Abstract: Disclosed herein are optical waveguide fibers comprising: (I) a core comprising an outer radius r1, a maximum refractive index delta percent ?1max and core alpha, ?, of larger than 5; and (II) a cladding surrounding the core, the cladding comprising: (i) an inner cladding region having outer radius r2 and refractive index delta percent ?2, wherein ?1max>?2; (ii) a trench region surrounding the inner cladding region, the trench region having an outer radius, r3 where r3?10 microns and refractive index delta percent ?3; and (iii) an outer cladding region having chlorine concentration of ?1.2 wt. % surrounding the trench region and comprising refractive index delta percent ?4, wherein ?1max>?4 and ?2>?3, and ?4>?3 and wherein the difference between ?4 and ?3 is ?0.12 percent.

Abstract: The present embodiment relates to an MCF having a low transmission loss and having a structure for reducing a transmission loss and effectively suppressing an inter-core XT. The uncoupled MCF includes alkali metal having a predetermined concentration in which each of a plurality of cores contributes to reduction in the transmission loss, and a core pitch is set so that a sum h_total of power coupling coefficients of a specific core and the remaining all cores of the plurality of cores is 2.3×10?4/km or less.

Abstract: The present embodiment relates to a CMCF including a structure to achieve more efficient reduction in transmission loss by suppressing decrease in concentration of alkali metal due to diffusion of alkali metal. In the CMCF including a plurality of cores, a power coupling coefficient h between adjacent cores is set to 1×10?3/m or more, to maintain an optical coupling state between the adjacent cores. In addition, alkali metal contributing to reduction in transmission loss is added to each of the cores such that a stress maximum value ?_max between adjacent cores has a negative value.

Abstract: A bending-insensitive single-mode fiber with ultralow attenuation includes a core layer and cladding layers. The cladding layers includes an inner cladding layer surrounding the core layer, a trench cladding layer surrounding the inner cladding layer, an auxiliary outer cladding layer surrounding the trench cladding layer, and an outer cladding layer surrounding the auxiliary cladding layer. The core layer has a radius of 3.0 to 3.9 ?m and a relative refractive index of ?0.04% to 0.12%. The inner cladding layer has a radius of 8 to 14 ?m and a relative refractive index ?0.35% to ?0.10%. The trench cladding layer has a radius of 14 to 20 ?m and a relative refractive index of ?0.6% to ?0.2%. The auxiliary outer cladding layer has a radius of 35 to 50 ?m and a relative refractive index of ?0.4% to ?0.15%. The outer cladding layer is a pure silica glass layer.

Abstract: A system and method are provided for distributed acoustic sensing in a multicore optical fiber. The system includes a transmitter for simultaneously propagating a sequence of M light pulses through the multicore optical fiber using a spatial mode selected from a set of N spatial modes provided by a spatial mode selector for the transmitter that is coupled to an input to the multicore optical fiber, with M and N being respective integers greater than one. The system further includes a receiver for receiving the sequence of M light pulses at an output of the multicore optical fiber and detecting an environmental perturbation in the multicore optical fiber based on an evaluation of a propagation of the sequence of M light pulses through the multicore optical fiber.

Abstract: An optical network having at least one star coupler comprising transmit and receive optical mixers which are respectively optically coupled to transmitters and receivers of a plurality of optical-electrical media converters. Each optical-electrical media converter comprises a respective receiver optically coupled to the receive optical mixer by way of plastic optical fibers and a respective transmitter optically coupled to the transmit optical mixer by way of plastic optical fibers. The output plastic optical fibers attached to an output face of the receive optical mixer have a diameter less than the diameter of the input plastic optical fibers attached to an input face of the receive optical mixer.

Abstract: An electronic distance meter includes an optical unit which emits light to a target object and receives the light reflected by the target object with a light receiving element, a measuring unit which calculates a length of round-trip time taken for the light to make a round trip to the target object and measures a distance to the target object according to the round-trip time of the received light, a light receiving system which receives and condenses the light reflected by the target object, and an optical guide which guides the light condensed by the light receiving element to the light receiving system, including a multi-mode graded index fiber and a multi-mode step index fiber coupled with each other.

Abstract: A fully dense ceramic and/or other inorganic fiber containing elongated crystal grains in and around the fiber center and oriented along the fiber axis, with a smooth transition to more equiaxed grains towards the radial periphery of the fiber, and method for producing such.

