Distortion penalty measurement technique in optical systems based on signal level adjustment

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 indicates the signal-to-noise ratio of the electric signal regenerated by the receiver. In the absence of distortion, Q is univocally determined by the BER. Q is calculated using an estimated BER measured with the path under normal conditions of operation, and a distortion-free Q is determined in the same operating point of the system. The distortion penalty for the path is obtained by comparing the measured Q with the distortion free Q. In addition, the distortion penalty for a transmittter-receiver pair, and a distortion penalty for a transmission link between the transmitter and receiver may be determined.