Abstract: In the known method for producing an optical fiber, a coaxial arrangement comprising a core rod and an outer jacket tube is elongated, the coaxial arrangement being supplied in a vertical orientation to a heating zone and being softened therein zonewise, starting with the lower end thereof, and the optical fiber being withdraw downwards from the softened portion, whereby an annular gap existing between core rod and jacket tube is collapsed. Starting therefrom, in order to provided a method which makes it possible to produce optical fibers with a minimum curl and at low costs, the invention suggests that a quartz glass cylinder treated mechanically to its final dimension and having an outer diameter of at least 100 mm should be used as the jacket tube. An optical fiber obtained according to the method is characterized in that without the action of external forces it assumes a radius of curvature of at least 6 mm.

Abstract: A method is disclosed for the manufacture of optical fiber preforms using plasma enhanced chemical vapor deposition (PECVD). The invention consists of a cylindrical reactor in which material such as flourine-doped silica glass is deposited on a cylindrical silica rod. A furnace for regulating reactor temperature encases the reactor. A microwave generator coupled with a resonator and an H10 waveguide delivers microwave energy to the reactor, producing simultaneously symmetrical excitations in the E010 mode and a plasma surface wave in E01 mode located at the surface of the rod. A microwave plasma is scanned along the length of the rod through a slit in the reactor to deposit a homogeneous film of a desired thickness. The benefits of the present invention over the prior art include increased absorption of delivered power, and the ability to uniformly deposit films such as flourine-doped silica on rods with diameters of up to 30–35 mm and thus produce optical fiber preforms with diameters greater than 40 mm.

Abstract: The invention provides a low cost method of manufacturing high capacity preforms by chemical vapor deposition. More particularly, there is described a method of manufacturing an optical fiber preform, which method comprises the steps of providing a substrate tube of silica doped with sufficient chlorine to obtain an OH concentration of less than 100 ppb and doped with sufficient fluorine proportional to the chlorine doping to obtain a refractive index that is lower than that of a natural silica, depositing inner cladding and an optical core inside the substrate tube, collapsing the substrate tube to form a primary preform, and depositing outer cladding of said natural silica on the resulting primary preform. The invention is applicable to manufacturing optical fibers.

Abstract: A device and method is disclosed for manufacturing optical fiber preforms utilizing microwave plasma assisted chemical vapor deposition. Precursor gas is introduced to the face of a vertically mounted dielectric rod, and a plasma is struck by means of simultaneous excitation of an E01 type wave and an H type wave with rotating linear polarization. The silica rod is positioned so that its face is at the bottom of the tube. Precursor gas is delivered from a position below the face of the silica rod, and microwave energy, which travels through the rod to the rod face, is delivered from a source positioned above the rod. With this configuration, a uniformly dense plasma localized on the face of the rod can simultaneously deposit both a pure or doped core and a doped cladding. It is also useful for creating waveguides, preform cores for use as substrates in creating optical fiber preforms, capillaries and ceramic rods.

Abstract: A method of making an optical waveguide preform includes forming a preform including a first portion and a second radial portion, wherein the second portion includes a dopant, and wherein the first portion exhibits a density greater than the second portion. The method further includes stripping at least a portion of the dopant from the second portion. In a preferred embodiment, the stripped dopant has migrated in a previous processing step.

Abstract: A method for depositing one or more glass layers on the external surface of a rod-like glass preform. The method: i) places the preform in an enclosed space, ii) creates a sub-atmospheric pressure in the enclosed space, iii) supplies one or more reactive gases, which may or may not be doped, to the enclosed space, iv) generates a plasma zone in the enclosed space, and v) carries out a deposition reaction.

