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IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 24, NO. 23, DECEMBER 1, 2012
Comments and Corrections Corrections to “Error Vector Magnitude as a Performance Measure for Advanced Modulation Formats”
Additionally, the paper should include the following Appendix.
Rene Schmogrow, Bernd Nebendahl, Marcus Winter, Arne Josten, David Hillerkuss, Swen Koenig, Joachim Meyer, Michael Dreschmann, Michael Huebner, Christian Koos, Juergen Becker, Wolfgang Freude, and Juerg Leuthold
The OSNR as used in our equations is the optical signal-to-noise power ratio measured in the same bandwidth BO and in the same polarization as the signal power. This is equivalent to the definition of the electrical SNR and differs from the usual measurement practice, where the optical signal-to-noise power ratio OSNRref is the total signal power (measured in both polarizations) and the total noise power from both polarizations measured in a reference bandwidth Bref . The reference bandwidth thereby is defined by a fixed wavelength range λref = Bref c/λ2ref = 0.1 nm (vacuum speed of light c) centered at a reference wavelength λref . The OSNR definition in our equation and the OSNRref definitions are related by 2Bref OSNRref (6) OSNR = p · BO
In the above paper [1], equation (4) contains an error. Equation (4) correctly reads: 1 − L −1 1 3 log2 L BER ≈ . (4) erfc log2 L L 2 − 1 (kEVMm )2 log2 M
Manuscript received September 11, 2012; accepted September 11, 2012. R. Schmogrow, A. Josten, D. Hillerkuss, S. Koenig, J. Meyer, M. Dreschmann, M. Huebner, C. Koos, J. Becker, W. Freude, and J. Leuthold are with the Karlsruhe Institute of Technology, Karlsruhe 76131, Germany (e-mail:
[email protected]; arne.josten@student. kit.edu;
[email protected];
[email protected]; joachim.meyer@ kit.edu;
[email protected];
[email protected]; christian.koos@kit. edu;
[email protected];
[email protected]; juerg.leuthold@ kit.edu). B. Nebendahl is with Agilent Technologies, Boeblingen 71034, Germany (e-mail:
[email protected]). M. Winter was with the Karlsruhe Institute of Technology, Karlsruhe 76131, Germany. He is now with Polytec (e-mail:
[email protected]). Digital Object Identifier 10.1109/LPT.2012.2219471
A PPENDIX
with p = 1 for a single polarization signal and p = 2 for a polarization multiplexed signal (see R.J. Essiambre et al; J. of Lightwave Technol., vol. 28, no. 4, pp. 662 ff., April 2011). If there are signal or noise correlations between the two transmitted polarizations, the applicability of our formulae has to be re-checked.
R EFERENCES [1] R. Schmogrow, et al., “Error vector magnitude as a performance measure for advanced modulation formats,” IEEE Photon. Technol. Lett., vol. 24, no. 1, pp. 61–63, Jan. 1, 2012.
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