Tensor Machinery Ltd.

Sumitomo Electric Fiber Optics Corporation

Randy G Schneider

Eric L Buckland

Paul E Neveux, Jr

Mahesh K Vyas

A loose tube element including a plastic sheath containing a grease-like material and an optical fiber or bundle of optical fibers or a ribbon of optical fibers is pulled from an extruder crosshead through a cooling bath and around a constant speed capstan. The loose tube element travels around the constant speed capstan a number of times and as it exits the capstan it is subject to a tensile force provided by a variable torque control capstan. The tensile force causes elongation of the plastic sheath, causes the optical fiber to be pulled taut and thereby controls the ratio of fiber length to sheath length within the loose tube element. While subjected to the tensile force, the element is subsequently cooled, causing the elongation of the plastic sheath to become permanent and thus fixing the fiber-to-sheath length ratio. The fiber-to-sheath length ratio is not affected by variation in production line speed and the production line may operate at very high speeds while producing loose tube elements with consistent fiber-to-sheath length ratios. The loose tube element is then stored on a take-up reel or is used as a stranding element or core element in a fiber optic cable.

Apparatus and method for sheathing optical fibers

A steam resistant optical fiber cable for use adjacent underground steam ducts in metropolitan locations. The optical fiber cable comprises polyethersulfone loose tubes for enhanced hydrolytic stability and a welded aluminum tube swaged over the fiber core to provide moisture imperviousness. The welded aluminum tube is bonded to the fiber core with an intermediate resin barrier layer to provide resistance to repeated cyclic flexing of the cable.

Growing community of inventors

Raleigh, NC, United States of America

Randy G Schneider