Femtosecond optical frequency combs correlate the microwave and optical frequencies accurately and coherently.Therefore,any optical frequency in visible to near-infrared region can be directly traced to a microwave fr...Femtosecond optical frequency combs correlate the microwave and optical frequencies accurately and coherently.Therefore,any optical frequency in visible to near-infrared region can be directly traced to a microwave frequency.As a result,the length unit“meter”is directly related to the time unit“second”.This paper validates the capability of the national wavelength standards based on a home-made Er-doped fiber femtosecond optical frequency comb to measure the laser frequencies ranging from visible to near-infrared region.Optical frequency conversion in the femtosecond optical frequency comb is achieved by combining spectral broadening in a highly nonlinear fiber with a single-point frequencydoubling scheme.The signal-to-noise ratio of the beat notes between the femtosecond optical frequency comb and the lasers at 633,698,729,780,1064,and 1542 nm is better than 30 d B.The frequency instability of the above lasers is evaluated by using a hydrogen clock signal with a instability of better than 1×10^(-13)at 1-s averaging time.The measurement is further validated by measuring the absolute optical frequency of an iodine-stabilized 532-nm laser and an acetylenestabilized 1542-nm laser.The results are within the uncertainty range of the international recommended values.Our results demonstrate the accurate optical frequency measurement of lasers at different frequencies using the femtosecond optical frequency comb,which is not only important for the precise and accurate traceability and calibration of the laser frequencies,but also provides technical support for establishing the national wavelength standards based on the femtosecond optical frequency comb.展开更多
To obtain a stable amplified spontaneous emission(ASE) source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperature...To obtain a stable amplified spontaneous emission(ASE) source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.展开更多
Optical dispersive nonlinearities in Er-doped optical fiber are discussed and measured at the third window wavelength 1.55 μm for optical communications firstly. The experimental method, which is developed by us, is ...Optical dispersive nonlinearities in Er-doped optical fiber are discussed and measured at the third window wavelength 1.55 μm for optical communications firstly. The experimental method, which is developed by us, is based on dynamic scanning for fixed-point-interference (DSFPI) of two fiber beams. The real part and complex value of the third-order susceptibility at the wavelength are also obtained from the measured Kerr coefficient and nonlinear-absorption coefficient reported elsewhere.展开更多
We demonstrate a passively harmonic mode-locked(PHML) fiber laser operating at the L-band using carbon nanotubes polyvinyl alcohol(CNTs-PVA) film. Under suitable pump power and an appropriate setting of the polari...We demonstrate a passively harmonic mode-locked(PHML) fiber laser operating at the L-band using carbon nanotubes polyvinyl alcohol(CNTs-PVA) film. Under suitable pump power and an appropriate setting of the polarization controller(PC), the 54^(th) harmonic pulses at the L-band are generated with the side mode suppression ratio(SMSR) better than 44 dB and a repetition frequency of 503.37 MHz. Further increasing the pump power leads to a higher frequency of 550 MHz with compromised stability of 38.5 dB SMSR. To the best of our knowledge, this is the first demonstration on the generation of L-band PHML pulses from an Er-doped fiber laser based on CNTs.展开更多
In this paper, we adopt cloud computing in a specific scientific computing field for its virtualization, distribution and dynamic extendibility as follows: We obtain high-energy parabolic self-similar pulses by numeri...In this paper, we adopt cloud computing in a specific scientific computing field for its virtualization, distribution and dynamic extendibility as follows: We obtain high-energy parabolic self-similar pulses by numerical simulation using our non-distributed passively mode-locked Er-doped fiber laser model. For researching characteristics of these wave-breaking-free self-similar pulses, chirp of them must be extracted. We propose several time-frequency analysis methods adopted in chirp extraction of ultra-short optical pulses for the first time and discuss the advantages and disadvantages of them in this particular application.展开更多
