【作者】 马会芳；

【导师】 黄永清；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2013， 博士

【摘要】 本论文的研究工作是围绕以下项目展开的：以任晓敏教授为首席科学家的国家重点基础研究发展计划项目(项目编号：2010CB327600)；国家自然科学基金项目(项目编号：61077049)；新世纪优秀人才支持计划项目(项目编号：NCET-08-0736)和高等学校学科创新引智计划项目(项目编号：B07005)。超连续谱光源具有光谱范围宽、稳定性高等优点,在光通信系统、光度量学及生物医学等方面都有重要的应用。本论文主要对光通信用超连续谱的产生及其性能优化进行了理论和实验研究,主要研究内容和创新点如下：1.从光场的量子理论出发,推导得出了脉冲在光纤中传输时所遵循的含自发拉曼散射噪声的非线性传输方程。讨论了适用于求解该方程以及广义非线性薛定谔方程的数值方法：与对称分步傅里叶法结合的相互作用绘景中的四阶龙格-库塔法。2.基于广义非线性薛定谔方程,理论分析了在正常色散区超连续谱的展宽机制；讨论了光纤参量和泵浦脉冲对超连续谱宽度、平坦度的影响。在此基础上,设计了一种具有近零正色散值、色散平坦的高非线性微结构光纤,利用该光纤可在1550nm波段产生宽带、平坦的超连续谱。3.理论分析了泵浦脉冲的散粒噪声对光纤中超连续谱宽带幅度噪声的影响。以相对强度噪声,对正常色散区超连续谱宽带幅度噪声做了定量分析,结果表明：噪声沿光纤传输中有两次显著地放大,第一次噪声放大是由光谱初始展宽过程巾巾心部分的剧烈分裂造成的,是光谱展宽过程中固有的噪声放大；第二次噪声放大是由脉冲内拉曼散射效应带来的非线性能量损耗造成的,是造成超连续谱宽带幅度噪声放大的主要原因。通过合理设计光纤的色散特性可有效抑制脉冲内拉曼散射效应。4.利用高阶孤子压缩效应,实现了对微结构光纤中产生的超连续谱的展宽,光谱-10dB宽度由75nm展宽至140nm。对上述超连续谱的低频幅度噪声进行了定量分析,结果表明：当泵浦脉冲功率在压缩光纤中满足整数阶的高阶孤子,且压缩光纤的长度短于孤子发生分裂的长度时,获得的压缩脉冲可在增加超连续谱宽度的同时不引起光谱低频幅度噪声的恶化。5.分析了超连续谱的平坦度对泵浦脉冲脉冲沿陡峭程度的敏感性,结果表明：脉冲沿较为陡峭的脉冲产生的超连续谱具有更好的平坦度。与人合作,利用双通道Littman-Metcalf滤波器改变脉冲沿的陡峭度,实现了对超连续谱平坦度的优化。更多还原

【Abstract】 This work was supported by National Basic Research Program of China (2010CB327600), National Natural Science Foundation of China (61077049), Program for New Century Excellent Talents in University of China (NCET-08-0736) and the111Project of China (B07005).The supercontinuum(SC) has the advantages of both broadband and high-stability. These properties should make the SC an ideal tool for important applications including optical communication system, biomedicine, optical measurement, etc.. In this dissertation, the generation and performance optimization of SC used for optical communication systems are studied both theoretically and experimentally. The main contents and achievements are as follows.1. According to the quantum theory of light field, the nonlinear propagation equation contains spontaneous Raman scattering was deduced to model pulse propagation in fiber. And the numerical method-the Fourth-order Runge-Kutta in the Interaction Picture combined with split-step Fourier method-is discussed to compute the above equation and the generalized nonlinear Schrodinger equation.2. Based on the generalized nonlinear Schrodinger equation, the mechanism of SC generation in normal dispersion regime is demonstrated theoretically. The effect of fiber parameters and pumping conditions on the bandwidth and flatness of SC generation in Microstructured Fiber (MF) are discussed in detail. A dispersion-flattened MF with small normal dispersion and high nonlinear are designed for flat broadband SC generation in1550nm region.3. The effect of shot noise of pump pulse on the broadband amplitude noise of SC generated in fiber is investigated numerically. The relative intensity noise is used to analyze the broadband amplitude noise of SC generated in normal dispersion regime quantitatively, the results show that, the noise suffers twice obvious amplifications in the process of SC generation, the first time is caused by the initial spectral severe split and is inherent, the second time is caused by the nonlinear energy loss in the presence of intrapulse Raman scattering (IRS) and is the main reason of the amplification of broadband amplitude noise during SC generation. The IRS effect can be suppressed by using MF with suitable dispersion characteristics.4. Using high-order soliton compression effect, enhancement of bandwidth of SC generated in MF by using compressed pulse is demonstrated, the measured-lOdB spectral width is broadened from75nm to more than140nm. The low-frequency noise of SC spectrum generated by compressed pulse is analyzed quantitatively. Numerical analysis shows that using the certain peak power pulse compressed by a certain length fiber can increase the spectral bandwidth without making extra low-frequency amplitude noise.5. The dependence of the flatness of SC on the steep degree of pump pulse is discussed in detail. The results show that the flatness of SC spectrum generated by the pulse with more steep pulse is better. The flatness of SC generation in MF is improved by filtered the pump pulse using a double-pass Littman-Metcalf filter before injected into MF.更多还原