University of Hertfordshire

From the same journal

By the same authors


  • Sofien Mhatli
  • Marc F. C. Stephens
  • Athanasios Tsokanos
  • Jinlong Wei
  • Mary E. McCarthy
  • Nick J. Doran
  • Andrew D. Ellis
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Original languageEnglish
Pages (from-to) 2391-2397
Number of pages7
JournalJournal of Lightwave Technology
Early online date8 Mar 2017
Publication statusPublished - 15 Jun 2017


A fast Newton-based support vector machine (N-SVM) nonlinear equalizer (NLE) is experimentally demonstrated, for the first time, in 40 Gb/s 16-quadrature amplitude modulated coherent optical orthogonal frequency division multiplexing at 2000 km of transmission. It is shown that N-SVM-NLE extends the optimum launched optical power by 2 dB compared to the benchmark Volterra-based NLE. The performance improvement by N-SVM is due to its ability of tackling both deterministic fiber-induced nonlinear effects and the interaction between nonlinearities and stochastic noises (e.g. polarization-mode dispersion). N-SVM is more tolerant to inter-subcarrier nonlinear crosstalk effects than Volterra-based NLE, especially when applied across all subcarriers simultaneously. In contrast to the conventional SVM, the proposed algorithm is of reduced classifier complexity offering lower computational load and execution time. For a low C -parameter of 4 (a penalty parameter related to complexity), an execution time of 1.6 sec is required for N-SVM to effectively mitigate nonlinearities. Compared to conventional SVM, the computational load of N-SVM is ~6 times lower.


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