Abstract

We propose and demonstrate a novel multi-input multi-output (MIMO) equalization based inter-carrier-interference (ICI) cancellation approach employing constant modulus algorithm (CMA) for supperchanels with sub-Nyquist channel spacing, where optical combs are used as optical sources. Compared with the least mean square (LMS) algorithm based ICI canceller, the proposed approach has comparable capability to accomplish the ICI mitigation for 56 Gbaud dual-polarization quadrature phase shift keying (DP-QPSK) signals with tight channel spacing till 50 GHz. In particular, compared with the LMS-MIMO based ICI canceller, the optical linewidth tolerance of 6 MHz is relaxed to 20 MHz given a 1dB required optical signal-to-noise ratio (OSNR) penalty for the CMA-MIMO based ICI canceller. Meanwhile, the CMA-MIMO based ICI canceller is ideal for real-time processing, since the number of parallel processing pipelines can be greater than 240 even in the presence of large linewidth.

© 2013 OSA

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References

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  1. F. Buchali, K. Schuh, L. Schmalen, W. Idler, E. Lach, and A. Leven, “1-Tbit/s dual-carrier DP 64QAM transmission at 64Gbaud with 40% overhead soft-FEC over 320km SSMF,” in Proceedings of OFC (Anaheim, California, 2013), paper OTh4E.3.
    [CrossRef]
  2. G. Bosco, V. Curri, A. Carena, P. Poggiolini, and F. Forghieri, “On the Performance of Nyquist-WDM Terabit Superchannels Based on PM-BPSK, PM-QPSK, PM-8QAM or PM-16QAM Subcarriers,” J. Lightwave Technol.29(1), 53–61 (2011).
    [CrossRef]
  3. D. Qian, M. F. Huang, E. Ip, Y. K. Huang, Y. Shao, J. Hu, and T. Wang, “High capacity/spectral Efficiency 101.7-Tb/s WDM transmission using PDM-128QAM-OFDM over 165-km SSMF within C- and L-Bands,” J. Lightwave Technol.30(10), 1540–1548 (2012).
    [CrossRef]
  4. O. H. A. Jan, D. Sandel, K. Puntsri, A. Al-Bermani, M. El-Darawy, and R. Noé, “The robustness of subcarrier-index modulation in 16-QAM CO-OFDM system with 1024-point FFT,” Opt. Express20(27), 28963–28968 (2012).
    [CrossRef] [PubMed]
  5. X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. I. Borel, and K. Carlson, “PDM-Nyquist-32QAM for 450-Gb/s Per-Channel WDM Transmission on the 50 GHz ITU-T Grid,” J. Lightwave Technol.30(4), 553–559 (2012).
    [CrossRef]
  6. G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
    [CrossRef]
  7. J. Li, M. Karlsson, P. A. Andrekson, and K. Xu, “Transmission of 1.936 Tb/s (11 × 176 Gb/s) DP-16QAM superchannel signals over 640 km SSMF with EDFA only and 300 GHz WSS channel,” Opt. Express20(26), B223–B231 (2012).
    [CrossRef] [PubMed]
  8. J.-X. Cai, C. R. Davidson, A. Lucero, H. Zhang, D. G. Foursa, O. V. Sinkin, W. W. Patterson, A. N. Pilipetskii, G. Mohs, and N. S. Bergano, “20 Tbit/s transmission over 6860 km with sub-Nyquist channel spacing,” J. Lightwave Technol.30(4), 651–657 (2012).
    [CrossRef]
  9. Z. Jia, J. Yu, H. C. Chien, Z. Dong, and D. D. Huo, “Field Transmission of 100 G and Beyond: Multiple Baud Rates and Mixed Line Rates Using Nyquist-WDM Technology,” J. Lightwave Technol.30(24), 3793–3804 (2012).
    [CrossRef]
  10. J. Pan, C. Liu, T. F. Detwiler, A. J. Stark, Y. Hsueh, and S. E. Ralph, “Inter-channel crosstalk cancellation for Nyquist-WDM Superchannel applications,” J. Lightwave Technol.30(24), 3993–3999 (2012).
    [CrossRef]
  11. C. Liu, J. Pan, T. Detwiler, A. Stark, Y. T. Hsueh, G. K. Chang, and S. E. Ralph, “Joint digital signal processing for superchannel coherent optical communication systems,” Opt. Express21(7), 8342–8356 (2013).
    [CrossRef] [PubMed]
  12. C. Liu, J. Pan, T. Detwiler, A. Stark, Y. Hsueh, G. Chang, and S. E. Ralph, “Joint Digital Signal Processing for Superchannel Coherent Optical Systems: Joint CD Compensation for Joint ICI Cancellation,” in Proceedings of ECOC (Amsterdam, The Netherlands, 2012), paper Th.1.A.4.
    [CrossRef]
  13. C. Liu, J. Pan, T. Detwiler, A. Stark, Y. Hsueh, G. Chang, and S. E. Ralph, “Joint ICI Cancellation based on Adaptive Cross-Channel Linear Equalizer for Coherent Optical Superchannel Systems,” in Proceedings of Advanced Photonics Congress (Colorado Springs, Colorado, 2012), paper SpTu3A.2.
    [CrossRef]
  14. T. J. Pinkert, E. J. Salumbides, M. S. Tahvili, W. Ubachs, E. A. J. M. Bente, and K. S. E. Eikema, “Frequency comb generation by CW laser injection into a quantum-dot mode-locked laser,” Opt. Express20(19), 21357–21371 (2012).
    [CrossRef] [PubMed]
  15. Y. Ma, Q. Yang, Y. Tang, S. Chen, and W. Shieh, “1-Tb/s single-channel coherent optical OFDM transmission over 600-km SSMF fiber with subwavelength bandwidth access,” Opt. Express17(11), 9421–9427 (2009).
    [CrossRef] [PubMed]
  16. M. A. Foster, J. S. Levy, O. Kuzucu, K. Saha, M. Lipson, and A. L. Gaeta, “Silicon-based monolithic optical frequency comb source,” Opt. Express19(15), 14233–14239 (2011).
    [CrossRef] [PubMed]
  17. S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
    [CrossRef]
  18. L. B. Du, J. Schroeder, J. Carpenter, B. Eggleton, and A. J. Lowery, “Flexible All-Optical OFDM using WSSs,” in Proceedings of OFC (Anaheim, California, 2013), paper PDP5B.9.
  19. I. Fatadin, S. J. Savory, and D. Ives, “Compensation of quadrature imbalance in an optical QPSK coherent receiver,” IEEE Photon. Technol. Lett.20(20), 1733–1735 (2008).
    [CrossRef]
  20. M. Selmi, Y. Jaouen, and P. Ciblat, “Accurate digital frequency offset estimator for coherent PolMux QAM transmission systems,” in Proceedings of ECOC (Vienna, Austria, 2009),paper P3.08.
  21. A. J. Viterbi and A. M. Viterbi, “Nonlinear estimation of PSK-modulated carrier phase with application to burst digital transmission,” IEEE Trans. Inf. Theory29(4), 543–551 (1983).
    [CrossRef]
  22. J. Li and Z. Li, “Frequency-locked multicarrier generator based on a complementary frequency shifter with double recirculating frequency-shifting loops,” Opt. Lett.38(3), 359–361 (2013).
    [CrossRef] [PubMed]
  23. T. Zeng, “Superchannel transmission system based on multi-channel equalization,” Opt. Express21(12), 14799–14807 (2013).
    [CrossRef] [PubMed]

