Experimental tweaking of symmetry breaking in recurrent nonlinear modulational instability

We show that the nonlinear stage of the universal phenomenon of modulational instability, and in particular its recurrent behavior, is deeply affected by arbitrarily weak losses. Indeed linear damping leads to spontaneous breaking of the recurrence symmetry through separatrix crossing occurring at multiple critical values of the attenuation, across which the dynamics switches between two types of recurrence exhibiting dramatic slowing down. We provide experimental evidence for this phenomenon in a fiber optics experiment designed in such a way that the effective losses can be carefully tailored by techniques based on Raman amplification.