Self-modulation of pulses in Kerr medium and limits of the single-mode approximation

Any nonlinear interaction, in principle, can produce non-classical state. The Kerr nonlinearity seems to be the simplest one. Since papers [1-3], it seemed that as the squeezed states, as the Schriidinger cat ones can be produced by the self-modulation. The squeezing was really observed [ 3] in such a scheme. As for cats, Ref. {4,5] mention the large distance of propagation and linear absorption as factors which make the experimental realization unlike. Note that neither the large distance of propagation nor the linear absorption are fundamental reasons why the Schrodinger cat cannot be obtained by such a manner.