Abstract: An optical interconnection device including: a first element layer formed on a substrate; a second element layer disposed on the first element layer and receiving an optical signal; and a mode converter interposed between the first element layer and the second element layer, and eliminating a difference between an effective refractive index of the first element layer and an effective refractive index of the second element layer and match a mode profile, wherein the first element layer, the mode converter, and the second element layer are sequentially disposed on respective planes spaced apart from each other on the substrate, and one end of the mode converter overlaps a part of the second element layer, and the other end of the mode converter overlaps a part of the first element layer.

Abstract: One of embodiments relates to an optical fiber in which an alkali metal element is efficiently doped to its core to suppress transmission loss from increasing. A mean concentration or a concentration distribution of the alkali metal element is adjusted such that 0.48 or less is obtained as an weighted value obtained by weighting a distribution of field intensity of guided light at a wavelength of 1550 nm, with respect to a radial direction distribution of a ratio ID2/I?3 of an intensity ID2 of Raman scattering light by a silica three-membered ring structure and an intensity I?3 of Raman scattering light by a Si—O stretching vibration, in a cross-sectional region having a diameter of 20 ?m.

Abstract: A hybrid optical fiber integrates features of multimode optical fibers and single-mode optical fibers. The hybrid optical fiber possesses an optical core having a first core region and a second core region to provide improved optical mode coupling ratio for single-mode transmission while maintaining a broad bandwidth for multimode transmission. The hybrid optical fiber's optical core may optionally include a depressed trench positioned between the optical core's first core region and the optical core's second core region to reduce modal dispersion and to improve modal bandwidth during multimode transmissions.

Abstract: A waveguide includes a segment with a substantially uniform cure profile and related methods and systems for making and using the same. The waveguide is formed by modifying a laser beam used to write the waveguide to provide a substantially uniform cure profile in the waveguide. A marker characteristic of laser writing may be present in the waveguide. A method or system modifies an intensity profile or a shape profile of a laser beam to proactively compensate for exposure convolution based on the characteristics of the laser beam spot profile. A convolution compensator is positioned in the path of the laser beam to modify the beam spot profile during writing to form the one or more segments of the waveguide in a photo-curable layer.

Abstract: Disclosed herein are optical waveguide fibers comprising: (I) a core comprising an outer radius r1, a maximum refractive index delta percent ?1 max and core alpha, ?, of larger than 5; and (II) a cladding surrounding the core, the cladding comprising: (i) an inner cladding region having outer radius r2 and refractive index delta percent ?2, wherein ?1max>?2; (ii) a trench region surrounding the inner cladding region, the trench region having an outer radius, r3 where r3?10 microns and refractive index delta percent ?3; and (iii) an outer cladding region having chlorine concentration of ?1.2 wt. % surrounding the trench region and comprising refractive index delta percent ?4, wherein ?1max>?4 and ?2>?3, and ?4>?3 and wherein the difference between ?4 and ?3 is ?0.12 percent.

Abstract: An optical fiber with large effective area, low bending loss and low attenuation. The optical fiber includes a core, an inner cladding region, and an outer cladding region. The core region includes a spatially uniform updopant to minimize low Rayleigh scattering and a relative refractive index and radius configured to provide large effective area. The inner cladding region features a large trench volume to minimize bending loss. The core may be doped with Cl and the inner cladding region may be doped with F.

Abstract: An optical fiber including a multimode core having a radius, R1, and a maximum relative refractive index, ?1MAX, at a wavelength ?0, an inner clad layer surrounding the core and having a radial thickness, T2, and a minimum relative refractive index, ?2MIN, of about 0.0% at a wavelength of ?0, an intermediate clad layer surrounding the inner clad layer and having a radial thickness, T3, and a maximum relative refractive index ?3MAX and an outer clad layer surrounding the inner clad layer and having a radial thickness, T4, and a maximum relative refractive index, ?4MIN, at a wavelength of ?0. The optical fiber satisfies the following relationship: ?1MAX>?3MAX>?2MIN, and the optical fiber exhibits an overfilled bandwidth of greater than or equal to about 1.5 GHz-km at ?0.

Abstract: An optical delivery waveguide for a material laser processing system includes a small lens at an output end of the delivery waveguide, transforming laser beam divergence inside the waveguide into a spot size after the lens. By varying the input convergence angle and/or launch angle of the laser beam launched into the waveguide, the output spot size can be continuously varied, thus enabling a continuous and real-time laser spot size adjustment on the workpiece, without having to replace the delivery waveguide or a process head. A divergence of the laser beam can also be adjusted dynamically and in concert with the spot size.

