LDPC-coded modulation for beyond 100-Gb/s optical transmission

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


The future Internet traffic growth will require deployment of optical transmission systems with bit rates higher than rate of currently available 40-Gb/s systems, such as 100-Gb/s and above. However, at data rates beyond 100-Gb/s the signal quality is significantly degraded mainly due to impact of polarization mode dispersion (PMD), and intra-channel nonlinear effects. AU electrically time-division multiplexed (ETDM) multiplexers and de-multiplexers operating at ∼100-Gb/s are becoming commercially available. However, the modulators operating ∼100-Gb/s are not widely available so that alternative approaches to enable 100-Gb/s transmission and beyond using commercially available components operating at 40-Gb/s are of high practical importance. In this invited paper, several joint coded-modulation and multiplexing schemes enabling beyond 100-Gb/s transmission using commercially available components operating at 40-Gb/s are presented. Using this approach, modulation, coding and multiplexing are performed in a unified fashion so that, effectively, the transmission, signal processing, detection and decoding are done at much lower symbol rates, where dealing with the nonlinear effects and PMD is more manageable, while the aggregate data rate is maintained above 100-Gb/s. The main elements of our approach include: (i) bit-interleaved LDPC-coded modulation, (ii) multilevel coding (MLC) with LPDC component codes, and (iii) LDPC-coded orthogonal frequency division multiplexing (OFDM). The modulation formats of interest in this paper are M-ary quadrature-amplitude modulation (QAM) and M-ary phase-shift keying (PSK), where M=2,...,16, both combined with either Gray or natural mapping rule. It will be shown that coherent detection schemes significantly outperform direct detection ones and provide an additional margin that can be used either for longer transmission distances or for application in an all-optical networks.

Original languageEnglish (US)
Title of host publicationOptical Transmission Systems and Equipment for Networking VI
StatePublished - 2007
EventOptics East 2007 Conference on Optical Transmission Systems and Equipment for Networking VI - Boston, MA, United States
Duration: Sep 10 2007Sep 12 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOptics East 2007 Conference on Optical Transmission Systems and Equipment for Networking VI
Country/TerritoryUnited States
CityBoston, MA


  • Bit-interleaved coded modulation
  • Coherent detection
  • Direct detection
  • Low-density parity-check (ldpc) codes
  • Multilevel coding
  • Optical communications
  • Orthogonal frequency division multiplexing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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