Ricerc@Sapienza

The buildup process of coherent structures and patterns from the composite balance between conservative and
dissipative effects is a universal phenomenon that occurs in various areas of physics, ranging from quantum
mechanics to astrophysics. Dissipative solitons are highly coherent solutions of nonlinear wave equations, and
provide an excellent research platform for ultrafast transient phenomena. Herein, by taking advantage of the fast
detection technique provided by the dispersive Fourier transform, we experimentally observe the spectral

We introduce a mechanism of stable spatiotemporal soliton formation in a multimode fiber laser. This is based
on spatially graded dissipation, leading to distributed Kerr-lens mode locking. Our analysis involves solutions of
a generalized dissipative Gross-Pitaevskii equation. This equation has a broad range of applications in nonlinear
physics, including nonlinear optics, spatiotemporal pattern formation, plasma dynamics, and Bose-Einstein
condensates. We demonstrate that the careful control of dissipative and nondissipative physical mechanisms

A two-level iterative algorithm for finding stationary solutions of coupled nonlinear Schrödinger equations describing the propagation dynamics of an electromagnetic pulse in multimode and multicore optical fibers of various structures was developed and tested. Using as an example the proposed analytical soliton solution which is localized in space and time, test calculations were performed, and the convergence of the algorithm was demonstrated.

We experimentally demonstrate simultaneous spatial and temporal compression in the propagation of light pulses in multimode nonlinear optical fibers. We reveal that the spatial beam self-cleaning recently discovered in graded-index multimode fibers is accompanied by significant temporal reshaping and up to fourfold shortening of the injected subnanosecond laser pulses.