In this paper we present procedures for the extraction of laser rate equation parameters. The parameters are extracted using fitting of static and dynamic measurements with simple theoretical expressions. In particular, chirp related parameters are extracted directly through measured chirp and power waveforms. The extracted parameters are used in a large-signal rate equation laser model to calculate the power and chirp waveforms. The simulations are compared with experiments and the agreement is excellent. The procedures have been applied to directly modulated lasers having different chirp characteristics and designed for either 2.5 or 10 Gb/s operation. Using the rate equation laser model with the extracted parameters, we performed a simulation study to identify the value of employing a negative dispersion fiber in metro-area networks. It is shown that dispersion shifted fibers with negative dispersion across the entire usable fiber bandwidth (1280–1620 nm) advances the performance of directly modulated lasers used in wavelength division multiplexed metropolitan-area transmission systems and networks. At 2.5 Gb/s transmission over 300 km of negative dispersion fibers is possible for directly modulated lasers across the erbium doped fiber amplifier bandwidth, while at 10 Gb/s an impressive distance of 100 km can be achieved.