All-optical switching via second harmonic generation in a nonlinearly asymmetric directional coupler

Taking advantage of the nonlinear phase-shift obtainable via up- and down-conversion of a beam to and from its second- harmonic, an efficient all-optical switch can be realized adopting the standard directional coupler configuration with strong nonlinear asymmetry. Using coupled-mode theory we numerically demonstrate power switching in a half-beat length coupler with remarkable functional characteristics in a wide range of parameters.