Abstract: The present invention provides a glass packing tube for use in fabricating a microchannel plate. The glass tube has a plurality of flat inner surfaces and is used to form a boule including a plurality of optical fibers located in the tube and a plurality of support rods between the first optical fibers and the flat surfaces whereby the tube, fibers and rods are fused together with reduced glass flow.

Abstract: A tapered fiber bundle is formed by first etching the end portions of each fiber within the group so as to remove a selected amount of outer cladding material from each fiber. The assembled, etched fibers are then fused together in conventional fashion to form a fiber bundle. By first etching the fibers to form a “tapered” structure, the core diameter of the tapered fiber bundle remains intact; in the prior art, the tapering process of drawing down the fused collection of fibers would reduce the core diameter. Preferably, the outer cladding of the central single mode fiber is modified to exhibit the same etch rate as the outer cladding layer of the remaining fibers.

Abstract: A method of making a fiberoptic light guide utilizes a hollow glass cladding blackened by chemical reduction. The cladding has a predetermined lead content and is heated to an elevated temperature in an atmosphere of substantially 100% hydrogen gas in a furnace. The blackening step is accomplished before or after a bundle of optic fibers is inserted within the cladding and is drawn to produce a fused fiberoptic rod. The blackening step provides the cladding with a black opaque nature that inhibits the transmission of light transversely through the cladding.

Abstract: A method for forming a multicore fiber laser array includes inserting a plurality of rare-earth doped rods into a corresponding plurality of hollow capillaries, and arranging the resulting plurality of filled capillaries into a preform pattern. The plurality of filled capillaries are collapsed into an initial preform structure, wherein a portion of the material of the capillaries forms an initial inner cladding. The initial preform structure is inserted into a cylinder, wherein the cylinder and the initial preform structure are fused so as to form a final preform structure with a final inner cladding having an increased thickness with respect to the initial inner cladding. At least one flat surface is formed along the length of the final preform structure, and a fiber is simultaneously drawn from the final preform structure and a layer of outer cladding material.

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: This invention provides an optical fiber wiring board having excellent optical property, high reliability and high mounting property. This invention relates to an optical fiber component for connection having a substrate on which a plurality of optical fibers being wired, wherein a foam polymer layer is provided on a surface of the substrate wiring the optical fibers, or both on a surface of the substrate wiring the optical fibers and on a surface opposite to the surface of the substrate wiring the optical fibers, or so that whole of substrate is covered. The optical fiber component of the present invention may be further provided with a protective layer and may be filled with a filler. This invention provides also a manufacturing method of the optical fiber component for connection.

Abstract: The present invention provides methods for manufacturing microstructured optical fibers having an arbitrary core size and shape. According to one embodiment of the invention, a method of fabricating a photonic band gap fiber includes the steps of forming an assembly of stacked elongate elements, the assembly including a first set of elongate elements, the first set of elongate elements defining and surrounding a core volume, and a second set of elongate elements surrounding the first set of elongate elements, wherein the core volume defined by the first set of elongate elements has a shape that is not essentially an integer multiple of the external shape of the elongate elements of the second set of elongate elements; including the assembly in a photonic band gap fiber preform; and drawing the photonic band gap fiber preform into the photonic band gap fiber.

Abstract: A microchannel plate (P) for receiving photoelectrons includes a plate-like substrate web (W) formed from a plurality of micro-tubules (10) of a single type of cladding glass (12) and defining a pair of opposite faces (14a and 14b). The substrate web (W) further includes a plurality of microchannel passages (16) extending between the opposite faces (14a and 14b) and having openings (18a and 18b, respectively) in both of the opposite faces (14a and 14b). The microchannel openings (18) have funnel-like entries or openings (20) formed in the substrate web (W) with at least one of the opposite faces (14).

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: The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

Abstract: The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

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: The present invention provides a method for drawing microstructured fibers. A preform having a first set of holes and a second set of holes is provided, and the first set of holes is coupled to a first pressure system, while the second set of holes remains substantially uncoupled to the first pressure system. The pressures of the sets of holes may be independently set or controlled to yield a desired hole geometry in the drawn microstructured optical fiber. The present invention also provides preforms suitable for use with the methods of the invention.

