【作者】 张颖；

【导师】 张茹；

【作者基本信息】 北京邮电大学 ， 物理电子学， 2010， 硕士

【摘要】 随着光纤通信的迅猛发展,对通信带宽的需求也越来越大,全光通信的发展势在必行。慢光技术由于其可控光速的能力和在全光通信中的应用受到人们的广泛关注。在各种慢光系统中,光纤慢光的科学研究是近期慢光研究的热点,而利用光纤受激布里渊散射(SBS:Stimulated Brillouin scattering)效应实现慢光是慢光走向实际应用的关键。非线性光纤由于具有极强的非线性特性,在受激布里渊散射等方面具有优异的表现。研究基于非线性光纤的受激布里渊散射慢光可调谐延迟,具有十分重要的意义。本文首先概述了光纤中慢光技术的研究现状。基于对自行研制的掺杂纳米微粒InP新型非线性光纤的分析,总结基于非线性光纤的受激布里渊散射慢光的特点。对掺杂纳米InP微粒的新型光纤进行数值计算,得出在布里渊增益G约为15时得到一个约为738ps的慢光延迟。同时计算相同条件下普通单模光纤中的慢光,比较得出非线性光纤能在较短的距离产生了光纤内泵浦能量的转移并产生慢光延迟。基于以上分析,搭建实验系统测量非线性光纤、单模光纤以及光子晶体光纤的慢光参数,测得1km的非线性光纤的布里渊阈值为17.8dBm/60mw,布里渊频移为13.3GHz；布里渊增益谱宽为65MHz,较一般单模光纤的增益谱宽要宽(36MHz),且增益谱相对稳定；非线性光纤的布里渊单位最大峰值功率为0.032mw/km,大于单模光纤中的值。通过搭建不同的慢光实验系统实验,比较分析泵浦光和信号光匹配方法,并最终利用手动匹配法,根据已经测量得出的非线性光纤的慢光参数值,在非线性光纤中进行慢光实验,在输入信号为1555.8174nm时,得到脉冲为140ns的信号最大延迟为8ns，比输入为1555.8162nm和1555.8184nm时延迟增加了6ns和4ns；延迟随着泵浦功率的增加而增大,输入泵浦功率为18.5dBm时的延迟比输入为17.8dBm时增加了4ns左右。通过以上分析实验得出,由于纤芯较强的模场限制作用和光纤非均匀性的提高,非线性光纤中的布里渊效应及慢光效应会增强；同时非线性光纤中的布里渊增益谱宽也较大,有效增加了SBS慢光的有效谱宽范围,且较稳定的增益谱也较利于光纤中慢光的实现。文章最后讨论非线性光纤中受激布里渊散射慢光的脉冲畸变和信号失真,研究拓宽布里渊增益谱减小传输失真的方法,为课题的进一步研究指明了方向,并且为非线性光纤中慢光技术走向实际应用奠定了基础。更多还原

【Abstract】 With the exponential growth of communication requirement and the fast development of Optical Fiber Communication, Slow light draws a great of interests. Especially, slow light based on Stimulated Brillouin scattering (SBS) shows possibility to achieve the practical application. Nonlinear fiber has excellent performance in SBS for its high nonlinearity, and it has great significance to research the SBS slow light based on the nonlinear fiber.First of all, Based on the optical fiber doped with nano-material InP, the characteristics of SBS slow light in this nonlinear fiber are concluded. Calculate the SBS model in this fiber, a considerable time delay of-738ps is obtained, which shows much strong SBS process and energy diversion in shorter length than single mode fiber under the same conditions.Based on the analyze mentioned above, experimental systems are set up to measure the slow light parameter. The results shows the Brillouin threshold of 1km nonlinear fiber is 17.8dBm/60mw. The Brillouin gain spectrum width is 65MHz, which is more wider and stable than that in single mode fiber(36MHz). The measured unit Brillouin maximum peak power(0.032mw/km) is greater than the value of single-mode fiber.By setting up three different experimental systems to compare and analyze the performance of pump light and signal light matching, the manual matching method is finally chosen into the SBS slow light system based on the nonlinear fiber. when the input signal pulse is 1555.8174nm(140ns), a maximum time delay of 8ns is obtained. With fixed wavelength, the signal delay increases with increasing pump power, compared with the delay under input 17.8dBm, the value is about 4ns more under 18.5dBm input.Based on the research above, a conclusion is achieved, that due to the strong restrictive effect of the fiber mode field and the higher non-uniformity, the slow light in nonlinear fiber is enhanced. Meanwhile, the Brillouin gain spectrum width is expanded, which leads a wider range of effective slow light. Moreover, the more stable gain spectra is conducive for the realization.Finally, the signal distortion and pulse aberrance are discussed. Then research broadening Brillouin gain spectrum methods to reduce the transmission distortion, which leads a way for continuous research in this project, moreover, establishes the foundation for the practical application of the slow light based on nonlinear optical fiber.更多还原