Abstract

We report and experimentally investigate the performance of an adaptive decision-directed channel equalizer (ADDCE) in reduced-guard-interval dual-polarization coherent-optical orthogonal-frequency-division-multiplexing (RGI-DP-CO-OFDM) transport systems. ADDCE retrieves an estimation of the phase noise value after an initial decision making stage by extracting and averaging the phase drift of all OFDM sub-channels. Moreover, it updates the channel transfer matrix on a symbol-by-symbol basis. We experimentally compare the performance of the ADDCE and the conventional equalizer (CE) combined with maximum-likelihood (ML) phase noise compensation and inter-subcarrier-frequency-averaging (ISFA) algorithms. The study is conducted at 28 GBaud for RGI-DP-CO-OFDM systems with quadrature-phase-shift-keying (QPSK) and 16 quadrature amplitude modulation (16-QAM) formats. Using ADDCE, zero-overhead laser phase noise compensation is accomplished and the overhead due to training symbol (TSs) insertion is significantly reduced. In addition, ADDCE offers a superior performance over the CE in the presence of synchronization timing errors and residual chromatic dispersion (CD). We also achieve a longer transmission distance than when using the CE. At a forward-error-correction (FEC) threshold of 3.8 × 10−3, using a cumulative overhead of less than 2.6%, transmission distances of 5500 km and 400 km were achieved for the cases of QPSK and 16-QAM RGI-DP-CO-OFDM, respectively.

© 2012 OSA

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. Shieh, H. Bao, and Y. Tang, “Coherent optical OFDM: theory and design,” Opt. Express 16(2), 841–859 (2008).
    [CrossRef] [PubMed]
  2. W. Shieh, X. Yi, Y. Ma, and Q. Yang, “Coherent optical OFDM: has its time come?” J. Opt. Netw. 7(3), 234–255 (2008).
    [CrossRef]
  3. M. E. Mousa-Pasandi and D. V. Plant, “Data-aided adaptive weighted channel equalizer for coherent optical OFDM,” Opt. Express 18(4), 3919–3927 (2010).
    [CrossRef] [PubMed]
  4. F. Buchali, R. Dischler, and X. Liu, “Optical OFDM: A Promising High-Speed Optical Transport Technology,” Bell Labs Tech. J. 14(1), 125–148 (2009).
    [CrossRef]
  5. S. L. Jansen, I. Morita, T. C. W. Schenk, N. Takeda, and H. Tanaka, “Coherent optical 25.8-Gb/s OFDM transmission over 4160-km SSMF,” J. Lightwave Technol. 26(1), 6–15 (2008).
    [CrossRef]
  6. X. Yi, W. Shieh, and Y. Tang, “Phase estimation for coherent optical OFDM,” IEEE Photon. Technol. Lett. 19(12), 919–921 (2007).
    [CrossRef]
  7. S. L. Jansen, I. Morita, N. Takeda, and H. Tanaka, “20-Gb/s OFDM transmission over 4,160-km SSMF enabled by RF-Pilot tone phase noise compensation,” in Optical Fiber Communication Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2007), paper PDP15.
  8. M. E. Mousa-Pasandi and D. V. Plant, “Improvement of phase noise compensation for coherent optical OFDM via data-aided phase equalizer,” in Optical Fiber Communication Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2010), paper JThA10.
  9. M. E. Mousa-Pasandi and D. V. Plant, “Zero-overhead phase noise compensation via decision-directed phase equalizer for coherent optical OFDM,” Opt. Express 18(20), 20651–20660 (2010).
    [CrossRef] [PubMed]
  10. J. Ran, R. Grunheid, H. Rohling, E. Bolinth, and R. Kern, “Decision-directed channel estimation method for OFDM systems with high velocities,” in Proceedings of IEEE Vehicular Technology Conference, (Institute of Electrical and Electronics Engineers, New York, 2003), 2358–2361.
  11. M. Rim, “Optimally combining decision-directed and pilot-symbol-aided channel estimation,” Electron. Lett. 39(6), 558–560 (2003).
    [CrossRef]
  12. X. Liu and F. Buchali, “A novel channel estimation method for PDM-OFDM enabling improved tolerance to WDM nonlinearity,” in Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper OWW5.
  13. X. Liu and F. Buchali, “Intra-symbol frequency-domain averaging based channel estimation for coherent optical OFDM,” Opt. Express 16(26), 21944–21957 (2008).
    [CrossRef] [PubMed]
  14. C. J. Youn, X. Liu, S. Chandrasekhar, Y. H. Kwon, J. H. Kim, J. S. Choe, D. J. Kim, K. S. Choi, and E. S. Nam, “Channel estimation and synchronization for polarization-division multiplexed CO-OFDM using subcarrier/polarization interleaved training symbols,” Opt. Express 19(17), 16174–16181 (2011).
    [CrossRef] [PubMed]
  15. S. Chen, Q. Yang, Y. Ma, and W. Shieh, “Real-time multi-gigabit receiver for coherent optical MIMO-OFDM signals,” J. Lightwave Technol. 27(16), 3699–3704 (2009).
  16. X. Liu, S. Chandrasekhar, B. Zhu, P. J. Winzer, A. H. Gnauck, and D. W. Peckham, “448-Gb/s reduced-guard-interval CO-OFDM transmission over 2000 km of ultra-large-area fiber and five 80-GHz-grid ROADMs,” J. Lightwave Technol. 29(4), 483–490 (2011).
    [CrossRef]
  17. B. Spinnler, “Equalizer Design and Complexity for Digital Coherent Receivers,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1180–1192 (2010).
    [CrossRef]

