Transient behaviors of pure soliton pulsations and soliton explosion in an L-band normal-dispersion mode-locked fiber laser

As one of the most striking localized structures in dissipative systems, pulsating soliton has been widely studied in theory, but rarely observed in experiments. Here, three typical types of soliton pulsations are experimentally demonstrated in an L-band normal-dispersion mode-locked fiber laser via the dispersive Fourier transform (DFT) technique. According to the distinctive features, they are classified as single-periodic pulsating soliton, double-periodic pulsating soliton and soliton explosion. These pulsations have common features such as energy oscillation, bandwidth breathing and temporal shift. However, the pulse is repeated every two oscillations for double-periodic pulsating soliton. When it comes to soliton explosion, because of the intermittent overdriven nonlinear effect induced by the extreme energy oscillation, the spectrum cracks into pieces at a periodic manner. To the best of our knowledge, it is the first time that both pure soliton pulsations and soliton explosion are observed experimentally in the same fiber laser. The results will enhance a more comprehensive understanding for the soliton pulsating phenomena.