Yb掺杂石英玻璃及大模场光纤的制备
文献类型：学位论文
| 作者 | 刘双 |
| 学位类别 | 博士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈丹平 |
| 关键词 | 纳米孔玻璃粉烧结法，大模场石英光子晶体光纤，激光性质，石英玻璃中的点缺陷，闪烁发光性能 |
| 其他题名 | Study on Preparation and Properties of Yb-doped Silica Glass and Large Mode Area Fiber |
| 中文摘要 | 随着光纤激光器输出功率的不断提高，高功率激光光纤的制备在工艺上要求更大尺寸的芯棒和对稀土掺杂光纤预制棒折射率分布更精确的控制。然而，多数现有的稀土掺杂石英光纤预制棒制备工艺是在通信光纤制备工艺的基础上发展而来的，其局限性逐步显现，因而迫切需要开发制备高功率激光光纤预制棒的新工艺。另一方面，关于稀土掺杂石英玻璃缺陷的研究也十分重要，尤其是对理解光纤的光致暗化现象而言。 本文包括七个部分：文献综述、实验过程及方法、稀土掺杂石英玻璃及大模场光纤的制备和性能、掺镱石英玻璃的X射线辐照行为研究、X射线辐致暗化掺镱石英玻璃的热漂白行为研究、Yb2+离子掺杂石英玻璃的X射线闪烁发光性能研究、总结与展望。 文献综述部分首先介绍了稀土掺杂光纤的发展过程和稀土掺杂石英玻璃光纤预制棒的制备工艺。本课题在我们研究小组制备多孔玻璃的技术积累的基础上，提出了多孔玻璃粉烧结法制备稀土掺杂石英玻璃光纤预制棒的工艺。本章对多孔玻璃，尤其是多孔玻璃在发光和激光材料制备方面的应用进行了介绍。为了方便对正文内容的理解，文献综述还介绍了石英玻璃中常见缺陷的结构和光谱性能。 实验过程及方法部分叙述了Yb3+离子掺杂石英玻璃和光纤的制备过程、玻璃和光纤性能的测试方法。 第三章研究了稀土掺杂石英玻璃及大模场光纤的制备和性能。通过对纳米孔多孔玻璃粉烧结工艺的探索和优化，制备了掺镱石英玻璃。Yb/Al掺杂石英玻璃在976 nm处的吸收截面为1.04 pm2，在1020 nm处的荧光发射截面为0.72 pm2，羟基含量为59 ppm，896 nm脉冲氙灯激发下的荧光寿命为775 μs。对制备的单包层光纤进行了折射率分布测试，芯层和包层的折射率差为1.7×10-3，折射率波动为2.8275×10-4，在1200 nm处的背景损耗为1.10 dB/m。对制备的大模场光子晶体光纤进行了激光性能测试，获得的最高激光输出功率为34.8 W，斜率效率为71.3%，输出激光束的平均M2为2.42。 第四章研究了掺镱石英玻璃的X射线辐照行为。通过对多孔玻璃粉烧结法制备稀土掺杂石英玻璃工艺的调控，制备了含有低、中、高含量羟基的掺镱石英玻璃样品。利用吸收光谱、辐致吸收光谱、红外透过光谱和电子顺磁共振波谱，对X射线辐照前后各样品的性能进行了表征。结果表明，高含量羟基掺镱石英玻璃样品表现出较好的抗辐照性能。这是因为羟基在X射线作用下发生辐致分解得到的自由H原子与辐致缺陷结合，减弱了X射线辐致暗化程度。 第五章研究了X射线辐致暗化掺镱石英玻璃的热漂白行为。所有X射线辐致暗化掺镱石英玻璃经过450~500℃热处理后均被完全漂白。对各类型辐致缺陷中心的热漂白行为的进一步研究表明，E’心、Al-E’心和ODC(II)缺陷的热漂白行为较复杂，且在不同样品中差异较大；Al-OHC和NBOHC缺陷的热漂白行为则较简单和有规律。这一区别可以通过各缺陷中心在石英玻璃材料能带结构中引入的能级的位置的不同来解释：E’心、Al-E’心和ODC(II)缺陷的能级距离石英玻璃材料的导带底较近，属于深能级缺陷；Al-OHC和NBOHC缺陷的能级距离石英玻璃材料的价带顶较近，属于浅能级缺陷。 第六章研究了Yb2+离子掺杂石英玻璃的闪烁发光性能。与常用作闪烁发光材料激活离子的Ce3+类似，Yb2+离子同样具有5d-4f辐射跃迁。5d-4f跃迁过程为跃迁选律所允许，一般具有荧光强度强、荧光寿命短等特点。采用还原气氛烧结，通过多孔玻璃粉烧结法制备了Yb2+离子掺杂石英玻璃。Yb2+离子在330 nm存在吸收带，在510 nm存在发射带，荧光寿命为53 μs。X射线激发荧光光谱结果表明，Yb2+离子掺杂石英玻璃存在525 nm的闪烁发光带。本章还对Yb2+离子与ODC(II)缺陷中心之间的能量传递过程进行了研究。没有Yb2+存在的情况下，ODC(II)缺陷的荧光寿命为107.77 μs（慢光成分）和10.27 μs（快光成分）；有Yb2+共存时，ODC(II)缺陷中心的荧光寿命分别缩短为72.04 μs（慢光成分）和8.85 μs（快光成分）。这表明Yb2+离子掺杂石英玻璃中存在从ODC(II)缺陷中心向Yb2+离子的共振能量传递过程。 文章最后对本课题工作进行了回顾，总结了本课题的主要创新点，指出了本课题的不足，并给出了下一步研究的建议。 |
| 英文摘要 | With increasing output power of fiber lasers, the fabrication of high power laser fiber requires larger sized core rod and more precise control of the refractive index profile of rare earth doped fiber preforms. However, most of the existing preparation techniques of rare earth doped silica fiber preforms are based on the processes which were used to produce communication fibers and their limitations have gradually emerged. Therefore, it is urgent to develop new techniques to fabricate high power laser fiber preforms. On the other hand, study on the defects in rare earth doped silica glass is very important to understand photodarkening phenomenon in rare earth doped silica fibers. This dissertation consists of the following seven sections: literature review, experimental processes and methods, fabrication and properties of rare earth doped silica glass and large mode area fibers, research on behaviors of Yb-doped silica glass under X-ray irradiation, research on behaviors of thermal bleaching of Yb-doped silica glass pre-darkened by X-ray irradiation, luminescence and scintillation properties of Yb2+-doped silica glass, and the conclusion and outlook. The literature review part first deals with the development history of rare earth doped fiber and the fabrication techniques of rare earth doped silica glass fiber preform. Based on our research group’s experience on fabrication of porous silica glass, this work proposes nanoporous glass powder sintering technique for the preparation of rare earth doped silica glass fiber preform. This chapter gives an introduction of porous glass focusing on the application of porous glass in luminescent and laser materials fields. In order to gain an understanding of the main context of this dissertation, this chapter also reviews the structure and optical properties of common point defects in silica glass. The experimental section describes the fabrication process of Yb3+-doped silica glass and the fibers and the methods used for