Abstract: The present invention provides light-emitting diode (LED) devices comprises compositions and containers of hermetically sealed luminescent nanocrystals. The present invention also provides displays comprising the LED devices. Suitably, the LED devices are white light LED devices.

Abstract: Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.

Abstract: The present invention provides an optical fiber and method of making the same. The optical fiber includes a body for transmitting light. The body has an anisotropic refractive index wherein the anisotropic refractive index offsets changes in the refractive index of the fiber caused by bending the fiber. The fiber body may further include a core and cladding.

Abstract: The invention relates to an optical fiber comprising a core and a cladding, wherein the core is made of a glass composition having a near-zero electrostrictive coefficient M11, to reduce the effect of stimulated Brillouin Scattering (SBS). The invention further relates to a compensation fiber segment for connection to a silica optical fiber, the compensation fiber segment being made of a glass composition having an electrostrictive coefficient that opposes that of the silica optical fiber so that an acoustic wave transmitted to compensation fiber segment from the silica optical fiber will generate an acoustic wave within the compensation fiber segment that is about 180 degrees out of phase with the that acoustic wave transmitted from the silica optical fiber, thereby minimizing the effect of stimulated Brillouin Scattering.

Abstract: A method of making a calcium-fluoride layer formed on an object surface for more wear resistance includes the steps of coating sodium fluoride to a surface of an object having calcium, whereby the calcium fluoride and the calcium are inverted to become a calcium-fluoride layer on the surface of the object after a chemistry reaction; preparing a CO2 laser device having a CO2 laser emitter for emitting CO2 laser; and applying irradiation of the CO2 laser via the CO2 laser emitter to the calcium-fluoride layer for at least five seconds. In light of this, the wear resistance of the calcium-fluoride layer is enhanced for at least 34%, the absorption rate of the fluoride is increased for at least 23%, and the surface of the object has aesthetic and integral appearance.

Abstract: An optical hollow waveguide assembly (1) includes an optical hollow waveguide (2) for guiding illumination light (3). The hollow waveguide (2) has a tubular main body (6) with a continuous waveguide cavity (7). The waveguide cavity has an illumination light inlet (8) and an illumination light outlet (9). A cavity inner wall (10) of the waveguide cavity (7) is configured to be highly reflective for the illumination light (3) under grazing incidence. A gas source (12) has a fluid connection (13) to the waveguide cavity (7). The resulting hollow waveguide assembly exhibits a reduced risk of contamination of the hollow waveguide.

Abstract: Apparatus and a method for monitoring various conditions of a vehicle structure including an optical sensor comprising an optical fiber bearing a photonic crystal mounted to one end, an interrogation system including an optical signal generator interfacing with one or more of the optical sensors located remotely from the interrogation module, and a method of monitoring the vehicle structural health using the interrogation system.

Abstract: A modular system for the connection of an external communication network to a user network of a building includes: a user module including: a passage opening of a connection cable of the user network including optical fibers associated with respective users and adapters associated with respective optical fibers of the connection cable of the user network, and an operator module including: an inlet opening of at least one connection cable to the external communication network including optical fibers and an outlet opening of fiber optic connection elements connected to the external communication network and provided with a connector at a terminal end thereof. The user module and the operator module are structurally independent from each other and the external communication network is operatively associated with the user network by means of a connection of the connectors of the fiber optic connection elements with respective selected adapters of the user module.

Abstract: An optical routing element may include a planar dielectric photonic crystal which includes a lattice of holes having a first linear defect adjacent a second linear defect, with the two defects being separated by a central row of lattice holes. The first linear defect in the lattice of holes may form a first single mode line defect waveguide, and the second linear defect in the lattice of holes may form a second single mode line defect waveguide. Optical energy may be selectively coupled between the first and second waveguides across the central row of lattice holes. A free-carrier injector may be included to inject free-carriers into the dielectric photonic crystal, activation of which may alter selectivity of the optical coupling between the first and second waveguides. A plurality of optical routing elements with associated free-carrier injectors may be interconnected to form a bi-directional optical routing array.

