Abstract: Systems, devices, and techniques for performing wavelength division multiplexing or demultiplexing using one or more metamaterials in an optical communications systems are described. An optical device may be configured to shift one or more phase profiles of an optical signal using one or more stages of metamaterials to multiplex or demultiplex wavelengths of optical signals. The optical device may be an example of a stacked design with two or more stages of metamaterials stacked on top of one another. The optical device may be an example of a folded design that reflects optical signals between different stages of metamaterials.

Abstract: An anti-resonant hollow core optical fiber including: (A) a fiber longitudinal axis extending from a first end to a second end; (B) a cladding tube through which the fiber longitudinal axis extends, the cladding tube (1) extending longitudinally from the first end to the second end, (2) disposed azimuthally around the fiber longitudinal axis, and (3) including (a) a cladding outer surface at a cladding outer radius from the fiber longitudinal axis and (b) a cladding inner surface comprising at least one recess; and (C) at least one anti-resonant element in contact with the cladding inner surface, the at least one anti-resonant element extending longitudinally from the first end to the second end. The cladding inner surface is disposed at a cladding inner radius that has azimuthal variability (e.g., is not constant entirely) around the fiber longitudinal axis to define the at least one recess.

Abstract: The present disclosure is directed to various embodiments of methods for making an optical fiber. The methods may include drawing an optical fiber from a hollow-core preform. The hollow-core preform may include an annular support structure with an inner surface defining an interior cavity. The interior cavity may include a tube in direct contact with the inner surface of the annular support structure. The tube may include a wall defining an internal opening, the internal opening having a sealed end. The drawing may include regulating a pressure of the internal cavity to a predetermined pressure.

Abstract: Optical fiber draw production systems, pressure devices, and methods of fabrication of optical fiber are disclosed. In one embodiment, a method of forming an optical fiber includes heating a preform to draw the optical fiber through a draw furnace, and passing the optical fiber through a pressure device while the optical fiber is still forming, wherein a pressure within the pressure device is greater than an atmospheric pressure.

Abstract: A method of processing an optical fiber that includes drawing an optical fiber along a fiber pathway through a hollow light pipe, wherein the hollow light pipe comprises a first end having an opening with a radius Rp, a second end and a pipe body comprising a chamber extending from the first to the second end, the fiber pathway extending through the pipe body, and a reflective coating is disposed on the pipe body, and directing a light from a directed light source into the hollow light pipe through the opening such that the light is reflected by the reflective coating while propagating in the hollow light pipe, the optical fiber absorbing the light reflected by the reflective coating, wherein the light enters the opening of the hollow light pipe at an input angle in a range of from 10° to 70° with respect to the fiber pathway.

Abstract: A multicore optical fiber is provided including a first core region having a first refractive index profile, a second core region having a second refractive index profile, wherein the first core region is separated from the second core region by a separation distance in a range of 20-50 ?m, and an outer cladding surrounding the first and second core regions, wherein the first core region exhibits a first effective index and a first group index and the second core region exhibits a second effective index and a second group index, and the first and second effective indices are substantially different to suppress crosstalk and the first and second group indices are substantially the same to achieve a substantially similar group velocity.

Abstract: A method of categorizing a group of multimode optical fibers, the method including comparing an effective modal bandwidth of a first multimode optical fiber with a first threshold, the first multimode optical fiber being in a group of multimode optical fibers meeting a first OM-standard and the first threshold being an effective modal bandwidth of the first multimode optical fiber. The method further including categorizing the first multimode optical fiber as meeting OM functional requirements of a second OM-standard if the effective modal bandwidth of the first multimode optical fiber is equal to or above the first threshold, wherein the second OM-standard is higher than the first OM-standard.

