Transient behaviors of pulse breaking and recovering in a dispersion-managed mode-locked Yb fiber laser

•Transformation from stretched pulses to dissipative solitons in a mode-locked Yb fiber laser is reported for the first time.•Overdriven nonlinear effect triggers wave breaking of SPs, and improved NCD originated from wavelength shift helps self-recovering of DSs.•Numerical simulations confirm experimental observations and bring insights to the understanding of transient nonlinear dynamics. Various pulse regimes have been discovered in mode-locked fiber lasers with carefully designed cavity setups. However, the transitions between different types of stable pulse solutions are rarely observed in a laser with the same cavity configuration. Here, we report on the experimental observation of the transformation from stretched pulses (SPs) to dissipative solitons (DSs) in an all-polarization-maintaining dispersion-managed mode-locked Yb fiber laser for the first time. By means of the time-stretch dispersive Fourier transform technique, the temporal and spectral dynamics of transient behaviors from pulse breaking to pulse recovering are identified in real time. It is revealed that the overdriven nonlinear effect induced by pump increase triggers the wave breaking of SPs, and the improved net-cavity dispersion originated from wavelength shift helps the self-recovering of DSs. Numerical simulations validate the experimental observations and bring insights to the understanding of transient nonlinear dynamics in ultrafast fiber lasers.