A novel timing jitter reduction system over a round trip 20-km urban fiber link is reported. The phase difference of the ninth harmonic of a high-repetition-rate mode-locked laser between the local and the returned si...A novel timing jitter reduction system over a round trip 20-km urban fiber link is reported. The phase difference of the ninth harmonic of a high-repetition-rate mode-locked laser between the local and the returned signals is obtained. Based on the phase difference, the system uses an optical delay line （ODL） to compensate the optical fiber link. The root-mean-square （RMS） timing jitter is reduced from 50 to 8.9 ps in 80 min.展开更多
Based on the coupled Ginzburg-Landu equation, we numerically investigate the pulse dynamics in a dispersion-managed normal dispersion Tin-doped mode-locked fiber laser. The influences of the rood-ulation depth and sat...Based on the coupled Ginzburg-Landu equation, we numerically investigate the pulse dynamics in a dispersion-managed normal dispersion Tin-doped mode-locked fiber laser. The influences of the rood-ulation depth and saturation power of saturable absorber on the pulse dynamics are presented. The simulation results show that these parameters are crucial to achieve high pulse energy and high pulse peak power pulsed laser near 2-μm wavelength.展开更多
This Letter demonstrates the application of dual-output modulation in a photonic analog-to-digital converter （PADC） with a high sampling rate and resolution. The PADC is time-wavelength interleaved and based on an a...This Letter demonstrates the application of dual-output modulation in a photonic analog-to-digital converter （PADC） with a high sampling rate and resolution. The PADC is time-wavelength interleaved and based on an actively mode-locked laser. According to theoretical analysis, the dual-output PADC system shows a better linearity for achieving a higher dynamic range. In the experiment, third-order distortion is significantly sup- pressed by -40 dB when the dual-output modulator is used and the effective number of bits of the PADC has reached 9.0 bits below 0.2 GHz and 6.4 bits at 6.1 GHz in our PADC with a sampling rate of 20 GS/s.展开更多
We report on the generation of Q-switched and Q-switched mode-locked （QML） pulses in an erbium-doped fiber ring laser by using a polyvinyl alcohol （PVA） -based gold nanorod （GNR） saturable absorber （SA）. The P...We report on the generation of Q-switched and Q-switched mode-locked （QML） pulses in an erbium-doped fiber ring laser by using a polyvinyl alcohol （PVA） -based gold nanorod （GNR） saturable absorber （SA）. The PVA- based GNR SA has a modulation depth of -4.8% and a non-saturable loss of -26.9% at 1.5 μm. A Q-switched pulse train with a repetition rate varying from 18.70 to 39.85 kHz and a QML pulse train with an envelope repetition rate tuning from 20.31 to 31.50 kHz are obtained. Moreover, the lasing wavelengths of the Q-switched pulses can be flexibly tuned by introducing a narrow bandwidth, tunable filter into the laser cavity. The results demonstrate that the GNRs exhibit good optical performance and can find a wide range of applications in the field of laser technology.展开更多
We design a laser diode （LD） end-pumped passively mode-locked solid-state laser with a semiconductor saturable absorber mirror. Mode-matching efficiency in the active medium including the thermal effect is analyzed,...We design a laser diode （LD） end-pumped passively mode-locked solid-state laser with a semiconductor saturable absorber mirror. Mode-matching efficiency in the active medium including the thermal effect is analyzed, and the optimum mode-matching coefficient is obtained by optimizing the pump mode. In the experiment, a total power of 4.2 W stable pulse sequences without multipulse at 1064 nm is obtained with a pulse repetition rate of 86 MHz and a pulse width of 13 ps, corresponding to a high optical to optical efficiency of 44%.展开更多
We propose and experimentally demonstrate a scheme of high-Q microwave photonic filter （MPF） using the techniques of self-phase modulation （SPM） spectrum broadening and third-order dispersion （TOD） compensation....We propose and experimentally demonstrate a scheme of high-Q microwave photonic filter （MPF） using the techniques of self-phase modulation （SPM） spectrum broadening and third-order dispersion （TOD） compensation. The optical pulses from a mode-locking laser are spectrally broadened by the SPM in the highly nonlinear fiber. A wideband optical frequency comb with 365 spectral lines within 10-dB power variation from the highest spectral power is obtained. By applying a cubic phase modulation via a waveshaper, the effect of TOD which broadens the MPF passband is eliminated. The final implemented MPF has a Q-value as high as 296 and a tuning range of 700 MHz.展开更多