measuring their properties. Chapter III presents the fabrication of rare earth doped silica glass and large mode area fibers as well as their properties and performances. Through exploration and optimization of the fabrication processes of nanoporous glass powder sintering technique, Yb/Al-codoped silica glass is prepared. The maximum absorption and emission cross sections of the prepared Yb/Al-codoped silica glass are 1.04 pm2 at 976 nm and 0.72 pm2 at 1020 nm, respectively. The content of hydroxyl is 59 ppm. The fluorescence lifetime is 775 μs under excitation of pulsed Xe light of 896 nm. Refractive index difference between the core and the cladding of the single-cladding fiber is 1.7×10-3, the deviation of the refractive index is 2.8275×10-4. The background loss is 1.10 dB/m at 1200 nm. Up to 34.8 W laser output at 1048 nm is obtained from the prepared large mode area photonic crystal fiber. The slope efficiency is 71.3%. The average M2 factor of the output laser beam is 2.42. Chapter IV presents the research on behaviors of Yb-doped silica glass under X-ray irradiation. Yb-doped silica glasses with low-, medium- and high-content OH are prepared through tailoring the fabrication processes of nanoporous glass powder sintering technique. Optical absorption, radiation-induced absorption, Fourier transformed infrared spectra and electron spin resonance spectra are used to characterize the properties of samples before and after X-ray irradiation. The results suggest that Yb-doped silica glass with high-content OH exhibits better radiation hardness. This is due to the annihilation effects of free hydrogen atoms resulting from the radiolytic process of hydroxyls. Chapter V presents the research on behaviors of thermal bleaching of Yb-doped silica glass pre-darkened by X-ray irradiation. All radiation-induced darkening is thoroughly bleached after heat treatments under 450~500℃. Investigation into the thermal bleaching behaviors of various defect types reveal that the behaviors of E’ center, Al-E’ center and ODC(II) are complex while the behaviors of Al-OHC and NBOHC are simpler and regular. This difference between the two groups of defects are explained by their different energy levels in the bandgap of silica glass materials: the energy levels of E’ center, Al-E’ center and ODC(II) are close to the bottom of the conduction band whereas the energy levels of Al-OHC and NBOHC are close to the top of the valence band. As a result, the former group belongs to deep energy level defects and the latter group is shallow energy level defects. Chapter VI presents luminescence and scintillation properties of Yb2+-doped silica glass. Similar with the most commonly used scintillation activator, Ce3+ ion, Yb2+ ion also gives 5d-4f transition which is allowed by the selection rule resulting in features of high fluorescence intensity and short lifetime. By using reducing sintering atmosphere, Yb2+-doped silica glass is prepared through nanoporous glass powder sintering technique. The absorption and emission bands of Yb2+ ions are 330 nm and 510 nm, respectively. The fluorescence lifetime of Yb2+ ions in silica glass is 53 μs. Scintillation band at 525 nm of Yb2+-doped silica glass is demonstrated under excitation of X-ray. The energy transfer process between ODC(II) and Yb2+ ions is also revealed. After the incorporation of Yb2+ ions, the fluorescence lifetimes of ODC(II) become 8.85 μs (fast component) and 72.04 μs (slow component) from the initial values of 10.27 μs and 107.77 μs. This shortening evidences the F?rster resonant energy transfer process between ODC(II) and Yb2+ ions. In the last section, conclusions and highlights of this work are outlined. The shortages of this work are also given as well as the suggestions concerning further researches. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15921]  |
| 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 | 刘双. Yb掺杂石英玻璃及大模场光纤的制备[D]. 中国科学院上海光学精密机械研究所. 2015. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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