在线放大器为PSA的动态孤子通信系统传输性能受光纤色散参量影响的研究

通过计算机系统仿真研究光纤色散参量对以相敏光放大器(PSA)作为在线放大器的动态孤子系统传输性能的影响。研究结果表明,PSA增益的相敏特性使孤子脉冲主瓣幅度因光纤色散而下降,脉宽展宽,出现旁瓣。光纤色散值越大,经长距离传输后,孤子脉冲主瓣的下降幅度和脉宽展宽程度越显著;且旁瓣脉宽越宽。     

PSA平均光孤子系统传输性能的研究

本采用计算机系统仿真的方法，研究了应用相敏光放大器(PSA)作为在线放大器的采用平均孤子传输方案的光孤子通信系统中，泵浦光与信号光之间的相位漂移、光纤色散对光孤子通信系统传输性能的影响。仿真的结果表明：泵浦光与信号光之间的相位漂移将导致孤子幅度的下降；由于PSA增益的相敏特性，光纤色散导致孤子脉冲主瓣幅度下降，脉宽展宽，出现旁瓣。     

利用光纤环激光器和色散搭配的孤子传输

对不同波长的光脉冲在由正负色散光纤的组成的光纤链中的传输特性进行了数值和实验研究。实验结果和数值分析表明，在相同的初始条件下，短距离传输时，采用平均色散为正常色散的光纤传输要优于孤子传输方式，长距离传输时，采用孤子传输要优于脉冲在平均色散为正常色散的非线性光纤中传输。在正负色散位移的光纤链中的孤子传输，有一最佳波长。     

利用色散缓变管理孤子消除孤子分裂与变形的方法

提出了色散缓变管理孤子概念，研究了孤子在该系统中的传输特性。结果表明，色散缓变光纤使孤子脉宽变短效应能有效地抵消孤子脉冲的展宽，只要恰当选择色散强度值，就能获得脉宽、峰值功率和波形都很稳定的孤子传输。     

PMD对平均光孤子系统传输性能影响的研究

文章采用计算机系统仿真的方法,通过数值求解简化的基本传输方程和非线性薛定谔方程,研究了采用相敏光纤参量放大器(PSA)作为在线放大器时,偏振模色散(PMD)对系统传输性能的影响.系统传输方案采用平均孤子系统.仿真结果表明:当PMD系数增大时,孤子脉冲出现分裂和展宽,幅度出现衰减,从而导致系统的传输性能下降.     

光孤子在分布式光纤放大器中传输特性的研究

光纤放大器用于补偿光信号在光纤中的传输损耗,是全光通信网中的核心器件。建立了光孤子在分布式光纤放大器中传输的物理模型,采用分步傅里叶变换法数值模拟了光孤子的传输放大特性,讨论了增益色散对光孤子形状和频谱的影响。结果表明：在放大器的反常色散区,随着光孤子的放大,会不断地产生啁啾孤子,孤子频谱会加宽并且产生振荡结构。放大介质的增益色散将会使光孤子幅度下降,宽度展宽,频谱窄化。因此,光纤放大器的色散、非线性效应和增益色散均会对光孤子的传输特性产生影响。     

光纤通信加性噪声中孤子传输非线性问题

光纤中具有轻微的非线性和一定的色散特性,这两种特性分开来说,将会损害光纤通信中系统的性能,但是在一定的条件下,这种小的非线性的影响可以抵消色散的影响,产生孤子.在无耗的光纤介质中,孤子可以传输任意距离而不改变形状.实际的有耗光纤中,为了使用孤子,用光放大器来抵消光纤的损耗,以维持链路上孤子能量的稳定.通常在光纤中非线性和色散效应都比较弱,对光纤的作用表现为两种效应的相加性.放大器的自发辐射噪声(ASE),通过两种不同的机理增加了系统的误码率(BER):(1)通常的加性噪声的影响;(2)孤子速度的抖动.第二种效应导致脉冲到达时间的抖动,这就是Gordon-Haus效应.由于光纤存在损耗,光孤子在光纤里的传输过程中,其幅度随传输距离按指数规律衰减,必须对孤子能量进行放大.一种是分布式光放大器方法;另一种是集总式光放大器方法.分布式EDFA使用低浓度的掺铒光纤作为传输介质.集总式放大就是在光纤线路中每隔一段距离L接入一段集总式光纤放大器(目前通常采用EDFA)来补偿孤子能量的损失.本文研究了孤子传输在存在损耗和放大器自发辐射噪声(ASE)时的孤子传输方程及其解.并对孤子传输的控制作了概述.(PD3)     

普通单模光纤中光孤子传输问题的研究

在使用普通单模光纤的光孤子传输系统中,放大器自发辐射（ASE）噪声和色散波逸出是限制光孤子传输的两个主要因素,它们将引起孤子能量科动和定时抖动,从而导致系统误码。本文分别研究了带限光滤波器对ASE噪声的抑制和非线性增益对色散波的抑制以及对孤子传输系统的稳定作用,并设计了使用普通单模光纤的光孤子传输系统。     

色散管理光纤激光器中束缚态孤子动力学演化特性

光孤子脉冲在光纤中传输时由于复杂的非线性相互作用可以形成稳定的孤子束缚态形式,脉冲间的相位关系变化揭示出非线性系统中孤子丰富的动力学特性。通过金兹堡朗道方程描述光孤子在光纤激光器中的传输规律,数值分析了色散管理光纤激光器中系统参量对于束缚态孤子相位突变的影响。研究发现,光纤激光器在相空间中存在多种形式的孤子束缚态,系统的初始状态对于孤子最终状态的演化具有重要的影响。数值分析表明:激光器系统泵浦强度的变化,不仅导致孤子脉冲时间间距的变化,也会导致孤子束缚态的相位差,这对于深入了解光纤中光孤子的动力学过程具有重要的研究意义。     

周期三阶色散对色散管理孤子传输的影响

建立了含有三阶色散的色散管理系统模型,研究了周期三阶色散对色散管理孤子传输的影响.结果表明,三阶色散独立于其它效应,它导致色散管理孤子出现显著的线性延时和轻度崩塌,而且它对色散管理孤子的影响在传输距离上可平均.若周期性地改变光纤的三阶色散系数,可有效避免它对色散管理孤子传输的影响.     

