Abstract: A system of aligning concatenated sections of multicore optical fiber incorporates the capability of intentionally changing core assignments as part of the azimuthal alignment process. The intentional changing of core assignments, referred to as offset clocking, compensates for differences in properties of the individual core regions in a way that reduces variations between the spatial channels supported in the transmission system. The offset clocking technique can be used, e.g., to improve the attenuation (or other selected properties of the propagating signals). The offset clocking technique may be used to step through sequential changes core assignments at one or more splice locations (passive clocking) or identify a particular pairing of cores from one fiber section to the next (e.g., “good quality” core assigned to a “poor quality” signal exiting the first section) and rotate the fiber sections with respect to each other to achieve this particular core assignment.

Abstract: Described herein are systems, methods, and articles of manufacture for high back-scattering waveguides (e.g., optical fibers) and sensors employing high back-scattering optical fibers. Briefly described, one embodiment comprises a high back-scattering fiber, or enhanced scattering fiber or “ESF,” that features resistance specifications that remain intact over lengths of fiber in excess of 1 m, or preferably >100 m, or preferably >1 km, wherein the reflectivity of the ESFs may be precisely tuned within a range from ?100 dB/mm to ?70 dB/mm, and wherein the enhanced scattering may be spatially continuous or, alternatively, may be at discrete locations spaced apart by 100 microns to >10 m.

Abstract: A multi-core optical fiber comprises at least two (2) helical cores. When the multi-core optical fiber is bent, such that it has a bend length (L) and a bend radius (R), each core experiences a different strain, thereby resulting in an effective optical length difference (?l) between the cores. In the present disclosure, the helical cores have a pitch (P) that reduces ?l/L to a value that is less than 5·10?6 (i.e., ?l/L<5·10?6).

Abstract: Described herein are systems, methods, and articles of manufacture for a coated fiber modified by actinic radiation to increase back-scattering, which experiences very little back-scattering decay at a temperature and time of exposure that is sufficient to noticeably degrade the coating and/or noticeably degrade the optical fiber due to outgassing of hydrogen from the coating. In one embodiment, an optical fiber comprises a fiber length, a coating having a treated coating weight, wherein the treated coating weight is at least 25% less of an original coating weight prior to an annealing treatment, and an optical back-scatter along the fiber length greater than a Rayleigh back-scattering over the fiber length, wherein the optical back-scatter does not decrease along the fiber length by more than 3 dB after exposure to annealing treatment.

Abstract: An extended length of optical fiber having an offset core with an inscribed Bragg grating is used a distributed sensor in combination with an optical frequency domain reflectometer (OFDR) to enable measurement small-scale (e.g., sub-millimeter) contortions and forces as applied to the fiber. The offset core may be disposed in a spiral configuration around the central axis of the optical fiber to improve the spatial resolution of the measurement. A reference surface exhibit a predetermined texture (in the form of a series of corrugations, for example, that may be periodic or aperiodic, as long as known a priori) is disposed adjacent to a longitudinal portion of the sensor fiber. The application of a force to the combination of the plate and the fiber creates a local strain in the grating formed along the offset core of the fiber that results in a shift in the Bragg wavelength of the grating.

Abstract: Embodiments of the invention include an optical fiber cable. The optical fiber cable includes a multi-fiber unit tube that is substantially circular and dimensioned to receive a plurality of optical fibers. The optical fiber cable also includes a plurality of partially bonded optical fiber ribbon units positioned within the multi-fiber tube. The partially bonded optical fiber ribbon units are partially bonded in such a way that each partially bonded optical fiber ribbon is formed in a substantially circular shape or a random shape. The optical fiber cable also includes at least one elastomeric strength layer formed around the partially bonded optical fiber ribbon units. The optical fiber cable also includes an outer jacket surrounding the multi-fiber tube.

Abstract: Drop lines are supported and routed from a an ADSS trunk cable to designated users. Each of a number of non-metallic elongated support members has a main passage, and a first slit for enabling the cable to be urged into the passage from outside. Each member also has a number of aligned outer passages, and associated second slits for enabling a drop line to be urged into a given outer passage from outside. A band may be applied about each support member to prevent the cable and the drop lines from escaping the member through the slits. One end of each drop line is connected to the cable fibers inside a closure fixed at one end of a cable span. A drop line exiting an outer passage in a given support member is routed either through an outer passage in a successive member, or away from the cable to a designated user.

