| 题名 | 稀土掺杂氟磷玻璃的光谱性质 |
| 作者 | 廖梅松 |
| 学位类别 | 博士 |
| 答辩日期 | 2007 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 胡丽丽 |
| 关键词 | 稀土离子 氟磷玻璃 宽带放大 上转换发光 |
| 其他题名 | Spectroscopic properties of rare earth doped fluorophosphate glass |
| 中文摘要 | 随着计算机网络及其它数据传输业务地飞速发展，人们对波分复用系统传输容量的需求日益增长。现有的稀土掺杂光纤放大器已难于应对未来光纤通信系统扩容的挑战。因此，必须研究新的稀土掺杂宽带放大材料。对石英光纤第三通信窗口的C波段，现阶段广泛应用的掺铒光纤放大器材料为石英基质，其存在的主要问题是放大带宽过窄、增益谱线不平坦、铒离子掺杂浓度过低。对于S波段，现有的掺铥光纤放大器材料为氟锆玻璃基质，其主要问题是制备困难、物化稳定性差、机械强度低。氟磷玻璃兼具有氟化物玻璃和磷酸盐玻璃的优点，其荧光光谱宽而平坦，荧光寿命长，脱OH基团能力比磷酸盐玻璃强，在机械强度、成玻璃性能等方面比氟化物玻璃具有优势。目前关于氟磷玻璃用作光纤放大器材料的研究，国际上已有少量文献报导，但远未达到系统和完善。本论文选取掺铒和掺铥氟磷玻璃的光谱性质作为研究对象，探讨了氟磷玻璃作为掺铒光纤放大器和掺铥光纤放大器基质材料的可行性。 随着信息处理、数据存储、水下通信、视频显示及表面处理等技术的迅速发展，越来越需要高效率、低价格、高性能的可见光波长的激光光源。上转换光纤激光器具有输出波长多、适宜于LD泵浦、可调谐、结构简单等优点，越来越受到重视。关于可见光波段上段换激光器玻璃材料的研制，已成为近年来的研究热点。现有的上转换光纤激光器材料主要是氟化物玻璃材料，存在着光纤损耗较大、机械强度差、制备工艺复杂等问题。研究新的上转换玻璃材料也具有重要意义。本论文也研究了低磷酸盐含量的氟磷玻璃的上转换光谱性质，力求获得适用于上转换光纤激光器的氟磷玻璃材料。 论文第一章介绍了光纤放大器及其基质材料、上转换发光材料和氟磷玻璃的研究进展，提出了研究目的和计划。第二章介绍了实验要点、主要测试手段和理论分析方法。第三、四、五章为本论文的核心部分。 论文第三章讨论了氟磷玻璃的组成、结构和析晶稳定性之间的关系。对于成分主要为碱金属、碱土金属、氟化铝和偏磷酸铝的氟磷玻璃，通过改变碱金属和碱土金属氟化物的相对含量和种类，可有效调整玻璃的密度和析晶稳定性。当碱金属氟化物和碱土金属氟化物的摩尔百分含量相同时，玻璃的析晶稳定性最佳。在一价碱金属氟化物中，LiF的引入使玻璃的密度明显增加，使析晶稳定性下降。随着碱土金属离子的半径增加，玻璃的密度增加。与含其它碱土金属氟化物的玻璃相比，含MgF2的氟磷玻璃具有相对较好的析晶稳定性。CaF2含量的增加，可以降低玻璃的特征温度，但也会引起析晶稳定性的下降。碱金属氟化物和碱土金属氟化物的种类增加时，玻璃的析晶稳定性增强。红外和拉曼光谱分析表明，析晶稳定性的增强是由于玻璃中的桥氧数目增加，使玻璃的网络结构得以加强。 第四章研究了掺铥氟磷玻璃在S波段的光谱性质和掺铒氟磷玻璃在C波段的光谱性质。对于(60-x)Mg0.17Ca0.49Sr0.17Ba0.17F2-40AlF3-xAl(PO3)3-0.05Tm2O3体系的氟磷玻璃，Al(PO3)3含量的增加不会影响最大声子能量，但使最大能量声子态密度增大。当偏磷酸铝的含量不大于7mol%时，引入偏磷酸铝可改善玻璃析晶稳定性，且不会对光谱性质带来明显负面影响。对于(60-x)Mg0.17Ca0.49Sr0.17Ba0.17F2-40AlF3-xAl(PO3)3-0.8ErF3-2.4YbF3体系的氟磷玻璃，引入适量氟化钠和氟化铅可显著降低玻璃的特征温度、改善其析晶稳定性。随着NaF含量的增加，玻璃的最大声子能量基本不发生变化，但其声子态密度有所增加，玻璃的受激发射截面和荧光半高宽降低。随着PbF2含量的增加，最大声子能量略有降低，玻璃的受激发射截面增加，增益性能有所改善。就受激发射截面和带宽性能而言，该系列氟磷玻璃接近于碲酸盐玻璃，与锗酸盐玻璃和硅酸盐玻璃相比具有明显优势。采用Judd-Ofelt理论分析了镱离子作为一种普通基质组分对铒镱共掺氟磷玻璃中铒离子1530nm波段光谱性质的影响。镱离子作为普通基质组分会使铒离子辐射寿命增加。由于镱离子的敏化，随着镱离子浓度增加，铒离子的荧光寿命存在一个最大值。研究了掺铒氟磷玻璃在C波段的荧光捕获效应。由于荧光捕获效应的影响，不同厚度的样品，其荧光寿命对铒离子浓度呈现出不同的依赖特性。提出了一种基于荧光光谱和吸收光谱定量估算荧光捕获效应对光谱参量影响的方法。制备了配方为：19NaF-7MgF2-21CaF2-5SrF2- 5BaF2- 30AlF3-5YF3-4Al(PO3)3-4ErF3的高铒浓度氟磷玻璃。该玻璃铒离子浓度达到7.45×1020ions/cm3，测量荧光寿命约为8.20ms。其长的荧光寿命得益于其低的OH含量和高的声子能量。 第五章研究了镱铥共掺和铒镱铥共掺氟磷玻璃的上转换光谱性质。在970nm泵浦下，当镱离子的浓度较低的时候，其对铥离子的敏化主要为三光子连续能量转移过程。当镱离子的浓度较高的时候，双光子合作敏化将起重要作用。制备了不同偏磷酸盐含量的铥镱共掺的氟磷玻璃样品。随着偏磷酸盐含量的增加，玻璃的最大能量声子态密度增加，多声子无辐射驰豫增大，上转换发光效率降低。但总体上讲，由于本系列氟磷玻璃的偏磷酸盐含量较低，其上转换蓝光仍较强。制备了铒镱铥共掺的氟磷玻璃，研究了稀土离子浓度对蓝、绿、红上转换发光的影响。调整镱离子的浓度，可以改变上转换发光的强度，并改变蓝光、绿光和红光的强度之比。铥离子对铒离子的上转换绿光和红光具有敏化作用，其敏化效果在很大程度上取决于镱离子的浓度。铒离子对铥离子的上转换蓝光具有淬灭作用。与镱铥共掺的氟磷玻璃中铥离子的淬灭浓度相比，在铒镱铥三掺的氟磷玻璃中，铥离子的淬灭浓度要低。 |
| 英文摘要 | With the rapid development of the computer-network and other data transfer business, people’s demands to the transport capacity of dense wavelength division multiplex system (DWDM) grow day by day. The rare earth doped fiber amplifier available presently will not be able to meet the challenges of capacity expansion of the fiber communication in the near future. As a result it is indispensable to research and develop new rare earth doped material for the fiber amplification. Within the band C of the third communication window of quartz fiber, the host matrix of erbium doped fiber amplifier widely used nowadays is quartz, which exhibits limitations such as: narrow bandwidth of amplification, uneven gain of spectra and low erbium concentration. Within the S band, the host matrix presently available is fluorozirconate glass, which is difficult to manufacture and is expensive. Meanwhile its physical and chemical stability, as well as mechanical strengthen is not as good as demand. Fluorophosphate glass has the merits of both fluoride glass and phosphate glass. Its fluorescence spectrum is broad and