DWDM系统中色散对受激喇曼散射的影响

研究了光纤色散对波分复用(WDM)系统中受激喇曼散射(SRS)非线性效应的影响.提出了一种简便且物理意义明确的分析计算模型,它适合于任意输入信号、任意信道数,以及不同的色散参量.基于该模型,深入分析了两信道光纤通信系统中,各种色散参量下,色散对SRS的影响,得出了色散能减小SRS效应所引起的输出功率的波动的结论,并且给出了在不同色散参量下,输出功率标准差随距离变化的曲线.     

DWDM系统中色散走离条件下SRS效应的统计特性及仿真

文章在"时域分步法"存在衰减、色散限制和受激喇曼散射(SRS)效应作用条件下的N信道SRS效应计算模型基础之上,分别从理论和数值上分析了SRS效应影响下信号输出功率的统计规律,并使用Matlab软件进行仿真,通过比较理论公式仿真与数值仿真的一致性,对于进一步研究SRS效应对系统造成的误码率以及衡量DWDM系统中SRS效应对通信质量的影响有着重要的意义.     

光通信系统中色散容限的分析

文章通过非线性薛定谔方程和主偏振态(PSP)模型.对单模光纤中色散引起的脉冲展宽进行了研究.通过详细计算,对光通信系统中的色度色散和偏振模色散(PMD)做出了合理的估计,并分析了色散容限对系统传输的影响.这些分析对实际系统设计具有一定参考意义.     

DWDM系统中受激拉曼效应的数值解

文章提出一种新的数值计算分析法,运用该计算方法得到了密集波分复用(DWDM)系统在衰减、色散走离和受激拉曼散射(SRS)效应耦合条件下的输出信号功率的数值解.并使用 MATLAB 软件进行了数值模拟仿真,通过数值计算绘出了在短距离传输条件下,不同输入光功率以及不同信道数时SRS效应对光通信系统性能的影响图.     

DWDM光纤通信系统中受激喇曼散射的统计特性

随着通信容量的增大,密集波分复用(DWDM)光纤通信系统中的受激喇曼散射(SRS)非线性效应成为影响系统质量的重要因素.采用时域分步法模型,对色散下的SRS统计特性进行了深入研究,得到了在整码元色散走离时,DWDM系统各信道传输功率的统计特性,推导了各信道传输功率的数学期望、标准差,证实了各信道传输功率符合高斯分布,计算了概率密度函数,并且与仿真数据取得了较好的一致.

Abstract：

With the enlargement of communication capacity, the performance of dense wavelength division multiplexed (DWDM) fiber communication systems might be degraded by nonlinear effect of stimulated Raman scattering (SRS) in the optical fiber. To resolve these problems, the time-domain split-step method is applied to investigate the statistical characteristics of SRS. The mean and the standard deviation of transmission powers of all channels are derived analytically in a closed-form formula for DWDM systems with SRS and integer bits dispersion walk-off. The probability density function (PDF) of output powers of all channels is confirmed to be Gaussian distribution. The numerical results show a good correspondence with analytical formulae.     

偏振模色散和时延抖动对啁啾光纤光栅色散补偿特性的影响

对存在偏振模色散(PMD)和群时延(GD)抖动的非理想线性啁啾光纤光栅的色散补偿特性进行了研究。实验测量了啁啾光纤光栅的群时延谱和偏振模色散光谱，理论分析和实验测量表明，啁啾光纤光栅差分群时延(DGD)抖动与其时延抖动密切相关。通过数值模拟方法，计算了线性啁啾光纤光栅偏振模色散眼图代价与入射到啁啾光纤光栅色散补偿器的光信号的偏振方向的关系，计算结果表明在使用啁啾光纤光栅色散补偿器时应对光信号的偏振方向进行调整，以获得最佳补偿效果。另外结合实验数据，模拟计算并讨论了非理想线性啁啾光纤光栅群时延抖动和偏振模色散引起的信号的展宽和脉冲形状的劣化。     

光传输系统中色散补偿问题的探讨

文章通过对光纤色散的产生及其对传输系统影响的介绍,引出了色散补偿技术.在多种色散补偿方法中,侧重探讨了应用比较普遍的色散补偿光纤(DCF)技术,并在此基础上,联系实际工程,具体阐述了光纤色散补偿模块大小在工程中如何计算、如何配备、如何放置等,获得了一些对实际色散补偿系统有参考价值的结论.     

基于直接控制光纤长度的RoF系统色散管理

基于色散引起的双边带调制信号周期性功率衰落,提出了一种直接控制光纤长度来避免光纤色度色散对接收信号功率影响的新方法.从理论上证明了这个方法的可行性,并通过仿真分析比较了四种色散管理的方法,仿真结果表明,与其他三种方法相比,提出的直接控制光纤长度的方法不仅改善效果显著而且对光源中心频率和调制频率波动并不敏感,是解决WDM...     

SRS效应对DWDM光通信系统质量影响的分析

文章基于在时域分步法存在衰减、色散走离和受激Raman散射(SRS)效应作用条件下的N信道SRS效应计算模型,使用MATLAB软件进行仿真,通过数据仿真分析了SRS耦合效应对密集波分复用(DWDM)光通信系统质量造成的影响以及输入功率、信道数与SRS耦合效应的关系,对进一步研究SRS效应对DWDM光通信系统性能的影响有着十分重要的意义.     

连续波宽带大功率行波管中的色散成型及谐波抑止技术研究

本文对实现宽带互作用的机理及谐波的抑制方法进行了分析研究,得到超宽带行波管对慢波线路色散特性的特殊要求,并对实现这种色散(色散成型)的方法进行了理论与实验研究.以此为基础,研制出一只宽带大功率行波管,在6.5～18GHz频带内,输出功率带边为180W,中频段250W,增益大于35dB.     

