Abstract: Radiation curable coatings for use as a Primary Coating for optical fibers, optical fibers coated with said coatings and methods for the preparation of coated optical fibers. A radiation curable Primary Coating composition comprising: an oligomer; a diluent monomer; a photoinitiator; an antioxidant; and an adhesion promoter; wherein said oligomer is the reaction product of: a hydroxyethyl acrylate; an aromatic isocyanate; an aliphatic isocyanate; a polyol; a catalyst; and an inhibitor, wherein said catalyst is an organo bismuth catalyst; wherein said oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; and wherein a cured film of said radiation curable coating composition has a peak tan delta Tg of from about ?25° C. to about ?45° C.; and a modulus of from about 0.50 MPa to about 1.2 MPa.

Abstract: A wet-on-dry process for coating a glass optical fiber with a Radiation Curable Secondary Coating, comprising (a) operating a glass drawing tower to produce a glass optical fiber; (b) applying a radiation curable primary coating composition onto the surface of the optical fiber; (c) applying radiation to effect curing of said radiation curable primary coating composition; (d) applying a Radiation Curable Secondary Coating to the radiation curable primary coating; and (e) applying radiation to effect curing of said Radiation Curable Secondary Coating.

Abstract: An investment instrument based on a range of index values is disclosed that allows investors to take risk positions relative to the size, or length, of the range. The investment instrument has a monetary value that increases as the index value increases within a low range interval of the range, decreases as the index value increases within a high range interval of the range, and is fixed or capped if the index value falls within a middle range interval of the range. Typically, one settlement amount will be zero and the other will be an amount greater than the investment instrument price.

Abstract: Radiation curable coatings for use as a Primary Coating for optical fibers, optical fibers coated with said coatings and processes to coat the optical fiber are described and claimed. The radiation curable coating is a radiation curable Primary Coating composition comprising: an oligomer; a first diluent monomer; a second diluent monomer, a photoinitiator; an antioxidant; and an adhesion promoter; wherein said oligomer is the reaction product of: a hydroxyethyl acrylate; an aromatic isocyanate; an aliphatic isocyanate; a polyol; a catalyst; and an inhibitor, and wherein said oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; wherein a cured film of said radiation curable primary coating composition has a peak tan delta Tg of from about ?25° C. to about ?45° C. and a modulus of from about 0.50 MPa to about 1.2 MPa.

Abstract: Radiation curable coatings for use as a Primary Coating for optical fibers, optical fibers coated with said coatings and methods for the preparation of coated optical fibers. The radiation curable coating comprises at least one (meth)acrylate functional oligomer and a photoinitiator, wherein the urethane-(meth)acrylate oligomer CA/CR comprises (meth)acrylate groups, at least one polyol backbone and urethane groups, wherein about 15% or more of the urethane groups are derived from one or both of 2,4- and 2,6-toluene diisocyanate, wherein at least 15% of the urethane groups are derived from a cyclic or branched aliphatic isocyanate, and wherein said (meth)acrylate functional oligomer has a number average molecular weight of from at least about 4000 g/mol to less than or equal to about 15,000 g/mol; and wherein a cured film of the radiation curable Primary Coating composition has a modulus of less than or equal to about 1.2 MPa.

Abstract: A multi-core optical fiber 1A in which a plurality of cores can easily be identified even in the case where they are symmetrically arranged in its section has seven cores 10 to 16, a visual recognition marker 20, and a shared cladding 30 enclosing the seven cores 10 to 16 and the visual recognition marker 20. The cores 10 to 16, the visual recognition marker 20, and the cladding 30 are respectively made of silica glass as their main element. The cores 10 to 16 and the visual recognition marker 20 extend along the fiber-axis direction. The respective refractive index of the cores 10 to 16 is higher than the refractive index of the cladding 30. The refractive index of the visual recognition marker 20 differs from that of the cladding 30. In the cross-section perpendicular to the fiber-axis, the cores 10 to 16 are arranged such that they have 6-fold rotational symmetry and line symmetry. The visual recognition marker 20 is arranged at a position which breaks such symmetry.

