Abstract: Waveguides are disclosed (and other devices and materials including but not limited to hybrid organic-inorganic coatings, passivation materials, glob top materials, underfill materials, materials for IC and other applications, microlenses and any of a wide variety of optical devices) that benefit by being formed of a novel hybrid organic-inorganic material. In one embodiment of the invention, a method for making a waveguide includes: forming a lower cladding layer on a substrate; forming a core layer after the lower cladding layer; and forming an upper cladding layer after the core layer; wherein the lower cladding layer, core layer and/or upper cladding layer comprises a hybrid organic-inorganic material—that has many desirable properties relating to stability, hydrophobicity, roughness, optical absorbance, polarization dependent loss, among others.

Abstract: The subject invention pertains to a method and apparatus for multiplexing in optical fiber communications. The subject invention relates to a method and apparatus for spatial domain modulation in optical wavelengths. In a specific embodiment, the subject invention relates to a spatial domain multiplexer (SDM) for use with an optical fiber. Preferably, the input channels coupled into the fiber optic cable include collimated laser beams. The techniques of the subject invention can be utilized with single mode and multi mode waveguide structures, for example, single mode and multi mode optical fibers. The subject invention is applicable to step index optical fiber and to graded index optical fiber. Applications of the subject technology can include secure data links, for example, which can modulate data such that if the data is intercepted, the data cannot be interpreted. The subject methods and apparatus can also be used in conjunction with other multiplexing techniques such as time-domain multiplexing.

Abstract: An optical fiber end structure includes an optical fiber having a core end portion and a coating portion extending therefrom, and a glass capillary having a pore. The core end portion of the optical fiber is extended within the pore of the glass capillary. An outer surface of the core end portion of the optical fiber is heat-melted with an inner surface of the pore of the glass capillary to form a transitional layer therebetween such that the core end portion of the optical fiber is coaxially aligned along the axis of the glass capillary. Therefore, it significantly reduces the deviation distance between the core end portion of the optical fiber and the pore of the glass capillary. It not only increases the glass capillary stability and reliability, lower the manufacturing cost, but also improves manufacturing quality and its precision.

Abstract: An optical transmission element comprises optical waveguides embedded into a UV-curing protective layer. The optical waveguides and the UV-curing protective layer are surrounded by a sheath, on which spherical elements are arranged. A conductive layer is applied on the sheath and the spherical elements arranged thereon, said conductive layer having a resistivity. of an order of magnitude of 5·1010 ohms per meter measured at a temperature of between 18 degrees Celsius and 24 degrees Celsius and a relative humidity of 45 percent. In the case of an optical transmission element of this type, electrostatic charging when the optical transmission element is blown into an empty conduit is avoided to the greatest possible extent, such that possible blowing-in lengths within a range of between 500 meters and 1000 meters are obtained.

Abstract: The present invention relates to an optical fiber unit for air blown installation, which includes at least one optical fiber; a buffer layer surrounding the optical fiber and made of radiation curing acrylate; an outer layer surrounding the buffer layer and made of radiation curing acrylate; and a group of solid particles attached to a surface of the outer layer and having an average diameter of 80 to 140 ?m and a specific weight of 2 to 3 g/cc. Thus, there is provided a structurally stable optical fiber unit, which allows easy control of particles while the optical fiber unit is produced, and also has improved installation properties.

Abstract: A plastic optical fiber cable includes: a bare optical fiber including a core made of a poly(methyl methacrylate) or a copolymer including methyl methacrylate as a major component and a cladding layer including, at least in the outermost layer, a layer made of a certain fluorine-containing olefin-based resin; and a coating layer provided on the outer surface thereof. The coating layer includes a protective coating layer, a light blocking coating layer, and a functional coating layer, the layers being provided in the order mentioned from inner side. The protective coating layer is made of a certain resin material. The light blocking coating layer is made of a nylon-based resin including, as a major component, nylon 11 or nylon 12, the nylon-based resin containing monomer and oligomer compounds derived from the nylon-based resin in an amount of a certain range.

Abstract: An optical fiber is provided, which is unlikely to cause interlayer delamination between a glass optical fiber and a primary coating layer even when it is immersed in water. The optical fiber of the present invention includes a glass optical fiber 1 consisting of a core and a cladding, a primary coating layer 2 overlaid on the glass optical fiber, and a secondary coating layer 3 overlaid on the primary coating layer, wherein the relaxation modulus of the secondary coating layer is set at 400 MPa or less.

