非局域非线性耦合器中多极亮孤子的特性

Properties of Multipolar Bright Solitons in Non-local Nonlinear Coupling Medium

研究了一维非局域非线性耦合器中多极亮孤子的存在条件和稳定传输.用牛顿迭代法得到了二极和三极亮孤子.由于较强的非局域响应诱导孤子间的吸引作用比排斥作用大,此时二极孤子不能稳定传输,两孤子相互吸引,融合成一个孤子.随着非局域参数的减小,非线性效应和衍射效应达到平衡时,二极孤子能稳定传播.随着传播常数的减小,孤子的幅值减小,束宽变窄,使得孤子能稳定传播.对于三极亮孤子,在非局域参数较小的时候,耦合的两个三极孤子都不能进行稳定传输.传输一段距离后三极孤子发生碰撞,融合成两极孤子,两极孤子继续传输,最终融合成为一束振荡的光束.随着非局域参数的增大,三极孤子传播的稳定性增强.当传播常数取负数时,随着其绝对值的减小,三极亮孤子的幅值增大,束宽减小,孤子传播的稳定性增强.最后,通过加入白噪声进一步验证了这些亮孤子传播稳定性.

The existence conditions and stable propagation of multipole bright solitons in the one dimensional nonlocal nonlinear couple are reported.By means of Newton iterative method,the dipolar and tripolar bright solitons are obtained.Because the attraction of solitons is larger than their repellant due to the strong nonlocal response,the propagation of the dipolar soliton is unstable,and two solitons attract each other and then merge into one soliton.With the decrease of the nonlocal parameters,the propagations of the dipolar solitons are stable when the balance of the nonlinear effect and diffraction effect is achieving.On the other hand,with the decrease of the propagation constant,the amplitude of solitons increases and the beamwidth is changed to be narrow,the propagation of solitons is stable.For tripolar bright solitons,the coupled tripole solitons can not propagate steadily when the nonlocal parameters are small.After a distance of propagation,the tripole solitons collide and merge into dipolar solitons,finally the dipolar solitons merge into an oscillatory beam.With the nonlocal parameters increasing,the propagation of the tripolar bright solitons come to be more stable.Taking the propagation constant negative and decreasing its absolute value,the amplitudes of solitons increase,the beamwidths decrease,and the propagation stability of the tripole solitons is increasing.Finally,the propagation stability of these bright solitons is further verified by adding white noise.