Abstract: In some embodiments, a method for processing an optical fiber includes: drawing an optical fiber through a draw furnace, conveying the optical fiber through a flame reheating device downstream from the draw furnace, wherein the flame reheating device comprises one or more burners each comprising: a body having a top surface and an opposing bottom surface, an opening within the body extending from the top surface through the body to the bottom surface, wherein the optical fiber passes through the opening, and one or more gas outlets within the body; and igniting a flammable gas provided by the one or more gas outlets to form a flame encircling the optical fiber passing through the opening, wherein the flame heats the optical fiber by at least 100 degrees Celsius at a heating rate exceeding 10,000 degrees Celsius/second.

Abstract: A passive optical network includes a central office providing subscriber signals; a fiber distribution hub including an optical power splitter and a termination field; and a drop terminal. Distribution fibers have first ends coupled to output ports of a drop terminal and second ends coupled to the termination field. A remote unit of a DAS is retrofitted to the network by routing a second feeder cable from a base station to the hub and coupling one the distribution fibers to the second feeder cable. The remote unit is plugged into the corresponding drop terminal port, for example, with a cable arrangement having a sealed wave division multiplexer.

Abstract: A loss-based wavelength meter includes a first photodiode configured to measure power of monochromatic light; and a loss section having a monotonic wavelength dependency, wherein a wavelength of the monochromatic light is determined based on measurements of the first photodiode after the monochromatic light has gone through the loss section. This provides a compact implementation that may be used in integrated optics devices using silicon photonics as well as other embodiments.

Abstract: An optical combiner 3 includes a plurality of incoming optical fibers 10, an outgoing optical fiber 20, and a plurality of bridge fibers 60, 50 provided between the plurality of incoming optical fibers 10 and the outgoing optical fiber 20, the plurality of bridge fibers 60, 50 being optically coupled to each other. In the bridge fibers 60, 50, a ratio of the outer diameter of a core 61, 51 to the outer diameter of a cladding 62, 52 is smaller in a bridge fiber located more apart from the incoming optical fiber 10.

Abstract: A preform manufacturing method of the present invention has a hole forming step of forming a plurality of holes in a glass body to produce a glass pipe, and a heating integration step of heating the glass pipe with core rods including core portions being inserted in the respective holes, thereby to implement integration of the core rods and the glass pipe. In the hole forming step, a peripheral hole out of the holes to be formed in the glass body is formed at a position determined in consideration of positional variation of the core portion before and after the integration.

Abstract: The rotary connector is intended for use in the field of fiber optic communication and information transfer. The rotary optical cable connector includes a housing, in which two units with guide sleeves are arranged opposite one another, each having the ends of optical cables fastened therein. One of the units is able to rotate, and the other is fixed. A prism is situated between the guide sleeves, and retainers in the form of rods with a cruciform cross-section are secured in the sleeves. The optical cables are disposed in the recesses in the aforesaid retainers and the ends of the cables line up with gradient-index lenses. The rotary connector transmits four rotating light beams with minimal loss.

Abstract: A bridge fiber includes a core layer 31 and an outer layer 32 which has an index of refraction higher than that of the core layer 31 and covers the outer peripheral surface of the core layer 31. The outer layer 32 is surrounded by a substance such as the atmosphere having an index of refraction lower than an index of refraction n2 of the outer layer 32. An area AR1 of the outer layer 32 at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers, while an area AR2 of the core layer 31 at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber 40.

Abstract: A fibre coupler is provided, which includes a tubular enveloping structure and several optical fibres arranged in the enveloping structure, each of which has a fibre core and a fibre cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fibre core to the diameter of the fibre cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fibre to the diameter of the fibre core, increases in the first direction for each optical fibre.

Abstract: Provided is a method of producing a preform 10P for a coupled multi-core fiber including: an arranging process P1 for arranging a plurality of core glass bodies 11R and a clad glass body 12R in such a way that the plurality of core glass bodies 11R are surrounded by the clad glass body 12R; and a collapsing process P2 for collapsing a gap between the core glass bodies 11R and the clad glass body 12R, wherein the respective core glass bodies 11R have outer regions 16 having a predetermined thickness from the periphery surfaces and made of silica glass undoped with germanium, and the clad glass body 12R is made of silica glass having a refractive index lower than a refractive index of the outer regions of the core glass bodies 11R.

