Observation of four Fermi-Pasta-Ulam-Tsingou recurrences in an ultra-low-loss optical fiber

We report the experimental observation of more than four Fermi-Pasta-Ulam-Tsingou recurrences in an optical fiber thanks to an ultra-low loss optical fiber and to an active loss compensation system. We observe both regular (in-phase) and symmetry-broken (phase-shifted) recurrences, triggered by the input phase. Experimental results are confirmed by numerical simulations. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement