Power Domain Hybrid Modulation-Based Coherent Optical Transmission with Successive Interference Cancelation

The 6G era necessitates advanced multiplexing techniques that fully utilize various physical dimensions, including time, frequency, polarization, and space to enhance the achievable bitrate per wavelength and satisfy growing demands for capacity and spectral efficiency. Power domain hybrid modulation (PDHM) emerges as a viable technology to overcome the orthogonal limitations inherent in existing multiplexing schemes. In this paper, we introduce an iterative successive interference cancelation (SIC) algorithm for coherent optical transmission systems employing PDHM. The proposed system multiplexes a 16-ary quadrature amplitude modulation (16-QAM) signal with a quadrature phase shift keying (QPSK) signal at distinct power ratios. With the proposed iterative SIC, the system performance is improved by about one order of magnitude.