WDM techniques in broadband optical networks

The penetration of optical-fibre technology into the local-access network may well occur by the economic provision of well-established services, such as basic telephony, over a shared-access optical architecture. The provision of new broadband services needs to be done without disruption to these basic (telephony) services. Wavelength-division multiplexing techniques allow the possibility of broadband upgrade on a shared-access network architecture without disturbing existing services. The nature of shared-access structures, although providing opportunities for the early economic provision of basic low-bit-rate services, gives rise to major implications for the requirements of the WDM technology used for upgrading to broadband operation. In this paper example network structures are examined in terms of possible upgrade strategies and the associated technological implications.