2013 (3)

2012 (8)

X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. I. Borel, and K. Carlson, “PDM-Nyquist-32QAM for 450-Gb/s Per-Channel WDM Transmission on the 50 GHz ITU-T Grid,” J. Lightwave Technol.30(4), 553–559 (2012).
[CrossRef]

J.-X. Cai, C. R. Davidson, A. Lucero, H. Zhang, D. G. Foursa, O. V. Sinkin, W. W. Patterson, A. N. Pilipetskii, G. Mohs, and N. S. Bergano, “20 Tbit/s transmission over 6860 km with sub-Nyquist channel spacing,” J. Lightwave Technol.30(4), 651–657 (2012).
[CrossRef]

D. Qian, M. F. Huang, E. Ip, Y. K. Huang, Y. Shao, J. Hu, and T. Wang, “High capacity/spectral Efficiency 101.7-Tb/s WDM transmission using PDM-128QAM-OFDM over 165-km SSMF within C- and L-Bands,” J. Lightwave Technol.30(10), 1540–1548 (2012).
[CrossRef]

T. J. Pinkert, E. J. Salumbides, M. S. Tahvili, W. Ubachs, E. A. J. M. Bente, and K. S. E. Eikema, “Frequency comb generation by CW laser injection into a quantum-dot mode-locked laser,” Opt. Express20(19), 21357–21371 (2012).
[CrossRef] [PubMed]

