Abstract: Disclosed is a novel central-tube cable with high-conductivity conductors. The novel central-tube cable according to the present invention yields a fiber optic cable with a smaller diameter than found in stranded-tube-cable designs. The central-tube cable features (i) a buffer tube containing optical conductors, (ii) radial strength members, and (iii) high-conductivity conductors coated with a dielectric material, such as polypropylene. The dielectric coating helps to prevent the high-conductivity conductors from shorting.

Abstract: A method of controlling flow includes treating a region of a surface to have a non-wettable surface characteristic or a wettable surface characteristic in the region.

Abstract: A process for producing an optical fiber cable composite structural component, such as reinforcing members, buffer tubes, filler rods, jackets, and slotted cores, is disclosed. The composite structural components are produced by co-extruding a thermotropic liquid crystalline polymer (TLCP) and a thermoplastic matrix material into the composite structural component so that TLCP reinforcing fibrils are dispersed in the thermoplastic matrix material. The TLCP reinforcing fibrils undergo a high level of process induced orientation, are provided with a high aspect ratio, and small diameters. The composite structural component has a high modulus. The TLCP reinforcing fibrils may be made continuous or discontinuous.

Abstract: A process for producing an optical fiber cable composite structural component, such as reinforcing members, buffer tubes, filler rods, jackets, and slotted cores, is disclosed. The composite structural components are produced by co-extruding a thermotropic liquid crystalline polymer (TLCP) and a thermoplastic matrix material into the composite structural component so that TLCP reinforcing fibrils are dispersed in the thermoplastic matrix material. The TLCP reinforcing fibrils undergo a high level of process induced orientation, are provided with a high aspect ratio, and small diameters. The composite structural component has a high modulus. The TLCP reinforcing fibrils may be made continuous or discontinuous.

Abstract: An aerial drop cable comprises a jacket surrounding a cavity containing a least one loosely housed optical fiber and a pair of reinforcing members composed of a plurality of high modulus fibers such as polybenzoxazole (PBO) fibers. The cross-sectional area of the reinforcing members is larger than the cross-sectional area of the cavity so that the optical fiber disposed in the cavity is protected from lateral compressive forces. By utilizing reinforcing members which are composed of PBO fibers, the diameter of the reinforcing members is reduced as compared with conventional reinforcing members composed of aramid, metal or glass thereby providing a substantial reduction in the amount of jacketing material and the weight of the cable. Further, the bending strain of the cable utilizing PBO reinforcing members is substantially reduced for an equivalent bending radius as compared with cables utilizing conventional reinforcing members due to the smaller diameter of the reinforcing members.

Abstract: An optical-fiber cable includes an assembly of buffer tubes including at least two flexible buffer tubes that are held together compactly by adhesion to one another. The cable further includes a plurality of optical fibers, which are housed within the buffer tubes, a jacket surrounding the assembly of buffer tubes, and at least one longitudinal strength member that is provided at the periphery of the assembly of buffer tubes. According to one aspect, the jacket is formed of polyethylene, the buffer tubes are formed of polyvinyl chloride (PVC) or a thermoplastic elastomer possessing flexible diol segments, and the buffer tubes are contained within the jacket in a helical or SZ stranding configuration. According to a second aspect, a fiber optic buffer tube includes low and high melting point materials forming domains and a matrix, respectively, and preferably further includes a filler. The domains are embedded in the matrix. The latter buffer tubes are bonded together by thermal activation of the domains.

Abstract: A process for producing an optical fiber cable composite structural component, such as reinforcing members, buffer tubes, filler rods, jackets, and slotted cores, is disclosed. The composite structural components are produced by co-extruding a thermotropic liquid crystalline polymer (TLCP) and a thermoplastic matrix material into the composite structural component so that TLCP reinforcing fibrils are dispersed in the thermoplastic matrix material. The TLCP reinforcing fibrils undergo a high level of process induced orientation, are provided with a high aspect ratio, and small diameters. The composite structural component has a high modulus. The TLCP reinforcing fibrils may be made continuous or discontinuous.

Abstract: An optical-fiber cable includes an assembly of buffer tubes including at least two flexible buffer tubes that are held together compactly by adhesion to one another. The cable further includes a plurality of optical fibers, which are housed within the buffer tubes, a jacket surrounding the assembly of buffer tubes, and at least one longitudinal strength member that is provided at the periphery of the assembly of buffer tubes. According to one aspect, the jacket is formed of polyethylene, the buffer tubes are formed of polyvinyl chloride (PVC) or a thermoplastic elastomer possessing flexible diol segments, and the buffer tubes are contained within the jacket in a helical or SZ stranding configuration. According to a second aspect, a fiber optic buffer tube includes low and high melting point materials forming domains and a matrix, respectively, and preferably further includes a filler. The domains are embedded in the matrix. The latter buffer tubes are bonded together by thermal activation of the domains.

