百兆赫兹重频的轨道角动量模式飞秒光纤激光器  

Orbital angular momentum mode femtosecond fiber laser with over 100 MHz repetition rate

作　　者：吴航 陈燎 李帅 杜禺璠 张驰 张新亮[1] Wu Hang;Chen Liao;Li Shuai;Du Yu-Fan;Zhang Chi;Zhang Xin-Liang(Wuhan National Laboratory for Optoelectronics,School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学光学与电子信息学院,武汉光电国家研究中心,武汉430074

出　　处：《物理学报》2024年第1期181-192,共12页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61505060,61631166003,61675081,61735006,61927817)资助的课题。

摘　　要：轨道角动量(orbital angular momentum,OAM)模式激光器在大容量通信系统、激光加工、微粒子操作、量子光学领域研究有潜在应用价值.OAM模式飞秒光纤激光器具有结构简单、成本低、峰值功率高等优势而被重点研究.当前OAM模式飞秒光纤激光器在重复频率、脉冲宽度、光谱宽度等关键参数上分别都有突破,但性能难以兼得,且重复频率目前在数十MHz.本文基于模式相位匹配原理,制作了大带宽的模式耦合器,结合非线性偏振旋转锁模机理,通过优化腔内的色散,搭建了百兆赫兹重复频率的OAM模式飞秒光纤激光器.实验结果表明,一阶OAM模式光纤激光器的重复频率可达113.6 MHz,脉冲半高全宽98 fs,10 d B带宽可达101 nm;二阶OAM模式光纤激光器的重复频率可达114.9 MHz,脉冲半高全宽60 fs,10 d B带宽可达100 nm.相对于已报道的方案,本文报道的方案在重复频率、脉宽和光谱宽度等关键参数上综合性能较好,有望更广泛地应用于OAM通信、粒子操控等研究领域.Orbital angular momentum(OAM) lasers have potential applications in large capacity communication systems,laser processing,particle manipulation and quantum optics.OAM mode femtosecond fiber laser has become the research focus due to the advantages of simple structure,low cost and high peak power.At present,OAM mode femtosecond fiber lasers have made some breakthroughs in key parameters such as repetition frequency,pulse width,spectrum width,but it is difficult to achieve good overall performance.Besides,the repetition rate is tens of MHz at present.In this paper,a large-bandwidth mode coupler is made based on the mode phase matching principle.In coupler,the first order mode coupler with 3 dB polarization dependent loss is made by the technology of strong fused biconical taper,and the second order mode coupler with 0.3 dB polarization dependent loss is made by the technology of weak fused biconical taper.By combining the nonlinear polarization rotation mode-locking mechanism,OAM mode femtosecond fiber laser with over 100 MHz repetition rate is built.The achievement of the key parameters is attributed to the selection of dispersion shifted fibers that can accurately adjust intracavity dispersion.Comparing with traditional dispersion compensation fibers(DCF),the group velocity dispersion is reduced by an order of magnitude,so it can better adjust intracavity dispersion to achieve the indexes of large spectral bandwidth and narrow pulse width.In addition,the diameter of the fiber is 8 μm,which is the same as that of a single mode fiber.Comparing with DCF,the fusion loss can be ignored,so only a shorter gain Erbium-doped fiber is required,which ensures a shorter overall cavity length and achieves high repetition frequency.The experimental results show that the first order OAM mode fiber laser has 113.6 MHz repetition rate,98 fs half-height full pulse width,and 101 nm10 dB bandwidth.Second-order OAM mode fiber laser has 114.9 MHz repetition rate,60 fs half-height full pulse width,and 100 nm 10 dB bandwidth.Compared wi

关 键 词：光纤锁模激光器 轨道角动量 模式耦合器 

分 类 号：TN248[电子电信—物理电子学]