Abstract: Fiber burning and/or overheating of the fiber feedthrough in high-power laser modules, which may cause catastrophic and/or collateral damage, may be addressed by providing an optical fiber assembly designed to withstand overheating due to errant high power laser light that is directed toward the input core of a fiber but may be at least partially misaligned. The optical fiber may be secured within a mount having a passageway such that the end face of the optical fiber extends past an opening of the passageway to a focal plane of the incident light. The end of the optical fiber may include a section that has a reduced or absent cladding layer (e.g., etched to form a tapered cladding region) so as to reduce the amount of light captured by the cladding and/or to leak the light out quickly.

Abstract: In one embodiment, an optical fiber includes a first layer having a first refractive index and a second layer surrounding the first layer, where the second layer has a second refractive index, an inner radius, and an outer radius. The optical fiber also includes a third layer surrounding the second layer, where the third layer has a third refractive index, where the first refractive index is less than the second refractive index, where the third refractive index is less than the second refractive index, and where a ratio of the outer radius to the inner radius is less than 1.5.

Abstract: A coherent mixer includes a multi-mode waveguide that has a side surface and an end; a waveguide group including a plurality of semiconductor regions connected to the end; a first semiconductor region that has a side surface extending substantially parallel to the side surface of the multi-mode waveguide; and an external semiconductor region having a side surface extending substantially parallel to an edge of the waveguide group. The side surface of the semiconductor region is spaced apart from the side surface of the multi-mode waveguide by a distance smaller than or equal to a reference value. The side surface of the external semiconductor region is spaced apart from the edge of the waveguide group by a distance smaller than or equal to the reference value. The reference value is a maximum value of distances between arbitrary adjacent semiconductor regions in the waveguide group.

Abstract: There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

Abstract: An optical fiber preform, and method for fabricating, having a first core, a second core spaced from the first core and first and second regions, the first region having an outer perimeter having a first substantially straight length and the second region having an outer perimeter having a second substantially straight length facing the first straight length. One of the regions can comprise the first core and the other comprises the second core. The preform can be drawn with rotation to provide a fiber wherein a first core of the fiber is multimode at a selected wavelength of operation and a second core of the fiber is spaced from and winds around the first core and has a selected longitudinal pitch. The second core of the fiber can couple to a higher order mode of the first core and increase the attenuation thereof relative to the fundamental mode of the first core.

Abstract: A method of forming a metal structure. The method comprises providing a dispersion of metal nanoparticles and a solution comprising a transient polymer and solvent. The dispersion of metal nanoparticles and the solution are formed by coaxially electrospinning into a fiber comprising the metal nanoparticles and the transient polymer. The fiber is heated to decompose the transient polymer and form a metallic structure.

Abstract: Optical fiber waveguides and related approaches are implemented to facilitate communication. As may be implemented in accordance with one or more embodiments, a waveguide has a substrate including a lattice structure having a plurality of lattice regions with a dielectric constant that is different than that of the substrate, a defect in the lattice, and one or more deviations from the lattice. The defect acts with trapped transverse modes (e.g., magnetic and/or electric modes) and facilitates wave propagation along a longitudinal direction while confining the wave transversely. The deviation(s) from the lattice produces additional modes and/or coupling effects.

Abstract: The connection device for liquid-core optical fiber comprises a sleeve traversed by a channel comprising a plurality of communicating stacked conduits, a first conduit being formed from an end of the sleeve and being arranged to receive, in a sealed manner, at the corresponding end of the sleeve, one end of the optical fiber, and a second conduit being formed communicating with the first conduit, and closing means that hermetically seal the end of the second conduit opposite the end that communicates with the first conduit, the sleeve further having a third conduit for filling the internal volume of the second conduit when the latter is closed at one end by the closing device and the fiber is inserted into the first conduit, the third conduit transversely connecting the outside of the sleeve with the inside of the second conduit, and a sealing plug for hermetically sealing the port of the third conduit opening to the outside of the sleeve.

Abstract: Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.

Abstract: An optical coupling device includes a first and a second body. The first body receives first optical fibers. The first body has a first body optical surface and a first body partial top surface. First lenses are positioned on the first body optical surface. The second body receives second optical fibers. The second body has a second body optical surface and a second body partial top surface. Second lenses are positioned on the second body optical surface. Flexible connecting members connect the first body optical surface to the second body optical surface. When the coupling device is in a closed position, the first body partial top surface is in substantial contact with the second body partial top surface. When the coupling device is in an open position, the first body optical surface is opposite to the second body optical surface aligning the first lenses with the second lenses.