Abstract: A method of manufacturing a compact fiber coupler. On a semiconductor substrate, a V-groove with a radius curvature R is formed. Then, a glue is positioned at both sides of the V-groove, and the glue is absorbed from both sides of the V-groove by capillarity. A first optical fiber and a second optical fiber are respectively fixed in the V-groove so that the cladding of the first optical fiber and the second optical fiber can be polished to form a first side-polished region and a second side-polished region. Thus, the compact fiber coupler is accomplished by aligning and fusing the first side-polished region and the second side-polished region together, in which a coupling region is formed between the first side-polished region and the second side-polished region.

Abstract: A method of making a fiberoptic dental light probe having a bent distal end with a tapered tip. The method includes the step of heating just the mid-section of a vertically-disposed, solid, cylindrical fused fiberoptic rod and permitting the midsection to stretch and thin under its own weight by the force of gravity. Local heating of the mid-section is accomplished with a high-temperature small flame, such as the flame emitted by a gas-fired blow torch. The heat is removed when the rod stretches to a predetermined length, and then after the mid-section cools, the mid-section is cut to produce a pair of identical tapered tip probes. Thereafter, the distal ends of the probes can be bent to a desired angle and the ends of the probes can be cut to size, ground, and polished. A unique probe configuration is also provided.

Abstract: A microporous structure can be formed from ductile material such as glass into an axially extended outer wall surrounding a plurality of singular micro-passages surrounded by the outer wall to provide an open area that extends continuously over the length of the outer wall. The diameter of the micro-passages will usually not exceed 25 &mgr;m and are more in range of from 0.5 to 5 &mgr;m. The structure is particularly useful as frits for the containment of packing in capillaries for chromatograph applications and more generally as flow restrictors. Continuous open diameters of the micro-passages have a relatively straight flow path that reduces pressure drop relative to the random arrangement of other frits while still providing the desired containment.

Abstract: Disclosed is a method of making a photonic crystal preform which provides improved properties of the photonic band-gap crystal waveguide fiber drawn therefrom. The photonic crystal preform defect is formed using materials having a particular shape or composition so that the defect walls are preferentially etched away to provide a photonic band-gap crystal waveguide fiber having a smooth walled defect.

Abstract: The invention provides a production method for a PMF. Two or more bores at regular intervals are formed in a glass rod including a core and a clad so that the bores may be located on a concentric circle around a center axis of the glass rod. A stress applying member is inserted into the bore. The glass rod and the stress applying member may be heated before or after inserting. The glass rod with the stress applying is drawn without exposure to the atmosphere after heating in order to form an optical fiber.

Abstract: A method of producing an all glass, non-porous, multi-component photonic band-gap fiber is provided. The fiber is formed by creating a preform having a plurality of low refractive index glass rods and a plurality of high refractive index glass rods arranged in a pre-determined pattern between the low refractive index glass rods. The preform is heated and drawn to form the non-porous photonic band-gap fiber.

Abstract: A biosensor for direct analysis of nucleic acid hybridazation by use of an optical fiber functionalized with nucleic acid molecules and fluorescence transduction is disclosed. Nucleic acid probes are immobilized onto the surface of optical fibers and undergo hybridization with complementary nucleic acids introduced into the local environment of the sensor. Hybridization events are detected by the use of fluorescent compounds which bind into nucleic acid hybrids. The invention finds uses in detection and screening of genetic disorders, viruses, and pathogenic micoorganisms. Biotechnology applications include monitoring of gene cultures and gene expression and the effectiveness (e.g. dose-response) of gene therapy pharmaceuticals. The invention includes biosensor systems in which fluorescent molecules are connected to the immobilized nucleic acid molecules. The preferred method for immobilization of nucleic acids is by in situ solid phase nucleic acid synthesis.

