Complex Self-organized Multi-pulse Dynamics in a Fiber Laser: The Rain of Solitons

We present experimental studies of new dynamics observed in a fiber laser operated in a highly-pumped but weakly mode-locked regime. In this situation, both soliton pulses and cw background coexist and interact. In a specific dynamics which we have called "soliton rain", additional solitons arise spontaneously in the cavity rom the fluctuations of a background and drift until they reach a condensed phase of aggregated solitons. This process can go on forever in a quasi-stationary fashion. We have characterized the "soliton rain" dynamics, explored neighboring dynamics, and demonstrated a convenient way to control the soliton rain threshold by injecting an external cw laser inside the fiber laser cavity.