Solitons resonant behavior for a waveguide directional coupler system in optical fibers

A nonlinear waveguide directional coupler system in optical fibers is investigated. The system can be modelled as coupled nonlinear Schrödinger equations. Applying Hirota bilinear transformation method, analytic one- and two-soliton solutions are constructed. Furthermore, a novel class of solitons resonant behavior is observed. The solitons are split into multiple wave peaks around colliding point. The impacts of main parameters on soliton collisions are systematically discussed. Group velocity dispersion parameter and group velocity mismatch parameter can impact and control the resonant effects. Meanwhile, the complex parameters in the soliton solutions can determine resonant peaks intensity.