Binary Darboux transformation and multi-dark solitons for a higher-order nonlinear Schrödinger equation in the inhomogeneous optical fiber

Chong Yang,Xi-Yang Xie

Figure 1. Dark-one solitons via solutions (32) with the parameters: (a) ς = 0, κ = 0.5, η = 1, λ = 0.25, a(x) = 1.1, c(x) = 1.5, f(x) = 2 and $\rho =\tfrac{1}{2}\left(1-\tfrac{\sqrt{3}}{2}{\rm{i}}\right);$ (b) parameters are the same as (a) except for $a(x)=5.5x$.