Nonlinear propagation and wave mixing characteristics of pulses in semiconductor optical amplifiers

Nonlinear propagation and wave mixing characteristics of pulses in semiconductor optical amplifiers (SOAs) are analyzed using the finite-difference beam propagation method (FD-BPM). From the analyzed output waveform it is found that the peak positions of pulses are shifted to the leading edge. The output spectra are red-shifted and the dips are found at the higher frequency side in the frequency spectra. Two pulses propagate in SOAs and four-wave mixing (FWM) characteristics are obtained. Next, all-optical demultiplexing (DEMUX) characteristics of pulses in SOAs based on Fill are analyzed. From this analysis, it is clear that the SOAs with wider gain bandwidth are required for faster DEMUX operation. The DEMUX characteristics from the time-multiplexed signals by the repetitive pump pulses are also analyzed. The FWM signal intensity decreases with the strong pump pulses. However, there is no pattern effect due to gain saturation of pulses, because the pump pulses are injected continuously. (C) 2008 Wiley Periodicals, Inc.