High-repetition-rate

high-power

ultrashort pulse fiber lasers are highly attractive and promising light sources in various fields of high-precision scientific research and industrial applications. Here

we demonstrate a compact Yb-doped soliton oscillator gain-managed nonlinear amplifier (SO-GMNA) system that delivers pulses at a fundamental repetition rate of 171 MHz with an average power of 8.26 W

compressible to 40.8 fs. The use of an intracavity chirped fiber Bragg grating enables direct generation of chirp-optimized

sideband-free soliton pulses suitable for the subsequent GMNA stage

which substantially simplifies the system structure and enhances its robustness. Leveraging this system

we further explored the intriguing noise characteristics and spectral coherence evolution during the nonlinear amplification processes. Our findings offer valuable insights for the development of cost-effective

highly reliable

and high-performance ultrashort fiber laser systems.