Digital Equalization of Chromatic Dispersion and Polarization Mode Dispersion

In this paper, we consider a fractionally spaced equalizer (FSE) for electronic compensation of chromatic dispersion (CD) and polarization-mode dispersion (PMD) in a dually polarized (polarization-multiplexed) coherent optical communications system. Our results show that the FSE can compensate any arbitrary amount of CD and first-order PMD distortion, provided that the oversampling rate is at least 3/2 and that a sufficient number of equalizer taps are used. In contrast, the amount of CD and PMD that can be corrected by a symbol-rate equalizer only approaches an asymptotic limit, and increasing the number of taps has no effect on performance due to aliasing that causes signal cancellation and noise enhancement.

[1]  G. Ungerboeck,et al.  Fractional Tap-Spacing Equalizer and Consequences for Clock Recovery in Data Modems , 1976, IEEE Trans. Commun..

[2]  R. D. Gitlin,et al.  Fractionally-spaced equalization: An improved digital transversal equalizer , 1981, The Bell System Technical Journal.

[3]  J. Salz,et al.  Linear equalization theory in digital data transmission over dually polarized fading radio channels , 1984, AT&T Bell Laboratories Technical Journal.

[4]  J.E. Mazo,et al.  Digital communications , 1985, Proceedings of the IEEE.

[5]  S. Qureshi,et al.  Adaptive equalization , 1982, Proceedings of the IEEE.

[6]  J. H. Winters,et al.  Equalization in coherent lightwave systems using a fractionally-spaced equalizer , 1990, [Proceedings] GLOBECOM '90: IEEE Global Telecommunications Conference and Exhibition.

[7]  J. G. Proakis.  Adaptive equalization for TDMA digital mobile radio , 1991 .

[8]  G. Agrawal.  Fiber‐Optic Communication Systems , 2021 .

[9]  John M. Cioffi,et al.  MMSE decision-feedback equalizers and coding. I. Equalization results , 1995, IEEE Trans. Commun..

[10]  K. Azadet,et al.  A low power 128-tap digital adaptive equalizer for broadband modems , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[11]  D. Schlump,et al.  Electronic equalisation of PMD and chromatic dispersion induced distortion after 100 km standard fibre at 10 Gbit/s , 1998, 24th European Conference on Optical Communication. ECOC '98 (IEEE Cat. No.98TH8398).

[12]  Reinhold Noe,et al.  Polarization mode dispersion compensation at 10, 20, and 40 Gb/s with various optical equalizers , 1999 .

[13]  H. Rosenfeldt,et al.  PMD compensation in 10 Gbit/s NRZ field experiment using polarimetric error signal , 2000 .

[14]  Keang-Po Ho,et al.  Spectrum of externally modulated optical signals , 2004, Journal of Lightwave Technology.

[15]  Keang-Po Ho,et al.  Generation of Arbitrary Quadrature-Amplitude Modulated Signals Using a Single Dual-Drive Modulator , 2004 .

[16]  M.G. Taylor,et al.  Coherent detection method using DSP for demodulation of signal and subsequent equalization of propagation impairments , 2004, IEEE Photonics Technology Letters.

[17]  J.M. Kahn,et al.  Performance of electrical equalizers in optically amplified OOK and DPSK systems , 2004, IEEE Photonics Technology Letters.

[18]  F. Buchali,et al.  Adaptive PMD compensation by electrical and optical techniques , 2004, Journal of Lightwave Technology.

[19]  Shanhui Fan,et al.  Principal modes in multimode waveguides. , 2005, Optics letters.

[20]  E. Ip,et al.  Power spectra of return-to-zero optical signals , 2006, Journal of Lightwave Technology.

[21]  K. Kikuchi,et al.  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 , 2006, IEEE Photonics Technology Letters.

[22]  K. Kikuchi,et al.  Coherent demodulation of optical multilevel phase-shift-keying signals using homodyne detection and digital signal processing , 2006, IEEE Photonics Technology Letters.