Abstract: An optical fiber cable (20) includes a core (22) which includes a plurality of bundles (31, 31 ) of optical fiber (24) and a yarn-like strength member system (35) which is wrapped with an oscillated or unidirectional lay about the optical fibers. The strength member system also provides impact resistance for the fibers. A jacket (40) which may include a flame-resistant plastic material encloses the core with the outer diameter of the jacket being substantially less than that of typical optical fiber cables. Portions of the strength member system contact an inner surface of the jacket, an outer surface of which is the outer surface of the cable.

Abstract: In the manufacture of an article such as optical fiber which includes a light energy cured coating material, fiber (21) is drawn from a preform (22) and coating with one or preferably two layers (42,44) of light curable coating materials. Afterwards, the coating materials are cured. Increases in manufacturing line speed may be achieved if the cure speed of the coating materials is increased. This is accomplished by the simultaneous application of a magnetic field during irradiation of the curable coating materials to enhance the crosslinking of the coating materials by a free radical polymerization mechanism. Upon absorption of light, a photoinitiator in each composition cleaves to produce two free radical fragments in the spin paired or singlet state. The magnetic field has the effect of enhancing the production of spin parallel radicals which enhances the polymerization initiation of the coating material, thereby allowing an increase in the manufacturing line speed through drawing and coating apparatus.

Abstract: A low loss, tunable optical filter (20) comprises two ferrules (24-24) which are aligned axially with each of two adjacent end faces being provided with a wafer (30). A mirror (40) is embedded between each end face and its associated wafer, the wafer being bonded to the end face of its associated wafer. Optical fiber is disposed in a passageway which extends through each ferrule and through the associated wafer. The ferrules and associated wafers are supported to cause adjacent exposed faces of the wafers to be in predetermined spatial relation to each other. Any gap therebetween may be fixed or may be adjusted by a piezoelectric transducer system (44). The disclosed filter provides rejection ratios which are sufficiently high for frequency discrimination in frequency shift keying systems and for channel selection or switching in wave division multiplexer applications.

Abstract: An optical fiber package (52) includes a length of optical fiber (22) wound in a plurality of convolutions on a bobbin (50). In order to maintain the convolutions in a precision wound package and to prevent snags during payout, it is necessary that each convolution of optical fiber be adhered to at least a portion of an adjacent convolution. This is accomplished by providing the length of optical fiber with an adhesive material (32) which is not tacky at room temperature but which becomes tacky at a predetermined temperature. After the convolutions have been wound on the bobbin, the bobbin is treated to cause the adhesive material to become tacky and cause each convolution to adhere to at least a portion of adjacent convolutions. Suitable adhesion is caused to occur with any adhesive material for which molecular bonding can occur across the interface between contiguous portions of adjacent convolutions as a result of suitable treatment.

Abstract: An optical fiber (24), destined to receive a hermetic coating (32), is moved through a hermetic coating apparatus (30) wherein the fiber, entering the hermetic coating apparatus at a predetermined temperature, is caused to be engaged by a reactive gas. The reactive gas, reacting with the heated fiber, is effective to cause a layer of a hermetic material to be deposited adjacent to the outer surface of the fiber. A cross-flow purge gas is effective to prevent a resultant accumulation of a soot comprising reactive components of the reactive gas adjacent to portions of the hermetic coating apparatus which become heated by the fiber. Failure to prevent the accumulation of the soot may lead to fiber abrasions and reduced fiber strength.

Abstract: A steam-resistant optical fiber cable (20) includes a core (21) comprising a plurality of optical fiber ribbons (22,22) disposed within a tubular member (30) comprised of a high temperature resistant material. The tubular member is disposed within a hermetic sealing member (40) which comprises a metal of low electrochemical activity having a sealed seam. An outer jacket (50) is disposed about the hermetic sealing member and in a preferred embodiment is characterized by resistance to degradation in high temperature, high humidity environments. The core may be unfilled or filled with a waterblocking material and in a preferred embodiment, a waterblocking member is interposed between the tubular member and the hermetic sealing member.

Abstract: A package (20) of wound optical fiber (22) includes a spool (23) on which are wound a plurality of layers with each layer comprising a plurality of convolutions of the optical fiber. The winding is accomplished such that each successive convolution is spaced from a preceding convolution. The spacing is such that on the third and further outer layers, each optical fiber is tangent to each of two adjacent convolutions of a previously wound layer and to one convolution of the next inner layer. Also, each convolution in each layer after an innermost layer crosses transversely optical fiber of an immediately preceding layer in two relatively closely spaced locations and such that crossovers in successive layers are staggered circumferentially of a winding surface. Because of the nesting which is caused to occur, excellent density, package rigidity and stability are achieved.

