Abstract: An optical fiber cable includes a first jacket, typically comprising a polyvinyl chloride material, a core member comprising at least one, typically .ltoreq.10, optical fiber(s), and a core wrap loosely surrounding the optical fiber(s). The optical fiber(s) typically is (are) slightly overstuffed. The cable further comprises three non-metallic strength members (or groups of strength members) completely embedded in the first jacket and coupled thereto. In cables containing three strength members, the coupling is typically characterized by a pull-out strength of at least 25, preferably more than 40, lbs/in of strength member. Each strength member comprises a multiplicity of impregnated filaments, preferably borosilicate glass filaments impregnated with a urethane. The preferred cable typically has a circularly symmetric cross section, with the three strength members, each of radius r.sub.s, disposed longitudinally, their axes a distance R from the axis of the first jacket, with R>1.155(r+r.sub.

Abstract: Described is a method for producing metal silicide/silicon heterostructures. The method comprises depositing a very thin Si "template" layer on a relatively cold (<200.degree. C.) silicide substrate, raising the substrate temperature into the approximate range 500.degree.-800.degree. C. and maintaining it there while depositing further Si onto the template. The resulting Si layer can be of high crystalline perfection. The silicide advantageously is CoSi.sub.2, Co.sub.x Ni.sub.1-x Si.sub.2, CoSi.sub.y Ge.sub.2-y, or NiSi.sub.2, with 0<x<1,1<y<2.

Abstract: Incorporation of fluorine into a porous silica body, such as an unsintered body produced by a sol-gel method, by VAD or OVPO, reduces or eliminates bubble or pore formation upon re-heating of the glass formed by sintering of the porous material. Effective fluorine concentrations are between 0.01 and 5% by weight. The invention can be used advantageously in producing preforms and optical fiber.

Abstract: A grease composition comprising oil, colloidal particle filler, and, optionally, a bleed inhibitor is disclosed. The grease typically has a critical yield stress below 140 Pa at 20.degree. C., preferably below 70 or 35 Pa. The grease can advantageously be used as a cable filling material, especially for optical fiber cable. In the latter case it can result in cable having substantially no cabling loss. Preferred compositions comprise 77 to 95% b.w. of ASTM type 103, 104A, or 104B paraffinic or naphthenic oil, or polybutene oil; 2 to 15% b.w. of hydrophobic or hydrophilic fused silica; and optionally, up to 15% b.w. of styrene-rubber or styrene-rubber-styrene block copolymer, or semiliquid rubber.

Abstract: An optical fiber communications system with Raman amplification of the signal radiation comprises a broadband pump radiation source, or, preferably a multiplicity of pump radiation sources. The sources are selected to result in a pump radiation spectrum such that pump radiation intensity in the fiber core is less than a critical intensity I.sub.c. In particular, the average intensity of pump radiation in a first spectral interval, centered on any wavelength .lambda..sub.p in the pump radiation spectrum and of width equal to the Brillouin line width of the fiber at .lambda..sub.p, is to be less than that average intensity in the first spectral interval that results in conversion of 10% of the radiation in the first spectral interval to stimulated Brillouin radiation. Use of a multiplicity of pump sources not only can reduce pump noise and pump depletion due to stimulated Brillouin scattering, but typically also can result in enhanced system reliability and lower cost.

Abstract: Disclosed is BeF.sub.2 -based optical fiber. Such fiber can have, in addition to low loss, other advantageous properties. For instance, BeF.sub.2 -based dispersion shifted single mode fiber can have lower core-cladding index difference and larger core diameter than the corresponding SiO.sub.2 -based fiber, and BeF.sub.2 -based graded index multimode fiber can have larger bandwidth than the corresponding SiO.sub.2 -based fiber. The inventive fibers have a core and a cladding containing at least 30 mol % BeF.sub.2, and may contain up to 40 mol % of AlF.sub.3, and one or more members of the group consisting of NaF, KF, MgF.sub.2, CaF.sub.2, PbF.sub.2, PF.sub.5, and SiF.sub.4. An exemplary and currently preferred glass has nominal composition (in mol percent) 30KF-(15-x)CaF.sub.2 -xPbF.sub.2 -10AlF.sub.3 -45BeF.sub.2, with x.ltoreq.15. Single mode fibers according to the invention have minimum total dispersion in the range 1.5-2.0 .mu.m, and typically have 0.25%.ltoreq..DELTA..sub.esi .ltoreq.0.6%, and 2.5 .mu.m.

