Abstract: An optical fiber having both low bend loss. The fiber has a central core region having refractive index ?1, an inner cladding region having an outer radius r2>17 microns and refractive index ?2 and a second cladding region surrounding the inner cladding region having refractive index ?3. The fiber profile segments may be arranged so that ?1>?3>?2. The fiber may exhibit a profile volume, V2 of the inner cladding region, calculated between r1 and r2, is at least 30% ?micron2.

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 22.5-27.5 ?m; refractive indexes being a gradient-graded refractive index distribution with a distribution exponent ? in a range of 1.99-2.06; and a maximum relative refractive index difference (RRID) ?1% max in a range of 0.9%-1.3%. 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 25.5-34.5 ?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 30.5-49.5 ?m, and an RRID ?3% in a range of ?0.01%-0.01%. The outer cladding has a radius in a range of 61.5-63.5 ?m, and an RRID ?4% is in a range of ?0.20%-0.30%.

Abstract: The invention relates to a bend insensitive gradient index multi-mode light conducting fiber comprising a leakage mode dependent optical core diameter that is uniform over its length and a numerical aperture that is uniform over its length, wherein for a light wavelength of 850 nm and an overfilled launch (OFL), the optical core diameter for a fiber length in a range between 2 m and 100 m decreases by less than 5% and the numerical aperture decreases by less than 2.5% and the curvature related attenuation increase for two turns and a curvature radius of 7.5 mm is less than 0.2 db.

Abstract: An optical fiber includes a core region having a longitudinal axis. A cladding region surrounds the core region. The core region and cladding region are configured to support and guide the propagation of signal light in a fundamental transverse mode in the core region in the directions of the axis. The fiber has a bend-induced gradient of its equivalent index of refraction indicative of a loss in guidance of the mode. At least a portion of cladding region has a graded index of refraction opposite the bend-induced gradient. The cladding region is configured to have a substantially flat equivalent index in response to a bend of the optical fiber.

Abstract: An inexpensive low-attenuation optical fiber 1 suitable for use as an optical transmission line in an optical access network is a silica based glass optical fiber and includes a core 11 including the center axis, an optical cladding 12 surrounding the core, and a jacket 13 surrounding the optical cladding. The core contains GeO2 and has a relative refractive index difference ?core, based on the optical cladding, greater than or equal to 0.35% and less than or equal to 0.50% and has a refractive index volume v greater than or equal to 0.045 ?m2 and less than or equal to 0.095 ?m2. The jacket has a relative refractive index difference ?J greater than or equal to 0.03% and less than or equal to 0.20%. Glass constituting the core has a fictive temperature higher than or equal to 1400° C. and lower than or equal to 1590° C. Residual stress in the core is compressive stress that has an absolute value greater than or equal to 5 MPa.

Abstract: A high confinement nonlinear optical fiber is provided along with methods of parametric amplification for use thereof The nonlinear optical fiber may include a plurality of concentric layers which are configured to provide different guiding regimes to low-frequency and high-frequency components through transverse geometry and refractive index profiling, thus reducing waveguide dispersion. The resulting optical fiber provides a parametric device with phase-matching in any spectral region of interest, such that a fiber optic parametric amplifier (FOPA) implementing the optical fiber can amplify in any spectral window of interest. A narrow-band FOPA configured to minimize phase mismatching is also provided for use with the optical fiber, and may be implemented as a light source or a monochromator.

Abstract: A multimode optical fiber, and a method of making the fiber, are provided according to the following steps and elements: forming a core preform with a graded refractive index that includes silica and an up-dopant; drawing the core preform into a core cane; forming an inner annular segment preform that includes silica soot and an up-dopant surrounding the core cane; and forming a depressed-index annular segment preform that includes silica soot surrounding the inner annular segment preform. The method also includes the steps: forming an outer annular segment preform that includes silica soot and an up-dopant surrounding the depressed-index annular segment preform; doping the inner, depressed-index and outer annular segment preforms simultaneously or nearly simultaneously with a down-dopant; and consolidating the segment preforms simultaneously or nearly simultaneously into inner, depressed-index and outer annular segments.

