Abstract: A water-tight fiber optic ribbon communications cable constructed without the use of gel or grease in the buffer tube(s) thereof. A plurality of water-blocking yarns are provided around at least a portion of the stack of fiber optic ribbons loosely positioned within the buffer tube(s) that possess water swellable characteristics. The swell capacity of the plurality of water blocking yarns exceeds the critical mass of water that could enter the buffer tube(s) by a factor of 2.0 or more. Optionally, superabsorbent powder can be applied between and/or on the fiber optic ribbon stack.

Abstract: A fiber optic cable (10) having a tube assembly (20) therein. Tube assembly (20) includes an optical fiber group (22) in a tube (21). Optical fiber group (22) comprises a medial optical fiber subgroup (23) and lateral optical fiber subgroups (24a, 24b;25a,25b;26a,26b) adjacent thereto. Subgroups (24a,24b;25a,25b;26a,26b) define a step-like profile for maximizing optical fiber packing density of tube assembly (20) and/or defining a high fiber count cable (10). In exemplary embodiments, a diagonal free space is defined as the tube inner diameter minus the diagonal length of the cross-section of the profile of the optical fiber ribbon stack, the diagonal free space being about 2 mm to about 5 mm. In a multi-tube embodiment, diagonal free space can be about 0.5 mm to about 2 mm. In other embodiments, corner fibers can have a delta optical attenuation of less than about 0.05 dB/Km for a wavelength of @1550 nm over a 100 meter length 40″ to 70″ drum at room temperature.

Abstract: A fiber optic cable includes a buffer tube, a plurality of ribbons of optical fibers extending through the buffer tube and a grease layer disposed between at least one pair of adjacent ribbons. The grease layer includes a base component and a plurality of agglomerates formed filler particles, such as silica particles. The major dimension of the majority of the agglomerates is advantageously less than 100 microns in order to reduce microbending of the optical fibers and the resulting attenuation of the signals propagating along the optical fibers. The fiber optic cable can also include a filling compound that is disposed within the buffer tube and surrounds the optical fibers and that is also formed of a base component and a plurality of agglomerates, the majority of which similarly have a major dimension of less than 100 microns.

Abstract: An arrangement for monitoring the integrity of the spare fibers within a fiber optic cable includes a transmitter unit at a first location and a receiver unit at a second location (which may be upwards of 50 miles from the first location). A test signal is launched by a laser source in the transmitter unit along each spare fiber, and a set of threshold detectors is used at the receiver unit to monitor the received signal level. If the level of a received test signal along a spare fiber drops below a predetermined level (or if the fiber fails completely), an alarm signal is generated to alert a technician regarding the need to repair or replace the failed spare fiber. The alarm signal may be a “local” alarm signal generated at the second/receiver location or may be communicated back to the first/transmitter location as a “remote” alarm signal.

Abstract: A hybrid strength member (300) for an optical cable (10) is made from dielectric materials, and provides excellent compressive and tensile properties within a single structure. The strength member includes two concentric layers of filamentary strands that are embedded in a thermoset material such as epoxy. The filamentary strands of the inner layer (310) primarily comprise aramid fibers, while the filamentary strands of the outer layer (320) primarily comprise glass fibers. A pair of strength members (300-1, 300-2) is embedded in a plastic jacket of the optical cable at diametrically opposite sides of a central core tube that contains a number of optical fibers. Each strength member includes a thin coating (330) of a relatively soft material (i.e., a hardness of less than 80D on the Shore durometer scale) to enhance its coupling to the plastic jacket.

Abstract: A buffer tube design that allows easy access to signal carrying fibers disposed within the buffer tube with risk of damaging the signal carrying fibers. The buffer tube can be made with a ripcord disposed within. Additionally, the buffer tube has the mechanical properties that allow the ripcord to be pulled through the tube wall with less energy than is required to bend the signal carrying fibers within. The buffer tube can also be designed without a ripcord in such a way that the mechanical properties allow the tube to be hand torn using a lower amount of energy than required to bend the signal carrying fibers within.

Abstract: The present invention relates to a tube-enclosed optical cable containing ribbon units, and more specifically to a tube-enclosed optical cable containing ribbon units which can improve the economical efficiency of the process by simplifying the manufacturing process of optical cable and at the same time can improve the water blocking capability and compression characteristics of optical cable, providing optical cable characterized by coating particularly the central member of the cable with an absorptive substance and optical cable characterized by inserting interstices coated with an absorptive substance into the empty spaces between one more tubes encircling the central member and the sheath enclosing the tubes.

