Abstract

We study a carrier-synchronization scheme for coherent optical communications that uses a feedforward architecture that can be implemented in digital hardware without a phase-locked loop. We derive the equations for maximum a posteriori joint detection of the transmitted symbols and the carrier phase. The result is a multidimensional optimization problem that we approximate with a two-stage iterative algorithm: The first stage is a symbol-by-symbol soft detector of the carrier phase, and the second stage is a hard-decision phase estimator that uses prior and subsequent soft-phase decisions to obtain a minimum mean-square-error phase estimate by exploiting the temporal correlation in the phase-noise process. The received symbols are then derotated by the hard-decision phase estimates, and maximum-likelihood sequence detection of the symbols follows. As each component in the carrier-recovery unit can be separately optimized, the resulting system is highly flexible. We show that the optimum hard-decision phase estimator is a linear filter whose impulse response consists of a causal and an anticausal exponential sequence, which we can truncate and implement as an finite-impulse-response filter. We derive equations for the phase-error variance and the system bit-error ratio (BER). Our results show that 4, 8, and 16 quadrature-amplitude-modulation (QAM) transmissions at 1 dB above sensitivity for BER=10-3 is possible with laser beat linewidths of ΔνTb=1.3×10-4, 1.3 x 10-4, and 1.5 x 10-5 when a decision-directed soft-decision phase estimator is employed.

© 2007 IEEE

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  1. J. R. Barry, J. M. Kahn, "Carrier synchronization for homodyne and heterodyne detection of optical quadriphase-shift keying ," J. Lightw. Technol. 10, 1939-1951 (1992).
  2. E. Ip, J. M. Kahn, "Carrier synchronization for 3- and 4-bit-per-symbol optical transmission," J. Lightw. Technol. 23, 4110-4124 (2005).
  3. E. Ip, J. M. Kahn, D. Anthon, J. Hutchins, "Linewidth measurements of MEMS-based tunable lasers for phase-locking applications," IEEE Photon. Technol. Lett. 17, 2029-2031 (2005).
  4. S. Tsukamoto, K. Katoh, K. Kikuchi, "Unrepeated transmission of 20-Gb/s optical quadrature phase-shift-keying signal over 200-km standard single-mode fiber based on digital processing of homodyne-detected signal for group-velocity dispersion compensation," IEEE Photon. Technol. Lett. 18, 1016-1018 (2006).
  5. S. Tsukamoto, K. Katoh, K. Kikuchi, "Coherent demodulation of optical multilevel phase-shift-keying signals using homodyne detection and digital signal processing," IEEE Photon. Technol. Lett. 18, 1131-1133 (2006).
  6. M. G. Taylor, "Coherent detection method using DSP for demodulation of signal and subsequent equalization of propagation impairments," IEEE Photon. Technol. Lett. 16, 674-676 (2004).
  7. M. Secondini, E. Forestieri, G. Prati, "PLC optical equalizer for chromatic and polarization-mode dispersion compensation based on MSE control," IEEE Photon. Technol. Lett. 16, 1173-1175 (2004).
  8. E. Ip, J. M. Kahn, "Digital equalization of chromatic dispersion and polarization mode dispersion," J. Lightw. Technol. 25, 2033-2043 (2007).
  9. M. G. Taylor, "Accurate digital phase estimation process for coherent detection using a parallel digital processor," Proc. ECOC (2005) pp. 263-264.
  10. D.-S. Ly-Gagnon, S. Tsukamoto, K. Katoh, K. Kikuchi, "Coherent detection of optical quadrature phase-shift keying signals with carrier phase estimation ," J. Lightw. Technol. 24, 12-21 (2006).
  11. K. Kikuchi, "Coherent detection of phase-shift keying signals using digital carrier-phase estimation ," Proc. Opt. Fiber Commun. Conf. (2006).
  12. H. Xu, Q. Huang, H. Zheng, "On the blind carrier phase estimation for large QAM constellation," Proc. 17th Int. Conf. AINA (2003) pp. 551-554.
  13. L. Chen, H. Kusaka, "Blind phase recovery in QAM communication systems using higher order statistics," IEEE Signal Process. Lett. 3, 147-149 (1996).
  14. C. Georghiades, "Blind carrier phase acquisition for QAM constellations," IEEE Trans. Commun. 45, 1477-1486 (1997).
  15. M. G. Taylor, "Measurement of phase diagrams of optical communication signals using sampled coherent detection ," Proc. Symp. Opt. Fiber Meas. Tech. Dig. (2004) pp. 163-166.
  16. R. Noe, "Phase noise-tolerant synchronous QPSK/BPSK baseband-type intradyne receiver concept with feedforward carrier recovery," J. Lightw. Technol. 23, 802-808 (2005).
  17. H. Meyr, M. Moeneclaey, S. Fechtel, Digital Communication Receivers (Wiley, 1997).
  18. V. K. Prabhu, "PSK performance with imperfect carrier phase recovery," IEEE Trans. Aerosp. Electron. Syst. AES-12, 275-285 (1976).
  19. I. S. Gradshteyn, I. M. Ryzhik, A. Jeffrey, Table of Integrals, Series and Products (Academic, 1994).
  20. D.-S. Ly-Gagnon, Information recovery using coherent detection and digital signal processing for phase-shift-keying modulation formats in optical communication systems M.S. thesis Univ. TokyoTokyoJapan (2004).

