新型硫系玻璃光纤制备及其非线性应用

Chalcogenide Glass (ChG) materials have many desirable properties in the mid-Infrared (mid-IR) spectrum, such as excellent transmissivity and ultra-high optical nonlinearity. Therefore, optical fibers manufactured with ChGs show great scientific importance as well as market value in the fields of mid-IR nonlinear optical devices (such as Super Continuum Generation (SCG) sources and raman fiber lasers), biological sensing, and all-optical network. However, current research work on ChG fibers is fundamentally focused on enhancing the nonlinearity of ChGs via material optimization. Other important aspects of ChG fibers, such as optimization of fiber structures, enhancement of the light-coupling efficiency, and packaging of prototype ChG fiber devices, are mostly neglected. To cope with the current research limitation, we propose a comprehensive study of ChG optical fibers, targeting at obtaining a series of advanced ChG materials of ultra-high third-order optical nonlinearity, designing new fiber structures for low-loss optical transmissions, building prototype ChG fiber devices (with proper coupling mechanisms) that can result in SCGs over a spectral range of 2~8 um. To accomplish those targets, we will study the regulating mechanism of material compositions of ChGs on their nonlinear optical properties, the regulating mechanism of ChG fiber structures on their dispersion performance, and the physical foundations of achieving 2~8 um SCGs in ChG fibers. This research work completes the technology-chain of ChG fibers from the fundamental research on ChG base materials to the completion of functional ChG fiber devices, building solid foundations for the development of next-generation mid-IR super continuum sources with proprietary intellectual property, infrared photonic devices, optical components for high speed all-optical network, and sensor-chips for biological sensing. .

由于硫系玻璃具有优良的透红外和极高的光学非线性特性，硫系玻璃光纤在中红外超连续谱（SC）谱和拉曼光纤激光器等非线性光学、生物传感、全光网络器件等领域呈现出重要的科学研究价值和巨大的市场应用前景，但目前，硫系光纤的中红外SC谱光源主流研究在高非线性光纤基质材料组成、光纤结构设计、泵浦技术、原型器件封装等方面存在严重不足。本项目拟通过对新型高光学非线性硫系玻璃组成的调控机理、硫系微结构光纤色散调控方法、硫系光纤2-8微米SC谱产生条件等基础科学问题进行深入研究，获得系列新型高三阶非线性硫系玻璃材料，设计出新结构的硫系微结构光纤，解决硫系光纤低损耗制备关键技术，研制出2-8微米中红外SC谱输出的新型硫系光纤及光纤耦合模块原型器件，从而完整实现从底层材料设计到器件研制的技术链，为今后大力推动自主知识产权的新型中红外SC谱光源、红外光子器件、全光网络光器件及生物传感芯片等产业的发展奠定坚实的基础。

中远红外波段SC谱光源在生物医学、气体检测、食品质量检测及红外激光对抗等领域具有重要的应用前景。硫系玻璃光纤是目前唯一能实现中远红外波段（>10um）SC谱输出的高非线性光纤。国际上许多知名光电子研究机构从2009年起相继开展了硫系光纤中红外SC谱理论和实验研究，并取得了系列研究成果。本项目启动时国内在此领域基本处于空白状态。. 本项目系统深入地开展了新型高非线性硫系玻璃组成的调控机理、硫系光纤结构设计和非线性特性数值模拟、硫系光纤SC谱输出特性的基础研究，以及硫系光纤拉制及光纤耦合模块封装关键技术研发。通过对Ge-Sb-Se、Ge-Sn-Se、Ge-Sn-S等新型硫系玻璃组分与非线性折射率n2和非线性系数值β之间的变化规律、以及玻璃结构与带隙宽带对其三阶光学非线性的影响，发现三光子谐振效应、平均配位数、玻璃中同极性键对其光学非线性影响最大，在此基础上拉制出多种新型高非线性硫系光纤，获得了超宽（>10um）中红外SC谱输出。在制备的Ge-Te-AgI双包层单模硫系光纤中，采用工作波长为7um 、脉宽150fs，频率1kHz的 OPA激光泵浦获得了强度动态范围±40dB、覆盖2-16um中远红外SC谱输出，该SC谱宽范围是目前国际上报道的最宽SC谱。在拉制的7cm长Ge-As-Se-Te拉锥硫系光纤中获得了1.7-12.7 μm 中远红外SC谱输出，该结果是国际上在阶跃型拉锥硫系光纤中获得最宽的SC谱输出报道。此外掌握了具有自主知识产权的从硫系玻璃提纯-阶跃型及微结构硫系光纤预制棒挤压制备-PES塑料包覆预制棒光纤拉制-硫系光纤端面抛光及跳线加工的一整套完整流程的硫系光纤制备技术，制备的As-Se、Ge-As-Se-Te等光纤最低损耗小于1dB/m。. 项目在Laser Photon. Rev.、Prog. Mater. Sci.、Opt. Lett.、Opt. Express等期刊共发表72篇学术论文，其中SCI论文60篇，2篇ESI高引论文；申请国家标准5项（已批准2项），申请发明专利23项（已授权14项），出版学术专著1部；培养国家级人才1名，研究生12名。承办2次学术研讨会，30余人次参加国内外学术会议并作报告。本项目相关成果引起国际同行关注，为今后推动自主知识产权的全光纤化中远红外SC谱光源、红外光子器件及生物传感芯片等产业的发展奠定了基础。