Development of a high power fiber laser at special waveband,which is difficult to achieve by conventional rare-earth-doped fibers,is a significant challenge.One of the most common methods for achieving lasing at speci...Development of a high power fiber laser at special waveband,which is difficult to achieve by conventional rare-earth-doped fibers,is a significant challenge.One of the most common methods for achieving lasing at special wavelength is Raman conversion.Phosphorus-doped fiber(PDF),due to the phosphorus-related large frequency shift Raman peak at 40 THz,is a great choice for large frequency shift Raman conversion.Here,by adopting 150 m large mode area triple-clad PDF as Raman gain medium,and a novel wavelength-selective feedback mechanism to suppress the silica-related Raman emission,we build a high power cladding-pumped Raman fiber laser at 1.2μm waveband.A Raman signal with power up to 735.8 W at 1252.7 nm is obtained.To the best of our knowledge,this is the highest output power ever reported for fiber lasers at 1.2μm waveband.Moreover,by tuning the wavelength of the pump source,a tunable Raman output of more than 450 W over a wavelength range of 1240.6–1252.7 nm is demonstrated.This work proves PDF’s advantage in high power large frequency shift Raman conversion with a cladding pump scheme,thus providing a good solution for a high power laser source at special waveband.展开更多
A spectral programmable,continuous-wave mid-infrared(MIR)optical parametric oscillator(OPO),enabled by a self-developed high-power spectral tailorable fiber laser,was proposed and realized.While operating at a singlew...A spectral programmable,continuous-wave mid-infrared(MIR)optical parametric oscillator(OPO),enabled by a self-developed high-power spectral tailorable fiber laser,was proposed and realized.While operating at a singlewavelength,the maximum idler power reached 5.53 W at 3028 nm,with a corresponding pump-to-idler conversion efficiency of 14.7%.The wavelength number switchable output was available from one to three.The single idler was tunable in a range of 528 nm(2852–3380 nm).In a dual-wavelength operation,the interval between two idlers could be flexibly tuned for 470 nm(53–523 nm),and the intensity of each channel was controllable.Triplewavelength idler emission was realized,meanwhile exhibiting spectral custom-tailored characteristics.Furthermore,we balanced the parametric gain through the pre-modulating broadband multi-peak pump spectra,enabling a 10 d B bandwidth adjustment of the idler emission from 20 to 125 nm.This versatile mid-infrared laser,simultaneously featuring wide tuning,multi-wavelength operation,and broad bandwidth manipulation,has great application potential in composition detection,terahertz generation,and speckle-free imaging.展开更多
Heat generated by the quantum defect(QD)in optically pumped lasers can result in detrimental effects such as mode instability,frequency noise,and even catastrophic damage.Previously,we demonstrated that boson-peakbase...Heat generated by the quantum defect(QD)in optically pumped lasers can result in detrimental effects such as mode instability,frequency noise,and even catastrophic damage.Previously,we demonstrated that boson-peakbased Raman fiber lasers have great potential in low QD laser generation.But their power scalability and heat load characteristics have yet to be investigated.Here,we demonstrate a boson-peak-based Raman fiber amplifier(RFA)with 815 W output power and a QD of 1.3%.The low heat generation characteristics of this low QD RFA are demonstrated.Both experimental and simulation results show that at this power level,the heat load of the low QD RFA is significantly lower than that of the conventional RFA with a QD of 4.8%.Thanks to its low heat generation characteristics,the proposed phosphosilicate-fiber-based low QD RFA provides an effective solution for the intractable thermal issue in optically pumped lasers,which is of significance in reducing the laser’s noise,improving the laser’s stability and safety,and solving the challenge of heat removing.展开更多
