In this paper, we propose an EADO-OFDM (Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing) method for IM/DD (Intensity-Modulated DirectDetection) optical systems, in which the AV-DCO-OFDM (Absolute Valued DC Biased Optical OFDM) symbols on the even subcarri