Nonlinear chirped pulse amplification for a 100-W-class GHz femtosecond all-fiber laser system at 1.5 μm

作者：Fan, Yiheng; Xiu, Hao; Lin, Wei; Chen, Xuewen; Hu, Xu; Wang, Wenlong; Wen, Junpeng; Tian, Hao; Hao, Molei; Wei, Chiyi; Wang, Luyi; Wei, Xiaoming^*; Yang, Zhongmin^*

来源：High Power Laser Science and Engineering, 2023, 11: e50.

DOI：10.1017/hpl.2023.36

• high-power femtosecond fiber laser
• high repetition rate
• intermodal modulational instability
• nonlinear pulse compression

In this work, we present a high-power, high-repetition-rate, all-fiber femtosecond laser system operating at 1.5 mu m. This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz with an average output power of 106.4 W - the highest average power reported so far from an all-fiber femtosecond laser at 1.5 mu m, to the best of our knowledge. By utilizing the soliton-effect-based pulse compression effect with optimized pre-chirping dispersion, the amplified pulses are compressed to 239 fs in an all-fiber configuration. Empowered by such a high-power ultrafast fiber laser system, we further explore the nonlinear interaction among transverse modes LP01, LP11 and LP21 that are expected to potentially exist in fiber laser systems using large-mode-area fibers. The intermodal modulational instability is theoretically investigated and subsequently identified in our experiments. Such a high-power all-fiber ultrafast laser without bulky free-space optics is anticipated to be a promising laser source for applications that specifically require compact and robust operation.