Solitons and Dissipative Solitons for Ultrafast Lasers

Ultrafast fibre lasers have been developing at an accelerated pace during the past two decades, as a result from both technological and conceptual advances. This chapter emphasizes on the latter. It presents the key enabling concepts that have allowed the development of innovative cavity architectures supporting original pulse dynamics, including energetic short pulses in fibre laser cavities using standard telecom-grade components. Popular techniques of passive mode-locking for fibre lasers are introduced, based on either saturable absorber materials or non-linear interferences. The concept of a soliton laser is presented with its energy scaling and dispersive wave radiation features. Going beyond, the dissipative soliton paradigm is introduced, explaining the stable propagation of high-energy chirped-pulses in laser cavities endowed with normal dispersion, as well as the pattern formation of soliton molecules. The dissipative soliton paradigm encompasses a diversity of self-consistent ultrafast cavity dynamics such as the self-similar evolution followed by filtering, multicolour Raman dissipative solitons, dissipative soliton resonance, and even incoherent noise-like pulse emission. Finally, an outlook is provided, mentioning hot emerging topics such as smart lasers and spatiotemporal lasers.