Noise-seeded spatio-temporal modulation instability in normal dispersion
  In optical second harmonic generation with normal dispersion, the virtually infinite bandwidth of the unbounded, hyperbolic, modulational instability leads to quenching of spatial multi-soliton formation and to the occurrence of a catastrophic spatio-temporal break-up when an extended beam is let to interact with an extremely weak external noise with coherence time much shorter than that of the pump. 
D. Salerno, O. Jedrkiewicz, J. Trull, G. Valiulis,, Antonio Picozzi   and P. Di Trapani