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

Abstract: An novel fiber pump signal combiner is disclosed in which a fiber bundle array is coupled to a double-clad fiber with a taper section that is formed by etching a tapered outer surface into the cladding of a fiber rod to produce a high quality tapered outer surface free of defects with an inner core that has a constant diameter.

Abstract: An electronic device includes a housing, a light emitting module, a light sensor and a lens. The light emitting module is disposed inside the housing and configured to emit a light out of the housing. The light sensor is disposed inside the housing and configured to receive an environmental light from outside of the housing. The lens, coupled with the housing, includes a first transparent portion, a second transparent portion and an opaque portion. The first transparent portion allows the light to be emitted out of the housing. The second transparent portion allows the environmental light to pass through, so that the light sensor receives the environmental light. The opaque portion is disposed between the first transparent portion and the second transparent portion. The first transparent portion, the second transparent portion and the opaque portion are integrated into a whole and made of the same material.

Abstract: A plurality of clad rods, and a clad tube, an arrangement process for arranging the plurality of core rods and the plurality of clad rods in a tube of the clad tube, in a state in which distances between center axes of the adjacent core rods become equal to each other and a state in which parts of outer circumferential surfaces in the adjacent rods contact, and an integration process for integrating the clad tube and the plurality of core rods and the plurality of clad rods arranged in the tube, wherein a ratio of a total cross-sectional area of a direction orthogonal to a length direction in the plurality of core rods and the plurality of clad rods with respect to an internal cross-sectional area of the tube of a direction orthogonal to a length direction in the clad tube is 0.84 or more.

Abstract: The present invention provides a method for making a multicore large diameter optical waveguide having a cross-section of at least about 0.3 millimeters, two or more inner cores, a cladding surrounding the two or more inner cores, and one or more side holes for reducing the bulk modulus of compressibility and maintaining the anti-buckling strength of the large diameter optical waveguide. The method features the steps of: assembling a preform for drawing a multicore large diameter optical waveguide having a cross-section of at least about 0.3 millimeters, by providing an outer tube having a cross-section of at least about 0.3 millimeters and arranging two or more preform elements in relation to the outer tube; heating the preform; and drawing the large diameter optical waveguide from the heated preform. In one embodiment, the method also includes the step of arranging at least one inner tube inside the outer tube.

Abstract: Side emitting glass elements are provided that include a plurality of light guiding elements, which are inseparably connected to one another at their outer circumferential surfaces, and at least one scattering element. The scattering element is inseparably connected to the outer circumferential surface of at least one light guiding element. The light guiding elements have at least one glass with a refractive index n1, wherein the individual light guiding elements are not enclosed by a cladding. A phase boundary is present between the light guiding elements through which the guided light can pass and to reach the scattering element.

Abstract: Fiber optic devices, methods for producing same, and uses of such optical devices are provided. The method includes combining light conducting rods to form bundles in accordance with predefined rules with respect to a cross-sectional area and number thereof in relation to a surrounding sheath, and are subjected to a drawing process. The strong fiber rod produced by the drawing process has an approximately hexagonal outer shape, and due to the drawing process the light conducting rods also have an approximately hexagonal outer contour. Thereby, a high packing density of about 99% is achieved in the fiber rod. Through a further process sequence of bundling and drawing these fiber rods, high-resolution multi-fiber rods are produced that include several thousand light conducting rods, the diameter of an individual light conducting rod included therein being less than 100 ?m.

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

Abstract: A fiber optic assembly includes first and second fiber optic ribbons and a splice protector. Each of the first and second fiber optic ribbons includes a plurality of optical fibers coupled in a substantially flat arrangement, where the optical fibers are aligned side-by-side with one another. The optical fibers of the first ribbon are fusion spliced with the optical fibers of the second ribbon such that the spliced ribbons at the splice have a common lengthwise axis, widthwise axis orthogonal to the lengthwise axis, and thickness axis orthogonal to the lengthwise and widthwise axes. The splice protector supports the optical fibers of the first and second fiber optic ribbons that are spliced to one another at the splice. The splice protector includes an ultra-violet light (UV-) curable adhesive that provides a flexible support for the splice, and is at least half as flexible when cured over the splice as the first and second ribbons in bending about the widthwise axis.