2007 (1)

E. Ip, J. M. Kahn, "Digital equalization of chromatic dispersion and polarization mode dispersion," J. Lightw. Technol. 25, 2033-2043 (2007).

2006 (3)

D.-S. Ly-Gagnon, S. Tsukamoto, K. Katoh, K. Kikuchi, "Coherent detection of optical quadrature phase-shift keying signals with carrier phase estimation ," J. Lightw. Technol. 24, 12-21 (2006).

S. Tsukamoto, K. Katoh, K. Kikuchi, "Unrepeated transmission of 20-Gb/s optical quadrature phase-shift-keying signal over 200-km standard single-mode fiber based on digital processing of homodyne-detected signal for group-velocity dispersion compensation," IEEE Photon. Technol. Lett. 18, 1016-1018 (2006).

S. Tsukamoto, K. Katoh, K. Kikuchi, "Coherent demodulation of optical multilevel phase-shift-keying signals using homodyne detection and digital signal processing," IEEE Photon. Technol. Lett. 18, 1131-1133 (2006).

2005 (3)

E. Ip, J. M. Kahn, "Carrier synchronization for 3- and 4-bit-per-symbol optical transmission," J. Lightw. Technol. 23, 4110-4124 (2005).

E. Ip, J. M. Kahn, D. Anthon, J. Hutchins, "Linewidth measurements of MEMS-based tunable lasers for phase-locking applications," IEEE Photon. Technol. Lett. 17, 2029-2031 (2005).

R. Noe, "Phase noise-tolerant synchronous QPSK/BPSK baseband-type intradyne receiver concept with feedforward carrier recovery," J. Lightw. Technol. 23, 802-808 (2005).

2004 (2)

M. G. Taylor, "Coherent detection method using DSP for demodulation of signal and subsequent equalization of propagation impairments," IEEE Photon. Technol. Lett. 16, 674-676 (2004).

M. Secondini, E. Forestieri, G. Prati, "PLC optical equalizer for chromatic and polarization-mode dispersion compensation based on MSE control," IEEE Photon. Technol. Lett. 16, 1173-1175 (2004).

1997 (1)

C. Georghiades, "Blind carrier phase acquisition for QAM constellations," IEEE Trans. Commun. 45, 1477-1486 (1997).

1996 (1)

L. Chen, H. Kusaka, "Blind phase recovery in QAM communication systems using higher order statistics," IEEE Signal Process. Lett. 3, 147-149 (1996).

1992 (1)

J. R. Barry, J. M. Kahn, "Carrier synchronization for homodyne and heterodyne detection of optical quadriphase-shift keying ," J. Lightw. Technol. 10, 1939-1951 (1992).

1976 (1)

V. K. Prabhu, "PSK performance with imperfect carrier phase recovery," IEEE Trans. Aerosp. Electron. Syst. AES-12, 275-285 (1976).