Abstract: The invention provides a plastic optical fiber cable comprising a plastic optical fiber having a core/clad structure, a light blocking coating layer provided around the plastic optical fiber, and a protective coating layer provided between the outermost layer of the core/clad structure and the light blocking coating layer. The outermost layer of the core/clad structure is made of a fluorine-containing olefin polymer containing at least a tetrafluoroethylene unit, the crystal melting heat of the fluorine-containing olefin polymer being 59 mJ/mg or lower. The light blocking coating layer is made of a resin primarily containing a polyamide resin, the content of polyamide resin-derived monomers and oligomers being 1.5% by weight or lower.

Abstract: An optical fiber part includes an optical fiber having a main fiber, a taper fiber and a small-diameter fiber. The core diameter of the taper fiber decreases along an optical axis. Further, a heat-radiation silicon adhesive that is a highly heat-conductive material having heat conductivity of 4 W/m·K or higher has been applied to the entire area of the outer circumference of the taper fiber and a part of the small-diameter fiber next to the taper fiber. An input end of the optical fiber is connected to a semiconductor laser having an output power of 10 W. Light output from the laser propagates through the optical fiber and output from the output end. A part of light that has propagated through the main fiber and entered the taper fiber is output through the cladding thereof. Heat generated by light output from the cladding is transferred through the heat-radiation silicon adhesive and radiated.

Abstract: Optical fibers and optical transmission systems, which are capable of broadband and large capacity single-mode optical transmission, and have low macrobends are provided. The optical fiber made from pure silica comprising a core region, a cladding region at the circumference of the core region a coating layer made from a resin at the circumference of the cladding region, and having a cutoff wavelength of shorter than 1530 nm, and positive dispersion at 1550 nm, bending loss of less than 10 dB/m at a bending diameter of 20 mm, and an effective core area of 120 ?m2.

Abstract: An optical transmission fiber including a core having a first index of refraction, a cladding material located around the core and having a second index of refraction less than the first index of refraction, a first coating material located around a first portion of the cladding material and having a third index of refraction greater than the second index of refraction, and a second coating material located around a second portion of the cladding material and having a fourth index of refraction less than the second index of refraction.

Abstract: A tension-absorbing cladding layer is formed around a cladding layer, with a refractive index equal to that of a center core region or higher. The center core region has a relative refractive index difference of ?0.1% to 0% with respect to a pure silica glass, a chlorine concentration of wt % to 0.10 wt %, and a fluorine concentration of 0.10 wt % to 0.30 wt %. The tension-absorbing cladding layer has a relative refractive index difference of 0% to 0.05% with respect to the pure silica glass and a chlorine concentration of 0.15 wt % or lower. A ratio of an outer diameter of the tension-absorbing cladding layer to an outer diameter of the cladding layer is 1.10 to 1.40.

Abstract: The present invention relates to an optical fiber accommodated in an optical fiber cable, and more particularly, to an optical fiber which optimizes optical fiber coating resin and color resin and restrains an increase in transmission loss of the optical fiber due to an operating environment and aged deterioration and provides an optical fiber and optical fiber ribbon without any increase of transmission loss irrespective of the operating environment and aged deterioration, and especially when exposed to water or high humidity. The optical fiber is an optical fiber coated with at least two layers of coating resin, wherein the outermost coated coating resin is a colored layer made of color resin and when the optical fiber is immersed in water which is heated to 60° C. for 168 hours, an extraction rate of the coating resin of the optical fiber is set to 1.5 mass percent or below.

Abstract: A double-clad optical fiber includes a core, an inner cladding and an outer cladding of silica-based glass. The core may have a radius of less than about 5 ?m, a first index of refraction n1 and does not contain any active rare-earth dopants. The inner cladding may surround the core and includes a radial thickness of at least about 25 ?m, a numerical aperture of at least about 0.25, and a second index of refraction n2 such that n2<n1. The relative refractive index percent (?%) of the core relative to the inner cladding may be greater than about 0.1%. The outer cladding may surround the inner cladding and include a radial thickness from about 10 ?m to about 50 ?m and a third index of refraction n3 such that n3<n2. The relative refractive index percent (?%) of the inner cladding relative to the outer cladding may be greater than about 1.5%.