In past decades,multi-wavelength lasers have attracted much attention due to their wide applications in many fields.In this paper,we demonstrate a multi-wavelength random fiber laser with customizable spectra enabled ...In past decades,multi-wavelength lasers have attracted much attention due to their wide applications in many fields.In this paper,we demonstrate a multi-wavelength random fiber laser with customizable spectra enabled by an acousto–optic tunable filter.The operating wavelength range can be tuned from 1114.5 to 1132.5 nm with a maximal output power of 5.55 W,and spectral channel tuning can also be realized with a maximal number of five.The effect of gain competition and the interaction between Raman gain and insertion loss are also analyzed.Furthermore,the output spectra can be ordered by radiating appropriate radio frequency signals to the acousto–optic tunable filter.This work may provide a reference for agile shape spectrum generation and promote multi-wavelength random fiber laser practicability in sensing,telecommunications,and precise spectroscopy.展开更多
High-power operation is one of the most important research topics surrounding random fiber lasers(RDFLs).Here we optimized the cavity structure and proposed a new scheme based on hybrid gain to address the issue of hi...High-power operation is one of the most important research topics surrounding random fiber lasers(RDFLs).Here we optimized the cavity structure and proposed a new scheme based on hybrid gain to address the issue of high-power backward light in traditional kilowatt-level RDFLs.Consequently,a record power of 1972 W was achieved while the maximum backward leaked power only reached 0.12 W.The conversion efficiency relative to the laser diode pump power was 68.4%,and the highest spectral purity of the random lasing reached 98.1%.This work may provide a reference for high-power RDFLs,Raman fiber lasers,and long-wavelength Yb-doped fiber lasers.展开更多
This paper presents radio frequency(RF)microelectromechanical system(MEMS)filters with extremely high bandwidth widening capability.The proposed filtering topologies include hybrid configurations consisting of piezoel...This paper presents radio frequency(RF)microelectromechanical system(MEMS)filters with extremely high bandwidth widening capability.The proposed filtering topologies include hybrid configurations consisting of piezoelectric MEMS resonators and surface-mounted lumped elements.The MEMS resonators set the center frequency and provide electromechanical coupling to construct the filters,while the lumped-element-based matching networks help widen the bandwidth(BW)and enhance the out-of-band rejection.Aluminum nitride(AlN)S0 Lamb wave resonators are then applied to the proposed filtering topologies.AlN S0 first-and second-order wideband filters are studied and have shown prominent performance.Finally,the AlN S0 first-order wideband filter is experimentally implemented and characterized.The demonstrated first-order filter shows a large fractional bandwidth(FBW)of 5.6%(achieved with a resonator coupling of 0.94%)and a low insertion loss(IL)of 1.84 dB.The extracted bandwidth widening factor(BWF)is 6,which is approximately 12 times higher than those of the current ladder or lattice filtering topologies.This impressive bandwidth widening capability holds great potential for satisfying the stringent BW requirements of bands n77,n78,and n79 of 5G new radio(NR)and will overcome an outstanding technology hurdle in placing 5G NR into the marketplace.展开更多
This study presents a high-accuracy,all-fber mode division multiplexing(MDM)reconstructive spectrometer(RS).The MDM was achieved by utilizing a custom-designed 3×1 mode-selective photonics lantern to launch disti...This study presents a high-accuracy,all-fber mode division multiplexing(MDM)reconstructive spectrometer(RS).The MDM was achieved by utilizing a custom-designed 3×1 mode-selective photonics lantern to launch distinct spatial modes into the multimode fber(MMF).This facilitated the information transmission by increasing light scattering processes,thereby encoding the optical spectra more comprehensively into speckle patterns.Spectral resolution of 2 pm and the recovery of 2000 spectral channels were accomplished.Compared to methods employing single-mode excitation and two-mode excitation,the three-mode excitation method reduced the recovered error by 88%and 50%respectively.A resolution enhancement approach based on alternating mode modulation was proposed,reaching the MMF limit for the 3 dB bandwidth of the spectral correlation function.The proof-of-concept study can be further extended to encompass diverse programmable mode excitations.It is not only succinct and highly efcient but also well-suited for a variety of high-accuracy,high-resolution spectral measurement scenarios.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.61635005,61905284,and 62305391)the National Postdoctoral Program for Innovative Talents(No.BX20190063).
