Spatial solitons supported by competing nonlinearities in
double-period QPM-structures
Steffen Kjær Johansen
Department of Informatics and Mathematical Modelling,
Building 321, Technical University of Denmark,
2800 Kongens Lyngby, Denmark
Abstract:
It is well-known that quasi-phase-matching (QPM) gratings on average induce
Kerr-like nonlinearities in quadratic media. However, the influence of
these cubic nonlinearities on soliton formation in actual physical setups
is vanishing. This is due to the dependence on the grating period
which normally is engineered to compensate a very large phase-mismatch
effectively eliminating cubic terms. We report on numerical
experiments in QPM-structures with a superimposed slow second
period. We show theoretically that these structures effectively can be
engineered to mimic a one-period structure at small phase-mismatches
making soliton formation and control supported by competing nonlinearities
practically realizable.