KTP离子交换光波导及特性

报道了制备Ｚ－切ＫＴＰＲｂ／Ｂａ离子交换平面光波导的方法，给出了较理想的Ｒｂ和Ｂａ的ｍｏｌ％比，测量了光波导层的光损伤感度和晶格常数变化。实验结果表明：光损伤感度为１．２～２．３×１０－１０ｃｍ２／Ｊ，它与掺Ｂａ的含量和热退火工艺无关；晶格常数的变化为０．４２～０．２５％，它随着掺Ｂａ含量的增加而减少。     

Influence of Stochastic High-Order Perturbations on Soliton Transmission System

The influence of stochastic high-order perturbations on soliton transmission system is studied by self-companying operator method. Arrival time jitters variation induced by stochastic third-order dispersion is approximately proportional to three powers of transmission distance, that by stochastic nonlinear dispersion and self-steeping are approximately proportional to the transmission distance.     

The Influence of Dispersion Stochastic Variation on Bright Soliton Transmision System

ＴｈｅＩｎｆｌｕｅｎｃｅｏｆＤｉｓｐｅｒｓｉｏｎＳｔｏｃｈａｓｔｉｃＶａｒｉａｔｉｏｎｏｎＢｒｉｇｈｔＳｏｌｉｔｏｎＴｒａｎｓｍｉｓｉｏｎＳｙｓｔｅｍＬＩＨｏｎｇＹＡＮＧＸｉａｎｇｌｉｎ（Ｄｅｐｔ．Ｅｌｅｃｔｒｏｎ．Ｅｎｇ．ＳｏｕｔｈｅａｓｔＵ...     

随机色散对孤子传输系统时间抖动影响

在分布放大传输系统中建立了随机色散模型,利用自伴算符法研究了随机色散的影响。结果表明:随机色散与放大的自发辐射噪音联合作用增大了传输系统的时间抖动,其中与传输距离有关的随机色散具有长距离效应,而与孤子频移有关的随机色散具有短距离效应。     

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.     

Time Jitters Caused by Randomly Varying Birefringence in Soliton Transmission System

Soliton propagation in fiber with randomly varying birefringence is studied by using self-companying operator method. It is shown that randomly varying birefringence leads to time jitters increasing with transmission distance, and disrupts the stability of soliton transmission. The fluctuation of time jitters is stochastic, and nonlinear gain is introduced to remove the influence.     

Influence of Stochastic Refractive Index Variation on Time Jitters

The model of stochastic refractive index variation is built in dark soliton transmission system, its influence is studied on time jitters. The results show: the stochastic variation apparently leads to the time jitters in arrival, and reduces the stability and the capacity of the transmission system.     

内脉冲拉曼散射效应对暗孤子传输系统的影响及其抑制

利用守恒量扰动法，研究了内脉冲拉曼散射效应对暗孤子脉冲到达检测窗口时间抖到、传输系统误码率的影响。结果表明，内脉冲拉曼散身效应对暗孤子速度产生了影响，引起了暗孤子传输系统的平衡点漂移，并与放大器噪声联合作用增大了暗孤子脉冲到达时间的抖动，恶化了系统的误码率，限制了系统的传输距离。引入非线性增益可以有效３内脉冲拉曼散身效应对暗孤子传输系统的不良影响。     

The influence of stochastic filter effect on soliton transmission system

The model of stochastic filter effect is built in soliton transmission system, the influence is studied of the stochastic filter effect on soliton transmission system. The results show: the stochastic filter effect leads to the time jitters in arrival, and reduces the capacity of soliton transmission system. Enhancing the strength of filter can suppress well the influence.     

The Fiber Soliton Communication System with Stochastic Variation of Gain

ＴｈｅＦｉｂｅｒＳｏｌｉｔｏｎＣｏｍｍｕｎｉｃａｔｉｏｎＳｙｓｔｅｍｗｉｔｈＳｔｏｃｈａｓｔｉｃＶａｒｉａｔｉｏｎｏｆＧａｉｎ￥ＷＥＮＹａｎｇｊｉｎｇ；ＣＨＥＮＭｉｎｇｈｕａ；ＺＨＡＮＧＭｉｎｇｄｅ；ＹＡＮＧＸｉａｎｇｌｉｎ（Ｄｅｐａｒｔｍｅｎｔｏｆ...     

拉曼增益对双折射光纤中孤子传输特性的影响

本文采用考虑拉曼增益的耦合非线性薛定谔方程,利用分步傅里叶方法求解并仿真模拟了光孤子脉冲在不同性质的双折射光纤中传输时的演化过程.结果表明,拉曼增益可以有效抑制非线性耦合导致的孤子漂移,同时会导致光孤子脉冲峰值在传输时不断增大,产生拉曼放大效应.拉曼增益也可以有效抑制双折射光纤中传输的相邻光孤子之间的相互作用.     

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.     

