To generate millimeter-wave signal using optical method, a optical frequency multiplication (OFM) system was constructed with a phase modulator and a fiber periodic filter. The periodic filter was made of two polarizers and a segment of birefringent fiber. The theoretical analysis shows that in this system the unexpected odd/even harmonic components can be suppressed effectively by adjusting the birefrigent fiber delay. Furthermore, the desired electrical harmonics can be given prominence to the others by optimizing the phase modulation index. The simulation results demonstrate that the 60 GHz millimeter-wave signal can be effectively generated, and 2.5 Gbps NRZ signals can be correctly transmitted in this OFM system. The theoretical and simulation results also indicte that the OFM system based on the sinusoidal-signal phase modulation should be analyzed using the harmonious optical sidebands, instead of the sweeping frequency theory.