Abstract: An optical fiber for use in distributed vibration sensing has perturbations along its length. The perturbations may be applied externally to a mode field diameter of the optical fiber. Alternatively, the perturbations may be applied through the use of fusion splicing of fiber lengths that form the optical fiber.

Abstract: Elastic compression apparatus for loose tube used in fiber optic cables, comprising compression contacts for gripping the loose tube following extrusion, the loose tube being made of a first material having a predefined post-extrusion shrinkage, and the compression contacts being made of a second material, wherein the compression contacts are modified to provide a coefficient of friction between the two materials such that said compression contacts apply a radial pressure and an axial tension to said tube that cause elastic deformation only and do not cause plastic deformation. The tube may be extruded at a line speed rate that is relatively different from the optical fiber line speed rate, and causes elastic extension of the tube over the distance that would be covered by post-extrusion shrinkage.

Abstract: A method of coating a silica-silica optical fiber, comprising, in a single pass on a fiber coating machine: applying a primary layer of UV curable acrylate carrying a first color, on said fiber; and applying a second layer of UV curable acrylate carrying a second color different from the first color, on top of the primary layer, the second layer being applied in patterns over the primary layer. The method is used to identify fibers in bundles or loose tubes where there are more fibers than there are basic colors.

Abstract: A method of coating a silica-silica optical fiber, comprising, in a single pass on a fiber coating machine: applying a primary layer of UV curable acrylate carrying a first color, on said fiber; and applying a second layer of UV curable acrylate carrying a second color different from the first color, on top of the primary layer, the second layer being applied in patterns over the primary layer. The method is used to identify fibers in bundles or loose tubes where there are more fibers than there are basic colors.

Abstract: A communication cable for high-frequency data-transmission, includes a core including at least one group of twisted insulated conductors; an inner jacket of insulating polymeric material enclosing the core; and an outer jacket of a conductive polymeric material enclosing the cable core and inner jacket. The outer jacket has a sufficiently high electrical conductivity to substantially reduce electromagnetic interference, but not so high as to require grounding of the cable or to unduly attenuate the signal transmitted by the cable at the high-frequency data-transmission. Preferably, the conductive polymeric material has a resistivity in the range of 1.0×1010 to 1.0×1012 ?·cm, preferably about 1.0×1011 ?·cm.