Experimental observations of soliton explosions in ultrafast fibre lasers (Conference Presentation)

A soliton explosion is a dramatic effect, whereby a pulse circulating in a mode-locked laser dissipates and then remarkably reforms within a few roundtrips. Our group recently reported the first observation of such explosions in an all-fibre laser. Here, we expand on our initial work, reporting a detailed numerical and experimental study of the dynamics and characteristics of soliton explosions. Our experiment is based on a passively mode-locked Yb-doped fiber laser, where explosions occur close to the boundary between stable and noise-like operation. To capture the events, we use the dispersive Fourier transformation to record, in real time, the pulse-to-pulse spectra emitted by the laser. We explore a variety of operating conditions by systematically adjusting the laser pump power and its cavity length. We also use a realistic model based on a set of generalized nonlinear Schrodinger equations to simulate the explosion dynamics. We find that the explosion dynamics can be influenced by adjusting the operating conditions. As a general trend, the frequency of the events increases as the conditions move closer to the boundary of unstable operation. In fact, when sufficiently close to the boundary, the “explosions” can even become more frequent than ordinary pulses. Moreover, our simulations reveal that complex features in the spectral and temporal profiles of the explosion events can be explained in terms of a multi-pulsing instability. Finally we have examined how the statistics of the events depend on the laser geometry and also whether such explosions indicate the existence of a “strange attractor”.