Heterodyne detection of multipulse signaling in optical communication channels

Abstract

Pulse position modulation (PPM) schemes are usually used in optical communication systems to improve the receiver sensitivity. Multi-PPM (MPPM) signaling has been presented as a very powerful alternative to the PPM format, for laser direct detection systems. Considering a similar information efficiency, it achieved a significant performance improvement at higher transmission rates, lesser bandwidth expansion, as well as better peak-to-average power ratios, with respect to the PPM model. We investigate extending the MPPM signaling to coherent optical communication systems. A performance analysis for the heterodyne detection of Steiner's multipulse model is analysed. Optimum code rates are determined for the signaling alphabets, and the pulse width is also optimized.