Abstract: A method for manufacturing an optical fiber having uniform refractive index profile, and substantially reduced macrobending loss and attenuation loss is provided comprising controlling one or more of parameters including concentration of dopant in outer region and inner region of the core region with respect to middle region of the core region of the optical fiber preform, duration of dehydration process step, concentration of chlorine gas to control refractive index of outer region and inner region of the core region for achieving a fiber having substantially uniform refractive index profile, and substantially reduced macrobending loss and attenuation loss.

Abstract: Multi-flame burner wherein each flame is separated with respect to the neighboring flame by at least one separating tube made of a heat resistant material, for example, quartz glass or ceramic material. The burner also has a plurality of co-axial pipes, preferably made of a metallic material. The cross section of the upper end of the separating tube can be modified in order to increase the deposition rate of the burner. Methods for manufacturing optical fibre preforms by vapour deposition using the multi-flame deposition burners.

Abstract: Described herein is a method for making a depressed index cladding for the inner cladding of an optical fiber. The method involves making the depressed index cladding in two steps. The innermost portion of the inner cladding is produced using a soot method, thereby deriving the advantages of the soot method for the region of the cladding that carries the most optical power, then forming the remaining portion of the inner cladding layer using a rod-in-tube step. This method effectively marries the advantages and disadvantages of both methods.

Abstract: Disclosed are a method for fabricating an optical fiber preform and a method for fabricating an optical fiber using the optical fiber preform. The method for fabricating the optical fiber preform including the steps of: (a) growing a first soot preform on a starting member by a soot deposition; (b) dehydrating the first soot preform; (c) sintering the first dehydrated soot preform to obtain a first glassed optical fiber perform; (e) growing an over-clad soot layer on the first optical fiber preform by soot deposition to obtain a second soot preform; and (f) sintering the second soot preform so as to obtain a second optical fiber preform which is glassed, wherein an average density of the first soot preform is substantially within a range of 0.19˜0.30 g/cc, and the average density of the over-clad soot layer is substantially within a range of 0.5˜0.75 g/cc.

Abstract: Disclosed is a method for fabricating an optical fiber preform. The method includes: (a) growing a first soot preform on a starting member along a lengthwise direction of the starting member by a soot deposition; (b) dehydrating the first soot preform; (c) sintering the dehydrated first soot preform, to obtain a first glassed optical preform; and (d) elongating the first optical fiber preform by heating the first optical fiber with a heat source that excludes hydrogen, wherein the first glassed optical fiber is elongated by means of only a heat source that excludes the use of hydrogen.

Abstract: Vapor Axial Deposition (VAD) apparatus and method is provided. The VAD apparatus includes a first torch, a second torch, a thermometer, a controller, and a moving device. The first torch grows a core by depositing a soot at an end of a soot preform arranged on an axis. The second torch grows a clad by depositing a soot on the face of the core. The thermometer detects the temperature of the end of the soot preform along the axis and the temperature of an other/lower portion of the core. The controller calculates a difference between a temperature (T1) of the end of the soot preform and a temperature (T4) of a lower portion of the core and controls the movement of the soot preform according to the difference. The moving device moves the soot preform along the axis according to the instruction of the controller.

Abstract: A multi-tube burner is provided which includes a cylindrical outermost nozzle and at least one cylindrical inner nozzle provided coaxially with the outermost nozzle to form annular jet openings for gases used to manufacture a glass preform. The angle between a center axis of an outer circumference of the outermost nozzle and a distal end portion of each of the inner nozzles is 90°± not more than 3°. Furthermore, the distance between the center axis of the outer circumference of the outermost nozzle and each of center axes of inner circumferences and outer circumferences of the inner nozzles is not more than 0.20 mm.

Abstract: A concentric multi-tubular burner for synthesizing glass particles having a center port group constituted by a combination of jet ports of raw material gas, combustible gas and oxygen gas, wherein an outer wall of the oxygen gas jet port in the center port group protrudes more toward a burner head than an inner wall of the oxygen gas jet port. The flow rate of oxygen gas jetted from the oxygen gas jet port of the center port group is controlled to be in a proper range.