Abstract: There is provided an optical waveguide comprising an optical core having transverse sides, the optical core extending along a curved path; an optical cladding on the transverse sides of the optical core, wherein the distribution of the optical cladding on the transverse sides of the optical core is asymmetric about the centre of the core.

Abstract: An apparatus may include a waveguide. The waveguide may include a distal end surface which may be substantially normal to a centerline of a distal end portion of the waveguide. The apparatus may further include a cover which may be coupled to a portion of the waveguide. The cover may include a portion distal to the distal end surface of the waveguide, and the portion of the cover may be made of a material which may be configured to be removed when exposed to electromagnetic radiation emitted from a portion of the distal end surface of the waveguide.

Abstract: The present invention provides a colored coated optical fiber which hardly has an increase in transmission loss even when immersed in water. A colored coated optical fiber according to one embodiment of the present invention includes a glass optical fiber, a primary coating layer covering the glass optical fiber, a secondary coating layer covering the primary coating layer, and a colored layer covering the secondary coating layer. A ratio of a thermal expansion coefficient of a laminate including the secondary coating layer and the colored layer covering the secondary coating layer to that of the secondary coating layer is 0.98 or more and 1.03 or less. A ratio of a glass transition temperature based on a dynamic viscoelasticity within a temperature range from ?100° C. to 150° C. of the laminate to that of the secondary coating layer is 0.96 or more and 1.03 or less.

Abstract: Various embodiments described herein include rare earth doped glass compositions that may be used in optical fiber and rods having large core sizes. Such optical fibers and rods may be employed in fiber lasers and amplifiers. The index of refraction of the glass may be substantially uniform and may be close to that of silica in some embodiments. Possible advantages to such features include reduction of formation of additional waveguides within the core, which becomes increasingly a problem with larger core sizes.

Abstract: Light diffusing optical fibers and methods for producing light diffusing optical fibers are disclosed. In one embodiment, a light diffusing optical fiber includes a core portion formed from silica glass and comprising a plurality of helical void randomly distributed in the core portion of the optical fiber and wrapped around the long axis of the optical fiber. A pitch of the helical voids may vary along the axial length of the light diffusing optical fiber in order to achieve the desired illumination along the length of the optical fiber. A cladding may surround the core portion. Light guided by the core portion is scattered by the helical voids radially outward, through the cladding, such that the light diffusing optical fiber emits light with a predetermined intensity over an axial length of the light diffusing optical fiber, the light diffusing optical fiber having a scattering induced attenuation loss greater than about 0.2 dB/m at a wavelength of 550 nm.

Abstract: A coated glass fiber 1 comprising a glass fiber 10 and one or more coating layers each composed of an ultraviolet curable resin on the outer circumference of the glass fiber 10, wherein the ultraviolet curable resin constituting at least one of the coating layers is formed of an ultraviolet curable coating material containing a silane coupling agent and a photoacid generator. The coated optical fiber 1 coated optical fiber having a high dynamic fatigue coefficient since adhesion between the surface of the glass fiber and the resin coating layer is satisfactory.

Abstract: Provided is a bend-insensitive optical fiber including a core centered at the optical fiber, a cladding surrounding the core and having a lower refractive index than the core, a coating layer surrounding the cladding, and a region formed in the cladding and having a lower refractive index than the cladding, wherein the coating layer has a multilayered structure and a total outer diameter of 240 ?m or less, and a bend-insensitive optical cable comprising the same.

