光通信

光传输、通信理论 TN911 2004021404 具有周期非均匀扰动的色散管理系统中的孤子传输=Soliton propagation in a dispersion-managed system with periodically inhomogeneous perturbations[刊,中]／殷德京(湖北师范学院物理系．湖北,黄石(435002)),李宏∥光子学报．—2003,32(6)．—718-722 在准理想的色散管理系统中建立了非均匀扰动模型,研究了它们对孤子传输和相互作用的影响。这些扰动导致孤子崩塌,加剧了孤子间相互作用。它们影响的大小与周期长度和扰动强度有关,并且存在最坏周期长度和扰动共振现象。最后,引入非线性增益和滤波器来有效控制这些扰动的影响。图7参12(严寒)     

亚强非局域空间光孤子的相互作用

研究了亚强非局域空间光孤子的相互作用规律,从光线方程出发得到了孤子光束中心的演化性质以及相互作用周期的解析解.发现亚强非局域条件下孤子的初始间距和非局域特征长度的关系对孤子的相互作用周期有很大的影响,在斜入射时存在一个最大入射角, 小于这个角度孤子才会吸引.数值模拟验证了理论解析的结果. 关键词： 亚强非局域 相互作用 空间光孤子 全光开关     

高码率光孤子传输系统中用光相位共轭补偿高阶扰动

在由分布式掺铒光纤级联的高码率传输系统中存在不可忽略的高阶扰动,它们引起孤子自频率漂移和孤子变形。本文用光相位共轭补偿高阶扰动,结果表明:由分布式掺铒光纤级联的高码率传输系统中,适当选取光相位共轭周期长度,可以完全消除高阶扰动引起的孤子自频率漂移和孤子变形。     

（2+1）维Sawada-Kotera方程中两个Y周期孤子的相互作用

利用双线性方法给出了2+1维Sawaka-Kotera(SK)方程的N孤子解.将N孤子解中的实参数扩大到复数范围，得到了该方程的呼吸子解，描述线孤子和y周期孤子相互作用的解和两个y周期孤子相互作用的解.从解析和几何两个角度探讨了两个y周期孤子的相互作用.相互作用性质和耦合系数有关.对于SK方程，耦合系数的取值只允许方程中存在弹性的排斥相互作用. 关键词： y周期孤子相互作用 SK方程 双线性方法     

受扰动的光纤孤子间的相互作用

基于含扰动的非线性薛定谔方程，发展了高登的光孤子相互作用理论，直接从近似的二孤子解昨到描述实际光纤通讯中孤子间的相互作用的解析公式，公式表明在实际的通讯系统中光纤孤子间的相互作用不令依赖于它们之间相对相差，而且依赖于它们的相对能量，速度差随传输距离的变化。     

随机双折射光纤中孤子相互作用及控制

利用分步傅里叶方法,对随机双折射光纤孤子传输进行了数值模拟,研究了多孤子间相互作用;分析了随机双折射现象对孤子传输的扰动机制、稳定性以及辐射能量特性.结果表明:随机双折射引起孤子传输不稳定,增强了孤子间相互作用,导致孤子能量辐射并随传输距离增大.引进非线性增益增强滤波器的控制作用可以有效地抑制随机双折射的对孤子相互作用的影响.     

光诱导平面波导阵列中离散空间光孤子的相干相互作用

采用Petviashvili迭代法对光诱导平面波导阵列中的一维离散空间光孤子进行求解，利用分步束传播法对离散空间光孤子间的相干相互作用进行了详细的数值模拟.探讨了离散孤子间的相位差、孤子光强、波导阵列写入光的强度和周期以及外加电场对相互作用过程的影响.结果表明：离散孤子间的相位差对相互作用的影响与连续介质中的情况类似，不同相位差情况下的相互作用也表现为吸引、排斥以及能量转移等现象.同时，离散孤子间的相干相互作用过程(如融合距离和排斥间距等)均会受到孤子光强、波导阵列写入光的强度和周期以及外加电场大小的影响 关键词： 光诱导平面波导阵列 离散空间光孤子 相干相互作用     

开环系统中灰光伏孤子的时间及演化特性分析

分析了开环系统中一维灰光伏孤子的时间特性.基于与时间相关的演化方程,用数值方法得到了准稳态和稳态的灰孤子解,分析了形成准稳态灰孤子的物理机制.结果显示准稳态灰孤子的宽度是与光强无关的,并且它们的形成时间和孤子的峰值与背景辐射强度比成反比.这些性质与开环系统中的亮、暗孤子的性质很相似.同时采用波传播的数值解法,分析了它们的传播特性,结果显示它们在小于10％的扰动下是相对稳定的.     