J. Li, M. Karlsson, P. A. Andrekson, and K. Xu, “Transmission of 1.936 Tb/s (11 × 176 Gb/s) DP-16QAM superchannel signals over 640 km SSMF with EDFA only and 300 GHz WSS channel,” Opt. Express20(26), B223–B231 (2012).
[CrossRef] [PubMed]

O. H. A. Jan, D. Sandel, K. Puntsri, A. Al-Bermani, M. El-Darawy, and R. Noé, “The robustness of subcarrier-index modulation in 16-QAM CO-OFDM system with 1024-point FFT,” Opt. Express20(27), 28963–28968 (2012).
[CrossRef] [PubMed]

Z. Jia, J. Yu, H. C. Chien, Z. Dong, and D. D. Huo, “Field Transmission of 100 G and Beyond: Multiple Baud Rates and Mixed Line Rates Using Nyquist-WDM Technology,” J. Lightwave Technol.30(24), 3793–3804 (2012).
[CrossRef]

J. Pan, C. Liu, T. F. Detwiler, A. J. Stark, Y. Hsueh, and S. E. Ralph, “Inter-channel crosstalk cancellation for Nyquist-WDM Superchannel applications,” J. Lightwave Technol.30(24), 3993–3999 (2012).
[CrossRef]

2011 (2)

2010 (1)

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

2009 (1)

2008 (1)

I. Fatadin, S. J. Savory, and D. Ives, “Compensation of quadrature imbalance in an optical QPSK coherent receiver,” IEEE Photon. Technol. Lett.20(20), 1733–1735 (2008).
[CrossRef]

1999 (1)

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

1983 (1)

A. J. Viterbi and A. M. Viterbi, “Nonlinear estimation of PSK-modulated carrier phase with application to burst digital transmission,” IEEE Trans. Inf. Theory29(4), 543–551 (1983).
[CrossRef]

Al-Bermani, A.

Andrekson, P. A.

Bennett, S.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

Bente, E. A. J. M.

Bergano, N. S.

Borel, P. I.

Bosco, G.

G. Bosco, V. Curri, A. Carena, P. Poggiolini, and F. Forghieri, “On the Performance of Nyquist-WDM Terabit Superchannels Based on PM-BPSK, PM-QPSK, PM-8QAM or PM-16QAM Subcarriers,” J. Lightwave Technol.29(1), 53–61 (2011).
[CrossRef]

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

Burr, E.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

Cai, B.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

Cai, J.-X.

Carena, A.

G. Bosco, V. Curri, A. Carena, P. Poggiolini, and F. Forghieri, “On the Performance of Nyquist-WDM Terabit Superchannels Based on PM-BPSK, PM-QPSK, PM-8QAM or PM-16QAM Subcarriers,” J. Lightwave Technol.29(1), 53–61 (2011).
[CrossRef]

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

Carlson, K.

Chang, G. K.

Chen, S.

Chien, H. C.

Curri, V.

G. Bosco, V. Curri, A. Carena, P. Poggiolini, and F. Forghieri, “On the Performance of Nyquist-WDM Terabit Superchannels Based on PM-BPSK, PM-QPSK, PM-8QAM or PM-16QAM Subcarriers,” J. Lightwave Technol.29(1), 53–61 (2011).
[CrossRef]

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

Davidson, C. R.

Detwiler, T.

Detwiler, T. F.

Dong, Z.

Eikema, K. S. E.

El-Darawy, M.

Fatadin, I.

I. Fatadin, S. J. Savory, and D. Ives, “Compensation of quadrature imbalance in an optical QPSK coherent receiver,” IEEE Photon. Technol. Lett.20(20), 1733–1735 (2008).
[CrossRef]

Forghieri, F.

G. Bosco, V. Curri, A. Carena, P. Poggiolini, and F. Forghieri, “On the Performance of Nyquist-WDM Terabit Superchannels Based on PM-BPSK, PM-QPSK, PM-8QAM or PM-16QAM Subcarriers,” J. Lightwave Technol.29(1), 53–61 (2011).
[CrossRef]

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

Foster, M. A.

Foursa, D. G.

Gaeta, A. L.

Gough, O.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

Hsueh, Y.

Hsueh, Y. T.

Hu, J.

Huang, M. F.

Huang, Y. K.

Huo, D. D.

Ip, E.

Isaac, R.

Ives, D.

I. Fatadin, S. J. Savory, and D. Ives, “Compensation of quadrature imbalance in an optical QPSK coherent receiver,” IEEE Photon. Technol. Lett.20(20), 1733–1735 (2008).
[CrossRef]

Jan, O. H. A.

