Abstract: Provided is an optical fiber having a W-type refractive-index profile and having a reduced bend loss at a practically used bend radius. The optical fiber of the invention comprises: a core; an inner cladding enclosing the core and having a refractive index smaller than the refractive index of the core; and an outer cladding enclosing the inner cladding and having a refractive index which is smaller than the refractive index of the core and larger than the refractive index of the inner cladding, whereas the bend radius Rt is 25 mm or less when ? ? ? ( R ) ? R is the minimum, the bend loss at the bend radius R being ?(R).

Abstract: An optical fiber for transmitting laser beams includes at least one fiber core, at least one fiber jacket, a sheath encompassing the fiber jacket, an interlayer between the fiber jacket and the sheath, in which the refractive index of the interlayer is lower than a refractive index of the corresponding fiber jacket that is in contact with the interlayer, and an outputting means for outputting leakage radiation from the fiber.

Abstract: According to one embodiment, a display device includes a light source, a light guide, a light extraction unit, and a drive circuit. The light source emits a first light. The light guide has a first end, a second end arranged in a first direction, and a side surface extending in the first direction. The light guide guides the first light from the first end toward the second end. The light extraction unit opposes the side surface, and includes first and second conductive units provided parallel to the side surface. The light extraction unit extracts the first light guided inside the light guide by coming close to the side surface for a state in which a voltage is applied to the first and second conductive units. The drive circuit applies the voltage between the first and second conductive units.

Abstract: A LMA, single-mode optical fiber comprises a core region, an inner cladding region surrounding the core region, and an outer cladding region surrounding the inner cladding region. The inner cladding region is configured to provide bend compensation. In one embodiment the index profile of the inner cladding region is graded with a slope of ?ncore/Rb, where ncore is the refractive index of the core region, Rb is the bend radius, and ?=0.6-1.2. In addition, the inner cladding is annular and the ratio of its outer radius to its inner radius is greater than 2. In a preferred embodiment this ratio is greater than 3. The overall index profile may be symmetric or asymmetric.

Abstract: According to some embodiments a few moded optical fiber includes a glass core structured to provide light amplification at an amplification wavelength and a cladding surrounding the core. According to some embodiments the core of the few moded optical fiber includes a portion that has an average concentration of rare earth dopant which is lower by at least 30%, and preferably by at least 50%, than the average concentration of the rare earth dopant at another portion of the core that is situated further from the core center.

Abstract: An optical fiber (1) includes (i) an inner core (111) whose refractive index distribution has an ? profile, (ii) an outer core (112) which surrounds the inner core (111), and (iii) a clad (12) which surrounds the outer core (112). In the optical fiber (1), Rd is set to not less than 0.15, where Rd is a ratio of a refractive index difference between the outer core (112) and the clad (12) to a refractive index difference between a center part of the inner core (111) and the clad (12).

Abstract: A broadband spectral power generator in a multimode optical fiber utilizes a standard multimode fiber that is coiled. A plate is placed on the coiled fiber and a force is applied to compresses the coiled fiber and thereby increase the interactions between the compressed windings and induce modal mixing and birefringence in the fiber. In addition, the compression causes additional non-linear processes to be excited and occur in the compressed fiber coil to generate more broadband light. This allows for better “mixing” of the spatial beam in the multimode fiber coil and allows for the various modes to overlap. The multimode fiber coil is made of silica, silicate, germinate, phosphate, fluoride, chalcogenide, or telluride. The compressed coiled fiber may be driven by a laser providing more than one wavelength output and this greatly increases the amount of nonlinear mixing in the fiber for a greatly enhanced spectral coverage.

Abstract: Various embodiments provide for detection of tapping of an optical signal. In one embodiment an optical fiber includes a cladding region and first and second core regions. The first core region has a first core medium having a first mode-dependent loss (MDL) figure of merit. The second core region has a second core medium having a second different MDL figure of merit. Tapping of the optical signal may be determined to occur when the MDL of the first and second optical signals differs by a predetermined threshold value.

Abstract: A high-powered double cladding (DC) pumped Ytterbium-free L-band Erbium doped fiber amplifier (EDFA) for dense-wavelength-division multiplexing (DWDM) is disclosed. The DC pumped Ytterbium-free L-band EDFA comprises a length of DC Erbium-doped fiber (EDF) that has a low-index, large-diameter core. For some embodiments, the DC-EDF also comprises a trench that is located radially exterior to the cladding, thereby increasing cladding absorption while still effectively maintaining single-mode behavior.

