高功率窄线宽光纤激光研究及其工程化

发布时间：2018-11-09 08:54

【摘要】：光纤激光器相比于传统固体激光具有光束质量好、转化效率高、结构紧凑及稳定性高等优点,可广泛应用于光纤通信、医学治疗、激光雷达、激光倍频、光束相干合成等众多领域。高功率、窄线宽光纤激光器是目前光纤激光器研究的主要目标和热点之一。受激布里渊散射(SBS)是光纤中一种非常重要的非线性效应,对于单频光纤激光器来说,SBS效应的低阈值限制了窄线宽光纤激光器的功率提升,如何有效抑制SBS效应是提高窄线宽光纤激光器功率的难点。本文首先设计并搭建一套中心波长分别为1064 nm和1030 nm的两级主振荡功率放大(MOPA)全光纤激光系统,分析和研究了SBS效应对两种不同波长单频种子源功率放大的影响,同时对不同波长的单频激光器在放大过程中的差异性进行对比研究。结果发现当两者输出光功率分别大于20.4 W和21.2 W时,均出现较为严重的SBS,表明想获得更高功率的输出,必需采取有效措施对SBS效应进行抑制,防止反向散射光功率急剧增加。其次,以白噪声作为射频信号源,采用相位调制技术,设计并搭建了一套三级MOPA全光纤激光系统,分析和研究了信号光频谱宽度与光纤放大器系统SBS阈值之间的关系,通过改变白噪声信号的幅值,实现精确控制信号光谱宽,获得了中心波长为1030.60 nm、线宽为0.9 GHz、平均功率为75 W的窄线宽准连续近衍射极限激光输出,相应的X方向与Y方向的光束质量因子分别为M2X=1.23,M2Y=1.24。最后,本文对基于白噪声相位调制的全光纤激光放大器进行电学、机械及热管理等系统设计,初步完成了一台高功率、窄线宽全光纤激光放大器工程化样机的制作,并进行了工程化测试,获得了中心波长为1030.60 nm、谱宽为0.9 GHz、平均功率为75 W的窄线宽准连续近衍射极限激光输出。本文的研究工作有望为实现更高功率单频窄线宽光纤激光器的产业化提供可靠的理论依据和实验基础。
[Abstract]:Compared with conventional solid-state lasers, fiber lasers have the advantages of good beam quality, high conversion efficiency, compact structure and high stability. They can be widely used in optical fiber communication, medical treatment, lidar, laser frequency doubling, etc. Beam coherent synthesis and many other fields. High power, narrow linewidth fiber laser is one of the main targets and hot spots in fiber laser research. Stimulated Brillouin scattering (SBS) is a very important nonlinear effect in fiber. For a single frequency fiber laser, the low threshold of SBS effect limits the power increase of narrow linewidth fiber laser. How to effectively suppress the SBS effect is a difficult problem to improve the power of narrow linewidth fiber laser. In this paper, a two-stage main oscillator power amplifier (MOPA) all-fiber laser system with central wavelength of 1064 nm and 1030 nm is designed and constructed. The effect of SBS effect on the power amplification of two different wavelength single-frequency seed sources is analyzed and studied. At the same time, the difference in amplification process of single frequency laser with different wavelengths is compared and studied. The results show that when the output optical power is more than 20.4W and 21.2W, both of them have more serious SBS, which indicates that it is necessary to take effective measures to suppress the SBS effect in order to obtain higher output power. Prevent a sharp increase in the power of backscattered light. Secondly, using white noise as radio frequency signal source and phase modulation technology, a three-stage MOPA all-fiber laser system is designed and built. The relationship between signal optical spectrum width and SBS threshold of fiber amplifier system is analyzed and studied. By changing the amplitude of the white noise signal, the spectral width of the signal can be accurately controlled, and the narrow linewidth of the center wavelength of 1030.60 nm, line width of 0.9 GHz, average power of 75 W is obtained, and the narrow linewidth quasi-continuous near-diffraction limit laser output is obtained. The corresponding beam quality factors in X direction and Y direction are M2XO 1.23 and M2YN 1.24, respectively. Finally, the electrical, mechanical and thermal management system of all-fiber laser amplifier based on white noise phase modulation is designed, and a prototype of high-power, narrow-linewidth all-fiber laser amplifier is made. The narrow linewidth quasi-continuous near diffraction limit laser output with 1030.60 nm, spectral width of 0.9 GHz, average power of 75 W has been obtained by engineering test. The research work in this paper is expected to provide a reliable theoretical and experimental basis for the industrialization of high-power single-frequency narrow linewidth fiber lasers.
【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】：TN248

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