基于可饱和吸收体锁模激光器中的呼吸子  

Breathers in mode-locked lasers based on saturable absorbers

作　　者：侯刘敏 侯云龙 刘圆凯 李渊华 林佳 陈险峰 HOU Liumin;HOU Yunlong;LIU Yuankai;LI Yuanhua;LIN Jia;CHEN Xianfeng(College of Mathematics and Physics,Shanghai University of Electric Power,Shanghai 201306,China;State Key Laboratory of Advanced Optical Communication Systems and Networks,School of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Research Center for Quantum Sciences,Shanghai 201315,China;Collaborative Innovation Center of Light Manipulation and Applications,Shandong Normal University,Jinan 250358,China)

机构地区：[1]上海电力大学数理学院,上海201306 [2]上海交通大学物理与天文学院,区域光纤通信网与新型光通信系统国家重点实验室,上海200240 [3]上海量子科学研究中心,上海201315 [4]山东师范大学,光操纵与应用协同创新中心,济南250358

出　　处：《物理学报》2025年第4期146-152,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12074155,62375164)资助的课题.

摘　　要：呼吸子作为一种独特的非线性脉冲现象,在激光器性能优化、非线性光学过程研究以及复杂信号传输中发挥着关键作用.与稳定孤子不同,呼吸子脉冲的能量随着时间发生周期性波动,表现为脉冲频率和振幅的周期性变化.通过适当的非线性效应,激光器能够产生稳定的呼吸子脉冲,实现呼吸锁模状态,展现出类似“呼吸”的周期性模式.基于此,本文设计并搭建了一台基于可饱和吸收体作为锁模元件的光纤激光器,并在较低泵浦功率下成功观察到稳定的呼吸态.通过利用高速探测技术和时间拉伸色散傅里叶变换(TS-DFT)技术,对快速脉冲进行了时间放大和频谱分析,并实时监测呼吸子脉冲在时域和频域上的演化过程.实验结果表明,泵浦功率的变化显著地影响附加振荡引发的周期性调制,从而调控呼吸比,直至形成稳定的孤子.当泵浦功率达到470—480 mW时,实验首次观察到呼吸子的形成,其呼吸比高达4.5.随着泵浦功率的增加,呼吸效应逐渐减弱,并在510 mW时完全消失,呼吸比降至1.这一结果验证了泵浦功率对呼吸子状态及其转变过程的关键控制作用,为超快激光技术和非线性光学领域提供新视角.Breathing pulses,as a unique nonlinear pulse phenomenon,play a key role in optimizing laser performance,nonlinear optical processes,and complex signal transmission.Unlike stable solitons,the breathing pulses fluctuates in energy periodically with time,and both pulse frequency and amplitude exhibit periodic changes.Through appropriate nonlinear effects,lasers can generate stable breathing pulses,achieving a mode-locked state that exhibits a periodic“breathing”pattern.Based on this,a fiber laser combining a saturable absorber as the mode-locking element is designed and built,and stable breathing states are successfully observed at lower pump power levels.High-speed detection techniques and time-stretched dispersive Fourier transform(TS-DFT)technology are used to time-amplify and spectrally analyze the rapid pulses,while monitoring the evolution of the breathing pulse in both time domain and frequency domain.Experimental results indicate that the change in pump power significantly affects the periodic modulation induced by additional oscillations,thereby controlling the breathing ratio and ultimately resulting in the formation of a stable soliton.When the pump power is between 470 and 480 mW,the formation of the breathing pulse is first observed,with a breathing ratio of up to 4.5.As the pump power increases,the breathing effect gradually diminishes,and at 510 mW,it completely disappears,with the breathing ratio dropping to 1.These results confirm the critical role of pump power in controlling the breathing pulse state and its transition,demonstrating the potential of controlling pump power in ultrafast laser technology and nonlinear optics.The breathing pulse phenomenon,as a periodic pulse behavior,reflects the complex dynamical characteristics between nonlinear optical effects and cavity parameters.Combined with the natural synchronization system formed between the breathing frequency and the cavity frequency(determined by the cavity length),the periodic change of the breathing pulse becomes a crucial factor f

关 键 词：激光器 呼吸子 非线性光纤动力学 

分 类 号：TN248[电子电信—物理电子学]