Abstract: A connector is provided with an optical fibre in an axial through-bore. The bore opens into an enlarged recess at one end of the connector. A solid rod of a non-elastical ductile material is inserted into the recess. An axial force from outside the connector is applied to the rod, thereby expanding the rod radially to fix it in position in the recess. A hole is made in the rod with an accurate concentricity relative to the circumference of the connector. The optical fibre is inserted into the hole in the rod. Finally, a further axial force from outside the connector is applied to the rod for radial expansion thereof resulting in a reduction of the diameter of the hole in the rod and thereby obtaining an accurate concentric fastening of the optical fibre.