掺钕大模场双包层光子晶体光纤激光器的特性研究

发布时间：2018-06-03 03:25

本文选题：光纤激光器 + 掺Nd~(3+)光子晶体光纤　；参考：《济南大学》2017年硕士论文

【摘要】：钕离子(Nd~(3+))是最早用于激光器的三价稀土离子,可采用激光二极管(LD)泵浦,已在上百种不同基质材料中获得了受激发射,在军事、工业、生物、医疗和科学研究等领域有广泛应用。掺Nd~(3+)光纤激光器具有结构紧凑、稳定性高、抗干扰性好、光束质量高等优势,一直是科学领域的研究热点之一。目前,普通单模掺Nd~(3+)光纤激光器的输出功率大多在毫瓦量级。普通双包层掺Nd~(3+)光纤激光器虽然可以实现高功率激光输出,但容易产生多模运转,导致光束质量下降。这种缺陷可以在光子晶体光纤中通过合理的结构设计予以消除,同时发挥大模场面积、无截止单模特性两方面的优势。本论文基于掺Nd~(3+)大模场双包层保偏光子晶体光纤,研究获得1.06μm波段高功率、高光束质量连续波激光以及高能量锁模脉冲激光的方法和途径。主要研究内容如下:1.研究了掺Nd~(3+)大模场双包层保偏光子晶体光纤的光谱特性,并根据光纤包层中的空气孔的大小及周期间隔等参数,分析了掺Nd~(3+)光子晶体光纤的模式特性、色散特性、偏振特性、非线性效应和损耗特性,为激光器设计提供了依据和指导。2.研究了LD抽运掺Nd~(3+)大模场双包层保偏光子晶体光纤的连续波激光特性,最大输出功率为5.95W,光束质量M2因子小于1.30,偏振串音为-7.9dB,这表明掺Nd~(3+)大模场双包层保偏光子晶体光纤具有良好的单模传输特性和保偏特性,有利于激光器实现高功率高光束质量的激光输出。3.基于全正色散腔,研究了掺Nd~(3+)大模场双包层保偏光子晶体光纤的锁模激光特性。采用半导体可饱和吸收镜(SESAM)锁模元件,在腔内不加任何色散补偿元件的情况下,实现了1μm波段锁模激光运转,脉冲宽度为73.1ps,最大平均输出功率为236.8mW,对应的单脉冲能量为17.3nJ。这表明掺Nd~(3+)大模场双包层保偏光子晶体光纤可以有效较低非线性效应,有利于获得高能量的锁模脉冲激光输出。4.设计了基于掺Nd~(3+)大模场双包层保偏光子晶体光纤的激光放大器,采用自搭建Nd:YVO4晶体连续波激光器提供种子源,实现了连续波激光放大,最大输出功率为8.75W。本论文有关掺Nd~(3+)保偏光子晶体光纤高功率连续波激光、锁模脉冲激光以及激光放大的研究结论,对该领域研究工作的进一步开展具有很好的参考价值和推动作用。
[Abstract]:Neodymium (ND) is the first trivalent rare earth ion used in lasers. It can be pumped by laser diode (LD). It has been stimulated in hundreds of different matrix materials, and has been used in military, industrial and biological fields. Medical and scientific research and other fields have a wide range of applications. Fiber laser doped with Nd~(3 has many advantages such as compact structure, high stability, good anti-jamming and high beam quality, so it has been one of the research hotspots in the field of science. At present, the output power of ordinary single mode doped Nd~(3) fiber laser is mostly in milliwatt order. Although the conventional double-clad Nd~(3) fiber laser can achieve high power laser output, it is easy to produce multi-mode operation, which leads to the deterioration of beam quality. This defect can be eliminated by reasonable structure design in photonic crystal fiber, and the advantages of large mode field area and no cut-off single mode characteristic can be taken into account at the same time. In this paper, the method and approach of 1.06 渭 m high power, high beam quality CW laser and high energy mode-locked pulse laser are studied based on the large mode field dual-clad photonic crystal fiber doped with Nd~(3. The main research contents are as follows: 1. In this paper, the spectral characteristics of Nd~(3) large mode field double cladding polarization-maintaining photonic crystal fiber are studied. Based on the parameters such as air hole size and periodic interval in the fiber cladding, the mode characteristics and dispersion characteristics of Nd~(3 doped photonic crystal fiber are analyzed. Polarization characteristics, nonlinear effects and loss characteristics provide basis and guidance for laser design. The CW laser characteristics of LD pumped Nd~(3 doped large mode double cladding polarization-maintaining photonic crystal fiber are studied. The maximum output power is 5.95 W, the beam quality M2 factor is less than 1.30, and the polarization crosstalk is -7.9 dB, which indicates that the dual-clad polarization-maintaining photonic crystal fiber doped with Nd~(3) has good single-mode propagation and polarization-maintaining characteristics. The laser output of high power and high beam quality is favorable to laser output. 3. Based on the fully positive dispersion cavity, the mode-locked laser characteristics of a large-mode dual-cladding polarization-maintaining photonic crystal fiber doped with Nd~(3 are studied. A 1 渭 m band mode-locked laser with a pulse width of 73.1 pss. maximum average output power of 236.8 MW and a corresponding single pulse energy of 17.3 nJ have been realized by using a semiconductor saturable absorption mirror SESAM mode-locking element without adding any dispersion compensation elements in the cavity. The results show that the large mode field double cladding photonic crystal fiber doped with Nd~(3 can effectively reduce the nonlinear effect and is advantageous to obtain high energy mode-locked pulse laser output .4. A laser amplifier based on large mode field double cladding photonic crystal fiber is designed. The self-constructed Nd:YVO4 crystal CW laser is used to provide seed source and the maximum output power is 8.75 W. In this paper, the research results of high power CW laser, mode-locked pulse laser and laser amplification of Nd~(3 doped photonic crystal fiber have good reference value and impetus for further research work in this field.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

【参考文献】