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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 26 — Dec. 10, 2012
  • pp: B141–B150

Improved two-stage equalization for coherent Pol-Mux QPSK and 16-QAM systems

Chen Zhu, An V. Tran, Simin Chen, Liang B. Du, Trevor Anderson, Arthur J. Lowery, and Efstratios Skafidas  »View Author Affiliations

Optics Express, Vol. 20, Issue 26, pp. B141-B150 (2012)

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We report a two-stage blind frequency domain equalization method for long-haul coherent polarization-multiplexed (pol-mux) systems using quadrature phase shift keying (QPSK) and 16-quadrature amplitude modulation (16-QAM). In the first stage, blind CD parameter prediction is conducted prior to a CD equalizer. This supports flexible path switching in optical networks. In the second stage, a frequency-domain multi-modulus algorithm (MMA) equalizer is used to cope with the residual fiber impairments and perform polarization de-multiplexing. Compared with the conventional constant modulus algorithm (CMA), MMA shows advantages including better steady state performance and a faster convergence rate. Furthermore, all the estimation and equalization algorithms are implemented in the frequency domain which potentially provides the least complexity for the pol-mux optical coherent systems. The proposed algorithm is experimentally demonstrated with an 800-km 10 Gbaud coherent optical pol-mux system. For QPSK signal, the proposed method achieves error-free transmission and shows superior convergence speed against CMA, and for 16-QAM signals, the proposed MMA outperforms CMA with more than 1-dB improvement in Q-value.

© 2012 OSA

OCIS Codes
(060.1660) Fiber optics and optical communications : Coherent communications
(060.2330) Fiber optics and optical communications : Fiber optics communications
(060.4510) Fiber optics and optical communications : Optical communications

ToC Category:
Subsystems for Optical Networks

Original Manuscript: August 23, 2012
Manuscript Accepted: November 10, 2012
Published: November 28, 2012

Virtual Issues
European Conference on Optical Communication 2012 (2012) Optics Express

Chen Zhu, An V. Tran, Simin Chen, Liang B. Du, Trevor Anderson, Arthur J. Lowery, and Efstratios Skafidas, "Improved two-stage equalization for coherent Pol-Mux QPSK and 16-QAM systems," Opt. Express 20, B141-B150 (2012)

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  1. J. Yu and X. Zhou, “Ultra-high-capacity DWDM transmission system for 100G and beyond,” IEEE Commun. Mag.48(3), S56–S64 (2010). [CrossRef]
  2. P. J. Winzer, A. H. Gnauck, C. R. Doerr, M. Magarini, and L. L. Buhl, “Spectrally efficient long-haul optical networking using 112-Gb/s polarization-multiplexed 16-QAM,” J. Lightwave Technol.28(4), 547–556 (2010). [CrossRef]
  3. I. Fatadin, D. Ives, and S. J. Savory, “Blind equalization and carrier phase recovery in a 16-QAM coherent optical system,” J. Lightwave Technol.27(15), 3042–3049 (2009). [CrossRef]
  4. T. Pfau, S. Hoffmann, and R. Noé, “Hardware-efficient coherent digital receiver concept with feedforward carrier recovery for M-QAM constellations,” J. Lightwave Technol.27(8), 3042–3049 (2009). [CrossRef]
  5. S. J. Savory, “Digital filters for coherent optical receivers,” Opt. Express16(2), 804–817 (2008). [CrossRef] [PubMed]
  6. M. Kuschnerov, M. Chouayakh, K. Piyawanno, B. Spinnler, E. de Man, P. Kainzmaier, M. S. Alfiad, A. Napoli, and B. Lankl, “Data-aided versus blind single-carrier coherent receivers,” IEEE Photon. J.2(3), 387–403 (2010). [CrossRef]
  7. B. Spinnler, “Equalizer design and complexity for digital coherent receivers,” IEEE Sel. Top. in Quantum Electron.16(5), 1180–1192 (2010). [CrossRef]
  8. R. Kudo, T. Kobayashi, K. Ishihara, Y. Takatori, A. Sano, and Y. Miyamoto, “Coherent optical single carrier transmission using overlap frequency domain equalization for long-haul optical systems,” J. Lightwave Technol.27(16), 3721–3728 (2009). [CrossRef]
  9. A. V. Tran, C. Zhu, C. C. Do, S. Chen, T. Anderson, D. Hewitt, and E. Skafidas, “8×40-Gb/s optical coherent pol-mux single carrier system with frequency domain equalization and training sequences,” IEEE Photon. Technol. Lett.24(11), 885–887 (2012). [CrossRef]
  10. M. S. Faruk and K. Kikuchi, “Adaptive frequency-domain equalization in digital coherent optical receivers,” Opt. Express19(13), 12789–12798 (2011). [CrossRef] [PubMed]
  11. S. Yamanaka, T. Kobayashi, A. Sano, H. Masuda, E. Yoshida, Y. Miyamoto, T. Nakagawa, M. Nagatani, and H. Nosaka, “11 × 117 Gb/s PDM 16-QAM Transmission over 1440 km with a spectral efficiency of 6.4 b/s/Hz using high-speed DAC,” in European Conference and Exhibition on Optical Communication (ECOC), paper We.8.C.1 (2010).
  12. A. H. Gnauck, P. J. Winzer, C. R. Doerr, and L. L. Buhl, “10 × 112-Gb/s PDM 16-QAM transmission over 630 km of fiber with 6.2-b/s/Hz spectral efficiency,” in Optical Fiber Communication Conference (OFC), paper PDPB8 (2009).
  13. X. Zhou, J. Yu, M.-F. Huang, Y. Shao, T. Wang, P. Magill, M. Cvijetic, L. Nelson, M. Birk, G. Zhang, S. Ten, H. B. Matthew, and S. K. Mishra, “Transmission of 32-Tb/s capacity over 580 km using RZ-shaped PDM-8QAM modulation format and cascaded multimodulus blind equalization algorithm,” J. Lightwave Technol.28(4), 456–465 (2010). [CrossRef]
  14. C. Zhu, A. V. Tran, S. Chen, L. B. Du, T. Anderson, A. J. Lowery, and E. Skafidas, “Dual-stage frequency domain equalization for long-haul coherent polarization-multiplexed QPSK and 16-QAM systems,” in European Conference on Optical Communication (ECOC), paper We.1.A.2 (2012).
  15. T. Nakagawa, M. Matsui, T. Kobayashi, K. Ishihara, R. Kudo, M. Mizoguchi, and Y. Miyamoto, “Non-data-aided wide-range frequency offset estimator for QAM optical coherent receivers,” in Optical Fiber Communication Conference (OFC), paper OMJ1 (2011).
  16. S. Zhang, P. Y. Kam, C. Yu, and J. Chen, “Decision-aided carrier phase estimation for coherent optical communications,” J. Lightwave Technol.28(11), 1597–1607 (2010). [CrossRef]
  17. F. N. Hauske, Z. Zhang, C. Li, C. Xie, and Q. Xiong, “Precise, robust and least complexity CD estimation,” in Optical Fiber Communication Conference (OFC), paper JWA32 (2011).
  18. J. J. Shynk, “Frequency-domain and multirate adaptive filtering,” IEEE Sig. Proc. Mag.9(1), 14–37 (1992). [CrossRef]
  19. B. Porat, A Course in Digital Singal Processing (Wiley, 1997).
  20. J. Yang, J.-J. Werner, and G. A. Dumont, ““The multimodulus blind equalization and its generalized algorithms,” IEEE J. Sel. Areas on Commun.20(5), 997–1015 (2002). [CrossRef]

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