Abstract

We report the successful transmission of ten 494.85 Gbit/s DWDM signals on the standard 50 GHz ITU-T grid over 32 × 100 km of ultra-large-area (ULA) fiber. A net spectral efficiency (SE) of 8.25 b/s/Hz was achieved, after excluding the 20% soft-decision forward-error-correction (FEC) overhead. Such a result was accomplished by the use of a recently proposed polarization-division-μltiplexed (PDM) time-domain hybrid 32–64 quadrature-amplitude-modulation (QAM) format, along with improved carrier frequency and phase recovery algorithms. It is shown that time-domain hybrid QAM provides a new degree of design freedom to optimize the transmission performance by fine tuning the SE of the modulation format for a specific channel bandwidth and FEC redundancy requirement. In terms of carrier recovery, we demonstrate that 1) hardware efficient estimation and tracking of the frequency offset between the signal and local-oscillator (LO) can be achieved by using a new feedback-based method, and 2) a training-assisted two-stage phase estimation algorithm effectively mitigates cyclic phase slipping problems. This new phase recovery algorithm not only improves the receiver sensitivity by eliminating the need for differential coding and decoding, but also enables an additional equalization stage following the phase recovery. We have shown that the introduction of this additional equalization stage (with larger number of taps) helps reduce the implementation penalty. This paper also presents the first experimental study of the impact of inphase (I) and quadrature (Q) correlation for a high-order QAM. It is shown that an adaptive equalizer could exploit the correlation between I and Q signal components to artificially boost the performance by up to 0.7 dB for a PDM time-domain hybrid 32–64 QAM signal when the equalizer length is significantly longer than I/Q de-correlation delay.

© 2013 IEEE

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  2. J. Yu, X. Zhou, M. Huang, D. Qian, P. N. Ji, T. Wang, P. D. Magill, "400 Gb/s (4 × 100 Gb/s) orthogonal PDM-RZ-QPSK DWDM Signal Transmission over 1040 km SMF-28," Optics Express 17, 17928-17933 (2009).
  3. Y.-K. Huang, E. Ip, M.-F. Huang, B. Zhu, P. N. Ji, Y. Shao, D. W. Peckham, R. Lingle, JrY. Aono, T. Tajima, T. Wang, "10 × 456-Gb/s DP-16 QAM transmission over 8 × 100 km of ULAF using coherent detection with a 30-GHz analog-to-digital converter," OECC 2010 Japan (2010) paper PDP3.
  4. P. J. Winzer, A. H. Gnauck, S. Chandrasekhar, S. Draving, J. Evangelista, B. Zhu, "Generation and 1, 200-km transmission of 448-Gb/s ETDM 56-Gbaud PDM 16-QAM using a single I/Q modulator," ECOC 2010 TorinoItaly (2010) PDP 2.2.
  5. T. Kobayashi, A. Sano, A. Matsuura, Y. Miyamoto, K. Ishihara, "Nonlinear tolerant long-haul WDM transmission over 1200 km using 538 Gb/s/ch PDM-64 QAM SC-FDM signals with pilot tone," OFC-NFOEC 2012 Los AngelesCA (2012) paper OM2A.5.
  6. H. Takahashi, K. Takeshima, I. Morita, H. Tanaka, "400-Gbit/s optical OFDM transmission over 80 km in 50-GHz frequency grid," ECOC 2010 TorinoItaly (2010) paper Tu.3.C.1.
  7. X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. Borel, K. Carlson, "8 × 450-Gb/s, 50-GHz-spaced, PDM-32 QAM transmission over 400 km and one 50 GHz-grid ROADM," OFC-NFOEC 2011 Los AngelesCA (2011) paper PDPB3.
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  10. X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. Borel, K. Carlson, "4000 km transmission of 50 GHz spaced, 10 × 494.85 Gb/s hybrid- 32-64 QAM using cascaded equalization and training-assisted phase recovery," OFC-NFOEC 2012 Los AngelesCA (2012) paper PDP5C.6.
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  16. Y. Cao, S. Yu, J. Shen, W. Gu, Y. Ji, "Frequency estimation for optical coherent MPSK without removing modulated data phase," IEEE Photonics Technol. Lett. 22, 691-693 (2010).
  17. M. Selmi, Y. Jaouen, P. Ciblat, "Accurate, digital frequency offset estimator for coherent Polμx QAM transmission systems," ECOC 2009 ViennaAustria (2009) paper P 3.08.
  18. X. Zhou, "Hardware efficient carrier recovery algorithms for single-carrier QAM systems," OSA 2012 topical meeting, signal processing in photonic comμnication (SPPCom) Colorado SpringsUSA (2012) paper SpTu3A.1.
  19. S. Dris, I. Lazarou, P. Bakopoulos, H. Avramopoulos, "Phase entropy-based frequency offset estimation for coherent optical QAM systems," OFC-NFOEC 2012 Los AngelesCA (2012) paper PDP5C.6.
  20. X. Zhou, "An improved feed-forward carrier recovery algorithm for coherent receiver with M-QAM modulation format," IEEE Photonics Technol. Lett. 22, 1051-1053 (2010).
  21. T. Pfau, S. Hoffmann, R. Noé, "Hardware-efficient coherent digital receiver concept with feed-forward carrier recovery for M-QAM constellations," J. Lightwave. Technol. 27, 989-999 (2009).
  22. M. Dentino, J. M. McCool, B. Widrow, "Adaptive filtering in the frequency domain," Proc. IEEE 66, 1658-1659 (1978).
  23. D. Chang1, F. Yu, Z. Xiao, N. Stojanovic, F. N. Hauske, Y. Cai, C. Xie, L. Li, X. Xu, Q. Xiong, "LDPC convolutional codes using layered decoding algorithm for high speed coherent optical transmission," OFC-NFOEC 2012 Los AngelesCA (2012) paper OW1H.4.
  24. A. Sierra, S. Randel, P. J. Winzer, R. Ryf, A. H. Gnauck, R. Essiambre, On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals 24, 1000-1002 (2012).

