Simulation on the evolution of spectrum-managed optical pulse propagation in active fibers with programmable gain spectral profile

Erbium-doped fiber lasers have become a reliable source of sub-100 fs pulses at 1550 nm; however dispersion and nonlinearities in optical fiber make generation of multi-nJ pulses difficult. In this paper a two-stage fiber amplification system which consists of two sub-fiber-amplifiers was designed by introducing a filter between the two sub-amplifiers to manage or modify the spectrum of the pulse amplified by the first sub-fiber-amplifier before it goes into the second one. A systematic simulation, both in time domain and in frequency domain, for this fiber amplifier system was conducted. The role of the filter in the system is presented and discussed. The parameters of this two-stage fiber amplification system are determined by calculation results based on the high-concentration Er-doped fiber as gain media and high power laser diodes as pump light sources, All of the components in the system are commercially available. In addition, the optimal output of the amplification system was obtained based on simulations.