标题: | 半导体雷射激发光纤雷射系统之物理与技术 Physics and technology of diode-pumped fiber laser systems |
作者: | 黄哲彦 Huang, Je-Yen 陈永富 Chen, Yung-Fu 电子物理系所 |
关键字: | 光纤雷射;脉冲雷射;高功率雷射;Q开关;饱和吸收体;掺铬钇铝石榴石;半导体饱和吸收体;波长可调;fiber laser;pulse laser;high power laser;Q-switch;saturable absorber;Cr:YAG;semiconductor saturable absorber;wavelength tunable |
公开日期: | 2008 |
摘要: | 本文主要使用双包层之掺镱及铒镱共掺之大模态光纤(掺镱光纤之纤核直径:30μm,铒镱共掺光纤之纤核直径:25μm)作为研究雷射二极体激发之高功率光纤雷射的特性。首先我们使用窄频宽的薄膜濾光片作为控制雷射纵模之元件,完成了波长可调且窄波段的的光纤雷射; 之后则建立了被动式及被动式的Q开关光纤雷射。在被动式Q开关中,首先是使用掺镱之光纤作为增益介质。我们分别使用Cr:YAG晶体以及半导体材料AlGaInAs作为饱和吸收体。在以Cr4+:YAG晶体作为饱和吸收体的实验中可得到脉冲能量为350 μJ;在以半导体作为饱和吸收体 的实验中,实验结果其可操作在5~30 kHz且脉冲能量约为 450 μJ。另外在使用铒镱共掺光纤作为增益介质的实验中,我们亦利用同样材料的半导体但比例不同而使其吸收波段在1.5 μm來作为饱和吸收体。结果在13.5 W的激发功率之下可得到平均功率为1.26 W,脉冲能量为100μJ及重覆率为12 kHz输出。主动式Q开关光纤雷射中我们采用声光晶体來产生腔内的损耗,我们测试了几种不同的方法來 增加声光晶体的调变损耗以提升脉冲波能量。实验结果可得到600 μJ的脉冲能量及42ns的脉冲宽度。 An Yb doped large-mode-area (LMA) fiber with a core diameter of 30 μm and an inner cladding diameter of 250 μm, and an Er/Yb codoped fiber with a core diameter of 25 μm and an inner cladding diameter of 300 μm have been used for researching in development of high power fiber lasers. Firstly we demonstrated tunable and narrow linewidth Yb and Er/Yb fiber lasers by use of thin film narrowband filters. Afterwards we have demonstrated passively and actively Q-switched fiber lasers. By use of Yb doped fiber as the gain medium, we have obtained passively Q-switched fiber lasers by employing a Cr4+:YAG crystal and an AlGaInAs semiconductor material as saturable absorbers respectively. The results revealed that with a Cr:YAG as a saturable absorber in a diode-pumped Yb fiber laser, the laser could generate a pulse energy of 350 μJ at a repetition rate of 38 kHz. For the use of AlGaInAs based saturable absorber experiment, we have realized a pulsed laser with 450-μJ pulse energy and can be operated at pulse repetition rate of 5~30kHz. The pulse train is very stable of ~10% fluctuation. Besides, we also obtained a passively Q-switched Er/Yb codoped fiber by means of another AlGaInAs semiconductor saturable absorber. Greater than 0.1 mJ of pulse energy at a repetition rate of 12 kHz was generated. Finally in the actively Q-switched fiber lasers, by enhancing the loss modulation of the active Q-switch (acoustic-optical modulator), we have obtained pulse of 600-μJ pulse energy and 42-ns pulse width. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT009521811 http://hdl.handle.net/11536/38863 |
显示于类别: | Thesis |
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