Two-photon absorption and free-carrier effects in semiconductor optical amplifier

This paper presents the carried out investigation on nonlinear effects in semiconductor optical amplifier (SOA); in particular two-photon absorption process and its induced free carriers. The simulation results show nonlinear phase shift and the spectral broadening is induced by nonlinear free-carrier effect after propagation through the SOA. The levels of injected carrier density in SOA are varied to find the minimum BER. It is observed that increasing the injection current will result in better BER as the injected current increases until 1A, the quality of eye pattern is better and widely open with minimum recorded BER is 0.