摘要 |
The BER is used as a parameter for evaluating the performance of an optical transmission system. Performance of optical systems is also defined by the Q factor, which uniquely determines the BER in the absence of distortion. The measurements are effected in a point of operation of the channel which gives a value of interest for the Q factor. To this end, the optical SNR is lowered by adding noise over the information signal. A distortion-free Q (Q DF) and a back-to-back Q (Q BB) are determined in the same operating point of the system. The distortion penalty for transmitter-receiver pair may be determined by comparing Q DF to Q BB The noise loading technique will allow to investigate if equalizing. The value of OSNRs at the output of a particular system results in equalizing the noise margin in that systems or not.
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