扩散效应对光伏孤子相互作用的影响

用数值方法研究扩散效应对两个平行传播相干光伏孤子光束相互作用的影响. 结果表明，在扩散效应的影响下，两相干孤子光束同相相互作用不是使它们相互融合, 而是使它们趋向相互分离，且光束之间存在能量耦合；异相孤子相互作用不再是简单地互相排斥，在一定的条件下，两光束既互相排斥，又同时向同侧偏转. 关键词： 光伏空间孤子 相干相互作用 扩散效应     

自散焦非局域非线性材料中的光学涡旋孤子

通过数值模拟的方法对非局域非线性自散焦材料中的光学 涡旋孤子的传输特性以及相互作用特性进行了研究. 研究表明, 拓扑荷|m|=1的非局域涡旋孤子是稳定的, 而拓扑荷|m|>1的非局域涡旋孤子均具有拓扑不稳定性. 在微扰存在的情况下以及在近距离相互作用的过程中, |m|>1的涡旋孤子会分裂成一系列的|m|=1的涡旋孤子. 非局域涡旋孤子与局域涡旋孤子具有相同的长距离相互作用模式, 即点涡旋相互作用模式. 但两者的短距离相互作用存在一些差别, 在相同的距离下, 两涡旋间的相互绕转的周期随着材料的非局域响应长度增大而增大. 关键词： 非局域非线性薛定谔方程 自散焦 涡旋孤子     

Effects of correlated perturbations on dark soliton propagation and interaction

Correlated perturbations are considered in a dark soliton system, and their effects on soliton propagation and interaction are investigated numerically. These perturbations result in large sidebands, lead to submergence of dark soliton, and enhance the interaction. The correlation amplifies these effects and shortens the distance until submergence. The comparison of the distinction is made between the degradations of these effects on dark soliton and the corresponding bright soliton. It is found that these effects on dark soliton are less than those on bright soliton. Finally the nonlinear gain is introduced to suppress efficiently these effects.     

Correlation between randomly varying birefringence and random dispersion map in a dispersion-managed soliton system

The correlation between perturbations caused by randomly varying birefringence and a random dispersion map is considered in a dispersion-managed soliton system, and their effects on soliton propagation and interaction are investigated numerically. These perturbations lead to the disintegration of a soliton, and enhance the interaction between solitons. The correlation plays an important role, and reinforces these effects. Furthermore, there is a stochastic resonance between two perturbations in the system; here the effect is the largest, and the corresponding distance until disintegration is the shortest. Finally, nonlinear gain and a filter are introduced to effectively suppress these effects.     

Dark soliton interaction in optical time division multiplexed system with randomly varying birefringence and random dispersion map

Correlated perturbations caused by both randomly varying birefringence and random dispersion map are considered in optical time division multiplexed dispersion-managed dark soliton system, and their effects on soliton interaction are investigated numerically. These perturbations enhance soliton interaction, and their effects relate to the strength of perturbation, separation, and pulse width. The correlation plays an important role and reinforces these effects. Moreover, there is a stochastic limit between two perturbations in the system, where the effect is the largest and the corresponding interaction distance is the shortest.     

单模阶梯光纤中孤立波的弹性形变双折射及偏振色散

本文利用微扰计算综合考虑了弹性形变对孤立波在单模光纤中传输的影响,指出了即使是孤立波也存在着弹性形变双折射和偏振色散。     

Nonlinear theory of transverse perturbations of quasi-one-dimensional solitons

An averaged variational principle is applied to analyze the nonlinear effect of transverse perturbations (including diffraction) on quasi-one-dimensional soliton propagation governed by various wave equations. It is shown that parameters of the spatiotemporal solitons described by the cubic Schrödinger equation and the Yajima-Oikawa model of interaction between long-and short-wavelength waves satisfy the spatial quintic nonlinear Schrödinger equation for a complex-valued function composed of the amplitude and eikonal of the soliton. Three-dimensional solutions are found for two-component “bullets” having long-and short-wavelength components. Vortex and hole-vortex structures are found for envelope solitons and for two-component solitons in the regime of resonant long/short-wave coupling. Weakly nonlinear behavior of transverse perturbations of one-dimensional soliton solutions in a self-defocusing medium is described by the Kadomtsev-Petviashvili equation. The corresponding rationally localized “lump” solutions can be considered as secondary solitons propagating along the phase fronts of the primary solitons. This conclusion holds for primary solitons described by a broad class of nonlinear wave equations.     

Effects of Periodically Inhomogeneous Birefringence on Dark-Bright Vector Soliton Propagation and Interaction

The effects of periodically inhomogeneous birefringence on dark-bright vector soliton propagation and interaction are investigated by the numerical method. The birefringence leads to the submergence of the dark soliton and the disintegration of the bright soliton, and enhances the interaction between the neighbouring solitons. The system performance is determined by the bright soliton because the dark soliton has robust features. Finally, the avoidance and the effective control are introduced, and the controlling mechanism is demonstrated.     

Effects of varying nonlocality on dynamics of two-component vector spatial solitons

The randomly and the periodically varying weak nonlocalities are investigated by the variational approach in the self-focusing nonlinear media, and their effects are analyzed on the propagation and interaction of the two-component spatial solitons. The results show that they lead to the soliton disintegration and enhance the interaction between the spatial solitons, and their effects depend on the fluctuation strength and the period length of the varying nonlocalities. Finally, the numerical results confirm the theoretical findings.     

Stochastic perturbation in quasi—ideal dispersion—managed soliton system

The model of stochastic perturbation is built up systematically in quasi-ideal dispersion-managed soliton system,its influence on soliton propagation is investigated by both the variational approach and the numerical simulation,and it is found that the stochastic perturbation leads to disintegration of soliton and enhances the interaction between solitons.The nonlinear gain and filter are introduced to suppress effectively the influence on both soliton propagation and interaction.