Dynamics of Temporal Kerr Cavity Solitons: Chaos, Instability, and Multi-Resonant Solutions

Abstract

In this thesis we investigate and report on new experimental observations of the dynamics of temporal cavity solitons in a coherently driven passive Kerr cavity. We report observations of new unstable and chaotic regimes of temporal cavity solitons as they exist when the cavity is driven by a very high power as predicted by the Lugiato- Lefever Equation. Flat-top nanosecond pulses are used in order to reach these very high pumping powers. We use the act of scanning over the cavity resonance in order to both excite the cavity solitons and to observe them at specific detunings from resonance. We observe chaotic breathing patterns and spontaneous self-collapse of cavity solitons. Observations are also captured of a cavity soliton forming localised spatio-temporal chaos in the form of a spontaneous excitation chain-reaction. This phenomenon constitutes a bistable state of a localised chaotic MI pattern existing surrounded by a homogeneously stable CW solution. Both of these categories of chaotic dynamics have never been observed before in any type of optical soliton. When the pump power is pushed even higher, the Kerr Tilt of the nonlinear bistable resonance become greater than the FSR of the cavity. This allows for coexistence between intra-cavity field solutions associated with two resonances. We conduct an investigation into the existence of a ‘super’ cavity soliton existing in this new tristable region in a highfinesse fibre-ring cavity. Simulations show it to be unstable as a result of stimulated Raman scattering causing a self-frequency shift of the cavity soliton at very high detunings. In a medium-finesse fibre cavity, we present never before seen experimental observations of the coexistence between a strongly detuned cavity soliton associated with one resonance, and an MI pattern associated with a second resonance. An interaction is observed between these two nonlinear states through the Raman self-frequency shift. In the highfinesse cavity we conduct a measurement of this Raman self-frequency shift as a function of detuning and find a definite quadratic relationship.