Abstract: Methods for modifying preform core ovality during and subsequent to the formation of an optical fiber preform. Prior to MCVD deposition on a starting tube, the outer diameter of the starting tube is altered by etching or a like process to modify its ovality. Additionally, after MCVD deposition forms the core rod, but prior to overcladding of the core rod, the code rod may be etched to change its ovality. Both methods may be used independently or in combination to modify the ovality and reduce PMD of optical fiber drawn from the core rod. An additional method includes etching the cladding material of a core rod having an oval or elliptical core such that the cladding material mirrors the shape of the oval core. During drawing, the perform created there from is placed under a surface tension, or pulled in a manner to generate a circular or near perfect circular optical fiber having desired ovality and low PMD.

Abstract: The present invention relates to a method of making a soot particle and apparatus for making such soot particle. Preferably the method of making the soot particle is substantially free of the step of combusting a fuel and substantially free of the step of forming a plasma. Preferably, the apparatus is devoid of a heating element associated with both combustion and formation of a plasma. A preferred technique for at least one heating step for forming the doped soot particle is induction heating.

Abstract: The present invention relates to a method of manufacturing an optical fibre by carrying out one or more a chemical vapour deposition reactions in a substrate tube, which method comprises the following steps:

Abstract: A method for manufacturing an optical device with a defined total device stress and a therefrom resulting defined birefringence and a therefrom resulting defined optical polarization dependence is disclosed. In a preferred embodiment, a lower cladding layer of an amorphous material with a first refractive index is provided and above that an upper cladding layer of an amorphous material with a second refractive index, which latter is manufactured from a material which is tunable in its stress. Between the lower and upper cladding layer an optical waveguide core is manufactured comprising an amorphous material having a third refractive index which is larger than the first and second refractive index. The optical waveguide core is thermally annealed, after which it has a defined waveguide core stress. The upper cladding layer is manufactured to have a cladding layer stress that together with the waveguide core stress results in the total device stress.

Abstract: The specification describes methods for the manufacture of very large optical fiber preforms wherein the core material is produced by MCVD. Previous limitations on preform size inherent in having the MCVD starting tube as part of the preform process are eliminated by removing the MCVD starting tube material from the collapsed MCVD rod by etching or mechanical grinding. Doped overcladding tubes are used to provide the outer segments of the refractive index profile thus making most effective use of the MCVD produced glass and allowing the production of significantly larger MCVD preforms than previously possible.

Abstract: A method of assembling two optical fiber tube preforms end-to-end without negatively impacting the local glass chemistry at the joint. The ends of two tubes to be joined together are reverse-tapered by a grinding such that the outside portion of the tube walls extend further outward than the inner portions of the tube walls. Two tubes having such ends are briefly heated and brought together, and the reverse taper minimizes the size of the cross-sectional area of the tube portions to be joined. A minimal amount of heat that does not significantly impact the glass chemistry at the joint is applied to the outside of the tubes to effect a tack weld that joins the tubes. Once the tack weld is in place, additional heat in combination with a vacuum force can be applied to the tubes, which completes the sealing of the weld.

Abstract: A method for manufacturing an optical device with a defined total device stress, birefringence and optical polarization dependence is disclosed. The method comprises first providing a tower cladding layer of an amorphous material with a first refractive index and then providing above the lower cladding layer an upper cladding layer of an amorphous material with a second refractive index. An optical waveguide core comprising an amorphous material having a third refractive index (larger than the first refractive index and the second refractive index) is provided between the lower and the upper cladding layers. The upper cladding layer is thermally annealed by keeping the upper cladding layer at a first temperature, then raising the temperature to a second temperature, maintaining the second temperature for an annealing time period, and lowering the temperature to a third temperature, after which the temperature is lowered to a fourth temperature.

Abstract: Embodiments of the present invention provide a highly uniform low cost production worthy solution for manufacturing low propagation loss optical waveguides on a substrate. In one embodiment, the present invention provides a method of forming a PSG optical waveguide on an undercladding layer of a substrate that includes forming at least one silicate glass optical core on said undercladding layer using a plasma enhanced chemical vapor deposition process including a silicon source gas, an oxygen source gas, and a phosphorus source gas, wherein the oxygen source gas and silicon source gas have a ratio of oxygen atoms to silicon atoms greater than 20:1.

