Title :
Recursive carrier phase tracking for synchronous multilevel 4QAM receivers
Author :
Cusani, R. ; Baccarelli, E. ; Salonico, A.
Author_Institution :
INFOCOM Dept., Rome Univ., Italy
fDate :
8/1/1995 12:00:00 AM
Abstract :
Four-quadrature amplitude modulation (4QAM) allows high spectral efficiency in coherent optical data transmission by exploiting the two phases and the two polarizations of the propagating wave. In this paper the performance of 4QAM is analyzed in the presence of laser phase noise and photodetection noise. A decision feedback phase tracking scheme based on the Kalman filter and leading to a novel hybrid PLL structure is employed and its accuracy evaluated. The computational complexity of the proposed phase estimator is also discussed. The performance of the resulting 4QAM system is evaluated in terms of bit error probability versus the signal-to-noise ratio Eb/N0, for different ratios of the symbol rate Rs over the laser linewidth BL
Keywords :
computational complexity; laser noise; optical feedback; optical fibre communication; optical fibre polarisation; optical modulation; optical receivers; phase locked loops; phase noise; photodetectors; probability; quadrature amplitude modulation; Kalman filter; bit error probability; coherent optical data transmission; computational complexity; decision feedback phase tracking scheme; four-quadrature amplitude modulation; high spectral; hybrid PLL structure; laser linewidth; laser phase noise; photodetection noise; propagating wave; recursive carrier phase tracking; signal-to-noise ratio; symbol rate; synchronous multilevel 4QAM receivers; Amplitude modulation; Data communication; Laser feedback; Optical feedback; Optical filters; Optical modulation; Optical noise; Optical polarization; Optical propagation; Phase noise;
Journal_Title :
Lightwave Technology, Journal of
