少模模式复用系统与模式耦合效应的研究

发布时间：2018-02-08 17:31

本文关键词： 光纤通信少模光纤模式复用模式耦合模间色散　出处：《北京邮电大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,随着骨干光纤传输系统中通信技术的不断演进以及宽带网络中高速大容量数据业务的井喷式增长,全球通信系统对于传输容量的需求每年都在呈指数形式增长。然而,近期的研究结果表明,由于单模光纤非线性效应的影响以及高速光传输系统中对信号传输光信噪比的要求,利用波分复用技术的单模光纤的传输容量正在快速接近其香农极限,因此必须考虑采用新的复用技术来突破现有的技术瓶颈,增加频谱效率,满足日益增长的网络需求。基于少模光纤的模式复用技术作为一种新兴的光多输入多输出传输方案就是在这种大的背景下发展而来,利用的是少模光纤中的限定模式分别承载信号,实现光纤传输容量成正比例的提成,成为了未来高速大容量光传输系统的关键技术之一。在模式复用系统中,由于工作环境不理想导致的传输光纤的折射率扰动可引起不同光纤模式间的耦合,并导致传输光场的场强与相位分布发生随机变化以及不同信息光路的色散时延。此外模式复用系统中仍存在诸多重要的理论和技术问题有待研究解决,例如模式复用关键器件的实现,模式耦合及色散效应的抑制,不同串扰情况下的少模光纤构造设计等。本文就是通过重点研究模式复用中的随机模间耦合和传输模式特性进行的少模模式复用技术的前沿研究。本文从基本理论出发,重点研究了新型少模光纤在模式复用系统中的应用特性,通过推导麦克斯韦方程组分析了少模光纤中作为复用技术基础的信息承载模式的相关特性,并在特定弱导少模光纤条件下,提出了可描述模式耦合以及模间色散的参数化物理模型,仿真分析了利用基模LP01与高阶模式LP11作为模式复用承载信道的可能性与优越性。同时,从波导光学的传输特性出发,设计了一种具有相反色散斜率的多阶跃折射率的少模光纤,作为模式复用系统的传输介质,组成了具有实时补偿色散影响的四跨段传输链路,通过直接探测的模式复用系统仿真分析验证了采用此种方案对传输容量为3*10Gb/s的模式复用系统在传输距离达20.4km的情况下,可有效将传输末端的色散总值控制在111ps以下,并研究分析了模式耦合以及模间色散对系统高性能的综合影响。论文的具体工作安排如下：首先,研究了少模光纤的基本特性,从麦克斯韦方程组出发,详细推导了少模光纤中的光传输特性,分析不同模式的光场场强分布,以及决定光纤中传输模式特性的结构重要参数,并研究模式复用技术的理论基础。其次,从耦合模理论出发,得到不同模式在特定结构下需要满足的耦合模方程,采用光纤分段以及轴向偏移的结构来模拟的少模光纤的由于制作环境缺陷以及光纤微弯带来的模式耦合以及模间色散效应,结合矩阵传输理论建立少模光纤的场耦合模型。为后续构建少模模式复用系统提供了理论模型。再次,对少模光纤模式复用系统的基本模型进行分析探讨,研究模式复用系统中需要解决的关键技术以及构成系统所需的关键问题,详细比对分析不同的优缺点,重点介绍少模光纤设计技术,并提出设计了一种适用于模式复用系统的可具有相反色散斜率的少模光纤,使其作为模式复用系统的传输介质的同时能够实时补偿传输过程中累积的色散影响。最后,采用可具有相反色散斜率的少模光纤段,组成传输距离达20.5km四跨段的传输链路,建立结合模式耦合及模间色散的参数化物理仿真模型,并构建直接探测的模式复用系统,仿真分析其系统传输性能。
[Abstract]:In recent years, with the blowout of high speed and large capacity data communication business evolving technology backbone optical transmission systems and broadband network growth, global demand for transmission capacity of the communication system in every year grows exponentially. However, recent research shows that due to the effect of single-mode fiber nonlinear effect and high speed optical transmission the system on signal transmission in the optical signal-to-noise ratio, the transmission capacity of single mode fiber by using wavelength division multiplexing technology is fast approaching the Shannon limit, so we must consider the reuse of new technology to break the bottleneck of existing technologies, increase the spectrum efficiency, meet the growing demand of network. And the mode division multiplexing mode fiber is a new kind of optical multiple input multiple output transmission scheme is developed in this context is based on the use of few mode fiber in the limit mode Are bearing signals, realize the optical fiber transmission capacity is proportional to the Commission, has become one of the key technologies for future high-speed large capacity optical transmission system. The mode multiplexing system, the work environment is not ideal due to the disturbance rate caused by optical fiber can cause different refractive coupling between optical fiber mode, and lead to the transmission of the light field intensity with the change of phase distribution and different information optical dispersion delay. In addition mode multiplexing system there are still many important theoretical and technical problems to be solved, such as the key device to realize mode multiplexing, suppression of mode coupling and dispersion effect, different crosstalk under the condition of few mode fiber structure design research. Less mode multiplexing technology this paper is focused on by the random mode coupling and mode multiplexing transmission mode characteristics.
From the basic theory, focuses on the application of new characteristics of few mode fiber in mode division multiplexing system, related characteristics as the basis of multiplexing information bearing mode in few mode fiber are analyzed by deriving the Maxwell equations, and in particular the weakly guiding few mode fiber under the conditions proposed can describe the mode coupling and mode the dispersion between the parametric physical model, simulation analysis as a model and the superiority of channel multiplexing bearing the possibility of using the base model LP01 and high-order LP11 model. At the same time, starting from the transmission characteristics of optical waveguide, a design with opposite dispersion slope multi step index few mode fiber as the transmission medium, mode multiplexing system, composed of four segment transmission links with real-time influence of dispersion compensation, through the analysis of the direct detection of the mode multiplexing system is verified by simulation using this scheme for transmission The capacity of 3*10Gb/s in mode division multiplexing system transmission distance of 20.4km, which can effectively control the transmission end of the dispersion value below 111ps, and analyzed the influence of mode coupling and integrated mode dispersion of high performance system. The specific arrangement of the thesis are as follows:
Firstly, study the basic characteristics of few mode fiber, starting from the Maxwell equations, deduced the optical transmission characteristics of few mode fiber in the analysis of the optical field intensity distribution of different modes, as well as an important parameter to decide the structure characteristics of the optical fiber transmission mode, and mode of complex theoretical foundation for technology.
Secondly, based on the coupled mode theory, different models need to satisfy the coupled mode equations in specific structure, the fiber section and the axial offset structure to simulate the production environment because of few mode fiber defects and micro bending optical fiber mode coupling and mode brings color dispersion effect, combined with the transfer matrix theory to establish coupling model less mode fiber. Provides a theoretical model of few mode multiplexing system for subsequent construction.
Again, the analysis of the basic model of few mode fiber mode multiplexing system, key research needs to solve the key technical problems in the system and mode multiplexing system required, with comparison and analysis of different advantages and disadvantages, focuses on the few mode fiber design technology, and design a suitable mode multiplexing system can in contrast with the dispersion slope of few mode fiber, the dispersion effect as the transmission medium mode multiplexing system to the accumulation process of real-time compensation in the transmission.
Finally, using few mode fiber segments with opposite dispersion slope of the transmission link consists of transmission distance up to 20.5km cross section, a combination of parameterized physical simulation model of mode coupling and mode dispersion, and construct the mode multiplexing system of direct detection, simulation analysis of the transmission performance of the system.

【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.11

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