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题名	Nd:YAG陶瓷激光器和掺镱双包层光纤激光器热沉积研究
作者	朱洪涛
学位类别	博士
答辩日期	2006
授予单位	中国科学院上海光学精密机械研究所
导师	楼祺洪
关键词	半导体激光器泵浦固体激光器 Nd:YAG陶瓷激光器 双包层光纤激光器 热沉积
其他题名	Research on the heat deposition in Nd:YAG ceramic laser and Yb-doped double cladding fibre laser
中文摘要	使用半导体激光器作泵浦源可以有效减少固体激光介质中的热沉积，但是随着泵浦功率的提高，半导体激光器泵浦固体激光器中的热沉积仍然是制约高功率固体激光器发展的重要因素。本工作以实验室所建立的Nd:YAG陶瓷激光器和掺Yb3+双包层光纤激光器为研究对象，进行热沉积问题的基础研究。 本工作首次从粒子数守恒和能量守恒定律出发，建立Nd:YAG陶瓷激光器的发热模型，并首次提出通过测量激光器的斜率效率来推算激光介质中的热沉积的方法。在发热模型的基础上，对影响陶瓷激光器增益介质内热沉积的因素进行理论分析。研究结果表明，增益介质内的热沉积对激光提取效率、光束交叠效率、泵浦量子效率、材料掺杂浓度以及泵浦波长等因素变化很敏感。本研究结果对降低激光介质内的热沉积，提高激光器斜率效率具有重要现实意义。通过优化设计，实验室所建立的钛宝石端面泵浦Nd:YAG陶瓷激光器和LD侧面泵浦Nd:YAG陶瓷激光器的斜率效率分别达到59.8%和62%。 本研究工作首次对双包层光纤激光器的热沉积问题作实例分析，以我们小组的四百瓦级光纤激光器为研究对象，定量分析了光纤内的二维温度分布。根据本工作采用的双包层光纤传热模型，在给定热载荷条件下，研究双包层光纤结构以及光纤表面对流换热系数等对双包层光纤散热能力的影响。研究结果表明光纤的温升对光纤表面对流换热系数的变化非常敏感，并确定出如果要把本小组的四百瓦光纤激光器提高到千瓦水平，光纤泵浦端附近表面对流换热系数要大于2.8×10-2W.cm-2.K-1。在此基础上设计出高功率双包层光纤激光器泵浦输出端冷却装置，该装置获得专利并成功应用在激光系统，实现千瓦级激光输出。 对双包层光纤激光器的热沉积问题的研究工作可为双包层光纤的优化设计、提高光纤自身的散热能力提供依据；为实现泵浦方式和泵浦结构的优化设计，提高光纤激光器的热处理能力提供理论参考；特别是对冷却方案的设计，研制安全、稳定运行的千瓦级光纤激光器具有重要的指导意义；同时也为本课题组开展973研究项目打下基础。
英文摘要	Heat deposition in solid state laser can be effectively reduced by using the diode lasers as pumping source. However, when the pumping power increases, heat deposition in diode pumped solide state laser (DPSSL) is still the bottleneck in the development of high power solide state lasers. Research on heat deposition in Nd:YAG ceramic laser and Yb3+ doped double cladding fibre(DCF) laser, which were built in our lab, is carried out in this dissertation. Based on the conservation of particle number and the law of conservation of energy, a heat deposition model of Nd:YAG ceramic laser is developed. A method to measure the heat generation in laser medium is proposed for the first time, which is deduced from the slope efficiency of laser device. Based on this model, some factors relative to the heat deposition in laser medium are discussed. Numerical simulation results show that the heat deposition is sensitive to the changes of laser extraction efficiency, beam overlap efficiency, pumping quantum efficiency, concentration, and wavelength of pumping source. The results of this work are valuable for the decrease of heat generation in laser medium and the increase of the slope efficiency of laser device. Through optimizing the design of laser devices, the slope efficiencies of the Ti:sapphire end-pumped Nd:YAG ceramic laser and the LD side-pumped Nd:YAG ceramic laser built in our lab are 59.8% and 62%, respectively. The two-dimenstion distribution of heat deposition in the practical 400W double cladding fibre laser is quantitatively analyzed for the first time. The results show that the distribution of heat deposition in the double-end-pumped DCF laser is very uneven. The heat deposition near the pumped ends is severe, and the heat deposition in the middle part is relatively low. Based on the heat dissipation model developed in this dissertation, factors influencing on the ability of heat dissipation of DCF are studied. The results show that the temperature rise of fibre is very sensitive to the variation of convective coefficient. If the output power of the 400W DCF laser increases to 1 kW, the convective coefficient near the pumped ends should be more than 2.8×10-2W.cm-2.K-1 to ensure the DCF laser works safely and steadily. The patent, which is the cooling device for high power DCF laser’s pumping ends, is successfully used in laser system, and the output power of 1kW is abtained. The results of the research on heat deposition in DCF lasers are valuble for the designs of DCF, the pumping method and pumping structure, the cooling method, and etc. By increasing the DCF’s and the DCF laser’s ability of heat dissipation, the safe and steady DCF laser with the output power of 1kW will be built. At the same time, this work will lay the foundation for the 973 sub-project, which are carried by our team.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15462]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	朱洪涛. Nd:YAG陶瓷激光器和掺镱双包层光纤激光器热沉积研究[D]. 中国科学院上海光学精密机械研究所. 2006.

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