Abstract: A method of coupling a spliceable optical fiber includes (A) providing the spliceable optical fiber, the spliceable optical fiber including (a) a core region; and (b) a microstructured cladding region. The cladding region surrounds the core region and includes (b1) an inner cladding region having a refractive index formed by inner cladding features arranged in an inner cladding background material with a refractive index n1, the inner cladding features including thermally collapsible holes or voids, and (b2) an outer cladding region with an outer cladding background material with a refractive index n2, the spliceable optical fiber having at least one end. (B) Collapsing the thermally collapsible holes or voids by heating the at least one end of the spliceable optical fiber thereby increasing the refractive index of the inner cladding providing an expanded core. And, (C) coupling the collapsed spliceable optical fiber end to the optical component.

Abstract: A graded index multimode optical fiber comprising: (a) a silica core doped with germania, and at least one co-dopant, comprising one of P2O5 or F or B2O3, the core extending to outermost core radius, r1 and having a dual alpha, ?1; (b) a low index inner cladding surrounding the core and off-set from said core; (c) an outer cladding surrounding and in contact with the inner cladding, such that at least the region of the inner cladding off-set from said core has a lower refractive index than the outer cladding. The center germania concentration at the centerline, CGe1, is greater than or equal to 0, and an outermost germania concentration in the core CGe2, at r1 is greater than or equal to 0. The core has a center co-dopant concentration at the centerline, Cc-d1, greater than or equal to 0, and an outermost co-dopant concentration Cc-d2, at r1, wherein Cc-d2 is greater than or equal to 0.

Abstract: A radiation curable composition is disclosed that includes a curable cross-linker essentially free of urethane and urea functional groups, a curable diluent, and a non-radiation curable component comprising (thio)urethane and/or urea groups. Coated optical fibers having a primary coating formed from this radiation curable composition, as well as optical fiber ribbons that contain the coated optical fibers are disclosed. Methods of making the optical fibers and ribbons are also disclosed.

Abstract: Micromodule breakout cables are constructed to pass selected burn tests while maintaining a desired degree of accessibility and durability. The micromodule cables can be incorporated in data centers and are robust enough to serve as furcation legs while allowing hand accessibility. The cables can incorporate optical fibers with low delta attenuation and can have low skew.

Abstract: The present invention relates to an optical fiber for an SPR sensor, characterized in that the optical fiber is comprised of a core layer and a cladding layer surrounding the core layer, and the cladding layer is doped with metal nanoparticles.

Abstract: The present invention provides an optical fiber in which the transmission loss increase is suppressed even under a high-humidity condition or under a water-immersed condition. A colored optical fiber (22) according to an embodiment of the present invention is a colored optical fiber (22) formed by applying a colored layer to an optical fiber (14) including a glass optical fiber coated with at least a double-layered coating layer of a soft layer and a hard layer, and the ratio of thermal expansion coefficient between the coating layer after the colored layer of the colored optical fiber (22) is applied and the coating layer of the optical fiber (14) before the colored layer is applied is 0.87 or more.

Abstract: The present invention provides a colored coated optical fiber which hardly has an increase in transmission loss even when immersed in water. A colored coated optical fiber according to one embodiment of the present invention includes a glass optical fiber, a primary coating layer covering the glass optical fiber, a secondary coating layer covering the primary coating layer, and a colored layer covering the secondary coating layer. A ratio of a thermal expansion coefficient of a laminate including the secondary coating layer and the colored layer covering the secondary coating layer to that of the secondary coating layer is 0.98 or more and 1.03 or less. A ratio of a glass transition temperature based on a dynamic viscoelasticity within a temperature range from ?100° C. to 150° C. of the laminate to that of the secondary coating layer is 0.96 or more and 1.03 or less.

Abstract: An optical fiber comprising: (i) a multi-mode silica based glass core, said core having a 80-300 ?m diameter and an index of refraction n1; (ii) a cladding surrounding the core, said cladding having a thickness ?20 ?m and index of refraction index of refraction n2<n1, the cladding comprising (a) fluorine doped silica with relative index of refraction delta <0, or (b) a polymer with relative index of refraction delta <0; (iii) a protective coating, the protective coating having a Young's modulus greater than 700 MPa, a thickness ?15 ?m, and an index of refraction index of refraction n3>n2; and (iv) a permanent buffer.