文摘Development of a high power fiber laser at special waveband,which is difficult to achieve by conventional rare-earth-doped fibers,is a significant challenge.One of the most common methods for achieving lasing at special wavelength is Raman conversion.Phosphorus-doped fiber(PDF),due to the phosphorus-related large frequency shift Raman peak at 40 THz,is a great choice for large frequency shift Raman conversion.Here,by adopting 150 m large mode area triple-clad PDF as Raman gain medium,and a novel wavelength-selective feedback mechanism to suppress the silica-related Raman emission,we build a high power cladding-pumped Raman fiber laser at 1.2μm waveband.A Raman signal with power up to 735.8 W at 1252.7 nm is obtained.To the best of our knowledge,this is the highest output power ever reported for fiber lasers at 1.2μm waveband.Moreover,by tuning the wavelength of the pump source,a tunable Raman output of more than 450 W over a wavelength range of 1240.6–1252.7 nm is demonstrated.This work proves PDF’s advantage in high power large frequency shift Raman conversion with a cladding pump scheme,thus providing a good solution for a high power laser source at special waveband.
基金Project 2019-JCJQ(JJ-202)National Postdoctoral Program for Innovative Talents(BX20190063)+1 种基金Hunan Innovative Province Construction Project(2019RS3017)National Natural Science Foundation of China(61975236,62061136013,62035015)。
文摘A spectral programmable,continuous-wave mid-infrared(MIR)optical parametric oscillator(OPO),enabled by a self-developed high-power spectral tailorable fiber laser,was proposed and realized.While operating at a singlewavelength,the maximum idler power reached 5.53 W at 3028 nm,with a corresponding pump-to-idler conversion efficiency of 14.7%.The wavelength number switchable output was available from one to three.The single idler was tunable in a range of 528 nm(2852–3380 nm).In a dual-wavelength operation,the interval between two idlers could be flexibly tuned for 470 nm(53–523 nm),and the intensity of each channel was controllable.Triplewavelength idler emission was realized,meanwhile exhibiting spectral custom-tailored characteristics.Furthermore,we balanced the parametric gain through the pre-modulating broadband multi-peak pump spectra,enabling a 10 d B bandwidth adjustment of the idler emission from 20 to 125 nm.This versatile mid-infrared laser,simultaneously featuring wide tuning,multi-wavelength operation,and broad bandwidth manipulation,has great application potential in composition detection,terahertz generation,and speckle-free imaging.
基金National Postdoctoral Program for Innovative Talents(BX20190063)National Natural Science Foundation of China(61635005,61905284,62305391)。
文摘Heat generated by the quantum defect(QD)in optically pumped lasers can result in detrimental effects such as mode instability,frequency noise,and even catastrophic damage.Previously,we demonstrated that boson-peakbased Raman fiber lasers have great potential in low QD laser generation.But their power scalability and heat load characteristics have yet to be investigated.Here,we demonstrate a boson-peak-based Raman fiber amplifier(RFA)with 815 W output power and a QD of 1.3%.The low heat generation characteristics of this low QD RFA are demonstrated.Both experimental and simulation results show that at this power level,the heat load of the low QD RFA is significantly lower than that of the conventional RFA with a QD of 4.8%.Thanks to its low heat generation characteristics,the proposed phosphosilicate-fiber-based low QD RFA provides an effective solution for the intractable thermal issue in optically pumped lasers,which is of significance in reducing the laser’s noise,improving the laser’s stability and safety,and solving the challenge of heat removing.
基金Hunan Provincial Innovation Foundation for Postgraduate(CX20190006)Special Fund for Hunan Provincial Innovative Province Building(2019RS3017)National Natural Science Foundation of China(61905284).
