哑铃形全保偏耗散孤子超快锁模光纤激光器关键问题研究

In the traditional mode-locked fiber lasers, NOLM-based figure-8 mode-locked fiber lasers have advantages of low cost and all-fiber all-polarization construction, but They also owns several disadvantages, such as inflexible parameter adjustment, dependence on the optical isolators, which limit their output pulse performance. In view of these shortcomings, we propose a new dumbbell-shaped mode-locked laser strcture, which has the advantages of compact structure, isolator-free, high power capacity, flexible control of parameters and so on, thus has great research potential. The project is aimed at generating high-performance dissipative soliton ultrafast pulses from all-polarization-maintaining dumbbell-shaped mode-locked fiber laser. The therotical pulse dynamics model of dumbbell-shaped modelocked fiber laser will be studied. The conditions and physical mechanism of genrating ultrafast dissipation solitons in the dumbbell-shaped mode-locked laser are analyzed. The limitation of the output pulse performance and the corresponding solution are studied. The factors affecting the self-starting performance of the dumbbell-shaped dissipative soliton mode-locked lasers are studied. Breakthrough of output pulse performance of dumbbell-shaped ultrafast mode-locked fiber laser will be achieved. The project will provides theoretical support and practical guidance for constructing a new generation of dumbbell shaped ultrafast pulse laser with compact structure, superior performance and high reliability.

在传统的锁模光纤激光器方案中，基于非线性环形镜的8字形锁模光纤激光器有成本低、可实现全光纤全保偏等突出优势，但同时也有参数调节不灵活、依赖光隔离器等缺点限制其输出脉冲性能提升。针对这些缺点我们提出了一种全新的哑铃形锁模激光器方案，该方案具有结构紧凑、无隔离器、功率承受能力高、参数灵活可控等优点，具有很大研究潜力。该项目以基于哑铃形全保偏锁模方案的高性能耗散孤子超快脉冲产生为主要目标，开展基于哑铃形结构的锁模光纤激光器脉冲动力学理论模型研究，分析从哑铃形全保偏锁模激光器中产生超快耗散孤子脉冲的条件和物理机制；研究输出脉冲性能提升的限制和相应的解决方案，最终实现全保偏耗散孤子超快锁模光纤激光器输出脉冲性能上的突破；同时研究哑铃形耗散孤子锁模激光器自启动性能影响因素。为构建结构紧凑、性能优越、可靠性高的新一代哑铃形超快脉冲光源提供理论支撑和实践指导。

在传统的锁模光纤激光器方案中，基于非线性环形镜的8字形锁模光纤激光器有成本低、可实现全光纤全保偏等突出优势，但同时也有参数调节不灵活、依赖光隔离器等缺点限制其输出脉冲性能提升。针对这些缺点我们提出了一种新的哑铃形锁模激光器方案，该方案具有结构紧凑、无隔离器、功率承受能力高、参数灵活可控等优点。该项目以基于哑铃形全保偏锁模方案的高性能耗散孤子超快脉冲产生为主要目标，开展了哑铃形锁模激光器脉冲动力学研究，基于非线性薛定谔方程和速率方程建立了哑铃形锁模光纤激光器分立元件仿真模型，基于MATLAB编写了专用数值模拟工具；基于大规模数值模拟计算结果，利用激光器状态参数空间分析方法，分析了哑铃形掺镱锁模激光器结构参数和输出脉冲特性的关系，揭示了产生超快耗散孤子脉冲的条件和机制；在理论研究的基础上，通过优化激光器结构，实验上实现了哑铃形全保偏掺镱锁模光纤激光器大能量超快耗散孤子输出，获得了脉冲能量21 nJ，压缩后脉冲宽度187 fs的大能量耗散孤子脉冲输出，是目前百飞秒级全光纤全保偏掺镱锁模光纤激光器最大脉冲能量；以及脉冲能量最高0.6 μJ、平均功率最高5.5 W的高功率大能量耗散孤子共振脉冲输出，是目前全光纤全保偏掺镱锁模光纤激光器的最高输出功率。此外还对哑铃形全保偏掺镱锁模光纤激光器自启动性能的影响因素及其原理进行了实验研究，得出了提高哑铃形锁模激光器自启动性能的建议。该项目的研究对发展低成本、轻量级、高可靠性、实用性高超快光纤激光器具有重要意义。