A full-duplex radio-over-fiber(ROF) system with optical millimeter wave generation is proposed based on a novel single-sideband(SSB) by an external modulator.By properly biasing the intensity modulator,the repetitive frequency of the double-sideband(DSB) signal is four times of the RF singal frequency.After the central carrier was filtered by a FBG and modulated with baseband data at 2.5 Gb/s,it was recombined with the unmodulated second-order signal to generate optical millimeter wave by an opt...