Comparison of different feedback signals used in one stage PMD compensators for different modulation formats

• Published in: IEEE transactions on communications Vol. 56; no. 10; pp. 1722 - 1728
• Main Authors: Ducournau, Guillaume, Latry, Olivier, Joubert, Eric, Ketata, Mohamed
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bit error rate; Coding, codes; Compensation; Compensators; Correlation; Dopants; Exact sciences and technology; Feedback; Format; High speed optical techniques; Indicators; Information, signal and communications theory; Laboratories; Machinery; Modulation; Modulation coding; Modulation, demodulation; Optical communications; Optical feedback; Optical fiber communications; Optical modulation; Optical signal processing; Optical telecommunications; Optical variables control; Polarization mode dispersion; polarization mode dispersion (PMD); Signal and communications theory; System performance; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Performance evaluation; Feedback system; Optical telecommunication; Information rate; Duobinary transmission; Polarization mode dispersion; Information transmission; Optical communications; Modulation; Compensator; Optical fiber communication; Optical dispersion compensation; Modulation coding; Group delay; High rate transmission; polarization mode dispersion (PMD)
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2008.060476

As PMD compensation has become a very intense subject of research in recent years, the achievement of simple PMD compensators based on a feedback signal is a key issue. As PMD compensation uses a feedback indicator for system performance evaluation, such feedback signals must reproduce the DGD variations with time. In this paper, the correlation between DGD and different feedback signals is studied with a new method. This method is applied for various modulation schemes, leading to well-known results. By applying the method to the electrical and optical duobinary formats, it is shown that for duobinary signals, the DOP feedback signal shows the best correlation with instantaneous DGD value. Such a behavior of duobinary format is very interesting since duobinary modulation schemes are now considered for systems upgrades or mixed architectures (10 Gbit/s-40 Gbit/s on the same link). In such systems, PMD compensation has to be bit-rate independent which is available with the DOP as feedback indicator.