High-Peak-Power Ultrashort Pulse Generation Using All-Fiber Chirped Pulse Amplification System with Small Core Multimode Fiber

Abstract

We present an all-fiber chirped pulse amplification system based on a normally dispersive single mode Er-doped fiber and a multimode fiber of 25 µm core diameter. The 260 fs sech2 transform-limited pulses generated in a passively mode-locked Er-doped fiber laser are stretched to 1 ps and amplified in an Er-doped fiber amplifier. Then the subsequent multimode fiber in which the pulses propagate only in the fundamental mode compresses the pulses to 80 fs. The pulse compression using the conventional multimode fiber as a large-core single-mode fiber is demonstrated for the first time. The peak power of the output pulses is increased to 44 kW.