时空锁模光纤激光器是当前高功率、高能量激光技术新的研究方向。本项目基于Kerr自清洁技术实现输出高质量准基模光束的时空锁模光纤激光器，解决目前该类型激光器输出光束截面呈现“散斑”的问题。主要研究工作有：（1）构建时空锁模光纤激光器的理论模型，研究脉冲建立的动力学过程及腔内参数对脉冲时空特性的影响；（2）设计和制备新型多模光子晶体光纤，用于有效调控激光腔内Kerr自清洁的实现；（3）搭建时空锁模光纤激光器，研究腔内关键参数对Kerr自清洁效果的影响，直接产生高光束质量的脉冲激光。通过本项目的研究，获得脉宽小于600fs、光束质量因子小于1.8的飞秒脉冲准基模光束。本项目的开展，不仅能加深对时空锁模脉冲产生的动力学过程的理解，而且可以突破时空锁模光纤激光器在光束质量方面的限制，为该类型激光器在工业生产、科学研究、军事等领域的应用奠定基础，具有重要的科学意义和应用价值。

Spatiotemporal mode-locked fiber laser (SMLFL) is a new research topic in the fields of high power, high energy lasers. In this project, we employ Kerr self-cleaning technique to solve the speckle beam problem of the SMLFL, and obtain high quality, quasi-fundamental-mode beam. The main work includes: (1) The theoretical model of the SMLFL will be established to investigate the buildup dynamics of the mode-locked pulse and the influence of the cavity parameters on the pulse characteristics. (2) We will design and fabricate the novel multimode photonic crystal fiber for realizing the Kerr beam self-cleaning in the laser. (3) Finally, the SMLFL will be constructed and the influence of the cavity parameters on the degree of the Kerr beam self-cleaning will be also investigated in order to achieve high quality pulse beam. Through these investigations, the SMLFL will output the quasi-fundamental-mode beam with pulse width less than 600 fs and beam quality parameter less than 1.8. This project’s development will not only deepen the understanding of the dynamics of the spatiotemporal mode-locked pulse, but also overcome the bad beam quality of the SMLFL to generate high quality quasi-fundamental-mode beam. It will facilitate the applications of the SMLFL in the fields such as industry, scientific research and military. These investigations on SMLFL have important scientific significance and practical application value.