Propagation and interaction of second-order solitons

The propagation characteristics of second-order solitons were acquired by solving the nonlinear Schrodinger (NLS) equation with the method of step Fourier transform. The second-order solitons are compressed and their amplitude oscillates during the propagation. Periodic collision does not take place during propagation process of two second-order solitons. Two secondorder solitons will periodically yield a smaller soliton when their time-interval is small enough. It is concluded that the propagation characteristics of secondorder soliton are different from those of one-order soliton.