Lucent Technologies Inc.

At&t Bell Laboratories

Fitel USA Corporation

At+t Corp.

Jim Jenqtsong Sheu

Peter A Weimann

Carl Raymond Taylor

Kenneth Wade Jackson

Clyde Jefferson Lever, Jr

Nathan E Hardwick, Iii

Richard Dalton Small, Jr

Richard Hartford Norris

Candido J Arroyo

Wayne McCall Newton

Carla Green Wilson

Mark I Shmukler

Jennifer R Meeks

James R Petisce

Terry D Mathis

Montri Viriyayuthakorn

Richard Norris

John F Malluck

David M Mitchell

David S Hancock

Stanley Kaufman

Robert J Brown

A cable of this invention includes a core comprising a plurality of coated optical fibers and a filling composition of matter that is disposed about the fibers. Typically, the fibers and the filling material are disposed within a tubular member that is disposed within a sheath system. The sheath system includes longitudinally extending strength members and a plastic jacket. The filling composition that fills interstices in the core is one that includes an oil constituent that is a relatively high molecular weight aliphatic hydrocarbon. A relatively small percent by weight of a stereochemically hindered antioxidant system is used to prevent thermal oxidative degradation of the filling material as well as of materials in contact with the filling material. Such stereochemically hindered antioxidants will not migrate out of filling material into other cable and fiber materials, thereby increasing their effectiveness. As a result, a relatively low concentration of antioxidant is needed, as compared with the amount used in the prior art. A styrene ethylene propylene copolymer is also included in order to reduce oil separation of the filling material. A colloidal filler is used to impart gel properties to the material.

Optical cable fiber provided with a non-migrating antioxidant

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. The buffer encasement can be in the form of a longitudinally extending piece of tape having longitudinally extending opposite edges defining an overlapping configuration so that the tape encloses the stack of optical fiber ribbons. The edges of the tape can be separated to provide a nonoverlapping configuration in which an opening is defined between the edges and through which the stack of optical fiber ribbons can be accessed. Therefore, the edges of the tape can be reclosed, if desired.

Groups of optical fibers closely bound by easily removable buffer encasements, and associated fiber optic cables

An optical fiber cable having a core which includes at least one optical fiber transmission medium, a sheath system which is disposed about said core, and a filling material disposed within said core. The filling material of the optical fiber cable includes both a hydrocarbon carrier means, and a thickening system disposed within the hydrocarbon carrier means. The thickening system may include an inorganic constituent, either alumina or fumed alumina, and a polymer.

Filling compound having alumina gelling agent

A preferred embodiment of the cable of the present invention incorporates a core, an outer jacket surrounding the core, and a commercially available super-absorbent fibers disposed between the core and the outer jacket as well as inside the core. The fibers may also be applied to a tape to be provided between the core and the outer jacket. The tape incorporates a first layer and super-absorbent fibers, with the super-absorbent fibers being applied to the first layer. Preferably, the first layer is formed of spun bonded non-woven polyester material, nylon spun bonded fabric, non-woven glass, polypropylene melt blown non-woven fabric, polyurethane spun bonded fabric, or TCF cellulose fabric, among others. Additionally, the fibers preferably are provided with a moisture content of greater than approximately 0 percent, by weight, thereby improving the flame-retarding characteristics of the tape.

Cables with water-blocking and flame-retarding fibers

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. The sheath is preferably sufficiently rigid to maintain the stack in a stacked configuration, and sufficiently flexible to allow the optical fiber ribbons to slide laterally relative to one another so that, in an end elevation view of the stack, the stack and the sheath can transition from a non-skewed configuration to a skewed configuration. The lateral displacement between the optical fiber ribbons in the skewed configuration is different from the lateral displacement between the optical fiber ribbons in the non-skewed configuration. The stack can be in a longitudinally twisted configuration, and the sheath is sufficiently rigid to hold the stack in the longitudinally twisted configuration. Further, the sheath can be thin such that the exterior surface of the sheath defines ridges that correspond to the twist of the stack.

Stacks of optical fiber ribbons closely bound by respective buffer encasements, associated methods, and associated fiber optic cables

A family of oil or fluid-based lubricants with an additive, for use in fabricating optical fiber cables having loose fibers or stacked optical fiber ribbons is disclosed. The additive, which can be either fumed silica, fumed alumina, or block polymers, lowers the surface tension and contact angle, and increases the viscosity and wettability of the lubricants.

Cable with lubricated optical fibers and process of lubricating optical fibers

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. Each buffer encasement includes a longitudinally extending interior surface that extends around and defines a longitudinally extending passage that contains the respective peripheral stack, and each interior surface closely bounds and engages a substantial portion of the periphery of the respective peripheral stack. Another fiber optic cable includes multiple optical modules within a longitudinally extending jacket and longitudinally stranded around a central member. Each optical module includes a stack of optical fiber ribbons enclosed in a buffer encasement. Each buffer encasement includes a longitudinally extending interior surface that extends around and defines a longitudinally extending passage that contains the respective stack, and the interior surface closely bounds and engages a substantial portion of the periphery of the respective stack.