2011 (2)

2010 (3)

2009 (2)

F. Buchali, R. Dischler, and X. Liu, “Optical OFDM: A Promising High-Speed Optical Transport Technology,” Bell Labs Tech. J. 14(1), 125–148 (2009).
[CrossRef]

S. Chen, Q. Yang, Y. Ma, and W. Shieh, “Real-time multi-gigabit receiver for coherent optical MIMO-OFDM signals,” J. Lightwave Technol. 27(16), 3699–3704 (2009).

2008 (4)

2007 (1)

X. Yi, W. Shieh, and Y. Tang, “Phase estimation for coherent optical OFDM,” IEEE Photon. Technol. Lett. 19(12), 919–921 (2007).
[CrossRef]

2003 (1)

M. Rim, “Optimally combining decision-directed and pilot-symbol-aided channel estimation,” Electron. Lett. 39(6), 558–560 (2003).
[CrossRef]

Bao, H.

Buchali, F.

F. Buchali, R. Dischler, and X. Liu, “Optical OFDM: A Promising High-Speed Optical Transport Technology,” Bell Labs Tech. J. 14(1), 125–148 (2009).
[CrossRef]

X. Liu and F. Buchali, “Intra-symbol frequency-domain averaging based channel estimation for coherent optical OFDM,” Opt. Express 16(26), 21944–21957 (2008).
[CrossRef] [PubMed]

Chandrasekhar, S.

Chen, S.

Choe, J. S.

Choi, K. S.

Dischler, R.

F. Buchali, R. Dischler, and X. Liu, “Optical OFDM: A Promising High-Speed Optical Transport Technology,” Bell Labs Tech. J. 14(1), 125–148 (2009).
[CrossRef]

Gnauck, A. H.

Jansen, S. L.

Kim, D. J.

Kim, J. H.

Kwon, Y. H.

Liu, X.

Ma, Y.

Morita, I.

Mousa-Pasandi, M. E.

Nam, E. S.

Peckham, D. W.

Plant, D. V.

Rim, M.

M. Rim, “Optimally combining decision-directed and pilot-symbol-aided channel estimation,” Electron. Lett. 39(6), 558–560 (2003).
[CrossRef]

Schenk, T. C. W.

Shieh, W.

Spinnler, B.

B. Spinnler, “Equalizer Design and Complexity for Digital Coherent Receivers,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1180–1192 (2010).
[CrossRef]

Takeda, N.

Tanaka, H.

Tang, Y.

W. Shieh, H. Bao, and Y. Tang, “Coherent optical OFDM: theory and design,” Opt. Express 16(2), 841–859 (2008).
[CrossRef] [PubMed]

X. Yi, W. Shieh, and Y. Tang, “Phase estimation for coherent optical OFDM,” IEEE Photon. Technol. Lett. 19(12), 919–921 (2007).
[CrossRef]

Winzer, P. J.

Yang, Q.

Yi, X.

W. Shieh, X. Yi, Y. Ma, and Q. Yang, “Coherent optical OFDM: has its time come?” J. Opt. Netw. 7(3), 234–255 (2008).
[CrossRef]

X. Yi, W. Shieh, and Y. Tang, “Phase estimation for coherent optical OFDM,” IEEE Photon. Technol. Lett. 19(12), 919–921 (2007).
[CrossRef]

Youn, C. J.

Zhu, B.

Bell Labs Tech. J. (1)

F. Buchali, R. Dischler, and X. Liu, “Optical OFDM: A Promising High-Speed Optical Transport Technology,” Bell Labs Tech. J. 14(1), 125–148 (2009).
[CrossRef]

Electron. Lett. (1)

M. Rim, “Optimally combining decision-directed and pilot-symbol-aided channel estimation,” Electron. Lett. 39(6), 558–560 (2003).
[CrossRef]

IEEE J. Sel. Top. Quantum Electron. (1)

B. Spinnler, “Equalizer Design and Complexity for Digital Coherent Receivers,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1180–1192 (2010).
[CrossRef]

IEEE Photon. Technol. Lett. (1)

X. Yi, W. Shieh, and Y. Tang, “Phase estimation for coherent optical OFDM,” IEEE Photon. Technol. Lett. 19(12), 919–921 (2007).
[CrossRef]

J. Lightwave Technol. (3)

J. Opt. Netw. (1)

Opt. Express (5)

Other (4)

X. Liu and F. Buchali, “A novel channel estimation method for PDM-OFDM enabling improved tolerance to WDM nonlinearity,” in Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper OWW5.

