Temporal multi-soliton complexes generated by passively mode-locked lasers

Abstract

We review various experimental observations of multiple pulsing in passively mode-locked lasers and give several possible mechanisms that have been addressed in the literature. We then propose some criteria to distinguish dissipative multi-soliton complexes among them, and relate them to the theoretical literature. A particular distributed model, which includes the main laser features usually involved in the formation of multi-soliton complexes, viz. the cubic-quintic complex Ginzburg-Landau equation (CQCGLE), is detailed. We put emphasis on the attractors of soliton pairs, and show that some features predicted by the CQCGLE model are corroborated by experiments in a passively mode-locked fiber laser. However, some other experimental features of soliton pair attractors remain unexplained within the frame of a distributed model. We then develop a more realistic model which includes discreteness and periodicity, and this in turn leads to a large number of soliton pair attractors. The important influence of the dispersion regime is stressed.