Excitation regeneration in delay-coupled oscillators

A network of phase-coupled oscillators constitutes a system in which excitable 2 pi phase slips can be induced by noise. We show that such an excitation in one of the oscillators can be regenerated by subsequent oscillators and become self-sustained for certain topologies. We focus on the simplest such topology: two mutually coupled oscillators. Our analysis is bolstered by an experimental confirmation of the phenomenon via a pair of mutually delay coupled quantum-dot lasers. Both the intensities and phases of the laser outputs were measured confirming the interpretation.