Alreesh, S.S.AlreeshSchmidt-Langhorst, C.C.Schmidt-LanghorstFrey, F.F.FreyBerenguer, P.W.P.W.BerenguerSchubert, C.C.SchubertFischer, J.K.J.K.Fischer2022-03-042022-03-042015https://publica.fraunhofer.de/handle/publica/23961810.1109/LPT.2015.2391078The performance of the 4-D 128SP-QAM format is experimentally investigated in a Nyquist-wavelength division multiplexing system for two different forward error correction (FEC) scenarios. Two soft-decisions FEC schemes are experimentally evaluated for 128SP-QAM, namely, a turbo product code (TPC) and a low-density parity-check (LDPC) code. The results show that after full convergence the LDPC code outperforms the TPC with respect to coding gain at a bit error ratio of 10(-8). However, it requires more decoding iterations to achieve convergence toward an optimum performance state.en535journal article