Using the reduced graphene oxide(rGO) as a saturable absorber(SA) in an Er-doped fiber(EDF) laser cavity,we obtain the Q-switching operation. The rGO SA is prepared by depositing the GO on fluorine mica(FM) us...Using the reduced graphene oxide(rGO) as a saturable absorber(SA) in an Er-doped fiber(EDF) laser cavity,we obtain the Q-switching operation. The rGO SA is prepared by depositing the GO on fluorine mica(FM) using the thermal reduction method. The modulation depth of rGO/FM is measured to be 3.2%. By incorporating the rGO/FM film into the EDF laser cavity, we obtain stable Q-switched pulses. The shortest pulse duration is3.53 μs, and the maximum single pulse energy is 48.19 nJ. The long-term stability of working is well exhibited.The experimental results show that the rGO possesses potential photonics applications.展开更多
Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have d...Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have different coupling constants and propagation losses. We calculate the effective pump power absorption ratio along the fiber with different coupling constants from the first cladding to the doped core and with different propagation losses for the power in the inner cladding. Then the gains of the double clad Er-doped fiber amplifiers versus fiber lengths are calculated using the EDFA model based on propagation and rate equations of a homogeneous, two-level medium.展开更多
Given is an analysis of broad-band Er-doped superfluorescent fiber source(EDSFS)filter using long period chirped fiber grating by transmission matrix method.For our EDSFS attenuated amplitude demand and the flattened ...Given is an analysis of broad-band Er-doped superfluorescent fiber source(EDSFS)filter using long period chirped fiber grating by transmission matrix method.For our EDSFS attenuated amplitude demand and the flattened wavelength range demand,proposed are the key factors of designing such filters of high performances.The simulation result demonstrates that such type filters have an enough attenuation to flatten the dramatic increase in output amplified spontaneous emission(ASE)in the wavelength range of 1529nm^1535nm by choosing conformable fiber filter parameters such as chirped degree,original period,induced index change,length of the fiber filter,and then broad-band EDSFS could be achieved.展开更多
976 nm+1976 nm dual-wavelength pumped Er-doped ZBLAN fiber lasers are generally accepted as the preferred solution for achieving 3.5μm lasing.However,the 2μm band excited state absorption from the upper lasing level...976 nm+1976 nm dual-wavelength pumped Er-doped ZBLAN fiber lasers are generally accepted as the preferred solution for achieving 3.5μm lasing.However,the 2μm band excited state absorption from the upper lasing level(^(4 )F_(9/2)→^(4)F_(7/2))depletes the Er ions population inversion,reducing the pump quantum efciency and limiting the power scaling.In this work,we demonstrate that the pump quantum efciency can be efectively improved by using a long-wavelength pump with lower excited state absorption rate.A 3.5μm Er-doped ZBLAN fber laser was built and its performances at diferent pump wavelengths were experimentally investigated in detail.A maximum output power at 3.46μm of~7.2 W with slope efciency(with respect to absorbed 1990 nm pump power)of 41.2%was obtained with an optimized pump wavelength of 1990 nm,and the pump quantum efciency was increased to 0.957 compared with the 0.819 for the conventional 1976 nm pumping scheme.Further power scaling was only limited by the available 1990 nm pump power.A numerical simulation was implemented to evaluate the cross section of excited state absorption via a theoretical ftting of experimental results.The potential of further power scaling was also discussed,based on the developed model.展开更多
Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of th...Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of the utilization of NbTe_(2)in ultrafast photonics have been reported.In this work,a NbTe_(2)-based saturable absorber(SA)was applied in an erbium-doped fiber as a mode-locked device,and a vector soliton based on NbTe_(2)was obtained for the first time.NbTe_(2)-PVA film SA was successfully prepared by the liquid-phase exfoliation and spin coating methods,with a modulation depth of up to 10.87%.The nonlinear absorption coefficient of NbTe_(2)-based SA film tested through the open-aperture Z-scan laser measurement is 0.62×10^(−11) m/W.A conventional soliton with a pulse duration of 858 fs was generated using NbTe_(2)-based SA,which was demonstrated to be a kind of polarization-locked vector soliton in further investigation.Our experimental results reveal the nonlinear optical properties of NbTe_(2)and broaden its applications in ultrafast photonic devices.展开更多
The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced at...The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation (RIA) self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation (RIBA) at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward (DPB) configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad (Si) gamma-ray irradiation.展开更多
