Abstract: Provided is a method of manufacturing an optical fiber base material having at least four layer including a core, a first cladding, a second cladding containing fluorine, and a third cladding. The manufacturing method comprises preparing a starting base material that includes the core and the first cladding; forming a porous intermediate glass base material by supplying glass raw material and oxygen to a high-frequency induction thermal plasma torch to synthesize glass fine particles that are then deposited on a surface of the starting base material; forming an intermediate glass base material that includes the core, the first cladding, and the second cladding containing fluorine, by heating and vitrifying the porous intermediate glass base material in an atmosphere containing fluorine; and providing the third cladding on the outer surface of the intermediate glass base material.

Abstract: A method for the production of a macroporous ceramic foam, wherein: (a) forming a ceramic slip comprising a substantially homogeneous mixture of a ceramic particulate, an organic binder in a liquid carrier, and optionally one or more surfactants, wherein at least one surfactant is present if the organic binder does not function as a surfactant, and wherein the ceramic slip preferably has a viscosity in the range of from 15 to 200 mPas?1; (b) foaming the ceramic slip; and (c) heating the foamed ceramic slip at a temperature sufficient to substantially burn out the organic binder. The macroporous ceramic foam is suitable for use in biomedical applications such as synthetic bones, tissue engineering scaffolds or drug delivery devices.

Abstract: Disclosed is a method of fabricating an optical fiber or an optical device doped with reduced metal ion and/or rare earth ion, comprising steps of: forming a partially-sintered fine structure in a base material for fabricating the optical fiber or the optical device; soaking the fine structure into a doping solution containing a reducing agent together with metal ion and rare earth ion during a selected time; drying the fine structure in which the metal ion and/or rare ion are/is soaked; and heating the fine structure such that the fine structure is sintered.

Abstract: The present invention relates to a method for manufacturing a preform for optical fibers via a vapor deposition process in which the position of the reversal point near the substrate tube's supply side shifts along the longitudinal axis of the substrate tube during at least part of the deposition process.

Abstract: A method for manufacturing a glass rod (106), which is a parent material of an optical fiber (350), comprising: adjusting a vertical inclination of a standard rod (138) having a predetermined straightness; and heating and elongating a base material (102), which is a parent material of the glass rod (106), along an axis of the standard rod (138), the vertical inclination of which is adjusted, to generate the glass rod (106).

Abstract: The specification describes ceram-glass compositions useful for electro-optic devices. The compositions have active ferroelectric ingredients in a tellurium oxide host. Proper processing of the ceram-glass produces highly transparent material with desirable ferroelectric properties. The ceram-glass materials can be used for electro-optic devices in both bulk and thin film applications.

Abstract: A fiber (106) having low polarization mode dispersion is made by heating the end of a preform (100) with a furnace (101). The fiber is drawn from the heated end. The fiber passes between two rollers (102, 104). As the fiber passes therebetween, the angular tilt of each of the rollers is changed so that a spin is imparted to the fiber.

Abstract: There is provided an optical fiber drawing furnace capable of drawing an optical fiber having small non circularity, which drawing furnace includes a muffle tube, in which an optical fiber preform is supplied, a heater surrounding the muffle tube, a plurality of electrode connecting portion extending from the heater, a plurality of electrodes connected to electrode connecting portions, and in conjunction therewith to an electric power source, and unifying means for unifying the temperature distribution along the circumferential direction.

Abstract: Disclosed is a method of protecting glass optical fiber preforms and glass precursor elements for making optical fiber preforms, wherein the preform or glass precursor element is stored within a protective bag. The protective bag preferably has anti-static agents incorporated therein. The protective bags can be employed to protect any glass precursor element used in making optical fiber preforms, for example, glass core canes, glass tubes, or the optical fiber preforms themselves.

Abstract: In an optical fiber coupler making apparatus which makes an optical fiber coupler by thermally fusing a plurality of optical fibers together by use of a heater and then elongating thus thermally fused part, the heater comprises a heating element which is made of zirconia and which has a slit for containing the optical fibers. The inner face of the heating element is preferentially heated due to a characteristic of its material. Consequently, if optical fibers are contained in the fiber receiving slit, then they can be thermally fused at a sufficiently high temperature in a short period of time, whereby reducing mingling of impurities into the optical fiber coupler. Therefore, the heating element made of zirconia is effective as means for preventing impurities from mingling from the outside thereof. Also, performances of the heating element can be maintained over a long period of time even if the optical fibers are thermally fused at a high temperature.

Abstract: A porous optical fiber preform dehydration and sintering apparatus capable of improving the sealing performance between an upper lid and an elevating shaft and between the upper lid and a furnace tube or a furnace body, wherein an upper opening of a furnace tube for accommodating a porous optical fiber preform is shut by the upper lid, a preform holder is provided at the bottom end of an elevating shaft passing through the upper lid to be freely elevated therethrough, the porous optical fiber preform in the furnace tube is heated by a heater provided around the outer circumference of the furnace tube, the upper lid is formed by a metal, the preform holder is formed by a quartz glass or a ceramic, a corrosion-resistant layer is provided on an inner surface of the upper lid, a seal member made of rubber or resin is provided in an elevating shaft passage of the upper lid.