Abstract: A system of aligning concatenated sections of multicore optical fiber incorporates the capability of intentionally changing core assignments as part of the azimuthal alignment process. The intentional changing of core assignments, referred to as offset clocking, compensates for differences in properties of the individual core regions in a way that reduces variations between the spatial channels supported in the transmission system. The offset clocking technique can be used, e.g., to improve the attenuation (or other selected properties of the propagating signals). The offset clocking technique may be used to step through sequential changes core assignments at one or more splice locations (passive clocking) or identify a particular pairing of cores from one fiber section to the next (e.g., “good quality” core assigned to a “poor quality” signal exiting the first section) and rotate the fiber sections with respect to each other to achieve this particular core assignment.

Abstract: An optical fiber cable comprises an inner tube with strength members that are located external to, and alongside of, the inner tube. Water-blocking material is also located external to the inner tube. A sheath surrounds the strength members and the water-blocking material. The cable further comprises an optical fiber with a core, a trench surrounding the core, a cladding surrounding the trench, and a coating applied over the cladding. The cable comprises a fiber arrangement with N optical fibers (with N being an integer (e.g., 16, 32, 48, 96, etc.), of which at least one optical fiber has: a maximum effective area (Aeff) of approximately seventy-five square micrometers (˜75 ?m2) at a wavelength (?) of approximately 1550 nanometers (˜1550 nm); a maximum mode field diameter (MFD) of ˜8.8 ?m at ? of ˜1550 nm; a maximum cable cut-off ? of ˜1520 nm; and, a maximum attenuation of ˜0.180 decibels-per-kilometer (dB/km) at ? of ˜1550 nm.

Abstract: An all-fiber supercontinuum (SC) optical source utilizes a combination of a seed pulse supply of short-duration optical pulses with a highly non-linear optical medium in the form of two or more concatenated sections of highly non-linear optical fiber (HNLF) of different dispersion values and lengths. The two or more sections of HNLF are configured to include at least one section that exhibits a positive dispersion value and one section that exhibits a negative dispersion value. Non-linear effects such as self-phase modulation (SPM), cross-phase modulation (XPM), Raman amplification, and the like, cause the seed pulses to broaden as they propagate through each section of HNLF, where the differences between the dispersion values, as well as the lengths of each fiber section, are particularly configured to create an SC output that is wide and smooth, exhibiting a stable intensity and high coherence level.

Abstract: A method of splicing multicore optical fibers to one another for use in a data network. First and second multicore optical fibers each have a number of cores arranged in a certain pattern about the fiber axis, thus defining a number of pairs of cores wherein the cores of each pair are arrayed symmetrically with respect to a key plane that includes the fiber axis. Ends of the first and the second fibers are arranged in axial alignment to one another such that the key plane at the end of the first fiber is aligned with the key plane at the end of the second fiber, thereby placing a defined pair of cores in the first fiber in position for splicing to a corresponding defined pair of cores in the second fiber. The defined pairs of cores in the two fibers are then spliced to one another.

Abstract: A system for sensing microbends and micro-deformations in three-dimensional space is based upon a distributed length optical fiber formed to include a group of offset cores disposed in a spiral configuration along the length of the fiber, each core including a fiber Bragg grating that exhibits the same Bragg wavelength. A micro-scale local deformation of the multicore fiber produces a local shift in the Bragg wavelength, where the use of multiple cores allows for a complete micro-scale modeling of the local deformation. Sequential probing of each core allows for optical frequency domain reflectometry (OFDR) allows for reconstruction of a given three-dimensional shape, delineating location and size of various microbends and micro-deformations.

Abstract: A high backscattering optical fiber comprising a perturbed segment in which the perturbed segment reflects a relative power such that the optical fiber has an effective index of neff, a numerical aperture of NA, a scatter of Rp?r(fiber) that varies axially along the optical fiber, a total transmission loss of ?fiber, an in-band range greater than one nanometer (1 nm), and a figure of merit (FOM) in the in-band range. The FOM being defined as: F ? O ? M = R p ? "\[Rule]" r ( fiber ) ? fiber ( NA 2 ? n eff ) 2 .

