Using the moment generating function for the performance assessment of optically preamplified direct-detection OFDM systems

A new method based on the moment generating function (MGF) is proposed to evaluate the performance of an orthogonal frequency division multiplexing (OFDM) system with optical preamplification and direct-detection at the optical receiver, which takes into account arbitrary optical and electrical filtering at the optical receiver. The accuracy of the proposed method is investigated by comparison of the bit error probability obtained from the MGF with the estimates obtained from Monte Carlo simulation, for different electrical filter types with various bandwidths and for a different number of OFDM subcarriers. It is shown that the proposed method has a good accuracy, for bandwidths of the electrical filter typically used in optical OFDM systems (larger than the OFDM signal bandwidth).