Alternative Decoding Methods for Optical Communications Based on Nonlinear Fourier Transform

Tao Gui, Terence H. Chan, Chao Lu, Alan Pak Tao Lau, Ping-Kong Alexander Wai

Research output: Contribution to journalJournal articlepeer-review

99 Citations (Scopus)

Abstract

Long-haul optical communications based on nonlinear Fourier Transform have gained attention recently as a new communication strategy that inherently embrace the nonlinear nature of the optical fiber. For communications using discrete eigenvalues λ ∈ ℂ+ , information are encoded and decoded in the spectral amplitudes q(λ) = b(λ)/(da(λ)/dλ) at the root λrt where a(λrt) = 0. In this paper, we propose two alternative decoding methods using a(λ) and b(λ) instead of q(λ) as decision metrics. For discrete eigenvalue modulation systems, we show that symbol decisions using a(λ) at a prescribed set of λ values perform similarly to conventional methods using q(λ) but avoid root searching, and, thus, significantly reduce computational complexity. For systems with phase and amplitude modulation on a given discrete eigenvalue, we propose to use b(λ) after for symbol detection and show that the noise in da(λ)/dλ and λrt after transmission is all correlated with that in b(λrt). A linear minimum mean square error estimator of the noise in b(λrt) is derived based on such noise correlation and transmission performance is considerably improved for QPSK and 16- quadratic-amplitude modulation systems on discrete eigenvalues.

Original languageEnglish
Pages (from-to)1542-1550
Number of pages9
JournalJournal of Lightwave Technology
Volume35
Issue number9
Early online date17 Jan 2017
DOIs
Publication statusPublished - May 2017

Scopus Subject Areas

  • Atomic and Molecular Physics, and Optics

User-Defined Keywords

  • Fiber nonlinearity
  • noise
  • nonlinear Fourier transform

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