【作者】 王茹婷；

【导师】 张晓光； 蒋达娅；

【作者基本信息】 北京邮电大学 ， 光学， 2008， 硕士

【摘要】 本论文研究高速光纤通信系统中信号传输受偏振模色散(PMD)限制的情况下,由于PMD导致脉冲展宽,引起码间干扰,将严重影响信号的传输性能。通过使用前向纠错技术(FEC)来进行信道编码,在接收端译码,用适量的冗余比特来达到纠一定数目错误的目的,提高了信号的传输性能。并将FEC技术与单信道PMD补偿技术相结合,进行了数值模拟,和图形仿真,得到了很好的接收效果。另外对一些码型(如占空比为50%的)归零码(RZ)、载波抑制归零码(CSRZ)和不归零码(NRZ)分别进行了比较,获得了较好的方案。本论文的主要工作如下:(?)简明扼要的介绍了FEC技术的背景和各种编码技术的基本概念,详细说明了RS码的背景及算法。(?)回顾和总结了偏振模色散的基本概念、数值计算模型、统计分布情况和补偿方案。(?)在高速光纤通信系统受PMD限制的信道中传输信号时,观察加入FEC技术前后接收端接收到信号的变化,对信道的传输情况进行了仿真,讨论了FEC技术对于提高信号传输有效性的实际效果。通过作图比较了FEC技术对减小信号传输误码率的效果。(?)对占空比为50%的归零码(RZ)、载波抑制归零码(CSRZ)和不归零码(NRZ)的单信道PMD补偿情况进行了数值模拟,并通过眼图,DGD分别图对补偿效果进行了讨论。(?)将FEC技术和补偿技术相结合,通过将DGD与Q值曲线进行比对,讨论了FEC与补偿结合对于提高信道容限的作用,即验证了两种技术相结合对于提高信号传输性能的影响。更多还原

【Abstract】 In high speed and polarization-mode dispersion(PMD) limited fiber optic communication systems,PMD will expanse the pulse , induce high bit error rate(BER) and terribly disturb the transmission property. In this dissertation, forward error correction(FEC) technique is used to combat the performance of PMD.By adding some redundant bits in transmission and decoding at the receiver, the BER will greatly reduced and the transmission property will enhanced a lot. At the same time,the single-channel PMD compensation technique is also added to the system, then a numerical simulation is listed to show the improvement of the transmission effect. In addition, the simulation based on PMD compensation of some formats:such as return zero format (RZ) with 50% duty cycle, carrier suppressed RZ format(CSRZ) and return to zero format(NRZ) in a single-channel system is given,and the greatest scheme can be received.The research works in the dissertation are summarized as follows:The basic concepts of FEC and different coding technique are introduced briefly,while the knowlodge of the RS is mainly discussed.The basic concepts of PMD, their numerical models used as emulation, the distribution of the first- and higher-order PMD and compensation schemes are reviewed and summarized compendiously.In PMD limited systems, the signal received with or without FEC are compared, and the tranmission simulation is given to show the effect of adding FEC to the systems.The simulation based on PMD compensation of some new-style formats such as return zero format (RZ) with 50% duty cycle respectively, carrier suppressed RZ format(CSRZ) and return to zero format(NRZ) in a single-channel system is given.Combine FEC and compensation technique in PMD limited systems to see how the combination can improve the PMD tolerance by see the relationship between the DGD and Q value,then更多还原