Abstract: This invention provides an optical fiber wiring board having excellent optical property, high reliability and high mounting property. This invention relates to an optical fiber component for connection having a substrate on which a plurality of optical fibers being wired, wherein a foam polymer layer is provided on a surface of the substrate wiring the optical fibers, or both on a surface of the substrate wiring the optical fibers and on a surface opposite to the surface of the substrate wiring the optical fibers, or so that whole of substrate is covered. The optical fiber component of the present invention may be further provided with a protective layer and may be filled with a filler. This invention provides also a manufacturing method of the optical fiber component for connection.

Abstract: The present invention provides biosensors, apparatus and methods for selectively detecting at least one complementary oligonucleotide target specie in a fluid sample containing a mixture of different oligonucleotide fragments. One preferred embodiment of the biosensor is as a unitary fiber optic array having species of single stranded nucleic acid disposed as individual deposits in aligned organization upon multiple strand end faces at differing spatial positions on the distal array end surface.

Abstract: A method is provided for making a photonic band gap fiber including the steps of etching a preform and then drawing the preform into a photonic band gap fiber. Glass tubes are bundled and then formed into a photonic crystal perform having a number of passageways by reducing the cross-section of the bundle. One of the passageways is enlarged by flowing an etchant through it. After cleaning, the band gap fiber is made from the etched photonic preform, for example, by drawing.

Abstract: An optical fiber with a non-circular cross-section is realized by creating a void having the desired cross-section in a housing and filling the void with an optical material. This structure is then collapsed to solidify it and drawn to desired dimensions. The optical material may be rods, soot or ground material.

Abstract: The present invention provides biosensors, apparatus and methods for selectively detecting at least one complementary oligonucleotide target specie in a fluid sample containing a mixture of different oligonucleotide fragments. One preferred embodiment of the biosensor is as a unitary fiber optic array having an in-situ hybridization zone comprising not less than one specie of single stranded oligonucleotide disposed as individual deposits in aligned organization upon multiple strand end faces at differing spatial positions on the distal array end surface. In this manner, a collective of deployed, single specie, multiple fixed probes are presented for selective in-situ hybridization on-demand with at least one mobile complementary target specie ultimately bearing a joined identifying label. The biosensor provides for optical detection of in-situ hybridization on the distal end surface via the presence of the concomitantly disposed joined identifying label at the differing spatial positions.

Abstract: The method of making an optical fiber bundle (1) from individual optical fibers with good optical properties and a wider applicability includes temporarily mechanically holding individual optical fibers together and pushing them in a snug fit in a single metallic sleeve (3) made from a metallic material that has a sufficient high temperature strength at a forming temperature of the optical fiber glass; installing the optical fiber bundle (1) in a clamping device (4) in order to hold the optical fiber bundle fixed in an axial and radial direction; heating the end of the clamped optical fiber bundle (1) to the forming temperature, pressing the single metallic sleeve (3) on the optical fiber bundle and compressing the end of the optical fiber bundle in the single metallic sleeve with a forming tool (5) to shape or form the individual optical fibers in a hexagonal packing; cooling the shaped end of the optical fiber bundle (1) and removing the optical fiber bundle from the clamping device (4).

Abstract: A method of making an optical device comprises the steps of providing a body of vitreous material that is generally tubular along an axis. A portion of the body is molded with external mold structure for forming a bulbous region when the interior of the tube is pressurized. An axial portion is cut from the bulbous region to form a first coupling device with first and second axially oriented openings. This method can produce optical coupling devices with excellent optical quality in an economical manner.

Abstract: A method is disclosed for applying glue to a fiber optic coupler composed of a plurality of contiguously extending optical fibers, the fibers extending though the bore of a tube and through a longitudinally adjacent coupling region where the tube is collapsed around the fibers, the fibers being fused together in the coupling region, the diameters of the fibers in the coupling region being smaller than the diameters thereof in the bore. The method comprises: holding the coupler, and simultaneously injecting glue into both ends of the tube bore; wherein the coupler is oriented vertically, the glue being injected into the bore ends by positioning a hollow needle at each of the bore ends, the glue flowing through the needle in the bore at the top end of the tube at a rate greater than it flows through the needle in the bore at the bottom end of the tube.