J. Ran, R. Grunheid, H. Rohling, E. Bolinth, and R. Kern, “Decision-directed channel estimation method for OFDM systems with high velocities,” in Proceedings of IEEE Vehicular Technology Conference, (Institute of Electrical and Electronics Engineers, New York, 2003), 2358–2361.

S. L. Jansen, I. Morita, N. Takeda, and H. Tanaka, “20-Gb/s OFDM transmission over 4,160-km SSMF enabled by RF-Pilot tone phase noise compensation,” in Optical Fiber Communication Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2007), paper PDP15.

M. E. Mousa-Pasandi and D. V. Plant, “Improvement of phase noise compensation for coherent optical OFDM via data-aided phase equalizer,” in Optical Fiber Communication Conference, OSA Technical Digest Series (CD) (Optical Society of America, 2010), paper JThA10.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (11)

Fig. 1
Fig. 1

RGI-DP-CO-OFDM experimental setup.

Fig. 2
Fig. 2

BER vs. OSNR for 28 GBaud QPSK RGI-DP-CO-OFDM at optical B2B.

Fig. 3
Fig. 3

BER vs. OSNR for 28 GBaud 16-QAM RGI-DP-CO-OFDM at optical B2B.

Fig. 4
Fig. 4

BER vs. launch power for 28 GBaud QPSK RGI-DP-CO-OFDM at 3280 km.

Fig. 5
Fig. 5

BER vs. launch power for 28 GBaud 16-QAM RGI-DP-CO-OFDM at 328 km.

Fig. 6
Fig. 6

BER vs. synchronization timing error for 28 GBaud QPSK RGI-DP-CO-OFDM at 3280 km.

Fig. 7
Fig. 7

BER vs. synchronization timing error for 28 GBaud 16-QAM RGI-DP-CO-OFDM at 328 km.

Fig. 8
Fig. 8

BER vs. residual dispersion for 28 GBaud QPSK RGI-DP-CO-OFDM at 3280 km.

Fig. 9
Fig. 9

BER vs. residual dispersion for 28 GBaud 16-QAM RGI-DP-CO-OFDM at 328 km.

Fig. 10
Fig. 10

BER vs. distance for 28 GBaud QPSK RGI-DP-CO-OFDM.

Fig. 11
Fig. 11

BER vs. distance for 28 GBaud 16-QAM RGI-DP-CO-OFDM.

Equations (18)

Equations on this page are rendered with MathJax. Learn more.

[ S ^ n,k X S ^ n,k Y ]= [ H ˜ n1,k XX H ˜ n1,k XY H ˜ n1,k YX H ˜ n1,k YY ] 1 ×[ R ^ n,k X R ^ n,k Y ]
S ¯ n,k =Decision S ^ n,k
Δ φ n = ( Δ φ n X +Δ φ n Y ) 2 = ( i=1 N ( arg{ R ^ n,i X }arg{ S ¯ n,i X } ) )+( i=1 N ( arg{ R ^ n,i Y }arg{ S ¯ n,i Y } ) ) 2×N
S n,k =Decision S ^ n,k × e jΔ φ n
H ^ n,k XY = H ˜ n1,k XY × e jΔ φ n ifmod(n,2)=0
H ^ n,k YX = H ˜ n1,k YX × e jΔ φ n ifmod(n,2)=0
H ^ n,k XX = R ^ n,k X H ˜ n,k XY × S n,k Y S n,k X ifmod(n,2)=0
H ^ n,k YY = R ^ n,k Y H ˜ n,k YX × S n,k X S n,k Y ifmod(n,2)=0
H ^ n,k XX = H ˜ n1,k XX × e jΔ φ n ifmod(n,2)=1
H ^ n,k YY = H ˜ n1,k YY × e jΔ φ n ifmod(n,2)=1
H ^ n,k XY = R ^ n,k X H ˜ n,k XX × S n,k X S n,k Y ifmod(n,2)=1
H ^ n,k YX = R ^ n,k Y H ˜ n,k YY × S n,k Y S n,k X ifmod(n,2)=1
H ˜ n,k XX =( 1γ )× H ˜ n1,k XY × e jΔ φ n +γ× H ^ n,k XX
H ˜ n,k YY =( 1γ )× H ˜ n1,k YY × e jΔ φ n +γ× H ^ n,k YY
H ˜ n,k XY =( 1γ )× H ˜ n1,k XY × e jΔ φ n +γ× H ^ n,k XY
H ˜ n,k YX =( 1γ )× H ˜ n1,k YX × e jΔ φ n +γ× H ^ n,k YX
C CE = N 1 ( log 2 ( N 1 )+1 ) n MC ( N 1 N CD +1 ) log 2 ( M ) + n MC log 2 ( N 2 )+2+ 5 N CE R CE log 2 ( M )
C ADDCE = N 1 ( log 2 ( N 1 )+1 ) n MC ( N 1 N CD +1 ) log 2 ( M ) + n MC log 2 ( N 2 )+2+ 5 N CE R CE log 2 ( M ) + 6 N 2 / n MC + 4 N 2 / n MC + 6 N 2 / n MC 2 N 2 log 2 ( M ) / n MC = C CE + 8 log 2 ( M )

Metrics