Abstract: Optical fiber designs are depicted with a core having an alpha profile inner portion and a steep vertical step between the core and a cladding with no shoulder, referred to herein as a truncated core. A further aspect of this invention can include a trench between the truncated core and cladding. In this embodiment, the core performs as not only as the primary light guiding structure, but now also functions essentially the same as that of a trench structure. Thus, what was formally a trench can now be much less negative or even positive. Another embodiment of the present invention includes an optical fiber having a truncated core with the addition of a ledge or shoulder between the core and vertical step, followed directly by a cladding.

Abstract: A single-mode optical fiber for transmitting optical signals includes a central core region for guiding the optical signals, and a cladding region surrounding the core region and including a void-containing annular layer containing randomly distributed voids, wherein the void-containing layer is doped with fluorine at a concentration of less than 1 wt % and has a radial thickness equal to or smaller than 3 ?m.

Abstract: The method described herein allows for melt stabilization and vapor-phase synthesis of a cesium germanium halide utilizing germanium dihalides formed in situ. This disclosure allows for the melting of cesium germanium halides without decomposition, which allows for growing crystals of these materials from the melt. This disclosure allows for a direct synthesis of these materials without the use of water or the introduction of other possible contaminants.

Abstract: A multicore fiber according to an aspect of the present invention includes a plurality of cores and a cladding surrounding the plurality of the cores. In this multicore fiber, a pair of cores is arranged and disposed on a linear line passed through the center of the cladding, the pair of the cores being adjacent to each other and having refractive indexes varied differently from the cladding to the cores.

Abstract: A device for converting transverse spatial profile of intensity of a light beam, using a microstructured optical fiber. Transverse dimensions of the fiber vary longitudinally and both its ends have opto-geometrical parameters such that at the wavelength of the beam the fiber has a fundamental mode having two different profile shapes at its two ends. Thus by introducing the beam with one of the profiles through one of the two ends, the beam emerges through the other end with the other profile, whose shape is different from that of the profile of the introduced beam.

Abstract: A multicore fiber includes a plurality of cores and a cladding that encloses the plurality of the cores. The plurality of the cores is arranged and disposed on a linear line passed through the center of the cladding. A difference in the cutoff wavelength between an outer core located at the outermost position and an inner core located next to the outer core is set at a wavelength of 100 nm or less.

Abstract: An undersea long-haul transmission system includes an optical fiber transmission span and a coherent detection and digital signal processing module for providing dispersion compensation. The transmission span includes at least one fiber pair comprising substantially equal lengths of a positive-dispersion first fiber and a negative-dispersion second fiber that are configured to provide a signal output at transmission distances greater than 10,000 km, in which the combined accumulated dispersion across the operating bandwidth does not exceed the dispersion-compensating capacity of the coherent detection and digital signal processing module. Further described is a fiber for use in an undersea long-haul transmission span. At a transmission wavelength of 1550 nm, the fiber has a dispersion coefficient in the range of ?16 to ?25 ps/nm·km, and a dispersion slope in the range of 0.04 to 0.02 ps/nm2·km.

Abstract: The present invention relates to a GI-type multi-mode optical fiber in which the outer diameter of the core is 47.5 to 52.5 ?m or 60 to 65 ?m, or to a bend resistant multi-mode optical fiber provided with resistance against property fluctuation caused by the bending of the multi-mode optical fiber by providing a trench portion having a low refractive index at the outer periphery of the core. In the multi-mode optical fiber, both the maximum tensile stress and the maximum compressive stress in the optical axis direction remaining in the core are 50 MPa or less.

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: 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: A chemical sensor is provided. The sensor includes at least one lightguiding element having an optical core. The lightguiding element comprises a layer of graphene situated in sufficient proximity to the core to exhibit evanescent wave absorption of optical energy in at least one optical mode guided in the core.

Abstract: The present teachings are generally directed to devices and methods for triplet photons generations, and in particular to on-chip integrated sources for generating direct triplet entangled photons.