s:Under The nonlinear optics condition the all-fiber optical bistability operation has been realized in an all-fiber resonator consisted of Er-dope fiber and optical fiber couplers.The experimental bistability thresho...s:Under The nonlinear optics condition the all-fiber optical bistability operation has been realized in an all-fiber resonator consisted of Er-dope fiber and optical fiber couplers.The experimental bistability threshold is consistent with the theory.展开更多
The linear and nonlinear charecteristics of verious optical riber loop resonators have been processed uniformly using transmission matrix method. It is pointed that in nonlinear operation condition each of those optic...The linear and nonlinear charecteristics of verious optical riber loop resonators have been processed uniformly using transmission matrix method. It is pointed that in nonlinear operation condition each of those optical fiber loop resonators may be used to make an all-optical fiber bistabillty device.The configuration,charecterictics and threshold of verious Er-doped fiber loop bistability devices have been calculated,analysised, and compared, and the design principle of those devices has been given.展开更多
Erbium fiber grating ring laser (EFRL) witn an integrated travelling wave and low polarization mode noise is reported. Through modulated experiment of a successful 2.488 Gb/s RZ data, it is shown that the EFRL is a pr...Erbium fiber grating ring laser (EFRL) witn an integrated travelling wave and low polarization mode noise is reported. Through modulated experiment of a successful 2.488 Gb/s RZ data, it is shown that the EFRL is a promising alternative to DFB lasers for high-speed transmission applications.展开更多
We demonstrate here an environmentally stable and extremely compactable Er-doped fiber laser system capable of delivering sub-100-fs temporal duration and tens of nanojoules at a repetition rate of 10 MHz.This laser s...We demonstrate here an environmentally stable and extremely compactable Er-doped fiber laser system capable of delivering sub-100-fs temporal duration and tens of nanojoules at a repetition rate of 10 MHz.This laser source employs a semiconductor saturable absorber mirror mode-locked soliton laser to generate seed pulses.A singlemode-fiber amplifier and a double-cladding-fiber amplifier(both with double-pass configuration)are bridged by a divider and used to manage the dispersion map and boost the soliton pulses.By using 64 replicas,pulses with as high as 60 n J energy within 95 fs duration are obtained at 10 MHz,corresponding to 600 kW peak power.展开更多
We report on a compact passive mode-locked Er:fiber ring laser operated at the fundamental repetition rate of 517 MHz, which we believe is the highest fundamental repetition rate ever reported in a ring cavity fiber l...We report on a compact passive mode-locked Er:fiber ring laser operated at the fundamental repetition rate of 517 MHz, which we believe is the highest fundamental repetition rate ever reported in a ring cavity fiber laser.The key technique is the employment of two innovative high-power wavelength domain multiplexer collimators with all gain fiber cavity suited for the high power(up to 2 W) pumping. The laser is featured with a direct chirpfree output pulse, which is 97 fs without extracavity compression at an average output power of 90 mW.展开更多
In this paper, we proposed a way to realize an Er-doped random fiber laser(RFL) with a disordered fiber Bragg grating(FBG) array, as well as to control the lasing mode of the RFL by heating specific locations of the d...In this paper, we proposed a way to realize an Er-doped random fiber laser(RFL) with a disordered fiber Bragg grating(FBG) array, as well as to control the lasing mode of the RFL by heating specific locations of the disordered FBG array. The disordered FBG array performs as both the gain medium and random distributed reflectors, which together with a tunable point reflector form the RFL. Coherent multi-mode random lasing is obtained with a threshold of between 7.5 and 10 mW and a power efficiency between 23% and 27% when the reflectivity of the point reflector changes from 4% to 50%. To control the lasing mode of random emission, a specific point of the disordered FBG array is heated so as to shift the wavelength of the FBG(s) at this point away from the other FBGs.Thus, different resonance cavities are formed, and the lasing mode can be controlled by changing the location of the heating point.展开更多
