A full-duplex radio-over-fiber (ROF) system through an optical phas e modulation(OPM) and a fiber Bragg grating (FBG) filter generating quadrupling-frequency optical millimeter-wave is proposed and analyzed theoretically.At central station,the system applies the mixed-frequency signals with base-band signals and radio frequency(RF) signals to drive an OPM,and then multiple-sideband optical signal with suppressed fir st-order sideband is generated.After transmission over fiber,the FBG filter is used to obtain the optical sig nal with quadrupling frequency at base station. The simulation results show that the downstream signal is visible on eye diagram s after 40km fiber transmission with less than 1.6dB power penalty.In this new scheme,the configuration of the base stat ion is further simplified because there is no additional laser,at the same time the frequency of RF signal is reduced due to frequency quadrupling.The cost of the new system is largely reduced.