Abstract: Annealing treatments for modified titania-silica glasses and the glasses produced by the annealing treatments. The annealing treatments include an isothermal hold that facilitates equalization of non-uniformities in fictive temperature caused by non-uniformities in modifier concentration in the glasses. The annealing treatments may also include heating the glass to a higher temperature following the isothermal hold and holding the glass at that temperature for several hours. Glasses produced by the annealing treatments exhibit high spatial uniformity of CTE, CTE slope, and fictive temperature, including in the presence of a spatially non-uniform concentration of modifier.

Abstract: An apparatus for converting fiber mode to waveguide mode. The apparatus includes a silicon substrate member and a dielectric member having an elongated body. Part of the elongated body from a back end overlies the silicon substrate member and remaining part of the elongated body up to a front end is separated from the silicon substrate member by a second dielectric material at an under region. The apparatus also includes a waveguide including a segment from the back end to a tail end formed on the dielectric member at least partially overlying the remaining part of the elongated body. The segment is buried in a cladding overlying entirely the dielectric member. The cladding has a refractive index that is less than the waveguide but includes an index-graded section with decreasing index that is formed at least over the segment from the tail end toward the back end.

Abstract: Described is a technique for optimizing the design and manufacture of broadband MMFs. MMFs for use in CWDM applications are specifically described.

Abstract: An optical network having at least one star coupler comprising transmit and receive optical mixers which are respectively optically coupled to transmitters and receivers of a plurality of optical-electrical media converters. Each optical-electrical media converter comprises a respective receiver optically coupled to the receive optical mixer by way of plastic optical fibers and a respective transmitter optically coupled to the transmit optical mixer by way of plastic optical fibers. The output plastic optical fibers attached to an output face of the receive optical mixer have a diameter less than the diameter of the input plastic optical fibers attached to an input face of the receive optical mixer.

Abstract: An optical fiber comprises a glass fiber including a core and a cladding surrounding the core, a non-strippable resin layer that adheres to and covers a surface of the glass fiber, and a buffer layer that covers the non-strippable resin layer, when pullout force measurement in which a length of 10 mm of each of the glass fiber and the non-strippable resin layer is pulled out at a tensile speed of 5 mm/min from the buffer layer is performed, a pullout force at 23° C. is 1.0 kg or less and a pullout force at 95° C. is 0.50 kg or less.

Abstract: A waveguide a core extending along a light propagation and a coupling layer adjacent one side of the core along the light propagation direction. A gradient index material is adjacent to at least one side of the coupling layer. The gradient index material has a first refractive index proximate the coupling layer and a second refractive index away from the coupling layer. The gradient index material is configured to direct light from an input facet to the core layer.

Abstract: An apparatus includes a multi-mode optical fiber having a selected plurality of optical propagating modes. The selected plurality may include only a proper subset of or may include all of the optical propagating modes of the multi-mode optical fiber. Each optical propagating mode of the selected plurality has a group velocity that varies over a corresponding range for light in, at least, one of the optical telecommunications C-band, the optical telecommunications L-band, and the optical telecommunications S-band. The ranges corresponding to different ones of the modes of the selected plurality are non-overlapping. The ranges of a group velocity-adjacent pair of the ranges are separated by a nonzero gap of less than about 10,000 meters per second.

Abstract: The present invention relates to an MMF with a structure for relaxing wavelength dependence of transmission bandwidth. In the MMF, a doping amount of a dopant for control of refractive index is adjusted, so as to make each of an OFL bandwidth at a wavelength of 850 nm and an OFL bandwidth at a wavelength of at least one of 980 nm, 1060 nm, and 1300 nm become not less than 1500 MHz·km, make the OFL bandwidth at the wavelength of at least one of 980 nm, 1060 nm, and 1300 nm become wider than the OFL bandwidth at the wavelength of 850 nm, and effectively suppress increase in transmission loss.

Abstract: An optical fiber cable has a sectional area of Ac [?m2] and housing a number N of optical fibers. A transmission loss ?dB [dB/km], a mode field diameter W [?m], an effective area Aeff [?m2], an effective length Leff [km], and a wavelength dispersion D [ps/nm/km] of each of the optical fibers at a wavelength of 1550 nm satisfy a predetermined equation.