Abstract: A multi-mode optical waveguide fiber including a central core region having an outer radius surrounded by an inner cladding region having an outer radius, the inner cladding region having a lower index of refraction than the central core region, wherein both the central core and inner cladding regions are doped with fluorine, wherein the refractive index profile of the central core region is of the gradient index type and the central core region in the range of r?[0-ra] comprises germanium at a maximum concentration within the range of 0.5 percent by weight to 4.0 percent by weight taken at a given radius, wherein said fiber has an Overfilled Modal Bandwidth >500 MHz·km at a wavelength of 850 nm and 1300 nm, according to IEC 60793-2-10.

Abstract: A multi-core optical fiber includes a plurality of core portions. The diameter of each of the core portions is 12 micrometers or smaller, the relative refractive-index difference of the core portions with respect to the cladding portion is 0.2% or larger, the cut-off wavelength is 1.53 micrometers or smaller, the bending loss at a 1.55-micrometer wavelength is 10 dB/m or smaller, the effective core area at a 1.55-micrometer wavelength is 30 ?m2 or larger, and the cross-talk of light between the core portions is ?35 decibels or smaller.

Abstract: An optical fiber includes a core (1a) having an oblong rectangular or square cross section and made of quartz, a cladding (2) surrounding the core (1a), having a circular outer cross-sectional shape, having a lower refractive index than the core (1a), and made of resin, and a support layer (3) surrounding the cladding (2) and made of quartz.

Abstract: An apparatus may include a waveguide. The waveguide may include a distal end surface which may be substantially normal to a centerline of a distal end portion of the waveguide. The apparatus may further include a cover which may be coupled to a portion of the waveguide. The cover may include a portion distal to the distal end surface of the waveguide, and the portion of the cover may be made of a material which may be configured to be removed when exposed to electromagnetic radiation emitted from a portion of the distal end surface of the waveguide.

Abstract: An embodiment of an apparatus includes an optical fiber for which a complete orthogonal basis of propagating modes at an optical telecommunication frequency includes ones of the propagating modes with different angular momenta. The optical fiber has a tubular optical core and an outer optical cladding in contact with and surrounding the tubular optical core. The tubular optical core has a larger refractive index than the optical cladding. The tubular optical core is configured such that those of the propagating modes whose angular momenta have the lowest magnitude for the propagating modes have substantially the same radial intensity profile.

Abstract: An apparatus includes an optical fiber having a plurality of optical cores therein. Each optical core is located lateral in the optical fiber to the remaining one or more optical cores and is able to support a number of propagating optical modes at telecommunications wavelengths. Each number is less than seventy.

Abstract: In one embodiment, an apparatus includes an optical fiber made of a silica-based material. A proximal end portion of the optical fiber has an outer-layer portion. The proximal end portion can be included in at least a portion of a launch connector configured to receive electromagnetic radiation. The apparatus also includes a component that has a bore therethrough and can be made of a doped silica material. The bore can have an inner-layer portion heat-fused to the outer-layer portion of the optical fiber. The component can also have an index of refraction lower than an index of refraction associated with the outer-layer portion of the optical fiber.

Abstract: A telecommunication cable is equipped with at least one optical fiber coated by a tight buffer layer made from a polymeric material having an ultimate elongation equal to or lower than 100% and an ultimate tensile strength equal to or lower than 10 MPa. The above combination of features of the polymeric material forming the buffer layer provides an optical fiber which is effectively protected during installation operations and during use, and at the same time can be easily stripped by an installer without using any stripping tools, simply by applying a small pressure with his fingertips and a moderate tearing force along the fiber axis.