Fiber optic cables with multiple stacks of optical fiber ribbons

The present invention generally is directed to compositions, products and methods that utilize superabsorbent polymers for flame-retarding. A preferred method includes improving flame-retarding characteristics in products by adding SAPs to the product. Prior to the step of adding the SAPs, the product exhibits a first limiting oxygen index and after the step of adding the SAPs, the product exhibits a second limiting oxygen index, with the second limiting oxygen index being higher than the first limiting oxygen index. Preferably, the SAPs can be pre-loaded with moisture, thereby potentially further increasing the flame-retarding characteristics of the product. In a preferred embodiment, the product is configured as a cable, with the outer jacket of the cable incorporating the SAPs.

Methods for flame-retarding and products produced therefrom

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.

Cables with water-blocking and flame-retarding foam

A family of lubricants for use in fabricating optical fiber cables having stacked optical fiber ribbons is disclosed. Each of the lubricants, is characterized by a surface tension less than 34 dynes per centimeter, a contact angle of less than 44 degrees and a viscosity appropriate for the cabling application.

Lubricant for central core fiber optic cable having stranded ribbons

A stack of optical fiber ribbons is enclosed in a buffer encasement having a relatively soft inner portion and an relatively hard outer portion. The inner portion has an interior surface extends around and defines a longitudinally extending passage that contains the stack, and the interior surface closely bounds the stack. The outer portion extends around, closely bounds and contacts the inner portion, and has a modulus of elasticity that is greater than the modulus of elasticity of the inner portion. In accordance with one example of the invention, the inner portion has an exterior surface that extends around and is spaced apart from the passage, and the outer portion has an interior surface that extends around, closely bounds, and engages the exterior surface of the inner portion, whereby the buffer encasement has multiple plies. In contrast, in accordance with another example of the invention, a surface is not defined between the inner portion and the outer portion.

Stacks of optical fiber ribbons closely bound by respective buffer encasements with relatively hard exteriors and relatively soft interiors, associated methods, and associated fiber optic cables

A preferred embodiment of the dry core optical fiber cable of the present invention incorporates a plurality of sub-units with each of said sub-units being arranged adjacent another of the sub-units so that the plurality of sub-units define an outer periphery. Preferably, each of the sub-units includes a plurality of optical fibers, a yarn layer and a sub-unit jacket, with each of the optical fibers being arranged adjacent another of the optical fibers. The sub-unit jacket surrounds the optical fibers, with the yarn layer being disposed between the optical fibers and the sub-unit jacket. An outer jacket surrounds the plurality of sub-units, with water-blocking tape being disposed between the outer jacket and the outer periphery of the sub-units. A method of manufacture of the cable also is provided.

Dry core optical fiber cables for premises applications and methods of manufacture

A preferred embodiment of the cable of the present invention incorporates a core, an outer jacket surrounding the core, and a tape disposed between the core and the outer jacket. The tape includes a first layer and superabsorbent polymers (SAPs) which are applied to the first layer. Preferably, the first layer is formed of spun bonded non-woven polyester material, nylon spun bonded fabric, non-woven glass, polypropylene melt blown non-woven fabric, polyurethane spun bonded fabric, or TCF cellulose fabric, among others. Additionally, the SAPs preferably are provided with a moisture content of greater than approximately 2 percent, by weight, thereby improving the flame-retarding characteristics of the tape.

Cables with water-blocking and flame-retarding tapes

An optical cable [100] having one or more optical fibers [11] that are surrounded by an improved filling material [10] is disclosed. The filling material includes one or more synthetic oil(s) that are present in an amount, which is 80 to 95 percent by weight of the filling material and which have an average molecular weight that is greater than about 350. The filling material further includes an organic gelling agent, which is a diblock copolymer that is present in an amount of about 5 to 20 percent by weight. However, no more than 1.5 percent by weight of inorganic gelling agents may be used without impairing the long-term stability of the viscosity and the yield stress of the filling material. Preferably, a blend of two different polyalphaolefin oils are used while inorganic gel ling agents are completely avoided. Critical-yield stress is kept appropriately low (i.e., less than 0.01 psi) by the use of diblock copolymers. Together, these factors cooperate to provide a filling material whose yield stress and viscosity have excellent stability over time.

Optical cable having a filling material with stable viscosity and yield

A cable 20 of this invention includes at least one core 22 comprising a plurality of coated optical fibers 25 and a filling material 26 which is disposed about the fibers 25. Typically, the fibers 25 and the filling material 26 are disposed within a tubular member 28 which is disposed within a sheath system 27. The sheath system 27 may include longitudinally extending strength members 30 in addition to a plastic jacket 32. The filling material made in accordance with the preferred embodiment of the present invention is one which comprises at least two different hydrocarbons as an oil constituent and/or two different fumed silicas as part of a thickening agent. The hydrocarbon(s) may be a synthetic oil such as polyalphaolefin, for example, or a mineral oil, or a combination of synthetic oils and/or mineral oils. The combination of oils is used to help low temperatures properties as well as better incorporate a gelling system which may include a copolymer. A copolymer is used mainly to reduce oil separation. Additionally, a combination of gelling agents such as mixtures of two different fumed silicas is used to build a more stable and desirable network structure in the filling material. The novel combination of oils and fumed silicas produces a filling material capable of passing EIA/TIA Standard FOTP-81, Compound Flow (Drip) Test for Filled Optical Cable, Section 8 up to 80.degree. C. and has a critical-yield stress of less than about 0.002 psi.

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Dunwoody, GA, United States of America

Jim Jenqtsong Sheu