IEEE Photon. Technol. Lett. (5)

E. Ip, J. M. Kahn, D. Anthon, J. Hutchins, "Linewidth measurements of MEMS-based tunable lasers for phase-locking applications," IEEE Photon. Technol. Lett. 17, 2029-2031 (2005).

S. Tsukamoto, K. Katoh, K. Kikuchi, "Unrepeated transmission of 20-Gb/s optical quadrature phase-shift-keying signal over 200-km standard single-mode fiber based on digital processing of homodyne-detected signal for group-velocity dispersion compensation," IEEE Photon. Technol. Lett. 18, 1016-1018 (2006).

S. Tsukamoto, K. Katoh, K. Kikuchi, "Coherent demodulation of optical multilevel phase-shift-keying signals using homodyne detection and digital signal processing," IEEE Photon. Technol. Lett. 18, 1131-1133 (2006).

M. G. Taylor, "Coherent detection method using DSP for demodulation of signal and subsequent equalization of propagation impairments," IEEE Photon. Technol. Lett. 16, 674-676 (2004).

M. Secondini, E. Forestieri, G. Prati, "PLC optical equalizer for chromatic and polarization-mode dispersion compensation based on MSE control," IEEE Photon. Technol. Lett. 16, 1173-1175 (2004).

IEEE Signal Process. Lett. (1)

L. Chen, H. Kusaka, "Blind phase recovery in QAM communication systems using higher order statistics," IEEE Signal Process. Lett. 3, 147-149 (1996).

IEEE Trans. Aerosp. Electron. Syst. (1)

V. K. Prabhu, "PSK performance with imperfect carrier phase recovery," IEEE Trans. Aerosp. Electron. Syst. AES-12, 275-285 (1976).

IEEE Trans. Commun. (1)

C. Georghiades, "Blind carrier phase acquisition for QAM constellations," IEEE Trans. Commun. 45, 1477-1486 (1997).

J. Lightw. Technol. (5)

R. Noe, "Phase noise-tolerant synchronous QPSK/BPSK baseband-type intradyne receiver concept with feedforward carrier recovery," J. Lightw. Technol. 23, 802-808 (2005).

E. Ip, J. M. Kahn, "Digital equalization of chromatic dispersion and polarization mode dispersion," J. Lightw. Technol. 25, 2033-2043 (2007).

J. R. Barry, J. M. Kahn, "Carrier synchronization for homodyne and heterodyne detection of optical quadriphase-shift keying ," J. Lightw. Technol. 10, 1939-1951 (1992).

E. Ip, J. M. Kahn, "Carrier synchronization for 3- and 4-bit-per-symbol optical transmission," J. Lightw. Technol. 23, 4110-4124 (2005).

D.-S. Ly-Gagnon, S. Tsukamoto, K. Katoh, K. Kikuchi, "Coherent detection of optical quadrature phase-shift keying signals with carrier phase estimation ," J. Lightw. Technol. 24, 12-21 (2006).

Other (7)

K. Kikuchi, "Coherent detection of phase-shift keying signals using digital carrier-phase estimation ," Proc. Opt. Fiber Commun. Conf. (2006).

H. Xu, Q. Huang, H. Zheng, "On the blind carrier phase estimation for large QAM constellation," Proc. 17th Int. Conf. AINA (2003) pp. 551-554.

M. G. Taylor, "Accurate digital phase estimation process for coherent detection using a parallel digital processor," Proc. ECOC (2005) pp. 263-264.

H. Meyr, M. Moeneclaey, S. Fechtel, Digital Communication Receivers (Wiley, 1997).

M. G. Taylor, "Measurement of phase diagrams of optical communication signals using sampled coherent detection ," Proc. Symp. Opt. Fiber Meas. Tech. Dig. (2004) pp. 163-166.

I. S. Gradshteyn, I. M. Ryzhik, A. Jeffrey, Table of Integrals, Series and Products (Academic, 1994).

D.-S. Ly-Gagnon, Information recovery using coherent detection and digital signal processing for phase-shift-keying modulation formats in optical communication systems M.S. thesis Univ. TokyoTokyoJapan (2004).

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