Abstract: A method for producing a hollow-core preform may include rolling a glass sheet to form a rolled-glass structure; and attaching one or more of the rolled-glass structures to an inner surface of an annular support structure to form a hollow-core preform, wherein the inner surface of the annular support structure defines an interior cavity and the one or more of the rolled-glass structures are positioned within the interior cavity. The hollow-core preform may be drawn into a hollow-core optical fiber.

Abstract: A hollow-core optical fiber may include a hollow core extending along a central longitudinal axis of the fiber; a substrate, the substrate having a tubular shape and an inner surface surrounding the central longitudinal axis of the fiber; and a plurality of cladding elements positioned between the hollow core and the substrate, each of the cladding elements extending in a direction parallel to the central longitudinal axis of the fiber. Each of the cladding elements includes a primary capillary, the primary capillary directly contacting the inner surface of the substrate and having an inner surface defining a cavity, and a plurality of nested capillaries positioned within the cavity, each of the nested capillaries directly contacting the inner surface of the primary capillary.

Abstract: A single mode optical fiber is provided that includes a core region having an outer radius r1 and a maximum relative refractive index ?1max. The single mode optical fiber further includes a cladding region surrounding the core region, the cladding region includes a depressed-index cladding region, a relative refractive index ?3 of the depressed-index cladding region increasing with increased radial position. The single mode optical fiber has a bend loss at 1550 nm for a 15 mm diameter mandrel of less than about 0.75 dB/turn, a bend loss at 1550 nm for a 20 mm diameter mandrel of less than about 0.2 dB/turn, and a bend loss at 1550 nm for a 30 mm diameter mandrel of less than 0.005 dB/turn. Additionally, the single mode optical fiber has a mode field diameter of 9.0 microns or greater at 1310 nm wavelength.

Abstract: In one embodiment, an optical fiber includes an inner core having a core refractive index delta and profile shape parameter ? in the range of 1.8 to 2.6, including endpoints, and a cladding layer surrounding the inner core. The cladding layer includes an inner cladding segment having an inner refractive index delta, a trench segment having a trench refractive index delta, and an outer cladding segment having an outer refractive index delta. The optical fiber further includes a coating layer surrounding the cladding layer and having a thickness of less than 30 ?m and a modulus greater than or equal to 0.5 GPa.

Abstract: An anti-resonant hollow core optical fiber including: (a) a cladding tube including a cladding inner surface at a cladding inner radius from a fiber longitudinal axis, the cladding inner radius varying azimuthally around the fiber longitudinal axis, the cladding inner surface defining recesses, and each of the recesses merging with adjacent recesses so that the cladding inner surface forms peaks pointing inward toward the fiber longitudinal axis; (b) a plurality of primary capillaries, each of the plurality of primary capillaries (i) disposed within a different one of the recesses and contacting the cladding inner surface and (ii) contacting or merging with an adjacent primary capillary in both azimuthal directions around the fiber longitudinal axis; and (c) an effective core region tangential to the plurality of primary capillaries at a core radius from the fiber longitudinal axis, the plurality of primary capillaries disposed radially outward of the effective core region.

Abstract: A method of manufacturing a hollow core optical fiber including (a) a consolidated tube presenting step including presenting a consolidated cladding tube including a consolidated cladding first end, a consolidated cladding second end, a consolidated cladding longitudinal axis, and a consolidated cladding inner surface, the consolidated cladding inner surface defining a consolidated cladding interior and including consolidated cladding recesses (i) positioned around the consolidated cladding longitudinal axis and (ii) extending from the consolidated first end to the consolidated second end; and (b) a capillary tube coupling step comprising coupling preform capillary tubes to the consolidated cladding inner surface within the consolidated cladding recesses thus creating an optical fiber preform, each of the preform capillary tubes disposed within a different one of the consolidated cladding recesses.