文摘In past decades,multi-wavelength lasers have attracted much attention due to their wide applications in many fields.In this paper,we demonstrate a multi-wavelength random fiber laser with customizable spectra enabled by an acousto–optic tunable filter.The operating wavelength range can be tuned from 1114.5 to 1132.5 nm with a maximal output power of 5.55 W,and spectral channel tuning can also be realized with a maximal number of five.The effect of gain competition and the interaction between Raman gain and insertion loss are also analyzed.Furthermore,the output spectra can be ordered by radiating appropriate radio frequency signals to the acousto–optic tunable filter.This work may provide a reference for agile shape spectrum generation and promote multi-wavelength random fiber laser practicability in sensing,telecommunications,and precise spectroscopy.
基金supported in part by the National Natural Science Foundation of China (NSFC) (Nos.61635005 and 61905284)the National Postdoctoral Program for Innovative Talents (No.BX20190063)。
文摘High-power operation is one of the most important research topics surrounding random fiber lasers(RDFLs).Here we optimized the cavity structure and proposed a new scheme based on hybrid gain to address the issue of high-power backward light in traditional kilowatt-level RDFLs.Consequently,a record power of 1972 W was achieved while the maximum backward leaked power only reached 0.12 W.The conversion efficiency relative to the laser diode pump power was 68.4%,and the highest spectral purity of the random lasing reached 98.1%.This work may provide a reference for high-power RDFLs,Raman fiber lasers,and long-wavelength Yb-doped fiber lasers.
基金This work was supported by the Science and Technology Commission of Shanghai Municipality(Shanghai Pujiang Program 18PJ1408300)Natural Science Foundation of Shanghai(19ZR1477000)National Science Foundation of China(61874073).
文摘This paper presents radio frequency(RF)microelectromechanical system(MEMS)filters with extremely high bandwidth widening capability.The proposed filtering topologies include hybrid configurations consisting of piezoelectric MEMS resonators and surface-mounted lumped elements.The MEMS resonators set the center frequency and provide electromechanical coupling to construct the filters,while the lumped-element-based matching networks help widen the bandwidth(BW)and enhance the out-of-band rejection.Aluminum nitride(AlN)S0 Lamb wave resonators are then applied to the proposed filtering topologies.AlN S0 first-and second-order wideband filters are studied and have shown prominent performance.Finally,the AlN S0 first-order wideband filter is experimentally implemented and characterized.The demonstrated first-order filter shows a large fractional bandwidth(FBW)of 5.6%(achieved with a resonator coupling of 0.94%)and a low insertion loss(IL)of 1.84 dB.The extracted bandwidth widening factor(BWF)is 6,which is approximately 12 times higher than those of the current ladder or lattice filtering topologies.This impressive bandwidth widening capability holds great potential for satisfying the stringent BW requirements of bands n77,n78,and n79 of 5G new radio(NR)and will overcome an outstanding technology hurdle in placing 5G NR into the marketplace.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant No.62305391)Hunan Innovative Province Construction Project(No.2019RS3017)Scientifc Fund of National University of Defense Technology(No.22-061).
文摘This study presents a high-accuracy,all-fber mode division multiplexing(MDM)reconstructive spectrometer(RS).The MDM was achieved by utilizing a custom-designed 3×1 mode-selective photonics lantern to launch distinct spatial modes into the multimode fber(MMF).This facilitated the information transmission by increasing light scattering processes,thereby encoding the optical spectra more comprehensively into speckle patterns.Spectral resolution of 2 pm and the recovery of 2000 spectral channels were accomplished.Compared to methods employing single-mode excitation and two-mode excitation,the three-mode excitation method reduced the recovered error by 88%and 50%respectively.A resolution enhancement approach based on alternating mode modulation was proposed,reaching the MMF limit for the 3 dB bandwidth of the spectral correlation function.The proof-of-concept study can be further extended to encompass diverse programmable mode excitations.It is not only succinct and highly efcient but also well-suited for a variety of high-accuracy,high-resolution spectral measurement scenarios.
