Polariton superregular breathers in a resonant erbium-doped fiber

Abstract

We study polariton superregular (SR) breathers triggered by the resonant interaction of an optical field with two-level doping ions in an erbium-doped fiber. We demonstrate explicitly that the optical wave component always features a bright structure that describes the modulation instability (MI) development from localized small perturbations, while the SR matter-wave breathers exhibit more complicated dynamical evolution, which are absent in standard scalar SR breather theory. Despite the complexity, the exact link between these SR breathers and MI is established strictly by showing that the absolute difference of group velocities of SR breathers coincides exactly with the linear MI growth rate. In particular, we show how a small dip perturbation of the dark SR breather in the matter wave component induces an intriguing MI process of completely exponential decay. These results will enrich our understanding on the MI development in complex coupled light-matter interaction systems.