Protective metal tube or sleeve for an optical wave guide with specially spaced windings of the sleeve coils

摘要

The protective waveguide sleeve comprises a metal tube (2) which surrounds the waveguide and which cannot be compressed. The metal tube is made of a helix (5) of flat metal with a rectangular cross-section and with two sides parallel to the central axis of the tube. The helix is wound such that adjacent turns are spaced from each other. The distance between adjacent turns is between 1 and 3 per cent, preferably 5 per cent of the cross sectional dimension of the metal material in a direction parallel to the central axis of the tube.