Abstract

The use of fiber amplifiers in future lightwave systems now appears certain. Many experiments have been published demonstrating both the long-distance and multi-channel capability of fiber amplifier-based systems. Most experiments have used conventional direct detection systems [1,2]; but some experiments, including a record transmission distance experiment, have used coherent detection systems [3,4]; and models of both systems have been developed. This paper will compare the two systems under the same conditions using both experiments and models. We will emphasize a practical comparison by using a direct detection regenerator from AT&T’s commercial, 1.7 Gb/s system and a shelf-mounted, coherent detection regenerator from a recent AT&T field trial [5]. We will also emphasize a direct comparison by using transmitters of the same wavelength and identical optical paths including erbium-doped fiber amplifiers.

© 1991 Optical Society of America