Synchronized Two-Color Mode-Locked Fiber Laser Source With GHz Repetition Rate

• Published in: Journal of lightwave technology 2024-01, Vol.42 (2), p.802-808
• Main Authors: Liang, Chao, Zhu, Zhe, Lin, Wei, Wang, Wenlong, Chen, Xuewen, Wei, Chiyi, Gao, Zihan, Wang, Luyi, Liang, Zhaoheng, Ling, Lin, Wei, Xiaoming, Yang, Zhongmin
• Format: Article
• Language: English
• Subjects: Color; Erbium; Fiber lasers; Four-wave mixing; GHz repetition rate; Holes; Laser cavities; Laser mode locking; Laser stability; Lasers; multi-color ultrashort pulses; Optical fiber amplifiers; Optical fiber couplers; Oscillators; Phase locked loops; Repetition; Short fibers; Synchronism; Synchronization; Timing jitter; Transient response; ultrafast fiber laser; Ytterbium
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2023.3319370

Multi-color ultrashort pulses with GHz repetition rates are promising for spectroscopic and four-wave-mixing-based applications that specifically require both fast transient response and fast refresh rate. Among existing technologies for generating multi-color ultrashort pulses, actively synchronizing multiple lasers operating at different wavelengths advances in the technical simplicity, and shows a high coherence. However, for GHz repetition rates, the short cavity design, on one hand, is sensitive to environmental perturbations that change the cavity length (thus the repetition rate); on the other hand, it challenges the active repetition-rate synchronization by adding extra free-space components. In this work, we demonstrate long-term stable synchronization between a Yb-doped GHz-repetition-rate mode-locked fiber laser and an Er-doped GHz-repetition-rate mode-locked fiber laser. The stable active synchronization is realized by using the phase-locked-loop technology that is implemented for short fiber cavities. The repetition rates of the two short fiber laser cavities can be stably locked with millihertz precision and a timing jitter of about 20 fs.