【作者】 卓兆亿；

【导师】 陆培祥；

【作者基本信息】 华中科技大学 ， 物理电子学， 2009， 硕士

【摘要】 双包层光纤激光器兼具了传统固体激光器和光纤激光器的优点,在工业、光通信、医学、军事等各个社会领域得到了广泛的应用,并具有重要的研究价值从而愈发得到研究者们的重视。本文回顾了光纤激光器的发展历史,概述了掺镱双包层光纤激光器的研究现状。简要介绍了它的基本原理、谐振腔组成结构及泵浦耦合方式。从理论上对双包层光纤激光器的一些关键技术环节进行了较深入的研究。主要内容包括:(1)从掺镱双包层光纤激光器的稳态速率方程出发,得到了可用于数值模拟的微分方程组。并通过计算,分析了光纤长度、腔镜反射率、纤芯掺杂浓度、传输损耗、泵浦光波长等因素对掺镱双包层光纤激光器输出特性的影响。(2)从稳态热传导方程出发,分析了不同光纤结构对稳态运行时光纤内部温度分布的影响。指出,只要对系统进行简单的风冷或水冷结构设计,将大幅改善其散热性能。(3)利用二维射线法及模式判别法对圆对称内包层及纤芯偏置内包层对泵浦光的吸收效率做了分析。结果表明,对纤芯进行偏置将大幅度提高其对泵浦光的吸收效率。(4)从速率方程和耦合方程出发,在考虑受激喇曼散射的情况下,利用数值方法,分别得到了在正向及反向泵浦条件下,光纤内泵浦光、信号光及斯托克斯光功率的分布。详细分析了各因素对掺镱双包层光纤激光器中受激喇曼散射的影响。模拟结果能够对掺镱双包层光纤激光器,特别是高功率条件下的优化设计提供一定的理论指导。更多还原

【Abstract】 Cladding pump technology makes the fiber couple high-power multimode pump better and keep the output beam quality high, results in greatly increasing the output power of fiber laser. Because of its advantages, it is widely used in various social fields, including industry, medical, communications, military and so on. In this paper the development of fiber laser has been reviewed and an overview of the research of Ytterbium-doped double-clad fiber laser has been given, whose basic principles, resonant cavity structure and pump coupling patterns have been briefly introduced. This paper mainly contains the following aspects:(1) Based on the steady-state rate equation of Ytterbium-doped double-clad fiber laser the differential equations have been derived for numerical simulation. The impacts which will influence the output characteristics of Ytterbium-doped double-clad fiber laser have been analyzed by calculating.(2) Based on the steady-state heat conduction equation, the fiber’s internal temperature distribution in different fiber structures has been discussed.(3) The internal-clad forms are very important in double-clad fiber laser, and the pump absorption efficiency in circular symmetry internal-clad and core bias internal-clad has been researched in the geometrical optics method and mode analysis method. The results demonstrate that the pump absorption efficiency will be highly improved when the fiber core is deflective.(4) Based on the rate equation and coupled equation, the power distributions of pump, signal light and Stokes light in fiber have been studied when the pump is forward and backward. The impacts which will influence the stimulated inelastic scattering in Ytterbium-doped double-clad fiber laser has been analyzed.The research results can direct the Ytterbium-doped double-clad fiber laser optimization design under the conditions of high-power.更多还原