The nonlinear interaction of waves in strongly inhomogeneous media

Nonlinear three-wave interaction in a randomly inhomogeneous, dispersive medium is considered. A kinetic equation for the probability distribution of the second harmonic intensity is obtained in the diffusion approximation. It is shown that the random mismatch of wave phases, which violates the phase synchronism condition, leads to the weakening of the nonlinear interaction and to its stabilization; this effect may be observed in an optical frequency doubler. The dynamics of the transition of the nonlinear interaction to the steady state is analyzed.