The nonlinear dynamical behavior of parametric wave-wave interactions
is studied. The temporal dynamics of the model equations describing re
sonant coupling of two wave triplets in a quadratic nonlinear medium i
s analyzed. This Hamiltonian system is shown to undergo transition fro
m regular to chaotic states via the route of quasiperiodicity. Applica
tion to nonlinear optics in plasmas is exemplified.