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 22.5-27.5 ?m; refractive indexes being a gradient-graded refractive index distribution with a distribution exponent ? in a range of 1.99-2.06; and a maximum relative refractive index difference (RRID) ?1% max in a range of 0.9%-1.3%. 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 25.5-34.5 ?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 30.5-49.5 ?m, and an RRID ?3% in a range of ?0.01%-0.01%. The outer cladding has a radius in a range of 61.5-63.5 ?m, and an RRID ?4% is in a range of ?0.20%-0.30%.

Abstract: An optical fiber is provided that includes a fiber configured to transmit optical data in a plurality of modes or in a single mode; a core region in the fiber that comprises fluorine-doped silica; and a cladding in the fiber that surrounds the core region and that comprises fluorine-doped silica. The core region has a graded refractive index profile with an alpha of about 0.5 to 5. The core of the fiber may be set with a radius of approximately 6 to 50 microns. The cladding may also comprise one or a plurality of layers, including trench or moat regions of a relatively lower refractive index. Still further, an inner cladding may be doped with fluorine at a concentration greater than that in the core region. An outer cladding can comprise silica with fluorine at a concentration below or equal to that in the inner cladding.

Abstract: High aspect ratio core optical fiber designs, which could be semi-guiding, including a core region having a first refractive index and a high aspect ratio elongated cross-section along a slow axis direction, are described. An internal cladding having a second refractive index sandwiches the core and acts as a fast-axis signal cladding. The core has an edge region at both of its short edges that is in contract with edge-cladding regions having a barbell shape. The refractive index of the core regions, the refractive index of the internal claddings, and the refractive index of the edge-cladding regions, are selected so as to maximize the optical power of a lowest-order mode propagating in the fiber core, and to minimize the optical power of the next-order modes in the fiber core. A process to fabricate such a high aspect ratio core fiber is also provided.

Abstract: A large mode field active optical fiber and manufacture method thereof is provided. The large mode field active optical fiber is formed by drawing a fiber core (1), a quartz glass internal cladding (2), a quartz glass outer cladding (3), and a coating (4). The quartz glass internal cladding (2), the quartz glass outer cladding (3), and the coating (4) are sequentially coated on the outer surface of the fiber core (1). The fiber core (1) is formed by depositing, melting, and shrinking the tetrachlorosilane doped with rare earth ions in a quartz glass tube. The refractive index of the fiber core (1) is a graded refractive index, and the section parameter a thereof is 1???3. The appearance of the quartz glass inner cladding (2) is regular multi-prism shaped.

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: 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 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 gradient-graded refractive index distribution with a distribution exponent a 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: An optical fiber link that utilizes concatenated primary and compensating multimode optical fibers is disclosed. The primary optical fiber has a first relative refractive index profile with a first alpha value ?40 of about 2.1 that provides for a minimum amount of intermodal dispersion of guided modes at a peak wavelength ?P40 in the range from 840 nm to 860 nm, and has a first bandwidth BW40 of 2 GHz·km or greater. The compensating optical fiber has a second relative refractive index profile with a second alpha value ?60, and wherein ?0.9?(?60??40)??0.1, and a peak wavelength ?P60 greater than 880 nm. The optical fiber link has improved bandwidth and data rates for first and second optical signals within first and second wavelength ranges, respectively.

Abstract: One exemplary multimode optical fiber includes a graded index glass core having a diameter in the range of 41 microns to 80 microns, a graded index having an alpha less than 2.04 and a maximum relative refractive index in the range between 0.6% and 1.8%. The cladding includes a depressed-index annular portion. The fiber has an overfilled bandwidth greater than 2.5 GHz-km at at least one wavelength between 1200 nm and 1700 nm.

Abstract: The present invention relates to a multimode optical fiber having a structure for stably reducing eccentricity relative to an insert hole of a connector ferrule to be mounted at an end thereof, wherein a fiber outer diameter of the multimode optical fiber along its longitudinal direction varies periodically in a range of ±0.5 ?m with respect to a target fiber outer diameter.

Abstract: Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of ?0.1?????0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive.

