Wang Xiaocong, Wang Benhai, He Wenbin, Zhang Xintong, Huang Qi, Huang Zhiyuan, Jiang Xin, Pang Meng, Russell Philip St J
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, 230026, China.
Russell Centre for Advanced Lightwave Science, Shanghai Institute of Optics and Fine Mechanics and Hangzhou Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.
Light Sci Appl. 2025 Feb 2;14(1):66. doi: 10.1038/s41377-024-01736-3.
Harmonic mode-locking, realized actively or passively, is an effective technique for increasing the repetition rate of ultrafast lasers. It is critically important to understand how a harmonically mode-locked pulse train responds to external perturbations and noise, so as to make sure that it is stable and resistant to noise. Here, in a series of carefully designed experiments, we elucidate the retiming dynamics of laser pulses generated in a soliton fiber laser harmonically mode-locked at GHz frequencies to the acoustic resonance in a photonic crystal fiber (PCF) core. We characterize the self-driven optomechanical lattice, which is distributed along the PCF and provides the structure that supports harmonic mode-locking, using a homodyne setup. We reveal that, after an abrupt perturbation, each soliton in the lattice undergoes damped oscillatory retiming within its trapping potential, while the retiming is strongly coupled to soliton dissipation. In addition, we show, through statistical analysis of the intra-cavity pulse spacing, how the trapping potentials are effective for suppressing timing jitter. The measurements and the theory developed in this work lay the groundwork for studies of the general stability and noise performance of harmonically mode-locked lasers as well as providing valuable insight into generic multi-pulse phenomena in mode-locked lasers.
主动或被动实现的谐波锁模是提高超快激光器重复频率的有效技术。了解谐波锁模脉冲序列如何响应外部扰动和噪声至关重要，以确保其稳定且抗噪声。在此，在一系列精心设计的实验中，我们阐明了在千兆赫兹频率下谐波锁模的孤子光纤激光器中产生的激光脉冲与光子晶体光纤（PCF）纤芯中的声共振的重定时动力学。我们使用零差设置对沿PCF分布并提供支持谐波锁模结构的自驱动光机械晶格进行了表征。我们发现，在突然扰动之后，晶格中的每个孤子在其捕获势内经历阻尼振荡重定时，而重定时与孤子耗散强烈耦合。此外，我们通过对腔内脉冲间距的统计分析表明，捕获势如何有效地抑制定时抖动。这项工作中的测量和理论为研究谐波锁模激光器的一般稳定性和噪声性能奠定了基础，同时也为锁模激光器中的一般多脉冲现象提供了有价值的见解。
