A light diffusing optical fiber includes a glass core, a cladding, a phosphor layer surrounding the cladding, and a plurality of scattering structures positioned within the glass core, the cladding, or both. The phosphor layer includes two or more phosphors and is configured to convert guided light diffusing through the phosphor layer into emission light such that the color of the emission light has a chromaticity within a u-v chromaticity region on a CIE 1976 chromaticity space defined by: a first u-v boundary line and a second u-v boundary line that extend parallel to a planckian locus at a distance of 0.02 Duv from the planckian locus, a third u-v boundary line that extends along an isothermal line for a correlated color temperature of about 2000 K, and a fourth u-v boundary line that extends along an isothermal line for a correlated color temperature of about 10000 K.

The present disclosure provides optical fibers with an impact-resistant coating system. The fibers feature low microbending and high mechanical reliability. The coating system includes a primary coating and a secondary coating. The primary coating and secondary coating have reduced thickness to provide reduced radius fibers without sacrificing protection. The primary coating has a low spring constant and sufficient thickness to resist transmission of force to the glass fiber. The secondary coating has high puncture resistance. The outer diameter of the optical fiber is less than or equal to 200 m.

A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

An optical fiber according to an embodiment of the present disclosure includes a core and a cladding which surrounds the core. The cladding includes an inner cladding layer which surrounds the core and an outer cladding layer which surrounds the inner cladding layer. A maximum value n1max of a relative refractive index difference of the core, a minimum value n2min of a relative refractive index difference of the inner cladding layer, and a maximum value n3max of a relative refractive index difference of the outer cladding layer satisfy a relationship of n2min<n3max<n1max. A residual stress (r) at a radial position r satisfies |d(r)/dr|30 MPa/m in the cladding.

An array-type polarization-maintaining multi-core fiber includes a main outer cladding, fiber core units, and stress units. The fiber core units and the stress units are arranged to form a unit array including one central unit and any unit in the unit array being equidistantly arranged from adjacent units thereof. Provided is at least one pair of stress units, each pair of stress units being arranged symmetrical about one fiber core unit to form a polarization-maintaining fiber core unit. The fiber core units each include a fiber core and an inner cladding surrounding a core layer. A portion outside the fiber core units and the stress units is the main outer cladding. The fiber can greatly enhance spectral efficiency of an optical transmission system, and improve fiber communication capacity.

An optical fiber is formed from silica glass, and includes a core, a first cladding which surrounds the core and has a refractive index lower than the refractive index of the core, and a second cladding which surrounds the first cladding and has a refractive index that is lower than the refractive index of the core and higher than the refractive index of the first cladding. The second cladding is divided into an inner region that is in contact with the first cladding and an outer region which surrounds the inner region and has a thickness that is half the thickness of the second cladding or less, while being 5 m or more. The residual stress in at least a part of the outer region is a compressive stress.

Cable/line systems and related methods are provided. The cable/line systems include at least one central cable and an optical waveguide surrounding the cable. The optical waveguide includes an inner cladding, a core, and an outer cladding. Scattering structures are dispersed within the optical waveguide. The optical waveguide is configured to scatter light by way of the scattering structures away from the core to emit radial lighting along the length of the optical waveguide. The spectrum and/or luminance of the emitted light is controlled according to properties of the cable/line.

A quantum communication system that includes a multiphoton entanglement generator, a plurality of photon detector units, and a plurality of optical fiber links. The plurality of photon detector units include a first photon detector unit and a second photon detector unit. The multiphoton entanglement generator is structurally configured to output more than two entangled photons. The plurality of optical fiber links comprise a first optical fiber link optically coupled to the multiphoton entanglement generator and disposed between the multiphoton entanglement generator and the first photon detector unit. The plurality of optical fiber links comprise a second optical fiber link optically coupled to the multiphoton entanglement generator and disposed between the multiphoton entanglement generator and the second photon detector unit. Further, at least one of the plurality of optical fiber links has a core, a cladding, and a scattering region having a plurality of scattering structures.

The invention relates to an optical fiber 1 comprising a core 2 and a cladding 3 surrounding the core 2 and having an outer diameter of 125 m, the optical fiber 1 comprising a cured primary coating 4 directly surrounding the cladding 3 and a cured secondary coating 5 directly surrounding the cured primary coating 4, said cured primary coating 4 having a thickness t.sub.1 between 10 and 18 m and an in-situ tensile modulus Emod.sub.1 between 0.10 and 0.18 MPa, said cured secondary coating 5 having a thickness t.sub.2 lower or equal to 18 m and an in-situ tensile modulus Emod.sub.2 between 700 and 1200 MPa, wherein said first and second thicknesses and said first and second in-situ tensile moduli satisfy the following equation: 4%<(t.sub.1t.sub.2Emod.sub.1Emod.sub.2.sup.3)/(t.sub.1_normt.sub.2_normEmod.sub.1_normEmod.sub.2_norm.sup.3)<50%.

An apparatus for scattering light may include: an optical fiber having a first length; and a sleeve, having a second length shorter than the first length, around the optical fiber. The optical fiber may include: a core; and cladding around the core. The sleeve may include fiber-optic material. The fiber-optic material may be substantially polymer-free. An outer surface of the sleeve may be roughened to scatter the light out of the sleeve through the roughened surface. A method of forming an apparatus for scattering light may include: providing a sleeve having a first length, the sleeve having inner and outer surfaces; providing an optical fiber having a second length longer than the first length; passing the sleeve around the optical fiber or threading the optical fiber through the sleeve; and roughening at least a portion of the outer surface of the sleeve.