Abstract: Embodiments of auto-cladded optical fibers are described. The fibers may have a refractive index profile having a small relative refractive index change. For example, the fiber may include an auto-cladded structure having, e.g., a trough or gradient in the refractive index profile. A beam of light propagating in the fiber may be guided, at least in part, with the auto-cladded structure. In some embodiments, the optical fiber may be all glass. In some embodiments, the optical fiber may include a large-core or an ultra large-core.

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: A few mode optical fiber comprising: a Ge-free core having an effective area Aeff of LP01 mode wherein 120 ?m2<Aeff<1000 ?m2 at 1550 nm, and a refractive index profile selected such that the core is capable of supporting the propagation and transmission of an optical signal with X number of LP modes at 1550 nm, X is an integer and 1<X?20, maximum refractive index delta of the core, ?0, wherein ?0.5%??0?0.08%; and, an annular cladding surrounding the core having a low index ring with a minimum refractive index delta ?rMIN, ?rMIN<?0 and ?rMIN??0.3 relative to pure SiO2, an outer cladding with a refractive index delta ?Outer-Clad, such that ?Outer-Clad>?rMIN; and |?0??Outer-Clad|>0.05%, the relative refractive index profile of the optical fiber is selected to provide attenuation of <0.18 dB/km at the 1550 nm, and LP11 cut off wavelength >1600 nm.

Abstract: The disclosure is directed to an all glass method that frustrates the internal reflection on the outside diameter of an optical fiber's glass cladding thus allowing the light to be directed to a light absorbing material/ medium and allowing the desired light in the core of the fiber to be preserved with no loss. The frustration is achieved by having at least one glass frustrater in glass-to-glass contact with the outermost cladding layer of the optical fiber. The glass frustrater is made of a glass that has a glass transition point lower that both the core and cladding glasses of the fiber. Chalcogenide and phosphate glasses are among the glasses suitable for this application.

Abstract: According to at least one embodiment a graded index multimode fiber comprises: (i) a silica based core co-doped with GeO2 and 1 to 12 mole % P2O5; the core having a dual alpha, ?1 and ?2, where 1.8??1?2.4 and 1.9??2?2.4 at the wavelength (?) range between 840 and 1100 nm; and (ii) a silica based cladding region surrounding the core, wherein the fiber has a numerical aperture NA and 0.185?NA?0.25 (more preferably 0.185?NA?0.23). Preferably, the silica based cladding region surrounding the core has refractive index lower than that of pure silica.

Abstract: An ultra-low loss optical fiber is provided. The ultra-low loss optical fiber includes a core having the maximum refractive index inside an optical fiber, and placed at the central portion of the optical fiber, a trench having the minimum refractive index inside the optical fiber and encompassing the core, and a cladding encompassing the trench. The core includes a first sub-core layer having the maximum refractive index inside the optical fiber, and placed at the center of the optical fiber, a second sub-core layer having a refractive index lower than that of the first sub-core layer and encompassing the first sub-core layer, and a third sub-core layer having a refractive index lower than that of the second sub-core layer and encompassing the second sub-core layer.

Abstract: Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of ?0.1?????0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive.

Abstract: A waveguide including a top cladding layer, the top cladding layer including a material having an index of refraction, n1; an assistant layer, the assistant layer positioned adjacent the top cladding layer, the assistant layer including a material having an index of refraction, n2; a core layer, the core layer positioned adjacent the assistant layer, the core layer including a material having an index of refraction, n3; and a bottom cladding layer, the bottom cladding layer positioned adjacent the core layer, the bottom cladding layer including a material having an index of refraction, n4, wherein n1 is less than both n2 and n3, n3 is greater than n1 and n4, and n4 is less than n3 and n2.

Abstract: The specification describes modified step index and GRaded INdex (GRIN) fibers with low core relative delta (near 0.8%) which have desirable properties for transmission. These lower delta fibers have lower attenuation losses due to reduced Rayleigh scattering, which is desirable to improve performance in multiple mode multiplexing. The fiber designs include optimized raised triangle profiles, and depressed cladding profiles, to support two and four LP modes.

