Coded Pulse-Amplitude-Modulation for Intensity- Modulated Optical Communications

In this paper, we study the optimization of M-ary pulse-amplitude modulation (PAM) in the context of a coded modulation scheme for intensity-modulated optical communications. Building on previous approaches in literature, we propose to employ q-ary codes, in particular q-ary Polar codes, to achieve simplified mapping and a high degree of flexibility at low to moderate complexity. We focus on information-theoretic aspects and verify the performance of our coded modulation scheme using numerical simulations.