Abstract: A multimode optical fiber includes a central core surrounded by an outer cladding. The central core has a graded-index profile with respect to the outer cladding and an outer radius r1 of between about 30 microns and 50 microns (e.g., between about 35 microns and 45 microns). The optical fiber also includes an inner cladding positioned between the central core and the outer cladding, and a depressed trench positioned between the inner cladding and the outer cladding. The multimode optical fiber exhibits reduced bending losses.

Abstract: A single mode optical fiber having a core made from silica and less than or equal to about 6.5 weight % germania and having a maximum relative refractive index ?1MAX. The optical fiber also has an inner cladding surrounding the core and having a minimum relative refractive index ?2MIN. A difference between a softening point of the core and a softening point of the inner cladding is less than or equal to about 20° C., and ?1MAX>?2MIN. The single mode optical fiber may also have an outer cladding surrounding the inner cladding made from silica or SiON. The outer cladding has a maximum relative refractive index ?3MAX, and ?3MAX>?2MIN. A method for manufacturing an optical fiber includes providing a preform to a first furnace, the preform, drawing the optical fiber from the preform, and cooling the drawn optical fiber in a second furnace.

Abstract: The present invention generally relates to the field of fiber optics, and more particularly, to apparatuses, systems, and methods directed towards improving effective modal bandwidth within a fiber optic communication environment. In an embodiment, a multimode optical fiber in accordance with the present invention comprises a core and cladding material system where the refractive indices of the core and cladding are selected to modify the shape of the profile dispersion parameter, y, as a function of wavelength in such a way that the alpha parameter (?-parameter), which defines the refractive index profile, produces negative relative group delays over a broad range of wavelengths. The new shape of the profile dispersion parameter departs from traditional fibers where the profile dispersion parameter monotonically decreases around the selected wavelength that maximizes the effective modal bandwidth (EMB).

Abstract: A multimode optical fiber is provides, which includes an optical core and an optical cladding surrounding the optical core. The optical core has a refractive graded-index profile. The optical cladding includes: an inner layer surrounding the optical core, an intermediate layer, called a “depressed trench”, surrounding the inner layer, and an outer layer surrounding the depressed trench and having a constant refractive index. The depressed trench has a width W and a negative refractive index difference ?nt with respect to the outer layer, and is designed so as to satisfy the following inequality: |0.585677?114.681×S+13.7287×S2+18.7343×S×W?4.61112×S×?nt.103?0.913789×W×?nt.103|+2×W×?nt.103<?30 wherein: S is the width of the inner cladding, which is included between 0.6 ?m and 1.6 ?m; ?nt is included between ?11.10?3 and ?4.10?3; and W×?nt.103 is lower than ?25 ?m.

Abstract: An optical fiber having a core comprising silica and greater than 1.5 wt % chlorine and less than 0.5 wt % F, said core having a refractive index ?1MAX, and a inner cladding region having refractive index ?2MIN surrounding the core, where ?1MAX>?2MIN.

Abstract: Embodiments of the invention relate to a hydrogen-resistant optical fiber with a core having a central axis. The core may include only silica, or only silica and fluorine, while a cladding region surrounding the core may be made of silica and fluorine, along with at least one of germanium, phosphorus, and titanium.

Abstract: An optical fiber with large effective area, low bending loss and low attenuation. The optical fiber includes a core, an inner cladding region, and an outer cladding region. The core region includes a spatially uniform updopant to minimize low Rayleigh scattering and a relative refractive index and radius configured to provide large effective area. The inner cladding region features a large trench volume to minimize bending loss. The core may be doped with Cl and the inner cladding region may be doped with F.

Abstract: The specification describes multimode optical fibers with specific design parameters, i.e., controlled refractive index design ratios and dimensions, which render the optical fibers largely immune to moderately severe bends. The modal structure in the optical fibers is also largely unaffected by bending, thus leaving the optical fiber bandwidth essentially unimpaired. Bend performance results were established by DMD measurements of fibers wound on mandrels vs. measurements of fibers with no severe bends. Additional embodiments of the present invention describe an improved optical link when the inventive multimode fiber is connected to standard or conventional multimode fibers.

