The role of photonics technology in the implementation of future broadband telecommunications networks

The purpose of this paper is to investigate the role that photonics technology can play in the implementation of modern broadband telecommunications networks. Starting from the continuous growth of bandwidth demand that is observed due to the Internet and multimedia applications, the attractive features of photonics technology that have rendered fibre the primary transmission medium are underlined and the modern optical multiplexing techniques are presented. The perspectives of electronic switching are discussed with emphasis on the technical restrictions that are imposed by its use due to the inevitable optoelectrical conversions and the need for moving towards alloptical networks. The core element for achieving this goal, which is the nonlinear semiconductor optical amplifier (SOA)-based optical gate module, is analysed-in particular its potential to perform all-optical Boolean logic functions and to form the technology platform for the implementation of all-optical signal processing circuits with cost and performance advantages over the corresponding electronics. Finally, the impact that the photonics technology comprising these circuits is expected to have on the telecommunications industry is highlighted and the necessary conditions for its commercial exploitation in real communications networks are discussed.