Abstract: An optical fiber for transmitting radiation comprising two or more core regions, two or more core regions, each core region comprising a substantially transparent core material and having a core refractive index, a core length, and a core diameter, wherein said core regions are arranged within a cladding region, said cladding region comprising a length of first substantially transparent cladding material, having a first refractive index, wherein said first substantially transparent cladding material has an array of lengths of a second cladding material embedded along its length, wherein the second cladding material has a second refractive index which is less than said first refractive index, such that radiation input to said fiber propagates along at least one of said core regions. The cladding region and the core regions may be arranged such that radiation input to said optical fiber propagates along one or more said lengths of said core regions in a single mode of propagation.

Abstract: A method for threading a lead end of a fiber through the drawing apparatus of a fiber draw process. A prethread filament is fed through the apparatus of a draw process. One end of the prethread filament is then attached to the lead end of the fiber and used to pull the fiber through the apparatus of the draw process.

Abstract: A system for automated production of a fiber optic device includes a chamber regulating an environment and/or atmosphere within for the automated production of the fiber optic device. The system also includes a sealable input port, communicating with the chamber and substantially sealing the environment and the atmosphere of the chamber. The sealable input port receives an optical fiber for insertion therethrough into the chamber. A movable holding stage is included within the chamber, including at least one clamp to be secured to the optical fiber. An energy source is disposed within the chamber, and used to apply energy to the optical fiber. The system also includes a gripping device within the chamber. The gripping device includes a cavity adapted for receiving the optical fiber therethrough and for securing thereto.

Abstract: A method and apparatus are provided for removing protective coating material from a fiber optic cable including one or more optical fibers. A stream of hot inert gas is directed onto the cable to soften the protective coating material and blow it from the cable. The stream can be moved relative to the cable until the desired length of coating material has been removed.

Abstract: A method and apparatus are provided for removing protective coating material from a fiber optic cable including one or more optical fibers. A stream of hot inert gas is directed onto the cable to soften the protective coating material and blow it from the cable. The stream can be moved relative to the cable until the desired length of coating material has been removed.

Abstract: An automated method and apparatus for making optical fiber couplers is disclosed. The apparatus includes various processing stations under the control of a programmable controller. A fiber feeding system receives a set of optical fibers from a reel and guides them to the various processing stations. The fibers are guided into a fiber insertion fixture. The insertion fixture moves the fibers to the aperture of a glass capillary tube. The fibers are then stripped of a portion of their coating. The feeding system feeds the stripped fibers through the insertion fixture and into the glass tube. The fibers are severed and terminated. Subsequently, a burner heats the glass tube, causing it to collapse around the fibers to form a fiber coupler.

Abstract: The present invention relates to an apparatus and method of making a Dense Wavelength-Division Multiplexer (DWDM) using a Fused-Biconical Taper ("FBT") technique. The DWDM according to the present invention comprises a multiple of Multi-window Wavelength-Division Multiplexers ("MWDMs") which cascade together in several stages, each stage has several MWDMs having an identical window spacing. For a N-channel DWDM, there are 2.sup.m-1 MWDMs cascaded in m-th stage, and the window spacing of the m-th stage MWDMs is 2.sup.m-1 .DELTA..lambda., where m is from 1 to (logN/log2), for example, the first stage(m=1) having 1 MWDM and the window spacing is .DELTA..lambda., the second stage(m=2) having 2 MWDMs and the window spacing is 2.DELTA..lambda., the third stage(m=3) having 4 MWDMs and the window spacing is 4.DELTA..lambda., etc., and the (logN/log2)-th stage has (N/2) MWDMs with a window spacing (N/2).DELTA..lambda.. The number N could be 2, 4, 8, 16 or more.