Abstract: An optical fiber having a core and an outer cladding, the core including from its center outward a central core having a radius and a refractive index difference with respect to the outer cladding, and a depressed inner cladding. The depressed inner cladding includes at least a first portion having a radius and a refractive index difference with respect to the outer cladding, the first portion preferably being adjacent to the central core, and a second portion adjacent to the first portion constituting a depressed trench having a radius, and a refractive index difference with respect to the outer cladding. The first portion of the inner cladding has a refractive index below the refractive index of the outer cladding, and the depressed trench has a refractive index that is lower than the refractive index of the first portion of the depressed inner cladding.

Abstract: An optical fiber having increased mechanical strength is provided. The optical fiber includes an over cladding layer that has a compressive stress of at least 100 MPa.

Abstract: A plastic-cladding optical fiber is provided. The plastic-cladding optical fiber is provided includes: a core layer made of quartz glass; and a cladding layer formed by hardening a curable resin composition over a periphery of the core layer. Adhesion between the core layer and the cladding layer ranges 1.5 g/mm to 4.0 g/mm.

Abstract: The present invention relates to a multi-core optical fiber that can realize suppression of crosstalk on an easy and inexpensive basis. The multi-core optical fiber is provided with a plurality of core portions extending along a central axis of the fiber, a common cladding portion integrally holding the core portions inside, a coating layer surrounding the common cladding portion, and a bend applying portion. The bend applying portion, as an example, is provided on a partial region of an outer periphery of the coating layer and applies bending stress to a glass region.

Abstract: This optical fiber cable is provided with a covering resin including an outermost layer. The outermost layer is formed by a resin composition including: (a) a base resin prepared by adding at least one copolymer selected from an ethylene-vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer to a high density polyethylene; (b) 25 to 90 parts by weight of a phosphate salt with respect to 100 parts by weight of the base resin; and (c) 0.75 to 15 parts by weight of either a silicone dispersed polyethylene or a silicone grafted polyethylene with respect to 100 parts by weight of the base resin.

Abstract: Disclosed is an improved optical fiber possessing a novel coating system. When combined with a bend-insensitive glass fiber, the novel coating system according to the present invention yields an optical fiber having exceptionally low losses. The coating system features (i) a softer primary coating with excellent low-temperature characteristics to protect against microbending in any environment and in the toughest physical situations and, optionally, (ii) a colored secondary coating possessing enhanced color strength and vividness. The secondary coating provides improved ribbon characteristics for structures that are robust, yet easily entered (i.e., separated and stripped). The optical fibers in accordance in the present invention may be incorporated into a reduced-diameter optical-fiber cable that possesses a high fiber count and a high cable fiber density.

Abstract: According to some embodiments the triple-clad optical fiber comprises a core, a first inner cladding, a second inner cladding, and an outer cladding wherein: (i) the core comprises a radius r0 a first index of refraction n0; (ii) the first inner cladding surrounds the core and has a numerical aperture of at least about 0.12, and a second index of refraction n1 such that n1<n0, (iii) the second inner cladding surrounds the first inner cladding a numerical aperture of at least about 0.2, and a second index of refraction n2 such that n2>n1, wherein a relative refractive index percent (?%) of the second cladding relative to the outer cladding is greater 1%; and (iv) the outer cladding surrounds the second inner cladding and has a third index of refraction n3 such that n3<n2, and n3<n1.

Abstract: A process for manufacturing an optical fiber includes: drawing an optical waveguide from a glass preform; applying a layer of a first coating material on the optical waveguide; curing the first coating layer material to obtain a first coating layer; applying a layer of a second coating material onto the first coating layer; applying a layer of colored coating material onto the second coating layer; curing the second coating material and the colored coating material in a single step to obtain a second coating layer superposed on the first coating layer and a colored coating layer superposed on the second coating material layer, the obtained second coating layer having an elastic modulus higher than that of the first coating layer and lower than that of the colored coating layer. An optical fiber and an apparatus for producing it are also provided.

