Influence of modulator chirp in assessing the performance implications of the group delay ripple of dispersion compensating fiber Bragg gratings

The implications that the group delay ripple (GDR) of a dispersion compensating fiber Bragg grating have on transmission system performance depend on the chirp of the modulated optical signal. The wide range in the chirp properties of optical modulators and the irregular variation of the GDR over the modulated signal bandwidth make it difficult to obtain general results for the transmission performance. Using four modulators with distinct chirp properties and measured reflection spectra for two dispersion compensating gratings (DCGs), the combined effect of modulator chirp and GDR on the performance of 10-Gb/s nonreturn-to-zero dispersion compensated systems is considered. Calculated and measured results demonstrate that, to accurately assess the implications of the GDR, the chirp properties of the modulated optical signal must be considered. The relative performance obtained for distinct modulators may vary significantly, depending on the details of the chirp and GDR.