Optical fibre cable with intermediate separation layer - compensates contraction differences between outer sheath and inner buffer layer during mfr.

摘要

The cable has the optical fibre (GS) surrounded by a soft buffer layer (PO) and a relatively stiff outer sheath (SH). A separation layer (TS) between the buffer layer (PO) and the outer sheath (SH) and allows the relative movement of the buffer layer (PO) for compensating movement due to temp. variations. The separation layer (TS) may comprise a paper or foil covering applied to the outside of the buffer layer (PO) by a spinning or drawing process. Alternatively the separation layer (TS) comprises a fluidic mass, e.g. containing oil. The cable may comprise a glass fibre core (GF) of 0.12mm dia., with a silicon rubber buffer layer (PO) of 0.3mm dia. and a polypropylene sheath (SH) of 1mm dia., the separation layer (TS) comprising a petroleum mass and having a thickness of between 30 and 60 microns. The buffer layer (PO) and the sheath (SH) are provided by respective extrusion processes. The inclusion of the separation layer (TS) simplifies cable mfr.