Abstract: The present invention relates to a multi-core optical fiber having a structure to effectively reduce crosstalk between adjacent core regions among a plurality of core regions. The multi-core optical fiber (1) has a leakage reduction portion (50), at least a portion of which is arranged at a position on a straight line connecting adjacent core regions together among a plurality of core regions (10). The leakage reduction portion (50) reduces leakage light in the multi-core optical fiber (1) from each of the core regions (10), thereby effectively reducing crosstalk between adjacent core regions.

Abstract: A multi-core optical fiber 1A in which a plurality of cores can easily be identified even in the case where they are symmetrically arranged in its section has seven cores 10 to 16, a visual recognition marker 20, and a shared cladding 30 enclosing the seven cores 10 to 16 and the visual recognition marker 20. The cores 10 to 16 and the visual recognition marker 20 extend along the fiber-axis direction. The respective refractive index of the cores 10 to 16 is higher than the refractive index of the cladding 30. The refractive index of the visual recognition marker 20 differs from that of the cladding 30. In the cross-section perpendicular to the fiber-axis, the cores 10 to 16 are arranged such that they have 6-fold rotational symmetry and line symmetry. The visual recognition marker 20 is arranged at a position which breaks such symmetry.

Abstract: The present invention embraces a multimode optical fiber that includes a central core having an alpha-index profile, an inner cladding, a depressed trench, and an outer cladding (e.g., an outer optical cladding). Typically, the central core's alpha-index profile has a minimum refractive index at the central core's radius that corresponds to a refractive index difference with respect to the outer cladding. The optical fiber achieves reduced bending losses and a high bandwidth with a reduced cladding effect for high-data-rate applications.

Abstract: A single-mode optical fiber includes a central core, an intermediate cladding, a depressed trench, and an external optical cladding. The central core has a radius r1 and a positive refractive index difference ?n1 with the optical cladding. The intermediate cladding has a radius r2 and a refractive index difference ?n2 with the optical cladding, wherein ?n2 is less than ?n1. The depressed trench has a radius r3 and a negative index difference ?n3 with the optical cladding. At a wavelength of 1310 nanometers, the optical fiber has a mode field diameter (MFD) between 8.6 microns and 9.5 microns and, at a wavelength of 1550 nanometers, the optical fiber has bending losses less than about 0.25×10?3 dB/turn for a radius of curvature of 15 millimeters. At a wavelength of 1260 nanometers, attenuation of the LP11 mode to 19.3 dB is achieved over less than 90 meters of fiber.

Abstract: An optical fiber includes a silica-based glass portion having an outer diameter of less than about 120 ?m. The glass portion comprises a core, an inner cladding and a low index ring. The core comprises an index of refraction n1, and a relative refractive index percent ?1% relative to pure silica glass. The inner cladding surrounds the core and comprises an index of refraction n2, a radial thickness of less than about 40 ?m and a relative refractive index percent ?2% relative to pure silica glass, wherein ?1%>?2% and the difference between ?1% and ?2% is greater than 0.1%. The low index ring surrounds the inner cladding and comprises boron and fluorine, a radial thickness of less than about 20 ?m, an index of refraction n3 and a third relative refractive index percent ?3% relative to pure silica glass, wherein ?2%>?3% and ?3% is less than ?0.5%.

Abstract: A trench optical fiber that stably realizes a small transmission loss includes (1) a core extending in an axial direction while containing an axial center of the fiber, the core having a diameter d1 of 7.0 ?m to 7.4 ?m; (2) a first optical cladding layer surrounding the core and having an outside diameter d2 of 1.67 dl to 2.5 dl; (3) a second optical cladding layer surrounding the first optical cladding layer; and (4) a jacket layer surrounding the second optical cladding layer and containing fluorine having a concentration of 0.06 wt % or higher. A relative refractive index difference ?1 of the core with respect to the jacket layer is 0.31% to 0.37%. A relative refractive index difference ?2 of the first optical cladding layer with respect to the jacket layer is +0.02% or larger and smaller than ?1. A relative refractive index difference ?3 of the second optical cladding layer with respect to the jacket layer is ?0.2% or smaller.

