Direct Current Bias Optimization of the LDPC Coded DCO-OFDM Systems

In this letter, a direct current (DC) bias optimization scheme is proposed for the low-density parity-check (LDPC) coded DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) systems from consideration of power efficiency and dimming control. The DC bias can be optimized subject to the decoding convergence threshold, which is calculated by the extrinsic information transfer (EXIT) chart analysis for the LDPC coded DCO-OFDM systems. The simulations demonstrate that the decoding performance with different DC bias is quite consistent with the numerical results after the EXIT chart analysis.