Jia, Z.

Karlsson, M.

Kuzucu, O.

Levy, J. S.

Li, J.

Li, Z.

Lipson, M.

Liu, C.

Lucero, A.

Ma, Y.

Magill, P.

Mohs, G.

Nelson, L. E.

Noé, R.

Pan, J.

Patterson, W. W.

Peckham, D. W.

Pilipetskii, A. N.

Pinkert, T. J.

Poggiolini, P.

G. Bosco, V. Curri, A. Carena, P. Poggiolini, and F. Forghieri, “On the Performance of Nyquist-WDM Terabit Superchannels Based on PM-BPSK, PM-QPSK, PM-8QAM or PM-16QAM Subcarriers,” J. Lightwave Technol.29(1), 53–61 (2011).
[CrossRef]

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

Puntsri, K.

Qian, D.

Ralph, S. E.

Saha, K.

Salumbides, E. J.

Sandel, D.

Savory, S. J.

I. Fatadin, S. J. Savory, and D. Ives, “Compensation of quadrature imbalance in an optical QPSK coherent receiver,” IEEE Photon. Technol. Lett.20(20), 1733–1735 (2008).
[CrossRef]

Seeds, A. J.

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

Shao, Y.

Shieh, W.

Sinkin, O. V.

Stark, A.

Stark, A. J.

Tahvili, M. S.

Tang, Y.

Ubachs, W.

Viterbi, A. J.

A. J. Viterbi and A. M. Viterbi, “Nonlinear estimation of PSK-modulated carrier phase with application to burst digital transmission,” IEEE Trans. Inf. Theory29(4), 543–551 (1983).
[CrossRef]

Viterbi, A. M.

A. J. Viterbi and A. M. Viterbi, “Nonlinear estimation of PSK-modulated carrier phase with application to burst digital transmission,” IEEE Trans. Inf. Theory29(4), 543–551 (1983).
[CrossRef]

Wang, T.

Xu, K.

Yang, Q.

Yu, J.

Zeng, T.

Zhang, H.

Zhou, X.

Zhu, B.

IEEE Photon. Technol. Lett. (3)

G. Bosco, A. Carena, V. Curri, P. Poggiolini, and F. Forghieri, “Performance Limits of Nyquist-WDM and CO-OFDM in High-Speed PM-QPSK systems,” IEEE Photon. Technol. Lett.22(15), 1129–1131 (2010).
[CrossRef]

S. Bennett, B. Cai, E. Burr, O. Gough, and A. J. Seeds, “1.8-THz bandwidth, zero-frequency error, tunable optical comb generator for DWDM applications,” IEEE Photon. Technol. Lett.11(5), 551–553 (1999).
[CrossRef]

I. Fatadin, S. J. Savory, and D. Ives, “Compensation of quadrature imbalance in an optical QPSK coherent receiver,” IEEE Photon. Technol. Lett.20(20), 1733–1735 (2008).
[CrossRef]

IEEE Trans. Inf. Theory (1)

A. J. Viterbi and A. M. Viterbi, “Nonlinear estimation of PSK-modulated carrier phase with application to burst digital transmission,” IEEE Trans. Inf. Theory29(4), 543–551 (1983).
[CrossRef]

J. Lightwave Technol. (6)

Opt. Express (7)

M. A. Foster, J. S. Levy, O. Kuzucu, K. Saha, M. Lipson, and A. L. Gaeta, “Silicon-based monolithic optical frequency comb source,” Opt. Express19(15), 14233–14239 (2011).
[CrossRef] [PubMed]

T. J. Pinkert, E. J. Salumbides, M. S. Tahvili, W. Ubachs, E. A. J. M. Bente, and K. S. E. Eikema, “Frequency comb generation by CW laser injection into a quantum-dot mode-locked laser,” Opt. Express20(19), 21357–21371 (2012).
[CrossRef] [PubMed]

J. Li, M. Karlsson, P. A. Andrekson, and K. Xu, “Transmission of 1.936 Tb/s (11 × 176 Gb/s) DP-16QAM superchannel signals over 640 km SSMF with EDFA only and 300 GHz WSS channel,” Opt. Express20(26), B223–B231 (2012).
[CrossRef] [PubMed]

O. H. A. Jan, D. Sandel, K. Puntsri, A. Al-Bermani, M. El-Darawy, and R. Noé, “The robustness of subcarrier-index modulation in 16-QAM CO-OFDM system with 1024-point FFT,” Opt. Express20(27), 28963–28968 (2012).
[CrossRef] [PubMed]

