光纤中随时间变化的三阶非线性对类明孤子传输特性的影响

Influence of time-varying third-order nonlinearity on propagation properties of bright soliton-like in optical fiber

为了研究在光纤中光孤子的传输特性,将三阶非线性视为微扰作用,由修正的非线性Schr(o|¨)dinger方程(MNLS)寻求类明孤子的尝试解,采用变分法求得拉格朗日密度函数表达式,在此基础上推出了类明孤子的脉冲参数随传输距离的演化方程组。分析讨论了微扰的直接作用和微扰通过a、b、ω、ξ产生的间接作用,用Matlab软件作出图像给出参数|b|随a变化、ξ随β和Z变化、ω随β和Z变化、a随b和Z变化等情形,直观反映出三阶微小量对类明孤子传输特性的影响.

To study the propagation properties of optical soliton in optical fiber, the third-order nonlinearity effect is regarded as the small disturbance. The attempted bright soliton-like solution is obtained from modified nonlinear Schrodinger equation （MNLS）. The Lagrangian density function expression is obtained by using calulus of variational method, from which the evolution equation for the parameter of the optical soliton-like pulse evolving on the propagation distance are derived. Then the direct and indirect effects of small disturbance via a, b, ω, ξare analyzed and discussesd. The profiles of the evolution are made by the Matlab software, which show the relation of ｜b｜ with a, ξ with β and Z, w with β and Z, a with b and Z.