折射率沟槽结构光纤激光侧面泵浦耦合特性研究

项目名称： 折射率沟槽结构光纤激光侧面泵浦耦合特性研究

项目编号： No.61307057

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 无线电电子学、电信技术

项目作者： 肖起榕

作者单位： 清华大学

项目金额： 28万元

中文摘要： 光纤激光器具有转换效率高、光束质量好等优点，成为激光研究的一个热点。而如何将泵浦光通过光纤耦合器可靠、高效地耦合到增益光纤成为研制高功率光纤激光器的关键问题。现有光纤耦合器存在纤芯损耗大、反向隔离度低及无法应用于大模场光纤等问题；且国外对其实行严格技术封锁，国内外技术差距较大，急需自主研究创新以达到国际先进水平。 本项目提出的折射率沟槽结构光纤激光侧面泵浦耦合器，泵浦光经过三段耦合区高效地耦合到主光纤。此耦合器具有独特的折射率沟槽结构，在制作过程中不破坏主光纤纤芯，具备信号和泵浦光插入损耗小、反向隔离度高和可应用于大模场光纤等优势。本项目建立有限差分三维空间下完美匹配边界条件大广角光束传播方法，对耦合器模式耦合损耗机理进行深入研究，为耦合器设计及实验制作提供指导。其次，开展耦合器制作工艺探索，掌握全套制作方法，拟首次实现耐受功率为：泵浦光3kW，连续信号光1kW，脉冲信号光1MW的光纤耦合。

中文关键词： 光纤激光；泵浦耦合器；侧面泵浦；连续激光；脉冲激光

英文摘要： Fiber lasers became one of the most interesting research fields due to its high electro-optic conversion efficiency and high beam quality. Pump light reliably and efficiently coupled into a gain fiber is critical technology in the high power fiber laser with fiber pump coupler. There are several disadvantages in existing fiber pump coupler, for instance, large signal insertion loss, low backward isolation and mismatch with large-mode-area (LMA) fiber and so on. Moreover, the advanced technology is blockaded by foreign countries. There is a wide gap between the domestic technology and foreign technology, it is imperative to research and innovate independently in order to reach international advanced level. This project develops a new fiber laser side-pumped coupler with index valley configuration, and it is consisted of multi-pump fibers and a main fiber. Pump light transfers to main fiber through three coupling sections with high coupling efficiency. There is a refractive index valley in this coupler and the core of main fiber wasn't destroyed through fabrication process, which make this coupler have the advantages of low insertion loss of signal light, high coupling efficiency of pump light, high backward isolation and satisfaction with LMA fiber,etc. This project studies deeply coupling loss mechanism of the c

英文关键词： fiber laser；pump coupler；side pumping；coninuous-wave laser；pulse laser