We investigate the effects of a piece of zero-dispersion fiber （ZDF） on the pulse dynamics of a passively mode-locked fiber laser operating in the stretched-pulse regime. Numerical simulation suggests that the prope...We investigate the effects of a piece of zero-dispersion fiber （ZDF） on the pulse dynamics of a passively mode-locked fiber laser operating in the stretched-pulse regime. Numerical simulation suggests that the proper location and length of ZDF facilitate spectrum broadening and pulse shortening in fiber lasers while maintaining constant net cavity dispersion. A nonlinear polarization evolution mode-locked Er-doped fiber laser with a dispersion map is built based on the simulation. Larger optical spectrum broadening is obtained by inserting a longer ZDF after the active fiber during single-pulse operation, which well agrees with the simulation.展开更多
An optimized dual fiber Bragg grating （FBG） is proposed for 980-nm semiconductor lasers without thermoelectric coolers to restrict temperature-induced wavelength shift.The mathematical model of the temperature-induc...An optimized dual fiber Bragg grating （FBG） is proposed for 980-nm semiconductor lasers without thermoelectric coolers to restrict temperature-induced wavelength shift.The mathematical model of the temperature-induced wavelength shift of the laser with the dual FBG is built using the external cavity feedback rate equations.The external cavity parameters are optimized for achieving the stability mode-locking laser output.The spectral characteristics of the dual FBG stabilized laser are measured to range from 0 to 70 °C.The side mode suppression ratio （SMSR） is more than 45 dB,while the full-width at half-maximum （FWHM） is less than 1 nm.The peak wavelength shift is less than 0.1 nm.The dual FBG wavelength shift proportional coefficient is between 0.1086 and 0.4342.展开更多
We experimentally demonstrate a femtosecond optical parametric oscillator （OPO） synchronously pmnped by a home-made solid-state mode-locking Yb：YCOB laser, which is capable of laser pulse as short as 102 fs and ave...We experimentally demonstrate a femtosecond optical parametric oscillator （OPO） synchronously pmnped by a home-made solid-state mode-locking Yb：YCOB laser, which is capable of laser pulse as short as 102 fs and average power of 620 mW at the central wavelength of 1052 nm. By using a periodically poled lithium niobate with tuning of the grating periods from 28.5 to 31.5μm as the nonlinear gain crystal, tunable femtosecond pulses from 1444 to 1683 nm are realized by conveniently adjusting the OPO cavity length with 76.8 MHz repetition rate. The maximum average output power is 152 mW at 1568 nm, corresponding to an idler power of 75 mW at 3197 nm as well as 36.6% total extraction efficiency.展开更多
We report, for the first time to our knowledge, a diode-end-pumped passively mode-locked（ML） Nd-doped gadolinium gallium garnet laser based on a chemically reduced graphene oxide（RGO） saturable absorber mirror. Th...We report, for the first time to our knowledge, a diode-end-pumped passively mode-locked（ML） Nd-doped gadolinium gallium garnet laser based on a chemically reduced graphene oxide（RGO） saturable absorber mirror. The ML laser gives a pulse duration of 15.1 ps under the maximum average output power of 1.44 W, corresponding to a slope efficiency of 21.1%. The single-pulse energy and peak power are 21.6 n J and 1.43 k W, respectively. The results indicate that our RGO saturable absorber has promising prospects for applications in high-power and high-efficiency ultrafast lasers.展开更多
The output characteristics of the Er-doped mode-locked fiber laser using a single-walled carbon nanotube saturable absorber are investigated theoretically with a nonlinear Schrtidinger equation and a saturable absorpt...The output characteristics of the Er-doped mode-locked fiber laser using a single-walled carbon nanotube saturable absorber are investigated theoretically with a nonlinear Schrtidinger equation and a saturable absorption equation using realistic parameters. Stable self-starting mode-locking pulses are achieved under net normal, net zero, and net anomalous cavity group velocity dispersion （GVD） respectively. A spectrum with a flat top is obtained from the net normal cavity GVD laser while a spectrum with Kelly side-bands is obtained from the net anomalous cavity GVD laser. The characteristics of the pulse duration changing with cavity GVD and modulation depth of the single-walled carbon nanotubes are discussed. The characteristics of the mode-locking pulses from net normal, net zero, and net anomalous cavity GVD mode-locked fiber lasers are compared. These systematical results are useful for designing mode-locked fiber lasers with saturable absorbers made by different kinds of carbon nano-materials.展开更多
文摘A novel timing jitter reduction system over a round trip 20-km urban fiber link is reported. The phase difference of the ninth harmonic of a high-repetition-rate mode-locked laser between the local and the returned signals is obtained. Based on the phase difference, the system uses an optical delay line （ODL） to compensate the optical fiber link. The root-mean-square （RMS） timing jitter is reduced from 50 to 8.9 ps in 80 min.
