Abstract

We consider effects of inter-species attraction on two-component gap solitons in the binary BEC with intra-species repulsion, trapped in the one-dimensional optical lattice. Systematic simulations of the coupled Gross-Pitaevskii equations corroborate an assumption that, because the effective mass of solitons is negative, the inter-species attraction may split the two-component soliton. Two critical values of the lattice strength are identified. Two-species gap solitons are stable in strong lattices. In an intermediate region the soliton splits into a double-humped state with separated components. Finally, in weak lattices, the splitting generates a pair of freely moving single-species solitons.

© 2007 Optical Society of America