Generation of H-shaped pulse rains induced by intracavity Fabry–Perót filtering in a fiber laser

• Published in: Optical fiber technology Vol. 61; p. 102453
• Main Authors: He, Yinbin, Li, Mengxian, Shu, Yiqing, Ning, Qiuyi, Chen, Weicheng, Luo, Aiping
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.2021
• Subjects: Fiber laser; H-shaped pulse; Pulse rains; H-shaped pulse; Fiber laser; Pulse rains
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2021.102453

•The first experimental observation of h-shaped pulse rain.•Intracavity filtering induced the generations of h-shaped pulses and rains.•The detail physical mechanism description of h-shaped pulses and rains. We report the generation of h-shaped pulses and rains in a fiber laser with a Fabry–Perót (F–P) subcavity. An h-shaped pulse state composed of a sharp spike as a leading edge and a long flat-top bunch as a tailing one could be switched to an h-shaped pulse rain state by adjusting the polarization controllers (PCs). F–P filtering was found to play a crucial role in the formation of the h-shaped pulses and rains. The leading and tailing edges of the h-shaped pulse were found to be generated in the primary and secondary F–P filtering profiles, respectively. Furthermore, small discrete pulses could be triggered in the subordinate longer-wavelength F–P filtering profiles by adjusting the PCs. Then, for the first time, h-shaped pulse rains were experimentally observed as many small pulses continuously drifting away from the nanosecond-long h-shaped pulses because of their group velocity mismatch. These results will help contribute to a deep understanding of the dynamics of complex pulse patterns in fiber lasers.