多模光纤中的时空孤子动力学特性研究

Soliton laser pulses in single mode fibers have become an indispensable tool in modern telecommunications, industry and related areas. However, the current faced difficulties are that the small core of used single mode fiber makes it easy to stimulate many detrimental nonlinear effects and thus limit the improvement of the pulse energy and the communication capacity; while the large-mode-area photonic crystal fiber can provide a large mode area, but its damage threshold is low and it is also not compatible with commonly used fiber components. In this program, we propose and study the generation and nonlinear dynamics of multimode optical solitons in step-index multimode fibers. The combination of excellent optical, thermal and mechanical features of silica fibers with the advantages of large mode area of multimode fibers will provide a platform to achieve multimode-locking, thus improve the soliton pulse energy/peak power, resolving the limit of energy advancement in fiber lasers. In addition, research on spatiotemporal interaction of multimode optical solitons will help to uncover many novel physical phenomena, and also trigger many new applications. Therefore, implementation of this program will develop a new technology on pulse energy improvement in multimode fiber lasers, and novel optical effects based on spatiotemporal interaction of solitons. This will not only help to advance the laser dynamics in multimode fibers but will also improve the core competence of our country in the fiber laser regime.

单模光纤中的孤子激光脉冲是现代通信、工业生产等领域中不可或缺的工具。但是因为单模光纤纤芯小，激光传输时容易激发各种非线性效应，限制了脉冲能量和通信容量的进一步提升，而光子晶体光纤虽然能实现较大的模场面积，但损伤阈值低且难以与常规光纤器件兼容。本项目提出阶跃折射率多模光纤中的孤子脉冲产生和动力学特性研究，结合硅基光纤优异的光、热、机械特性来实现多模光孤子锁模，解决限制光纤中孤子脉冲能量和峰值功率的关键科学问题；研究多模光纤孤子基于时空耦合的新颖非线性光学现象，探寻多维光孤子的新特性和新应用，发展基于多模光纤的激光脉冲能量提升新技术和基于时空耦合的新光学效应，这将有助于推动多模光纤激光动力学的发展、提升我国在光纤激光技术领域的核心竞争力。

单模光纤中的孤子激光脉冲是现代通信、工业生产等领域中不可或缺的工具。但是因为单模光纤纤芯小，激光传输时容易激发各种非线性效应，限制了脉冲能量和通信容量的进一步提升。我们提出了采用阶跃折射率多模光纤来形成激光孤子脉冲，研究了多模孤子的形成、稳定及传输的动力学过程，并探索了如何进行横模控制，实现了多个横模的锁定，得到了稳定的多模孤子，脉冲能量大于500纳焦，平均功率大于10瓦。另外，利用模式选择技术实现了脉冲能量大于20纳焦、光束质量M2因子接近1的单横模锁模脉冲。所取得的研究成果，加深了对多模光纤中光孤子时空耦合非线性特性的理解，初步解决了限制光纤中孤子脉冲能量和峰值功率的关键科学问题，有助于为新一代激光通信及能量传输提供核心光源和脉冲控制技术。