Dark solitons in the inhomogeneous optical fiber are studied in this manuscript via a higher-order nonlinear Schrdinger equation, since dark solitons can be applied in waveguide optics as dynamic switches and junctions or optical logic devices. Based on the Lax pair, the binary Darboux transformation is constructed under certain constraints, thus the multi-dark soliton solutions are presented. Soliton propagation and collision are graphically discussed with the group-velocity dispersion, third- and fourth-order dispersions, which can affect the solitons’ velocities but have no effect on the shapes. Elastic collisions between the two dark solitons and among the three dark solitons are displayed, while the elasticity cannot be influenced by the above three coefficients.

由于可以将暗孤子作为动态开关和结或光学逻辑器件应用在波导光学中，因此本文通过高阶非线性Schrdinger方程研究了不均匀光纤中的暗孤子。基于Lax对，在一定约束条件下构造了二进制Darboux变换，从而提出了多暗孤子解。用群速度色散，三阶和四阶色散以图形方式讨论了孤子的传播和碰撞，这可以影响孤子的速度，但对形状没有影响。显示了两个暗孤子之间以及三个暗孤子之间的弹性碰撞，而弹性不受上述三个系数的影响。