Abstract

With the recent advances of erbium-doped fiber amplifiers (EDFAs) the total unrepeatered distance for fiber-optic transmission near 1.55 pm has increased dramatically. In conventional (nondispersion- shifted) fiber systems the primary limitation is now dispersion, requiring sources with low chirp. For these systems, the simplicity of direct modulation of single-mode lasers is an attractive alternative to external modulation. We have used nine directly modulated distributed-Bragg reflector (DBR) lasers for 1.7-Gbit/s transmission through 257 km of conventional fiber with <2-dB dispersion penalty. This results in the best bit rate x distance product (437 km-Gbit/s) to date to our knowledge for directly modulated monolithic lasers between 1 and 3 Gbit/s through conventional single-mode fiber.

© 1992 Optical Society of America