Abstract: Multi-core optical fibers are disclosed herein. According to one embodiment, a multi-core optical fiber includes a common outer cladding formed from silica-based glass and having a cladding index of refraction ncl. At least one single mode core element may be disposed in the common outer cladding. The at least one single mode core element may have a maximum index of refraction n1 sm. In addition, at least one multimode core element may be disposed in the common outer cladding, the at least one multimode core element having a maximum index of refraction n1 mm. The maximum refractive index n1 sm of the at least one single mode core element may be greater than the cladding index of refraction ncl, the maximum refractive index n1 mm of the at least one multi-mode core element may be greater than ncl, and a center-to-center spacing between adjacent core elements is greater than or equal to 25 ?m.

Abstract: Certain embodiments of the invention may include optimized trench-assisted ultra large area (ULA) optical fibers. According to an example embodiment of the invention, a trench-assisted optical fiber, optimized for microbend frontier (MBF) performance is provided. The optical fiber includes a core region having a longitudinal axis, a shelf region surrounding said core region, a cladding region surrounding said shelf region, said core and shelf and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode in said core and shelf regions in the direction of said axis. The optical fiber further includes a core effective area (Aeff) of between 135 ?m2 and about 170 ?m2; a relative effective index difference (Neff) of greater than about 0.08%; a loss at 1550 nm of less than 0.180 dB/km; and a microbend frontier (MBF) distance of less than about 90%.

Abstract: A multi-core fiber includes an even number of six or more of cores and a clad that surrounds the outer circumferential surfaces of the cores. The cores are formed of two types of cores and in which an effective refractive index difference in a fundamental mode is 0.002 or less in a predetermined range or more that the effective refractive index difference in the fundamental mode is varied according to a core pitch. Two types of the cores are alternately and annularly disposed at regular spacings. A difference in the mode field diameter of light propagating through the cores is 1 ?m or less.

Abstract: An optical fiber of the invention satisfies ?core>?ic>?tmax>?tmin, ?0.15%??tmax>?tmin??0.7%, and 0.45?(rtmax?rin)/(rout?rin)?0.9 where the relative refractive index difference of the core is ?core, the relative refractive index difference of the internal cladding coat is ?ic, the relative refractive index difference of a highest refractive index layer in the trench coating is ?tmax, the relative refractive index difference of a lowest refractive index layer in the trench coating is ?tmin, the radius of an internal edge of the trench coating is rin, the radius of an external edge of the trench coating is rout, and the radius of an internal edge of a highest refractive index layer in the trench coating is rtmax and where the relative refractive index differences are based on a refractive index of the outermost cladding coat.

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 radiation-resistant optical fiber includes at least one core and at least one first cladding surrounding the core. The core includes a phosphosilicate matrix, the core being rare-earth doped, the rare earth being chosen from erbium, ytterbium, neodymium, thulium or erbium-ytterbium of thulium-holmium codoped and the core is cerium codoped. Also described is a method for radiation-hardening an optical fiber including the core having a phosphosilicate matrix, the core being rare-earth doped, the rare earth being chosen from erbium, ytterbium, neodymium and thulium, or erbium-ytterbium or thulium-holmium codoped, and including a step of cerium codoping the core of the 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: A trench-assisted, multimode optical fiber includes a central core having an alpha refractive index profile with respect to an outer cladding. The optical fiber also includes an inner cladding, a depressed trench, and an outer cladding. The optical fiber achieves reduced bending losses and a high bandwidth.

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: 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: An easily producible optical fiber preform which is drawn to an optical fiber having a core containing a sufficient concentration of alkali metal is provided. An optical fiber preform 10 is composed of silica-based glass and includes a core portion 20 and a cladding portion 30. The core portion 20 includes a first core portion 21 including a central axis and a second core portion 22 disposed on the perimeter of the first core portion 21. The cladding portion 30 includes a first cladding portion 31 disposed on the perimeter of the second core portion 22 and a second cladding portion 32 disposed on the perimeter of the first cladding portion 31. The core portion 20 contains an alkali metal at an average concentration of 5 atomic ppm or more. The concentration of the OH group in the perimeter portion of the first cladding portion 31 is 200 mol ppm or more.

Abstract: An optical fiber is provided. The optical fiber has a refractive index profile that includes a central core, an inner cladding layer, a trench layer, and an outer cladding layer. A trench layer is provided with a reduced refractive index. The optical fiber has a large effective area without having an increase of a cutoff wavelength, and exhibits low macrobending loss.

Abstract: An optical apparatus comprises: a waveguide substrate, optical cladding formed on the substrate; a waveguide core formed within the cladding, an optically absorptive layer formed within the cladding, and a linearly polarized light source. The waveguide core includes an attenuating segment thereof, and the absorptive layer is formed near the attenuating segment of the core. The core and cladding are arranged to form an optical waveguide that supports a propagating optical mode. The absorptive layer is positioned near the attenuating segment of the core so as to spatially overlap a portion of the optical mode. The extent of the overlap results in a designed level of optical loss per unit distance of propagation of a linearly polarized optical signal along the attenuating segment of the optical core in the optical mode without substantial alteration of the polarization state of the optical signal.

