近日，北京大学刘开辉团队实现了二维异质结构纳米腔在全光纤超快激光器中的鲁棒锁模。相关论文于2025年9月3日发表在《光：科学与应用》杂志上。

基于光纤的可饱和吸收器（SA）可以在环形腔内实现锁模，是超快全光纤激光器的核心部件。然而，在高致密度的光纤上集成SA存在饱和吸收性能不平衡和锁模性能不稳定的问题。

研究组通过在光纤端面集成由二维石墨烯异质结构组成的纳米腔，提出了一种自动锁模SA。通过对异质结构内光场的精确调制，他们证明了饱和强度的显著降低（~65%）和孤子动态过程的改善。所设计的异质结构有利于形成稳定的单孤子态，从而实现机器人锁模。在异质结构-SA中实现了对腔内极化变化的高容忍度（~85%，而裸石墨烯为20%）。他们设计的异质结构-SA代表了超紧凑锁模全光纤激光器发展的重要进步，提供了增强的可集成性和稳定性。

附：英文原文

Title: Robust mode-locking in all-fiber ultrafast laser by nanocavity of two-dimensional heterostructure

Author: Shao, Jiahui, Yao, Guangjie, Wu, Xuecheng, Lin, Kaifeng, Zhang, Shaoyi, Cheng, Xu, Zhong, Ding, Liu, Chang, Liu, Can, Wang, Fengqiu, Liu, Kaihui, Hong, Hao

Issue&Volume: 2025-09-03

Abstract: The fiber-based saturable absorber (SA) that enables mode-locking within a ring cavity serves as the core component of the ultrafast all-fiber lasers. However, the integration of SAs onto fibers with high compactness suffers from imbalanced saturable absorption properties and unstable mode-locking performance. Here, we present a robust mode-locking SA by integrating a nanocavity composed of a two-dimensional graphene heterostructure on the fiber end facet. We demonstrate a significant reduction in the saturation intensity (~65%) and improved soliton dynamic processes through precise modulation of the optical field within the heterostructure. The designed heterostructure facilitates the formation of a stable single-soliton state for robust mode-locking. A high tolerance to intracavity polarization variations is achieved in the heterostructure-SA (~85% compared to 20% for bare graphene). Our designed heterostructure-SA represents an important advancement in the development of ultracompact mode-locked all-fiber lasers, offering enhanced integrability and stability.

DOI: 10.1038/s41377-025-02018-2

Source: https://www.nature.com/articles/s41377-025-02018-2