even, and the fluorescence lifetime is long. It is easier than phosphate glass to remove OH groups during melting. At the same time its glass-forming ability and mechanical strength are better than fluoride glass. By far there have been some reports about fluorophosphate glass as the host matrix of optic amplifier at home and abroad. However, the researches are far from systematic and complete. In this dissertation the spectroscopic properties of erbium and thulium doped fluorophosphate glass were investigated. The features and feasibilities of fluorophosphate glass used as the host matrix of rare earth doped fiber amplifier were discussed. With the rapid development of technology involving information processing, data memory, underwater communication and video display, cheap and efficient lasers with high performance within the visible band are needed more and more. Upconversion fiber, which can be pumped by laser diode, is featured with multi-wavelength output and simple structure. It attracts more and more attentions. Researches on the materials for upconversion laser within visible band were quite active in recent years. Presently most of the upconversion fiber lasers depend on fluoride glass, which has comparatively high loss and low mechanical strength. At the same time the manufacture of this glass is complex and expensive. It is significant to research and develop new glass for upconversion fiber laser. In this dissertation the upconversion spectroscopic properties of fluorophosphate glass with low phosphate content were investigated. The fluorophosphate glass which was suitable for upconversion fiber laser was explored. In chapter one, the research progresses on fiber amplifier and its host matrices, upconversion luminescence materials and fluorophosphate glasses were reviewed. The purpose and project of the dissertation were proposed. In chapter two, the experiments, testing and measuring methods and theories for data analyses were presented. The chapter three, four and five are the main part of the dissertation. In the third chapter the relationship among the composition, structure and stability against crystallization of fluorophosphate glass was discussed. For the glasses with components including alkali fluorides, alkaline earth fluorides, the density and stability against crystallization can be tailored by adjusting the content or the variety of fluoride components. When the mol percentages of alkali and alkaline earth fluorides are equal, the stability against crystallization is better. In the alkali fluorides, the introduction of LiF increases density and decreases the stability against crystallization. In bivalent alkaline earth fluorides, MgF2 has comparatively strong ability to form glass. The increase of CaF2 content in the composition decreases the characteristic temperatures and glass-forming ability simultaneously. The increment of the component number of alkali and alkaline earth fluorides contributes to the formation of bridged oxygen and enforces the network in glass. As a result the thermal stability is improved and the inhibition to nucleation and crystallization during melting process increases. In chapter four the spectroscopic properties of thulium doped fluorophosphate glass in band S and erbium doped fluorophosphate glass in band C were researched. For the (60-x)Mg0.17Ca0.49Sr0.17Ba0.17F2-40AlF3-xAl(PO3)3-0.05Tm2O3 glass system, the increment of Al(PO3)3 content does not affect maximum phonon energy but result in the augment of density of high phonon energy states. The introduction of Al(PO3)3 benefits for the stability against crystallization and does very little harm to spectroscopic