Abstract: Fiber optic devices are manufactured in an automated environment using a combination of clamps to secure the optical fibers and movable gripping devices that transport the optical fiber during the fabrication process while maintaining control of the ends of the optical fibers. An optical fiber from a spool is removed by a despooling arm having a gripping device, and moveable grippers thread the optical fiber into a set of clamps and place the end of the optical fiber in a clamp designed to splice the fiber optic end to a lead of a testing device. The fiber optic device is formed by dynamically controlling the heating and pulling process based on detected coupling ratios, and hermetically sealed while secured within the clamps. The sealed fiber optic device is moved for testing or packaging using a transport arm having a series of clamps to maintain the position of the fiber optic device and the ends of the leads of the fiber optic device.

Abstract: A method and apparatus are provided for removing protective coating material from a fiber optic cable including one or more optical fibers. A stream of hot inert gas is directed onto the cable to soften the protective coating material and blow it from the cable. The stream can be moved relative to the cable until the desired length of coating material has been removed.

Abstract: The present invention provides a connecting member for facilitating connecting of optical fibers, and a connecting method in which the loss due to connecting is small. An optical fiber connecting member is composed of: a retaining portion having through-holes each of which has an inner diameter slightly larger than the outer diameter of optical fibers to be connected; and introduction portions which are integrally formed with and on the opposite end sides of the retaining portion and each of which has introduction grooves communicated with the through-holes to thereby make it easy to insert ends of the optical fibers into the through-holes. Further, the inner diameter of each of the through-holes is reduced by heating the connecting member to thereby make axis alignment of the optical fibers automatically to obtain connecting in which the connecting loss is reduced.

Abstract: The invention relates to the fabrication and use of biosensors comprising a plurality of optical fibers each fiber having attached to its "sensor end" biological "binding partners" (molecules that specifically bind other molecules to form a binding complex such as antibody-antigen, lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc.). The biosensor preferably bears two or more different species of biological binding partner. The sensor is fabricated by providing a plurality of groups of optical fibers. Each group is treated as a batch to attach a different species of biological binding partner to the sensor ends of the fibers comprising that bundle. Each fiber, or group of fibers within a bundle, may be uniquely identified so that the fibers, or group of fibers, when later combined in an array of different fibers, can be discretely addressed. Fibers or groups of fibers are then selected and discretely separated from different bundles.

Abstract: A method of making 1.times.2 or 2.times.2 overclad couplers, switches and the like such that the process is more reproducible and loss characteristics are improved. Such couplers are typically made by inserting the stripped portions of two active optical fibers into a tube, heating the tube midregion to collapse it onto the fibers and stretching the central portion of the collapsed midregion to achieve the desired coupling characteristics. The improvement involves the insertion of one or two spacer fibers into the tube bore along with the active fibers to take up empty space that had been present in tube bore and to prevent an active fiber from sagging and crossing over the other fiber when the tube is heated during the tube collapse step.

Abstract: The invention relates to the fabrication and use of biosensors comprising a plurality of optical fibers each fiber having attached to its "sensor end" biological "binding partners" (molecules that specifically bind other molecules to form a binding complex such as antibody-antigen, lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc.). The biosensor preferably bears two or more different species of biological binding partner. The sensor is fabricated by providing a plurality of groups of optical fibers. Each group is treated as a batch to attach a different species of biological binding partner to the sensor ends of the fibers comprising that bundle. Each fiber, or group of fibers within a bundle, may be uniquely identified so that the fibers, or group of fibers, when later combined in an array of different fibers, can be discretely addressed. Fibers or groups of fibers are then selected and discretely separated from different bundles.

Abstract: A method of bonding glass-based optical elements comprising the steps of positioning a first glass-based optical element relative to a second glass-based optical element, applying a glass-based bonding compound about the first and second optical elements, and applying sufficient localized heat to the glass-based bonding compound to cause the glass-based bonding compound to soften and fuse with the optical elements.