基金supported by the National Natural Science Foundation of China(No.61205125)the Fundamental Research Funds for the Central Universities
文摘Based on the coupled Ginzburg-Landu equation, we numerically investigate the pulse dynamics in a dispersion-managed normal dispersion Tin-doped mode-locked fiber laser. The influences of the rood-ulation depth and saturation power of saturable absorber on the pulse dynamics are presented. The simulation results show that these parameters are crucial to achieve high pulse energy and high pulse peak power pulsed laser near 2-μm wavelength.
基金supported by the National Natural Science Foundation of China(Nos.61535006 and 61571292)the Specialized Research Fund within the Doctoral Program through the Ministry of Education(No.20130073130005)the State Key Laboratory Project of Shanghai Jiao Tong University(No.2014ZZ03016)
文摘This Letter demonstrates the application of dual-output modulation in a photonic analog-to-digital converter （PADC） with a high sampling rate and resolution. The PADC is time-wavelength interleaved and based on an actively mode-locked laser. According to theoretical analysis, the dual-output PADC system shows a better linearity for achieving a higher dynamic range. In the experiment, third-order distortion is significantly sup- pressed by -40 dB when the dual-output modulator is used and the effective number of bits of the PADC has reached 9.0 bits below 0.2 GHz and 6.4 bits at 6.1 GHz in our PADC with a sampling rate of 20 GS/s.
基金supported by the National Natural Science Foundation of China(Grant Nos.61378036,61307058,11304101,11074078,and 11474108)the Ph D Start-Up Fund of the Natural Science Foundation of Guangdong Province,China(Grant No.S2013040016320)+2 种基金the Scientific Research Foundation of the Graduate School of South China Normal University,China(Grant No.2014bsxm06)the Zhujiang New-Star Plan of Science and Technology in Guangzhou City(Grant No.2014J2200008)the Open Fund of the Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques(South China University of Technology)
文摘We report on the generation of Q-switched and Q-switched mode-locked （QML） pulses in an erbium-doped fiber ring laser by using a polyvinyl alcohol （PVA） -based gold nanorod （GNR） saturable absorber （SA）. The PVA- based GNR SA has a modulation depth of -4.8% and a non-saturable loss of -26.9% at 1.5 μm. A Q-switched pulse train with a repetition rate varying from 18.70 to 39.85 kHz and a QML pulse train with an envelope repetition rate tuning from 20.31 to 31.50 kHz are obtained. Moreover, the lasing wavelengths of the Q-switched pulses can be flexibly tuned by introducing a narrow bandwidth, tunable filter into the laser cavity. The results demonstrate that the GNRs exhibit good optical performance and can find a wide range of applications in the field of laser technology.
基金supported by the State KeyLaboratory of Tribology, Tsinghua University underGrant No. SKLT08A05.
文摘We design a laser diode （LD） end-pumped passively mode-locked solid-state laser with a semiconductor saturable absorber mirror. Mode-matching efficiency in the active medium including the thermal effect is analyzed, and the optimum mode-matching coefficient is obtained by optimizing the pump mode. In the experiment, a total power of 4.2 W stable pulse sequences without multipulse at 1064 nm is obtained with a pulse repetition rate of 86 MHz and a pulse width of 13 ps, corresponding to a high optical to optical efficiency of 44%.
基金the National Key Basic Research Program of China(Nos.2012CB315603 and 2012CB315604)the National Natural Science Foundation of China(Nos.61025004,61032005,and61321004).
文摘We propose and experimentally demonstrate a scheme of high-Q microwave photonic filter （MPF） using the techniques of self-phase modulation （SPM） spectrum broadening and third-order dispersion （TOD） compensation. The optical pulses from a mode-locking laser are spectrally broadened by the SPM in the highly nonlinear fiber. A wideband optical frequency comb with 365 spectral lines within 10-dB power variation from the highest spectral power is obtained. By applying a cubic phase modulation via a waveshaper, the effect of TOD which broadens the MPF passband is eliminated. The final implemented MPF has a Q-value as high as 296 and a tuning range of 700 MHz.
