共查询到19条相似文献,搜索用时 364 毫秒
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建立了一种实时提取一阶和二阶偏振模色散的模型,可以直接得到偏振模色散的大小和方向。通过数值模拟将得到的偏振模色散大小与从琼斯矩阵理论中计算的结果进行比较,我们模拟结果与理论计算值在差分群时延为一个比特周期内较好相符。从得到的偏振模色散矢量的大小和方向信息可以为高阶阶偏振模色散补偿提供前馈信息 相似文献
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提出了一种新偏振模色散(PMD)补偿的方法,直接从被补偿光纤中提取偏振色散矢量的大小和方向信息,根据算法调节偏振模色散补偿器的各参量,使得补偿器的快轴与被补偿光纤的慢轴对准,从而使得偏振模色散得到补偿。这种方法的优点是减少了搜索的自由度。建立了40Gb/s偏振模色散前馈补偿系统,并通过数值模拟.对40Gb/s的非归零(NRZ)码的偏振模色散进行了自适应补偿。通过对补偿前后的眼图、偏振度(DOP)和Q值进行对比和分析,结果表明,这种偏振模色散补偿的前馈方法是非常有效的。 相似文献
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为了说明当光纤通信系统中存在高阶偏振模色散时,采用DOP和电带宽作反馈信号PMD补偿效果均会受到高阶偏振模色散的影响,用数值模拟方法比较了二种常用的反馈控制信号与偏振模色散的性能,模拟结果表明,从性能上讲,二种反馈信号都随一阶PMD变化而具有线性变化,当系统中有高阶偏振模色散时,二者均不具有线性的变化。模拟结果对偏振模色散补偿具有一定的指导意义。 相似文献
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光纤通信线路的偏振模色散已成为高速、长距离光纤通信系统发展的主要障碍之一 ,其特性、测量以及补偿方法的研究成为目前光纤通信研究热点之一。偏振模色散仿真器 ,用于仿真传输链路的偏振模色散特性 ,不仅可用于偏振模色散补偿器 ,也可用于高速长距离光纤通信系统的规划设计等。本文分析了光纤偏振模色散仿真器的研究现状 ,归纳总结了现有偏振模色散仿真器的设计原理和结构特征 ,并用蒙特卡罗法对常用的偏振模色散仿真器的特性进行了数值模拟 相似文献
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偏振模色散模拟器产生二阶PMD的理论研究 总被引:2,自引:2,他引:0
对基于保偏光纤(PMF)级联的偏振模色散模拟器(PMD emulator)产生的二阶PMD进行了数值模拟,结果表明,采用偏振控制器(PC)连接明显优于可旋转连接器(FC)连接,当级联段数N=8时,PC连接的模拟器产生的二阶PMD与理论曲线基本符合;PMF的长度对PMD模拟器模拟二阶PMD并没有明显影响。 相似文献
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Chernyak V. Chertkov M. Gabitov I. Kolokolov I. Lebedev V. 《Lightwave Technology, Journal of》2004,22(4):1155-1168
This paper presents a method that allows evaluating the performance of an optical fiber system where bit errors result from a complex interplay of spontaneous noise generated in optical amplifiers and birefringent disorder of the transmission fiber. We demonstrate that in the presence of temporal fluctuations of birefringence characteristics, the bit-error rate (BER) itself is insufficient for characterizing system performance. Adequate characterization requires introducing the probability distribution function (PDF) of the BER obtained by averaging over many realizations of birefringent disorder. Our theoretical analysis shows that this PDF has an extended tail indicating the importance of anomalously large values of BER. We present the results of comprehensive analysis of the following issues: 1) The dependence of the PDF tail shape on detection details, such as filtering and regular temporal shift adjustment; 2) the changes in the PDF of BER that occur when the first- or higher order polarization mode dispersion (PMD) compensation techniques are applied; 3) an alternative PMD compensation method capable of providing more efficient suppression of extreme outages. 相似文献
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采用琼斯矩阵与随机耦合的波片模型(Monte—Carlo)方法相结合研究了在偏振模色散(PMD)和偏振相关损耗(PDL)共同作用下,超短光脉冲经光纤传输后脉冲被展宽的统计特性。结果表明,通过与偏振模色散的相互作用,偏振相关损耗可以引起光脉冲的压缩效应,同时脉冲展宽和压缩的概率密度分布与光纤偏振模色散及偏振相关损耗的相对数值存在十分密切的关系。在偏振模色散为0.05ps/km^1/2,光纤长度为75km的情况下,当偏振相关损耗均值从0.07dB/km增加到0.49dB/km时,光脉冲被压缩的概率从4.3%增大到92.9%。无论何种情况下,脉冲压缩和展宽的概率密度均可用瑞利-麦克斯韦分布函数进行描述。 相似文献
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Khosravani R. Lima I.T. Jr. Ebrahimi P. Ibragimov E. Willner A.E. Menyuk C.R. 《Photonics Technology Letters, IEEE》2001,13(2):127-129
We investigate both experimentally and theoretically a new technique to realistically emulate polarization-mode dispersion (PMD). We propose and demonstrate a PMD emulator using rotatable connectors between sections of polarization-maintaining fibers that generates an ensemble of high PMD fiber realizations by randomly rotating the connectors. It is shown that: (1) the DGD of this emulator is Maxwellian-distributed over an ensemble of fiber realizations at any fixed optical frequency; and (2) the frequency autocorrelation function of the PMD emulator resembles that in a real fiber when averaged over an ensemble of fiber realizations. A realistic autocorrelation function is required for proper emulation of higher order PMD and indicates the feasibility of using this emulator for wavelength-division-multiplexing (WDM) systems 相似文献
