Publications

Dissipative solitons are self-localized structures that can persist indefinitely in open systems driven out of equilibrium. They play a key role in photonics, underpinning technologies from mode-locked lasers to microresonator optical frequency combs. Here we report on experimental observations of spontaneous symmetry breaking of dissipative optical solitons. Our experiments are performed in a nonlinear optical ring resonator, where dissipative solitons arise in the form of persisting pulses of light known as Kerr cavity solitons. We engineer symmetry between two orthogonal polarization modes of the resonator and show that the solitons of the system can spontaneously break this symmetry, giving rise to two distinct but co-existing vectorial solitons with mirror-like, asymmetric polarization states. We also show that judiciously applied perturbations allow for deterministic switching between the two symmetry-broken dissipative soliton states. Our work delivers fundamental insights at the intersection of multi-mode nonlinear optical resonators, dissipative structures, and spontaneous symmetry breaking, and expands upon our understanding of dissipative solitons in coherently driven Kerr resonators.

Waves that tend to steepen and then break beyond are familiar phenomena encountered in nature, looking for instance sea waves approaching a coast. Less common scenarios are the formation of a vertical front followed by the spontaneous emission of fast expanding wave trains, so called undular bores or dispersive shock waves. Spectacular evidences of such type of behaviors in nature are atmospheric gravity waves: “morning glory clouds” or large tidal waves traveling up-stream river estuaries: “the Mascaret”. The basic ingredients underlying such phenomena are the nonlinearity of the medium that induces the initial steepening combined with a weak dispersion that drives the undular bore formation in nearly conservative conditions. Such regime can be also encountered for light waves, e.g. for an intense pulse propagating along an optical fiber with normal chromatic dispersion or for a laser beam propagating in a medium with nonlinear response of defocusing type. In this paper, we report the first experimental observation of optical undular bores in a fiber-based system. We present strong evidence for a novel dynamics where the overall optical field behaves as a fluid undergoing the formation of an array of twin shock points from which multiple temporal undular bores emerge, forming a complex pattern due to unavoidable collisions of adjacent undular bores.