光纤中受激布里渊散射快光提前及脉冲形变的研究

发布时间：2018-03-14 14:23

本文选题：高非线性光纤　切入点：受激布里渊散射　出处：《兰州理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：在光通信技术高速发展,对信息的转换和接收能力需求进一步提升的时代背景下,全光网络通信势必取代现有的网络通信系统。全光网络通信技术采用光-光直接转换,具有更高效的转换效率、更大的传输容量(大约几十Tb/s),其潜在的应用价值备受人们期待。快慢光技术具有调控光速的能力,可以被用来解决全光通信网络中面临的对信号光的同步和缓存的难题,实现光交换和光路由,解决全光网络通信过程中面临的关键性难题。对于不同的快慢光系统,光纤中快慢光技术是近年来的研究热点。而光纤中基于受激布里渊散射(SBS,Stimulated Brillouin scatting)效应实现快慢光具有极低的泵浦光阈值功率、可以室温下操作、工作波长可调以及与光纤通信系统兼容性良好等优点,更是光速可调技术中的研究热点。本论文以布里渊散射产生快光为研究对象,围绕提高时间提前量、减少脉冲失真分别对光纤中窄带宽泵浦光和宽带宽泵浦光SBS快光特性进行了讨论研究,主要内容如下:1.介绍对比了实现快慢光的各种调控技术,主要论述了近年来国内外基于受激布里渊散射增加快光提前、减小脉冲失真、使用特种光纤提高提前效率的研究现状和应用前景。2.给出了光纤中布里渊散射过程的物理模型和数学推倒过程;考虑到光纤中产生快慢光条件的不同,完善了受激布里渊散射声波-光波耦合方程组;以单色泵浦光为例,从受激布里渊散射耦合方程出发,研究了SBS快光的小信号模型解析解,分别得出了快光的时间提前量和脉冲压缩因子。3.基于受激布里渊散射三波耦合方程组,应用小信号分析,研究了高非线性光纤的信号光脉冲提前及形变。结果表明光纤中信号光脉冲时间提前量在一定范围内随着输入信号光功率和传输距离的增长而近似线性增长,同时脉冲压缩程度加强;相同条件下非线性光纤比普通单模光纤的时间提前量更大,在50m长高非线性光纤中信号光能量在50mw时实现了203ns的时间提前量和较小的脉冲形变。高非线性光纤的快光提前效率显著提高,脉冲形变显著减小,研究结果对快光的实现和应用具有参考意义。4.提出使用具有多条谱线结构的泵浦光实现布里渊宽带快光的方法,分析了多条谱线对应的宽带泵浦下的布里渊吸收特性和相应的相位变化情况,得出通过等振幅谱线叠加可以得到宽带吸收谱,吸收谱宽度随着谱线数目的增加而增加,并且谱线间距对吸收谱底部线性度影响严重。还介绍了宽带宽SBS理论,分别讨论了高斯谱宽带泵浦光和矩形谱平顶泵浦光的布里渊光提前特性,结果表明高斯谱宽带泵浦光和矩形谱平顶泵浦光实现快光可以减小脉冲畸变,较大程度保持原脉冲波形传输。同时,相同情况下矩形谱平顶泵浦光在实现快光过程中脉冲畸变程度更小,相比于高斯谱泵浦光更具优势。
[Abstract]:With the rapid development of optical communication technology and the further improvement of information conversion and reception ability, all-optical network communication is bound to replace the existing network communication system. With more efficient conversion efficiency, larger transmission capacity (about tens of TB / s), its potential applications are highly anticipated. Fast and slow light technology has the ability to regulate the speed of light, It can be used to solve the problem of synchronization and buffer of signal light in all-optical communication network, to realize optical switching and optical routing, and to solve the key problem in the process of all-optical network communication. In recent years, the technique of fast and slow light in optical fiber is a hot topic, and the fast and slow light based on stimulated Brillouin scattering (SBS) and stimulated Brillouin scattering (SBS) effect has very low threshold power of pump light, which can be operated at room temperature. The advantages of adjustable working wavelength and good compatibility with optical fiber communication system are the research hotspot in the technology of adjusting the speed of light. In this paper, Brillouin scattering (Brillouin scattering) generation of fast light is taken as the research object, and the time advance is improved. To reduce pulse distortion, the characteristics of narrow bandwidth pump light and wide band wide pump SBS in optical fiber are discussed and studied respectively. The main contents are as follows: 1. The various control techniques for realizing fast and slow light are introduced and compared. Based on stimulated Brillouin scattering, this paper mainly discusses how to increase fast light advance and reduce pulse distortion in recent years. The present situation and application prospect of using special optical fiber to improve the advance efficiency. 2. The physical model of Brillouin scattering process in optical fiber and the mathematical push-down process are given, considering the different conditions of producing fast and slow light in optical fiber, The coupling equations of stimulated Brillouin scattering acoustic wave and light wave are improved, and the analytical solution of the small signal model of SBS fast light is studied based on the stimulated Brillouin scattering coupling equation, taking the monochromatic pump light as an example. The time advance and pulse compression factor of fast light are obtained respectively. Based on the coupled equations of stimulated Brillouin scattering, small signal analysis is used. The signal optical pulse advance and deformation of high nonlinear fiber are studied. The results show that the signal optical pulse time advance increases approximately linearly with the increase of input signal optical power and transmission distance in a certain range. At the same time, the pulse compression degree is strengthened, and the time advance of nonlinear fiber is larger than that of ordinary single-mode fiber under the same condition. When the signal light energy is 50 MW, the time advance of 203ns and the smaller pulse deformation are realized in the 50m high nonlinear fiber. The fast optical advance efficiency of the high nonlinear fiber is improved significantly, and the pulse deformation is significantly reduced. The results are of reference significance for the realization and application of fast light. 4. A method of realizing Brillouin broadband fast light using pump light with multiple spectral lines is proposed. The Brillouin absorption characteristics and the corresponding phase changes of Brillouin pumped by broadband pump corresponding to multiple spectral lines are analyzed. It is concluded that the broadband absorption spectrum can be obtained by the superposition of the equal-amplitude spectral lines, and the absorption spectrum width increases with the increase of the number of spectral lines. Moreover, the line spacing has a serious effect on the linearity at the bottom of the absorption spectrum. The theory of wide band SBS is also introduced, and the Brillouin advance characteristics of the broad band pump light of Gao Si spectrum and the flat-top pump light of rectangular spectrum are discussed, respectively. The results show that the fast light can reduce the distortion of the pulse and maintain the transmission of the original pulse waveforms to a large extent by using the broad band pump light of Gao Si spectrum and the flat-top pump light of rectangular spectrum. Under the same condition, the pulse distortion of rectangular flat-top pump is smaller than that of Gao Si.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN253;TN929.1

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