EXPERIMENTAL-STUDY OF THE STATISTICAL PROPERTIES OF NONLINEARLY AMPLIFIED SIGNALS IN SEMICONDUCTOR OPTICAL AMPLIFIERS

In this letter, we examine the effect of nonlinear amplification on th e noise properties of an amplified signal. We show that the output noi se statistics can be approximated as Gaussian over a wide range of pra ctical parameters. In addition, we show that nonlinear amplification o f noise carrying signals may result in an enhancement of the signal-to -noise ratio (SNR). Basic principles dictate that this can not improve the bit error rate performance of a communication link, as long as an optimal detection scheme is used. Hence, we conclude that for communi cation systems that exploit nonlinear amplification in semiconductor o ptical amplifiers, evaluation of performance on the basis of the SNR c an be misleading and should be made with great care.