Abstract

All-optical computing and signal processing using nonlinear guided-wave devices potentially offer high speed and low energy consumption. Efficient control of light by light requires that the product of the nonlinear coefficient (of the waveguide) and the guided-wave intensity be significant. The wavenumber of a nonlinear guided wave, however, is a function of its intensity. The distributive excitation of nonlinear guided waves using a grating is a coherent process. Since the guided-wave amplitude builds up from zero, the local wavenumber of the nonlinear guided wave varies within the extent of the grating. The phase-matching condition for the coherent excitation process can only be satisfied at one location. Theoretical and experimental investigations [1, 2] of the excitation of nonlinear guided waves demonstrate that the excitation efficiency decreases as the incident intensity increases for a fixed nonlinear coefficient. Therefore, even if very highly nonlinear optical materials are available, the above-mentioned product is still limited by the excitation process.

© 1992 Optical Society of America