【作者】 陈硕；

【导师】 姚敏玉；

【作者基本信息】 清华大学 ， 电子科学与技术， 2004， 硕士

【摘要】 随着光纤通信技术朝着高速率、大容量和长距离传输方向发展,偏振模色散(PMD)已成为限制高速光通信系统的重要因素之一,越来越受到人们的重视。偏振模色散模拟器是用于实验室研究偏振模色散及其补偿技术的重要器件之一。 本文提出了一种利用光纤挤压式偏振控制器构成的 PMD 模拟器的设计方案,它由两个光纤挤压式偏振控制器和两段高双折射光纤组成,通过单片机进行控制。该模拟器可以产生 0~22ps 的群时延差,同时可以产生 0~121ps2 的二阶PMD。本文提出了通过在程序中加入适当的延时控制的方法,消除了压电陶瓷滞回效应对控制精度的影响,并采用软件编程使模拟器的 DGD 符合 Maxwell 分布的规律。 论文在前期研究工作的基础上对光纤挤压式偏振控制器进行了改进,取消了复位单元,使挤压器从五个减为三个,半波电压达到 15V。偏振控制器工作电压从 300V降低为 150V,响应时间达到 10μs 以内,控制速度大于 1000πrad/s。 研制的光纤挤压式 PMD 模拟器已用于 4×10Gb/s PMD补偿的实验,实现了以偏振度作为反馈信号的 40Gb/s RZ 码的 PMD 自适应补偿,并对解复用后的10Gb/s 信号进行了误码测量。误码测量结果表明补偿后的功率代价小于 1dB。在实现一阶 PMD 补偿的同时能改善二阶 PMD 的影响。 论文对光纤 PMD 统计规律也进行了讨论,提出了采用完全随机模型,可使双折射矢量的三个垂直分量具有高度对称性,因此得到的一阶、二阶 PMD 矢量与 PMD 的统计理论完全符合。更多还原

【Abstract】 Optical fiber communication runs to high bit rate, large capacity and longdistance, along with which polarization mode dispersion (PMD) comes to be one ofthe important factors that limit high bit rate optical communications. More and moreattentions are paid to PMD. PMD emulator is one of the important instruments whichis used in laboratory study. A Design of PMD emulator made of polarization controller using fiber squeezersis proposed in this thesis, which consists of two polarization controllers using fibersqueezers and two segments of high birefringence fibers, and is controlled by amicro-controller unit. The emulator can generate DGDs of 0~22ps in company withsecond order PMDs of 0~121ps2. Relevant time-delays are added to the program, sothat the hysteresis effect of piezoelectricity ceramics is eliminated. Software programis adopted, so that DGDs of the emulator accord withMaxwellian distribution. The polarization controller using fiber squeezers is improved under prevenientgroundworks. Restoration units are cancelled, so that the squeezers are decreasedfrom five to three. Half-wave voltage reaches 15V. Working voltage is reduced from300V to 150V. Response time is within 10μs. Controlling speed is faster than1000πrad/s. The manufactured PMD emulator has already applied to the experiment of 4×10Gb/s PMD compensation. Self-adapted PMD comensation of 40Gb/s RZ codesystem is achieved using polarization degree for the feedback signal. Bit error rates ofthe demultiplexed 10Gb/s signal are measured. Measurement results show that powercost is less than 1dB after compensation. Effect of second order PMD is improved atthe same time when fist order PMD is compensated. Satistical laws of PMD are also discussed in this thesis. An entirely stochasticmodel is proposed, which can cause complete symmetry of the three orthogonalcomponents of birefringence vector. Therefore obtained first and second order PMD II<WP=5>vectors completely accord with the statisticaltheory.更多还原