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: Gradient index optical materials are formed by drop by drop dispensing of nanoparticle/monomer suspensions. Refractive index variations are defined by nanoparticle concentrations that can vary in three dimensions. Droplets of differing compositions can be mixed, and droplets or layers or droplets are partially cross-linked by exposure to ultraviolet radiation prior to dispensing additional droplets. Gradient index optical elements such as lenses, prisms, and waveguides can be formed in flexible polymer layers.

Abstract: A multimode optical fiber, and a method of making the fiber, are provided according to the following steps and elements: forming a core preform with a graded refractive index that includes silica and an up-dopant; drawing the core preform into a core cane; forming an inner annular segment preform that includes silica soot and an up-dopant surrounding the core cane; and forming a depressed-index annular segment preform that includes silica soot surrounding the inner annular segment preform. The method also includes the steps: forming an outer annular segment preform that includes silica soot and an up-dopant surrounding the depressed-index annular segment preform; doping the inner, depressed-index and outer annular segment preforms simultaneously or nearly simultaneously with a down-dopant; and consolidating the segment preforms simultaneously or nearly simultaneously into inner, depressed-index and outer annular segments.

Abstract: A core layer (13) of an optical waveguide (1) includes a plurality of core groups (140) disposed so as to mutually intersect on the same plane, each core group (140) being an assembly of a plurality of core portions (14), at least some of which are arranged in parallel, and side cladding portions (15) provided so as to adjoin the side surfaces of each core portion (14). A transverse cross-section of the optical waveguide (1) includes a high refractive index region (WH) in a position corresponding with each core portion (14) and having a relatively high refractive index, and a low refractive index region (WL) in a position corresponding with each side cladding portion (15) and having a lower refractive index than the high refractive index region (WH), and a refractive index distribution is formed in which the refractive index varies continuously across the entire distribution.

Abstract: The invention relates to a fiber structure (700), which has one or more refractive index disturbances (750, 760) outside a fiber core (710) for discriminating one or more high order modes in the fiber structure. The invention also relates to a method for discriminating one or more high order modes, an arrangement having the high order modes discriminating fiber structure, and a device having the high order mode discriminating fiber structure.

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: In one embodiment, an apparatus may include a first capillary component. A second capillary component may be disposed outside of the first capillary component and may have an inner surface, wherein a portion of the inner surface may be heat-fused to an outer surface of the first capillary component. The apparatus may also include a portion of an optical fiber disposed inside of the first capillary component and the portion of the optical fiber can have an outer surface. A portion of the outer surface of the optical fiber may be heat-fused to an inner surface of the first capillary component. The optical fiber may have a distal surface configured to reflect electromagnetic radiation propagated along a longitudinal axis of a distal end portion of the optical fiber in a lateral direction through the inner surface of the first capillary component and the inner surface of the second capillary component.

Abstract: The invention relates to a mode filter for reducing higher-order modes, with an optical fibre (1), which has a core (2) and a cladding (3) surrounding the latter, wherein the cladding (3) and core (2) have refractive indices that differ from one another. In order to develop an alternative to the prior art, the mode filter according to the invention is designed in such a manner that the fibre (1) has, in a transition region (4) between core (2) and cladding (3), at least one local refractive index modification region (5) which is arranged in the radially outer region of the core (2) and extends into the region of the cladding (3).

Abstract: A mode filter for eliminating the propagation of higher-order modes along a section of optical multimode fiber comprises a graded index (GRIN) lens, preferably of a quarter-pitch length, and a pinhole element in the form of a small core fiber. This configuration creates a Fourier spatial filter assembly that removes higher order modes propagating along an optical fiber while capturing the fundamental mode of the optical signal. A section of GRIN fiber is preferably used as the lens, with the small core fiber disposed at the output of the GRIN fiber lens to collect substantially only the on-axis fundamental mode of the optical signal. Since the higher order modes are shifted away from the origin by the GRIN fiber lens, only the fundamental mode signal is captured by the small core 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: 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.