Pointing Error Analysis of Optically Pre-Amplified Pulse Position Modulation Receivers

We present analytical results on the effect of pointing errors on the average bit-error probability (ABEP) of optically pre-amplified pulse-position modulation (PPM) receivers. The results show that the beam width plays a key role in the ABEP and that a significant power penalty is introduced by utilizing sub-optimal widths, especially when pointing errors incorporate a jitter component. We also present the optimisation the beam width for a number of pointing error scenarios and show that increasing beam widths are required as additional signal energy becomes available. The optimal beam width is also affected by the PPM modulation order and the optical noise modes, with more energy efficient (higher modulation order and lower noise) systems allowing for broader beams.