Article révisé par les pairs
Résumé : The square-shaped laser pulse propagation in optical fibers was used to demonstrate the Fermi-Pasta-Ulam (FPU) recurrence in modulationally unstable optical waves. The system was found to be dominated by nonlinear Schrodinger equation (NLS). The long-term complex nonlinear nature of light waves was revealed in silica optical fibres. The FPU recurrence was found to be independent of linear attenuation and Raman scattering.