Abstract: The present invention relates to a method for producing a preform, which is substantially free of OH impurities, for an optical fiber, wherein one or more quartz layers, which may or may not be doped, are deposited on the internal surface of a quartz glass support tube, in which method a furnace is moved axially with respect to the support tube, and after the quartz layers have been deposited the support tube is contracted into a bar-shaped preform while being heated, wherein the furnace comprises an electrical resistance furnace, in which furnace the support tube is rotated, with the space between the rotating support tube and the furnace being washed with an inert gas.

Abstract: A method of fabricating an optical fiber preform is disclosed which includes a step of outside deposition of silica possibly doped with at least one dopant by injecting at least one substance in the form of silica or a precursor of silica in the vicinity of a heating area created by a heating system during at least one pass of an injector system and the heating system along a longitudinal axis of the preform during which the relative positions of the injector and heating systems ore adjusted so that silica is deposited in the heated area regardless of the position of the heating system.

Abstract: A method for manufacturing a photomask material includes delivering a powder containing silicon dioxide into a plasma to produce silica particles and depositing the silica particles on a deposition surface to form glass.

Abstract: A method for performing high aspect ratio gap fill during planar lightwave circuit top clad deposition. A plurality of waveguide cores are formed on a substrate, the waveguide cores having a plurality of gaps there between. A cladding layer is formed over the waveguide cores and the substrate using a high-density plasma deposition process. The refractive index of the waveguide cores are controlled by using a dopant to be higher than the refractive of the cladding layer. An anneal process is performed on the cladding layer after the high-density plasma deposition process. The gaps between the waveguide cores can be smaller than 2 microns. The aspect ratio of the gaps between the waveguide cores can be greater than 3. The high-density plasma deposition process provides a very high purity USG (undoped silica glass) and BPSG (Boron Phosphorous silica glass) layers having a uniform refractive index.

Abstract: A device and method is disclosed for manufacturing optical fiber preforms utilizing microwave plasma assisted chemical vapor deposition. Precursor gas is introduced to the face of a vertically mounted dielectric rod, and a plasma is struck by means of simultaneous excitation of an E01 type wave and an H type wave with rotating linear polarization. The silica rod is positioned so that its face is at the bottom of the tube. Precursor gas is delivered from a position below the face of the silica rod, and microwave energy, which travels through the rod to the rod face, is delivered from a source positioned above the rod. With this configuration, a uniformly dense plasma localized on the face of the rod can simultaneously deposit both a pure or doped core and a doped cladding. It is also useful for creating waveguides, preform cores for use as substrates in creating optical fiber preforms, capillaries and ceramic rods.

Abstract: A method is disclosed for the manufacture of optical fiber preforms using plasma enhanced chemical vapor deposition (PECVD). The invention consists of a cylindrical reactor in which material such as flourine-doped silica glass is deposited on a cylindrical silica rod. A furnace for regulating reactor temperature encases the reactor. A microwave generator coupled with a resonator and an H10 waveguide delivers microwave energy to the reactor, producing simultaneously symmetrical excitations in the E010 mode and a plasma surface wave in E01 mode located at the surface of the rod. A microwave plasma is scanned along the length of the rod through a slit in the reactor to deposit a homogeneous film of a desired thickness. The benefits of the present invention over the prior art include increased absorption of delivered power, and the ability to uniformly deposit films such as flourine-doped silica on rods with diameters of up to 30-35 mm and thus produce optical fiber preforms with diameters greater than 40 mm.

Abstract: A method for making extreme ultraviolet lithography tool glass substrates includes generating a plasma, delivering reactants comprising a silica precursor and a titania precursor into the plasma to produce titania and silica particles, and depositing the titania and silica particles on a deposition surface to form a homogeneous titania-doped silica. The invention provides for homogeneous glass substrates that are free of striae variations and provides for beneficial extreme ultraviolet lithography reflective optics.

