基于高非线性光纤四波混频效应的频谱整合技术及其性能的研究

发布时间：2018-06-09 11:39

本文选题：频谱整合 + 高非线性光纤　；参考：《苏州大学》2016年硕士论文

【摘要】：光纤通信自90年代普及以来,随着光纤制备技术以及网络技术的不断发展在通信速率和容量上已取得很大突破。以光纤作为传输媒介的WDM通信网络,是光纤通信领域的重大进步,然而WDM网络固定的频谱分配策略,渐渐难以适应现代多样的网络通信需求,此时,具有灵活频谱分配策略,频谱利用率更高的基于正交频分复用OFDM技术的弹性光网络应运而生。OFDM技术提出子载波概念,子载波之间相互正交,这使得相邻通道之间不需要设立隔离带宽,从而大大提高了频谱使用效率。弹性光网络中,由于业务流量的复杂多变,系统频谱资源被不断的分配释放,由于时间的积累,整个网络中会出现一些空闲的频谱,这些空闲频谱不但造成了频谱资源的浪费,而且提升了网络出现阻塞的概率。因此频谱整合成了弹性光网络研究领域的热点课题,关于解决频谱碎片化问题的方法,目前主要集中于网络算法和系统传输层两个层面。系统传输层频谱整合依赖于光通信领域的一项关键技术-波长转换技术。波长转换技术因其广阔的应用前景,一直备受关注。本课题研究集中于研究频谱整合过程中的波长转换技术。具体内容包括:讨论基于高非线性光纤的波长转换器所存在的一些问题,比如SBS效应限制输入泵浦功率,进行多次波长转换需多级HNLF,系统成本过高等。就基于HNLF的波长转换器的这些缺陷提出优化方案,具体包括:1.使用两级HNLF级联取代原先一级HNLF作为FWM效应的非线性介质,在增加了非线性介质长度的同时,一定程度上抑制了SBS效应;2.考虑到光纤具有双向传输特性,提出使用一级HNLF外加两个环行器的波长转换结构,实现只使用一级HNLF即可完成两次波长转换过程,从节约系统成本的角度来看,这个方案有研究价值。除了提出方案以外,研究过程中我们还对提出的优化方案,通过数字仿真和实验的方式进行了测试验证,得出的结果与预期基本一致。在介绍了关于HNLF波长转换器的优化方案的基础上,将已优化的波长转换器应用于一个具体的频谱整合实例中,经过测试分析,只要通过合理的计算设定波长转换器的泵浦波长等参数,均可实现较为理想的整合效果,频谱碎片可被有效清除,转换信号质量良好。
[Abstract]:Since the popularization of optical fiber communication in 1990s, with the continuous development of optical fiber fabrication technology and network technology, great breakthroughs have been made in the communication rate and capacity. WDM communication network with optical fiber as the transmission medium is an important progress in the field of optical fiber communication. However, the fixed spectrum allocation strategy of WDM network is gradually difficult to adapt to the needs of modern network communication. At this time, there is a flexible spectrum allocation strategy. The elastic optical network based on orthogonal frequency division multiplexing (OFDM) technology, which has higher spectral efficiency, comes into being as the times require. The concept of sub-carriers is proposed in this paper. The sub-carriers are orthogonal to each other, which makes it unnecessary to set up isolation bandwidth between adjacent channels. Thus, the spectral efficiency is greatly improved. In elastic optical networks, due to the complexity of traffic flow, the system spectrum resources are continuously distributed and released. Due to the accumulation of time, there will be some idle spectrum in the whole network. These idle spectrum not only cause a waste of spectrum resources. It also increases the probability of network congestion. As a result, spectrum integration has become a hot topic in the field of elastic optical networks. The methods to solve the problem of spectrum fragmentation are mainly focused on the network algorithm and the system transmission layer at present. The spectral integration of transmission layer depends on wavelength conversion, a key technology in optical communication field. Wavelength conversion technology has attracted much attention because of its broad application prospects. This paper focuses on wavelength conversion technology in the process of spectrum integration. The main contents include: discussing some problems of wavelength converter based on high nonlinear fiber, such as SBS effect limiting input pump power, multistage HNLFs required for multiple wavelength conversion, high system cost and so on. An optimization scheme for these defects of the wavelength converter based on HNLF is proposed, including: 1. The two-stage HNLF cascade is used to replace the original first-order HNLF as the nonlinear medium of FWM effect. The length of the nonlinear medium is increased and the SBS effect is restrained to a certain extent. Considering the bidirectional transmission characteristics of optical fiber, a wavelength conversion structure with one stage HNLF and two circulators is proposed. The process of wavelength conversion can be completed by using only one stage HNLF. From the point of view of saving system cost, This scheme has research value. In addition to the proposed scheme, the proposed optimization scheme is tested and verified by digital simulation and experiment, and the results are basically consistent with the expected results. Based on the introduction of the optimized scheme of HNLF wavelength converter, the optimized wavelength converter is applied to a concrete example of spectrum integration. As long as the pump wavelength and other parameters of the wavelength converter are reasonably calculated, an ideal integration effect can be achieved, the spectrum fragments can be effectively removed and the quality of the conversion signal is good.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.1

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