Modeling and optimization of low-repetition-rate high-energy pulse amplification in cw-pumped erbium-doped fiber amplifiers

Abstract

We numerically study amplification of low-repetition-rate high-energy pulses in a cw-pumped erbium-doped fiber amplifier. Maximizing the pulse-energy gain by optimization of the dopant and modal field radii resulted in improvements of as much as 7.3 dB with a 60-mW pump compared with a fiber with small radii suitable for amplification of cw signals. Output pulse energies of 0.15 mJ are possible at the same pump power. The improvements stem from a suppression of the losses from amplified spontaneous emission when the radii are made large.