Soliton dynamics in periodically modulated directional couplers

Abstract
Using the variational approximation, we analyze the evolution of solitons in a twin-core nonlinear optical fiber whose coupling coefficient has both constant and spatially periodic parts. The influence on switching of direct and parametric resonances between the period of the energy oscillation within the coupler and the periodic modulation is considered, as is the influence of the modulation on a bifurcation that splits the stationary symmetric soliton into a pair of asymmetric ones.