Abstract: An optical connector for terminating a cable containing one or more multicore fibers. The connector has a plug housing, a ferrule disposed inside the housing, a rotatable frame, and a multicore fiber (MCF) stub having a length of a first MCF a portion of which is fixed inside the ferrule so that a first endface of the fiber is exposed at the front end of the ferrule. An opposite endface of the first MCF is cleaved for fusion splicing to a second MCF in the cable to be terminated. The ferrule also has a flange, and the frame is formed to engage the flange for rotation so that cores in the first MCF can be aligned and positioned in a prescribed orientation relative to the plug housing, and cores in the second MCF can be aligned with corresponding cores in the first MCF when the first and the second MCFs are fusion spliced to one another.

Abstract: An amplified hollow-core fiber (HCF) optical transmission system for low latency communications. The optical transmission system comprises a low-latency amplified HCF cable. The low-latency amplified HCF cable comprises multiple HCF segments (or HCF spans). Between consecutive HCF segments, the system comprises low-latency remote optically pumped amplifiers (ROPAs). Each ROPA comprises a gain fiber, a wavelength division multiplexing (WDM) coupler, and an optical isolator. Preferably, the ROPAs are integrated into the HCF cable. Each ROPA is pumped by a remote optical pump source, which provides pump light to the gain fiber. The gain fiber receives an optical transmission signal from the HCF. The WDM coupler combines the pump light with the optical transmission signal, thereby allowing the gain fiber to amplify the optical transmission signal to an amplified transmission signal. The amplified signal is transmitted to another HCF segment through the optical isolator.

Abstract: Described herein are systems, methods, and articles of manufacture for a spatially nonuniform scattering profile along its length, whose backscattering signal can be used for sensing even after fiber attenuation increases due to the conditions in the sensing environment. In one embodiment, the fiber has been pre-exposed to the conditions that produce attenuation, and the spatially nonuniform profile compensates for this. Subsequent exposure then results in very little or at least acceptable levels of additional attenuation. An exemplary fiber comprises a fiber length and an optical back scatter along the fiber length greater than a Rayleigh back scattering over the fiber length, wherein the optical back scatter does not decrease along the fiber length by more than 3 dB after exposure to a hydrogen-rich first environment having a given pressure and temperature.

Abstract: Described herein are systems, methods, and articles of manufacture for reducing coupling loss between optical fibers, more particularly, to reducing coupling loss between a hollow-core optical fiber (HCF) and another fiber, such as solid core fibers (SCF), through the use of mismatched mode field diameter (MFD) and optical connector assemblies for low latency patchcords. According to one embodiment, an article is configured to reduce a coupling loss between multiple optical fibers, wherein the article includes an HCF supporting the propagation of a first mode and an SCF coupled to the HCF. According to a further embodiment, a method is described for reducing the coupling loss or splicing loss between optical fibers, such as an exemplary HCF and a solid core SMF.

Abstract: A high backscattering optical fiber comprising a perturbed segment in which the perturbed segment reflects a relative power such that the optical fiber has an effective index of neff, a numerical aperture of NA, a scatter of Rp?r(fiber) that varies axially along the optical fiber, a total transmission loss of ?fiber, an in-band range greater than one nanometer (1 nm), and a figure of merit (FOM) in the in-band range. The FOM being defined as: FOM = R p ? r ( fiber ) ? fiber ? ( NA 2 ? n eff ) 2 .

Abstract: In curing a matrix material of a rollable optical fiber ribbon, ultraviolet light may be concentrated in a selected range of wavelengths to avoid further curing the primary coating of each fiber. A ribbon may be made by aligning the fibers, each having at least a primary coating, into a ribbon shape, applying a matrix material in intermittently distributed portions along the ribbon-shaped group of fibers, and exposing the ribbon-shaped group of fibers and applied matrix material to ultraviolet light concentrated in a range of wavelengths absorbed more by the matrix material than by the primary coating.

Abstract: An optical fiber cable may include a cable jacket, a rigid tensile reinforcement member centered within the cable jacket, and a plurality of partially bonded optical fiber ribbons around the rigid tensile reinforcement member. The optical fiber cable does not include any buffer tubes but may include a cushioning layer adjacent the ribbons.