Abstract: An optical fiber is made of silica-based glass, and includes a core and a cladding. The optical fiber has a mode field diameter of 5.4 micrometers or larger at a wavelength of 1300 nanometers, transmits light with a wavelength of 1250 nanometers in a single mode, and has a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nanometers when the optical fiber is bent with a curvature radius of 1 millimeter.

Abstract: A waveguide receiving light which propagates through free space is configured with a coupler and delivery fiber. The coupler, including a GREEN or multimode fiber, has a protective coating and so does the delivery fiber. Upon splicing of the coupler to the delivery fiber, the protective coatings of the respective coupler and delivery fiber are spaced apart exposing thus end regions of the respective coupler and fiber. The exposed regions are covered by a light stripper made of material having a refractive index which is substantially the same as or greater than that one of outer claddings. Accordingly, the light stripper minimizes the amount of light capable of coupling into the protective coatings of the respective delivery and coupler fibers enhancing thus a power handling capabilities of the waveguide.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding. The optical fiber having a mode field diameter of 6.5 ?m or larger at a wavelength of 1300 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nm when the optical fiber is bent with a curvature radius of 1.5 mm.

Abstract: The invention relates to high-strength, abrasion-resistant optical fiber cable having a supplemental layer consisting essentially of a liquid crystal polymer (LCP) to enhance the cable's tensile strength and hermetically seal it, and an outermost encasing layer to protect the LCP supplemental layer from damage that could otherwise diminish the tensile strength or destroy the moisture barrier properties of the cable gained by adding the supplemental liquid crystal polymer layer. The encasing layer is preferably a thin layer of a smooth, non-crystalline thermoplastic that can be easily removed with chemicals that do not affect the properties of the supplemental layer so that the supplemental layer can be made accessible for promoting the formation of hermetically sealed interfaces between the cable and other structures. Cross-head extrusion methods for coating optical fibers with LCP and encasing layers are described along with laser and ultrasonic bonding techniques for fabricating hermetic packages.

Abstract: A fiber optic cable includes at least one optic fiber; and a buoyancy modifying coating on the at least one optic fiber, the coating comprising at least one microballoon and a matrix material.

Abstract: A method and apparatus using a gain medium in the form of a multiply clad gain fiber having an erbium-doped core. In some embodiments, aluminum and germanium are added to the silica core to make ?0 longer than the signal wavelength so the signal incurs normal dispersion. Optionally, a large-mode-area core amplifies primarily only one low-order mode because its NA is reduced by lowering the core's index of refraction (e.g., by adding fluorine) and/or by raising the index of the silica inner core (e.g., by adding germanium). Optionally, a thulium-doped region provides substantial loss at the first Raman-gain peak with respect to the signal wavelength but minimal loss at the signal or pump wavelength. Optionally, an inner cladding with a higher NA contains pump light within the outer boundaries of the cladding while allowing pump light to enter the core. In some embodiments, a triple cladding is provided.

Abstract: According to one example of the invention an optical fiber comprises: (i) a core consisting of Al doped silica having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2; (iii) a hermetic carbon based coating surrounding said cladding, said hermetic coating being 300 nm-1000 nm thick; and (iv) a second coating surrounding said hermetic coating, said second coating being 5 ?m to 80 ?m thick.

Abstract: The present invention is directed to a light pipe having an improved structure of prisms. According to one embodiment of the present invention, a hollow light pipe comprises an inner-surface including a linear array of prisms; and a substantially smooth outer-surface, wherein a pitch of prisms in a first region is wider than a pitch of prisms in a second region. According to another embodiment of the present invention, a hollow light pipe comprises a hollow base pipe; and an insertion inserted into the base pipe and having a structured surface including an array of prisms, wherein a pitch of prisms in a first region is wider than a pitch of prisms in a second region.

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 photoactive fiber is provided, as well as a method of fabricating such a fiber. The fiber has a conductive core including a first electrode. An organic layer surrounds and is electrically connected to the first electrode. A transparent second electrode surrounds and is electrically connected to the organic layer. Other layers, such as blocking layers or smoothing layers, may also be incorporated into the fiber. The fiber may be woven into a cloth.

Abstract: An optical waveguide device includes a lower cladding layer, a high refractive index region provided on the lower cladding layer, a pair of cores provided on the lower cladding layer on both sides of the high refractive index region, and an upper cladding layer provided on the high refractive index region and the pair of cores. One of the upper and lower cladding layers has a pair of band-shaped parts disposed between the high refractive index region and the pair of cores.

