Abstract: An optical fiber cable (20) includes a core (22) comprising at least one optical fiber (23) which is enclosed in a tubular member (28) and which includes a non-metallic sheath system (30). The sheath system includes two contiguous layers (40, 50) of non-metallic strength members which extend longitudinally along the cable and which are wrapped helically in opposite directions about the tubular member. The layers of strength members are enclosed in a plastic jacket (36). At least some of the strength members which are capable of withstanding expected compressive as well as tensile loading are coupled sufficiently to the jacket to provide a composite arrangement which is effective to inhibit contraction. Those strength members cooperate with the remaining strength members to provide the cable with a predetermined tensile stiffness and to cause the cable to be relatively flexible.

Abstract: An extrusion apparatus for providing a plastic jacket (32) about an advang cable core (23) which has been wrapped with a laminated metallic foil (76) includes dual core tubes. An inner one (86) of the core tubes extends into an extrusion chamber and has a free end portion (89) spaced from and disposed concentrically within an end portion (94) of an outer core tube (93). The foil, which is relatively cool and which functions as a shield (26), engages an inner wall of the inner core tube. This causes an overlapped longitudinal seam (78) of the shield to be maintained during the passage of the shielded cable core through the inner core tube. As a result, molten plastic material which is to form the jacket (32) is isolated thermally from the relatively cool shield and is prevented from being cooled prematurely prior to its being tubed about the advancing cable core.

Abstract: An alignment sleeve (66) for holding two conically shaped portions (30-30) of plugs (24-24) each of which terminates an optical fiber (25) includes two conically shaped cavities (68, 70) communicating through a common minimal diameter plane (72). After the sleeve has been molded, a tool (100) faced with an abrasive material is inserted into each cavity of the sleeve and turned rotatably while a force is applied in a direction parallel to the longitudinal axis of the tool. This causes material to be removed from the walls defining the cavities so that when the two plugs are inserted into the cavities, the axes of the fibers will be aligned coaxially and the end faces of the fibers will have a predetermined separation. The methods of this invention also may be used to adjust a length measurement of plugs. This is accomplished by inserting a plug into a conically shaped cavity of a tool.

Abstract: In order to connect two optical fibers (26-26), each of two plugs (40-40) each having a passageway (41) in which is received an optical fiber is mounted in a connector body (42). Each optical fiber comprises a core (25) and a cladding (27). The plugs are destined to be received in a sleeve (75) of a coupler (60) such that their longitudinal axes are coaxial. Alignment of the fiber cores, at least radially of the longitudinal axes, is accomplished by locating for each plug the intersection of a radial line which extends through the centroid of the optical fiber core with the periphery of the plug. An orienting pin is mounted in each connector body in intentional radial alignment with the intersection. The connector bodies are inserted into opposite ends of the coupler sleeve to cause each pin of each connector body to be received in a slot in the coupler.

Abstract: In order to connect two optical fibers (26--26), each of two plugs (40--40) each having a passageway (41) in which is received an optical fiber are mounted in a connector body (42). The plugs are destined to be received in a sleeve (75) of a coupler (60) such that their longitudinal axes are coaxial. Alignment of the passageways, at least radially of the longitudinal axes, is accomplished by locating for each plug the intersection of a radial line which extends through the centroid of an opening of the passageway with the periphery of the plug. Each plug is mounted in its connector body such that the intersection is aligned radially with a pin extending from the connector body. The connector bodies are inserted into opposite ends of the coupler sleeve to cause each pin of each connector body to be received in a slot in the coupler.

Abstract: A biconic connector includes two plugs (44--44) each of which terminates a single fiber optical cable (55) and each of which includes a conically shaped end portion (50). The connector also includes an alignment sleeve having back-to-back conically shaped cavities each of which is adapted to receive an end portion of a plug. In order to minimize loss through a connection, it becomes important for the axis of the end portion of the core of the optical fiber in the conically shaped end portion of the plug to be coincident with the axis of revolution of the conically shaped end portion. This is accomplished by holding the plug in a fixture such that its conically shaped end portion is exposed and the fixture adapted to be turned about an axis of rotation. Images of light launched into the optical fiber are acquired in two planes at a plurality of positions spaced apart along a reference axis.

Abstract: In an apparatus (20) for end finishing an assembly (22) comprising a plurality of lightguide fibers (23--23) positioned between two silicon chips (26--26), a tool carriage (45) is moved past the assembly which at first is held in a fixed position with respect to a path of travel of the carriage. A profiling wheel (110) which is mounted rotatably on the carriage severs a portion of the chips and fibers from the assembly to provide an end portion having a predetermined end configuration. Subsequently, a grinding wheel (131) and a polishing wheel (141) are moved past the newly formed end of the assembly to grind and polish a surface of the end portion and ends of the fibers which terminate in the surface. These last two operations are accomplished while forces are applied to the assembly to bias it toward the tool carriage to provide a controlled pressure and avoid the removal of excess material from the surface and fibers.

Abstract: A parallel data transmission system (20) comprises a cable (40) which is capable of balanced mode transmission but which is driven in an unbalanced mode. The cable includes a plurality of twisted pairs of individually insulated conductors (42--42) enclosed by a metallic shield (54). The twist lengths are relatively short to cause the pairs to be decoupled sufficiently from one another to allow substantially error-free, parallel transmission over relatively long distances. Interposed between the core and the shield is a spacing member (52) which has a relatively low dielectric constant. Receiving facilities are provided for detecting whether the level of transmitted signals is above or below predetermined threshold values and for converting the received signals into one of two or more logic levels. Advantageously, this system increases substantially the distances over which substantially error-free transmission in an unbalanced mode can be accomplished.

Abstract: A cable closure includes two spaced end plugs (110-110) through which cable nd portions extend and two cover portions (60-60) which are mated together along tongue and groove portions and held together by C-shaped clamps that engage the tongue and groove portions. Conductors of the cables are spliced together and enclosed in a membranous container (40) which subsequently is caused to be filled with an encapsulant. The cover portions, which in a preferred embodiment are identical, include internally disposed plates each having spaced end strap portions which secure the cable end portions extending through the end plugs into the closure at locations external to the membranous container and prevent unintended lateral, longitudinal and torsional movement of the splice work relative to the encapsulant.