Autoresonant dynamics of optical guided waves.

We study, theoretically and experimentally, autoresonant dynamics of optical waves in a spatially chirped nonlinear directional coupler. We show that adiabatic passage through a linear resonance in a weakly coupled light-wave system yields a sharp threshold transition to nonlinear phase locking and amplification to predetermined amplitudes. This constitutes the first observation of autoresonance phenomena in optics.