Abstract: Embodiments of the present invention provide a plastic fiber coupler. The plastic fiber coupler includes a bundle of plastic optical fibers (POFs) arranged in a ring-shape; and an optical mixing tube attached to a cross-section of the bundle of POFs. In one embodiment, a cross-section of the optical mixing tube may be coated with a reflective film forming a reflective type plastic fiber coupler; in another embodiment, the optical mixing tube is attached to a second bundle of plastic optical fibers forming a transmissive type plastic fiber coupler.

Abstract: A plastic optical fiber cable includes: a bare plastic optical fiber including a core formed of a polymer containing a methyl methacrylate unit, and a clad layer including a layer formed of a specific fluorine-containing olefin resin at least in the outermost layer; and a coating layer around the bare plastic optical fiber, the coating layer including a light-shielding coating layer formed of a specific nylon resin composition, a functional coating layer (C) and a functional coating layer (D) in this order, where one of the functional coating layer (C) and the functional coating layer (D) is formed of a resin composition (I) containing a polybutylene terephthalate resin as a major component or an ethylene-vinyl alcohol copolymer as a major component; the other is formed of a specific nylon resin composition (II); and a ratio of the thickness of the functional coating layer (C) to the thickness of the functional coating layer (D) is set to fall within a specific range.

Abstract: An optical fiber contact for transmitting moderate-magnitude optical power. The fiber contact includes an optical fiber having an inner core and a surrounding cladding for transmitting the radiation in the core. Additional surrounding layers including so-called buffer and jackets mechanically stabilize the optical fiber. The forward part of the optical fiber contact is surrounded by a transparent tubular member. The tubular member extends a certain length along the outer cylindrical surface of the cladding. There is no heating by power loss radiation, as the power loss radiation is leaving the contact as optical radiation. To disperse radiation propagating within the cladding, the cladding includes a roughening or additional layers of a transparent material. In case of additional layers of transparent material then the outermost layer should be roughened.

Abstract: A large diameter fiber is composed of a multimode optical fiber and provided with a fiber body having a constant diameter in an optical axis direction XA and a tapered section tapered in diameter toward a light exit surface. An adhesive member attaches the large diameter fiber inside a retaining hole of a tubular housing such that an outer circumferential surface of a tapered clad of the tapered section is entirely exposed to air to a predetermined depth from the light exit surface. A light passing space is a ring-like space formed between the exposed outer circumferential surface of the tapered clad and an inner circumferential surface of the tubular housing. Light in the tapered section is output from the light exit surface and partially leaked to the tapered clad. A part of the leaked light is released from the light passing space.

Abstract: The present invention relates to an optical fiber that includes a glass fiber and three or more coatings that encapsulate the glass fiber, where the three or more coatings include a primary coating in contact with said glass fiber, one or more intermediate coatings that surround the primary coating, and a secondary coating that surrounds the intermediate coatings. Both three-coating and four-coating systems are described that afford improve microbend performance.

Abstract: A method of manufacturing an optical fiber includes a first step of drawing an optical fiber preform into a glass fiber and disposing a fiber coating on the outer circumference of the glass fiber to form a parent optical fiber; a second step of cutting the parent optical fiber into a plurality of individual optical fibers; a third step of determining, at, at least, one spot of the parent optical fiber, a failure strength F1 and a failure time T; a fourth step of determining a failure strength F2 of each of the individual optical fibers; and a fifth step of selecting an optical fiber having a failure strength F2 of 5.5 kgf or more from the individual optical fibers cut from the parent optical fiber whose failure strength F1 and failure time T satisfy the inequality T>2.6×10?11×exp(4.736×F1).

Abstract: An optical fiber includes a cladding, a first core, and a second core. At least one of the first core and the second core is hollow and is substantially surrounded by the cladding. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core. The optical fiber includes a defect substantially surrounded by the cladding, the defect increasing a coupling coefficient between the first core and the second core.