Distinguished Young Scholar,China(Grant No.2014A030306019)+6 种基金Pearl River S&T Nova Program of Guangzhou,China(Grant No.2014J2200008)Program for Outstanding Innovative Young Talents of Guangdong Province,China(Grant No.2014TQ01X220)Program for Outstanding Young Teachers in Guangdong Higher Education Institutes,China(Grant No.YQ2015051)Science and Technology Project of Guangdong,China(Grant No.2016B090925004)Foundation for Young Talents in Higher Education of Guangdong,China(Grant No.2017KQNCX051)Science and Technology Program of Guangzhou,China(Grant No.201607010245)Scientific Research Foundation of Young Teacher of South China Normal University,China(Grant No.17KJ09)
文摘Two-dimensional（2D） materials have been regarded as a promising nonlinear optical medium for fabricating versatile optical and optoelectronic devices. Among the various photonic applications, the employment of 2D materials as nonlinear optical devices such as saturable absorbers for ultrashort pulse generation and shaping in ultrafast lasers is one of the most striking aspects in recent years. In this paper, we review the recent progress of 2D materials based pulse generation and soliton shaping in ultrafast fiber lasers, and particularly in the context of 2D materials-decorated microfiber photonic devices. The fabrication of 2D materials-decorated microfiber photonic devices, high performance mode-locked pulse generation, and the nonlinear soliton dynamics based on pulse shaping method are discussed. Finally, the challenges and the perspective of the 2D materials-based photonic devices as well as their applications are also discussed.