The maximum bit rates of soliton communication systems with lumpedamplifiers and filters in different distances

The maximum bit rate of a soliton communication system with lumped amplifiers and optical filters is considered. When the dispersion of the fiber varies from one amplifier spacing to another amplifier spacing, the maximum bit rate is significantly reduced. To overcome the effect, the amplitude of the soliton is amplified so that it is still the average soliton corresponding to the fiber dispersion for an amplifier spacing. Thus, the maximum bit rate is only slightly less than that without the dispersion variations. For a given distance, the maximum bit rate limited by the stability and soliton interaction is obtained. The result is compared with that limited by the Gordon-Haus effect. For shorter transmission distance, the maximum bit rate is limited by the stability and soliton interaction. For longer transmission distance, the maximum bit rate is limited by the Gordon-Haus effect     

色散控制WDM孤子通信系统中的定时抖动

采用拉格朗日变分法在同时考虑本信道放大自发辐射 (ASE)噪声、相邻信道信号对本信道信号和ASE噪声等多种因素影响的情况下 ,分析了色散控制孤子的传输演化特性 ,给出了准稳态色散控制孤子传输动力学方程和定时抖动解析表达 ,并给出了三种扰动因素影响程度的比较。     

The Choice of Dispersion Managed Schemes in Standard Single-Mode Fiber

In this paper, the three allocated schemes of dispersion-managed soliton are proposed on standard single-mode fiber. Adopting variational method and on the proposed schemes, the timing jitter introduced from the perturbations of amplifier spontaneous-emission (ASE) and cross-phase modulation in wavelength-division multiplexing is studied. Compared with performances of different system schemes, the principles of optimal allocated dispersion management are obtained, which can be used to optimal allocated dispersion managed soliton system.     

Characteristics of Power Enhancement in Dispersion-Managed Soliton Systems

The range of applicable power enhancement factors in dispersion-managed soliton systems is investigated. For a dispersion compensation period equal to one amplifier span, it is found that the applicable power enhancement factors are not very sensitive to the dispersion perturbation. A power enhancement factor of about 2 is found to be almost optimal. However, the optimal power enhancement factor can be increased by using a compensation period covering several amplifier spans. In this case, the optimal power enhancement factor increases with the increasing dispersion perturbation.     

Nonlinear Gain Control of Dispersion-Managed Soliton Amplitude and Collisions

The stabilizing action of nonlinear gain on dispersion-managed soliton transmissions is investigated. By means of a proper combination of nonlinear gain and filtering, the background and amplitude instability introduced by lumped guiding filters can be controlled. Indeed, radiative background that may not be separated from the signal when the average dispersion is close to zero is shown to be suppressed. Taking advantage of the large tolerance with respect to input energy variations, dispersion-managed solitons are found to be stable after collisions among different frequencies when supported by the same nonlinear gain element for all channels. This demonstrates the feasibility of nonlinear gain for wavelength-division-multiplexed transmissions and may open up the possibility of high-speed soliton transmission with large tolerance with respect to power fluctuations and densely packed wavelength channels.     

Experimental quantification of soliton robustness to polarizationmode dispersion in conventional and dispersion-managed systems

We have experimentally quantified the soliton robustness to polarization mode dispersion (PMD) in both conventional and dispersion-managed (DM) soliton systems. Long-term measurements were performed in a computer-controlled system where the PMD characteristics varied randomly with time. Apart from the PMD itself, the performance of both systems depends on the average dispersion while the performance of the DM system also depends on the dispersion map strength. The results show that the robustness can be even more pronounced for DM systems with relatively small dispersion map strengths (0相似文献   

用行波解法研究集总放大光纤孤子系统的稳定性问题

本文采用行波解法求解了集总放大光纤孤子系统脉宽为皮秒量级含放大器增益的非线性薛定谔方程，得到了近似形式的解析解，并得到了孤子振幅、中心位置、相位的演化方程，在此基础上统一地研究了孤子传输的稳定性问题，得到了在集总放大光纤孤子系统中孤子能稳定传输的结论。     

Energy enhancement of dispersion-managed solitons in optical fibertransmission systems with lumped amplifiers

We simulated dispersion-managed soliton propagation in optical fiber transmission systems with lumped amplifiers and loss. The energy enhancement of dispersion-managed solitons can be more or less than in the lossless case, depending delicately on the amplifiers arrangement. In all cases, there is a maximum enhancement factor beyond which the dispersion-managed soliton no longer exists and which also depends delicately on the arrangement     

色散管理孤子系统定时抖动的分析计算

利用两种方法研究了脉冲形状为高斯型的色散管理孤子系统定时抖动。利用微扰变分方法推导出光通信系统存在滤波器和自发辐射噪声的情况下,孤子参数演化的动力学方程,得出了定时抖动的表达式,并对其进行仿真,发现定时抖动来源于放大器噪声、频率偏移等,啁啾的符号和滤波器对系统总的定时抖动也有一定影响。再利用矩方法对色散管理孤子系统定时抖动进行了分析,两种方法得到的结果一致。