2012 (2)

R. Schmogrow, M. Winter, M. Meyer, D. Hillerkuss, A. Ludwig, B. Nebendahl, S. Ben-Ezra, J. Meyer, M. Dreschmann, M. Huebner, J. Becker, C. Koos, W. Freude, J. Leuthold, "Real-time Nyquist pulse generation beyond 100 Gbit/s and its relation to OFDM," Optics Express 20, 317-337 (2012).

A. Sierra, S. Randel, P. J. Winzer, R. Ryf, A. H. Gnauck, R. Essiambre, On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals 24, 1000-1002 (2012).

2011 (1)

2010 (2)

Y. Cao, S. Yu, J. Shen, W. Gu, Y. Ji, "Frequency estimation for optical coherent MPSK without removing modulated data phase," IEEE Photonics Technol. Lett. 22, 691-693 (2010).

X. Zhou, "An improved feed-forward carrier recovery algorithm for coherent receiver with M-QAM modulation format," IEEE Photonics Technol. Lett. 22, 1051-1053 (2010).

2009 (2)

T. Pfau, S. Hoffmann, R. Noé, "Hardware-efficient coherent digital receiver concept with feed-forward carrier recovery for M-QAM constellations," J. Lightwave. Technol. 27, 989-999 (2009).

J. Yu, X. Zhou, M. Huang, D. Qian, P. N. Ji, T. Wang, P. D. Magill, "400 Gb/s (4 × 100 Gb/s) orthogonal PDM-RZ-QPSK DWDM Signal Transmission over 1040 km SMF-28," Optics Express 17, 17928-17933 (2009).

2007 (1)

A. Leven, "Frequency estimation in intradyne reception," IEEE Photon. Technol. Lett. 19, (2007).

1978 (1)

M. Dentino, J. M. McCool, B. Widrow, "Adaptive filtering in the frequency domain," Proc. IEEE 66, 1658-1659 (1978).

IEEE Photon. Technol. Lett. (1)

A. Leven, "Frequency estimation in intradyne reception," IEEE Photon. Technol. Lett. 19, (2007).

IEEE Photonics Technol. Lett. (2)

Y. Cao, S. Yu, J. Shen, W. Gu, Y. Ji, "Frequency estimation for optical coherent MPSK without removing modulated data phase," IEEE Photonics Technol. Lett. 22, 691-693 (2010).

X. Zhou, "An improved feed-forward carrier recovery algorithm for coherent receiver with M-QAM modulation format," IEEE Photonics Technol. Lett. 22, 1051-1053 (2010).

J. Lightwave Technol. (1)

J. Lightwave. Technol. (1)

T. Pfau, S. Hoffmann, R. Noé, "Hardware-efficient coherent digital receiver concept with feed-forward carrier recovery for M-QAM constellations," J. Lightwave. Technol. 27, 989-999 (2009).

On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals (1)

A. Sierra, S. Randel, P. J. Winzer, R. Ryf, A. H. Gnauck, R. Essiambre, On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals 24, 1000-1002 (2012).

Optics Express (2)

R. Schmogrow, M. Winter, M. Meyer, D. Hillerkuss, A. Ludwig, B. Nebendahl, S. Ben-Ezra, J. Meyer, M. Dreschmann, M. Huebner, J. Becker, C. Koos, W. Freude, J. Leuthold, "Real-time Nyquist pulse generation beyond 100 Gbit/s and its relation to OFDM," Optics Express 20, 317-337 (2012).