基金supported by the National Key Basic Research Special Foundation of China(Nos.2011CB808101 and 2010CB327604)the National Natural Science Foundation of China(Nos.60838004,60678012,60978022,61078028,61205131,and11274239)+2 种基金the New Century Excellent Talents(No.NCET-07-0597)the Doctoral Program Foundation of Institution of Higher Education of China(No.20090032110050)the National"111"Project of China(No.B07014)
文摘We investigate the effects of a piece of zero-dispersion fiber （ZDF） on the pulse dynamics of a passively mode-locked fiber laser operating in the stretched-pulse regime. Numerical simulation suggests that the proper location and length of ZDF facilitate spectrum broadening and pulse shortening in fiber lasers while maintaining constant net cavity dispersion. A nonlinear polarization evolution mode-locked Er-doped fiber laser with a dispersion map is built based on the simulation. Larger optical spectrum broadening is obtained by inserting a longer ZDF after the active fiber during single-pulse operation, which well agrees with the simulation.
基金supported by the National High-Tech Research and Development ("863") Program of China (No.2006AA03Z348)the Key Program of Science and Technology Research of Shanghai Education Commission (No.10ZZ94)+1 种基金the Shanghai Leading Academic Discipline Project (No.S30502)the Shanghai Talents Developing Foundation (No.014)
文摘An optimized dual fiber Bragg grating （FBG） is proposed for 980-nm semiconductor lasers without thermoelectric coolers to restrict temperature-induced wavelength shift.The mathematical model of the temperature-induced wavelength shift of the laser with the dual FBG is built using the external cavity feedback rate equations.The external cavity parameters are optimized for achieving the stability mode-locking laser output.The spectral characteristics of the dual FBG stabilized laser are measured to range from 0 to 70 °C.The side mode suppression ratio （SMSR） is more than 45 dB,while the full-width at half-maximum （FWHM） is less than 1 nm.The peak wavelength shift is less than 0.1 nm.The dual FBG wavelength shift proportional coefficient is between 0.1086 and 0.4342.
基金partly supported by the National Natural Science Foundation of China(No.61205130)the National Key Basic Research Program of China(No.2013CB922402)the National Key Scientific Instruments Development Program of China(No.2012YQ120047)
文摘We experimentally demonstrate a femtosecond optical parametric oscillator （OPO） synchronously pmnped by a home-made solid-state mode-locking Yb：YCOB laser, which is capable of laser pulse as short as 102 fs and average power of 620 mW at the central wavelength of 1052 nm. By using a periodically poled lithium niobate with tuning of the grating periods from 28.5 to 31.5μm as the nonlinear gain crystal, tunable femtosecond pulses from 1444 to 1683 nm are realized by conveniently adjusting the OPO cavity length with 76.8 MHz repetition rate. The maximum average output power is 152 mW at 1568 nm, corresponding to an idler power of 75 mW at 3197 nm as well as 36.6% total extraction efficiency.
基金supported by the National Natural Science Foundation of China(Nos.61308042 and 51321091)the Project of Shandong Province Higher Educational Science and Technology Program(No.J11L13)the Key Laboratory of Functional Crystal Materials and Device(Shandong University),Ministry of Education(No.KF1207)
文摘We report, for the first time to our knowledge, a diode-end-pumped passively mode-locked（ML） Nd-doped gadolinium gallium garnet laser based on a chemically reduced graphene oxide（RGO） saturable absorber mirror. The ML laser gives a pulse duration of 15.1 ps under the maximum average output power of 1.44 W, corresponding to a slope efficiency of 21.1%. The single-pulse energy and peak power are 21.6 n J and 1.43 k W, respectively. The results indicate that our RGO saturable absorber has promising prospects for applications in high-power and high-efficiency ultrafast lasers.
基金supported by the National Key Basic Research Progrm of China(Grant No.2013CB922404)the National Natural Science Foundation of China(Grant No.61177047)the Key Project of the National Natural Science Foundation of China(Grant No.61235010)
文摘The output characteristics of the Er-doped mode-locked fiber laser using a single-walled carbon nanotube saturable absorber are investigated theoretically with a nonlinear Schrtidinger equation and a saturable absorption equation using realistic parameters. Stable self-starting mode-locking pulses are achieved under net normal, net zero, and net anomalous cavity group velocity dispersion （GVD） respectively. A spectrum with a flat top is obtained from the net normal cavity GVD laser while a spectrum with Kelly side-bands is obtained from the net anomalous cavity GVD laser. The characteristics of the pulse duration changing with cavity GVD and modulation depth of the single-walled carbon nanotubes are discussed. The characteristics of the mode-locking pulses from net normal, net zero, and net anomalous cavity GVD mode-locked fiber lasers are compared. These systematical results are useful for designing mode-locked fiber lasers with saturable absorbers made by different kinds of carbon nano-materials.
