A scheme of millimeter (mm)-wave generation utilizing one phase modulator (PM) has been proposed experimentally. To generate a mixing signal, the baseband signal is mixed with the radio frequency (RF) signal using an electric mixer. And the double-sideband (DSB) signal generated from phase modulator which is drived by the mixing signal is transmitted to base station along an optical fiber. The central carrier and the first-order sideband are separated by an optical interleaver (IL) at base station. The first-order sideband signals are beaten to generate the mm-wave with a double repetitive frequency of the RF signal when they are detected by an optical receiver, and the central optical carrier can be reused as carrier for uplink connection. The transmission performance of the mm-wave is analyzed. The duty cycle of the code decreases as the transmission distance increases because of the different delay of the first-order sidebands caused by fiber dispersion. And it limits the lagest transmission distance of the mm-wave. In the experiment, the 20 GHz RF signal generates 40 GHz mm-wave and 2.5 Gbit/s non-return-zero (NRZ) is carried by mm-wave. For downlink connection, the power penalty is 0.2 dBm after data transmit over 20 km dispersive fiber.