We propose a Q-switched Er-doped fiber laser (EDFL) with a threshold pumping power as low as 7.4 mW, and demonstrate using graphene polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). The SA ...We propose a Q-switched Er-doped fiber laser (EDFL) with a threshold pumping power as low as 7.4 mW, and demonstrate using graphene polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). The SA is fabricated from graphene flakes, which is synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. The flakes are mixed with PVA solution to produce a thin film, which is then sandwiched between two ferrules to form a SA and integrated in the EDFL ring cavity to generate a stable Q-switched pulse train. The pulse train operates at 1560 nm with a threshold pump power of 7.4 roW. At maximum 1480 nm pump power of 33.0 roW, the EDFL generates an optical pulse train with a repetition rate of 27.0 kHz and pulse width of 3.56/as. The maximum pulse energy of 39.4 nJ is obtained at a pump power of 14.9 roW. This laser can be used as a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics.展开更多
The Er-doped concentric-cores dispersion compensating fiber (EDDCF) has been demonstrated. The rare earth has been doped as a ring around the inner core. We have obtained 14-dB gain at 1550 nm (using 100-mW pump power...The Er-doped concentric-cores dispersion compensating fiber (EDDCF) has been demonstrated. The rare earth has been doped as a ring around the inner core. We have obtained 14-dB gain at 1550 nm (using 100-mW pump power and 980-nm wavelength) with dispersion of about -165 ps/(km·nm). It is useful for the optical fiber network where amplification as well as negative dispersion are necessary.展开更多
We demonstrated stable midinfrared(MIR) optical frequency comb at the 3.0 μm region with difference frequency generation pumped by a high power, Er-doped, ultrashort pulse fiber laser system. A soliton mode-locked161...We demonstrated stable midinfrared(MIR) optical frequency comb at the 3.0 μm region with difference frequency generation pumped by a high power, Er-doped, ultrashort pulse fiber laser system. A soliton mode-locked161 MHz high repetition rate fiber laser using a single wall carbon nanotube was fabricated. The output pulse was amplified in an Er-doped single mode fiber amplifier, and a 1.1–2.2 μm wideband supercontinuum(SC) with an average power of 205 m W was generated in highly nonlinear fiber. The spectrogram of the generated SC was examined both experimentally and numerically. The generated SC was focused into a nonlinear crystal, and stable generation of MIR comb around the 3 μm wavelength region was realized.展开更多
基金the National Key Research and Development Program of China(Grant No.2016YFF0200204)。
文摘Femtosecond optical frequency combs correlate the microwave and optical frequencies accurately and coherently.Therefore,any optical frequency in visible to near-infrared region can be directly traced to a microwave frequency.As a result,the length unit“meter”is directly related to the time unit“second”.This paper validates the capability of the national wavelength standards based on a home-made Er-doped fiber femtosecond optical frequency comb to measure the laser frequencies ranging from visible to near-infrared region.Optical frequency conversion in the femtosecond optical frequency comb is achieved by combining spectral broadening in a highly nonlinear fiber with a single-point frequencydoubling scheme.The signal-to-noise ratio of the beat notes between the femtosecond optical frequency comb and the lasers at 633,698,729,780,1064,and 1542 nm is better than 30 d B.The frequency instability of the above lasers is evaluated by using a hydrogen clock signal with a instability of better than 1×10^(-13)at 1-s averaging time.The measurement is further validated by measuring the absolute optical frequency of an iodine-stabilized 532-nm laser and an acetylenestabilized 1542-nm laser.The results are within the uncertainty range of the international recommended values.Our results demonstrate the accurate optical frequency measurement of lasers at different frequencies using the femtosecond optical frequency comb,which is not only important for the precise and accurate traceability and calibration of the laser frequencies,but also provides technical support for establishing the national wavelength standards based on the femtosecond optical frequency comb.
基金Supported by the National Natural Science Foundation of China under Grant No 11504320
文摘To obtain a stable amplified spontaneous emission(ASE) source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.
文摘Optical dispersive nonlinearities in Er-doped optical fiber are discussed and measured at the third window wavelength 1.55 μm for optical communications firstly. The experimental method, which is developed by us, is based on dynamic scanning for fixed-point-interference (DSFPI) of two fiber beams. The real part and complex value of the third-order susceptibility at the wavelength are also obtained from the measured Kerr coefficient and nonlinear-absorption coefficient reported elsewhere.
