Very high-density distribution cables for FTTH networks

To meet the special constraints of FTTH distribution networks, France Telecom now has at its disposal a range of appropriately modular and compact nonmetallic cables. The fibre density of the microsheath and ribbon modules have made them the ideal replacement for usual loose tube cable technology. These modules are grouped together in microsbeath bundles or a matrix of ribbons. If required, an assembly can be made from Very dense tubes which contain several microsheath bundles or a matrix of ribbons. In many cases, the outer sheath, reinforced by composite rods is directly extruded over the modules. Cable density is as high as 1.5 of/mm(2) for 512 fibres. Some cables have been made using fibres including 4 single mode cores. A 1.5 km 576 core cable is in operation on a demonstration link at CNET Lannion. Its density is 5 cores/mm(2).