Enhancement of chi((2)) cascading processes in one-dimensional photonic bandgap structures

We theoretically analyze the nonlinear phase shifts induced by cascaded chi ((2)):chi((2)) processes in one-dimensional photonic bandgap structures. We find that the enhancement of the density of modes near the band edge, coup led with a suitable choice of relative phase mismatch, leads to a remarkabl e new effect: The relative phase shift of the fundamental field on transmis sion can be of the order of pi over a distance of 7 mu m, with input intens ities of the order of only 10 MW/cm(2). (C) 1999 Optical Society of America .