基于双光子光折变效应的新型空间孤子对

New Type Spatial Soliton Pairs Based on Two-photon Photorefractive Effect

推导了由线性和二次电光效应共同支持的新型空间孤子对解,采用数值模拟法分析了外加电场对亮-亮、暗-暗和亮-暗空间孤子对强度包络的影响.结果表明:与单一非线性效应所支持的孤子对不同,新型亮-亮孤子对在外加电场为正和为负情况下均可以存在,正的外加电场所支持的孤子对宽度略小于相应的负的外加电场情况;对于新型暗-暗孤子对,由于二次电光效应和线性电光效应的机制不同,导致孤子对存在所对应的外加电场强度限定在较低的某一范围内,随着外加电场强度的加大,孤子对的宽度逐渐减小;对于新型亮-暗孤子对,其亮分量峰值一般略大于暗分量峰值,此孤子对在一定的振幅扰动下,当传输距离大于某特定值后会出现传输的不稳定性.

The solutions of new type spatial soliton pairs supported by both linear and quadratic electro- optical effects were deduced theoretically. The influences of external electric field on the intensity envelopes of bright-bright, dark-dark and bright-dark spatial soliton pairs were analyzed by numerical simulation method. The results show that the new type bright-bright soliton pair can exist whether the external electric field is positive or negative, which is different from the soliton pair supported by the sole nonlinear effect. The soliton pair width supported by positive electric field is smaller than that of negative electric field. Because the different mechanism between the quadratic and linear electro-optical effects, the intensity of external electric field is restricted to a low certain range for dark-dark soliton pairs, and its width decrease gradually with the increasing of electric field intensity. For the new type bright-dark soliton pair, the peak of bright component is usually larger than that of dark component and the propagation instability will emerge when the propagation distance exceed a certain value under a certain amplitude perturbation.