Abstract: A non-zero dispersion shifted optical fiber (NZDSF) includes a central core, an inner cladding, and an outer cladding. The central core has an outer radius r1 and a maximum refractive index difference Dn1 with respect to the outer cladding. The inner cladding includes a first intermediate cladding and a buried trench. The first intermediate cladding has an outer radius r2 and a refractive index difference Dn2 with respect to the outer cladding. The buried trench has an outer radius r3, a width w3, and a negative refractive index difference Dn3 with respect to the outer cladding. In some embodiments, the inner cladding includes a second intermediate cladding having an outer radius r4 and a refractive index difference Dn4 with respect to the outer cladding. For a radius of curvature of 30 millimeters at a wavelength of 1625 nanometers, the optical fiber typically exhibits bending losses of about 0.5 dB/100 turns or less.

Abstract: An optical fiber suitable for high-capacity transmission having a large effective core area, a low bending loss, and capable of single mode operation at 1550 nm is provided. The optical fiber 10 has an effective core area ?175 ?m2 at 1550 nm, a bending loss ?10 dB/m at a bending diameter of 20 mm at 1550 nm, and a cut-off wavelength ?c?1550 nm. The optical fiber has a first core 11 at the center, which has a refractive index higher than that of the cladding 13; and a second core 12 around the first core 11, which has a refractive index lower than that of the cladding 13; a primary medium portion; and secondary medium portions, which have a refractive index lower than that of the primary medium portion and the secondary medium portions have a plurality of first secondary medium portions 15 around the first core 11 and a plurality of second secondary medium portions 16 around the first core 11 and outside of the first secondary medium portions 15.

Abstract: A multicore fiber includes a plurality of core elements; and a clad surrounding an outer periphery surface of each of the core elements, and each of the core elements includes a core, a first clad surrounding the outer periphery surface of the core and a second clad surrounding an outer periphery surface of the first clad, and when a refractive index of the core is n1, a refractive index of the first clad is n2, a refractive index of the second clad is n3 and a refractive index of the clad is n4, all of n1>n2>n3, n1>n4 and n3<n4 are satisfied.

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: 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 polarization-maintaining optical fiber of the present invention includes a core, a pair of stress-applying parts provided on both sides of the core, and a cladding surrounding the core and the stress-applying parts, and is used in a wavelength range of 400 to 680 nm. The diameter of the cladding is 125 ?m, the diameter of the stress-applying part is 33 to 37 ?m, a distance between the pair of stress-applying parts is 8.6 to 15.4 ?m, a relative refractive index difference between the core and the cladding is 0.35 to 0.45%, and a cut-off wavelength is less than or equal to 400 nm.

Abstract: An apparatus and method for compensating for mode-profile distortions caused by bending optical fibers having large mode areas. In various embodiments, the invention micro-structures the index of refraction in the core and surrounding areas of the inner cladding from the inner bend radius to the outer bend radius in a manner that compensates for the index changes that are otherwise induced in the index profile by the geometry and/or stresses to the fiber caused by the bending. Some embodiments of an apparatus and method include a fiber having a plurality of substantially parallel cores, the fiber including a straight section and a curved section; guiding signal light primarily in a second core in the straight section; guiding the signal light from the second core into a first core between the straight section and the curved section; and guiding the signal light primarily in the first core in the curved section.

Abstract: According to some embodiments a single mode fiber includes: a germania doped central core region having outer radius r1 and relative refractive index ?1; and a cladding region comprising (i) a first inner cladding region having an outer radius r2>6 microns and relative refractive index ?2 and 0.3?r1/r2?0.85; and (ii) a second inner cladding region having an outer radius r3>9 microns and comprising a minimum relative refractive index ?3, wherein said second inner cladding region has at least one region with a relative refractive index delta that becomes more negative with increasing radius; and (iii) an outer cladding region surrounding the second inner cladding region and comprising relative refractive index ?4, wherein ?1>?2>?3, ?3<?4.

Abstract: An ytterbium-doped optical fiber includes: a core which contains at least ytterbium, aluminum, and phosphorus; and a cladding which encircles the core, wherein an aluminum oxide equivalent concentration of the aluminum in the core is 0.2 mol % or more, a diphosphorus pentaoxide equivalent concentration of the phosphorus is higher than the aluminum oxide equivalent concentration, and the core either does not contain germanium or contains less than 1.1 mol % of germanium in a germanium dioxide equivalent concentration.

Abstract: The invention relates to a hollow core optical fiber having light guided in a single-mode in the core.