Abstract: Methods, apparatus and precursors for producing substantially water-free silica soot, preforms and glass. The methods and apparatus make substantially water-free fused silica preforms or glass by removing water as a reaction product, removing water from the atmosphere, removing water from the transport process, or combinations thereof. In a first embodiment, substantially water-free soot, preforms or glass are achieved by using a hydrogen-free fuel, such as carbon monoxide, in the deposition process. In another embodiment, a soot producing burner has parameters that enable operation on a substantially hydrogen-free fuel. End burners, which minimize water production, are also described. Such water-free methods are useful in depositing fluorine-doped soot because of the low water present and the efficiency in which fluorine is incorporated. In another embodiment, glassy barrier layer methods and apparatus are described for minimizing dopant migration, especially fluorine.

Abstract: An apparatus for fabricating a soot preform for an optical fiber. The soot preform is fabricated by depositing glass particles on a starting rod capable of being rotated and pulled up. The apparatus comprises elements as follows. A reaction chamber is used for depositing the glass particles on the starting rod. An upper room is located above the reaction chamber for receiving the soot preform formed in the upper portion of the reaction chamber. At least one core burner is installed in the reaction chamber. A gas-supplying inlet is located in the top part of the sidewall of the reaction chamber closest to burner(s), and a gas-exhausting outlet is located in the top part of another sidewall opposite to the gas-supplying inlet. In addition, at least one cladding burner is installed in the reaction chamber.

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 glass tube for use in an optical fiber preform is produced by applying a first soot on an end face of a starting member to form an elongated, porous cylindrical soot core having a first density, and applying a second soot including SiO2 on the periphery of the soot core to form a porous soot cladding having a second density greater than that of the soot core at the periphery of the core. The core and the cladding are later heated together at a temperature sufficient for sintering to form a core glass and a cladding glass. Because the soot core collapses at a greater rate than the soot cladding during sintering, the core glass separates or delaminates radially from the cladding glass. The core glass is then removed from the surrounding cladding glass, and the latter is treated to provide a high purity glass tube suitable for use as part of an optical fiber preform.

Abstract: A synthetic quartz glass for optical use, to be used by irradiation with light within a range of from the ultraviolet region to the vacuum ultraviolet region, which contains fluorine, which has a ratio of the scattering peak intensity of 2250 cm?1 (I2250) to the scattering peak intensity of 800 cm?1 (I800), i.e. I2250/I800, of at most 1×10?4 in the laser Raman spectrum, and which has an absorption coefficient of light of 245 nm of at most 2×10?3 cm?1.

Abstract: These glass bodies are light weight porous structures such as a boules of high purity fused silica (HPFS). More specifically, the porous structures are supports for HPFS mirror blanks. Porous glass is made utilizing flame deposition of pure silica or doped silica in a manner similar to the production of high purity fused silica. Bubbles or seeds are formed in the glass during laydown. Finely divided silicon carbide (SiC) particles are used to form the bubbles. At least one layer of porous glass is formed in the boule.

Abstract: An apparatus for manufacturing an optical fiber soot, which comprises a core partition having an opening portion at core burner side provided on a periphery of a core burner, in a reactor of the apparatus to be used in a conventional VAD method.

Abstract: The specification describes a VAD method for dynamically controlling the growth rate of both the core soot and the cladding soot in response to separate growth monitors.

Abstract: A method for producing an optical fiber preform is provided in which the variation of the outer diameter in the longitudinal direction is minimized and a target quantity of glass is accumulated as a whole. Based on a predetermined relationship between three variables: the outer diameter of a starting rod being a first variable, the outer diameter of an optical fiber preform a second variable, and the timing for ending the glass particles depositing process a third variable, the starting rod and burners are subjected to relative reciprocating movement so as to deposit glass particles on the starting rod until the timing for ending the depositing process, and then the resulting deposit body is vitrified. The third variable may be the traverse velocity, the glass particles deposition time, or the weight of a soot glass deposit body.

