增益导引—折射率交叉导引光纤的理论与实验研究

发布时间：2018-03-09 05:08

本文选题：增益导引-折射率交叉导引光纤　切入点：光纤激光器　出处：《南京邮电大学》2017年硕士论文　论文类型：学位论文

【摘要】：增益导引-折射率反导引(GG-IAG)光纤是近几年提出的一种新型的大模场光纤结构,从提出至今一直被受关注。本论文结合GG-IAG光纤的基本原理,提出了一种新型的增益导引-折射率交叉导引(GG-ICG)光纤的理论模型,并通过理论设计与仿真,研究了其功率分布和激光阈值特性;在此基础上,通过建立和求解三维的热传导方程,得到了GG-ICG光纤的温度分布,研究了各参数对其的影响;设计制备出掺钕磷酸盐GG-ICG光纤的玻璃材料,对其折射率分布进行了一系列的研究,具体工作如下:1.构建GG-ICG光纤的理论模型,建立了端面泵浦条件下掺Nd3+GG-ICG光纤激光器的速率方程,利用数值法求解光纤内的功率分布特性,并进行了对比。2.通过解析法求解了光纤激光器的阈值公式,分析了单端泵浦条件下各光纤参数对GG-ICG光纤激光器的阈值的影响,结果表明,在最佳掺杂浓度N=1×1020 cm-3,最佳纤芯半径a=45μm,阈值泵浦功率最低,当后腔镜信号光反射率R2s=0.85,光纤长度L=1 cm时,阈值达到最低值2.95 W。根据以上参数对GG-ICG光纤激光器进行了优化。3.建立了三维坐标下的光纤温度模型,并对掺Nd3+GG-ICG光纤激光器的热传导方程进行了推导,得出解析解,在此基础上对单端和双端泵浦的GG-ICG光纤的情况进行了数值模拟,讨论了包层半径,纤芯和包层折射率差等参数对GG-ICG光纤激光器的热效应的影响,为优化GG-ICG光纤激光器提供了理论参考。4.以磷酸盐玻璃为基础,设计了该掺Nd3+GG-ICG光纤的纤芯和包层的制备方案,讨论了该玻璃的制备工艺,研究了玻璃配方中个别组分对折射率的影响,通过调整配方,最终得到了使纤芯和包层的折射率曲线达到理论模型中的分布规律的纤芯和包层玻璃,测试了其折射率和热转变温度Tg,讨论了拉制GG-ICG光纤的可能性,同时,测试了该激光玻璃的光学性能,得到一系列性能指标,为后续拉制光纤提供了实验依据。
[Abstract]:GG-IAG fiber is a new type of large-mode fiber structure proposed in recent years, which has attracted much attention since it was put forward. In this paper, the basic principle of GG-IAG fiber is combined with the principle of GG-IAG fiber. In this paper, a new theoretical model of GG-ICG fiber is proposed, and the power distribution and laser threshold characteristics of GG-ICG fiber are studied by theoretical design and simulation. By establishing and solving three-dimensional heat conduction equation, the temperature distribution of GG-ICG fiber is obtained, the influence of various parameters on it is studied, the glass material of neodymium doped phosphate GG-ICG fiber is designed and fabricated, and the refractive index distribution of Nd-doped GG-ICG fiber is studied. The specific work is as follows: 1. The theoretical model of GG-ICG fiber is constructed, and the rate equation of Nd3 doped GG-ICG fiber laser under end-pumped condition is established. The power distribution characteristics in the fiber are solved by numerical method. The threshold formula of fiber laser is solved by analytical method, and the influence of fiber parameters on threshold value of GG-ICG fiber laser is analyzed under the condition of single end pump. The results show that, The optimum doping concentration is 1 脳 1020 cm-3, the optimum core radius is 45 渭 m, the threshold pump power is the lowest, when the optical reflectivity of the posterior mirror signal is 0.85, the length of the fiber is 1 cm. According to the above parameters, the temperature model of GG-ICG fiber laser is established, and the heat conduction equation of Nd3 doped GG-ICG fiber laser is deduced, and the analytical solution is obtained. On this basis, the case of single-ended and double-end pumped GG-ICG fiber is numerically simulated. The influence of parameters such as cladding radius, core and cladding refractive index difference on the thermal effect of GG-ICG fiber laser is discussed. This paper provides a theoretical reference for optimizing GG-ICG fiber laser. Based on phosphate glass, the fabrication scheme of the core and cladding of the Nd3 GG-ICG doped fiber is designed, and the fabrication process of the glass is discussed. The influence of individual components on refractive index of glass formulation was studied. Finally, the core and cladding glass were obtained by adjusting the formula, which made the refractive index curve of the core and cladding reach the distribution law in the theoretical model. The refractive index and thermal transition temperature (TG) were measured, and the possibility of pulling GG-ICG fiber was discussed. At the same time, the optical properties of the laser glass were tested, and a series of performance indexes were obtained, which provided the experimental basis for the subsequent drawing fiber.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN253

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