Giant-chirp oscillators for short-pulse fiber amplifiers.

A new regime of pulse parameters in a normal-dispersion fiber laser is identified. Dissipative solitons exist with remarkably large pulse duration and chirp, along with large pulse energy. A low-repetition-rate oscillator that generates pulses with large and linear chirp can replace the standard oscillator, stretcher, pulse-picker, and preamplifier in a chirped-pulse fiber amplifier. The theoretical properties of such a giant-chirp oscillator are presented. A fiber laser designed to operate in the new regime generates approximately 150 ps pulses at a 3 MHz repetition rate. Amplification of these pulses to 1 microJ energy with pulse duration as short as 670 fs demonstrates the promise of this new approach.