基金Project supported by the National Natural Science Foundation of China(Grant No.61605107)Young Eastern Scholar Program at Shanghai Institutions of Higher Learning,China(Grant No.QD2015027)+2 种基金the“Young 1000 Talent Plan”Program of Chinathe Open Program of the State Key Laboratory of Advanced Optical Communication Systems and Networks at Shanghai Jiaotong University,China(Grant No.2017GZKF17)RAEng/The Leverhulme Trust Senior Research Fellowships(Grant No.LTSRF1617/13/57).
文摘We demonstrate a passively harmonic mode-locked(PHML) fiber laser operating at the L-band using carbon nanotubes polyvinyl alcohol(CNTs-PVA) film. Under suitable pump power and an appropriate setting of the polarization controller(PC), the 54^(th) harmonic pulses at the L-band are generated with the side mode suppression ratio(SMSR) better than 44 dB and a repetition frequency of 503.37 MHz. Further increasing the pump power leads to a higher frequency of 550 MHz with compromised stability of 38.5 dB SMSR. To the best of our knowledge, this is the first demonstration on the generation of L-band PHML pulses from an Er-doped fiber laser based on CNTs.
基金supported by National Natural Science Foundation of China and Scientific Forefront and Interdisciplinary Innovation Project, Jilin University under Grants No. 60372061,200903296
文摘In this paper, we adopt cloud computing in a specific scientific computing field for its virtualization, distribution and dynamic extendibility as follows: We obtain high-energy parabolic self-similar pulses by numerical simulation using our non-distributed passively mode-locked Er-doped fiber laser model. For researching characteristics of these wave-breaking-free self-similar pulses, chirp of them must be extracted. We propose several time-frequency analysis methods adopted in chirp extraction of ultra-short optical pulses for the first time and discuss the advantages and disadvantages of them in this particular application.
基金Supported by the National Natural Science Foundation of China under Grant No 61705183the Central University Special Fund Basic Research and Operating Expenses under Grant No GK201702005+1 种基金the Natural Science Foundation of Shaanxi Province under Grant No 2017JM6091the Fundamental Research Funds for the Central Universities under Grant No 2017TS011
文摘Using the reduced graphene oxide(rGO) as a saturable absorber(SA) in an Er-doped fiber(EDF) laser cavity,we obtain the Q-switching operation. The rGO SA is prepared by depositing the GO on fluorine mica(FM) using the thermal reduction method. The modulation depth of rGO/FM is measured to be 3.2%. By incorporating the rGO/FM film into the EDF laser cavity, we obtain stable Q-switched pulses. The shortest pulse duration is3.53 μs, and the maximum single pulse energy is 48.19 nJ. The long-term stability of working is well exhibited.The experimental results show that the rGO possesses potential photonics applications.
基金Foundation of Beijing Jiaotong University(2005RC034)
文摘Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have different coupling constants and propagation losses. We calculate the effective pump power absorption ratio along the fiber with different coupling constants from the first cladding to the doped core and with different propagation losses for the power in the inner cladding. Then the gains of the double clad Er-doped fiber amplifiers versus fiber lengths are calculated using the EDFA model based on propagation and rate equations of a homogeneous, two-level medium.
文摘Given is an analysis of broad-band Er-doped superfluorescent fiber source(EDSFS)filter using long period chirped fiber grating by transmission matrix method.For our EDSFS attenuated amplitude demand and the flattened wavelength range demand,proposed are the key factors of designing such filters of high performances.The simulation result demonstrates that such type filters have an enough attenuation to flatten the dramatic increase in output amplified spontaneous emission(ASE)in the wavelength range of 1529nm^1535nm by choosing conformable fiber filter parameters such as chirped degree,original period,induced index change,length of the fiber filter,and then broad-band EDSFS could be achieved.
基金supported by the National Natural Science Foundation of China(Grant Nos.62105240,62075159,61975146,and 62275190)Shandong Province Key R&D Program(Nos.2020CXGC010104 and 2021CXGC010202)Seed Foundation of Tianjin University(No.2023XPD-0020).