Abstract: A fiber optic cable having optical fibers disposed in buffer tubes, the buffer tubes defining at least two layers generally stranded about a center area of the cable. The buffer tube layers define a relatively inner layer of buffer tubes being closer to the center area, and an outer layer of buffer tubes being relatively further from the center area. The inner and outer buffer tube layers each having a respective helix value, the respective helix values being substantially the same. Alternatively, the respective helix values can be substantially non-equal. In addition, fiber optic cable systems including balanced helix factors have optical connections between layers of buffer tubes of the respective cables.

Abstract: The present invention relates to a cable, in particular an optical fiber cable, which is resistant to the radial permeation and to the longitudinal propagation of water. This cable contains a water-soluble polymer material which is a water-swellable and water-soluble material. In particular, this cable is characterized in that, following the ingress of water into this cable, the propagation of water is impeded on account of the combined effect of the swelling of the water-soluble material and the formation of an aqueous solution of said material which has a predetermined viscosity, so as to impede the passage of the residual water. Preferably, the water-soluble material is chosen from polyacrylamide, modified polyvinyl alcohol, vinyl alcohol/vinyl acetate copolymers, polyvinylpyrrolidone, and mixtures thereof, the material preferably being a vinyl alcohol/vinyl acetate copolymer.

Abstract: A conduit sleeve structure for use with fiber optic cables, coaxial cables and the like includes a pair of adjacent strip-shaped layers of flexible material that are joined along their longitudinal edges to define a channel through which the cable can extend longitudinally through the innerduct structure between the layers. The adjacent layers have differing widths between their longitudinal edges, whereby the wider layer bulges away from the narrower layer to impart an open configuration to the channel. It has been found that the conduit sleeve structure may be manufactured more efficiently and inexpensively if multiple sheets and pull cords are stacked and arranged in such a way that multiple conduit sleeve structures may be manufactured simultaneously in a parallel arrangement. The method of manufacturing the conduit sleeve structures includes feeding several stacked sheets through a folding machine or mechanism, a stitching machine, and then a slitting machine.

Abstract: Fiber optic conduits are received around a central axis with their axes extending in the same direction as the central axis and with each fiber optic conduit tangent to two other fiber optic conduits. The fiber optic conduits defme a central interstitial space therebetween and a plurality of outer interstitial spaces between each pair of fiber optic conduits on a side thereof opposite the central interstitial space. A central interstitial member is received in the central interstitial space tangent to the fiber optic conduits and an outer interstitial member is received in each outer interstitial space tangent to the pair of fiber optic conduits defining the outer interstitial space. The central interstitial member has a larger modulus of elasticity than each outer interstitial member.

Abstract: Optical fiber cable with a central strength member structure and with four or five buffer tubes each loosely receiving optical fiber ribbons in a stack and is disposed around and contacting the strength member. The optical fiber count is in excess of 1000 and the fill factor is not greater than 85% in a two inch duct. Each buffer tube contacts adjacent buffer tubes, and the buffer tubes are encircled by a jacket. Optionally, spaces bounded by pairs of buffer tubes and the jacket have optical fibers therein and can also include flexible longitudinal strength members and/or water blocking filaments. Preferably, the strength member structure and/or the buffer tubes are encircled by a water blocking tape. The optical fiber ribbons in the stacks can include different numbers of fibers, and hence, can have different width.

Abstract: An optical fiber cable enabling a reduction of diameter of the cable, without increasing the manufacturing cost, and improved in work efficiency when pulling out cores in the middle of the cable for cable connection work etc., provided with a tape core stack comprised of a stack of a plurality of tape cores each comprised of an integral assembly of a plurality of optical fibers arranged in parallel and embedded in a resin, at least one fiber cord member wound around an outer circumference of the tape core stack along its longitudinal direction, and a sheath formed outside of the tape core stack and the fiber cord member wound around the outer circumference of the tape core stack.