Abstract: The fiber comprises a core (2) having an index N and diameter of 10 ?m or more, surrounded by a ring (4) having an index N+?n and thickness ?R, and cladding (6) surrounding the ring and comprising for example air gaps (8). According to the invention: ?n?10?3 and ?R=?/(?n)? [1] where: 5×10?4 ?m???5×10?2 ?m and 0.5???1.5. The numbers ? and ? are dependent on the wavelength ? of the light guided by the fiber, the number of missing gaps therein, the diameter d of the gaps, the spacing ? thereof and N. To design the fiber, ?, the number of missing gaps, d/?, the core doping content, ? and ?n are chosen; and ?R is determined using equation [1] so as to obtain a flattened fundamental mode.

Abstract: Novel processing methods for production of high-refractive index contrast and low loss optical waveguides are disclosed. In one embodiment, a novel waveguide is produced by first depositing or growing a first low refractive index material layer as a cladding layer on top of a base substrate. Then, a first high refractive index material layer is deposited or transferred to the top of the cladding layer to form a slab core region. Subsequently, a second high refractive index material layer is deposited on top of the slab core region, and an etch mask layer is formed. Furthermore, the second high refractive index material layer is selectively etched by utilizing a dry-etching tool with high selectivity to the etch mask layer, and a second low refractive index material layer is deposited as a top cladding layer to encapsulate the second high refractive index material layer on top of lower cladding layers.

Abstract: The present invention relates to an optical fiber comprising at least a first end with an first end facet, the optical fiber comprising a core region capable of guiding light at a first wavelength ?; and a microstructured cladding region surrounding said core region. The cladding region comprises an inner cladding region and an outer cladding region. The inner cladding region comprises inner cladding features arranged in an inner cladding background material having a refractive index n1, said inner cladding features comprising thermally collapsible holes or voids. The outer cladding region comprising outer cladding features arranged in an outer cladding background material, said outer cladding features comprising solid material with refractive index n2, wherein n2 is lower than n1. The invention further relates to methods for splicing such an optical fiber to an optical component and to methods for using such an optical fiber.

Abstract: Novel methods and systems for miniaturized lasers are described. A photonic crystal is bonded to a silicon-on-insulator wafer. The photonic crystal includes air-holes and can include a waveguide which couples the laser output to a silicon waveguide.

Abstract: A hollow core fiber having polarization dependent loss is provided. The hollow core fiber embedded in a cellular cladding having a plurality of cells arranged in a nominally regular cellular lattice. A pre-determined number of cells at pre-determined locations within a cellular cladding are substituted by leakage cells that differ in at least one property including a physical or a chemical property, or both. The leakage cells collectively provide a leakage path that may preferably be made polarization sensitive, such that a core mode with a particular polarization state is selectively coupled to the cladding, thereby inducing polarization dependent loss. The leakage cells may be dispersed along a symmetry axis in a radial distance longer than one or more lattice spacing away from the core. The polarization dependent loss may be controlled further by asymmetric core shapes and/or by introducing additional surface features along the core-cladding interface.

Abstract: Each of a first clad region (12) and a second clad region (13) has holes (12a, 13a) which have identical diameters and are periodically formed so that the first clad region (12) and the second clad region (13) each have an effective refractive index lower than a refractive index of a core region (11), the effective refractive index of the first clad region (12) being lower than that of the second clad region (13).

Abstract: Disclosed and claimed herein is a hollow core coaxial cable, having a dielectric capillary with an inside wall and an outside wall, an inner conductive layer on the inside wall of the hollow core coaxial cable and an outer conductive layer on the outside wall of the hollow core coaxial cable, the conductive layers may be patterned. Further disclosed is a method of making the hollow core coaxial cable. Further disclosed are holey fiber coaxial cables, having a holey fiber capillary having an inside wall and an outside wall, an inner conductive layer on the inside wall of the hollow core coaxial cable and an outer conductive layer on the outside wall of the hollow core coaxial cable, the conductive layers may be patterned.

