Subcarrier index-power modulated optical OFDM with dual superposition multiplexing for IMDD PON systems

A signal transmission technique termed subcarrier index-power modulated optical orthogonal frequency division multiplexing with dual superposition multiplexing (SIPM-OOFDM-DSPM) is proposed and investigated, for the first time, for IMDD PON transmission systems. Compared to previously published similar transmission techniques, SIPM-OOFDM-DSPM not only enables more information bits to be conveyed in the extra information-carrying dimension but also improves the power usage efficiency, performance flexibility and adaptability without increasing DSP and hardware complexity. Detailed numerical simulations of the proposed technique are undertaken to identify optimum transceiver parameters, based on which its performance characteristics are explored. It is shown that over the aforementioned transmission systems, SIPM-OOFDM-DSPM considerably enhances the signal transmission capacity and simultaneously decreases the power penalty, in comparison with other subcarrier-index power-based OOFDM techniques encoded using similar signal modulation formats.