Abstract: Methods and apparatus for delivering a neurostimulator to a target tissue are provided which may include any number of features. One feature is a delivery tool comprising a handle portion, an elongate shaft comprising a contoured distal portion, a visualization system embedded in the elongate shaft, and an insertion groove on the elongate shaft configured to deploy the neurostimulator. The contoured distal portion can be shaped and configured to maintain contact with a posterior maxilla and elevate a periosteum off of the posterior maxilla to avoid soft tissue dissection. In some embodiments, the neurostimulator is implanted in close proximity to or touching the sphenopalatine ganglion.

Abstract: An apparatus for converting fiber mode to waveguide mode. The apparatus includes a silicon substrate member and a dielectric member having an elongated body. Part of the elongated body from a back end overlies the silicon substrate member and remaining part of the elongated body up to a front end is separated from the silicon substrate member by a second dielectric material at an under region. The apparatus also includes a waveguide including a segment from the back end to a tail end formed on the dielectric member at least partially overlying the remaining part of the elongated body. The segment is buried in a cladding overlying entirely the dielectric member. The cladding has a refractive index that is less than the waveguide but includes an index-graded section with decreasing index that is formed at least over the segment from the tail end toward the back end.

Abstract: An optical fiber cable has a sectional area of Ac [?m2] and housing a number N of optical fibers. A transmission loss ?dB [dB/km], a mode field diameter W [?m], an effective area Aeff [?m2], an effective length Leff [km], and a wavelength dispersion D [ps/nm/km] of each of the optical fibers at a wavelength of 1550 nm satisfy a predetermined equation.

Abstract: Described is a general strategy of bend-compensated, single-mode LMA fibers extended into a regime with higher total index contrast and where a larger gradient is used to cancel the perturbation of a tighter anticipated bend.

Abstract: Various technologies pertaining to an on-chip entangled photon source are described herein. A light source is used to pump two resonator cavities that are resonant at two different respective wavelengths and two different respective polarizations. The resonator cavities are coupled to a four-wave mixing cavity that receives the light at the two wavelengths and outputs polarization-entangled photons.

Abstract: An optical fiber for efficient coupling of optical signals to photonic devices. The glass optical fiber includes a core region, an optional inner cladding region, a depressed index region, and an outer cladding region. The relative refractive index profile of the fiber is designed to provide large effective area and low bending losses at wavelengths of interest for photonic devices. The photonic devices may be silicon photonic devices with an operating wavelength at or near 1310 nm.

Abstract: Multicore optical fibers that include between two and ten multimode cores surrounded by a cladding matrix and symmetrically arranged about a fiber axis are disclosed, with no core running along the fiber axis. The cores include a trench to stabilize delays of the higher order modes, which tend to propagate faster than do the central modes due to the amount of power at the core-clad interface. The trench also suppresses crosstalk and power leakage. The core configuration promotes efficient optical alignment and optical coupling with other multicore optical fibers or light sources, such as VSCEL and silicon-photonics light sources.

Abstract: An optical waveguide having a cladding layer formed of high-purity glass, or a cladding layer formed of high-purity isotope-proportion modified glass, and with a core of high-purity isotope-proportion-modified glass with the index of refraction of the core glass greater than the index of refraction of the cladding glass, said high-purity isotope-proportion-modified core material having a Si-29-isotope proportion at most 4.447% Si-29 (atom/atom) of all silicon atoms in said core, or at least 4.90% of Si-29 (atom/atom) atoms in said core, or having a Ge-73 isotope proportion of at most 7.2% Ge-73 (atom/atom) of all germanium atoms in said core, or at least 8.18% of Ge-73 (atom/atom) of Germanium atoms in said core region.

Abstract: A multimode optical fiber includes a central core and an outer cladding (e.g., an outer optical cladding). Typically, the optical fiber's central core is a depressed, central core having an alpha-index profile (i.e., a graded-index profile), an outer radius r1, and a maximum refractive index difference ?n1 with respect to the outer cladding. The central core's alpha-index profile has a minimum refractive index at the central core's outer radius r1 that corresponds to a refractive index difference ?nend with respect to the outer cladding. Exemplary optical-fiber embodiments may include an inner cladding having an outer radius r2 and a width w2. Exemplary optical-fiber embodiments may include a buried trench having a width w3 and an outer radius r3. Furthermore, exemplary optical-fiber embodiments may include an intermediate cladding having an outer radius r4 and a width w4.

