In this paper, the use of Single and Dual Drive Mach-Zehnder external modulators as Chromatic Dispersion compensators in a 10 Gbps optical network at a simulation level in RSoft's Optsim™ tool, by negative pre-chirping technique is studied. To verify the validity of the study, a behavior analysis of the Bit Error Rate, the eye diagram and the duration of the optical pulses in a comparative way was carried out. The obtained results presented improvement in the system through the chirp management of the modulators. Key words: Chromatic dispersion, Mach-Zehnder modulator, negative pre-chirping, chirp, Optsim.