Title :
Viterbi equalizer with analytically calculated branch metrics for optical ASK and DBPSK
Author :
Freckmann, Torsten ; Speidel, Joachim
Author_Institution :
Inst. of Telecommun., Univ. of Stuttgart, Germany
Abstract :
We analytically derive probability density functions of the sampled electrically filtered photo current for optical amplitude-shift keying and differential binary phase-shift keying using the Karhunen-Loe`ve series expansion method. This allows us to determine exact branch metrics for a Viterbi equalizer. We then compare the performance of histogram-based Viterbi equalizers with those using analytically calculated branch metrics.
Keywords :
Karhunen-Loeve transforms; amplitude shift keying; differential phase shift keying; equalisers; maximum likelihood estimation; optical communication equipment; probability; Karhunen-Loeve series expansion; Viterbi equalizer; amplitude-shift keying; branch metrics; differential binary phase-shift keying; electrically filtered photocurrent; histogram-based Viterbi equalizers; optical ASK; optical DBPSK; probability density functions; Amplitude shift keying; Equalizers; Fiber nonlinear optics; Maximum likelihood estimation; Nonlinear optics; Optical filters; Optical interferometry; Optical noise; Probability density function; Viterbi algorithm; Maximum likelihood sequence estimation (MLSE); Viterbi equalizer (VE); probability density function (pdf);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2005.860054
