Coherent multicarrier techniques in future broadband communication networks

Abstract

A multicarrier arrangement imposes certain requirements on the coherence of each laser wave in particular if a densely spaced (several GHz) carrier comb is assumed. In future there may be competition between direct detection systems with optical preamplifiers and single coherent systems for long distance transmission. Two questions have to be asked. Why multicarrier systems? Why coherent detection? The answers will differ, depending on the future evolution of components and system applications, which are examined briefly. Multicarrier transmission in the subscriber loop, multicarrier switching and problems related to multicarrier techniques are also discussed