Freak Waves as a Result of Modulation Instability

We describe a general N-solitonic solution of the focusing NLSE in the presence of a condensate by using the dressing method. We find a broad class of superregular solitonic solutions which are small perturbations at certain a moment of time. They describe the nonlinear stage of the modulation instability of the condensate and play an important role in the theory of freak waves.