Title :
Ultralong lightwave systems with incomplete dispersion compensations
Author :
Wen, Senfar ; Lin, Tsung-Kun
Author_Institution :
Dept. of Electr. Eng., Chung Hua Univ., Hsinchu, Taiwan
fDate :
4/1/2001 12:00:00 AM
Abstract :
Ultralong nonreturn-to-zero optical transmission systems with incomplete dispersion compensations are studied. The dispersion of transmission fiber is periodically under- or overcompensated. Postdispersion compensation (PDC) at the receiver is used to compensate for the residual dispersion caused by incomplete compensation and to tailor the signal pulse shape. Formulas estimating the change of pulse width in the absence of amplifier noise during signal transmission and after PDC are given. During signal transmission, pulse width may be compressed or broadened by the combined effect of the dispersion and self-phase modulation (SPM). The change of pulse width nearly increases with the square of the distance during signal transmission. With amplifier noise, system performance evaluated by Q factor is studied. Several types of transmission fibers are considered. The Q factor can be significantly improved by proper PDC. Signal pulse is compressed when PDC is optimized. The characteristics of the maximum Q factor and the residual dispersion are studied, in which PDC is optimized. The results show that to achieve the best system performance, fiber dispersion should be undercompensated for positive dispersion parameter and overcompensated for negative dispersion parameter. The optimal fiber dispersion lies in the range from 4 to 10 ps/km/nm for the considered systems, and the optimal ratio of residual dispersion and fiber dispersion is about 1%
Keywords :
Q-factor; compensation; optical fibre communication; optical fibre dispersion; optimisation; self-phase modulation; Q factor; amplifier noise; dispersion parameter; incomplete dispersion compensation; maximum Q factor; negative dispersion parameter; optimal fiber dispersion; postdispersion compensation; receiver; residual dispersio; residual dispersion; self-phase modulation; signal pulse shape; signal transmission; system performance; ultralong lightwave systems; ultralong nonreturn-to-zero optical transmission systems; Fiber nonlinear optics; Optical amplifiers; Optical pulse shaping; Optical receivers; Pulse amplifiers; Pulse compression methods; Pulse width modulation; Q factor; Space vector pulse width modulation; System performance;
Journal_Title :
Lightwave Technology, Journal of
