拉曼光纤激光器中高阶stokes产生的研究
毕业论文关键词：拉曼光纤激光器 斯托克斯效应 光谱演化
High-order Stokes signals generation in a Raman fiber laser
Abstract: Limited by the emission wavelength in typical rare-earth-doped fiber lasers, laser sources with special wavelength are mainly developed depending on the nonlinear effects. The Raman fiber lasers, based on the stimulated Raman scatting effect, have attracted considerable attention due to their unique characteristic. Theoretically, the Raman fiber laser can generate arbitrary wavelength via the multi-order Raman frequency shifts with suitable pump source and fiber. In this paper, the high-order Stokes signal generation in a Raman fiber laser was studied. A Q-switched Er,Yb fiber laser and a Raman fiber amplifier were constructed respectively. The Q-switched Er,Yb fiber laser provided a maximum average output power of 13.1W at 1564nm with pulse width of 221ns when the frequency rate was 100kHz. With the pump source, three orders Stokes signals were obtained in the Raman fiber amplifier with 3.8km multimode graded-index silica fiber. The center wavelengths located at 1685 nm, 1830 nm and 2000nm, respectively. A maximum total output power of 1.9W was obtained in the Raman fiber amplifier. Spectra and power evaluation of every Stokes signal were analyzed and discussed.
Keywords：Raman fiber laser Stokes effect spectrum evaluation
目录
摘要 I
Abstract II
第一章 绪论 1
1.1光纤激光器简介 1
1.2拉曼光纤激光器应用和分类 2
第二章 拉曼光纤激光器工作原理 4
2.1自发拉曼散射 4
2.2受激拉曼散射 5
2.3级联拉曼光纤激光器 7
第三章 主动调Q Er,Yb光纤激光泵浦源 8
第四章 脉冲泵浦的拉曼光纤放大器 11
4.1 光谱特性 12
4.2 功率特性 13
4.3脉冲特性 15
总结 17
致 谢 18
参考文献 19
第一章 绪论
光纤激光器以其结构紧凑、高光束质量、高效率等众多的优点，引起了人们的极大关注[1]。早期的光纤激光器件由于输出功率小，其应用领域受到限制。二十世纪九十年代初人们发明了双包层光纤结构，自此光纤激光器的输出功率得到了大幅度的提高，直到现在为止光纤工作物质的性能已经超越了块状工作物质[2]。光纤激光及其应用经过最近几十年的发展与完善，现今已经成为激光领域一个新的研究热点[3]。其中，拉曼光纤激光器是以受激拉曼散射为基础的光纤激光器，因为其新颖的激光特性和潜在应用价值而引起越来越多研究人员的关注。不过在国内对拉曼光纤激光器的研究仍有一些限制因素，例如使拉曼光纤激光器的光纤实现级联输出所必备的光纤布拉格光栅对技术的要求比较高而且工作波长特殊，处理及加工相当的困难[4-6],国内目前能对应此光纤激光器的光栅产品还很少。本篇文章就是对拉曼激光器进行初步的研究。实验的研究对象是拉曼光纤激光器的光谱演化及高级斯托克斯效应的产生，这里主要介绍二级斯托克斯效应。首先介绍拉曼光纤激光器和它的工作原理并通过在实验中获得的拉曼光纤激光器输出光谱来阐述二阶斯托克斯效应的产生。实验中我们根据输出光谱计算功率分布，进一步确定高阶斯托克斯效应与泵浦光功率之间的关系。实验研究目的在于进一步了解拉曼激光器，让我们对拉曼激光器的功能和性质有更好的认识和掌握。