All-optical technique for modulation format conversion from on-off-keying to alternate-mark-inversion

We propose and numerically investigate for the first time a novel all-optical on-off-keying to alternate-mark-inversion modulation format converter operating at 40 Gbps employing a semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI). We demonstrate that this SOA-MZI operates as a pulse subtractor, and in the absence of patterning will produce perfectly phase inverted pulses regardless of the individual SOA phase excursions. We use a comprehensive computer model to illustrate the impact of patterning on the output phase modulation, which is quantified through the definition of the phase compression factor.