Performance Analysis of Offset Pulse-Position Modulation Over an Optical Channel

This paper presents an original performance analysis of an offset pulse-position modulation (PPM) scheme using graded index plastic optical fiber with a Gaussian impulse response. The main aim of this analysis is to predict how sensitivity, error, number of required photons, threshold voltage, and the effect of intersymbol interference will change with the change in the number of data bits encoded at a rate of 1 Gbit/s. An information theory analysis is presented in detail and the bandwidth-utilization efficiency is determined. Results are compared to equivalent digital PPM and multiple PPM schemes and it is also shown that offset PPM gives a 7.5 dB advantage over nonreturn-to-zero on-off keying.