Abstract: An optical cable (10) includes one or more tubes (120), each containing a number of optical fibers (101), and a plastic jacket (160) that encloses the tube(s). A pair of diametrically opposed rods (300-1, 300-2) are at least partially embedded in the polyethylene jacket and are made from continuous-filament glass fibers that are embedded in epoxy. Each rod has a compressive stiffness that is effective to inhibit substantial contraction of the cable, and a tensile stiffness that is effective to receive tensile loads without substantial transfer of such loads to the glass fibers. Each dielectric rod includes a thin layer (330) of a frictional adhesion coating that provides a controlled adhesion between the rod and the jacket of between 50 and 300 lb./in2. Whereas dual-rod cable designs have a preferred bending plane that passes through the rods, controlled adhesion between the rods and the jacket enables the cable to be easily bent in other planes and to be blown through ducts having multiple corners.

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: An optical cable (10) includes one or more tubes (120), each containing a number of optical fibers (101), and a plastic jacket (160) that encloses the tube(s). A pair of diametrically opposed rods (300-1, 300-2) are at least partially embedded in the polyethylene jacket and are made from continuous-filament glass fibers that are embedded in epoxy. Each rod has a compressive stiffness that is effective to inhibit substantial contraction of the cable, and a tensile stiffness that is effective to receive tensile loads without substantial transfer of such loads to the glass fibers. Each dielectric rod includes a thin layer (330) of a frictional adhesion coating that provides a controlled adhesion between the rod and the jacket of between 50 and 300 lb./in2. Whereas dual-rod cable designs have a preferred bending plane that passes through the rods, controlled adhesion between the rods and the jacket enables the cable to be easily bent in other planes and to be blown through ducts having multiple corners.

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: 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: 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: 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 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.