DEPTH PROFILE OF THE NONLINEAR-OPTICAL SUSCEPTIBILITY OF ION-IMPLANTED KNBO3 WAVE-GUIDES

We report on the depth profile of the nonlinear optical susceptibility in ion-implanted potassium niobate (KNbO3) waveguides using reflected second harmonic generation from wedged samples. After irradiation the waveguide layer exhibits partial loss of its optical nonlinearity tha t can be recovered to better than 90% of its value of the virgin cryst al by subsequent annealing and repoling. We propose microscopic depola rization due to ion implantation to be responsible for the observed de crease of the nonlinear optical susceptibility. (C) 1995 American Inst itute of Physics.