Abstract: A connecting block (20) which includes a plurality of protectors (30,30) to protect a plurality of incoming communications lines includes a rear panel (28) which is stationary with respect to a housing (25) of the connector block. Mounted in cavities (62, 62) of the rear panel is a mass of contact elements (40,40) arranged in rows and columns and each having a rearwardly extending portion which is connected to a conductor which extend from an associated protector and an opposite portion which extends toward a front panel (60). Mounted in cavities (62,62) of the front panel is a mass of trifurcated contact elements (70,70) each having a base portion (72) and a conductor receiving portion. In a disconnected position, the opposite portion of each contact element is aligned with and overlaps a base (72) of an associated trifurcated contact element with a hook-like portion (46) being spaced from the base of the associated trifurcated contact element by a web (96) of dielectric material in each cavity.

Abstract: A closure (20) which may be used temporarily in the restoration of service to an optical fiber cable (50) which has been damaged includes a base (22) and a cover (24) which include mating longitudinal edge portions. The base and the cover are secured together with longitudinally extending C-clamps (97--97) which are moved slidably to engage the mating longitudinal edge portions of the base and the cover. Cables to be spliced enter the closure through openings in compliant end blocks (67--67). Modules (40,40) are disposed within the closure and hold connective devices used to make connective arrangements between optical fibers of the cables. The closure is easy to assembly is lightweight and may be reused.

Abstract: A modular plug (23) for terminating cordage includes a housing (41) having a free end (46) and a cordage-input end. An end portion of a length of cordage (21) to be terminated by the plug is inserted into the cordage-input end of the housing to cause exposed individually insulated conductors extending beyond a jacketed portion of the cordage to be received in a conductor-holding portion of the housing. Blade-like terminals (42--42) inserted into slots opening to an exterior surface of the housing engage electrically the conductors. An anchoring member (61) is caused to be moved to an operative position whereat a primary jacket anchoring surface (74) of the anchoring member becomes disposed in compressive engagement with a jacket of the cordage. The geometry of the anchoring member is such that the primary anchoring surface in an unoperated position is angled to a longitudinal axis of the end portion of the length of cordage.

Abstract: Methods and apparatus are provided for providing an electrically matched pair (20) of insulated metallic conductors (21,21). Insulation is applied to successive portions of a length of wire-like metallic conductor (22) after which a colorant material (37) is applied to the surface of a plastic insulation material of a first portion of the length of the metallic conductor which is being moved along a path of travel. Facilities are provided for shielding a supply of the colorant material from the moving insulated metalic conductor and for then exposing a second portion of the length of the insulated metallic conductor to a different colorant material. The insulation and the colorant materials and their disposition with respect to the insulation are such that the dielectric constant of one insulated metallic conductor of the pair is substantially equal to that of the other.

Abstract: An optical fiber closure (20) which is particularly suitable for connecting small fiber count cables and for repairs of same includes a longitudinally extending electrical bonding and support member (70) for supporting in-line connections between optical fibers of cable end portions which enter the closure from opposite ends thereof. Each cable end portion extends through a cable and clamping and sealing means (40) which is adapted to become secured to a tubular member (60) in which is disposed the support member and which is adapted to provide sealed engagement with the entering cable end portion to prevent the ingress of moisture.

Abstract: In order to restore quickly service which has been interrupted by damage in at least a portion of a cable, ends of optical fibers on one side of a damage location are spliced to optical fiber end portions of a restoration cable (70) within first and second closures (22,23) of a restoration kit (20). The first closure is attached to a foamed polymeric mounting pad attached to one flange of a deployment reel (100) mounted rotably on a payout spindle (135) which extends normally from one portion of a carrying case (21). Optical fibers of each end of the restoration cable are connected to splicing devices mounted in splicing modules (40,40) in the first and second closures. The second closure is moved from the case toward an opposite side of the damage location whereat fibers of the damaged cable on the other side of the damage location are extended into the second closure and spliced to the restoration cable therein.