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Comparison of polarization mode dispersion emulators 总被引:10,自引:0,他引:10
Lima I.T. Jr. Khosravani R. Ebrahimi P. Ibragimov E. Menyuk C.R. Willner A.E. 《Lightwave Technology, Journal of》2001,19(12):1872-1881
We analyze polarization mode dispersion (PMD) emulators comprised of a small number of sections of polarization-maintaining fibers with polarization scattering at the beginning of each section. Unlike previously studied devices, these emulators allow the emulation of a whole ensemble of fibers. We derive an analytical expressions and determine two main criteria that characterize the quality of PMD emulation. The experimental results are in good agreement with the theoretical predictions 相似文献
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Corsi F. Galtarossa A. Palmieri L. Schiano M. Tambosso T. 《Photonics Technology Letters, IEEE》1999,11(4):451-453
Experimental results of continuous-wave polarization mode dispersion (PMD) measurements are presented. The proposed technique is based on the backscattered signal given by the Fresnel reflection at the fiber far-end. Experimental statistical distribution of the differential group delay of the round-trip is reported. It presents a Rayleigh distribution whose mean value is simply related to the fiber mean differential group delay. Finally, the statistical distribution of the round-trip dispersion vector is found experimentally and numerically. The proposed method can be easily used for one-end measurement of PMD in installed optical cables 相似文献
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It is known that the differential group delay (DGD) due to polarization mode dispersion (PMD) can be effectively reduced by spinning the fiber during drawing. In this paper, we propose an analytical approach that allows optimization of the spinning design. The fundamental idea is that, in the absence of polarization coupling, an optimized spinning profile can balance the effects of the intrinsic linear birefringence so that the differential group delay can be forced to be periodic and, consequently, have a limited amplitude as a function of distance. Our approach Is independent of the spin profile. In other words, with a fixed set of parameters that characterize a particular spin function, we are able to find analytically the values corresponding to a periodic DGD in a deterministic regime. Numerical results based on waveplate model confirm the analytical prediction and show that PMD can be reduced by about two orders of magnitude with respect to the same fiber without spinning, even after the introduction of random polarization coupling 相似文献
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Hok Yong Pua Peddanarappagari K. Benyuan Zhu Allen C. Demarest K. Rongqing Hui 《Lightwave Technology, Journal of》2000,18(6):832-841
An adaptive polarization-mode dispersion (PMD) compensation system has been developed to cancel the effects of first-order PMD by producing a complementary PMD vector in the receiver. Control parameters for the PMD compensation system comprised of a polarization controller and a PMD emulator are derived from the nonreturn-to-zero (NRZ) signal in the channel to be compensated. Estimates of the link's differential group delay (DGD) and principal states of polarization (PSPs) based on this signal are reliable when the signal power is equally split between the link's two PSP's; however this condition cannot be assumed. To meet this requirement, we scramble the state of polarization (SOP) of the input signal at a rate much greater than the response time of the PMD monitor signal so that each sample represents many different SOP alignments. This approach allows the effective cancellation of the first-order PMD effects within an optical fiber channel 相似文献