Quantitative approach to breather pair appearance in nonlinear modulational instability

We investigate the generation of symmetric and asymmetric pairs of breathers from localized disturbances in the nonlinear stage of modulational instability governed by the nonlinear Schrödinger equation. An asymptotic matching approach allows us to predict with great accuracy how their emergence and evolution depend on the parameters of the perturbation. The same approach turns out to be applicable to other classes of perturbations which, due to their different decays in time, do not give rise to breathers.