Abstract: A coated optical fiber (30) includes optical glass fiber which has been drawn from a preform and provided with one or more layers of coating materials having defined properties. The layer (32) of coating material which is contiguous to the drawn glass fiber may be one which in a preferred embodiment is cationically cured coating material. Curing of the cationically cured coating material causes an acid to be generated. The acid which has a relatively long life is effective to reduce sufficientlythe pH of the environment in contact with the drawn glass to cause the coated optical fiber to have enhanced mechanical strength.

Abstract: An unshielded buried service wire (20) includes a core (22) and a jacket (40). The core comprises two pairs (24-24) of insulated metallic conductors (26-26). Also associated with each conductor pair is a longitudinally extending waterblocking member (33) which inhibits the flow of water longitudinally of the wire. The jacket has a transverse cross sectional configuration which is generally oval. Adjacent to each of opposed small radius of curvature portions of the service wire and embedded substantially in the jacket is a longitudinally extending, rod-like strength member (50) which is caused to adhere to plastic material of the jacket.

Abstract: Methods are provided to detect, classify and quantify defects such as chips, pits, scratches and cracks in a polished end surface (31) of optical fiber and specifically in an end face of an optical fiber terminated by a ferrule (34). Images of the end face are acquired at each of three focal positions which collectively include all the features of interest. Information from these images is combined into a single image which is processed further. Discrepancies between the images are used to discriminate between cracks and scratches. Morphological processing is used to segment the fiber from its ferrule and a Hough transform is used to estimate the center and radius of the optical fiber, which facilitates the isolation of the fiber. Chips and pits in the fiber end face are detected and quantified by thresholding and morphological processing of the isolated fiber. Edge detection is used to detect edge segments resulting from scratches and cracks. Then the line segments are classified into scratches and cracks.

Abstract: A preform tube (31) is caused to be collpased into a preform rod by causing a heat zone (54) provided by a torch assembly (50) to traverse the tube longitudinally in a plurality of passes. During this so-called collapse mode, a muffle tube (100) encloses that portion of the tube which extends through the torch assembly. Advantageously, the muffle tube projects a predetermined distance beyond one major face of the torch assembly. The torch assembly comprises annular semi-circular end plates and as annular semi-circular center portion having a plurality of exit ports through which gases are directed into engagement with the tube. The center portion is caused to be recessed between the end plates thereby causing the heat zone generated by the gases to be narrowed.

Abstract: A communications cable (20) in which plastic material which is disposed about each transmission medium thereof is characterized by a relatively low dielectric constant. The cable exhibits relatively low flame spread and low smoke generation while maintaining circuit integrity through a fire retardant composition which includes a mixture of an organic resin and first and second inorganic oxide constituents. The first inorganic oxide constituent is characterized by a melting point in the range of about 350.degree. C. The second inorganic oxide constituent comprises a higher melting devitrifying frit which begins to crystallize at about 650.degree. C. Advantageously, when the cable is exposed to high temperatures, the mixture of the first and second inorganic oxide constituents melts and forms a crusty layer which is interposed between the covering plastic material and other components of the cable.

Abstract: A glass tube (31) from which optical fiber is to be drawn is heated by a torch assembly comprising a plurality of nozzles (54--54) disposed on a carriage. In order to avoid contamination of the tube by particles of the torch assembly resulting from thermal degradation,the nozzles are disposed in a plane which is normal to an axis (36) of the tube with each nozzle axis inclined so that flame fronts associated with the nozzles are substantially closer to the tube than to the torch assembly. Reaction of materials which are flowed into the tube is enhanced by including a second row of nozzles (91--91) which are inclined within a plane which is inclined to the longitudinal axis of the tube. In order to collapse the tube into a rod, a muffle member (100) preferably is caused to be disposed about the tube with an opening in the periphery of the muffle member to allow portions of the gas flows to converge and to allow heat energy to be transferred from the flame fronts to the tube.

Abstract: A protected package (20) of optical fiber includes a spool which includes a hub (22) and two spaced flanges (24,26). Optical fiber (23) is wound on the hub with an end of the fiber being accessible to allow the fiber to be tested. A strip (52) of plastic material is wrapped about the spool with longitudinal edge portions (54,54) of the strip overhanging the flanges to provide a cover (50). The protected package permits withdrawal of the fiber through a gap (64) between the cover and the flanges. Further, in a preferred embodiment, each longitudinal edge portion is provided with openings (60,60). The openings are spaced apart such that when a strip is wrapped about any of expected size spools, at least one pair of the openings will become aligned to allow insertion of fastening means (62) which function to hold the strip assembled to the spool to protect the fiber and to prevent unintended removal of the cover.