高功率连续和调Q脉冲中红外光纤激光器的研究

发布时间：2018-05-12 02:24

本文选题：高功率 + 调Q脉冲　；参考：《电子科技大学》2017年硕士论文

【摘要】：近年来,波长为3μm的高功率光纤激光器因其在激光手术、材料加工、军事对抗以及科研等方面的巨大应用前景,同时相比于其它类型的激光器具有光束质量高、散热性能好、转换效率高、灵活性好等特点,从而激起了海内外科研人员极大的研究兴趣。基于中红外光纤激光器的以上特点,本文着重研究高功率连续和调Q脉冲中红外光纤激光器。主要内容可以分为以下几个部分:(1)基于高浓度掺Er~(3+)ZBLAN光纤中铒离子的能级跃迁过程,建立了表示各能级粒子数密度变化的速率方程和表征功率随时间和空间变化的功率传输方程,同时结合谐振腔边界条件构建了高浓度掺Er~(3+)ZBLAN光纤激光器系统模型。通过综合考虑激光斜率效率、阈值泵浦功率和光纤产热等随谐振腔参数及泵浦源参数的变化,我们对光纤长度、掺杂浓度、输出反射率和泵浦波长等因素进行了优化。(2)利用4.1m长的高浓度掺Er~(3+)ZBLAN光纤作为增益光纤,搭建了高功率掺Er~(3+)ZBLAN光纤激光器,并研究了其输出特性。最终,实现了最大功率为7.11W,中心波长为2802nm的连续激光输出,对应最大功率波动范围为4.3%,斜率效率为36.06%,已经超过34.3%的斯托克斯极限。(3)首先,我们搭建了基于SESAM可饱和吸收体的被动调Q掺Er~(3+)ZBLAN光纤激光器,并得到了稳定的调Q脉冲。研究分析了对应不同泵浦功率的调Q脉冲输出特性,得到了最大脉冲能量为3.52μJ,平均功率为0.252W,脉宽为1.7μs,重复频率为71.43kHz,中心波长为2786.8nm的稳定调Q脉冲激光。而后,我们搭建了基于高浓度掺Er~(3+)ZBLAN光纤的主振荡功率放大(Master Oscillator Power Amplifier,简称MOPA)系统,将前面得到的稳定调Q脉冲作为种子源注入MOPA系统,研究了MOPA系统中不同光纤端面切角下输出脉冲的放大特性,最终得到了最大平均功率和脉冲能量分别为4.2W和58.87μJ的放大脉冲输出,对应脉冲宽度为2.29μs,重复频率为71.73kHz,光谱的中心波长为2786.8nm,MOPA系统的斜率效率为30.79%。
[Abstract]:In recent years, high power fiber lasers with wavelength of 3 渭 m have great application prospects in laser surgery, material processing, military confrontation and scientific research, at the same time, compared with other types of lasers, they have high beam quality and good heat dissipation performance. The characteristics of high conversion efficiency and good flexibility have aroused great interest of researchers at home and abroad. Based on the above characteristics of mid-infrared fiber laser, this paper focuses on the study of high power CW and Q-switched pulse mid-infrared fiber laser. The main contents can be divided into the following parts: 1) based on the energy level transition process of erbium ion in high concentration doped Er~(3 fiber, The rate equation representing the change of particle number density of each energy level and the power transmission equation representing the change of power with time and space are established. The system model of high concentration Er~(3 doped ZBLAN-based fiber laser is constructed in combination with the resonator boundary condition. By considering the variation of laser slope efficiency, threshold pump power and optical fiber heat production with the parameters of resonator and pump source, the length of fiber and the concentration of doped fiber are studied. The output reflectivity and pump wavelength were optimized. (2) High power Er~(3 doped ZBLAN-based fiber laser was constructed using 4.1m long high concentration Er~(3 doped ZBLAN-based fiber as gain fiber, and its output characteristics were studied. Finally, a continuous laser output with a maximum power of 7.11W and a center wavelength of 2802nm is achieved, corresponding to the maximum power fluctuation range of 4.3, the slope efficiency of 36.06, which has exceeded the Stokes limit of 34.3%. A passive Q-switched Er~(3 doped ZBLAN-based fiber laser based on SESAM saturable absorber is constructed and stable Q-switched pulses are obtained. The characteristics of Q-switched pulse with different pump power are studied and analyzed. A stable Q-switched laser with maximum pulse energy of 3.52 渭 J, average power of 0.252 W, pulse width of 1.7 渭 s, repetition rate of 71.43 kHz and center wavelength of 2786.8nm is obtained. Then, a master power amplifier master Oscillator Power Amplifier, system based on high concentration Er~(3 doped ZBLAN fiber is built, and the stable Q-switched pulse is injected into the MOPA system as a seed source. The amplification characteristics of output pulses at different fiber end tangent angles in MOPA system are studied. The maximum average power and pulse energy are 4.2W and 58.87 渭 J, respectively. The corresponding pulse width is 2.29 渭 s, the repetition rate is 71.73 kHz, and the central wavelength of the spectrum is 2786.8 nm. The slope efficiency of MOPA system is 30.79.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

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