Abstract: High -speed photonic signal source is absolute necessity for modern optical communications, which attracts more and more attention at present. By using a biased Mach-Zehnder modulator (MZM), a simple scheme based on frequency multiplication was presented and experimentally investigated for generation of high-speed microwave photonic signal. The phase difference of two beams in the MZM was adjusted by a DC bias applied on the MZM, which caused pulse splitting and frequency multiplication. In the experiment, a 5 -GHz RF signal source successfully generated double -frequency microwave optical signal (10-GHz) with great quality. It was also observed that different biased voltage would produce different pulse train, while the optimal bias was required for high -quality frequency multiplication. This scheme is available to generate high-frequency optical pulses over 40 GHz, which is promising to be widely used in microwave photonic communication.