Open AccessDigital quadrature amplitude modulation with optimized non-rectangular constellations for 100 Gb/s transmission by a directly-modulated laser
Author(s) -
William A. Ling,
I. Lyubomirsky,
Olav Solgaard
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.010844
Subject(s) - quadrature amplitude modulation , optics , qam , modulation (music) , pulse amplitude modulation , constellation , amplitude modulation , transmission (telecommunications) , quadrature (astronomy) , constellation diagram , physics , laser , amplitude , phase shift keying , computer science , bit error rate , telecommunications , bandwidth (computing) , frequency modulation , acoustics , decoding methods , astronomy , detector , pulse (music)
We study the performance of novel quadrature amplitude modulation (QAM) constellations for 100 Gb/s transmission by a directly-modulated laser. Due to the strong nonlinearity of a directly-modulated laser, rectangular constellations suffer a large penalty from their regular spacing between symbols. We present a method for synthesizing irregular constellations which position symbols more efficiently. We will demonstrate the improved performance of these novel constellations over the conventional rectangular constellation as well as the superior performance achievable with digital QAM compared to optimally bit-loaded discrete-multitone modulation.