Abstract: An air blown fiber tube cable having improved thermal stability in contrast to conventional air blown fiber (ABF) tube cables and within which one or more air blown optical fiber units can be installed. The air blown fiber tube is formed from a cross-linked polyolefin (preferably cross-linked high density polyethylene) comprising at least one non-polymer filler material having a coefficient of thermal expansion less than the coefficient of thermal expansion of said tube.

Abstract: A water-tight fiber optic ribbon communications cable constructed without the use of gel or grease in the buffer tube(s) thereof. A plurality of water-blocking yarns are provided around at least a portion of the stack of fiber optic ribbons loosely positioned within the buffer tube(s) that possess water swellable characteristics. The swell capacity of the plurality of water blocking yarns exceeds the critical mass of water that could enter the buffer tube(s) by a factor of 2.0 or more. Optionally, superabsorbent powder can be applied between and/or on the fiber optic ribbon stack.

Abstract: A cable having improved performance during temperature fluctuations includes an outer sheath with a central cavity that does not have a centrally located anchoring member. A plurality of buffer tubes are provided in the central cavity. At least one optical fiber is provided in each of the buffer tubes. The buffer tubes are coupled together to prevent slippage between the buffer tubes, thereby forming a core unit. An adhesive may be provided to couple together the buffer tubes. Alternatively, the buffer tubes may be fused together.

Abstract: A fiber optic cable with at least one optical transmission component having a nominal radius, and at least two strength components, at least one of the strength components being generally adjacent to the optical transmission component. At least one of the strength components having a nominal radius that is less than the nominal radius of the optical transmission component. A cable jacket surrounds the optical transmission component and the strength components. The optical transmission component being generally disposed adjacent generally flat surfaces of the cable jacket. The cable can be made by an extrusion tooling apparatus with a tip and a die, the extrusion tooling apparatus being operative to extrude jacketing material about the strength components and the optical transmission component. The tip has an orifice defined within the end of the tip for receiving the strength and optical transmission components therein.

Abstract: The present invention includes an optical fiber cable configuration comprising fibers that are grouped into buffer tubes or buffer cells, containing fiber bundles or ribbon stacks, using a lightweight fabric-type composite tape material to serve as a light-weight strength member and protective low-thermal-expansion sheath. A plurality of the buffer tubes or buffer cells of various shapes are then positioned upon another piece of composite tape material. Gel or foamy glue is placed on the tape and is used to secure the buffer tubes to the tape. A triangular or trapezoidal stack is then formed by rolling the tape to enclose the buffer tubes and excess gel serves to fill in gaps. Multiple stacks may then be stranded to form a larger super-cable structure that uses a piece of composite tape material along with the rolling process, as described above, to support the individual stacks.

Abstract: The invention relates to an optical fiber cable including an outer sheath containing a plurality of optical fibers separated into at least two optical fiber modules, each of said modules consisting of a module sheath surrounding a respective group of optical fibers. According to the invention, the module sheath is formed by a film of plastics material. The film is, for example, wrapped widthwise around the group of optical fibers, a first face of the film being superposed on and fixed to a second face of the film over a portion of given width of said film.

Abstract: An optical fiber cable having a tube in which is inserted at least one optical fiber and a mixture of a water-mediated expanding powder and a material with a particle size less than that of the water-mediated expanding powder is inserted in the tube. The percentage of the powder in the mixture is in an amount such as to block the flow of water to within a distance of less than about three meters from the point of ingress of the water in twenty-four hours and such as to bring about an increase in attenuation in the optical fiber, after it has been housed in the cavity, of less than 0.02 dB/km.

Abstract: In a method of manufacturing an optical fiber cable comprising optical fiber units 12 disposed within an extruded sheath 14 with water absorbent powder 16 being provided between the optical fiber unit or units and the sheath, the fiber units pass through an extruder cross-head 36 extruding said sheath 14 together with a tape 22 transporting the water absorbent powder 16. The tape is formed upstream of said extruder crosshead 36 into a channel into which said water absorbent powder is delivered and the tape is adhered to the inside surface 24 of said sheath 14 by fusion thereto.

Abstract: A flexible innerduct structure is configured to contain a cable within a conduit. The innerduct structure includes a pair of adjacent strip-shaped layers of flexible material that are joined along their longitudinal edges to define a channel through which the cable can extend longitudinally through the innerduct structure between the layers. The adjacent layers have differing widths between their longitudinal edges, whereby the wider layer bulges away from the narrower layer to impart an open configuration to the channel. Other features of the innerduct structure relate to the material of which it is formed. Such features includes the structure of the material, such as a woven structure, and further include properties such as melting point, tensile strength, elongation, coefficient of friction, crimp resistance and compression recovery.

