Noisy soliton pulsation and its dynamics in a mid-infrared ultrafast fiber laser

Abstract

We demonstrate the real-time dynamics of a unique pulsating soliton state featuring noisy behaviors in a mid-infrared ultrafast fiber laser at 2 μm. By virtue of the time-stretch dispersive Fourier transform method, the pulsating behaviors of the noisy solitons are investigated. We find that the noisy pulsating solitons are characterized by a special optical spectrum. The shot-to-shot spectra and pulse energy of these pulsating noisy pulses can evolve periodically with the roundtrips. Besides, the real-time optical spectra within a single period exhibit irregular fluctuations in terms of the spectral profile and intensity, suggesting that the pulsating solitons are made up of noisy wave packets with chaotic features. These results can further enrich the pulsating soliton dynamics and also give new insights into the nonlinear pulse dynamics of mid-infrared ultrafast fiber lasers.