Abstract: An isotopically-altered, silica based optical fiber is provided having lower losses, broader bandwidth, and broader Raman gain spectrum characteristics than conventional silica-based fiber. A heavier, less naturally abundant isotope of silicon or oxygen is substituted for a lighter, more naturally abundant isotope to shift the infrared absorption to a slightly longer wavelength. In one embodiment, oxygen-18 is substituted for the much more naturally abundant oxygen-16 at least in the core region of the fiber. The resulting isotopically-altered fiber has a minimum loss of 0.044 dB/km less than conventional fiber, and a bandwidth that is 17 percent broader for a loss range between 0.044-0.034 dB/km. The fiber may be easily manufactured with conventional fiber manufacturing equipment by way of a plasma chemical vapor deposition technique. When a 50 percent substitution of oxygen -18 for oxygen-16 is made in the core region of the fiber, the Raman gain spectrum is substantially broadened.

Abstract: Methods of fabricating an optical fiber preform and a method of fabricating an optical fiber of the invention realize the fabrication of an optical fiber having desirable transmission characteristics in the entire wavelength rage of about 1.3 to 1.6 &mgr;m. The fabrication method comprises a porous core rod producing step of depositing a first cladding (3) having an outer diameter D so as to surround a core (2) having an outer diameter d to produce a porous core rod (1) of D/d≧4.0 by VAD. Then, the porous core rod (1) is dehydrated to reduce the OH group concentration to 0.8 ppb or less by weight ratio. The porous core rod (1) is formed to be transparent for a vitrified core rod (4) and is heated and stretched. Thereafter, a second cladding is obtained by depositing a second porous cladding (5) around the vitrified core rod (4) by VAD to be dehydrated, transparent and vitrified.

Abstract: A method for manufacturing a glass base material for an optical fiber by forming a core rod having a core section and a portion of a clad, forming an additional clad by depositing glass particles on circumference of the core rod, and performing a sintering and vitrifying process on an obtained porous base material, includes the step of forming the core rod in order that the relation 3.75≦a/m≦6 is satisfied, where ‘a’ denotes an outer diameter of a section corresponding to the core rod, and ‘m’ denotes a mode field diameter at 1385 nm in wavelength with regard to the optical fiber obtained by drawing the glass base material.

Abstract: The doped silica core region of a core rod for an optical fiber preform is protected against unwanted fluorine doping during fluorine doping of the outer silica layer by selectively consolidating the core region prior to fluorine doping. Due to dopants in the core region, the soot in the core region consolidates before the soot in the outer undoped region. This inherent property allows the entire core rod to be heated prior to fluorine doping resulting in selective partial consolidation and preventing fluorine doping of the doped center core region. The process time required may be reduced by using incremental fluorine doping. In the incremental doping process the doping step is separated into a deposit step, where “excess” fluorine is deposited on the silica particles, and a drive-in step where atomic fluorine is distributed into the silica particles. The drive-in step is conveniently combined with the sintering or consolidation step to further enhance the efficiency of the doping process.

Abstract: A deposition system for depositing a chemical vapor onto a workpiece, including a deposition chamber having a plurality of components for performing chemical vapor deposition on the workpiece. The deposition chamber includes an inner skin made of Hasteloy for sealing the plurality of components and the workpiece from the air surrounding the deposition system, and an outer skin that encloses the inner skin and is separated from the inner skin by an air gap. The outer skin includes vents that create a convection current in the air gap between the inner skin and outer skin of the deposition chamber. The deposition system also has a gas panel for regulating the flow of gases and vapors into the deposition chamber, and a computer for controlling operation of the gas panel and the components in the deposition chamber.