Abstract: Methods for making active laser fibers include the production of an optical fiber with disturbed (or deviated) cylindrical symmetry on the glass surface of the fiber. The methods include a preform containing a central core made of glass. In one embodiment, the preform is circular and surrounded by additional glass rods and an outer glass jacket tube. In a first alternative embodiment, this preform is merged during fiber drawing. In a second alternative embodiment, the preform merged in a process forming a compact glass body with disturbed cylindrical symmetry. This compact preform is drawn into a fiber under conditions maintaining the disturbed cylindrical symmetry.

Abstract: An optical transmission system includes: a multi-core optical fiber having a plurality of core portions. Signal light beams having wavelengths different from each other are caused to be input to adjacent core portions of the plurality of core portions. The adjacent core portions are the most adjacent to each other in the multi-core optical fiber.

Abstract: A multi-core optical fiber includes: a plurality of core portions; and a cladding portion positioned so as to surround each of the core portions, wherein each core portion includes a center core portion that has a refractive index greater than that of the cladding portion, a second core portion that is formed so as to surround the center core portion and that has a refractive index less than that of the center core portion, and a depressed portion that is formed so as to surround the second core portion and that has a refractive index less than those of the second core portion and the cladding portion, and an interval distance between the adjacent core portions is set such that optical cross-talk between the core portions for a total length of the multi-core optical fiber is equal to or less than ?30 dB at a wavelength of 1.55 ?m.

Abstract: A method and an apparatus for making an optical fiber preform comprising the steps of (i) depositing a plurality of rods are deposited into an inner cavity of an apparatus; (ii) depositing particulate glass material in the inner cavity between the rods and the inner wall; and (iii) applying pressure against the particulate glass material to pressurize the particulate glass material against the plurality of rods.

Abstract: A multi-core optical fiber which has a plurality of core portions arranged separately from one another in a cross-section perpendicular to a longitudinal direction, and a cladding portion located around the core portions, the multi-core optical fiber comprises a cylindrical portion of which diameter is even, and a reverse-tapered portion gradually expanding toward at least one edge in the longitudinal direction, wherein a gap between each adjacent ones of the core portions in the reverse-tapered portion is greater than that in the cylindrical portion.

Abstract: The present invention, even in the case where the size of a preform itself is increased, enables production of a multi-core optical fiber in which cores are arranged with high accuracy. A plurality of core members each being rod-like are fixed by an array fixing member while a relative positional relation of the plurality of core members is fixed, and the plurality of core members and a cladding member are integrated into one piece, and thus a preform is obtained. By drawing the obtained preform, a multi-core optical fiber in which core arrangement is controlled with high accuracy is obtained.

Abstract: A method of manufacturing microchannel plate according to an embodiment of the present invention includes: a first step of fabricating a multifiber having a polygonal cross-section by bundling a plurality of fibers; a second step of fabricating a microchannel plate base material by use of a plurality of the multifibers; and a third step of fabricating a microchannel plate out of the microchannel plate base material. The plurality of fibers include: a first fiber whose predetermined-thickness outer circumferential part surrounding a center part including a core is formed of a predetermined-component glass material; and a second fiber whose both center part including a core and outer circumferential part surrounding the same are formed of the predetermined-component glass material. The second fiber is arranged at, at least, one corner of a polygonal cross-section of the multifiber.

Abstract: A method of manufacturing a photonic band gap fiber base material includes: a forming step of continuously forming a columnar core glass body 10 and a clad glass body 20 which coats the core glass body to obtain an intermediate base material 110; a hole making step of making holes 30 in the clad glass body 20; an insertion step of inserting in the holes 30 a plurality of bilayer glass rods 40 in which an outer layer 42 which has the same refractive index as the clad glass body coats high refractive index portions 41 having a higher refractive index than a refractive index of the clad glass body 20; and a heating step of heating the intermediate base material 110 and integrating the intermediate base material 110 and the bilayer glass rods 40.

Abstract: Provided is a method of producing a preform 10P for a coupled multi-core fiber including: an arranging process P1 for arranging a plurality of core glass bodies 11R and a clad glass body 12R in such a way that the plurality of core glass bodies 11R are surrounded by the clad glass body 12R; and a collapsing process P2 for collapsing a gap between the core glass bodies 11R and the clad glass body 12R, wherein the respective core glass bodies 11R have outer regions 16 having a predetermined thickness from the periphery surfaces and made of silica glass undoped with germanium, and the clad glass body 12R is made of silica glass having a refractive index lower than a refractive index of the outer regions of the core glass bodies 11R.

