We have studied the performance of In, -.cGa,As,P, -buried heterostructure (BH) 1.3-pm lasers in the microwave range. This study consisted of small-signal, large-signal, and digital pseudo-random word evaluation of these lasers. The small-signal study pointed out the impact of the oxide stripe capacitance on the laser response at microwave frequencies. The large-signal study uncovered basic'laser nonlinearities that affect the temporal response, spectral broadening, and wavelength chirp. Finally, digital pseudo-random word tests performed at 1.7 Gbit/s indicated that in spite of these inherent laser nonlinearities, the 1.3-pm BH lasers performed well enough to be considered as promising sources for gigabit optical communication systems.