Y. Ma, Q. Yang, Y. Tang, S. Chen, and W. Shieh, “1-Tb/s single-channel coherent optical OFDM transmission over 600-km SSMF fiber with subwavelength bandwidth access,” Opt. Express17(11), 9421–9427 (2009).
[CrossRef] [PubMed]

C. Liu, J. Pan, T. Detwiler, A. Stark, Y. T. Hsueh, G. K. Chang, and S. E. Ralph, “Joint digital signal processing for superchannel coherent optical communication systems,” Opt. Express21(7), 8342–8356 (2013).
[CrossRef] [PubMed]

T. Zeng, “Superchannel transmission system based on multi-channel equalization,” Opt. Express21(12), 14799–14807 (2013).
[CrossRef] [PubMed]

Opt. Lett. (1)

Other (5)

M. Selmi, Y. Jaouen, and P. Ciblat, “Accurate digital frequency offset estimator for coherent PolMux QAM transmission systems,” in Proceedings of ECOC (Vienna, Austria, 2009),paper P3.08.

L. B. Du, J. Schroeder, J. Carpenter, B. Eggleton, and A. J. Lowery, “Flexible All-Optical OFDM using WSSs,” in Proceedings of OFC (Anaheim, California, 2013), paper PDP5B.9.

C. Liu, J. Pan, T. Detwiler, A. Stark, Y. Hsueh, G. Chang, and S. E. Ralph, “Joint Digital Signal Processing for Superchannel Coherent Optical Systems: Joint CD Compensation for Joint ICI Cancellation,” in Proceedings of ECOC (Amsterdam, The Netherlands, 2012), paper Th.1.A.4.
[CrossRef]

C. Liu, J. Pan, T. Detwiler, A. Stark, Y. Hsueh, G. Chang, and S. E. Ralph, “Joint ICI Cancellation based on Adaptive Cross-Channel Linear Equalizer for Coherent Optical Superchannel Systems,” in Proceedings of Advanced Photonics Congress (Colorado Springs, Colorado, 2012), paper SpTu3A.2.
[CrossRef]

F. Buchali, K. Schuh, L. Schmalen, W. Idler, E. Lach, and A. Leven, “1-Tbit/s dual-carrier DP 64QAM transmission at 64Gbaud with 40% overhead soft-FEC over 320km SSMF,” in Proceedings of OFC (Anaheim, California, 2013), paper OTh4E.3.
[CrossRef]

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Figures (7)

Fig. 1
Fig. 1

(a) System configuration of WDM terabit superchannels. (b) Block diagram of 3-carrier joint DSP flow using LMS-MIMO based ICI cancellation. (c) Block diagram of 3-carrier joint DSP flow using CMA-MIMO based ICI cancellation. MUX/DMUX: wavelength multiplexer/ demultiplexer; Cho Rx: coherent receiver; ADC: Analog–to-digital conversion; IQ comp: in-phase/quadrature imbalance compensation; CMA Pol.Dmux: CMA based polarization demultiplexing; FR: frequency offset recovery; CR: carrier recovery.

Fig. 2
Fig. 2

(a) Required OSNR at BER = 10−3 as a function of optical filter bandwidth, channel spacing = 56 GHz; (b) Required OSNR at BER = 10−3 versus channel spacing, optical filter bandwidth = 62 GHz.

Fig. 3
Fig. 3

(a) Linewidth tolerance for Nyquist-spaced and sub-Nyquist-spaced superchannels; (b) Required OSNR as a function of the Viterbi-Viterbi block size for 50 GHz spacing and linewidth = 1 MHz .

Fig. 4
Fig. 4

The central tap coefficients magnitude versus iteration number for (a) LMS-MIMO based ICI canceller (Y-polarization) with viterbi-viterbi block size = 20; (b)LMS-MIMO based ICI canceller (Y-polarization) with viterbi-viterbi block size = 30; (c) LMS-MIMO based ICI canceller (Y-polarization) with viterbi-viterbi block size = 50; (d) CMA-MIMO based ICI canceller (Y- polarization);

Fig. 5
Fig. 5

Q factor as a function of parallel pipeline number for (a) linewidth = 100 kHz. (b) linewidth = 6 MHz

Fig. 6
Fig. 6

Required OSNR at BER = 10−3 with respect to fiber transmission distances at 12 dBm optical launch power for the 56 GHz channel spacing.

Fig. 7
Fig. 7

BER of CMA-MIMO and conventional DSP with respect to frequency offset, under the condition of OSNR = 20 dB and channel spacing of 50/56 GHz.

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