Abstract

With the undersea optical-amplifier systems in operation in 1995-1996, the next nonregenerated transoceanic links will increase the capacity by nearly an order of magnitude. This noticeable improvement comes from the technological breakthrough of the erbium-doped-fiber amplifiers (EDFA’s), which have a high pumping efficiency¹ with low-noise operation. Either by circulating-loop configurations² or by long straight links^3,4 in laboratory environments, several experiments were reported demonstrating the full capability of such undersea lightwave systems to transmit digital signals at 2.5 and 5 Gbit/s over at least 9000 km.

© 1993 Optical Society of America