DWDM中色散条件下基于两种模型SRS效应的功率转移研究

在DWDM系统中受激喇曼散射（SRS）效应是一种重要的非线性效应。将巩稼民的无色散条件下N信道的SRS效应模型和Singh_Hudiara模型分别加入色散走离,采用＂时域分步法＂对多信道、长距离传输中的＂色散＂以及SRS效应所带来的影响进行仿真。通过对这两种模型的功率转移仿真图对比,得出信号功率的变化随着信道波长的增加而线性增长的结论。这对SRS研究有着重要的意义。     

Waveform distortion due to stimulated Raman scattering in wide-bandWDM transmission systems

The influence of stimulated Raman scattering (SRS) taking into account the random modulation and the walk-off effect on wide-band wavelength division multiplexing (WDM) transmission systems are studied theoretically. First, it is shown that power depletion due to SRS can be separated into average power loss and waveform distortion. The waveform distortion is evaluated for various types of pulse shapes and fibers, and simple equations for evaluating the waveform distortion due to SRS are derived. These equations can be easily applied for designing wide-band WDM transmission systems from the viewpoint of the SRS waveform distortion. We also compare results obtained from our method with those from the split-step Fourier method, and confirm validity of our method. Our method should be useful in the design of wide-band WDM transmission systems, in which SRS is expected to be a serious limitation     

A computer model of non-dispersion-limited stimulated Ramanscattering in optical fiber multiple-channel communications

The development of a computer model for non-dispersion-limited stimulated Raman scattering (SRS) in optical fiber multiple-channel communication systems is reported. The model takes into account the pump depletion due to SRS and the different attenuation coefficients at different wavelengths of operation. It can calculate the SRS effects in any fiber, provided the Raman gain profile for that fiber is known. Thus, the model is general in nature and can be used for a number of problems. It can be used to calculate the output power of all the channels, given the input of every channel and its operating wavelength. It can also be used, at least in principle, to determine the input power level if a desired level of output power is required. Moreover, it can be used to estimate the optical amplification of a signal due to SRS. This is possible because the governing equations for all of these processes are similar and therefore can be solved using the same approach     

Modeling Interchannel FWM With Walk-Off in RZ-DPSK Single Span Links

An analytic model for interchannel four-wave mixing (FWM) is developed for return to zero differential phase shift keying (RZ-DPSK) single span transmission including interchannel walk-off for degenerate FWM (D-FWM) and nondegenerate FWM (ND-FWM). The model is verified by simulations and reasonable agreement is obtained for a 10-Gb/s single span link. Results are presented for different channel spacing, launch pulse duty-cycle, and launch power. The model is strictly valid for systems with low fiber dispersion as it ignores dispersion related pump pulse distortion. It is found that the walk-off effect makes a significant contribution to the detected unfiltered FWM noise and this contribution is mostly concentrated at high frequencies determined by the channel spacing alone. The contribution of the walk-off and its frequency content is understood in terms of intracollision and intercollision interference. In the typical situation when a sub-bit-rate electrical low-pass filter is used, the walk-off effect is effectively removed for all types of FWM. The analytic model is validated by comparing to split-step-Fourier (SSF) simulations. Extension to the general case of multiple FWM lines is considered. It is found that the FWM noise standard deviation is 2 times smaller for RZ-DPSK as compared to that for return to zero on-off keying (RZ-OOK) at the same average launch power for a system with 25-GHz channel spacing.      

光参量放大脉冲发生器中色散效应的研究

走离效应对参量放大脉冲发生器具有重大影响,群速度色散将使脉冲展宽。采用分步傅里叶法对耦合方程求解,分析了利用参量放大器产生脉冲的过程中色散效应的影响。依照所设定参数的仿真结果表明：输入泵浦波的调制频率为1GHz时,走离效应、群速度色散的影响几乎可以忽略;调制频率增加到20GHz,光纤中的群速度色散可以缓解由于泵浦波、闲频波之间的走离效应导致的脉冲畸变;而随着调制频率的继续增大到100GHz,色散效应和走离效应将使得产生的脉冲受到严重恶化。     

NOLM全光解复用中信号转换的数值模拟

为了研究非线性光学环形镜解复用输出特性,采用双曲正割形控制脉冲和信号脉冲,对基于非线性光学环形镜全光解复用系统中信号的转换进行了理论分析,得到了脉冲峰值开关效率为100%时,所需最小初始时钟脉冲峰值功率应满足的条件,数值模拟了走离时间、初始时间延迟和初始时钟脉冲峰值功率对转换信号波形特性的影响。结果表明,走离效应是导致转换信号波形失真以及峰值功率下降的重要因素,初始时间延迟可以平衡由走离效应引起的转换信号波形不对称,初始时钟脉冲峰值功率可以补偿由走离效应导致的转换信号峰值功率下降。     

Theory of the synchronously pumped fiber Raman laser

Analyses of the synchronously pumped fiber Raman laser are presented under the parabolic approximation for gain shaping in both frequency and time domains. A master equation for the Stokes pulse consists of the group velocity dispersion of the fiber, the gain dispersion of the stimulated Raman scattering, a gain-shaping term due to the pump curvature, small depletion, and a walk-off effect. The pump power dependences of the Stokes power and the pulse width and the threshold condition are revealed. The frequency tunability of the present laser is also discussed. It is shown that the oscillation wavelength (carrier frequency of the Stokes pulse) will change linearly with Stokes power because of walk off during depletion.