Digital pulse position modulation over optical fibres with avalanche photodiode receivers

The question of performance evaluation in digital pulse position modulation (PPM) transmitted over slightly dispersive optical fibres and detected by avalanche photodiodes (APD) is considered. In view of numerical complexity implicit in exact average error probability evaluation, a bound on this probability is derived. Making use of this bound we conclude that optical fibre PPM receivers based on APDs offer some improvement over optical fibre PPM receivers based on PINFETs and a big improvement when compared with PCM receivers.