Families of fundamental and multipole solitons in a cubic-quintic nonlinear lattice in fractional dimension

摘要

We construct families of fundamental, dipole, and tripole solitons in the fractional Schrodinger equation (FSE) incorporating self-focusing cubic and defocusing quintic terms modulated by factors cos(2) x and sin(2) x, respectively. While the fundamental solitons are similar to those in the model with the uniform nonlinearity, the multipole complexes exist only in the presence of the nonlinear lattice. The shapes and stability of all the solitons strongly depend on the Levy index (LI) that determines the FSE fractionality. Stability areas are identified in the plane of LI and propagation constant by means of numerical methods, and some results are explained with the help of an analytical approximation. The stability areas are broadest for the fundamental solitons and narrowest for the tripoles. (C) 2020 Published by Elsevier Ltd.