Signal integrity of femtosecond pulses patterns in a 500Gb/s all-optical demultiplexer for otdm interconnections by using nonlinearities in semiconductor optical amplifiers

This paper numerically investigates the problematic of preserving the signal integrity in a board equipped with Semiconductor Optical Amplifiers (SOAs), optically interconnected to perform optical signal demultiplexing at several hundreds of Gb/s. First, the extreme features of the nonlinear optical gain saturation dynamics in SOAs inputted with dense femtosecond optical pulses signals have been derived by means of a proper theoretical model, suitable for calculating - in a self-consistent way - the quasi-Fermi levels and the carriers temperatures from the instantaneous values of the carrier density and the energy densities in both valence and conduction bands. Then, the results obtained have been used to investigate the potential performances of an interferometric SOA-based pump-probe scheme working as an all-optical ultrafast demultiplexing structure. Simulations have revealed how, with a proper management of the SOAs nonlinear optical gain dynamics, this architecture could extract any 100 Gb/s channel from a 500 Gb/s pattern, with a high value of its extinction ratio, a negligible amount of optical losses, and no degradation due to the SOA optical gain pattern dependence.