Abstract: The doped silica core region of a core rod for an optical fiber preform is protected against unwanted fluorine doping during fluorine doping of the outer silica layer by selectively consolidating the core region prior to fluorine doping. Due to dopants in the core region, the soot in the core region consolidates before the soot in the outer undoped region. This inherent property allows the entire core rod to be heated prior to fluorine doping resulting in selective partial consolidation and preventing fluorine doping of the doped center core region. The process time required may be reduced by using incremental fluorine doping. In the incremental doping process the doping step is separated into a deposit step, where “excess” fluorine is deposited on the silica particles, and a drive-in step where atomic fluorine is distributed into the silica particles. The drive-in step is conveniently combined with the sintering or consolidation step to further enhance the efficiency of the doping process.

Abstract: Embodiments of the invention include a method for making optical fiber having reduced aging or hydrogen aging loss over the life of the fiber and optical fiber systems including such optical fibers. The method includes the steps of dehydrating an optical fiber glass core rod in a first environment including oxygen and at least one of chlorine-containing gases, fluorine-containing gases and carbon monoxide; and adjusting the oxygen stoichiometry of the first environment so that it is neither oxygen-rich nor oxygen-deficient. Improved silicon-oxygen stoichiometry during one or more preform manufacturing steps reduces the amount of Si defects generated in the optical fiber preform. Also, deuterium exposure of optical fiber drawn from the preform reduces the likelihood of having atomic defects such as Si defects in the optical fiber that, over time, attract and bond with hydrogen atoms to form molecules that contribute to increased water absorption loss.

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: Systems and methods are described for fabricating a varying-waveguide optical fiber. In one described method, a preform is fabricated having a core and at least one cladding region. The cladding region has a higher viscosity and the core region has a lower viscosity. The relative viscosities of the cladding region and core are chosen such that, when tension is applied to an optical fiber drawn from the preform, the applied tension is primarily borne by the cladding region thereby causing a viscoelastic strain to be frozen into the cladding region, while creating a minimal viscoelastic strain in the core. The method further includes drawing the preform into an optical fiber under an applied tension, such that a viscoelastic strain is frozen into the cladding region the frozen-in viscoelastic strain decreasing the cladding region refractive index.

Abstract: Burners (14) are used to make glass bodies (19) from OMCTS. The burners have six concentric regions. Putting certain gases through the regions results in thicker bodies than can be achieved with existing techniques and with improved efficiency.

Abstract: Method and burner for increasing the deposition rate of porous glass deposit in the manufacture of optical preforms, by modifying the cross-sectional shape of the flow of glass particles impacting onto a target preform. In particular, the cross-section of the flow of glass particles is modified by increasing the dimension of the flow from a circular cross-section to one having a major and minor axis in a direction substantially perpendicular to the longitudinal axis of the target preform.

Abstract: Multi-flame burner wherein each flame is separated with respect to the neighboring flame by at least one separating tube made of a heat resistant material, for example, quartz glass or ceramic material. The burner also has a plurality of co-axial pipes, preferably made of a metallic material. The cross section of the upper end of the separating tube can be modified in order to increase the deposition rate of the burner. Methods for manufacturing optical fibre preforms by vapour deposition using the multi-flame deposition burners.

Abstract: A method for doping silica soot with fluorine during laydown, including providing a bait rod, and providing a burner, wherein the burner emits a reactant flame. The method also including providing at least one first gas-feed separate from the burner, wherein the gas-feed supplies a first jet of fluorine-based gases, and depositing a layer of silica soot on the bait rod by vaporizing a silica producing gas within the reactant flame of the burner. The method further including supplying the first jet of fluorine-based gases to the silica soot deposited on to the bait rod via the first gas-feed subsequent to vaporizing at least a portion of the silica producing gas within the reactant flame of the burner.

Abstract: The present invention is directed to a system and method for delivering liquid reactants through a burner assembly to form soot used in the manufacture of glass, and in particular, optical waveguides. Due to the tendency of liquid reactants to react to form solids when exposed to water in the air, an evaporative liquid is first delivered through the burner assembly to the combustion zone. Once steady state liquid flow has been achieved in the system, the evaporative liquid is transitioned to the liquid reactant. The liquid reactant is delivered along the same path to the burner assembly, which discharges the liquid reactant into the combustion zone as an atomized liquid to form soot used in the manufacture of glass. Once the desired quantity of soot has been formed, the liquid reactant is transitioned back to the evaporative liquid while maintaining steady state flow. After the liquid reactant has cleared the system, flow of the evaporative liquid is terminated and the burner assembly flame turned off.

