窄线宽连续光纤激光倍频特性研究
文献类型：学位论文
| 作者 | 焦梦丽 |
| 学位类别 | 硕士 |
| 答辩日期 | 2012 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 周军 |
| 关键词 | 光纤放大器 窄线宽 倍频 准相位匹配 |
| 其他题名 | Study on the second harmonic generation of the continuous wave narrow-linewidth fiber laser |
| 中文摘要 | 窄线宽高功率光纤激光器和光纤放大器在效率、体积、光束质量等方面优势明显，将窄线宽光纤激光与倍频技术相结合获得绿光激光输出，近年来已引起人们的广泛兴趣。光纤激光倍频得到的绿光激光在激光显示、激光微加工、激光医疗等领域有着十分广阔的应用前景。本文首先对窄线宽激光的光纤放大特性进行了研究，设计并研制了10W量级和40W量级的窄线宽连续保偏光纤放大器，并对大模场保偏掺镱光纤的偏振保持特性进行了探索和分析。然后以所研制的窄线宽光纤放大器为基频光源，采用周期极化钽酸锂（PPSLT）晶体为倍频晶体，进行了光纤激光的单通倍频特性的理论和实验研究。论文主要内容如下： 第一章介绍了光纤激光器和窄线宽光纤激光器及放大器的产生与发展。并对国内外采用内腔、外腔谐振倍频，及腔外单通倍频方式倍频光纤激光的研究进展进行了综述。 第二章主要研究了窄线宽激光的光纤放大特性，首先采用种子源主振荡放大(MOPA)的两级级联光纤结构，实现了10W量级的窄线宽连续光纤激光输出，光束质量因子M²＜1.1。以大模场掺镱保偏双包层光纤为增益介质，采用三级级联光纤放大结构实现了40W量级的连续光纤激光输出。实验研究了光纤熔接、光纤缠绕对保偏光纤放大器偏振输出特性的影响。对于大模场保偏双包层光纤，光纤缠绕模式控制技术虽然可实现高光束质量、高偏振消光比的放大激光输出，但偏振起伏较大。从扭转力和温度变化对两个特征方向偏振耦合影响的角度，对偏振起伏特性进行了解释和分析。 第三章针对光纤激光的准相位匹配频率转换，分析了晶体温度、激光线宽、光束聚焦因子对倍频转换效率的影响，以国产PPSLT晶体为倍频器件，以所研制的窄线宽（FWHM＜0.035nm）连续波保偏光纤激光放大器为基频光源，进行了光纤激光的PPSLT单通倍频实验研究。在基频光21.5W时得到了2.1W的绿光激光输出，倍频效率9.77%。将光纤放大器的种子光源换用线宽为20kHz的单频种子源，在注入基频光功率15W时，获得了10%的倍频效率。 |
| 英文摘要 | The narrow-linewidth high-power fiber laser and amplifier have excellent performance in efficiency, volume, beam quality and so on. The combination of the narrow-linewidth fiber laser and the frequency-doubling technology can produce high quality green laser, which has a variety of application fields such as laser display, industrial micromachining, laser medical treatment and so on. This technology has attracted extensive attention in recent years. In this dissertation, fiber amplifying characters of the narrow-linewidth laser is studied at first. 10W and 40W level narrow-linewidth Continuous Wave(CW), Polarization Maintaining(PM) fiber amplifiers are designed. Then the PM characteristic of Yb-doped Large Mode Area(LMA) fiber is analyzed. Single-pass Second Harmonic Generation(SHG) of the developed narrow-linewidth fiber laser based on PPSLT is is researched theoretically and experimentally. The main contents are as follows: In the first chapter, the generation and development of the fiber laser, narrow-linewidth fiber laser and amplifier are presented. The progress of the SHG of the fiber laser based on the technique of intracavity, external resonant cavity, and single-pass second harmonic generation scheme at home and abroad is overviewed In the second chapter, fiber amplification characteristic of the narrow-linewidth laser is mainly researched. the scheme of 10W level, narrow-linewidth CW fiber laser is achieved with the use of MOPA technique in two-stage amplified modules. The measured beam propagation factor M² is less than 1.1. With the Yb-doped double-clad LMA fiber as the gain medium, 40W narrow-linewidth CW fiber laser is realized with the application of three-stage fiber amplified modules. The effects of the fiber welding quality and fiber bending on the polarization are researched. The result shows that as for double-clad LMA-PM fiber, higher PER and beam quality of the amplified laser can be achieved by the mode control technology through fiber bending, but the fluctuation of the polarization is also higher. The polarization unstability is explained in polarizing coupling of different directions caused by the twisting force and temperature. In the third chapter, effects on the SHG efficiency by the crystal temperature, laser linewidth and focusing parameter are analyzed via QPM frequency doubling of fiber laser. Single-pass SHG of the developed narrow-linewidth (FWHM＜0.035nm)CW, PM fiber laser based on domestic PPSLT is implemented. 2.1 W green light is achieved at the pump fundamental power of 21.5 W, with the efficiency of 9.77%. At last, when we use a single frequency of 20kHz as the amplifier seed, the second harmonic conversion efficiency of 10% is achieved with respect to the input power of 15W. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16722]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 焦梦丽. 窄线宽连续光纤激光倍频特性研究[D]. 中国科学院上海光学精密机械研究所. 2012. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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