超快光纤激光器中可控脉冲产生与湮灭动力学  

Controlled pulse generation and annihilation dynamics in ultrafast fiber lasers

作　　者：周瑞 李阳[1] 朱润徽 张祖兴[1] Zhou Rui;Li Yang;Zhu Run-Hui;Zhang Zu-Xing(School of Electronic and Optical Engineering,School of Flexible Electronics(Future Technology),Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院,南京210023

出　　处：《物理学报》2024年第17期161-168,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62175116)资助的课题.

摘　　要：本文采用实时傅里叶变换光谱探测技术,研究了基于泵浦强度调制的超快光纤激光器中锁模脉冲产生与湮灭动力学过程.结果表明:当泵浦调制电压处于高电平时,激光器输出稳定的锁模脉冲.随着调制电压跳变至低电平,锁模脉冲的强度不断降低,而后经历一段衰减振荡阶段后发生湮灭,在~5μs后孤子从噪声中重建,这一过程伴随着调Q不稳定性的产生.在低电平阶段,激光腔内的湮灭过程连续发生,其周期为~55μs.通过改变调制泵浦的占空比,能够操控在低电平调制下孤子连续湮灭的次数.进一步,锁模与孤子湮灭的连续切换过程与泵浦调制频率有关,调制频率的升高能够有效缩短两种状态的持续时间从而减少孤子湮灭的次数.此外,通过减小低电平的值,能够降低激光腔内的增益,使得孤子连续湮灭的周期缩短.研究结果有利于深入了解孤子的形成与湮灭动力学,并为超快激光器各种运行机制的发展提供了新的视角.In this paper,the mode-locked pulse generation and annihilation dynamics in ultrafast fiber lasers based on pump intensity modulation are investigated by using real-time Fourier transform spectral probing.The results show that the laser outputs stable mode-locked pulses when the pump modulation voltage is at a high level.As the modulation voltage jumps to a low level,the intensity of the mode-locked pulse decreases,and then undergoes a period of decaying oscillation before annihilation occurs,and after~5μs the soliton is reconstructed from the noise,accompanied by the generation of the Q-modulation instability.In the low-level phase,the annihilation process in the laser cavity occurs continuously with a period of~55μs.By changing the duty cycle of the modulation pump,it is possible to control the the number of times solitons continuously annihilate under low-level modulation.Further,the continuous switching process of mode-locking and soliton annihilation is related to the modulation frequency of the pump,and the increase of the modulation frequency can effectively shorten the duration of the two states,thus reducing the number of soliton annihilations.In addition,by reducing the value of the low level,the gain in the laser cavity can be reduced,resulting in a shorter period of successive soliton annihilation.The results of the study are conducive to an in-depth understanding of the formation and annihilation dynamics of solitons,and provide new perspectives for developing various operation mechanisms of ultrafast lasers.

关 键 词：泵浦强度调制 孤子湮灭 脉冲状态切换 色散傅里叶变换 

分 类 号：TN248[电子电信—物理电子学]