In this paper, derive the evolution equations for the parameters of the bright-soliton-like pulses in optical fibers by means of variational method from the MNLS equation.

• 摘要本文从含修正的非线性薛定谔方程出发，采用变分法，导出了三阶色散情况下光纤中类明孤子参数随传输距离的演化方程组；