General N-dark vector soliton solution for multi-component defocusing Hirota system in optical fiber media

In the normal dispersion regime of optical fibers with third-order dispersion and self-steepening higher-order effects, the propagation of ultrashort pulses is govern by the multi-component defocusing Hirota system. The general N-dark vector soliton solution is firstly constructed by the binary Darboux transformation. From obtained multi-dark soliton solutions, it is found that the collisions between or among vector dark solitons in this multi-component system are elastic, and vector dark solitons retain their shape and intensity only with a slight change in their phase. The results might be useful for applications about vector dark soliton in fiber directional couplers, optical switching and quantum information processors.