Abstract: A system and method for coupling hollow-core optical fibers. The system operatively couples one hollow-core optical fiber to another hollow-core optical fiber using a length of tube fiber. The end face of each hollow-core optical fiber is operatively coupled to a respective end face of the tube fiber, e.g., by fusion splicing or another suitable means of connecting optical fibers. In operation, light propagating through one of the hollow-core optical fibers is transmitted into an end face of the tube fiber, propagates through the tube fiber, and is emitted from the other end face of the tube fiber and into the other hollow-core optical fiber.

Abstract: A hollow-core optical fiber that includes an outer cladding having a tubular shape with a hollow interior, a plurality of inner cladding members positioned with the hollow interior and a hollow core formed by the plurality of inner cladding members. The hollow-core optical fiber is configured to provide single-mode propagation of an optical signal within a wavelength range from 800 nm to 2000 nm.

Abstract: An optical fiber may include a glass fiber having a core region and a cladding region surrounding the core region. The optical fiber may further include a hybrid coating surrounding the cladding region. The hybrid coating may include a polymer coating and a metal coating. The polymer coating may include a primary coating and a secondary coating surrounding the primary coating, and a Young's modulus of the secondary coating may be greater than the Young's modulus of the primary coating. The optical fiber with the hybrid coating may demonstrate robust mechanical and optical performance while achieving increased fiber density for high bandwidth applications.

Abstract: An optical communication system can include a multiplexer/demultiplexer. The multiplexer/demultiplexer can transfer a first optical data signal between a first single-mode fiber and a first propagation mode of a few-mode fiber. The first propagation mode can have a first effective refractive index. The multiplexer/demultiplexer can transfer a second optical data signal between a second single-mode fiber and a combination of a second propagation mode of the few-mode fiber and a third propagation mode of the few-mode fiber. The second propagation mode and the third propagation mode can have a same effective refractive index that differs from the first effective refractive index. During propagation within the few-mode fiber, the second optical data signal can couple bidirectionally between the second propagation mode and the third propagation mode, while being substantially isolated from the first optical data signal in the first propagation mode.

Abstract: In embodiments, a mode selective optical fiber coupler may include a first propagation waveguide and a second propagation waveguide joined along a coupling length L. The first propagation waveguide and the second propagation waveguide may be tapered from an input face and an output face of the coupler to a midpoint of the coupler. An LP01 mode of an optical signal with a wavelength of 800-950 nm coupled into the first propagation waveguide propagates through the first propagation waveguide and is emitted from the first propagation waveguide. An LP01 loss of the coupler at the output face is less than 1.0 dB. An LP11 mode of the optical signal coupled into the first propagation waveguide is cross-coupled to the second propagation waveguide and is emitted from the second propagation waveguide. An LP11 loss of the coupler at the output face is less than 1.5 dB.

Abstract: Disclosed herein is a fiber optic system including at least one fiber optic cable assembly having a multimode optical fiber for communication of an optical data signal at an operating wavelength and a devices having a single-mode fiber stub with a mode field diameter within 20% of the mode field diameter of the fundamental mode of the multimode optical fiber at the operating wavelength. The single-mode fiber stub is secured to a ferrule, and a center of a core of the single-mode fiber stub is within 0.5 ?m of a center of the ferrule. An end of the single-mode fiber stub that extends to or beyond the back end of the ferrule and forms an optical connection with the multimode optical fiber where the center of the single-mode fiber stub is within 2 ?m of a center of the multimode optical fiber.

Abstract: An anti-resonant hollow core optical fiber including: (1) a fiber longitudinal axis; (2) a cladding tube; (3) a support ring disposed within the cladding tube comprising (i) an outer surface separated from the cladding tube by an outer space and (ii) an inner surface forming an inner space; (4) outer capillaries within the outer space (a) fused to the cladding tube and the support ring and comprising; (5) inner capillaries within the inner space fused to the support ring; and (6) an effective core region comprising a core radius that is tangential to the outer surfaces of the inner capillaries, wherein, the outer radii of the outer capillaries are all a common first value or fall within a first range that is different than a common second value or a second range within which the outer radii of the inner capillaries fall.