IQ imbalance compensation based on maximum SNR estimation in coherent QPSK systems

Author

Nguyen, T.-H. ; Gomez-Agis, Fausto ; Gay, M. ; Anet-Neto, Luiz ; Scalart, Pascal ; Peucheret, Christophe ; Joindot, Michel ; Sentieys, Olivier ; Simon, J.-C. ; Bramerie, L.

Author_Institution

Univ. Eur. de Bretagne (UEB), Rennes, France

fYear

2014

fDate

6-10 July 2014

Firstpage

1

Lastpage

4

Abstract

We present a simple alternative method for the compensation of quadrature imbalance in optical quadrature phase-shift-keying (QPSK) coherent systems. The method is based on the determination and the compensation of the phase mismatch by the introduction of a relevant signal-to-noise ratio metric. The principle is validated numerically and the algorithm is validated experimentally through bit-error-rate (BER) and error vector magnitude (EVM) measurements. A 20 Gb/s optical QPSK experiment reveals a good agreement of the proposed method with the Gram-Schmidt orthogonalization procedure (GSOP). Moreover, the robustness of both methods was verified with up to 30° phase misalignment by comparing the signal after phase imbalance compensation to that without compensation. A 10% reduction of EVM is achieved with our method for a high phase misalignment of 30°.

Keywords

error statistics; optical fibre communication; optical modulation; quadrature phase shift keying; EVM; Gram-Schmidt orthogonalization procedure; IQ imbalance compensation; bit rate 20 Gbit/s; bit-error-rate; coherent QPSK systems; error vector magnitude measurements; maximum SNR estimation; optical quadrature phase-shift-keying; phase mismatch; quadrature imbalance; robustness methods; signal-to-noise ratio metric; Bit error rate; Optical fibers; Optical receivers; Phase shift keying; Signal to noise ratio; coherent communications; digital signal processing; fiber optic communications; in-phase/quadrature imbalance;

fLanguage

English

Publisher

ieee

Conference_Titel

Transparent Optical Networks (ICTON), 2014 16th International Conference on

Conference_Location

Graz

Type

conf

DOI

10.1109/ICTON.2014.6876406

Filename

6876406