279 km, 591 Mb/s direct detection transmission experiment using four in-line semiconductor optical amplifiers

Abstract

The authors realized a direct detection intensity-modulation system experiment with four cascaded in-line semiconductor optical amplifiers. Using optical isolators between the amplifiers, they transmitted a NRZ 2/sup 23/-1 message over a distance of 279 km at a bit rate of 591.2 Mb/s. A comparison of this result with parallel experiments without optical isolators indicates that for a realistic implementation of long distance systems with semiconductor optical amplifiers, interamplifier optical isolators will be needed unless the residual facet reflectivity of the optical amplifiers is brought to a very low value (<1*10/sup -4/).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>