Cascaded nonlinear phase shift in a novel anharmonic phase-mismatch configuration

We theoretically analyze a new class of aperiodic phase mismatch. The phase -matching function that is chosen depends on the calculated second-harmonic amplitude generated in the device during the propagation of the fundamenta l beam at given input intensity and wavelength. We show that, in such a con figuration, the fields evolve toward the eigenmodes of a chi((2)) two-wave mixing process. Hence a constant pump and an enhanced nonlinear phase shift that grows linearly with propagation length are obtained. We also discuss the feasibility of this scheme that provides an alternative approach for th e realization of optical switching devices or Kerr-effect compensators. (C) 1999 Optical Society of America [S0740-3224(99)03511-0].