超快光纤激光器中耗散孤子碰撞瞬态动力学特性研究

Dual-comb generation in ultrafast soliton fiber lasers has attracted much attention recently because of their versatile applications in fields such as dual-comb spectroscopy, laser gyroscope and laser ranging. In fact, the soliton collisions are the intrinsic features in dual-comb ultrafast fiber lasers. The outcome of the soliton collisions not only influences the performance of dual-comb laser sources, but also their further applications in the related fields. However, the transient dynamics of the dissipative soliton collisions in ultrafast fiber lasers were rarely investigated experimentally. In this project, relying on the real-time spectral diagnostic method based on the dispersive Fourier transform (DFT), we will investigate the transient dynamics of the dissipative soliton collisions in ultrafast fiber lasers. This project will aim to solve the understanding of dissipative soliton collisions towards the fundamental physics and practical applications of dual-comb laser sources. The following issues will be addressed: firstly, the dissipative soliton collisions in bidirectional mode locking fiber laser will be analyzed; then we will study the soliton collisions as well as their physical mechanisms in a dual-wavelength mode-locked comb laser. In addition, the special case for the soliton collision between the dissipative and conventional solitons will be studied and analyzed. Finally, searching for transient dynamics of multiple dissipative soliton collisions will be also detected and carefully investigated, as well as the influence of the multiple dissipative soliton collisions on the formation of rogue waves. Carrying out this project would not only deepen the physical understanding of dissipative soliton collisions, but also would be important to develop the high-performance dual-comb laser sources and the development of ultrafast fiber laser technologies.

双光频梳超快孤子光纤激光器在双光梳光谱学、激光陀螺、激光测距等领域有重要的应用价值。孤子碰撞是双光频梳超快光纤激光器中难于避免的一种内在属性。碰撞结果不仅决定了光频梳光源性能的好坏，而且还影响其在相关领域的应用。然而，对超快光纤激光器中的耗散孤子碰撞瞬态动力学特性的研究却鲜有报道。本项目拟结合实时光谱探测技术（色散傅里叶变换），在光纤激光器中开展耗散孤子碰撞瞬态演化机理和特性的研究。项目将从双光频梳光源实际应用和基础物理特性研究出发，主要内容包括：①分析双向锁模超快光纤激光器中耗散孤子碰撞特性；②弄清楚双波长光频梳中孤子碰撞机理；③探索研究耗散孤子与守恒孤子的碰撞演化情况；④观察耗散多孤子碰撞瞬态特性，探索多孤子碰撞特性对光怪波形成的影响。本项目的开展，不仅能够加深对耗散孤子碰撞物理特性的理解，为研制高性能的双光频梳光源提供理论依据，而且对于进一步推动超快光纤激光技术的发展具有重要的意义。

本项目主要研究双光频梳超快光纤激光器中耗散孤子碰撞瞬态动力学特性，并揭示其内在物理机制。在本项目的资助下，我们围绕超快光纤激光器中的耗散孤子碰撞特性、新型孤子瞬态动力学、高性能超快光纤激光技术三方面开展了研究工作，取得的主要研究成果可以概括为以下几方面：1. 在超快光纤激光器耗散孤子碰撞瞬态动力学研究方面，我们揭示了双向锁模光纤激光器（双光频梳）中孤子碰撞诱导非线性行为相似性以及碰撞诱导偏振不稳定性，首次观察到了双波长锁模超快光纤激光器中孤子碰撞诱导周期爆炸现象；此外，我们还研究了多孤子爆炸状态下由随机孤子碰撞相互作用产生瞬态光怪波现象。2. 在超快光纤激光器中新型孤子瞬态动力学特性研究方面，我们首次揭示了具有能量不变、波形周期变化的“隐形孤子脉动”现象；观察到了反常色散光纤激光器的孤子爆炸现象，将孤子爆炸概念拓展到反常色散机制；此外，我们还研究了Mamyshev光纤振荡器中多脉冲瞬态动力学特性。3. 在高性能锁模脉冲光纤激光技术研究方面，我们提出1.7微米波段超快光纤激光器研制，基于啁啾脉冲放大技术，最终在1.7微米波段获得了高达1.95W平均功率（压缩后1.3W）、脉冲宽度为348fs的高性能光纤激光脉冲输出。同时，我们采用金兹堡-朗道方程对正常四阶色散光纤激光器进行数值模拟，提出了耗散四次孤子概念，为高能量脉冲光纤激光器研究提供一种新的设计思路。