【作者】 马磊；

【导师】 季伟；

【作者基本信息】 山东大学 ， 通信与信息系统， 2015， 硕士

【摘要】 从1966年英籍华人高锟发表的一篇论文开始,在短短的几十年间,光纤通信经历了从无到有、从低速到高速、从单波到合波、从短距到长距的飞跃式发展,而在当今世界的通信领域里,光纤通信几乎无处不在,互联网、电信网、广播电视网等都有着光纤通信的身影,并且它正朝着更快的速率、更大的容量、更远的距离大步迈进。随着光纤通信的不断发展,为了提高光纤传输的速率和保证传输质量,在无线通信领域应用成熟的调制解调技术开始相继出现在光纤通信中。目前,光纤通信最常用的调制技术是幅度调制和相位调制。强度调制在光纤通信的起步阶段应用普遍,但是随着WDM/DWDM网络的出现及发展,相位调制被广泛应用,DPSK、DQPSK等调制方式也相继被应用到了10Gbps、40Gbps甚至是100Gbps的光信号中。本文的主要内容是设计并实现了一种新型的RZ-DPSK解调译码系统,与普通的RZ-DPSK解调系统不同的是,本系统采用了SFP+光模块替代了平衡接收机,并且能够实现信号的精确解调并最终译码输出。首先,本文对DPSK相位调制解调的原理进行了阐述,分析了选取RZ-DPSK作为通用调制方式的原因。然后,介绍了系统的软硬件模块化设计原理、工作流程,并依次对各硬件模块和软件模块进行了描述。随后,重点介绍了基于数字平衡检测的光信号解调算法,该算法弥补了SFP+模块无法返回峰值检测电平的缺点,使得延迟干涉仪的调整能够快速准确。还介绍了基于Berlekamp-Massey迭代的BCH译码算法在FPGA中的实现,因为本系统采用了FPGA芯片为主要的处理计算芯片,该算法实现了实时线速纠错译码功能,满足高速信号的数据吞吐量需求。最后,通过现场实验对系统延迟干涉仪的解调精度、调整时间和解调质量进行了测试和对比,同时也对系统纠错性能进行了现场测试,实验证明了本系统的软件和硬件的稳定性和可靠性都是比较不错的。更多还原

【Abstract】 Since Chinese British Charles Kao published a paper in 1966, optical fiber communication experienced a rapid development from nothing to boom, low-speed to high-speed, single wave to multi-wave, short-distance to long-distance in the short decades. Optical fiber communication is almost everywhere in today’s communication field, like the internet, telecommunication network and broadcasting network and it is marching on to a higher speed, larger capacity and farther distance.As the continuous development of optical fiber communication, in order to improve optical fiber transmission rate and guarantee transmission quality, the modulation and demodulation techniques which matured sufficiently in wireless communications was used in optical fiber communication. At present, the most commonly used modulation techniques in optical fiber communication are amplitude modulation and phase modulation. Intensity modulation was used widely at the beginning of optical fiber communication. However, as the emergence and expansion of WDM/DWDM networks, the phase modulation is applied broadly. Modulation systems like DPSK and DQPSK are applied successively in optical signals of lOGbps, 40Gbps and even 100Gbps.The main content of this paper is to design and realize a new RZ-DPSK demodulation and decoding system. Unlike the usual RZ-DPSK demodulation system, this system uses SEP+ optical module instead of balanced receiver, realizing the accurate signal demodulation and decoder output. Firstly, the paper elaborates the concept of DPSK phase modulation and demodulation, analyzing the reason why RZ-DPSK is chosen as the common modulation system. Secondly, it introduces the system’s software and hardware modular design principle and working process with the description of each hardware and software modular. Thirdly, this paper emphasizes the optical signal demodulation algorithm that based on digital balance detection. The algorithm avoids the disadvantage that the SEP+ module could not return detection peak level which makes the justification of the delay interferometer more rapid and accurate. This paper also introduces the realization of Berlekamp-Massey iteration-based BCH decoding algorithm in FPGA. The system chooses FPGA chip as the main computation processing chip. Therefore, the algorithm realizes the real-time wire-speed error-correcting decoding function which ean satisfy the data throughput of high speed signals. Lastly, the decoding accuracy, justification time and decoding quality of the delay interferometer as well as the error-correcting function are testified and compared through field tests. The tests prove that both the stability and reliability of the system’s software and hardware are excellent.更多还原