Enhanced asymmetrically clipped DC biased optical OFDM for intensity-modulated direct-detection systems

摘要

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 subcarriers and ACO-OFDM (Asymmetrically Clipped Optical OFDM) symbols on the odd subcarriers are combined for simultaneous transmission.Moreover,we discuss the PDF (Probability Density Function) and electrical SNR (Signal to Noise Ratio) of the symbols,which are utilized to estimate the BER (Bit Error Ratio) performance and overall performance of EADO-OFDM.The Monte Carlo simulation results have validated the theoretical analysis and have also confirmed the EADO-OFDM is attractive considering the following benefits.Firstly,EADO-OFDM is more energy efficient compared to the power-efficient DCO-OFDM (DC Biased Optical OFDM),since the required DC bias is smaller when appropriate constellation size combinations are chosen.In addition,EADO-OFDM performs better than the conventional ADO-OFDM (Asymmetrically Clipped DC Biased Optical OFDM),because the absolute value operation causes no clipping distortion.