Abstract: A telecommunications cable element having a transmission element disposed in a buffer tube made from thermoplastic polyolefin elastomeric buffer material is disclosed. The polyolefin elastomeric buffer material has a modulus of elasticity below about 500 MPa at room temperature and a modulus of elasticity below about 1500 MPa at −40° C. Preferentially, the thermoplastic polyolefin elastomer material forming the buffer tube has an elongation to break below about 500% and a Melt Flow Index above about 3.

Abstract: A filler rod for occupying space in a stranded optical fiber communications cable having at least one buffer tube containing at least one optical fiber is disclosed. The filler rod comprises an elongated rod extruded from a polypropylene homopolymer, a polypropylene-polyethylene copolymer (i-PP) resin material, or preferably, from a polypropylene-polyethylene copolymer having a nucleating agent disbursed therein. The resin material is foamed during extrusion so as to have a plurality of void spaces therein and a relative density which is less than 1 relative to the unfoamed resin material. As compared to rods made from high density polyethylene, the i-PP filler rods show a greater foaming efficiency, more efficient use of material, an improved combination of mechanical properties and density, reduced post-extrusion shrinkage and a substantial reduction in the sticking of the filler rods to the outer jacket that is experienced with high density polyethylene filler rods.

Abstract: A telecommunications cable comprising a communications element, such as an optical fiber, and a jacket surrounding the communications element having at least one elongated strength member embedded therein is disclosed. The jacket of the telecommunications cable is formed by extruding a blend of a polyolefin material and a copolymer adhesion promoting material, such as graft copolymer of polyethylene and ethylene acrylic acid or a graft copolymer of polyethylene and maleic anhydride. The copolymer adhesion promoting material promotes adhesion between the strength member and the jacket. The resulting increase in adhesion between the strength member and the jacket improves the cable's resistance to water penetration, low temperature buckling and shrinkage as well as excessive high temperature expansion. The blending of an adhesion promoting material in the jacketing material also reduces the risk of armor cracking during cyclic flexing and strength member pistoning within the jacket.

Abstract: A water blocking gel which is compatible with polyolefin optical fiber cable buffer tubes is disclosed. The water blocking gel comprises a polyolefin oil, wherein only a very small fraction of the polyolefin species have a molecular weight below about 2000. The gel also includes a thixotropic agent, and a thermal oxidation stabilizer. The gel is relatively low cost, does not cause substantially swelling of the polyolefin buffer tubes in contact therewith and does not degrade the buffer tube's physical properties.

Abstract: A filler rod for occupying space in a stranded optical fiber communications cable having at least one buffer tube containing at least one optical fiber is disclosed. The filler rod comprises an elongated rod extruded from a polypropylene homopolymer, a polypropylene-polyethylene copolymer (i-PP) resin material, or preferably, from a polypropylene-polyethylene copolymer having a nucleating agent disbursed therein. The resin material is foamed during extrusion so as to have a plurality of void spaces therein and a relative density which is less than 1 relative to the unfoamed resin material. As compared to rods made from high density polyethylene, the i-PP filler rods show a greater foaming efficiency, more efficient use of material, an improved combination of mechanical properties and density, reduced post-extrusion shrinkage and a substantial reduction in the sticking of the filler rods to the outer jacket that is experienced with high density polyethylene filler rods.

Abstract: Optical fiber cable components such as buffer tubes, filler rods, or jackets are produced using a thermoplastic polyolefin characterized by a high melt flow index. The use of material with a high melt flow index versus conventional "extrusion grade" materials which are characterized by a low melt flow index results in substantial improvements in buffer tube crystallinity and crystallization rates, improved buffer tube crush resistance, reduced post extrusion shrinkage, improved gel compatibility, and improved excess fiber length control. The advantages of using materials with a high melt flow index are most evident when processing thermoplastic materials such as nucleated copolymers of ethylene and propylene at high line speeds (shear rates) of over 50M/min.

Abstract: A process for making thermoplastic thiourethane-urethane copolymers for use in making optical products preferably comprising reacting an aliphatic diisocyanate with a dithiol under polymerization conditions to form a thiourethane prepolymer which is then reacted with a diisocyanate such as methylene bis(phenyl isocyanate) and a polyol such as a diaromatic containing diol such as ethoxylated Bisphenol A or an aliphatic isocyanate reactive monomer such as tricyclodecane dimethanol or 1,4-dimethanol cyclohexane to form the copolymer product. The polymers have a combination of high refractive index and high Abbe No. The polymers also have high impact strength, high hardness and Tg's above 100.degree. C. It is preferred to make the polymer in an extruder.