© 1983-2012 IEEE. A new time-domain wideband numerical model for simulation of quantum dot-reflective semiconductor optical amplifier (QD-RSOA) steady-state and dynamic behavior, is described. The model is used to investigate 1 ps full-width at half-maximum input Gaussian pulse amplification and also modulation cancellation. A large modulation-cancellation dynamic range of about 35 dB, is predicted for high input powers, which is not attainable in bulk and QW RSOAs. The model can be applied to traveling-wave and reflective QD-SOAs. The combination of the unique features of quantum dots and a reflective structure can be used to realize a colorless modulator for wavelength-division multiplexed passive optical networks (WDM PONs).