An improved gaussian approximation for optically preamplified PPM systems including the effect of timing jitter

The effect of timing jitter is evaluated using an improved Gaussian approximation for an optically preamplified PPM receiver. For the parameters considered a potential sensitivity of 23.6 photons/bit is demonstrated in the unjittered case with the jittered optimum at worst only 1 dB less sensitive. Both these results surpass the fundamental sensitivity limit of an OOK NRZ system. The analysis predicts that wrong‐slot and jitter errors first become dominant at a coding level higher than that suggested by an earlier model. © 1995 John Wiley & Sons, Inc.