Junsong Peng
Shanghai Jiao Tong University
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Publication
Featured researches published by Junsong Peng.
Optics Express | 2009
Kai Qian; Li Zhan; Honggen Li; Xiao Hu; Junsong Peng; Liang Zhang; Yuxing Xia
We proposed and experimentally demonstrated an extremely simple and feasible slow-light technique to achieve tunable optical delay by using the Er/Yb codoped fiber Bragg grating (FBG). The signal light experiences strong dispersion when it is launched into the reflection edge of FBG, and the group delay value is determined by the signal wavelength and the pump power. In the experiment, a controllable delay of 0.9 ns can be obtained through changing the 980 nm pump power. The group velocity can be slowed down to 5.6x10(7) m/s, which is 19% of the speed of light in free space. It provides a very simple approach to control the light group delay, which is likely to have important implications for practical applications.
Optics Letters | 2011
Kai Qian; Li Zhan; Lumin Zhang; Z. Q. Zhu; Junsong Peng; Zhaochang Gu; Xiao Hu; Shouyu Luo; Yuxing Xia
We propose and experimentally demonstrate the propagation of slow/fast light in an erbium-doped fiber (EDF) using mutually modulated cross-gain modulation. The group velocity of the light signal can be manipulated by the effect of gain cross-saturation modulation by a saturating light at an arbitrary wavelength in the gain bandwidth of the EDF. The ultraslow propagation with a small group velocity of 5.6 × 10⁻³c (c is the light speed in free space) and superluminal propagation with a negative group velocity of -1.1 × 10⁻³c has been observed under different modulation phases.
Journal of Lightwave Technology | 2013
Junsong Peng; Li Zhan; Shouyu Luo; Qishun Shen
Tunable harmonic mode-locking of (HML) one kind of dissipative solitons (DSs) has been experimentally demonstrated in an Er-doped fiber (EDF) laser for the first time. The laser is mode-locked by nonlinear polarization rotation. The repetition rate can be tuned from the 2nd to 10th-order HML. A high repetition rate of 232 MHz (10th- order HML) has been observed in this laser, and the pulse duration after compression is 153-fs with single-pulse energy of 0.5 nJ. The spectral width of the pulses decreases as the harmonic order increases in the experiment, which is demonstrated for the first time, consistent with the numerical study. A rule based on monitoring the pulse spectral width to find desired-order HML is also proposed.
IEEE Photonics Technology Letters | 2013
Junsong Peng; Li Zhan; Shouyu Luo; Qishun S. Shen
Though normal-dispersion mode-locked fiber lasers generally work on a single-pulse regime due to the large chirp of the pulses, we observe bound states of one kind of dissipative solitons in the laser. The separation between the bounded pulses in such soliton molecules increases with the pump power, and also varies with the settings of polarization controllers, which is consistent with other kinds of bounded pulses such as solitons. Our study indicates that the bound state of pulses is an intrinsic feature of mode-locked lasers and is independent of pulse profiles, stimulated by overdriving of mode-locking mechanisms.
Physical Review A | 2012
Junsong Peng; Li Zhan; Zhaochang Gu; Kai Qian; Shouyu Luo; Qishun Shen
Transitions between different kinds of soliton solutions of Ginzburg-Landau equation (GLE) have been studied experimentally in a mode-locked fiber laser. It is demonstrated that the different kinds of solitons corresponding to different solutions of GLE can be generated in a single mode-locked laser. Dispersion-managed solitons (DM), all-normal-dispersion solitons (ANDi) and similaritons can be emitted respectively depending on the parameter of the intensity of the light field and the birefringence effect. The three nonlinear waves show different features especially the spectrum shapes and dynamics accompanying with pump power scaling. Such phenomenon reveals the properties of GLE, which is not only scientifically interesting but also valuable to practical applications of mode-locked fiber lasers.
IEEE Photonics Technology Letters | 2012
Junsong Peng; Li Zhan; Zhaochang Gu; Kai Qian; Xiao Hu; Shouyu Luo; Qishun Shen
We have demonstrated the direct generation of 4.6-nJ 78.9-fs ultrashort pulses with 58 kW peak power in an all-fiber net-normal-dispersion oscillator. Such high peak power is a record in an all-fiber oscillator and is comparable to chirped-pulse amplification systems. The corresponding spectrum has steep spectral edges, which is the typical shape of dissipative solitons (DS). Also, we find that the spectral width is tunable from 40 to 58 nm by adjusting polarization controllers, and the pulse duration can be tuned from 1.7 ps to 120 fs through increasing the pump power, which is attractive to applications. Besides, we demonstrate experimentally the relationship between spectral width and the pump power of DS laser for the first time.
Laser Physics | 2013
Mengmeng Tao; Junjie Wu; Junsong Peng; Yong Wu; Pengling Yang; Xisheng Ye
Mode-locking operation of an Er-doped fiber laser with a Tm?Ho co-doped fiber saturable absorber is demonstrated for the first time. Q-switching, Q-switched mode-locking and CW mode-locking operation modes are observed sequentially with increase of the pump power. In the mode-locking operation mode, a repetition rate at the fundamental cavity frequency of 9.05?MHz is obtained with a pulse duration of 46.3 ns. By rotating the polarization controller, a repetition rate up to 887?MHz is achieved, and the pulse duration is shortened to 0.548?ns.
Optics Express | 2016
Junsong Peng; Nikita Tarasov; Srikanth Sugavanam; Dmitry Churkin
We report for the first time, rogue waves generation in a mode-locked fiber laser that worked in multiple-soliton state in which hundreds of solitons occupied the whole laser cavity. Using real-time spatio-temporal intensity dynamics measurements, it is unveiled that nonlinear soliton collision accounts for the formation of rogue waves in this laser state. The nature of interactions between solitons are also discussed. Our observation may suggest similar formation mechanisms of rogue waves in other systems.
Journal of Lightwave Technology | 2012
Junsong Peng; Li Zhan; Zhaochang Gu; Jinmei Liu; Shouyu Luo; Xuehao Shen; Qishun Shen
Modulation instability (MI) in passively mode-locked dissipative solitons lasers has been studied. The factors that affect MI, including the intensity of the nonlinear wave and the linear phase delay of the cavity, have been experimentally studied. Its found that MI induces sidebands in the spectrum of dissipative solitons. The sidebands can cause the pedestal on the pulse in time domain and thus limit the pulse duration. Additionally, a simple method to eliminate the sidebands is proposed and nearly pedestal free pulses are generated correspondingly. Finally, based on MI, a method to measure the cavity net dispersion is proposed and applied to two dissipative soliton lasers with different net dispersion. Its shown that the positions of the adjacent spectral sidebands can determine the intracavity net dispersion, and the measurement error is limited by the accuracy of the optical spectrum analyzer. This indicates it is a simple and precise method to measure the intracavity net dispersion.
IEEE Photonics Technology Letters | 2013
Jinmei Liu; Li Zhan; Pingping Xiao; Gaomeng Wang; Liang Zhang; Xuesong Liu; Junsong Peng; Qishun Shen
We propose and demonstrate an all-fiber scheme to generate step-tunable microwave signals by heterodyning two Stokes lasing lights from a multiwavelength Brillouin fiber laser. Ten orders of Stokes lasing have been observed with rigid ~11-GHz frequency spacing, and each order of Stokes works on single-longitudinal-mode operation. The generated microwave frequency is equivalent to the difference between two arbitrary orders Stokes from the laser. A ~22-GHz microwave signal is obtained and the signal linewidth is less than 2 kHz. As a potential application, a step-tunable microwave source ranging from ~11 to ~77 GHz is proposed and partially demonstrated.