文摘976 nm+1976 nm dual-wavelength pumped Er-doped ZBLAN fiber lasers are generally accepted as the preferred solution for achieving 3.5μm lasing.However,the 2μm band excited state absorption from the upper lasing level(^(4 )F_(9/2)→^(4)F_(7/2))depletes the Er ions population inversion,reducing the pump quantum efciency and limiting the power scaling.In this work,we demonstrate that the pump quantum efciency can be efectively improved by using a long-wavelength pump with lower excited state absorption rate.A 3.5μm Er-doped ZBLAN fber laser was built and its performances at diferent pump wavelengths were experimentally investigated in detail.A maximum output power at 3.46μm of~7.2 W with slope efciency(with respect to absorbed 1990 nm pump power)of 41.2%was obtained with an optimized pump wavelength of 1990 nm,and the pump quantum efciency was increased to 0.957 compared with the 0.819 for the conventional 1976 nm pumping scheme.Further power scaling was only limited by the available 1990 nm pump power.A numerical simulation was implemented to evaluate the cross section of excited state absorption via a theoretical ftting of experimental results.The potential of further power scaling was also discussed,based on the developed model.
基金supported by the National Natural Science Foundation of China(Grant Nos.61971271,11904213,and 11747149)the Jinan City-School Integration Development Strategy Project(Grant No.JNSX2021023)+4 种基金the Shandong Province Major Technological Innovation Project(Grant No.2022CXGC010502)the Shandong Province Natural Science Foundation(Grant No.ZR2018QF006)the Key Project of Department of Education of Guangdong Province(Grant No.2018KCXTD026)the Deanship of Scientific Research(DSR)at King Abdulaziz University,Jeddah(Grant No.KEP-MSc-70-130-42)the“Opening Foundation of Shandong Provincial Key Laboratory of Laser Technology and Application”.
文摘Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of the utilization of NbTe_(2)in ultrafast photonics have been reported.In this work,a NbTe_(2)-based saturable absorber(SA)was applied in an erbium-doped fiber as a mode-locked device,and a vector soliton based on NbTe_(2)was obtained for the first time.NbTe_(2)-PVA film SA was successfully prepared by the liquid-phase exfoliation and spin coating methods,with a modulation depth of up to 10.87%.The nonlinear absorption coefficient of NbTe_(2)-based SA film tested through the open-aperture Z-scan laser measurement is 0.62×10^(−11) m/W.A conventional soliton with a pulse duration of 858 fs was generated using NbTe_(2)-based SA,which was demonstrated to be a kind of polarization-locked vector soliton in further investigation.Our experimental results reveal the nonlinear optical properties of NbTe_(2)and broaden its applications in ultrafast photonic devices.
基金supported by the Special Fund for Development of National Major Scientific Instruments of China(Grant No.2013YQ04081504)the Program for Innovative Research Team in University,China(Grant No.IRT 1203)
文摘The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation (RIA) self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation (RIBA) at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward (DPB) configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad (Si) gamma-ray irradiation.
文摘s:Under The nonlinear optics condition the all-fiber optical bistability operation has been realized in an all-fiber resonator consisted of Er-dope fiber and optical fiber couplers.The experimental bistability threshold is consistent with the theory.
文摘The linear and nonlinear charecteristics of verious optical riber loop resonators have been processed uniformly using transmission matrix method. It is pointed that in nonlinear operation condition each of those optical fiber loop resonators may be used to make an all-optical fiber bistabillty device.The configuration,charecterictics and threshold of verious Er-doped fiber loop bistability devices have been calculated,analysised, and compared, and the design principle of those devices has been given.
文摘Erbium fiber grating ring laser (EFRL) witn an integrated travelling wave and low polarization mode noise is reported. Through modulated experiment of a successful 2.488 Gb/s RZ data, it is shown that the EFRL is a promising alternative to DFB lasers for high-speed transmission applications.
