We propose the use of cross-gain modulation (XGM) for multichannel NRZ-to-RZ data format conversion in a single semiconductor optical amplifier (SOA). Four 10Gbls WDM NRZ signals are converted simultaneously to RZ format without logic inversion. The proposed technique is advantageous over previous schemes due to its particular simplicity, polarization independency, and wavelength-shift-free operation. It maintains good performance under 16.5dB input power dynamic range, and large time and wavelength offsets between input signals and control clock.978-1-4673-4352-7/12/$31.00 ©2012 IEEE