properties in S band, as long as its content is not more than 7mol%. For the (60-x)Mg0.17Ca0.49Sr0.17Ba0.17F2-40AlF3-xAl(PO3)3-0.8ErF3-2.4YbF3 glass system, it is found that the introduction of NaF or PbF2 does good to the stability against crystallization. With the increase of NaF content, the maximum phonon energy keeps constant and the density of high phonon energy states increases, and the stimulated-emission cross section and fluorescence width decrease. With the increase of PbF2 content, the maximum phonon energy decreases a little. At the same time the stimulated-emission cross section and gain properties increase. As far as the stimulated-emission cross section and broadband properties are concerned, these glasses are close to tellurite glass, and are much better than germanate glass. Judd-Ofelt theory was used to analyze the influence of YbF3 as not a sensitizer but as a component of glass on the spectroscopic properties of erbium around 1530nm emission. It was found that YbF3 as a component prolongs the fluorescence lifetime of Er3+. With the increase of Yb3+ concentration, there is a maximum for the fluorescence lifetime of Er3+ because of the sensitization of Yb3+. The radiation trapping around 1530nm of Er3+ in fluorophosphate glass was investigated. Due to the influence of radiation trapping, glasses with different thickness exhibit different dependences of fluorescence lifetime on the Er3+ concentration. An empirical way to quantitatively evaluate the influence of radiation trapping on fluorescence lifetime and width is proposed. Fluorophosphate glass with the composition of 19NaF-7MgF2-21CaF2 -5SrF2-5BaF2-30AlF3-5YF3-4Al(PO3)3-4ErF3 was prepared. The concentration of Er3+ amounts to 7.45×1020ions/cm3. The measured fluorescence lifetime is about 8.20ms. The comparatively long fluorescence lifetime is due to the low water content and high phonon energy of matrix glass. In chapter five, the upconversion properties of Yb3+/Tm3+, and Er3+/Yb3+/Tm3+ codoped fluorophosphate glasses under 970nm LD excitation were investigated respectively. The sensitization of ytterbium to thulium is a three-photon process through successive energy transfer when the concentration of ytterbium is low; when the concentration of ytterbium is high it is a two-photon process through cooperative upconversion. Series of Yb3+/Tm3+ codoped fluorophosphate glasses with various metaphosphate contents were prepared. With the increase of metaphosphate content, the density of high phonon energy states increases. Consequently the multiphonon relaxation rate rises and efficiency of upconversion decreases. On the whole, these glasses still show intense blue upconversion luminescence because the metaphosphate content is comparatively low. In Er3+/Yb3+/Tm3+ codoped fluorophosphate glasses, the dependences of red, green and blue upconversion luminescence on the concentrations of rare earth ions were studied. The intensities of upconversion fluorescent lights, as well as their ratios to each other can be tailored by changing the concentration of Yb3+. Tm3+ behaves as the sensitizer to Er3+ for the red and green upconversion luminescence. The effect of the sensitization depends heavily on the concentration of Yb3+. Er3+ acts as quenching center for the blue upconversion luminescence of Tm3+. The blue luminescence quenching occurs at a lower concentration of Tm3+ in Er3+/Yb3+/Tm3+ codoped glasses than in Yb3+/Tm3+ codoped glasses. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15394]  |
| 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 | 廖梅松. 稀土掺杂氟磷玻璃的光谱性质[D]. 中国科学院上海光学精密机械研究所. 2007. |
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