Abstract: An assembly that includes a fiber-containing structure that contains a plurality of optical fibers and a furcation tube assembly that includes a plurality of loose tube optical fiber cables. Each of the loose tube optical fiber cables includes a hollow inner tube; a support structure that includes strength members, the support structure surrounding the hollow inner tube; and, a protective jacket surrounding the support structure. The assembly further includes a heat shrink tube that joins the fiber-containing structure and the furcation tube assembly and a protective tube surrounded by the heat shrink tube and disposed in surrounding relationship to the furcation tube assembly. The support structure extends in a first direction between an outer surface of the fiber-containing structure and an inner surface of the protective tube proximate a first end of the protective tube.

Abstract: A fiber optic cable product is provided that includes a strength member and an elongate cable core surrounding and mechanically coupled to the strength member. The cable core defines a number of lengthwise extending slots for receiving optical fibers and a number of voids proximate the strength member that also typically extend lengthwise therethrough. The fiber optic cable product is therefore relatively lightweight and flexible. In order to insure that the mechanical properties of the fiber optic cable product are uniform, the cable core typically defines the voids in a generally symmetrical manner about the central strength member. A method and an apparatus for extruding a fiber optic cable product that includes a cable core defining a plurality of voids are also disclosed.

Abstract: A flexible innerduct structure is configured to contain a cable within a conduit. The innerduct structure includes a pair of adjacent strip-shaped layers of flexible material that are joined along their longitudinal edges to define a channel through which the cable can extend longitudinally through the innerduct structure between the layers. The adjacent layers have differing widths between their longitudinal edges, whereby the wider layer bulges away from the narrower layer to impart an open configuration to the channel. Other features of the innerduct structure relate to the material of which it is formed. Such features includes the structure of the material, such as a woven structure, and further include properties such as melting point, tensile strength, elongation, coefficient of friction, crimp resistance and compression recovery.

Abstract: A buffer encasement has a longitudinally extending interior surface that extends around and defines a longitudinally extending passage containing a stack of optical fiber ribbons. The interior surface closely bounds the stack, and the buffer encasement is easily removable from the stack. The buffer encasement can be is easily removable from the stack because the buffer encasement is thin and is constructed of a material that is capable of being easily torn. The buffer encasement can be is easily removable from the stack because the buffer encasement defines a longitudinally extending weakened portion that is capable of being more easily torn than the remainder of the buffer encasement. The weakened portion is operative so that when the weakened portion is torn the buffer encasement defines longitudinally extending edges on the opposite sides of the tear. The edges can be separated from one another to define an opening therebetween through which the stack of optical fiber ribbons can be accessed.

Abstract: The present invention relates to a cable, in particular an optical fiber cable, which is resistant to the radial permeation and to the longitudinal propagation of water. This cable contains a water-soluble polymer material which is a water-swellable and water-soluble material. In particular, this cable is characterized in that, following the ingress of water into this cable, the propagation of water is impeded on account of the combined effect of the swelling of the water-soluble material and the formation of an aqueous solution of said material which has a predetermined viscosity, so as to impede the passage of the residual water. Preferably, the water-soluble material is chosen from polyacrylamide, modified polyvinyl alcohol, vinyl alcohol/vinyl acetate copolymers, polyvinylpyrrolidone, and mixtures thereof, the material preferably being a vinyl alcohol/vinyl acetate copolymer.

Abstract: The optical fiber cable includes an assembly of at least two flexible tubes accommodating optical fibers, a sheath enveloping the assembly of tubes, and at least one filamentary form strength member at the periphery of the assembly of tubes. The tubes preferably extend in the sheath in a helical or an SZ assembly. The tubes are stuck together. The sheath is preferably made of polyethylene and the tubes are preferably made of polyvinyl chloride (PVC) or a thermoplastics elastomer with diol flexible segments. In this method, when extruding the sheath around the tubes, the temperature at which the material of the sheath is extruded is adjusted to cause the tubes to stick together.