Abstract: The propagation speed of optical solitons in single mode optical fiber depends on the wavelength of the solitons. Thus, if solitons of different wavelengths are co-propagating, "collisions" between pulses can be expected to result. It has been found that collisions between solitons do preserve the soliton character of the colliding pulses, even in the presence of perturbations of the type present in fiber communications systems, e.g., core size variations, distributed or lumped loss, and distributed gain. Thus, a wavelength division multiplexed soliton system is possible, and techniques and formulae for the design of such systems are disclosed. In preferred embodiments, fiber loss is periodically compensated by Raman gain. Typical amplification periods (using currently available silica-based fiber) are 30-50 km, typical pump powers are less than 100 mV, and rate-length products of the order of 3.multidot.10.sup.5 GHz km are possible.

Abstract: Single mode and multimode silica-based optical fibers having a down-doped outer cladding are disclosed. The outer cladding material is derived from a preexisting silica tube that comprises an amount of index-lowering dopant, typically F or B, sufficient to result in an effective refractive index of the material that is at least about 0.001, preferably at least 0.0025, lower than the refractive index of SiO.sub.2. Single mode optical fiber according to the invention typically requires a smaller amount of deposited cladding material than an equivalent prior art fiber, and thus can be produced more economically. Multimode optical fiber according to the invention may have lower core doping or higher NA than equivalent prior art fiber. Down-doped substrate or sleeve tubes advantageously are produced by a gel process.

Abstract: In a plug-type optical fiber connector low loss can be achieved, without any active alignment of the fiber cores, if the two cylindrical plugs used in the connector are "contiguous" plugs, i.e., derived from contiguous segments of the tubular stock from which the plugs are produced, and if the plugs are arranged such that the "contiguous" ends of the plugs are the mating ends, and such that the rotational relationship between the plugs is substantially the one that existed prior to sectioning. The inventive connector comprises two contiguous plugs and includes features that permit identification of the contiguous ends and of the rotational relationship. In a preferred embodiment, the tubular stock is drawn glass stock, the two contiguous segments are left joined but scored circumferentially to permit easy separation in the field, with a longitudinal groove in the outer cylinder surface of the contiguous segments identifying the original rotational relationship.

Abstract: A solderless in-line connector has a U-shaped slotted contact member, with the slots extending the length of the respective upright portion of the member and into the base portion. This contact member geometry results, upon insertion of a wire into the slot, in elastic torsional as well as bending deformation of the contact member, which in turn permits accommodation of a wide range of wire sizes in a low profile connector. Further desirable features of the connector are the possibility of installation without use of special tools, and the possibility of sequential contact formation. The connector can advantageously be used for splicing small pair count cables, but it can also be adapted for making half taps.

Abstract: Silica-based optical fiber comprising at least a core and a cladding surrounding the core, both core and cladding material produced by a vapor phase deposition process. The core and/or the cladding comprise at least two substituents, one chosen from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, and the 4f-type rare earths (the "modifiers"), and the other chosen from B, Al, Ga, In, P, As, and Sb (the "homogenizers"). The maximum concentration of the substituents in the fiber is such that 3<(n.sub.1 M+n.sub.2 H)/H<20, preferably<10, where n.sub.1 and n.sub.2 are the valences of the modifier and the homogenizer, respectively, and M and H are the concentration, in mole %, of modifier and homogenizer, respectively. Fiber according to the invention comprises at least 50, frequently more than 80% by weight, SiO.sub.2, and further has a maximum modifier concentration of at least 0.2 mole %, preferably at least 1 mole %.

Abstract: An optical fiber connector of the continuous groove type comprising a substrate with a multiplicity of fiber-receiving grooves thereon, and a cover member comprising compliant fiber-contacting material having a modulus of elasticity less than about 10.sup.6 psi (less than about 6.9 GPa), preferably less than 10.sup.5 psi. Connectors according to the invention can have low loss, and low added loss during thermal cycling. In a particular preferred embodiment, the substrate is a molded plastic part, and the compliant material is an adhesive-backed polyester film.

Abstract: Disclosed is an electric field-assisted method for bonding one glass (or other inorganic insulator) body, typically a plate, to a similar body, such that the two bodies are spaced apart. The interior volume of such a composite body is advantageously filled with liquid crystal material, to produce a liguid crystal display cell. The method comprises forming a patterned layer of an appropriate bonding material (e.g., Al, Ge, Si, preferably Si) on a major surface of one of the two insulator bodies, placing a major surface of the second insulator body into contact with the bonding material, heating at least the second body to a bonding temperature (typically in the range 250.degree.-600.degree. C.), and applying a voltage (e.g., 500-1500 volt DC, the second body negative) across the thus formed sandwich.

