Abstract: A photon up-conversion system was proposed based on low-rate RZ-OOK signal injected into the Fabry-Perot cavity laser diode(FP-LD) without local oscillator. External injected optical signal locked one of FP-LD free oscillation mode, a high-frequency microwave oscillation was generated, and the injection locking mechanism of the up-conversion principle was analyzed, and experimentally verified the feasibility of the scheme. In the experiments, the 2 Gb/s RZ-OOK signal was respectively converted into 12 GHz and 14.28 GHz subcarrier signals.