Probe signal dependence of XPM wavelength converters

Wavelength conversion makes WDM networks efficient and have high capacity. A wavelength converter using cross phase modulation (XPM) is preferred because of small chirp and high efficiency. However, SOAs used for XPM generate excess noise, i.e. amplified spontaneous emission (ASE) noise. ASE noise is larger than other noises such as shot noise and thermal noise, and dominant cause of the power penalty in wavelength conversion. Considering a cascadability wavelength converter for WDM networks, a good quality of the signal after conversion is important. In this paper, the quality of the wavelength converted signal is investigated for probe power variation.