Multi-wave coupled interactions in aperiodically poled nonlinear crystals

We consider implementation of coupled nonlinear optical processes in aperiodically poled nonlinear crystals which can be produced by the method of the nonlinearity modulation superposition. The wave interaction consisting of three three-frequency processes with multiple frequencies, is analyzed in detail. It is shown that under certain conditions the superposition of waves, generated in this case, can form the light pulses with subfemtosecond duration.