基于叠印采样光栅的光码分多址编解码技术研究

发布时间：2018-04-19 08:56

本文选题：光码分多址 + 光纤光栅　；参考：《南京大学》2014年硕士论文

【摘要】：与目前已成熟的通信技术如波分复用技术相比,光码分多址技术具有抗干扰、内在安全性、成本低、异步接入等许多方面的优势,对于将来的光网络物理层安全和全光高速接入网领域的应用前景十分理想。光码分多址系统的核心器件是编解码器,它承担了对多路信号进行编码共享带宽以及在耦合的信号中挑选出用户需要的信号的重要功能。编码器的性能会对系统性能造成根本性的影响。在众多编码器的候选材料中,光纤光栅以它对光信号强大而灵活的处理能力以及成本上的优势脱颖而出,大大增强了编码器的实用性。目前光码分多址技术不断向实用化方向发展,制作工艺也是限制它实用化的重要因素。在已经成熟的器件工艺基础上来寻找实现编解码器的方案,显然是加快其走向实用化的选择。本文立足于目前发展中遇到的主要问题,对基于光纤光栅的编解码器进行了探究,提出了一系列优化方案。本文首先对光码分多址技术的优点进行了探讨,介绍了光纤通信特别是光码分多址技术的发展现状和研究动态。探讨了光码分多址的系统结构,分析了各种典型的编解码方案及各自优势和不足。随后本文从光纤光栅的原理和分析计算模型出发,总结并探讨了光纤光栅对光信号的处理功能,光纤光栅以其强大而灵活的功能成为编解码器的理想材料。探讨了光纤光栅的主要制作技术以及制作平台的搭建。分析了光纤光栅在编解码器中的典型应用,提出了其在传统应用中的缺点。为了解决传统光纤光栅在对制作上艺精度的严苛要求以及制作过程的复杂程度,本文提出了叠印采样光栅技术。根据等效啁啾和等效相位的原理,叠印采样光栅可以达到和传统光栅一样的编解码功能,但通过分析其特性发现,与传统光栅相比,制作更简单,且成本更低,仅需要-块相位掩模板以及精度为亚微米级的操作平台,即可制作出多个反射波长,结构更紧凑的,可以满足各种类型编解码器的光纤光栅。本文从理论上探讨了基于叠印采样光栅的编解码器的可行性,设计出适用于频谱幅度编解码方案的光纤光栅,并进行了4用户,传输速率为5Gb.s的系统仿真,结果证实了叠印采样光栅在频谱幅度系统的适用性。针对传统多波长编码系统最普遍的问题—-色散进行了对系统优化的探讨,根据等效啁啾的原理,提出了集成完全色散补偿功能的编解码技术,成功设计了适用于频谱幅度系统的叠印采样光栅,并完成了4用户、传输速率为5Gb.s,传输距离为lOkm的系统仿真。在没有任何额外的色散补偿器件的情况下,我们设计的编解码器解码出的光信号无失真情况,没有任何色散残留,得到了信号质量与传统背靠背一致,色散这个不利因素得到了很好的解决。
[Abstract]:Compared with the current mature communication technology such as wavelength division multiplexing (WDM), optical code division multiple access (OCDMA) has the advantages of anti-interference, inherent security, low cost, asynchronous access and so on.It is very ideal for the future physical layer security of optical network and the application prospect of all optical high-speed access network.The core device of optical code division multiple access (OCDMA) system is the codec, which plays an important role in encoding and sharing bandwidth of multi-channel signals and selecting the signals needed by users in the coupled signals.The performance of the encoder will have a fundamental impact on the performance of the system.Among the candidates for encoder, fiber Bragg grating (FBG) stands out because of its powerful and flexible processing power and cost advantages to optical signal, which greatly enhances the practicability of encoder.At present, optical code division multiple access (OCDMA) technology is developing to the practical direction, and the fabrication technology is also an important factor limiting its practicality.On the basis of the mature device technology, it is obviously the choice to speed up the application of the codec.In this paper, based on the main problems encountered in the development of fiber Bragg grating-based encoder and decoder, a series of optimization schemes are proposed.In this paper, the advantages of optical code division multiple access (OCDMA) technology are discussed, and the development and research trends of optical fiber communication, especially optical code division multiple access (OCDMA) technology are introduced.The system structure of optical code division multiple access (OCDMA) is discussed, and various typical coding and decoding schemes are analyzed as well as their respective advantages and disadvantages.Then, based on the principle of fiber grating and the analysis and calculation model, this paper summarizes and discusses the processing function of optical signal by fiber grating. Fiber grating is the ideal material for encoder and decoder with its powerful and flexible function.The main fabrication technology of fiber grating and the construction of fabrication platform are discussed.The typical applications of fiber Bragg gratings in codec are analyzed, and their shortcomings in traditional applications are presented.In order to solve the strict requirements of the traditional fiber grating on the fabrication accuracy and the complexity of the fabrication process, the overprint sampling grating technology is proposed in this paper.According to the principle of equivalent chirp and equivalent phase, the overprinted sampling grating can achieve the same coding and decoding function as the traditional grating, but by analyzing its characteristics, it is found that compared with the traditional grating, the fabrication is simpler and the cost is lower.Only a block phase mask and an operating platform with sub-micron precision can be used to produce multiple reflection wavelengths, which are more compact and can satisfy various types of encoder and decoder fiber Bragg gratings.In this paper, the feasibility of the codec based on overprinted sampling grating is discussed theoretically, and a fiber grating suitable for spectrum amplitude coding and decoding scheme is designed, and the system simulation of 4 users with transmission rate of 5Gb.s is carried out.The results confirm the applicability of the overprinted sampling grating in the spectrum amplitude system.Aiming at the most common problem of traditional multi-wavelength coding system-dispersion, the optimization of the system is discussed. According to the principle of equivalent chirp, a coding and decoding technique integrating the function of complete dispersion compensation is proposed.The overprint sampling grating suitable for spectrum amplitude system is designed successfully, and the system simulation of 4 users with transmission rate of 5Gb. S and transmission distance of lOkm is completed.In the absence of any additional dispersion compensation devices, our designed codec decodes the optical signal without distortion, without any dispersion residue, and the quality of the signal is consistent with the traditional back-to-back.The disadvantage of dispersion is well solved.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1

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