Title :
On the Use of Delay-Decorrelated I/Q Test Sequences for QPSK and QAM Signals
Author :
Sierra, Alberto ; Randel, Sebastian ; Winzer, Peter J. ; Ryf, Roland ; Gnauck, Alan H. ; Essiambre, René-Jean
Author_Institution :
Bell Labs., Alcatel-Lucent, Holmdel, NJ, USA
fDate :
6/15/2012 12:00:00 AM
Abstract :
We report on limitations of the commonly used method to generate complex optical signal constellations from delay-decorrelated copies of a bit sequence to modulate in-phase (I) and quadrature (Q) components of a signal constellation. Using closed-form analytical solutions, numerical simulations, and an experimental verification, we show that I/Q delays shorter than the combined channel and adaptive equalizer length can result in artificial improvements of the measured bit-error ratio.
Keywords :
adaptive equalisers; delays; error statistics; optical fibre communication; optical modulation; optical testing; quadrature amplitude modulation; quadrature phase shift keying; I/Q delays; QAM signals; QPSK signals; adaptive equalizer length; bit sequence; bit-error ratio measurement; closed-form analytical solutions; combined channel length; complex optical signal constellations; delay-decorrelated I/Q test sequences; delay-decorrelated copies; experimental verification; modulate in-phase components; modulate quadrature components; numerical simulations; Adaptive equalizers; Bit error rate; Correlation; Crosstalk; Gain; Phase shift keying; Adaptive equalization; Wiener filter; spatial multiplexing;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2012.2192423