Abstract: In a waveguide 10 including a substrate 1, a lower clad 2, an upper clad 3, and a core 4, the outline of a cross section perpendicular to the light propagating direction of the core 4 surrounded by the lower clad 2 has a shape curved with respect to the center of the cross section. The separation in the waveguide is thereby prevented, and the reliability of the optical property is enhanced.

Abstract: An optical coupler includes a first optical port, a second optical port, a third optical port, and a fourth optical port. The optical coupler further includes a photonic-bandgap fiber having a cladding, a first core, and a second core. The cladding includes a material with a first refractive index and regions within the cladding. The regions have a second refractive index lower than the first refractive index. The first core is substantially surrounded by the cladding. The first core is optically coupled to the first optical port and to the second optical port. The second core is substantially surrounded by the cladding. The second core is optically coupled to the third optical port and to the fourth optical port. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core such that the first core is optically coupled to the second core. The first core, the second core, or both the first core and the second core is hollow.

Abstract: A colored optical fiber whose transmission loss hardly increases even in a high humidity condition or water-immersed condition is provided. The colored optical fiber according to the present invention is a colored optical fiber having a colored coating layer on a circumference of an optical fiber having at least two coating layers on a circumference of a glass optical fiber, characterized in that a difference in each amount of thermal expansion in an outer diameter direction between the optical fiber and a coating layer obtained by removing the glass optical fiber from the optical fiber in a temperature range from ?100° C. to 100° C. is 1.8 ?m or less.

Abstract: A buffered optical fiber having an excellent pistoning characteristic compared with a conventional one and a manufacturing method thereof are provided. The buffered optical fiber of the present invention is composed of an optical fiber with a primary coating layer and a secondary coating layer provided on a circumference of a glass optical fiber and a tertiary coating layer having thermoplastic polyester elastomer as the main ingredient provided on a circumference of the optical fiber and is characterized in that an outer diameter of the primary coating layer is 180 to 200 ?m, an outer diameter of the secondary coating layer is 350 to 450 ?m and the product of a thickness of the secondary coating layer of the optical fiber and a force of pulling out the glass optical fiber from the optical fiber is 720 N/mm·?m or more.

Abstract: Optical fibers and optical transmission systems, which are capable of broadband and large capacity single-mode optical transmission, and have low macrobends are provided. The optical fiber made from pure silica comprising a core region, a cladding region at the circumference of the core region a coating layer made from a resin at the circumference of the cladding region, and having a cutoff wavelength of shorter than 1530 nm, and positive dispersion at 1550 nm, bending loss of less than 10 dB/m at a bending diameter of 20 mm, and an effective core area of 120 ?m2.

Abstract: A microbend-induced fiber grating is formed from a section of optical fiber configured to exhibit “splitting” between the resonant wavelengths supported by the TE and TM components of the LP1m mode and the resonant wavelength supported by the odd/even HE2m components of the LP1m mode. Since only the TE and TM components are polarization dependent, by splitting and shifting the resonant wavelengths for these modes away from a system-desired wavelength(s) supported by the odd/even HE modes, a polarization insensitive microbend-induced fiber grating can be formed. A fiber core configuration including a central core region, trench and ring is formed to exhibit a large radial gradient in core refractive index profile, with a significantly steep transition between the ring index and the trench index, to provide the desired splitting between the (undesired, polarization sensitive) TE/TM modes and the HE mode.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding, each of the optical fiber having a mode field diameter of 5.5 ?m or larger at a wavelength of 1100 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1100 nm when the optical fiber is bent with a curvature radius of 2 mm.

Abstract: The invention provides a plastic optical fiber cable comprising a plastic optical fiber having a core/clad structure, a light blocking coating layer provided around the plastic optical fiber, and a protective coating layer provided between the outermost layer of the core/clad structure and the light blocking coating layer. The outermost layer of the core/clad structure is made of a fluorine-containing olefin polymer containing at least a tetrafluoroethylene unit, the crystal melting heat of the fluorine-containing olefin polymer being 59 mJ/mg or lower. The light blocking coating layer is made of a resin primarily containing a polyamide resin, the content of polyamide resin-derived monomers and oligomers being 1.5% by weight or lower.