Abstract: A holey fiber includes: a core portion; an inner-cladding portion positioned at an outer periphery of the core portion, the inner-cladding portion having a plurality of inner holes formed in a layered structure around the core portion; and an outer-cladding portion positioned at an outer periphery of the inner-cladding portion, the outer-cladding portion having a plurality of outer holes formed in a layered structure around the inner-cladding portion. The inner holes are disposed to form a triangular lattice of which lattice constant ?1 is equal to or smaller than 2.0 ?m and to form equal to or greater than two layers. The outer holes are disposed to form a triangular lattice of which lattice constant ?2 is greater than the ?1 and equal to or larger than 3.0 ?m and to form equal to or greater than two layers. The overlap index is equal to or greater than 2.0%.

Abstract: An optical active fiber is configured with an asymmetrically-shaped core having at least one long axis and a shortest axis which extends transversely to the long axis. The outmost cladding of the active fiber is configured with a marking indicating the orientation of the short axis. The marking allows for bending the fiber so that the shortest axis extends along and lies in the plane of the bend thereby minimizing distortion of a mode which is guided by the asymmetrically-shaped core as light propagates along the bend.

Abstract: Light diffusing optical fibers for use in ultraviolet illumination applications and which have a uniform color gradient that is angularly independent are disclosed herein along with methods for making such fibers. The light diffusing fibers are composed of a silica-based glass core that is coated with a number of layers including a scattering layer.

Abstract: Illumination systems that include a plurality of illumination devices disposed within a water environment. Such illumination devices having a tube filled with water, at least one light source positioned to project light into the tube, and connected to the illumination devices via light carrying connectors, include one or more voids within each tube wall which extend substantially longitudinally and cause light incident below a critical angle to be reflected hack into the tube. Projected or reflected light above a critical angle that strikes a portion of the wall without a void is transmitted through the tube wall. By adjusting the ratio of voids to non-voids light can be delivered in a controlled manner.

Abstract: Air core optical fiber structures in which the cladding is composed of an engineered optical metamaterial having a refractive index less than unity for at least one specific wavelength band and provides for total internal reflection of optical energy between the air core and metamaterial cladding. According to certain examples, a method of guiding optical energy includes constructing a hollow core optical fiber with an all-dielectric optical metamaterial cladding, coupling optical energy into the optical fiber having an operating wavelength near a resonance of the metamaterial cladding, and guiding the optical energy within the hollow core optical fiber by total internal reflection.

Abstract: Embodiments of optical fiber may include cladding features that include a material (e.g., fluorine-doped silica glass) that may produce a very low relative refractive index difference with respect to cladding material in which the cladding features are disposed. This relative refractive index difference may be characterized by (n1?n2)/n1, where n1 is the index of refraction of the cladding material in which the cladding features are included, and n2 is the index of refraction of the cladding features. In certain embodiments, the relative refractive index difference may be less than about 4.5×10?3. In various embodiments, the configuration of the cladding features including, for example, the size and spacing of the cladding features, can be selected to provide for confinement of the fundamental mode yet leakage for the second mode and higher modes, which may provide mode filtering, single mode propagation, and/or low bend loss.

Abstract: An integrated circuit coupling device includes an integrated circuit package; and an optical data transmission medium connected to the integrated circuit package, and comprising a movable coolant, adapted to remove heat from the integrated circuit package, in operation.

Abstract: A random array of holes is created in an optical fiber by gas generated during fiber drawing. The gas forms bubbles which are drawn into long, microscopic holes. The gas is created by a gas generating material such as silicon nitride. Silicon nitride oxidizes to produce nitrogen oxides when heated. The gas generating material can alternatively be silicon carbide or other nitrides or carbides. The random holes can provide cladding for optical confinement when located around a fiber core. The random holes can also be present in the fiber core. The fibers can be made of silica. The present random hole fibers are particularly useful as pressure sensors since they experience a large wavelength dependant increase in optical loss when pressure or force is applied.

Abstract: A method and apparatus for transmitting light through a light absorbing medium in which a light transmissive fluid column or channel contiguous with the light absorbing medium is formed in the light absorbing medium. The light is introduced into a light inlet end of the column of light transmissive fluid, whereby the light is transmitted in the column of light transmissive fluid through the light absorbing medium until exiting a light outlet end of the column. The invention has applicability to the field of fiber optics and downhole applications of lasers, such as for wellbore drilling and completion activities.