Abstract: A self-supporting fiber optic cable includes messenger and carrier sections and at least one interconnecting web. The messenger section includes at least one support member and a protective jacket. The carrier section includes a tube, at least one optical fiber disposed within the tube, and a jacket. In order to protect the optical fiber from tensile forces and to facilitate mid-span access, the carrier section can have an overlength. In order to accommodate the overlength, the web can include a plurality of intermittent webs that permit the carrier section to bend. The carrier section can also include at least one strength member. The at least one strength member is preferably positioned in a reference plane that also generally extends through the messenger section, the carrier section and the web. By appropriately positioning the strength members relative to the tube, the carrier section preferentially bends in a plane generally orthogonally disposed to the reference plane.

Abstract: Composite cables operative to transmit information in electrical and/or optical transmission modes. The cables can include an electrical coaxial conductor comprising a generally central electrical conductor in a dielectric matrix. At least one optical transmission component is integrated with the matrix. The matrix can include at least two optical transmission components disposed on generally opposed sides of the central electrical conductor. Any optical transmission component can be substantially mechanically de-coupled from the matrix. In addition, the matrix can include at least one ripcord, and an indicia can be formed on the matrix for locating the position of an optical transmission component. The composite cables can include structural features for imparting a preferential bend to the cable.

Abstract: An optical module includes a stack of optical fiber ribbons that are within a buffer encasement, such as a thin sheath, that closely bounds the periphery of the stack. The optical modules can be rectangular, so that the optical modules can be readily stacked in a manner that results in a very space efficient fiber optic cable. The optical modules can be tested prior to being incorporated into the fiber optic cable so as to maximize the probability of the fiber optic cable being fully operable. The sheath cushions all of the sides of the stack. In some optical modules, the stack is movable relative to the sheath and the optical fiber ribbons are movable relative to one another.

Abstract: An improved optical fiber cable in which the threads that hold the various fiber groups together is made of a water swellable material and is color coded to allow the various fibers of the optical cable to be distinguished from each other. The optical fiber cable, includes a plurality of optical fiber groups, each groups including a plurality of optical fibers; a first water swellable material wrapped around a first group and a second water swellable material wrapped around a second group, wherein the first water swellable material has a color which is different from a color of the second water swellable material so as to allow optical fibers of the first group to be distinguished from optical fibers of the second group; and a sheath holding the plurality of optical fiber groups together. The optical fiber cable further includes a buffer tube in which the plurality of optical fiber groups are disposed arranged such that the sheath surrounds the buffer tube.

Abstract: A fiber optic cable includes multiple differently sized stacks of optical fiber ribbons. The stacks include a central stack that is approximately centrally located in a jacket passage and peripheral stacks positioned radially around the central stack. A difference exists between the dimensions of the central stack and the dimensions of one or more of the peripheral stacks. Another fiber optic cable has multiple longitudinally extending stacks of optical fiber ribbons that are within a jacket passage. The stacks include a central stack that is approximately centrally located in the jacket passage, and peripheral stacks positioned radially around the central stack. Buffer encasements that respectively contain the peripheral stacks are longitudinally stranded around the central stack.

Abstract: A fiber optic cable is provided with a thermal shield which consists (proceeding outward from the cable) of a temperature insulating layer of a foam plastic such as polyethylene, a plastic film wrap such as aluminized nylon, a metallic braid such as tinned copper and an outer jacket of plastic as additional temperature insulation and to facilitate pulling the cable. The film wrap and outer jacket are optional. For further shielding a second layer of foam plastic may be positioned outside the first metallic braid followed by a second plastic film wrap, a second metallic braid and an outer plastic jacket. If the shielded cable is near a source of heat, such as a hot water pipe or an air conditioning duct, the fiber optic cable temperature is uniform throughout its cross-section. Without the thermal shield instability of the signals in different fibers may occur because of heat differential.

Abstract: A flexible innerduct structure is configured to contain a cable within a conduit. The innerduct structure includes a pair of adjacent strip-shaped layers of flexible material that are joined along their longitudinal edges to define a channel through which the cable can extend longitudinally through the innerduct structure between the layers. The adjacent layers have differing widths between their longitudinal edges, whereby the wider layer bulges away from the narrower layer to impart an open configuration to the channel. Other features of the innerduct structure relate to the material of which it is formed. Such features includes the structure of the material, such as a woven structure, and further include properties such as melting point, tensile strength, elongation, coefficient of friction, crimp resistance and compression recovery.