Abstract: An optical fiber including a multimode core having a radius, R1, and a maximum relative refractive index, ?1MAX, at a wavelength ?0, an inner clad region surrounding the core and having a radial thickness, T2, and a minimum relative refractive index, ?2MIN, of about 0.0% at a wavelength of ?0, and an outer clad layer, which is doped with chlorine at greater than or equal to 0.5 weight %, surrounding the inner clad region and having a radial thickness, T3, and a maximum relative refractive index, ?3MAX, at a wavelength of ?0. The optical fiber satisfies the following relationship: ?1MAX>?3MAX>?2MIN, and the optical fiber exhibits an overfilled bandwidth of greater than or equal to about 1.5 GHz-km at ?0.

Abstract: A multimode optical fiber includes a central core surrounded by an outer cladding. The central core has a graded-index profile with respect to the outer cladding and an outer radius r1 of between about 30 microns and 50 microns (e.g., between about 35 microns and 45 microns). The optical fiber also includes an inner cladding positioned between the central core and the outer cladding, and a depressed trench positioned between the inner cladding and the outer cladding. The multimode optical fiber exhibits reduced bending losses.

Abstract: A graded refractive index bending-resistant multimode optical fiber includes a core layer and claddings. The core layer has a radius in a range of 20-50 ?m; refractive indexes being a graded refractive index distribution with a distribution exponent ? in a range of 1.89-1.97; and a maximum relative refractive index difference (RRID) ?1% max in a range of 0.9%-2.72%. The claddings has an inner cladding surrounding the core layer, an intermediate cladding surrounding the inner cladding and an outer cladding surrounding the inner cladding. The inner cladding has a radius in a range of 22-57 ?m, and an RRID ?2% in a range of ?0.02%-0.02%. The intermediate cladding is a pure quartz glass layer, and has a radius in a range of 32-60 ?m, and an RRID ?3% in a range of ?0.01%-0.01%.

Abstract: A method of manufacturing a radiation-resistant optical fiber and a thus-obtained radiation-resistant optical fiber, the method includes the following steps: a) manufacturing a silica optical fiber preform; b) forming, in the preform, a longitudinal cavity; c) drawing the preform so as to form an optical fiber (1) including a core (2), an optical cladding (6) and at least one longitudinal cavity (3) having at least one opening (13) at one end of the optical fiber (1); d) applying, during step c) of fiber drawing, a gas-tight coating (4); e) exposing the optical fiber (1) to a gaseous substance, including preferably gaseous hydrogen and/or gaseous deuterium, in such a way to incorporate the gaseous substance in silica via the opening (13); and f) closing any opening (13) at both ends of the optical fiber.

Abstract: According to an embodiment of the disclosure, a system for producing a higher power laser beam is provided. The system includes an optical fiber having a length. The optical fiber is configured to receive inputs from multiple laser pumps and an input from a Stokes seed laser pump. The optical fiber has a core that is doped. The core, when viewed from a cross-section of the optical fiber, has a higher concentration of doping at a location near an axis of the optical fiber than a location further from the axis of the optical fiber. The optical fiber is also configured to convert pump power to Stokes power along the length of the optical fiber when subjected to a Stimulated Raman Scattering (SRS) process.

Abstract: An optical fiber comprises a glass portion comprising a core and a cladding surrounding the core, and, a resin portion comprising a non-removable resin layer tightly covering the glass portion and comprising an ultraviolet curing resin and a buffer layer covering the non-removable resin layer and comprising an ultraviolet curing resin. A diameter of the core falls within a range from 20 ?m or larger to 80 ?m or smaller, and an outer diameter of the non-removable resin layer falls within a range from 120 ?m or larger to 127 ?m or smaller. In this optical fiber, when flexural rigidity of the glass portion is EI(g) and flexural rigidity of the resin portion is EI(r), EI(g)?EI(r) is satisfied.

Abstract: A light-diffusing optical fiber that includes a core region in the fiber that comprises a core glass composition; and an inner cladding in the fiber that surrounds the core region and comprises a cladding glass composition that substantially differs from the core glass composition. The core glass composition comprises a doped, low-melting point silica glass having less than 90% by weight SiO2, and the numerical aperture of the fiber is greater than or equal to 0.4. Further, light-diffusing optical fiber bundles that include a jacket comprising a scattering element; and a plurality of the light-diffusing optical fibers arranged within the jacket. Also, light-diffusing optical fiber bundles that include a transparent jacket; and a plurality of the light-diffusing optical fibers arranged within the jacket, the fibers further configured with an outer cladding having a plurality of scattering elements.

Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.5×10?3. For the inner cladding layer, the diameter is 16.5-20 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 33-40 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.