Group-delay characterization of cascaded chirped fiber Bragg-grating dispersion compensators

Based on linear-system theory, a method to obtain the total group-delay characteristics of the cascaded chirped fiber Bragg grating (FBG) front the measured group delays of each grating is proposed. The method is then used to characterize cascaded chirped FBGs used as the dispersion compensators of an experimental eight-channel 10-Gb/s NRZ system over 1500-km G.652 fiber. The inband total local-dispersion deviation curve is calculated and shows good consistence with the tendency of the inband BER fluctuations, which indicates that the inband local dispersion deviation may be the main reason for the dependence of such a system performance on signal wavelength, and its RMS value can be taken as the indicator of performance tolerance to wavelength instability. Numerical simulation is also performed, by which a near linear scaling of the simulated EOP with total local-dispersion deviation is shown. (c) 2005 Wiley Periodicals, Inc.