Milan, 20 December 2005 – Scientists at Prysmian Cables & Systems in Italy have made a significant breakthrough in optical fibre design with the production of a reduced size, 200 micron diameter singlemode fibre - PrimaLightTM. The conventional diameter of optical fibres for telecom use has, for many years been 250 microns and almost all optical cables use this size of fibre in their construction.

However, as telecom networks continue to develop and the extent of fibre in these networks goes deeper towards the end user, the level of congestion in underground cable ducts, particularly in highly populated urban environments, is becoming a critical issue.

Manufacturers have made great efforts to reduce cable diameters through the use of improved manufacturing techniques and enhanced performance materials within the cable construction. This has helped the congestion problem considerably although the lower limits of cable diameter have now realistically been reached.

Now, by reducing to 200 microns the diameter of the fibre itself - the basic building block of any cable - an additional step-change in cable diameter is possible. Agusti Valls, Senior VP of Product Development and Quality for the Prysmian cable business stated: "This opens up tremendous possibilities on the cable design front. For example, with the PrimaLightTM fibre we can now include 16 fibres into a tube element that previously had a limit of 12. Alternatively, smaller tubes can be employed to hold similar fibre counts to those used previously. The effect on overall cable diameter is significant and for very high fibre count designs - commonly deployed in the access networks - overall diameter reductions exceeding 10% are possible.”

Dr Giacomo Roba - who leads the Fibre R & D activity added: "The 250 micron diameter has, for many years, been the de facto standard. However, with every other aspect of cable and fibre design under review we felt that this particular fibre parameter should be no exception. We are very pleased with the results of the work we have undertaken and we believe that with PrimaLightTM we have made a significant breakthrough which will have far-reaching effects."