Abstract: A method for producing an optical fiber preform starting with a first-generation target typically comprising pure silica. A plasma torch deposits an annular region of doped silica to form an intermediate structure. The intermediate structure is drawn down to a second-generation target and another annular region of doped silica is deposited. The process is repeated a plurality of times until an Nth generation target is formed. The deposition optionally employs repeated cycles of depositing a plurality of layers of silica at a high traversal rate without sintering, followed by periodic sintering. In a further embodiment, stabilizer bars extending out from the plasma coils improve distribution of the deposition material. Another embodiment injects the source gas into a particular region of the plasma for control of soot deposition.

Abstract: The refractive index profile of a multimode optical preform, fabricated by MCVD for example, is modified in the longitudinal direction by removing selected amounts of core material from the wall of a central hole through the preform prior to collapse. The amount of core material to be removed is determined by measuring the refractive index profiles of optical fibers drawn from a number of precursor preforms at various locations along the length of the drawn fibers, averaging their profiles, and then comparing those averages with a desired profile. The refractive index profile is indirectly measured by bandwidth measurements, which are related to the alpha value a selected parameter (e.g., bandwidth) at various locations along the length of a fiber drawn from a previously fabricated preform. This parameter is then compared with desired values of that parameter at the various locations, and the differences are used to calculate the amount of core material that needs to be removed.

Abstract: A method for fusing an optical fiber preform comprises fusing the preform while blowing an oxidative gas against the preform to be fused from upper and lower directions of a fusing burner unit. An apparatus for carrying out the method includes a plurality of nozzles for preventing deposition of silica cloud, which are each set at an angle, &thgr;, of blowing the oxidative gas relative to the preform being drawn such 20°≦&thgr;≦60°.

Abstract: A method of manufacturing an optical fiber preform (3) comprising: forming at least one silica-based outer deposition layer (23) by depositing silica on a primary preform (24) constituted by a bar mainly comprising silica and including a silica-based outer peripheral portion (22), the method being characterized in that the viscosity of the outer deposition layer (23) is adjusted to be substantially identical to the viscosity of the outer peripheral portion (22) of the primary preform (24) by adding to the silica, over a substantial portion of the outer deposition layer (23), at least one compound selected from the group formed by the following compounds: CaF2, MgF2, AlF3, B2O3, and Al2O3.

Abstract: A method and device for providing an optical fiber secondary preform by collapsing an over-cladding tube on an optical fiber primary preform is disclosed in the present invention. The device for over cladding the optical fiber primary preform includes a hand bar as a first supporter for supporting the optical fiber primary preform, which hand bar has a sealing-up part of the over-cladding tube on an outer diameter part thereof and also includes a supporting handle tube as a second supporter for supporting the over-cladding tube, which the purity of the supporting handle tube is different from that of the over-cladding tube. Also the supporting handle tube includes a ring to make it equal two centers of the optical fiber primary preform and the over-cladding tube.

Abstract: The present invention relates to a novel process for the production of sequences of interference layers composed of layers i of prescribed thicknesses d(i) and refractive indices n(i). In this process a stack of at least two layers i of glasses having refractive indices n(i) and thicknesses d0(i), which are each larger than the predetermined thicknesses d(i) by the same multiplying factor, is provided. The stack is heated to a temperature above the transformation temperature of the glasses and during or after heating, the stack is drawn in such a manner that the individual layers obtain the prescribed thicknesses d(i). After this the drawn stack is cooled.

Abstract: An apparatus and method for sealing the top of an optical waveguide draw furnace is disclosed. The apparatus includes an assembly constructed and arranged to removably cover the top of the draw furnace while mating with the downfeed handle. The apparatus includes an elongated sleeve having a base and a sealing mechanism positioned on the sleeve at a location remote from the base. The sleeve defines a chamber for receiving the downfeed handle, and the sealing mechanism is arranged with respect to the sleeve to mate with the downfeed handle received in the chamber. In one aspect of the invention, the apparatus further includes an inert gas purge for providing an inert atmosphere within the chamber. A method of sealing the top of an optical waveguide draw furnace is also disclosed.

Abstract: A method and apparatus for producing a glass base material for an optical fiber. A material for an optical fiber and a reaction gas are jetted from a burner connected to a material line and a gas line toward a surface of a quartz substrate, in order to deposit a soot-like reaction product on the substrate at a predetermined position to thereby produce a glass base material for an optical fiber. Dry air is introduced into a reaction container in an amount of 4 to 8 times the amount of water vapor that is generated due to flame hydrolysis during the reaction.

Abstract: An optical fiber is rolled by a swing motion of a swing guide roller in order to impart a predetermined twist to it effectively, and its polarization dispersion is suppressed equivalently as in a perfectly circular concentric optical fiber. A method of manufacturing such an optical fiber is also provided. As a swing guide roller swings, the optical fiber is rolled on its roller surface, so that a clockwise twist and a counterclockwise twist are imparted to the optical fiber alternately. At this time, the optical fiber is fitted in a V-shaped narrow groove formed at the central portion of the roller surface of a next-stage first stationary guide roller provided just beside the swing guide roller. Rolling of the optical fiber on the roller surface of the first stationary guide roller is suppressed, thereby helping smooth rolling of the optical fiber on the roller surface of the swing guide roller.