Abstract

Current research efforts in the fields of optical transmission are aimed at identifying how optical processing may be beneficial in the implementation of large scale networks. A prerequisite for such developments is the attainment of the largest possible unrepeatered span of individual links in the network. In this paper, we show how the maximum unrepeatered span of a 20-Gbit/s system (4 × 5-Gbit/s optical time-division multiplexed) may be enhanced by using a length of transmission fiber which has been lightly (50 ppb) doped with erbium ions to provide distributed preamplification at the receiver. The optical pump power for the distributed amplifier is provided from the terminal end only, resulting in true repeaterless operation.

© 1992 Optical Society of America