We have demonstrated 2.5-Gb/s single-mode fiber-optic transmission usi
ng room temperature vertical-cavity surface-emitting lasers (VCSEL's)
operating at 1.54 mu m. The experiments were done over 60-km conventio
nal single-mode fiber and over 75-km dispersion shifted fiber without
optical amplification. Transmission over 200 km with one optical ampli
fier was also observed. Single-mode operation was demonstrated with a
side-mode suppression-ratio of 50 dB under pseudo-random modulation. T
he maximum bandwidth was limited hy parasitics to 4.7 GHz.