A European first-deployment of 10-Gbit/s TDM technology in the Energis network

Summary form only given. For Energis, the fiber infrastructure can support both STM16 wavelength-division multiplexing (WDM) and STM64 time-division multiplexing (TDM) technologies. Energis built the world's first SDH national network in 19 months, using the most advanced technology, throughout England and Wales by installing optical fiber cables primarily along the National Grid's electricity transmission infrastructure. Today the Energis fiber exceeds 5000 km of installed nondispersion-shifted fiber. Two methods have been used to install the optical fiber cable. The first involves replacing the existing earth wire with a new composite earth wire containing the fiber pairs and the second involves wrapping the optical fiber around the existing earth wire. These methods are used in conjunction with conventional buried cable fiber techniques. For Energis the move directly to 10 Gbit/s will enable it to provide significant expansion to the core capacity, while implementing cutting edge technology. Energis believes that both TDM STM64 (10 Gbit/s) and WDM STM16 have a place in the network and the two technologies, in fact, support one another.