Abstract: The invention relates to the field of processes for manufacturing optical fiber preforms. This is a process for manufacturing optical fiber preforms that includes a step of drawing the preform with a draw ratio that remains constant for the same preform and may vary from one preform to another depending on their respective mean diameters so as to reduce the variation in mean diameter between preforms or else a process for manufacturing optical fiber preforms that includes a step of compressing the preform with a compression ratio that remains constant for the same preform and may vary from one preform to another depending on their respective mean diameter so as to reduce the variation in mean diameter between preforms.

Abstract: Disclosed is a substantially transparent glass-ceramic ceramic, and a method for making a glass-ceramic, exhibiting an aluminogallate spinel crystal phase and having a glass-ceramic composition that lies within the SiO2—Ga2O3—Al2O3—K2O—Na2O— system and particularly consisting essentially, in weight percent on an oxide basis, of 25-55% SiO2, 9-50% Ga2O3, 7-33% Al2O3, 0-20% K2O, 0-15% Na2O, 0-6 Li2O and 5-30% K2O+Na2O, the glass ceramic microstructure containing a crystal phase comprising at least 5%, by weight, of aluminogallate spinel crystals. Another aspect disclosed is optical element selected from the group consisting of an optical fiber, a gain or laser medium, and an amplifier component, a saturable absorber, with the element comprising a transparent glass-ceramic of the same composition and containing a crystallinity of at least about 5% by weight of aluminogallate spinel crystals.

Abstract: Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.

Abstract: A method of fabricating an optical fiber preform includes an operation of glazing the outside surface of the preform using inductive heating, of the plasma torch type, for localized heating of the preform. A flow of gas between the plasma and the preform in the area of the outside face of the preform on which the plasma impinges reduces the power of the plasma in this outside surface area.

Abstract: A method and apparatus for making optical fiber preforms using simultaneous plasma deposition on the inside and outside surface of a starting tube. A starting tubular member is rotated, CFOT chemicals are selectively injected into the plasma torch, and CFIT chemicals are selectively injected to flow through the hollow of the tube. The plasma torch is traversed along the tubular member to simultaneously deposit soot on the inside and outside surface. The soot on one or both surfaces may be consolidated into a silica layer as it is deposited. The plasma torch is traversed again to deposit additional soot, and/or consolidate previously deposited soot, on one or both surfaces. The process is repeated until a predetermined amount of silica is formed on the tubular member. The tubular member is then collapsed. Optionally, additional plasma deposition is performed during or after the collapsing.

Abstract: Glass is produced by depositing presintering composition on a preform set into move in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of the presintering composition while optionally a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas.

Abstract: The invention relates to the field of PCVD methods of making an optical fiber and apparatuses for use in PCVD methods. The disclosed methods and apparatuses improve the PCVD process by enhancing the efficiency of the deposition process. The use of the disclosed methods and apparatuses, individually or in combination thereof, will result in at least reducing the time necessary to deposit a predetermined amount of glass on a substrate.

Abstract: A method and apparatus for making optical fiber preforms using modified chemical vapor deposition (MCVD) A starting tubular member is installed on a chemical vapor deposition apparatus and, using MCVD, a predetermined amount of selectively doped silica is deposited and consolidated on the inner surface to form an intermediate uncollapsed preform tube. At least a portion of the intermediate uncollapsed preform tube is removed from the chemical vapor deposition apparatus, installed in a collapsing apparatus and collapsed. The collapsing uses an oxy-hydrogen burner or a plasma torch. Optionally, additional deposition is performed during the collapsing operation. A stretching may be performed concurrent with the collapsing.

Abstract: Embodiments of the present invention provide a highly uniform low cost production worthy solution for manufacturing low propagation loss optical waveguides on a substrate. The method comprises depositing an optical core using a high-density plasma deposition process. The method is particularly advantageous in forming high contrast refractive index optical cores, such as SiOxNy, with drastically reduced propagation loss. In one embodiment the high-density plasma deposition process is an HDP-CVD process. In another embodiment the high-density plasma deposition process is an HDP-ECR process. In one embodiment, a method of forming an optical waveguide comprises forming at least one optical core on an undercladding layer of a substrate using a high-density plasma deposition process.

