Abstract : Although the field applications of conventional optical feedforward transmitters were limited due to stationary transmission distance, the proposed optical feedforward transmitter overcame the limitations using vector control theory. A vector control circuit achieved perfectly the third-order intermodulation (IMD3) suppression regardless of distance or dispersion. The experimental results show that the IMD3 for two-tones was suppressed by maximum 38 dB even after 20 km. This work shows that the proposed optical feedforward transmitter is applicable to optical fiber radio transmission system.