拉曼增益对孤子传输特性的影响

利用考虑拉曼增益效应的非线性薛定谔方程, 在忽略光纤损耗的情况下, 采用基于MATLAB的分步傅里叶数值算法, 得出线性算符和非线性算符具体的表达式, 分步作用于光孤子脉冲传输方程, 仿真模拟了光孤子在光纤中传输时的演变. 与不考虑拉曼增益的光孤子在光纤中传输相对比, 探析了拉曼增益对孤子传输特性的影响.拉曼增益会破坏孤子的传输周期, 导致孤子在光纤中传输时快速衰减, 并且影响程度和输入孤子的脉冲峰值功率大小有关, 拉曼增益对基态孤子和高阶孤子的影响也不相同. 关键词： 拉曼增益 孤子 对称分步傅里叶法 非线性薛定谔方程     

色散缓变光纤的非线性啁啾效应

由于光孤子在光纤中传输受到啁啾效应等多种因素的影响 ,使孤子脉宽展宽 ,光脉冲在终端变得不可检测 ,严重影响误码率 ,所以研究不同因素对孤子脉宽的影响有其重要意义。本文求解了色散缓变光纤中含频率非线性啁啾效应的NLS方程 ,由得到的孤子解讨论了非线性啁啾效应和色散缓变效应对孤子脉宽的影响 ,由此说明 ,色散缓减效应等效长距离分布参数光纤放大器的增益 ,它导致非线性效应增加 ,孤子进一步被压缩 ,非线性啁啾效应使孤子在z值较小时 ,其脉宽收缩 ,在z值较大时又使孤子脉宽展宽。     

Dynamics of Spatial Dark Solitons Trapped in the Media with Gain and TPA

The propagation of dark solitons in nonlinear media that include gain and Joss described by a nonlinear Schroedinger equation is investigated. Based on the direct approach of perturbation theorv, the width, height and other related quantities of dark solitons are obtained. It is shown that stationarv propagation of dark solitons is found to be possible in the presence of both gain and absorption. The results obtained by means of our analytic method are in excellent agreement with numerical simulations. Our results are helpful for the research into the optical soliton transmission system.     

偏振模色散影响下飞秒孤子的传输特性研究

以Maxwell电磁场理论为基础，在综合考虑了高阶色散、高阶非线性、自相位调制、交叉相位调制、自变陡、脉冲内喇曼散射及偏振模色散等因素的基础上，推导了飞秒孤子脉冲在双折射光纤中传输的耦合非线性薛定谔方程，并利用分步傅里叶方法对该方程进行了数值计算，研究分析了偏振模色散对飞秒孤子传输的影响。结果发现：当Dp≤0.1ps/km1/2时，偏振模色散对系统的影响很小，随着偏振模色散值的增大，系统的传输性能迅速恶化，当偏振模色散值达到0.3ps/km1/2时，系统的传输距离已经不到无偏振模色散时的1/3；若同时考虑光纤的高阶效应，以飞秒孤子作为载体的系统已经不能实现高速长距离的传输。     

拉曼增益和自陡峭效应对艾里脉冲传输特性的影响

利用包含拉曼增益和自陡峭效应的非线性薛定谔方程, 忽略光纤损耗的情况下, 模拟和分析了艾里脉冲在单模光纤中的传输特性. 发现艾里脉冲在光纤中传输时由于受到拉曼增益和自陡峭效应的影响, 在一定条件下会转变为孤子, 并且, 转变后形成的孤子传播方向发生了偏移. 在时域方面, 艾里脉冲的小峰个数迅速减少, 变成含有一个主峰和次峰能量可以忽略的峰值结构, 此时, 可以把这个峰值结构近似为孤子的结构. 同时发现, 不管截止系数a和艾里函数振幅b 取什么值, 拉曼增益和自陡峭效应都会减小艾里脉冲的时移. 研究了艾里脉冲的加速度特性, 发现一定的传输距离下, 艾里脉冲的横向加速度在初始时并不是一个稳定的值, 但随着传输距离的增大, 加速度慢慢趋于稳定.     

Soliton interaction in birefringent optical fibers: Effects of nonlinear gain devices

This paper presents the influences of polarization mode dispersion (PMD) on the performance of soliton transmission system in birefringent fibers. Dispersive waves generated in single mode fibers due to PMD degrade the soliton transmission system in two aspects. First, solitons continuously lose their energy, thus cause enhancement in pulse width. Second, the dispersive waves interact with neighboring pulses and cause distortion in a sequence of pulses. Both these effects reduce the effective bit-rate and degrade the performance of high-speed optical transmission systems. Optical fibers with large group velocity dispersion (GVD) have less dispersive waves and are relatively robust to pulse broadening, but it enhances the interaction between the adjacent pulses. In this paper, we analyzed these effects of PMD on soliton propagation in birefringent fibers and introduced nonlinear gain devices with perturbation terms proportional to second and fourth power of amplitudes to reduce these effects. We proposed Symmetric Split-Step Fourier Method to solve the coupled nonlinear Schrödinger equations (CNLSE); which yields better results over the existing Split-Step Fourier Method.     

拉曼散射与自陡峭效应对皮秒孤子传输特性的影响

通过求解包含拉曼增益和自陡峭效应的高阶非线性薛定谔方程, 运用MATLAB模拟了拉曼增益和自陡峭效应共同作用对孤子脉冲在各向同性光纤中传输特性的影响, 结果表明, 自陡峭效应会导致孤子产生时域位移, 而且会使高阶孤子产生孤子分裂现象. 与此同时, 拉曼增益改变了孤子的传输特性, 抑制了自陡峭效应, 从而导致脉冲宽度增大、脉冲偏移程度减弱、高阶孤子分裂成基阶孤子所需的传输距离增大.     

Pulse–pulse interaction in dispersion-managed fiber systems with nonlinear amplifiers

The pulse–pulse interaction in a dispersion-managed fiber system is studied for the case when a nonlinear gain and spectral filtering are included into the dispersion-gain map. In this system, the pulse of any shape converges quickly to a dispersion-managed soliton. Using the technique of interaction plane, we have found stable bound states of two pulses. The effects we have studied may significantly reduce the chances of pulse coalescence in specially designed optical transmission lines.