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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 15 — Jul. 18, 2011
  • pp: 14617–14631

Offset-QAM based coherent WDM for spectral efficiency enhancement

J. Zhao and A. D. Ellis  »View Author Affiliations

Optics Express, Vol. 19, Issue 15, pp. 14617-14631 (2011)

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Optically multiplexed multi-carrier systems with channel spacing reduced to the symbol rate per carrier are highly susceptible to inter-channel crosstalk, which places stringent requirements for the specifications of system components and hinders the use of high-level formats. In this paper, we investigate the performance benefits of using offset 4-, 16-, and 64-quadrature amplitude modulation (QAM) in coherent wavelength division multiplexing (CoWDM). We compare this system with recently reported Nyquist WDM and no-guard-interval optical coherent orthogonal frequency division multiplexing, and show that the presented system greatly relaxes the requirements for device specifications and enhances the spectral efficiency by enabling the use of high-level QAM. The achieved performance can approach the theoretical limits using practical components.

© 2011 OSA

OCIS Codes
(060.2330) Fiber optics and optical communications : Fiber optics communications
(060.4080) Fiber optics and optical communications : Modulation

ToC Category:
Fiber Optics and Optical Communications

Original Manuscript: May 25, 2011
Revised Manuscript: July 7, 2011
Manuscript Accepted: July 8, 2011
Published: July 14, 2011

J. Zhao and A. D. Ellis, "Offset-QAM based coherent WDM for spectral efficiency enhancement," Opt. Express 19, 14617-14631 (2011)

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