Subcarrier Index-Power Modulated Optical OFDM With Superposition Multiplexing for IMDD Transmission Systems

A novel signal transmission technique termed subcarrier index-power modulated optical OFDM with superposition multiplexing (SIPM-OOFDM-SPM) is proposed and investigated, for the first time, in which SIPM automatically creates an information-carrying subcarrier power pattern via assigning a high (low) signal modulation format to a high (low) power subcarrier, whilst SPM passively adds different signal modulation format-encoded complex numbers and assigns the sum to a high-power subcarrier. In comparison with conventional OOFDM, SIPM, and SPM enable extra information to be conveyed in both the new subcarrier index-power dimension and the conventional subcarrier-information-carrying dimension. In this paper, extensive numerical explorations of SIPM-OOFDM-SPM performance characteristics are undertaken, based on which optimum transceiver design parameters are identified. For IMDD PON systems, it is shown that SIPM-OOFDM-SPM considerably improves the signal transmission capacity, link power budget, and system performance tolerances to both chromatic dispersion and fiber nonlinearity.