Investigation of generation and transmission performance of millimeter-wave based on single-sideband modulation

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 optical coupler with a centain coupling coefficient and transmitted to the base station over a single-mode fiber.The central carrier and one of the second sidebands were beaten to generate the millimeter wave while the other second sideband was reused as carrier for uplink connection.The dispersion performance of the generated mm-wave was theoretically analyzed.The experimental results show that the eye diagrams of uplink and downlink singals are open clearly after transmission over 50 km fiber,and the system can reduce the fading effect caused by fiber dispersion and is immune to the walk-off of conventional single-sideband singal effectively.Therefore,it is suitable for long distance transmission.