BIT ERROR EVALUATION OF OPTICALLY PREAMPLIFIED DIRECT-DETECTION RECEIVERS WITH FABRY-PEROT OPTICAL FILTERS

The error performance of a preamplified. direct detection receiver wit h an optical filter of the Lorentzian type is studied, The analysis ta kes into account the influence of the optical intersymbol interference (ISI), A closed-form expression of the moment generating function (MG F) of the decision variable is derived, Error probabilities are evalua ted from the MGF using a saddlepoint approximation, The Gaussian appro ximation is also examined, The detection sensitivity in terms of a qua ntum limit is calculated. The results show that there exists an optimu m optical bandwidth, the reason being a tradeoff between the effect of ISI and the spontaneous emission noise. It is also shown that the Gau ssian approximation gives a good estimate of the error probability, al lowing to find in a simple manner the optimum parameters of optically preamplified, direct detection receiver.