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基于光纤非线性效应的可控慢光技术研究

时间:2019-01-05 19:34来源:毕业论文
光纤中的受激布里渊散射(SBS)具有波长可以任意选择、阈值功率低、可在室温下进行、容易兼容到现代光通信系统等优点,使其在慢光技术、激光器以及传感技术等方面很具应用潜力

摘要光纤中的受激布里渊散射(SBS)具有波长可以任意选择、阈值功率低、可在室温下进行、容易兼容到现代光通信系统等优点,使其在慢光技术、激光器以及传感技术等方面很具应用潜力。本论文对光纤中的SBS的形成过程及实现慢光效应的原理进行了探究。探究要点如下:32266
1.光纤中 的产生过程及阈值分析
 是入射泵浦光、斯托克斯(Stokes)光和声波三者之间进行的非线性作用。微观上考虑,可以把SBS过程可以看做泵浦光子、散射光子和声学声子间的互相作用,在此过程中,一个泵浦光子的消失的同时会产生一个散射光子和一个声学声子,这一过程使得散射光场和声波场得到增强。散射过程中所产生的散射光子中,一部分光子频率会小于泵浦光子的频率,这个过程叫作Stokes散射,另一部分大于泵浦光子频率,这个过程叫作anti-Stokes散射[1]。
 的阈值功率要比受激拉曼散射的阈值功率低两个数量级以上,因此 更容易在光纤中实现。 的阈值功率影响因素有很多,本文分别对光纤长度、有效纤芯面积、声子寿命等因素对阈值功率的影响作了探讨,此外,泵浦光的偏振状态、光纤材料的工艺瑕疵等因素也会对阈值功率产生影响。
2.利用分步傅里叶变换(SSFT)处理光纤中的
在对 的非线性效应进行数值处理过程中,SSFT可以有效地解决耦合波方程组中非线性微分方程难以求解的问题。论文中,我们尝试用SSFT进行对 过程进行模拟仿真。和有限差分法相比,SSFT具有更快的运算速度。
3.利用 实现慢光效应并改善其带宽
通过光纤介质内的受激散射增大Stokes光的群折射率,从而使Stokes光的群速度大大降低。由于 慢光系统中可获得带宽最大值为 量级,对光通信中的数据传输率产生很大限制。我们介绍使用多个独立泵浦源的方法,使慢光带宽得到很大提升。 源自$六l维,论:文w网)加7位QQ3249^114 www.lwfree.cn
关键词  受激布里渊散射  受激拉曼散射  斯托克斯  阈值功率  分步傅里叶变换  非线性光学
毕业论文设计说明书外文摘要
Title Study of controllable slow light technology based on fiber nonlinearity                                                              
Abstract
  Stimulated Brillouin Scattering (SBS) in fiber has potential applications in the slow light technology, lasers and sensing technology because of its arbitrarily chosen wavelengths, low threshold power, room temperature operation and ease compatibility with modern optical communication systems. In this paper, we have studied the processes of SBS in optical fiber as well as related principle to achieve the slow light. The major points are as follows.
  1. Generation of SBS in optical fiber and the analysis of its threshold.
SBS is the nonlinear interactions among pump light, sound waves and Stokes wave. According to quantum optics theory, SBS is the nonlinear interactions among pump photons, acoustic phonons and Stokes phonons. In this process, a pump photon annihilation produces a scattering photon and an acoustic phonon, which enhances the scattering light and the acoustic wave. Part of the scattered photons have lower frequencies than the pump photons, the process is called Stokes scattering; others have higher frequencies and are thus called anti-Stokes scattering.
The threshold power of SBS is typical two orders higher than that of SRS, therefore SBS is much easier to achieve in optical fibers. There are many factors related to the threshold power of SBS. We have studied the effects of the fiber length, the effective core area and phonon life in this paper. In addition, the pumping power threshold is also affected by the polarization state, the defects of dielectric materials and etc. 基于光纤非线性效应的可控慢光技术研究:http://www.lwfree.cn/tongxin/20190105/28768.html
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