All-Optical Picosecond Signal Processing in a M-Z Interferometer Based on a Multi-Section Semiconductor Optical Amplifier

New features of the cross-gain modulation and the cross-phase modulation in a nonlinear active device, made by a cascade of differently biased semiconductor optical amplifiers, have been numerically investigated and discussed. In the frame of an interferometric application, the performances of a 4 times 25 Gb/s all-optical demultiplexer based on such a multi-section amplifier have been derived. This new nonlinear amplifier has been revealing able to manipulate 1 ps FWHM optical Gaussian pulses both in terms of their amplitude and phase, without introducing any unwanted distortion in the extracted channel. The demultiplexed signal has shown a significant amplification, an excellent extinction ratio, and no degradation due to the optical gain pattern- dependence in the nonlinear multi-section amplifier.