A XIOPM research team report on pulse evolution without wave breaking in a strongly dissipative-dispersive laser system where pulses encounter significant amounts of positive and negative dispersions. In contrast to conventional soliton, dispersion-managed soliton, and self-similar pulse evolutions, a different type of pulse shaping in mode-locked lasers is theoretically investigated and experimentally observed. The pulses of this laser have very low frequency chirp and exhibit as the quasirectangle temporal and Gaussian spectral profiles, and the spectral width is almost independent of the pumping strength. The temporal and spectral widths fluctuate as low as ～3% of the relative fluctuation throughout the laser cavity. Both numerical and experimental results show that the pulses exist with energies much greater than can be tolerated in self-similar pulse shaping.

（Original research article: Phys. Rev. A 81, 053819 . https://doi.org/10.1103/PhysRevA.81.053819）