Noise characterisation of wavelength converters based on XGM in SOAs

Wavelength conversion (WC) has recently emerged as an important technique that can be used to manage the spectacular increase of traffic in DWDM networks. WC is extremely useful for solving contention and reducing wavelength blocking and a wide range of WC methods have been reported. The optimum placement of these devices within a network remains an unexplored area and accurate models to measure the performance of the system are becoming vital. This paper presents an original noise characterisation of a class of WCs based on cross gain modulation (XGM) in semiconductor optical amplifiers (SOAs). A new expression for the error probability (P_e) is presented offering considerable additional accuracy in sensitivity measurement compared with the Gaussian approach. Simulation comparisons are presented in different scenarios for a standard system working at 2.5 Gb/s in a metropolitan area network