Throughput efficiency considerations for optical OPPM

The authors derive a closed-form expression for the cutoff rate of optical overlapping pulse-position modulation (OPPM) systems valid for both the noiseless and the background noise cases and use it to study throughput efficiency for a fixed pulsewidth and data rate. Comparisons are made to pulse-position modulation, which was previously similarly studied, and to on-off keying (OOK). It is seen that OPPM is uniformly superior to PPM when pulsewidth and throughput constraints are imposed, especially for large required nats/slot when PPM fails, and it is superior to OOK over a large range of rates in nats/slot