Abstract: A deterministic methodology is provided for designing optical fibers that support field-flattened, ring-like higher order modes. The effective and group indices of its modes can be tuned by adjusting the widths of the guide's field-flattened layers or the average index of certain groups of layers. The approach outlined here provides a path to designing fibers that simultaneously have large mode areas and large separations between the propagation constants of its modes.

Abstract: A connector component for optical fibers has good dimensional accuracy and parallelism. The connector component includes a base material. The base material is provided with at least two holes for inserting and fixing optical fibers therein. The base material is made of quartz glass. Inner components are arranged for forming holes for inserting optical fibers in a die for forming an outer form of the connector component with a dimensional accuracy equal to or less than 2 ?m. Slurry is poured into the die, the slurry including quartz powder, a resin binder, a dispersant, water and a curing agent. The poured slurry is cured and heated under vacuum so as to vitrify the cured slurry to obtain the quartz glass.

Abstract: A method of incorporating within a glass optical waveguide a material of interest having a property of interest that would be neutralized by exposure to molten glass includes combining pieces of a light-transmissive first glass with the material of interest. The combined first glass and material of interest are shaped within a container and heated to a temperature sufficiently high to cause the glass pieces and material of interest to mutually coalesce and form a light-transmissive core rod, but not high enough that the first glass melts and neutralizes the property of interest. A cladding tube is heated and fused about the core rod to define a mono rod. An optical waveguide through which light propagates by internal reflection, and which incorporates the material of interest, is defined when the cladding tube comprises a glass that renders the cladding of lower refractive index than the core rod.

Abstract: A method of manufacturing a holey fiber includes forming a preform and drawing the preform. The forming includes arranging a core rod at a center of a jacket tube and arranging capillary tubes having hollows around the core rod inside the jacket tube. The drawing includes heat melting the preform in a heating furnace while controlling at least one of a gas pressure to be applied to insides of the hollows of the capillary tubes, a temperature of the heating furnace, and a drawing speed, based on a structure of air holes to be formed in a first layer from the core region.

Abstract: A multi-core optical fiber includes: a plurality of core portions; and a cladding portion positioned so as to surround each of the core portions, wherein each core portion includes a center core portion that has a refractive index greater than that of the cladding portion, a second core portion that is formed so as to surround the center core portion and that has a refractive index less than that of the center core portion, and a depressed portion that is formed so as to surround the second core portion and that has a refractive index less than those of the second core portion and the cladding portion, and an interval distance between the adjacent core portions is set such that optical cross-talk between the core portions for a total length of the multi-core optical fiber is equal to or less than ?30 dB at a wavelength of 1.55 ?m.

Abstract: The present invention relates to, for example, a method of easily manufacturing an optical fiber having any refractive index profile with fewer kinds of rods, and an optical fiber is manufactured by preparing a plurality of rods including at least two kinds of rods having different refractive indexes from each other, bundling rods selected from the plurality of rods to construct two or more rod units, producing a preform including a region in which the two or more rod units are combined so as to have a cross-sectional shape having rotational symmetry of order 2 or more, and manufacturing an optical fiber by drawing the preform.

Abstract: According to one embodiment a method of making optical fibers comprises: (i) manufacturing a core cane; (ii) situating a plurality of microstructures selected from rods, air filled tubes and glass filed tubes and placing said microstructures adjacent to the core cane, said microstructures forming no more than 3 layers; (iii) placing the core cane with said adjacent microstructures inside a holding clad tube; and (iv) placing interstitial cladding rods inside the holding (clad) tube, thereby forming an assembly comprising a tube containing a core cane, a plurality of microstructures and interstitial cladding rods. The assembly is then drawn into a microstructured cane and an optical fiber is drawn from the microstructured cane. According to several embodiments, the method of making an optical fiber includes providing at least one air hole and at least one stress rod adjacent to the core.

Abstract: Techniques for ultra-high density connection are disclosed. In one embodiment, an ultra-high density connector includes a bundle of substantially parallel elongate cylindrical elements, where each cylindrical element is substantially in contact with at least one adjacent cylindrical element. Ends of the elongate cylindrical elements are disposed differentially with respect to each other to define a three-dimensional interdigitating mating surface. At least one of the elongate cylindrical elements has an electrically conductive contact positioned to tangentially engage a corresponding electrical contact of a mating connector.

