Title :
Laser Linewidth Tolerance for 16-QAM Coherent Optical Systems Using QPSK Partitioning
Author :
Fatadin, Irshaad ; Ives, David ; Savory, Seb J.
Author_Institution :
Photonics Team, Nat. Phys. Lab., Teddington, UK
fDate :
5/1/2010 12:00:00 AM
Abstract :
The laser linewidth tolerance for 16-ary quadrature amplitude modulation (16-QAM) coherent optical systems is investigated using a quaternary phase-shift-keying (QPSK) partition scheme. The different stages needed to partition the square-16-QAM into QPSK constellations for carrier phase estimation are discussed. It is shown that at 1 dB above sensitivity at a bit-error rate of 10-3, a combined linewidths symbol duration product of 1 ?? 10-4 is tolerable. The performance of the algorithm with different bits resolution in the analog-to-digital converter is also presented.
Keywords :
analogue-digital conversion; error statistics; light coherence; optical communication equipment; optical modulation; phase estimation; quadrature amplitude modulation; quadrature phase shift keying; tolerance analysis; wavelength division multiplexing; 16-QAM coherent optical system; QPSK constellation; algorithm; analog-to-digital converter; bit-error rate; carrier phase estimation; laser linewidth tolerance; quadrature amplitude modulation; quaternary phase-shift-keying partitioning; square-16-QAM constellation; wavelength-division-multiplexing; Carrier phase recovery; quadrature amplitude modulation (QAM); quaternary phase-shift-keying (QPSK) partition;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2010.2043524
