光纤中的光致连续损伤及其监测和阻断技术的基础研究

Light-induced continuous damage of optical fiber, also known as fiber fuse, is a phenomenon when the power density in a fiber exceed a particular threshold power, a confined plasma is generated in the fiber core, which will leave continuous air hole and bring irreversible damage to the fiber. This phenomenon is extremely threatening to both the high capacity optical communication systems and high power fiber laser applications and has been acknowledged as one of the key factors which limits the further increase of both the capacity of fiber communication and the output power of optical fiber laser. Due to these reason, it is of great significance to study light-induced continuous damage of optical fiber in order to support the rapid development of optical communication and optical fiber laser application of China..In this project, we plan to theoretically and experimentally study the generation mechanism and detection/termination technology of light-induced continuous damage of optical fiber. We will develop a 3D multi-physical field coupling analysis model with consideration of fiber mode power distribution to study its generation mechanism; we will use a heterodyne frequency measurement method synchronized with high speed camera to systematically study its generation, propagation and termination process. By employing these two originally proposed methods, we will study the dependence of it on the waveguide structure, materials composition, and fabrication process of optical fibers; we will also explore its detection/termination method and develop optical fibers with high damage threshold power and optical devices to stop it.

光纤中的光致连续损伤是当光纤中的光功率密度超过某一阈值时，纤芯发生等离子化并形成连续气孔，给光纤带来不可逆转损伤的连续破坏现象。这一现象破坏范围大，对大容量光纤通信系统及大功率光纤激光器构成严重威胁，被认为是限制光纤传输容量及光纤激光输出功率进一步提高的重要制约因素，近年来逐渐受到学术界和工业界的关注，具有重要的研究价值。.本课题拟对光致连续损伤的发生机制及其有效监测与阻断技术开展理论与实验研究。通过引入光纤径向模场分布，建立三维多物理场耦合仿真平台，探索光致连续损伤的发生机制；建立以高精度外差频率测量与超高速摄影同步测量为核心的测试平台，对光纤损伤的全过程进行实验研究；采用上述创新性技术路线，系统研究光纤结构、材料组分、制备工艺与光致连续损伤的关系；探索其实时监测与阻断方法，研制具有高损伤阈值的光纤及阻断器件。为该领域的研究提供技术储备，为我国光纤通信及光纤激光领域的发展做出贡献。

光纤中的光致连续损伤对大容量光纤通信系统构成严重威胁，研究其发生机理、监测及防御手段对于保障大容量光纤通信系统安全具有重要意义。本项目对光致连续损伤的发生机制及其有效监测与阻断技术开展了理论与实验研究。研究了光致连续损伤的发生机制；建立了基于高精度外差频率测量技术的测试平台，对光纤损伤的全过程进行实验研究；研究了光纤结构、材料组分与光致连续损伤的关系，研究结果表明，纯二氧化硅纤芯、大有效面积少模光纤具有高的光致连续损伤耐受特性；研究过程中，观察到单模光纤与少模光纤中由于不同原因导致的周期性速度振荡行为及其对触发、功率变化、停止等过程的瞬态速度响应特性；提出了基于光频域反射仪的光致连续损伤实时监测与定位系统；研制了具有良好光致连续损伤耐受特性与综合性能的3种新型大有效面积少模和多芯光纤。提出的环辅助结构弱耦合少模光纤，与传统阶跃结构光纤相比，将最小模式有效折射率差提高了2.2倍，并实验验证了其具有高的鲁棒性，研制的与其配套的超低损耗宽带模式复用及解复用器的LP11模式插入损耗低至0.3dB；提出的面向大规模高速光互连应用的全波段少模多芯光纤与标准单模及多模光纤兼容，适用于不同波长、速率、及链路长度；提出的包层氟掺杂芯径优化超宽波段多模光纤，其有效模式带宽高于OM5光纤带宽指标，充分满足下一代高速CWDM和SWDM传输需求。