This paper investigates microcomb dynamics in a fiber-based Fabry-Perot microresonator with ultra-small anomalous GVD. Experimentally, they achieved 2/3-octave-spanning microcombs with ~10 GHz spacing, >84 THz span, and >8400 comb lines in the modulational instability (MI) state. They also observed anomalous-dispersion based near-zero-dispersion solitons (AD-NZDS) with a local repetition rate up to 8.6 THz, pulse duration <100 fs, span >32 THz, and >3200 comb lines. Broadband MI combs offer high conversion efficiency and wide range, while AD-NZDS exhibit low phase noise and ultra-high repetition rate.

Zeyu Xiao, Tieying Li, Minglu Cai, Hongyi Zhang, Yi Huang, Chao Li, Baicheng Yao, Kan Wu, Jianping Chen