Abstract: A communications cable network, in a duct or tube system used primarily for other purposes, wherein the communications cables are mounted on the walls of the duct or tube system. The communications cable (3), is made of a core (7-10) and a sheath (11). The core (7-10) of the communications cable (3) is extremely flexible and the sheath (11) is sufficiently rigid that cable sag is less than 20 mm for a 2000-mm distance between fastenings. The sheath (11) is removed from the core (7-10) in the area of the shafts (2) of the duct or pipe system (1).

Abstract: A fiber optic cable having optical sub-units each respectively including at least one optical fiber ribbon. The optical sub-units are removably connected together by a web of jacketing material. The optical fiber ribbons are generally twisted about their respective longitudinal axes by stranded strength fibers disposed about the optical ribbons. The fiber optic cable can be used as a stand alone component or, for example, in fan-out or break-out cables.

Abstract: An optical fiber cable includes a central strength or structural member, buffer tubes of the desired flexibility are S-Z wound around the central member with a predetermined lay, preferably with alternating single turn S-Z lays and the buffer tubes loosely receive optical fiber ribbon stacks, the pitch of the twist being selected to provide a predetermined ratio of the pitch of the buffer tube lay. The wall thickness of the buffer tubes is selected to provide the desired buffer tube strength and crush resistance, and the diameters of the buffer tubes bores are selected in relation to the size of the optical fiber ribbon stacks so as to provide a predetermined clearance. The clearance C is between about 1 mm and about 2 mm with the relation: C=(TI2−WR2)½−HR Where TI is the inner diameter of the tube, WR is the width of said stack and HR is a thickness of the stack.

Abstract: Described is an optical cable or cable element with a plurality of optical waveguide elements which are stranded together and each consist of several optical waveguides, collected into a bundle, and of a plastic covering surrounding the bundle with a maximum free space of 0.1 mm, and of a non-compressible filling compound filling the intermediate spaces between the optical waveguides, and with a layer of longitudinally aligned glass or plastic fibers surrounding the optical waveguide elements and with an extruded outer jacket of a polymer, the outer jacket compressing the layer radially.

Abstract: A preferred embodiment of the cable of the present invention incorporates a core, an outer jacket surrounding the core, and a super-absorbent foam disposed between the core and the outer jacket as well as inside the core. The super-absorbent foam comprises a polyurethane or similar type foam loaded with super-absorbent polymers (SAPs) which exhibit both water-blocking and flame-retarding characteristics. Additionally, the foam preferably is provided with a moisture content of greater than approximately 0 percent, by weight, thereby improving the flame-retarding characteristics of the foam.

Abstract: An optical fibre cable includes at least one optical fibre and a polymer-based outer sheath, characterized in that the sheath is an extruded double-layer sheath, including an extruded first inner polymer layer and an extruded second outer polymer layer. The first inner polymer layer is substantially devoid of tracking resistance, and the second outer polymer layer has high tracking resistance. The second outer polymer layer includes a polymeric mixture containing a polymer and an inorganic oxide or hydroxide in an amount of at least 40% by weight with respect to the total weight of the second outer polymer layer.

Abstract: A fiber optic cable (10) having a tube assembly (20) therein. Tube assembly (20) includes an optical fiber group (22) in a tube (21). Optical fiber group (22) comprises a medial optical fiber subgroup (23) and lateral optical fiber subgroups (24a, 24b; 25a, 25b; 26a, 26b) adjacent thereto. Subgroups (24a, 24b; 25a, 25b; 26a, 26b) define a step-like profile for maximizing optical fiber packing density of tube assembly (20) and/or defining a high fiber count cable (10). In exemplary embodiments, a diagonal free space is defined as the tube inner diameter minus the diagonal length of the cross-section of the profile of the optical fiber ribbon stack, the diagonal free space being about 2 mm to about 5 mm. In a multi-tube embodiment, diagonal free space can be about 0.5 mm to about 2 mm. In other embodiments, corner fibers can have a delta optical attenuation of less than about 0.05 dB/Km for a wavelength of @1550 nm over a 100 meter length 40″ to 70″ drum at room temperature.

