Abstract

Gap solitons are known to exist in configurations where the dispersion is created by the coupling of two waves with strongly different group velocities and the material exhibits a cubic nonlinearity [1,2]. Usually, this coupling emerges in periodically corrugated waveguides (Bragg gratings) where the forward and backward waves are coupled. Recently, it has been shown that spatial solitons may also exist due to quadratic nonlinearities [3]. In this environment temporal solitons suffer from the pulse walk-off and could not be experimentally observed until now. Hence, the question arises whether gap solitons may be supported by quadratic nonlinearities and how they are affected by the pulse walk-off. These are the subjects we are addressing in this paper.

© 1996 Optical Society of America