Evolution dynamics of discrete-continuous light bullets

Abstract

We experimentally and numerically investigate the propagation of light bullets (LBs) excited in two-dimensional fiber arrays. The combination of nonlinear self-frequency shift, wavelength dependence of thedispersion, and the interwaveguide coupling strength induce an adiabatic variation of the parameters of the LBsalong their propagation paths, until they reach the limits of the regime of existence and decay. The relative strengthof the various perturbative effects can partially be controlled by the array’s geometry. The characterization of theLB dynamics is carried out by implementing a spatiotemporal, cross-correlating, and spectrally resolved imagingsystem with femtosecond resolution. The experimental results are in good agreement with the numerical data ifhigher-order nonlinear effects and the wavelength dependence of the dispersion and coupling are included. Theobserved wave packets are linked to the stationary solutions of the simplified nonlinear Schr¨odinger equation.Furthermore, the maximum possible range of existence of LBs in arrays of waveguides is discussed.