Open AccessNear-ML detection for MDL-impaired few-mode fiber transmission
Author(s) -
Adriana Lobato,
Johannes Rabe,
Filipe Ferreira,
Maxim Kuschnerov,
Bernhard Spinnler,
Berthold Lankl
Publication year - 2015
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.009589
Subject(s) - computational complexity theory , algorithm , computer science , transmission (telecommunications) , minimum mean square error , phase shift keying , decoding methods , quadrature amplitude modulation , mode (computer interface) , optics , constellation , minimum description length , bit error rate , mathematics , physics , estimator , telecommunications , statistics , astronomy , operating system
Few-mode fiber transmission systems are typically impaired by mode-dependent loss (MDL). In an MDL-impaired link, maximum-likelihood (ML) detection yields a significant advantage in system performance compared to linear equalizers, such as zero-forcing and minimum-mean square error equalizers. However, the computational effort of the ML detection increases exponentially with the number of modes and the cardinality of the constellation. We present two methods that allow for near-ML performance without being afflicted with the enormous computational complexity of ML detection: improved reduced-search ML detection and sphere decoding. Both algorithms are tested regarding their performance and computational complexity in simulations of three and six spatial modes with QPSK and 16QAM constellations.