Dynamics of spatial soliton in a gradient refractive index waveguide with nonlocal nonlinearity

We study the propagation of a spatial soliton in a triangular gradient refractive index (GRIN) waveguide with nonlocal nonlinearity. Dynamics of such soliton propagation are predicted analytically using equivalent-particle approach. It is shown that without nonlocal nonlinearity the soliton oscillates periodically and symmetrically with the oscillation center exactly at the center of waveguide. Weak nonlocal nonlinearity leads to an asymmetric oscillation of the soliton and also shifts the oscillation center. Stronger nonlocal nonlinearity will produce a soliton exit from the waveguide where the soliton remains stable. Furthermore, a soliton with higher amplitude causes a much bigger nonlocal effect. The dynamics of the soliton are also simulated numerically. The results of our simulations agree very well with our analytical prediction.