Bright solitons in fractional coupler with spatially periodical modulated nonlinearity

We study bright solitons in the fractional coupler with a spatially periodical modulated nonlinearity. The results show that the linear coupling constant kappa, Levy index alpha, chemical potential mu and nonlinear intensity g have a significant influence on the amplitude, width and stability of fundamental solitons, dipole solitons and tripole solitons. We investigate the stability of bright solitons by linear stability analysis and the real-time evolution method. It is found that the bright solitons tend to be stable with the increase of linear coupling constant, Levy index, chemical potential, and nonlinear intensity in the corresponding parameter interval. The results also show that the distance between adjacent peaks is four times of the nonlinear lattice period for dipole solitons and six times for tripole solitons. We also find that the number of soliton peaks is smaller, and the stable region is wider in the fractional coupler with the spatially periodical modulated nonlinear lattice.