Abstract: A multimode optical fiber includes: (i) a graded index glass core having a radius R1 in the range of 20 microns to 50 microns, a maximum relative refractive index ?1MAX in the range between 0.5% and 3%; a graded index having a profile with (a) by an alpha (?) parameter wherein 1.9???2.2, and (b) a deviation from the alpha profile in at least one region of the core, such that the difference in the refractive index delta of the core from that determined by the core alpha value, at the radius R1 is less than 0.001, and (ii) a cladding surrounding and in contact with the core, wherein the fiber has an bandwidth greater than 5000 MHz-km at a wavelength ? where ??800 nm.

Abstract: An optical device includes a hollow-core photonic-bandgap fiber, wherein at least a portion of the hollow-core photonic-bandgap fiber is adjustably axially twisted.

Abstract: Fiber structure including a core and a cladding, a central microstructure having a first plurality of longitudinal holes and which is adapted for guiding optical radiation and for birefringence in the core. Also included is a side microstructure having a second plurality of longitudinal holes is provided, wherein the side microstructure partly surrounds the central microstructure and provides a predetermined mechanical anisotropy, a pressure responsive unit for converting an isotropic pressure force to birefringence changes on the core, a lateral force responsive unit for converting a directional pressure force to birefringence changes on the core, a temperature responsive unit for converting temperature to birefringence changes on the core, and a birefringence responsive unit for converting birefringence in the core to wavelength information.

Abstract: Disclosed is an amplifying optical fiber that includes a central core that is suitable for transmitting and amplifying an optical signal and a surrounding optical cladding that is suitable for confining the optical signal transmitted in the central core. The central core is formed from a main matrix that contains nanoparticles doped with at least one rare earth element. The weight concentration of the rare earth dopants in the nanoparticles is typically between about 1 and 20 percent, and the nanoparticle concentration in the central core's main matrix is between about 0.05 percent and 1 percent by volume. The disclosed optical fiber incorporates rare earth ions at high concentrations yet avoids the phenomenon of photodarkening at high transmission power.

Abstract: Holey fibers provide optical propagation. In various embodiments, a large core holey fiber comprises a cladding region formed by large holes arranged in few layers. The number of layers or rows of holes about the large core can be used to coarse tune the leakage losses of the fundamental and higher modes of a signal, thereby allowing the non-fundamental modes to be substantially eliminated by leakage over a given length of fiber. Fine tuning of leakage losses can be performed by adjusting the hole dimension and/or spacing to yield a desired operation with a desired leakage loss of the fundamental mode. Resulting holey fibers have a large hole dimension and spacing, and thus a large core, when compared to traditional fibers and conventional fibers that propagate a single mode. Other loss mechanisms, such as bend loss and modal spacing can be utilized for selected modes of operation of holey fibers.

Abstract: An optical material can be formed by creating extremely small voids or gas-filled bubbles in a polymeric material, such as a thermoplastic or a fluoropolymer. The voids or gas-filled bubbles can reduce the refractive index of the optical material substantially below the polymeric material's refractive index. Dimensionally, the voids or gas-filled bubbles can be smaller than the wavelength of light that is intended to interact with the optical material, thereby avoiding undue scattering loss. The voids or gas-filled bubbles can be formed via adding particles of gas-generating material to the polymeric material and heating the resulting composition. The voids or gas-filled bubbles can form as the heat causes the polymeric material to melt and the particles to generate gas. The optical material can be utilized as a cladding to provide a high numerical aperture optical fiber, for example.

Abstract: An apparatus for medical treatment by means of laser light includes an optical conducting fiber which has a curved light emission end and includes a core, a cladding arranged above the core for conducting laser light coupled into the optical conducting fiber, and capillaries arranged in the cladding, wherein the capillaries run in a longitudinal direction of the optical conducting fiber at a radial distance from a longitudinal axis of the optical conducting fiber and form a capillary ring when viewed in cross-section, wherein the capillaries have cavities which are separated by bridges which have a width which is smaller than a wavelength of the laser light, wherein the laser light emerges from a forward surface of the light emission end and is transmitted in a direction which runs transverse to a substantially straight longitudinal section located directly in front of a curvature which defines the curved light emission end.

Abstract: A single-mode optical fiber for guiding an optical signal, wherein the core region is capable of guiding an optical signal in a fundamental core mode at an optical signal wavelength. A cladding region is arranged to surround the core region and includes an inner cladding region and an outer cladding region. The inner cladding region includes a background material and a plurality of inner cladding features arranged in the background material, wherein a plurality of the plurality of inner cladding features are of a first type of feature that includes an air hole surrounded by a high-index region comprising a high-index material that is larger than the refractive index of the inner cladding background material.