Abstract: An optical transmission fiber is formed to include a relatively low-index, relatively thin outer cladding layer disposed underneath the protective polymer outer coating. Stray light propagating along an inner cladding layer(s) within the fiber will be refracted into the thin outer cladding (by proper selection of refractive index values). The thin dimension of the outer cladding layer allows for the stray light to “leak” into the outer coating in a controlled, gradual manner so as to minimize heating of the coating associated with the presence of stray light. The inventive fiber may also be bent to assist in the movement of stray light into the coating.

Abstract: An optical fiber tape core comprises an optical fiber core assembly and a coating layer formed of silicone rubber and arranged on at least one side of the optical fiber core assembly. In the optical fiber core assembly, plural optical fiber cores two-dimensionally are arranged in parallel with each other. The silicone rubber which forms the coating layer has a hardness of from 20 to 90 and a tensile strength of from 15 to 80 kgf/cm2.

Abstract: A glass-to-meal seal for use in high temperature and high pressure environments is described. The glass-to-metal seals includes an optical fiber having a metallized portion, the metallized portion having an outer dimension; an object having a high strength, corrosion-resistant alloy, the object having an outer surface and an inner surface defining a bore, the bore having a dimension larger than the outer dimension of the metallized portion of the optical fiber; and a hardened solder material disposed between the metallized portion of the optical fiber and the inner surface of the bore, such that a hermetic seal is provided between the metallized portion of the optical fiber and the inner surface of the bore; wherein the solder includes a substance having a melting temperature greater than about 250° C.

Abstract: The present invention provides a curable liquid resin composition which, when cured, exhibits excellent removability from an adjacent coating layer and is suitable for an optical fiber upjacket material. The curable liquid resin optical fiber upjacket composition comprising a urethane (meth)acrylate or a (meth)acrylate oligomer, a reactive diluent, a polymerization initiator, and a polyol compound having a molecular weight of 1500 or more.

Abstract: An optical fiber transmits at least a signal light having a wavelength of 1550 nanometers in a fundamental propagation mode. The optical fiber has, a cutoff wavelength equal to or longer than 1550 nanometers, a wavelength dispersion of 4 ps/nm/km to 7 ps/nm/km in the fundamental propagation mode at the wavelength of 1550 nanometers, a dispersion slope of a positive value equal to or smaller than 0.03 ps/nm2/km in the fundamental propagation mode at the wavelength of 1550 nanometers, an effective core area equal to or larger then 60 ?m2 in the fundamental propagation mode at the wavelength of 1550 nanometers, and a bending loss equal to or smaller than 20 dB/m with a winding of 16 turns at a diameter of 20 millimeters in the fundamental propagation mode at the wavelength of 1550 nanometers.

Abstract: There is disclosed an optical fiber wherein an absolute value of the fourth order dispersion ?4 of fourth derivative ?4 of propagation constant ? with respect to angular frequency ? at a mean zero dispersion wavelength ?0 in an overall length is not more than 5×10?56 s4/m and wherein a fluctuation of a zero dispersion wavelength along a longitudinal direction is not more than ±0.6 nm.

Abstract: An optical cable having a waterproof function includes an optical fiber unit having at least one optical fiber, a tube surrounding the optical fiber unit, and a watertight material layer formed by coating a mixture of watertight material and binder to an inner wall of the tube. This optical cable allows easier fabrication and more convenient use.

Abstract: The invention relates to the field of components with optical fibers and of associated optical fibers. The invention relates, on the one hand, to a component with optical fiber including an at least partly bent optical fiber (2) which successively comprises, from the center to the periphery, an optical core (10) based on silica, an optical cladding (11) based on silica, and a coating (12) having a transparency to infrared radiation larger than 85%. On the other hand, the invention relates to an optical fiber, successively comprising, from the center to the periphery, an optical core (10) based on silica, an optical cladding (11) based on silica, and a coating (12) having a transparency infrared radiation larger than 85%.

Abstract: A coated optical fiber capable of transmitting high-power light, which is an optical fiber having an outer surface coated with a coating material, is characterized in that the coating material is made of a transparent UV curable resin so as to prevent the coating material from absorbing light leaked outside from the optical fiber to generate heat. Further, a light transmitting method is characterized in that a fiber fuse propagation threshold which is a minimal light output required for fiber fuse propagation is obtained and a transmitted light output is controlled so that the transmitted light output becomes smaller than the fiber fuse propagation threshold.