Abstract: A method for manufacturing optical fiber preform and fiber. According to the method, a core cane segment is formed with a refractive index delta preferably between 0.2% and 3% that is most preferably formed by an OVD method. A sleeve is formed including at least one down-doped moat preferably having a refractive index delta between −0.1% and −1.2% and at least one up-doped ring preferably having a refractive index delta between 0.1% and 1.2%. The sleeve is formed by introducing glass precursor and dopant compounds into a cavity of a preferably silica glass tube (e.g., one of an MCVD and PCVD method). The core cane segment is inserted into the sleeve and the sleeve is collapsed onto the core cane segment to form a core-sleeve assembly. The core-sleeve assembly is again drawn into a cane and additional cladding is preferably formed thereon. Optical fiber may be drawn from the preform in a conventional draw apparatus.

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 method of manufacturing a glass article, such as an optical fiber. The method comprises the steps of providing a glass tube with an annular passage, forming a preform from the glass tube while maintaining the annular passage, and drawing the preform into the glass article such that the annular passage closes during drawing. The preform is formed by the steps of providing glass on an inner surface of the glass tube while maintaining the annular passage and providing glass on an outer surface of the glass tube. The preform has a predetermined value &agr; that is an inner diameter of the preform after providing glass on the inner surface divided by an outer diameter of the glass tube. The preform has a predetermined value &bgr; that is the inner diameter of the preform after providing glass on the inner surface divided by the outer diameter of the preform.

Abstract: The invention provides a method of passivating an optical fiber or preform by reducing a hydrogen content in the fiber or preform using a deuterium ion plasma passivation process or a high temperature deuterium gas passivation of preforms for exchanging at least a portion of the hydrogen contained within the optical fiber or preform with deuterium. The deuterium plasma is generated from a deuterium gas. To further reduce the passivation, the optical fiber or preform are heated in the deuterium plasma. If desired, the deuterium plasma is applied to an inner wall of a preform tube before collapsing the preform tube into a preform rod.

Abstract: A silica-based core rod is traversed by a heat source along its longitudinal axis, to provide heated, softened regions. During the traverse, compressive or tensile movements are provided along the rod's longitudinal axis, these movements inducing, respectively, increases or decreases in the core diameter at the softened regions. By providing selective core diameter increases and/or decreases across the entire length of the core rod, a desired core diameter profile is attained. It is possible to attain a substantially uniform core diameter, or a varying core diameter profile that provides particular properties, such as systematically varying dispersion. In addition, due to the ability to increase core diameter and core rod diameter in a controlled manner, it is possible to make larger core rods, and in turn larger fiber preforms, than presently possible.

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: 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 of making an optical waveguide preform includes forming a preform including a first portion and a second radial portion, wherein the second portion includes a dopant, and wherein the first portion exhibits a density greater than the second portion. The method further includes stripping at least a portion of the dopant from the second portion. In a preferred embodiment, the stripped dopant has migrated in a previous processing step.

Abstract: A method for manufacturing a photomask material includes delivering a powder containing silicon dioxide into a plasma to produce silica particles and depositing the silica particles on a deposition surface to form glass.

Abstract: Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.

Abstract: A method for manufacturing optical fiber preform and fiber. According to the method, a core cane segment is formed with a refractive index delta preferably between 0.2% and 3% that is most preferably formed by an OVD method. A sleeve is formed including at least one down-doped moat preferably having a refractive index delta between −0.1% and −1.2% and at least one up-doped ring preferably having a refractive index delta between 0.1% and 1.2%. The sleeve is formed by introducing glass precursor and dopant compounds into a cavity of a preferably silica glass tube (e.g., one of an MCVD and PCVD method). The core cane segment is inserted into the sleeve and the sleeve is collapsed onto the core cane segment to form a core-sleeve assembly. The core-sleeve assembly is again drawn into a cane and additional cladding is preferably formed thereon. Optical fiber may be drawn from the preform in a conventional draw apparatus.

