Numerical Study of Parabolic Pulse Generation in Backward-Pumped Erbium-Doped Fiber Amplifiers

In this paper, the actual shape of the gain spectrum and the whole dispersion curve of the Er-doped fiber are employed in the vectorial coupled nonlinear Schrödinger equation to model the parabolic pulse (similariton) generation in the backward-pumped Er-doped fiber amplifier. The input of the amplifier is Gaussian pulses of a high repetition rate. The numerical model is developed to account for the combination of input and amplified spontaneous emission powers to consider the average of all prior iterations in the present interaction to reach a converged solution rather than oscillating between two solutions. The excess kurtosis factor identifies the parabolic pulse among other pulse shapes. The effect of the input pulse width, peak power, and polarization and the impact of the input pump power and the fiber length on the similariton generation are studied.