J. Yu, X. Zhou, M. Huang, D. Qian, P. N. Ji, T. Wang, P. D. Magill, "400 Gb/s (4 × 100 Gb/s) orthogonal PDM-RZ-QPSK DWDM Signal Transmission over 1040 km SMF-28," Optics Express 17, 17928-17933 (2009).

Proc. IEEE (1)

M. Dentino, J. M. McCool, B. Widrow, "Adaptive filtering in the frequency domain," Proc. IEEE 66, 1658-1659 (1978).

Other (15)

D. Chang1, F. Yu, Z. Xiao, N. Stojanovic, F. N. Hauske, Y. Cai, C. Xie, L. Li, X. Xu, Q. Xiong, "LDPC convolutional codes using layered decoding algorithm for high speed coherent optical transmission," OFC-NFOEC 2012 Los AngelesCA (2012) paper OW1H.4.

M. Selmi, Y. Jaouen, P. Ciblat, "Accurate, digital frequency offset estimator for coherent Polμx QAM transmission systems," ECOC 2009 ViennaAustria (2009) paper P 3.08.

X. Zhou, "Hardware efficient carrier recovery algorithms for single-carrier QAM systems," OSA 2012 topical meeting, signal processing in photonic comμnication (SPPCom) Colorado SpringsUSA (2012) paper SpTu3A.1.

S. Dris, I. Lazarou, P. Bakopoulos, H. Avramopoulos, "Phase entropy-based frequency offset estimation for coherent optical QAM systems," OFC-NFOEC 2012 Los AngelesCA (2012) paper PDP5C.6.

Y.-K. Huang, E. Ip, M.-F. Huang, B. Zhu, P. N. Ji, Y. Shao, D. W. Peckham, R. Lingle, JrY. Aono, T. Tajima, T. Wang, "10 × 456-Gb/s DP-16 QAM transmission over 8 × 100 km of ULAF using coherent detection with a 30-GHz analog-to-digital converter," OECC 2010 Japan (2010) paper PDP3.

P. J. Winzer, A. H. Gnauck, S. Chandrasekhar, S. Draving, J. Evangelista, B. Zhu, "Generation and 1, 200-km transmission of 448-Gb/s ETDM 56-Gbaud PDM 16-QAM using a single I/Q modulator," ECOC 2010 TorinoItaly (2010) PDP 2.2.

T. Kobayashi, A. Sano, A. Matsuura, Y. Miyamoto, K. Ishihara, "Nonlinear tolerant long-haul WDM transmission over 1200 km using 538 Gb/s/ch PDM-64 QAM SC-FDM signals with pilot tone," OFC-NFOEC 2012 Los AngelesCA (2012) paper OM2A.5.

H. Takahashi, K. Takeshima, I. Morita, H. Tanaka, "400-Gbit/s optical OFDM transmission over 80 km in 50-GHz frequency grid," ECOC 2010 TorinoItaly (2010) paper Tu.3.C.1.

X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. Borel, K. Carlson, "8 × 450-Gb/s, 50-GHz-spaced, PDM-32 QAM transmission over 400 km and one 50 GHz-grid ROADM," OFC-NFOEC 2011 Los AngelesCA (2011) paper PDPB3.

X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. Borel, K. Carlson, "800 km transmission of 5 × 450-Gb/s PDM-32 QAM on the 50 GHz grid using electrical and optical spectral shaping," ECOC 2011 GenevaSwitzerland (2011) paper We.8.B.2.

X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. Borel, K. Carlson, "1200 km transmission of 50 GHz spaced, 5 × 504-Gb/s PDM-32-64 hybrid QAM using electrical and optical spectral shaping," OFC-NFOEC 2012 Los AngelesCA (2012) paper OM2A.2.

X. Zhou, L. E. Nelson, P. Magill, R. Isaac, B. Zhu, D. W. Peckham, P. Borel, K. Carlson, "4000 km transmission of 50 GHz spaced, 10 × 494.85 Gb/s hybrid- 32-64 QAM using cascaded equalization and training-assisted phase recovery," OFC-NFOEC 2012 Los AngelesCA (2012) paper PDP5C.6.

W. R. Peng, I. Morita, H. Tanaka, "Hybrid QAM transmission techniques for single-carrier ultra-dense WDM systems," OECC 2011 KaohsiungTaiwan (2011) paper 8D2-4.

H. Takahashi, I. Morita, H. Tanaka, "The impact of the combined 8-QAM and QPSK subcarrier modulation for coherent optical OFDM," OFC-NFOEC 2011 Los AngelesCA (2011) paper JWA30.

X. Liu, S. Chandrasekhar, B. Zhu, A. H. Gnauck, D. W. Peckham, "Transmission of a 448-Gb/s reduced-guard-interval CO-OFDM signal with a 60-GHz optical bandwidth over 2000 km of ULAF and five 80-GHz-Grid ROADMs," Proc. OFC-NFOEC 2010 San DiegoCA (2010) paper PDPC2.

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