Abstract : We have systematically designed and realized the optical feedforward transmitter using microwave circuit model of distributedfeedback laser diode (DFB LD) based on rate equations. Through the system-level simulation for the optical feedforward method, the nonlinearity of DFB-LD is analyzed, and the optimized characteristics of the RF components in the system are confirmed by using a microwave simulator. The experimental and simulated results show the reduced distortion products and enhanced spurious-free dynamic ranges are in good agreement at 2.4 GHz. These results are analyzed as the evaluation parameters for the miniaturization and optimization of the feedforward compensation method in radio-over-fiber systems.