Dispersive Fourier transform characterization of multipulse dissipative soliton complexes in a mode-locked soliton-similariton laser

We use the dispersive Fourier transform to spectrally characterize ``multipulse soliton complexes'' in a dissipative soliton fiber laser operating in the soliton-similariton regime. These multipulse complexes consist of two or more circulating dissipative solitons of picosecond duration, but with temporal separations of similar to 5-40 ns, three orders of magnitude greater than the individual pulse durations. The results we present include a multipulse complex of 9 distinct single soliton pulses with similar to 10 ns separation, as well as a multipulse complex where a soliton molecule of two bound pulses separated by similar to 40 ps coexists with multiple single pulses with separations of similar to 30 ns. We also use the dispersive Fourier transform to characterize breathing and transition dynamics in this multipulse regime, and our results add further to the experimental characterization of the diverse range of nonlinear structures in dissipative soliton systems. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement