【作者】 杨超；

【导师】 陆培祥；

【作者基本信息】 华中科技大学 ， 光电信息工程， 2008， 硕士

【摘要】 光纤激光器是一种新型固体激光器,其特点是使用双包层掺杂稀土离子光纤作为增益介质。因为光纤本身的特性,使得光纤激光器比其它固体激光器具有明显的优势,如:易于散热,光束质量好,转换效率高,系统灵活可靠等。这些优点使光纤激光器受到十分广泛的关注,并成为固体激光发展的主要方向之一。光纤激光器已经广泛进入实际应用,涉及激光加工,军事,光通信和激光理疗等领域,获得了很好的效果。目前为了获得更高功率输出且不破坏光束质量的光纤激光,出现了光纤激光器的相干合束技术。光纤合束器作为能够实现相干合束的无源光器件,具有很好的应用前景。本文主要对光纤激光器的基本原理进行了研究,搭建了光纤激光器实验平台,在实验中对参数进行了测量和分析并进行优化,采用合束泵浦的方式获得了20W的连续激光输出。对于光纤合束器的基本制作工艺进行了初步研究。在合束泵浦光纤激光器实验中,对LD泵浦源进行了有效风冷,将波长漂移控制在915nm附近的最佳范围之内,在多LD合束的情况下光谱宽度为6nm。测试了光纤合束器的基本参数并用于指导实验,并对其进行了冷却处理。采用截断法实际测量了有源光纤的吸收系数,并以此为依据确定实验中光纤的最佳长度为22m。该长度与实验中输出功率的最优长度吻合。同时,实验验证了由于重吸收的存在,激光波长随有源光纤长度增加而增加的关系。利用双透镜系统进行端面耦合调节,在整体实验中获得了以下结果:4×1合束泵浦实验,输出功率10.5W、斜率效率斜65%,整体转换效率为46%;6×1合束泵浦实验,输出功率20.5W、斜率效率斜75%。对熔融拉锥光纤合束器的制作进行了初步的研究,摸索了制作过程的基本工艺。掌握了光纤涂层的有效处理方法,分析了拉锥过程中的各项参数的影响,制作了合束器锥区实验品。更多还原

【Abstract】 As a new type of solid laser, fiber laser is characterized by the rare earth ions doped double cladding fiber as a gain media. Benefiting from the special configuration of fiber waveguide, the fiber laser has performed much better then the other solid lasers in the following fields: better cooling condition, excellent beam quality, high efficiency and flexibility. All of these advantages, which make the fiber laser one of the primary schemes of future solid lasers, are very attractive all around the world. Actually the fiber laser has been widely applied in the fields of manufacturing, military, communication and therapy successfully. At present the coherent combining is studied for the higher output without the descend of beam quality. So the fiber combiner as a passive component, which makes the coherent combining available, has great potential. The basic theory of fiber laser is studied here. The integrated system of fiber laser is built up. With the combined pump source the max 20W output is obtained. The technique of fiber combiner is explored too.The efficient air cooling is employed to control the wavelength of LDs around 915nm in the experiment of fiber laser with combined pump sources, which makes the width of wavelength 6nm when 6 LDs operating. Test the combiner and the water cooling is employed. The pump coupling is carried out with a two-lens system practically. The absorbing coefficient is test by cutting the active fiber, which helped us to decide the best length in the later experiment, 22m. The length is tally with the experiment result well. Meanwhile, the reabsorption is validating. The holistic experiment has the result as follows: in the 4×1 pump experiment, output of 10.5W, slope efficiency of 65% and 46% for holistic efficiency are obtained; in the 6×1 pump experiment 20.5W output and slope efficiency of 75% are obtained.The technique of tapered fused bundle combiner is explored. The method of removing the coating of fiber is mastered. The parameters of tapering are studied. And rough tapers are obtained.更多还原