Abstract: A fiber optic cable that includes an armor layer having inner and outer surfaces and defining a passageway therethrough, a protective jacket surrounding the armor layer, a plurality of optical fibers extending lengthwise through the passageway, and a water swellable element for inhibiting water migration through the passageway. The water swellable element can be a water swellable layer on at least one of the inner and outer surfaces of the armor layer and/or a water swellable yarn extending through the passageway. The fiber optic cable is preferably tubeless, i.e., free of buffer tubes. In instances in which a water swellable layer is on the inner surface of the armor layer, the optical fibers are capable of contacting the water swellable layer.

Abstract: A cable includes an optical fiber, a buffer tube having the optical fiber arranged therein, and a thermoset material for connecting the optical fiber to the buffer tube. The thermoset material will not melt or appreciably soften and will maintain basic elastomeric flexibility in a temperature range of −40 to 70 degrees Celsius. The thermoset material may be a flame-retardant silicone elastomer, base and curing agent, as well as a liquid rubber molded compound, which is not flame-retardant. The thermoset material allows for fiber helix movement as the cable expands and contracts from −40 to +70 degrees Celsius, and is cyclically placed for connecting the optical fiber to the buffer tube at intervals of about every ½ meter, as well as at intervals of about every 10 meters.

Abstract: Fiber optic and composite zip cord cables (40;50) having at least one respective buffer unit (30) therein. Each zip cord (40;50) includes at least two cords (42;52,54) having respective jackets (46;56) attached by a frangible web (43;53). At least one cord includes a buffer unit (30) generally surrounded by a layer of filaments, the buffer unit comprising at least two optical fibers (31) in a buffer layer (32). The buffer units (30) can be stranded about a central member (22) and enclosed in a jacket (28).

Abstract: A fiber optic cable comprising a plurality of tubes each having at least one optical fiber therein and at least one strength component. A center of the strength component being generally offset from a center-zone of the fiber optic cable. The fiber optic cable includes a center-zone interstice, the center-zone interstice spanning generally the center of the fiber optic cable between the tubes and the strength component. The center-zone interstice may include a water swellable substance for blocking the flow of water therein.

Abstract: In a device for placing a structural element in a cable installation conduit in order to sub-divide it, the structural element has a width close to the size of the internal perimeter of the conduit and comprises a plate surmounted by ribs. The device comprises a hot air inlet designed to soften the plate of the structural element; an external cylinder whose diameter is identical to that of the conduit, the cylinder comprising a shaping cone at one end in order to enable the softened structural element in order to gradually take a cylindrical shape; and an internal core fixedly held at a position located in the shaping cone of the external cylinder and positioned inside the softened structural element in order to give it a constant internal diameter when it is being shaped.

Abstract: An optical fiber cable in which optical fiber ribbon stack can be accommodated in a cylindrical space efficiently and which has excellent loss characteristic. A plurality of optical fiber ribbons 1 are stacked. Cushioning fillers 2 are disposed around the optical fiber ribbon stack 1. The optical fiber ribbon stack 1 and the cushioning fillers 2 are accommodated in a cylindrical member 3. The space factor of the cushioning fillers in the inner space of the cylindrical member as a remainder after removal of the optical fiber ribbon stack from the inner space is from 10 to 60%. Consequently, the optical fiber cable becomes excellent both in initial transmission loss and in loss increasing characteristic at a low temperature.

Abstract: An optical fiber cable which is constructed so as to minimize optical transmission loss, and which comprises one or more compliant core units retained within a surrounding sheath. Each compliant core unit is composed of a bundle of parallel optical fibers, such as a stack of ribbons, enclosed in and supported by a compliant unitizing structure. The structure may derive its compliance from a foamed material, such as polyethylene, that is extruded to surround the fiber bundle. The foam material sufficiently cushions the bundle of fibers from external stresses that are applied when the cable is bent or encounters compressive loading.

Abstract: A high mechanical and heat performance optical cable for aerial or underground applications comprises a dielectric central member, a plurality of polymeric tubes helically arranged around the dielectric central member, a plurality of optical fiber loosely housed in the polymeric tubes and separated from the polymeric tubes by a filling, a binder comprising polymeric tapes helically arranged around the tubes, a peripheral pulling element arranged around the polymeric tubes, a flame resistant external sheath surrounding the peripheral pulling element, and metallic elements helically arranged around the flame resistant external sheath to form an external ring.