Dual-pass Pre-chirp managed amplification with high gain and high average power

We demonstrate the first dual-pass pre-chirp managed amplification in a rod-type Yb-fiber that amplifies 23-mW broadband pulses to 101.5-W with 36.5-dB gain. After compression, the system delivers 2-μJ, 67-fs pulses.

Recent work has shown that dual-pass rod-type fiber amplifiers feature high gain (>40 dB) and therefore can amplify weak seeding pulses with the average power as low as 10 mW [1]. Such an a feature is attractive because it allows to construct a high-power femtosecond source in a compact configuration. To date, all the demonstrated dual-pass fiber amplifiers are seeded either by narrowband picosecond pulses to study the power scalability or by strongly stretched broadband pulses to achieve chirped-pulse amplification (CPA). In this submission, we demonstrate pre-chirp managed amplification (PCMA) in a dual-pass rod-type Yb-fiber amplifier. PCMA is a nonlinear amplification technique that allows generation of μJ-level pulses with the duration well below 100 fs. For example, we demonstrated that circular polarization based PCMA in a single-pass rod-type fiber can deliver 2-μJ, 47-fs pulses with 101-W average power [2]. However, due to a relatively small gain associated with single-pass fiber amplifier, the required Watt-level seeding pulses were obtained from a complicated Yb-fiber CPA system. In this submission, we implement the first dual-pass PCMA (DP-PCMA) system, which, thanks to the high dual-pass gain of 36.5 dB, amplifies 23-mW broadband pulses up to >100 W. The amplified pulses are compressed down to 67 fs in duration.