LD泵浦掺镱双包层光纤激光器的研究

【作者】 梁兰菊；

【导师】 郑义；

【作者基本信息】 曲阜师范大学 ， 物理电子学， 2005， 硕士

【摘要】 自从20世纪80年代后期以来,由于包层泵浦技术重大的突破,光纤激光器的研究取得了前所未有的进展,并以优异的性能和广泛的应用前景成为国际光电子行业的热门课题。本文从理论和实验两方面对掺Yb³⁺双包层光纤激光器进行了深入的研究。主要包括以下内容: 1.详细地概述了国内外双包层光纤激光器的研究进展和主要应用,指出研究双包层光纤激光器的重要意义。 2.从Yb³⁺的能级结构及其性质出发,结合Yb³⁺离子的吸收和发射光谱,对掺Yb³⁺光纤激光器泵浦源的选择进行了分析。接着又分析了掺Yb³⁺双包层光纤激光器几何结构以及内包层的形状对双包层光纤吸收效率的影响。 3.考虑到双包层光纤激光器的特殊结构、自发辐射和光纤的分布损耗等因素建立速率方程理论模型,利用龙格—库塔法（Rounge-Kutta）求出输出功率、增益特性等与光纤长度的关系,再根据速率方程理论推导双包层光纤激光器泵浦阈值、斜率效率等表达式。通过数值模拟计算,得到在一定的泵浦功率下存在最佳光纤长度,计算还表明输出镜的反射率越小光纤激光器的输出功率越大,可以采用光纤端面作为输出镜。自发辐射和光纤的分布损耗对光纤激光器有一定的影响。特别是对于大功率双包层光纤激光器,必须考虑自发辐射功率、光纤的分布损耗等因素。 对双包层光纤激光器泵浦源的配置方式进行了理论优化。分析不同泵浦方式下泵浦光、激光输出功率和增益特性在光纤中的分布,综合分析得出双端非对称泵浦比较适合大功率光纤激光器。 4.采用典型F-P腔掺Yb³⁺双包层光纤激光器的实验装置,对梅花形掺Yb³⁺光纤激光器的输出特性进行了详细的实验研究。在976nm激光二极管尾纤输出功率18.29W泵浦下,获得大于8.48W的激光输出功率。激光斜效率达到54.42%,光光转化效率为46.36%。更多还原

【Abstract】 Great improvement has been achieved in high power fiber lasers with the breakthrough of clad pumping technique since the last period of 1980s. And it has become a focus of concern in the field of optoelectronics worldwide for their excellent performance and abroad of application. In this thesis, Yb~3+-doped Double Clad Fiber Lasers(Yb~3+-DCFLs) have been studied in experimentally and theoretically. The main subjects are as the following:1. Brief Review of the History, Development and Applications of Yb~3+-DCFLs. And it pointed out the significance of the research of double-clad fiber lasers.2. According to the characteristic of the energy level structure and spectrum of Yb , we gave the theoretical analyses about the choice of pump source .And we also analysis the influence of different inner clad shape on the absorptive efficiency of double clad fiber laser.3. The rate equations of theory Yb~3+-DCFL is constituted ,which include the effect of the distribution waster along the fiber with and Spontaneous emission . By using the rate equations and Rounge—Kutta way, output power and the threshold characteristics of DCFL are analyzed theoretically, such as the fiber length and cavity reflectivity are analyzed with a comprehensible model . It is found that there is an optimum fiber length in DCFL at a defined pump power, and output mirrors with low reflectivity is better for high gain fiber lasers. And It is found that the distribution waster along the fiber with and Spontaneous emission are effect the output power, we consider them.influence especially high power fiber lasers.The LD pumping scheme of Yb~3+-DCFLs is studied by using numerical calculation .It is shown that two-end pumping is the best choice for high power fiber lasers for the reason that it can reduce the power density on the input fiber end and can get a more uniform gain profile as well as power更多还原