高能量主动调QZBLAN脉冲光纤激光器的理论和实验研究

发布时间：2018-04-10 20:24

本文选题：中红外光纤激光器 + 主动调Q　；参考：《电子科技大学》2017年硕士论文

【摘要】：中红外激光器一直是激光研究领域的热点,在国防、生物医学、大气环境监测等领域具有广阔的应用前景。中红外光纤激光器是近几年发展起来的新技术,与传统的固体和气体激光器相比,具有光束质量好、散热性好、转换效率高、结构简单等诸多优点。与连续输出的光纤激光器相比,调Q脉冲光纤激光器可以在不太高的平均功率下获得更高的峰值功率和脉冲能量,因此发展中红外调Q脉冲光纤激光器在工业加工、激光医疗、和光电对抗等领域具有更为重要的应用价值。目前,国内外已有大量关于中红外调Q脉冲光纤激光器的实验报道,但相关理论研究的报导却较少。因此本文工作主要如下:1.建立了基于高浓度掺Er3+ZBLAN光纤的主动调Q光纤激光器和低浓度掺Ho3+ZBLAN级联光纤的主动调Q光纤激光器的理论数值模型,模拟分析了纤芯半径,泵浦功率,重复频率,光纤损耗,光纤长度,声光效率等对调Q脉冲输出特性的影响。结果表明对高浓度掺Er3+光纤采取前向泵浦方式,对低浓度掺Ho3+光纤采取双向泵浦方式会引起各自脉冲能量,峰值功率和存储能量上升,脉冲宽度减小;提高泵浦功率或减小重复频率能输出更高能量,更窄脉宽,更高峰值功率的脉冲并增加光纤存储能量;光纤纤芯半径较大会引起脉冲能量,脉冲宽度和存储能量上升,峰值功率下降;光纤长度过长会引起脉冲能量下降,脉冲宽度上升和脉冲建立时间的增加;光纤激光器内的损耗(AOM损耗,光纤损耗,输出耦合损耗)都会引起输出能量和峰值功率下降,但对脉冲宽度没有影响。2.通过理论优化设计,首先搭建了主动调Q掺Ho3+ZBLAN级联光纤激光器,实现了高能量、高功率的双波段3μm和2μm的脉冲稳定激光输出。其中3μm波段脉冲激光在重复频率25kHz处得到最高峰值功率为78W,最大脉冲能量29.8μJ,而2μm波段脉冲在重复频率17kHz处得到最高峰值功率49W,最大脉冲能量9.2μJ。其次,搭建了主动调Q导引增益调制脉冲光纤激光器,通过对平面光栅的调节实现了波长调谐范围在2.95μm到3.031μm的5I6→5I7跃迁的脉冲激光输出和2μm波段的稳定脉冲增益调制输出。当重复频率为40kHz时,得到了最大脉冲能量17μJ,最大峰值功率43W,脉冲宽度410ns的3μm波段脉冲激光输出,对应的2μm波段脉冲的最大脉冲能量为3.7μJ,脉冲宽度为550ns,并且输出波长基本不变。
[Abstract]:The mid-infrared laser has been a hot spot in the field of laser research, and has a broad application prospect in the fields of national defense, biomedicine, atmospheric environment monitoring and so on.The mid-infrared fiber laser is a new technology developed in recent years. Compared with conventional solid-state and gas lasers, it has many advantages, such as better beam quality, better heat dissipation, higher conversion efficiency and simpler structure.Compared with continuous output fiber laser, Q-switched pulse fiber laser can obtain higher peak power and pulse energy at low average power, so developing infrared Q-switched pulse fiber laser is in industrial processing, laser medical treatment,And optoelectronic countermeasures and other fields have more important application value.At present, there have been a lot of experimental reports about the external Q-switched pulse fiber lasers, but there are few reports on the related theoretical studies.Therefore, the main work of this paper is as follows: 1.The theoretical numerical models of the active Q-switched fiber laser based on high concentration Er3 ZBLAN fiber and the low concentration Ho3 ZBLAN cascade fiber are established. The core radius, pump power, repetition rate and fiber loss are simulated and analyzed.The effects of fiber length and acoustooptic efficiency on the output characteristics of Q-switched pulses.The results show that using forward pumping mode for high concentration Er3 doped fiber and bidirectional pumping mode for low concentration Ho3 doped fiber will lead to the increase of pulse energy peak power and storage energy and decrease of pulse width.Increasing pump power or reducing repetition rate can output higher energy, narrower pulse width, higher peak power and increase storage energy of fiber. Larger radius of fiber core will cause pulse energy, pulse width and storage energy increase.The peak power is decreased, the length of the fiber is too long, the pulse energy will decrease, the pulse width will rise and the pulse establishment time will be increased, the loss of AOM in fiber laser, the loss of fiber, the loss of fiber, the loss of AOM in fiber laser,The output coupling loss) will cause the output energy and peak power to decrease, but has no effect on the pulse width.Through the theoretical optimization design, the active Q-switched Ho3 ZBLAN cascaded fiber laser is first built, and the pulse stabilized laser output of 3 渭 m and 2 渭 m is realized with high energy and high power.The maximum peak power of 3 渭 m band pulse laser is 78 W and the maximum pulse energy is 29.8 渭 J at the repetition rate 25kHz, while the maximum peak power is 49 W and the maximum pulse energy is 9.2 渭 J. at the repetition rate 17kHz at 2 渭 m band, the maximum peak power of the laser is 78 W and the maximum pulse energy is 29.8 渭 J.Secondly, an active Q-switched guided gain modulated pulsed fiber laser is built. By adjusting the plane grating, the wavelength tuning range from 2.95 渭 m to 3.031 渭 m 5I6 5I7 transition pulse laser output and 2 渭 m band stable pulse gain modulation output are achieved.When the repetition rate is 40kHz, the maximum pulse energy is 17 渭 J, the maximum peak power is 43 W, the pulse width is 3 渭 m band laser output of 410ns, the maximum pulse energy of 2 渭 m band pulse is 3.7 渭 J, the pulse width is 550 ns, and the output wavelength is almost unchanged.
【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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