中文摘要：

建立了光折变晶体在外加直流电场作用下的光传输理论模型，运用分步傅里叶方法对传输方程进行了数值分析。结果表明：一阶亮孤子在光折变晶体中稳定传播，二阶亮孤子发生周期性的振幅变化；一阶亮孤子对在光折变晶体中发生周期性耦合作用，耦合周期与孤子对输入脉冲的中心距离有关，距离越大，耦合周期越长；二阶亮孤子对同样发生耦合，耦合周期也取决于输入脉冲的中心距离，同时每一个二阶亮孤子会发生分裂，分裂成一大一小两个孤子；此外，在同样的中心距离下，二阶亮孤子对的耦合周期比一阶亮孤子对短。

英文摘要：

To analyze the properties of bright screening spatial soliton in photorefractive crystals under DC field, the propagation equation is gotten and calculated with split-step Furier method. When the two soliton waves are incidented into the photorefractive crystal and the distance between them is changed, the evolutionary nde of the bright soliton and soliton pairs is gotten. Both first-order and second-order bright soliton can transmit stably in the photorefractive crystals. When the incidented waves are changed in the form of soliton pairs, the solitonpairs will interact and couple each other in different periods according to the distance between the two soliton waves and the order of the soliton pairs. At the same time, each soliton of the second-order soliton pairs splits into two fundamental solitons that one is bigger and another smaller.