Numerical investigations of interactions among planar bright photorefractive screening solitons

Detailed numerical investigations of the interactions among planar bright photorefractive screening solitons are performed by employing the so-called beam propagation method (BPM). It's found that two in-phase solitons attract each other, and soliton fusions do occur at certain interaction length, which increases monotonously with the initial separation of the two interacting solitons. While in the case of out-of-phase, the two solitons repel each other with a force decreasing monotonously with the initial separation. When the relative phase between the two solitons falls within the ranges of (0, π) and (-π, 0), energy transfer will accompany the interactions. Moreover, interactions among multiple solitons could be qualitatively predicted by analyzing those of the neighboring ones.