光正交频分复用系统传输技术的研究—发端优化技术

发布时间：2018-03-29 16:21

本文选题：光正交频分复用　切入点：发射端　出处：《电子科技大学》2014年硕士论文

【摘要】：随着网络传输容量需求的不断增加,对于光通信网络的传输要求也越来越高,同时数字信号处理技术与集成电路的不断发展使得正交频分复用(OFDM)技术越来越得到人们的关注,将正交频分复用技术引入光通信是近年来的研究热点。光正交频分复用技术结合了正交频分复用和光纤通信技术的优点可以构造出高频谱利用率、大容量、低成本的传输网络。光正交频分复用系统可以分为直接检测光正交频分复用系统(DD-OFDM)与相干检测光正交频分复用系统(CO-OFDM),同时光正交频分复用可以与波分复用技术相结合构造出容量更大的传输系统。由于光正交频分复用系统具有优越的性能使得光正交频分复用系统技术在长途通信、光接入网等应用中具有很大的潜力,但是系统所使用的调制器与发端调制结构直接影响着系统的性能。本论文正是针对上述问题,分析了调制器的调制特性与发端调制结构对系统性能的影响,并依据各个系统应用的场景对其进行结构上的优化。本论文主要内容如下:1.介绍了OFDM技术的基本原理,并归纳总结了常见光OFDM系统的实现方法以及特点。2.研究了DD-OFDM系统中MZM调制非线性的影响和利用光I/Q调制结构优化了基带单边带调制。首先介绍了DD-OFDM系统典型结构并搭建了单边带DD-OFDM仿真平台,其次在此基础上研究了MZM调制非线性对于系统的影响,主要包括偏置点与调制电压选取、不同子载波数、不同调制格式下的系统影响,最后提出了使用光I/Q调制结构代替双驱动调制器以实现单边带DD-OFDM系统。3.研究了CO-OFDM系统中的发射端调制结构与脉冲成形的影响。首先介绍了CO-OFDM系统典型的调制方法;其次提出了使用预失真电路和双驱动调制器来代替传统的光I/Q调制器的方法,经过数学原理推导以及仿真分析对比说明预失真方法具有较好的性能和可用性;最后对通常使用的脉冲成形进行了对比分析得到使用平方根升余弦成形滤波使得系统具有较好的性能。4.对OFDM与WDM结合的系统进行了简单的分析,说明了OFDM技术与WDM技术相结合在长距离大容量光纤通信系统中有应用潜力。
[Abstract]:With the increasing demand of network transmission capacity, the transmission requirements of optical communication networks are becoming more and more high. At the same time, with the development of digital signal processing technology and integrated circuit, OFDM (orthogonal Frequency Division Multiplexing) technology has attracted more and more attention. The introduction of orthogonal frequency division multiplexing technology into optical communication is a hot topic in recent years. Combining the advantages of orthogonal frequency division multiplexing and optical fiber communication technology, optical orthogonal frequency division multiplexing technology can construct high spectral efficiency and large capacity. The optical orthogonal frequency division multiplexing system can be divided into direct detection optical orthogonal frequency division multiplexing system (DD-OFDM) and coherent detection optical orthogonal frequency division multiplexing system CO-OFDM.The optical orthogonal frequency division multiplexing can be combined with wavelength division multiplexing technology. The optical orthogonal frequency division multiplexing (OOFDM) system has excellent performance, which makes the optical orthogonal Frequency-Division Multiplexing (OOFDM) technology in long-distance communication. Optical access network and other applications have great potential, but the modulator and transmitter modulation structure used in the system directly affect the performance of the system. This paper analyzes the modulation characteristics of modulator and the effect of the modulation structure of the transmitter on the system performance, and optimizes its structure according to the application scenes of each system. The main contents of this paper are as follows: 1. The basic principle of OFDM technology is introduced. The realization methods and characteristics of common optical OFDM systems are summarized. Secondly, the influence of nonlinear modulation of MZM in DD-OFDM system is studied and the baseband SSB modulation is optimized by using optical I / Q modulation structure. Firstly, the typical structure of DD-OFDM system is introduced. And the single sideband DD-OFDM simulation platform is built. Secondly, the influence of MZM modulation nonlinearity on the system is studied, including the selection of bias points and modulation voltages, the number of subcarriers and the effects of different modulation formats. Finally, the optical I / Q modulation structure instead of the double drive modulator is proposed to realize the SSB DD-OFDM system. The effects of the transmitter modulation structure and pulse shaping in the CO-OFDM system are studied. The typical modulation methods of the CO-OFDM system are first introduced. Secondly, the method of using predistortion circuit and dual-drive modulator to replace the traditional optical I / Q modulator is put forward. The mathematical principle derivation and simulation analysis show that the predistortion method has good performance and availability. Finally, by comparing and analyzing the pulse shaping used in common use, it is found that using square root raised cosine shaping filter makes the system have better performance. 4. The system combining OFDM and WDM is simply analyzed. The application potential of the combination of OFDM technology and WDM technology in long distance and large capacity optical fiber communication system is explained.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53

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