Soliton dynamics in directional couplers with variable coupling

The problem of soliton propagation in a system of tunnel-coupled fibers in the case when a coupling parameter depends on a coordinate along a fiber is considered. It is shown, that at periodic modulation of coupling both the parametric resonance of solitons and their dynamic stochastization are possibly depending on the initial conditions, while in the case of a random coupling parameter the stochastic parametric resonance of solitons arises.