Generation of 98-W, 392-µJ, 35-fs pulses from double-pass Yb‑fiber CPA system incorporating CFBG‑enabled spectral pre‑shaping and nonlinear post-compression

Abstract We present a high‑power Yb‑fiber chirped‑pulse amplification (CPA) system incorporating a chirped fiber Bragg grating for passive spectral pre‑shaping. The compact double‑pass CPA system delivers 414-µJ, 270-fs pulses at 250 kHz (103.5-W average power) with a net gain of 39.3 dB. To further shorten the pulse duration, a multi‑pass cell (MPC) is employed for nonlinear post‑compression, achieving 35-fs pulses with ~95% throughput efficiency and 98-W average power. This double-pass CPA system equipped with high‑efficient MPC post‑compression offers a scalable and robust route to high‑energy ultrafast driving sources for high-harmonic generation.