A field demonstration of wavelength routed optical networks

These experimental demonstrations have taken wavelength routing from the laboratory into British Telecom's (BT's) London Main Optical Fibre Network. It shows the ability of this technique to form effective transparent optical networks. Components and sub-assemblies that are available commercially have been used throughout to emphasise the practicality of constructing the networks without the use of state of the art technology. The significant multiplexing and demultiplexing losses at the network nodes limit the range of basic wavelength routed networks. However, this demonstration has shown that useful ranges of up to 40 km for 622 Mbit/s data can be achieved even without amplification. With optical amplification, large networks are possible and in this demonstration amplification allowed transmission lengths of 88.8 km to be demonstrated for the 622 Mbit/s signals. This was achieved with an optical power margin of 12 dB. This distance corresponds to twice the diameter of the existing London Main Fibre Network.