基金supported by the National Key R&D Program of China(No.2018YFB0407100)
文摘We demonstrate here an environmentally stable and extremely compactable Er-doped fiber laser system capable of delivering sub-100-fs temporal duration and tens of nanojoules at a repetition rate of 10 MHz.This laser source employs a semiconductor saturable absorber mirror mode-locked soliton laser to generate seed pulses.A singlemode-fiber amplifier and a double-cladding-fiber amplifier(both with double-pass configuration)are bridged by a divider and used to manage the dispersion map and boost the soliton pulses.By using 64 replicas,pulses with as high as 60 n J energy within 95 fs duration are obtained at 10 MHz,corresponding to 600 kW peak power.
基金supported by the Major National Basic Research Program of China (2013CB922401)the National Natural Science Foundation of China (60927010, 10974006, and 11027404)
文摘We report on a compact passive mode-locked Er:fiber ring laser operated at the fundamental repetition rate of 517 MHz, which we believe is the highest fundamental repetition rate ever reported in a ring cavity fiber laser.The key technique is the employment of two innovative high-power wavelength domain multiplexer collimators with all gain fiber cavity suited for the high power(up to 2 W) pumping. The laser is featured with a direct chirpfree output pulse, which is 97 fs without extracavity compression at an average output power of 90 mW.
基金supported in part by the National Natural Science Foundation of China under Grants 61575040 and 61106045the PCSIRT under Grant IRT1218+1 种基金the 111 Project under Grant B14039the open research fund of Jiangsu Key Laboratory for Advanced Optical Manufacturing Technologies under Grant KJS1402
文摘In this paper, we proposed a way to realize an Er-doped random fiber laser(RFL) with a disordered fiber Bragg grating(FBG) array, as well as to control the lasing mode of the RFL by heating specific locations of the disordered FBG array. The disordered FBG array performs as both the gain medium and random distributed reflectors, which together with a tunable point reflector form the RFL. Coherent multi-mode random lasing is obtained with a threshold of between 7.5 and 10 mW and a power efficiency between 23% and 27% when the reflectivity of the point reflector changes from 4% to 50%. To control the lasing mode of random emission, a specific point of the disordered FBG array is heated so as to shift the wavelength of the FBG(s) at this point away from the other FBGs.Thus, different resonance cavities are formed, and the lasing mode can be controlled by changing the location of the heating point.
基金financially supported by the Ministry of Education and the University of Malaya under Grant Nos.ER012-2013A and RP008D-13AET
文摘We propose a Q-switched Er-doped fiber laser (EDFL) with a threshold pumping power as low as 7.4 mW, and demonstrate using graphene polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). The SA is fabricated from graphene flakes, which is synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. The flakes are mixed with PVA solution to produce a thin film, which is then sandwiched between two ferrules to form a SA and integrated in the EDFL ring cavity to generate a stable Q-switched pulse train. The pulse train operates at 1560 nm with a threshold pump power of 7.4 roW. At maximum 1480 nm pump power of 33.0 roW, the EDFL generates an optical pulse train with a repetition rate of 27.0 kHz and pulse width of 3.56/as. The maximum pulse energy of 39.4 nJ is obtained at a pump power of 14.9 roW. This laser can be used as a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics.
文摘The Er-doped concentric-cores dispersion compensating fiber (EDDCF) has been demonstrated. The rare earth has been doped as a ring around the inner core. We have obtained 14-dB gain at 1550 nm (using 100-mW pump power and 980-nm wavelength) with dispersion of about -165 ps/(km·nm). It is useful for the optical fiber network where amplification as well as negative dispersion are necessary.
基金Japan Science and Technology Agency(JST)Japan Agency for Medical Research and Development(AMED)
文摘We demonstrated stable midinfrared(MIR) optical frequency comb at the 3.0 μm region with difference frequency generation pumped by a high power, Er-doped, ultrashort pulse fiber laser system. A soliton mode-locked161 MHz high repetition rate fiber laser using a single wall carbon nanotube was fabricated. The output pulse was amplified in an Er-doped single mode fiber amplifier, and a 1.1–2.2 μm wideband supercontinuum(SC) with an average power of 205 m W was generated in highly nonlinear fiber. The spectrogram of the generated SC was examined both experimentally and numerically. The generated SC was focused into a nonlinear crystal, and stable generation of MIR comb around the 3 μm wavelength region was realized.