稀土掺杂氟化物玻璃光纤制备及中红外激光特性的研究

Fluoride glass fiber lasers in mid-Infrared range of 3-5μm hold important scientific and practical value in remote sensing, ranging, guidance, communication, gas detection, spectral analysis and laser medical field. In this paper, the key scientific problems such as thermal properties, interfacial loss and thermo-optic effect of fluoride glass fiber are studied. The thermal behavior of fluoride glass is controlled by systematically studying the structural kinetics of glass transition in the relaxation process. Fluoride glass components with large size and high optical quality are obtained in this process and it reveals the influence relationship of the mid-infrared emission characteristics and ion concentration, glass structure, absorption characteristics and pump wavelength of rare earth ions doped fluoride glass . In addition, regulate the microstructure between the fiber cladding and core interface to eliminate the defects and reduce the loss, gaining a low loss rare earth doped fluoride double clad glass fiber. This paper presents a heterogeneous fiber splicing technique which can adjust the steady-state temperature gradient field, obtaining the all-fiber structure, and in combination with the special design of the U-shaped water with the loading heat sink, and ultimately achieves the mid-infraredlaser output with high power (> 1W) and high slope efficiency (> 20%)in rare earth doped fluoride double-clad glass fiber. The successful launch of this project lies the theoretical and technical foundation for the infrared laser glass fiber materials.

3-5μm波段中红外氟化物玻璃光纤激光在遥感、测距、制导、通讯、气体探测、光谱分析及激光医疗等领域具有重要的科学和应用价值。本项目主要针对氟化物玻璃光纤热学性能、界面损耗和热光效应等关键科学问题进行研究，通过系统研究弛豫过程的结构异质行为玻璃转变动力学，调控氟化物玻璃的热学性能，获得大尺寸高光学质量的氟化物玻璃组分；揭示掺稀土氟化物玻璃中的中红外发光特性与离子浓度、玻璃结构、吸收特性及泵浦波长之间的影响规律。调控光纤包层/芯层界面微结构，消除缺陷和降低损耗，获得低损耗稀土掺杂氟化物双包层玻璃光纤。提出稳态温度梯度场可调控的异质光纤熔接技术，实现全光纤结构，结合对装载热沉采取U形通水的特殊设计，最终在稀土掺杂氟化物双包层玻璃光纤中实现中红外波段高功率（>1W）和高斜率效率（>20%）的激光输出。项目顺利开展为中红外激光玻璃光纤材料奠定理论和技术基础。

3-5μm波段中红外氟化物玻璃光纤激光在遥感、测距、制导、通讯、气体探测、光谱分析及激光医疗等领域具有重要的科学和应用价值。本项目针对氟化物玻璃光纤热学性能、界面损耗和热光效应等关键科学问题进行研究，系统研究弛豫过程的结构异质行为玻璃转变动力学，并对样品的微观结构及性能进行测试，调控氟化物玻璃的热学性能，获得大尺寸高光学质量的氟化物玻璃组分；通过优化熔制温度制度、温场控制、气氛控制、干燥度控制、浇注控制、坩埚形体及均匀化搅拌等工艺环节和制备技术，成功制备出大尺寸高光学均匀性低羟基含量（<1ppm）氟化物玻璃；进而采用管棒法制备光纤预制棒，结合氟化物光纤内外包层的合理设计，成功拉制出高质量低损耗氟化物光纤；搭建掺稀土氟化物双包层光纤性能测试和检测平台，选择最佳匹配的芯径和数值孔径的光纤，实现了中红外波段高效（>20%）的W级激光输出。项目顺利开展为中红外激光玻璃光纤材料以及固体激光器奠定技术基础和科学指导。