Wavelength conversion of a 10 Gb/s 2.7%-duty-cycle return-to-zero (RZ) OOK (RZ-OOK) signal using XPM in a compact silicon nanowire waveguide (Si nanowire) and a detuned filter is successfully demonstrated for the first time. A 10 -9-BER receiver sensitivity penalty of <1dB was measured for the converted signal relative to the baseline signal, with a filter-probe detuning of 0.6nm. The system is numerically modeled and the results are shown to match well with the experimental results. The numerical model is further used to design an optimal filter that would eliminate filter-probe detuning. © 2010 IEEE.