Abstract: A method of making a multi-fiber assembly with irregular hexagonal array, which includes the steps of forming a plurality of primitives each made of a plurality of fibers, said fibers having cylindrical outer surfaces of same diameter and being arranged in an irregular hexagonal array, said irregular hexagonal array having six sides wherein three alternate sides of said primitive are each composed of n fibers and the other three alternate sides of said primitive 11 are each composed of n?1 fibers; and bringing together said primitives in such a way that sides with n fibers of said primitives are in contact with sides with n?1 fibers of other primitive thereby arranging said fibers at a central portion among said primitives in alignment with one another and therefore preventing said fibers at said central portion from squeezing one another.

Abstract: A method for manufacturing a photonic crystal fiber including arranging a spacer formed of two or more spacer parts in a support tube such that the inner wall surface of the support tube has a substantially regular polygonal cross-sectional shape which allows closest packing of a core rod and a plurality of capillaries or the capillaries only; and forming a preform by packing in a support tube the core rod for forming a solid core and the capillaries for forming a cladding, or by providing a core space for forming a hollow core in a support tube and packing in the support tube a plurality of capillaries for forming the cladding; and drawing the preform into a fiber under heating.

Abstract: A multicore optical fibre includes a microstructured cladding material formed from a plurality of cladding elements arranged in an array and each cladding element comprising at least two different materials each having different refractive indices, and a plurality of core elements formed within interstitial regions between adjacent cladding elements. A fibre so formed may have a large number of cores per unit cross-sectional area as compared with prior art fibres, and thus allows the fibre to have relatively short distances between adjacent cores for a given required inter-core isolation. A fibre so formed has utility in many areas requiring high core density, such as inter-chip optical communication, or optical communication between circuit boards.

Abstract: A method of manufacturing a collimator assembly is provided. The method includes placing a first core element within a first center collimator path of a first collimator tube to create a first base-tube couple. A couple cross-section of the first base-tube couple is reduced such that the first base-tube couple becomes a first single-fiber fiber. The first single-fiber fiber is assembled into a collimator group. The first core element is dissolved such that a first hollow fiber is generated.

Abstract: A method of making an article having channels therethrough includes the steps of: providing a ductile structure defining at least one macro-channel, the macro-channel containing a salt; drawing the ductile structure in the axial direction of the at least one macro-channel to reduce diameter of the macro-channel; and contacting the salt with a solvent to dissolve the salt to produce an article having at least one microchannel.

Abstract: Techniques for ultra-high density connection are disclosed. In one embodiment, an ultra-high density connector includes a bundle of substantially parallel elongate cylindrical elements, where each cylindrical element is substantially in contact with at least one adjacent cylindrical element. Ends of the elongate cylindrical elements are disposed differentially with respect to each other to define a three-dimensional interdigitating mating surface. At least one of the elongate cylindrical elements has an electrically conductive contact positioned to tangentially engage a corresponding electrical contact of a mating connector.

Abstract: A method and apparatus are described, which permit a simple, rapid manufacture of an end of an optical fiber bundle. According to the method a metallic sleeve is placed on an end section of the bundle, the end section with the sleeve on it is positioned in a shaping tool without pressing the sleeve and then pressure is exerted on the sleeve exclusively in a radial direction by press jaws of the shaping tool. In the optical fiber bundle made by the method the outer optical fibers (4?) of the optical fiber bundle (1) are embedded at least partially in the sleeve material. The apparatus for making the end of the bundle (1) with the sleeve (10) has a shaping tool (20) including at least two radially movable press jaws (22a-22f) that substantially surround the sleeve (10).

Abstract: An optical cable for communication includes at least one retaining element blocked with respect to the water propagation as well as a process for manufacturing such an optical cable. The optical cable includes, in addition to the retaining element, at least two transmission elements housed within the retaining element and a water swellable yarn housed within the retaining element. The water swellable yarn is selected according to the following equation: V w V TF = k V t + R ( 1 ) in which VW is the volume of the water swellable yarn after swelling upon contact with water; VTF is the total free volume in the retaining element; k is a constant ?180; R is a constant ?1.4; and Vt is the free volume per each transmission element. Advantageously, the optical cable is water-blocked and the water swellable yarn does not induce microbending effects on the transmission elements.

