In this paper, a novel interference suppression technique from added RoF (Radio-on-Fiber) system is proposed. In general RoF system, received RF (radio frequency) signal intensity is periodically varied depending on chromatic dispersion that is known as fading phenomenon. In proposed technique null points of this fading phenomenon are intentionally applied to minimize signal interferences. This technique can realize two types of multiplexing RoF signal. In the first configuration, a single optical carrier is modulated twice using two optical modulators connected in series. In second configuration, new RoF signal is added to the existing network using individual light source. Multiplexing RoF signals of 10GHz-band with data of 30Mbps 64QAM is experimentally demonstrated.