BIOCHROMATIC WAVE-PROPAGATION IN PERIODICALLY POLED MEDIA

The energy-exchange process between the fundamental and its second-har monic fields copropagating in an optical medium is facilitated by the spatially periodic dc poling field. The nonlinear dynamics of this sys tem is investigated in the context of an effective Hamiltonian formali sm. The explicitly included cross-modulation and self-phase-modulation nonlinear terms lead to the bifurcation instability interpreted as a new switching phenomenon in which both up- and down-conversion efficie ncies can be precisely controlled by the external field. Experiments t esting predicted effects are suggested.