Abstract: There are provided: a core section provided so as to extend in a light-guiding direction in which incident light propagates; a photosensitive layer provided so as to extend in the light-guiding direction and peripherally enclose the core section, the photosensitive layer including a grating formed therein by irradiation of ultraviolet light having a predetermined wavelength; and a first cladding section provided between the core section and the photosensitive layer, the first cladding section having a lower refractive index than the core section and a lower photosensitivity than the photosensitive layer, the photosensitivity being a property in which a refractive index changes in response to irradiation with the ultraviolet light.

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 fiber is provided. The optical fiber includes a core located at the center of the optical fiber and having a maximum refractive index in the optical fiber, and a cladding located at a circumference of the core and having a refractive index lower than that of the core. The core has a structure in which sub-core areas having the refractive index higher than those of adjacent sub-core areas and sub-core areas having the refractive index lower than those of adjacent sub-core areas are alternately repeated.

Abstract: An apparatus and method for coupling light from concentric illuminators into a light source in the form of a surface are disclosed. According to one embodiment, the apparatus comprises a plurality of concentric tubes, each tube including a light diffuser. The apparatus also has a sheet having a first edge with the plurality of concentric tubes placed along the first edge. Each tube of the plurality of concentric tubes diffuses light such that the light emanates in a predetermined pattern along the first edge of the sheet.

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: 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: An optical fiber having both low macrobend loss and low microbend loss. The fiber has a first inner cladding region having an outer radius r2>8 microns and refractive index ?2 and a second outer cladding region surrounding the inner cladding region having refractive index ?4, wherein ?1>?4>?2. The difference between ?4 and ?2 is greater than 0.002 percent. The fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm, and r1/r2 is greater or equal to 0.25.

Abstract: The invention relates to an optical fiber, in particular a laser fiber, containing a doped glass fiber core (1) and cladding (2) around the latter with a refraction index profile which decreases outwards from the fiber core. The optical fiber is distinguished by at least one intermediate layer (3, 4, 5) being disposed between the glass fiber core and the cladding to reduce the mechanical tension therebetween. In one advantageous embodiment, the intermediate layer is doped in such a way as to ensure a stepped mechanical tension distribution between the glass fiber core and the cladding, and is co-doped in such a way as to reduce the refractive index and counteract the refraction index-increasing effect of the intermediate layer doping.

Abstract: An optical fiber includes a central glass core region comprising maximum refractive index delta percent ?1, a first inner annular region surrounding said core comprising refractive index delta percent ?2, a depressed annular region surrounding said inner annular region and comprising ?3 and a third annular region surrounding the depressed annular region comprising refractive index delta percent ?4; wherein the third annular region comprises chlorine an amount greater than 0.2 weight percent in a region which is within 5 microns from the depressed annular region, wherein ?1MAX>?4>?2>?3. The difference between ?4 and ?2 is greater than 0.01 and profile volume, |V3| is at least 50% ??m2.

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 single-mode optical fiber includes a central core, an intermediate cladding, a buried trench, and optical cladding. The central core has an outer radius r1 and a refractive index difference ?n1 relative to the optical cladding. The intermediate cladding has an outer radius r2 and a refractive index difference ?n2 relative to the optical cladding. The buried trench has an outer radius r3 and a refractive index difference ?n3 relative to the optical cladding. The optical fiber typically has an effective area of about 150 ?m2 or greater at a wavelength of 1550 nanometers and exhibits low bending losses.

Abstract: An optical fiber includes a core portion and a cladding portion that is formed around an outer periphery of the core portion and has a refractive index lower than a maximum refractive index of the core portion. As characteristics at a wavelength of 1550 nm, an effective core area in a fundamental propagation mode is 120 ?m2 or larger, an effective core area in a first higher-order propagation mode is 150 ?m2 or larger, an effective core area in a second higher-order propagation mode is 180 ?m2 or larger. An effective refractive index in the second higher-order propagation mode is larger than the refractive index of the cladding portion by 0.0002 or more, and an effective refractive index in a third higher-order propagation mode is less than the refractive index of the cladding portion.

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 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: A low attenuation single mode optical fiber includes a core layer and claddings. The core layer has the relative refractive index difference (RRID) ?1 ranging from ?0.1% to +0.1% and the radius R1 ranging from 4.0 ?m to 6.0 ?m. The claddings have three claddings layers surrounding the core layer. The RRID of the first cladding layer ?2 ranges from ?0.2% to ?0.6%, and the radius R2 thereof ranges from 10 ?m to 22 ?m. The RRID of the second cladding layer ?3 is less than ?2. The RRID and radius of the first cladding layer and the RRID and radius of the second cladding layer satisfy the relationship of: V=(?2??3)×(R3?R2), and the value of V ranges from 0.15% ?m to 0.8% ?m. The third cladding layer is all the layers that closely surround the second cladding layer, and the RRID of each layer is greater than ?3.

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.