Abstract: A plurality of glass deposition targets are rotated simultaneously and a first plasma torch, having a coil diameter larger than the sum of the target diameters, deposits glass simultaneously on the plurality. After the diameter of the targets reaches a threshold a second plasma torch is used. The diameter of the second plasma torch can provide for simultaneous deposition. In a further embodiment, after the target diameter reaches a second threshold a third plasma torch is used. In a further embodiment the spacing between the axes of rotation of the targets is widened as the target diameter increases. In a still further embodiment a single plasma torch includes movable concentric tubes within its coil to selectively operate as any of a plurality of different diameter plasma torches.

Abstract: Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.

Abstract: A method for making silica includes delivering a silica precursor comprising a pseudohalogen to a conversion site and passing the silica precursor through a flame to produce silica soot.

Abstract: The method includes axially modulating at least one plasma build-up pass in order to improve the opto-geometrical properties of the preform. The modulation preferably takes place during the final passes of plasma build-up and takes place by modulating the build-up grain flow rate. The diameter of the preform is evaluated (6), and a build-up control device (8) regulates grain flow rate (11, 5) in application of the above method.

Abstract: The invention provides a low cost method of manufacturing high capacity preforms by chemical vapor deposition. More particularly, there is described a method of manufacturing an optical fiber preform, which method comprises the steps of providing a substrate tube of silica doped with sufficient chlorine to obtain an OH concentration of less than 100 ppb and doped with sufficient fluorine proportional to the chlorine doping to obtain a refractive index that is lower than that of a natural silica, depositing inner cladding and an optical core inside the substrate tube, collapsing the substrate tube to form a primary preform, and depositing outer cladding of said natural silica on the resulting primary preform. The invention is applicable to manufacturing optical fibers.

Abstract: Fused silica created by pyrolysis of SiCl4 are introduced in a powder state into a vacuum chamber. Pluralities of jet streams of fused silica are directed towards a plurality of heated substrates. The particles attach on the substrates and form shaped bodies of fused silica called preforms. For uniformity the substrates are rotated. Dopant is be added in order to alter the index of refraction of the fused silica. Prepared soot preforms are vitrified in situ. The material is processed into quartz tubes for fiber optics and other applications, quartz rods for fused silica wafers for semiconductors and various optical applications and quartz plates for wafer processing and optical windows.

Abstract: Silica grain of desired properties and size is created in a vacuum chamber. Fine silica powder is injected in the chamber or silica powder is formed in situ by combusting precursors. A plasma is formed centrally in the chamber to soften the silica powders so that they stick together and form larger grains of desired size. The grains are collected, doped, fused and flowed into tubes or rods. A puller pulls the tube or rod through a chamber seal into a lower connected vacuum chamber. The tube or rod is converted to rods and fibers or plates and bars in the connected chamber. Fused silica in a crucible tray is subjected to ultrasound or other oscillations for outgassing. Gases are removed by closely positioned vacuum ports.

Abstract: The invention relates to manufacturing glass fiber preforms. It relates to a method comprising rotating preform about its own axis, and displacing a plasma torch in translation relative to the preform in a direction parallel to the axis of the preform, the axes of the flame and of the preform and being offset by a certain distance, and then inserting glass powder into the plasma flame under gravity. According to the invention, the glass powder is accelerated before penetrating into the plasma flame by means of an accelerator gas, and the offset distance between the axes is reduced with increasing acceleration of the powder. The invention is applicable to manufacturing glass fibers, and in particular optical fibers.

Abstract: A waveguide having an angled surface is created by depositing an optical core material onto a substrate having two levels. In one embodiment, a high density plasma deposition may be used to deposit the optical core material.