TY - JOUR AB - Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides. AU - Husko, Chad AU - Wulf, Matthias AU - Lefrançois, Simon AU - Combrié, Sylvain AU - Lehoucq, Gaëlle AU - De Rossi, Alfredo AU - Eggleton, Benjamin AU - Kuipers, Laurens ID - 1429 JF - Nature Communications TI - Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides VL - 7 ER -