Performance Prediction of Nonbinary Forward Error Correction in Optical Transmission Experiments

TL;DR

This paper demonstrates that mutual information is the best metric for predicting error rates in optical systems with nonbinary FEC, validated through simulations and experiments, emphasizing the need for universal FEC codes.

Contribution

It identifies mutual information as the optimal metric for performance prediction in nonbinary FEC optical systems and highlights the importance of universal FEC codes for accurate threshold-based predictions.

Findings

Mutual information accurately predicts error rates in optical systems with nonbinary FEC.

Universal FEC codes are necessary for reliable performance prediction.

Validation through simulations and optical transmission experiments.

Abstract

In this paper, we compare different metrics to predict the error rate of optical systems based on nonbinary forward error correction (FEC). It is shown that the correct metric to predict the performance of coded modulation based on nonbinary FEC is the mutual information. The accuracy of the prediction is verified in a detailed example with multiple constellation formats, FEC overheads in both simulations and optical transmission experiments over a recirculating loop. It is shown that the employed FEC codes must be universal if performance prediction based on thresholds is used. A tutorial introduction into the computation of the threshold from optical transmission measurements is also given.