Accuracy Assessment of Power Profile Estimation Using MMSE or Deconvoluted Profiles

We present an accuracy comparison between two longitudinal power profile estimation methods, the minimum mean square error (MMSE) method and the deconvolution of the correlation-based method. We first numerically evaluate the accuracy of each method and benchmark the deconvolution method versus the MMSE with respect to span input power, number of spans and modulation format. For both methods, we obtain a similar accuracy – root-mean square error (RMSE) of 0.14 dB at 5 dBm – at a given input power. We also show that using 16-QAM or 64-QAM for the modulation format instead of QPSK allows the deconvolution method to be more accurate and robust with the number of spans. Secondly, we perform a first experimental demonstration of the deconvolution method and assess the accuracy of both methods with commercial transponders in an optical networking testbed. We measure the RMSE of both – MMSE and deconvoluted – profiles with respect to the optical time-domain reflectometer (OTDR). We obtain close RMSE values as the average RMSE difference between both profiles is below 0.28 dB for the lightpath excluding the first span.