Abstract: An optical fiber, comprising: a core with a first refractive index (n1); a silica based outer cladding surrounding the core, the outer cladding having a refractive index (n), such that the core is substantially surrounded by a gap situated between the core and the outer cladding, the gap containing at least one support structure adjacent to the outer cladding and situated between the outer cladding and the core, wherein the support structure is either hollow or gas filed and is not connected to any other support structure situated within the gap.

Abstract: A large mode area optical fiber is configured to support multiple transverse modes of signal radiation within its core region. The fiber is a hybrid design that includes at least two axial segments having different characteristics. In a first axial segment the transverse refractive index profile inside the core is not radially uniform being characterized by a radial dip in refractive index. The first segment supports more than one transverse mode. In a second axial segment the transverse refractive index profile inside the core is more uniform than that of the first segment. The two segments are adiabatically coupled to one another. Illustratively, the second segment is a terminal portion of the fiber which facilitates coupling to other components. In one embodiment, in the first segment M12>1.0, and in the second segment M22<<M12. In a preferred embodiment, M12>>1.0 and M22˜1.0. In another embodiment, the optical fiber is coupled to a fiber stub.

Abstract: A fiber optic connector having a double-clad specialty optical stub fiber with a deep index core-to-inner-cladding profile and a raised index outer-cladding profile. The double-clad optical stub fiber abuts against a single-clad field optical fiber of the single-mode type to form an interface across which the primary mode traverses without significantly interfering with higher-order modes. The ratio of the radius of the inner cladding to the radius of the core of the stub fiber is less than 6.5:1. The index profile of the refractive index of the inner cladding is deep relative to the refractive index of the core to confine the primary mode within the core. The raised refractive index of the outer-cladding pulls the higher-order modes deeper into that region, reducing interference with the primary mode. The respective core diameters of the field and stub fibers are matched to avoid mode-field diameter mismatch.

Abstract: Microstructured optical fiber and method of making. Glass soot is deposited and then consolidated under conditions which are effective to trap a portion of the consolidation gases in the glass to thereby produce a non-periodic array of voids which may then be used to form a void containing cladding region in an optical fiber. Preferred void producing consolidation gases include nitrogen, argon, CO2, oxygen, chlorine, CF4, CO, SO2 and mixtures thereof.

Abstract: An optical fiber unit for air blown installation includes at least one optical fiber having a core layer and a clad layer, a protective layer coated on the surface of the optical fiber; and protrusions made of polymer resin and formed on the outer circumference of the protective layer in a banded shape. The protrusions may be formed either by supplying polymer resin to the outer circumference of the optical fiber with passing the optical fiber through an extrusion dice in which grooves of a predetermined shape are formed on a hollow inner circumference thereof, or by supplying polymer resin to the outer circumference of the optical fiber through nozzles with moving the optical fiber in a longitudinal direction.

Abstract: Optical waveguide fiber that is bend resistant and single moded at 1260 nm and at higher wavelengths. The optical fiber includes a core and cladding, the cladding having an annular inner region, an annular ring region, and an annular outer region. The annular ring region has a low relative refractive index.

Abstract: Remote sensing in an environment having temperatures greater than 300° C., using an optical fiber having a core (10), a cladding (20), and a metallic protective coating (30) on the cladding to protect a surface of the cladding, the cladding having a diameter greater than 150 ?m, and a thickness of at least 50 ?m. The larger diameter cladding means stress from the metallic protective layer can be reduced, giving lower optical loss and better hydrogen protection. A metal conduit (330) encapsulates the sensing fiber, and a pump evacuates the conduit to reduce hydrogen seepage. Ceramic splice protectors are used. OTDR is used to determine differential loss at different locations along the fiber. A reflective element at the far-end of the fiber eases calibration.

Abstract: Disclosed is an optical fiber unit for air blown installation, which includes at least one optical fiber; a buffer layer surrounding the optical fiber and made of radiation curing acrylate; an outer layer surrounding the buffer layer and made of radiation curing acrylate; and a group of solid particles attached to a surface of the outer layer and having an average diameter of 80 to 140 mm and a specific weight of 2 to 3 g/cc. Thus, there is provided a structurally stable optical fiber unit, which allows easy control of particles while the optical fiber unit is produced, and also has improved installation properties.