Title :
Compensation of Frequency Offset for Differentially Encoded 16- and 64-QAM in the Presence of Laser Phase Noise
Author :
Fatadin, Irshaad ; Ives, David ; Savory, Seb J.
Author_Institution :
Nat. Phys. Lab., Teddington, UK
Abstract :
The compensation of frequency offset for differentially encoded 16- and 64-ary quadrature amplitude modulation (QAM) in the presence of laser phase noise is investigated. Differential encoding is employed to solve the four-fold phase ambiguity problem in a nondata-aided transmission system with square QAM constellations. Simulation results show that frequency offset and phase noise can successfully be compensated using a second-order digital filter loop for the square QAM constellations.
Keywords :
digital filters; encoding; laser noise; optical fibre communication; optical modulation; phase noise; quadrature amplitude modulation; 16-QAM; 64-QAM; differential encoding; four-fold phase ambiguity problem; frequency offset compensation; laser phase noise; nondata-aided transmission system; quadrature amplitude modulation; second-order digital filter loop; square QAM; Differential encoding (DE); frequency offset; phase recovery; quadrature amplitude modulation (QAM);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2009.2037329
