Collision dynamics of gap solitons in Kerr media

The collision dynamics of counterpropagating gap solitons in a fiber Bragg grating are investigated. In the case of initially in-phase solitons, it is found that the dynamics are more complex and richer than previously reported. An important finding is that, in general, the outcome of the collisions is dependent upon gap soliton parameters (θ, V) and the initial separation of solitons. However, if the solitons are initially very far apart the dependence on the initial separation is negligible. In the case of π-out-of-phase solitons, we find that they generally bounce off each other with negligible radiation as long as the solitons are stable (i.e., 0<θ<π/1.98). When the phase difference is π/2, the emerging solitons travel at different velocities. For large values of θ (i.e., θ>π/1.98) the collision strongly catalyzes the onset of instability and results in the destruction of solitons.