Abstract: A method of fabricating a multichannel plate is provided. The method includes providing a N layers, each layer having an array of wells formed therein. The N layers are aligned and stacked. The stack of N layers are sliced along a first and second line of the array of wells. The first line of the array of wells provides a first surface corresponding to a first array of channel openings of the MCP, and the second line of said array of wells provides a second surface corresponding to a second array of channel openings of the MCP. This method provides several functional benefits compared to conventional methods. These include, but are not limited to: the ability to produce well known and well characterized channels; the ability to produce well known and well characterized periods between channels; the ability to produce channels having any desired secondary electron emission enabling material therein; the ability to fabricate the substrate and/or final MCP of silicon.

Abstract: Techniques for ultra-high density connection are disclosed. In one embodiment, an ultra-high density connector includes a bundle of substantially parallel elongate cylindrical elements, where each cylindrical element is substantially in contact with at least one adjacent cylindrical element. Ends of the elongate cylindrical elements are disposed differentially with respect to each other to define a three-dimensional interdigitating mating surface. At least one of the elongate cylindrical elements has an electrically conductive contact positioned to tangentially engage a corresponding electrical contact of a mating connector.

Abstract: An optical fibre having an axial direction and a cross section perpendicular to the axial direction, the optical fibre having a first light guiding fibre portion with a cladding region with a plurality of spaced apart cladding voids extending longitudinally in the fibre axial direction and a core region bounded by the cladding region, and a solid light transparent fibre portion having a first end facing the first light guiding fibre portion and a second end forming an end face of the optical fibre. The solid light transparent fibre portion provides a hermetic sealing of the cladding voids of the first light guiding fibre portion. A method of producing such an optical fibre and its use, such as an optical fibre connector and an article having a microstructured optical fibre with hermetically sealed end face, are also included.

Abstract: A mesh (36) is placed around a bundle (32) of fused glass fibers. The bundle is then immersed in a leaching bath (44). The ends of the bundle are protected from the bath fluid by furrules (34). Some of the glass of the bundle is leached out, so as to provide a flexible fiber bundle.

Abstract: According to one embodiment a method of making optical fibers comprises: (i) manufacturing a core cane; (ii) situating a plurality of microstructures selected from rods, air filled tubes and glass filed tubes and placing said microstructures adjacent to the core cane, said microstructures forming no more than 3 layers; (iii) placing the core cane with said adjacent microstructures inside a holding clad tube; and (iv) placing interstitial cladding rods inside the holding (clad) tube, thereby forming an assembly comprising a tube containing a core cane, a plurality of microstructures and interstitial cladding rods. The assembly is then drawn into a microstructured cane and an optical fiber is drawn from the microstructured cane. According to several embodiments, the method of making an optical fiber includes providing at least one air hole and at least one stress rod adjacent to the core.

Abstract: A multimode to low-mode optical fiber is constructed by forming a plurality of multimode optical fibers into a fiber bundle. The bundle is then selectively heated and drawn to form a bi-tapered fiber bundle having a central straight portion in which the multimode fibers are fused into a single length of fiber. During the drawing step, measures are taken to provide an aperture extending through the bi-tapered bundle, including the single straight portion of the bundle. An optical fiber having a low-mode or single-mode core is inserted through the aperture into the straight section of the bi-tapered bundle. The bi-tapered bundle and the low-mode core fiber are heated to a temperature at which cladding of the low-mode core fiber fuses to the straight portion of the bi-tapered bundle. The bi-tapered bundle is then cleaved in the straight portion to provide the multimode to low-mode optical fiber combiner. In one example, the multimode fiber bundle is formed around a metal wire before the drawing operation.

Abstract: An optical fiber having a longitudinal direction and a cross-section perpendicular thereto, said fiber in a cross-section comprising: (a) a core region (11) having a refractive index profile with a highest refractive index nc, and (b) a cladding region comprising cladding features (10) having a center-to-center spacing, ?, and a diameter, d, of around 0.4? or larger, wherein nc, ? and d are adapted such that the fiber exhibits zero dispersion wavelength of a fundamental mode in the wavelength range from 1530 nm to 1640 nm; a method of producing such a fiber; and use of such an optical fiber in e.g. an optical communication system, in an optical fiber laser, in an optical fiber amplifier, in an optical fiber Raman amplifier, in a dispersion compensator, in a dispersion and/or dispersion slope compensator.