Abstract: Various embodiments described herein comprise a laser and/or an amplifier system including a doped gain fiber having ytterbium ions in a phosphosilicate glass. Various embodiments described herein increase pump absorption to at least about 1000 dB/m-9000 dB/m. The use of these gain fibers provide for increased peak-powers and/or pulse energies. The various embodiments of the doped gain fiber having ytterbium ions in a phosphosilicate glass exhibit reduced photo-darkening levels compared to photo-darkening levels obtainable with equivalent doping levels of an ytterbium doped silica fiber.

Abstract: An optical fiber according to an embodiment of the present invention is provided with a center core, a side core, and a cladding. The center core includes a ring part where a relative index difference varies discontinuously, in its peripheral region, and when a is a radius from a core center to an outside of the ring part and c is a radius to a position where the relative index difference is maximum in the side core, an index profile is realized in a shape where c/a is in the range of 2.25 to 2.50, so as to enable setting of a dispersion value, a cable cutoff wavelength, a bending loss in the diameter of 20 mm, and an effective area in desired ranges.

Abstract: Light-coupling systems and methods that employ light-diffusing optical fiber are disclosed. The systems include a light source and a light-diffusing optical fiber optically coupled thereto. The light-diffusing optical fiber has a core, a cladding and a length. At least a portion of the core comprises randomly arranged voids configured to provide substantially spatially continuous light emission from the core and out of the cladding along at least a portion of the length. A portion of the light-diffusing optical is embedded in an index-matching layer disposed adjacent a lower surface of a transparent sheet. Light emitted by the light-diffusing optical fiber is trapped within the transparent sheet and index-matching layer by total internal reflection and is scattered out of the upper surface of the transparent sheet by at least one scattering feature thereon.

Abstract: Holey fibers provide optical propagation. In various embodiments, a large core holey fiber comprises a cladding region formed by large holes arranged in few layers. The number of layers or rows of holes about the large core can be used to coarse tune the leakage losses of the fundamental and higher modes of a signal, thereby allowing the non-fundamental modes to be substantially eliminated by leakage over a given length of fiber. Fine tuning of leakage losses can be performed by adjusting the hole dimension and/or spacing to yield a desired operation with a desired leakage loss of the fundamental mode. Resulting holey fibers have a large hole dimension and spacing, and thus a large core, when compared to traditional fibers and conventional fibers that propagate a single mode. Other loss mechanisms, such as bend loss and modal spacing can be utilized for selected modes of operation of holey fibers.

Abstract: A random array of holes is created in an optical fiber by gas generated during fiber drawing. The gas forms bubbles which are drawn into long, microscopic holes. The gas is created by a gas generating material such as silicon nitride. Silicon nitride oxidizes to produce nitrogen oxides when heated. The gas generating material can alternatively be silicon carbide or other nitrides or carbides. The random holes can provide cladding for optical confinement when located around a fiber core. The random holes can also be present in the fiber core. The fibers can be made of silica. The present random hole fibers are particularly useful as pressure sensors since they experience a large wavelength dependant increase in optical loss when pressure or force is applied.

Abstract: An optical fiber comprising: (I) a germania doped central core region having outer radius r1 and (II) a maximum relative refractive index ?1max and a cladding region including (i) a first inner cladding region having an outer radius r2>5 microns and refractive index ?2; (ii) a and a second inner cladding region having an outer radius r3>9 microns and comprising refractive index ?3; and (iii) an outer cladding region surrounding the inner cladding region and comprising refractive index ?4, wherein ?1max>?4, ?2>?3, and wherein 0.01%??4??3?0.09%, said fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm, and 0.25?r1/r2?0.85.

Abstract: Apparatus and method are provided for transmitting at least one electro-magnetic radiation is provided. In particular, at least one optical fiber having at least one end extending along a first axis may be provided. Further, a light transmissive optical arrangement may be provided in optical cooperation with the optical fiber. The optical arrangement may have a first surface having a portion that is perpendicular to a second axis, and a second surface which includes a curved portion. The first axis can be provided at a particular angle that is more than 0° and less than 90° with respect to the second axis.