Abstract: A single mode optical fiber comprises a core, a first cladding surrounding the core, and a second cladding surrounding the first cladding. It also comprises a third cladding region (or index "ring"). The core, has radius a and refractive index n.sub.c, the first, second, and third cladding regions have inner radii, R.sub.1i, R.sub.2i, and R.sub.3i, outer radii R.sub.1o, R.sub.2o, and R.sub.3o, and indices n.sub.1, n.sub.2, n.sub.3, respectively. The fiber has n.sub.1 <n.sub.3, R.sub.1o .ltoreq.R.sub.3i, R.sub.3o .ltoreq.R.sub.2i. In preferred embodiments, a=R.sub.1i, R.sub.1o =R.sub.3i, R.sub.3o =R.sub.2i. Appropriate choice of ring parameters can result in a lowering of the cut-off wavelength of the fiber, or in fiber that is less sensitive to macrobending than similar prior art fiber lacking an index ring, without substantial change in fiber parameters that depend primarily on the waveform in the core. An optical fiber communications system comprising the inventive fiber is also disclosed.

Abstract: An optical fiber connector comprising a fiber terminus piece with a longitudinal bore through which a bare fiber is inserted. The fiber terminus piece with an appropriately prepared fiber therein is held coaxially aligned with a mating terminus piece. The fiber terminus piece comprises, on its mating face, a "pedestal," typically having truncated-cone shape, extending outwardly from the plane of the face, with the fiber terminating within the face of the pedestal, whereby the area of potential contact between the mating terminus pieces is substantially reduced. The pedestal material advantageously is somewhat compliant, of compressive modulus between about 10.sup.4 and 10.sup.6 psi at 25.degree. C., preferably between about 10.sup.5 and 5.10.sup.5 psi. The novel geometry results in improved performance, as compared to prior art connectors having flat mating faces. Disclosed are also connectors comprising advantageous means for transferring axial loads from a cable strength member to the connector body.

Abstract: Pulses of electromagnetic radiation having predetermined spacing between pulses can be generated by coupling amplitude modulated carrier radiation into an appropriate nonlinear transmission medium that has anomalous dispersion in some spectral region. The amplitude modulation is to be such that the amplitude has peaks with the predetermined spacing, and the carrier wavelength is to be in the anomalous dispersion region of the medium. Interaction between the medium and the radiation then results in contraction of the width of the amplitude peaks, which can result in formation of narrow pulses. A preferred transmission medium is monomode fiberguide, e.g., silica-based single mode optical fiber. In addition to the method for producing a sequence of pulses, a communication system using the inventive method is disclosed. Furthermore, a communication system comprising Raman amplification of the signal is disclosed.

Abstract: The invention provides a method for making an optical fiber with a uniformly thin section of cladding. A preform having a core and at least one cladding layer is first made. The preform is prepared by cutting the preform so that the core is close to the surface of the preform. An optical fiber is pulled from the cut preform so the core is close to the surface of the optical fiber. The fiber may have cladding further removed by etching. A material selective etch may be used to make a protruding core fiber. Etching may be done on the preform before pulling the fiber.

Abstract: Optical fiber splicing method and apparatus. The method comprises aligning the ends of the fibers to be spliced by a procedure comprising coupling radiation into one of the fibers, the transmitting fiber, stripping nonfundamental mode radiation from the other fiber, the receiving fiber, and detecting the stripped radiation in such a manner that a substantial fraction of the detected radiation is lowest order nonfundamental mode (LP.sub.11) radiation for at least some relative position of the fiber ends. By adjusting the relative position of the fiber ends to minimize the detected power, the fibers are aligned. The procedure not only permits accurate alignment but can also be used to determine the splice loss. Apparatus for the practice of the method is also disclosed.

Abstract: An optical fiber communication system wherein predisposed emission means cause enhanced emission, at intermediate points along the fiber, of radiation propagating longitudinally through the fiber. Emission means according to this invention are incorporated into the fiber during fiber manufacture, and can be activatable or nonactivatable. Activatable means are preferred and comprise an effective concentration of an activatable chemical species, i.e., a species which can be activated by exposure to activating means, e.g., electromagnetic radiation, electrons, ions, or heat, activation typically resulting in a change of a fiber property, e.g, the refractive index, in a fiber region. Nonactivatable means comprise localized variations in one or more fiber parameters, spaced along the fiber. The enhanced emission can be detected and processed by conventional means.

Abstract: Optical fibers doped with nonglass forming refractory oxides, such as alumina and zirconia, are disclosed. Devitrification is retarded by adding an additional glass forming component, such as P.sub.2 O.sub.5, and by rapidly quenching the heated glass. Aluminum and zirconium-containing precursor vapors are formed by passing halide gas over heated aluminum or zirconium wire.