Chirp in a wavelength converter based on a symmetrical-MZI employing SOAs

A wavelength converter based on cross-phase modulation using semiconductor optical amplifiers (SOAs) in a symmetrical MZI is modelled. Since the model of the SOAs considers both amplitude and wavelength-dependent parameters simultaneously it provides an accurate prediction of the peak chirp variation for both inverting and non-inverting converted probe signals. The peak chirp variation and the eye-opening ratio are determined for ITU-T grid wavelength up- and down-conversion and they show a sharp dependence on the injection current of the SOAs. Optimal operating conditions for the wavelength converter are demonstrated in order to achieve nominal chirp on the output signal for either an inverting or non-inverting converted probe signal.