Abstract

Significant advances have been made in the application of directly modulated 1550-nm distributed feedback (DFB) lasers in long-span multi-Gbit/s transmission experiments using conventional single-mode fiber with minimum dispersion at 1300 nm.¹ These experiments in general employ state-of-the- art DFB lasers operating at carefully adjusted bias conditions with a substantial extinction ratio penalty for bit rates in excess of 2 Gbit/s. The performance of commonly available DFB lasers, however, could be dispersion-limited at much shorter distances: bit-error-rate floors were recently reported for distances of only 4 km at 2.4 Gbit/s (Ref. 2) and 30 km at 1.8 Gbit/s,³ the latter having a high side mode suppression ratio (SMSR) of 35 dB.

© 1988 Optical Society of America