Abstract: Overclad fiber optic couplers are made by inserting the uncoated portions of a plurality of optical fibers into the bore of a glass tube, collapsing the tube midregion onto the fibers and stretching the central portion of the tube midregion. The present method utilizes a glass tube the bore of which includes a circular portion and a recess. A plurality of optical fibers are sequentially inserted into the tube by threading the coated end into the circular bore portion until the uncoated portion of fiber is centered in the tube. The uncoated portion of fiber is then transferred laterally into the bore recess. After all fibers have been threaded into the circular bore portion and transferred to the recess, a filler fiber is inserted into the circular bore portion. The resultant coupler exhibits low excess loss.

Abstract: The multi-fiber optical cross-coupler includes N peripheral fibers and a central fiber that are coupled together optically. The method of the invention for manufacturing such a cross-coupler consists in forming a multi-waveguide conductor by drawing a composite primary preform, the waveguides of the conductor being cylindrical elementary fibers embedded so that they are mutually parallel in mechanical and optical coupling cladding, said waveguides defining the fibers of the cross-coupler, and having opto-geometrical characteristics so that they are optically coupled over a defined length of said conductor, which length is cut off accordingly. Application to an optical coupler.

Abstract: The invention provides a process for fabricating a fiber optic microcable mposed of materials having properties which facilitate its manufacture. The microcable is comprised of an optical fiber core, a buffer surrounding the core, and a protective sheath surrounding the buffer consisting of an electromagnetic radiation cured resin impregnated with fibers suspended in the resin to enhance the resistance of the microcable to physical damage. The microcable is fabricated by soaking the fibers in an electromagnetic radiation curable resin, placing the wetted fibers around the core and buffer to form a matrix, and then irradiating the matrix with electromagnetic radiation to cure the resin.

Abstract: A varied ratio coupler, and a method of forming the same, constructed and arranged, in a unitary structure, to cause optical power in an input optical fiber to couple asymmetrically to at least two output optical fibers in a manner establishing different insertion losses between the input fiber and at least two output optical fibers. The coupler includes a central fiber surrounded by a close-packed ring of fibers. In certain preferred embodiments, the coupler has a bend that lies in a preselected plane and has a radius of curvature that is selected to provide the above difference in the insertion losses.

Abstract: Overclad fiber optic couplers typically include an elongated glass body having a solid midregion through which at least two glass optical fibers extend in optical signal coupling relationship. At each end of the midregion is an end region containing a bore from which optical fiber pigtails extend. In accordance with the invention, each end region includes a first projecting portion, one surface of which forms a ledge. That end of each bore opposite the midregion terminates at a recessed face that intersects the respective ledge. One end of at least the first fiber extends from the first bore. That portion of the first fiber outside the first bore has a coating that extends along the ledge, the coating terminating outside the first bore. A mass of glue extends between the ledge and the recessed face and encompasses the bare portion of the first fiber that extends along the first ledge and at least a portion of the first coating that extends along the first ledge.

Abstract: An optical fiber bundle for heat resistance and vacuum resistance which can be used even at a very high temperature or high vacuum is provided in economical manner. This is accomplished by a process for the production of an optical fiber bundle for heat resistance and vacuum resistance, which comprises making up optical fiber filaments each having a core part and a clad part into a bundle, closely fusion-bonding the end of the optical fiber bundle with a bonding glass and then subjecting the bonding glass to a crystallization treatment to increase the heat resistance.

Abstract: The method of manufacturing a multiferrule for optical fibers, the method consisting in fiber drawing a preform of silica that includes a plurality of mutually parallel channels, the method being characterized by the fact that said preform is made from a rod (1) of silica having a plurality of longitudinal grooves (3) uniformly distributed about an axis (2) and closed by at least one piece of silica (4) for defining said plurality of channels.

Abstract: A broadband optical fiber coupler comprising at least three continuous optical fibers fused at a region of coupling, at least one of the continuous optical fibers being dissimilar to others of the continuous optical fibers in the region of coupling, the region of coupling being of a length and the dissimilarity being of a degree to provide broadband response over a predetermined range of wavelengths. A related method for making a broadband optical fiber coupler is also disclosed.