Binary Darboux transformation and vector-soliton-pair interactions with the negatively coherent coupling in a weakly birefringent fiber

Soliton-based data transmission provides the hope of surmounting the limitations caused by the dispersion of optical fibers. In this letter, we investigate the coherently coupled nonlinear Schrödinger system with the negatively coherent coupling in a weakly birefringent fiber. With respect to the two interacting modes in the fiber, we construct a binary Darboux transformation with the zero seed solutions, which is different from the existing one, and analytically and graphically study the vector bright solitons and their interactions. Besides the vector degenerate and nondegenerate solitons, the vector soliton pairs are derived with the associated parameter conditions. Two interaction mechanisms between the two degenerate solitons, with the phase shifts or not, are used to explain the elastic and inelastic interactions between the soliton pairs and degenerate solitons. From the elastic interactions between the nondegenerate solitons and soliton pairs, we find that the amplitudes of the formers are changed and converted back to the initial shapes in two components. Elastic interactions between the two soliton pairs are exhibited as well