Abstract: Burners and methods for producing fused silica members. The burner includes seven gas-emitting regions, including four regions for emitting a mixture of oxygen and combustible gas.

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: A concentric multi-tubular burner for synthesizing glass particles having a center port group constituted by a combination of jet ports of raw material gas, combustible gas and oxygen gas, wherein an outer wall of the oxygen gas jet port in the center port group protrudes more toward a burner head than an inner wall of the oxygen gas jet port. The flow rate of oxygen gas jetted from the oxygen gas jet port of the center port group is controlled to be in a proper range.

Abstract: A double-clad optical fiber includes a core, a multimode inner cladding disposed about the core, and a second cladding layer disposed about the inner cladding. The core includes an active material for absorbing pump radiation received by the inner cladding. The multimode inner cladding includes truncated regions including a first material, where the first material has an index of refraction that is different than the material of the inner cladding that surrounds said truncated regions, for promoting the scattering of pump radiation propagating in the multimode inner cladding for increasing the absorption of the pump radiation by the active material of the core. The truncated regions can include voids that are empty or that comprise a gas. Particles can be distributed in a soot and/or voids formed in the soot, where the soot can be deposited via Outside Vapor Deposition for forming the truncated regions in an optical fiber drawn from a preform.

Abstract: A multi-tube burner is provided which includes a cylindrical outermost nozzle and at least one cylindrical inner nozzle provided coaxially with the outermost nozzle to form annular jet openings for gases used to manufacture a glass preform. The angle between a center axis of an outer circumference of the outermost nozzle and a distal end portion of each of the inner nozzles is 90°± not more than 3°. Furthermore, the distance between the center axis of the outer circumference of the outermost nozzle and each of center axes of inner circumferences and outer circumferences of the inner nozzles is not more than 0.20 mm.

Abstract: To provide an apparatus for manufacturing a glass particles deposit in which it is possible to effectively prevent the foreign matter from being deposited on or mixed into the glass particles deposit during the manufacturing operation. The apparatus for manufacturing the glass particles deposit comprises an upper funnel, a reaction vessel and a lower funnel, wherein the glass particulates are deposited around the outer circumference of a starting rod supported by a support rod within the reaction vessel while the starting rod is being rotated around its axis and reciprocated up and down, characterized in that a sleeve made of quartz separating an inner wall of the reaction vessel and a central rotation member is installed inside the reaction vessel.

Abstract: The present invention provides a method for manufacturing a glass particles deposit body that is formed on the periphery of a starting rod by an OVD method, whereby an optical fiber with enhanced optical transmission characteristics can be produced by reducing the number of disconnections and preventing the alien substances from being mixed into the glass particles deposit body. This invention involves the use of the OVD method in which (1) before or after starting to deposit fine glass particles, a reaction vessel is enclosed to suck and exhaust a gas within the reaction vessel after a removal operation of deposited fine glass particles from the inside of the reaction vessel, (2) when not in operation, a purge gas is passed at a flow rate of 1 m/min or more through each gas line of a burner, (3) when not in operation, a clean air (CA) is introduced into the reaction vessel to make the inner pressure of vessel positive, or (1) and (2) or (1), (2) and (3) are combined.

Abstract: The present invention provides methods for fabricating optical fiber preforms and optical fibers. According to one embodiment of the invention, a method for making an optical fiber preform includes the steps of providing at least one sacrificial rod having an outside surface; forming a material on the outside surface of each sacrificial rod to yield a structured body, the structured body including a structured material in substantial contact with the at least one sacrificial rod; removing each sacrificial rod from the structured body; and including the structured body in the optical fiber preform. The preform may be drawn into an optical fiber. The methods of the present invention are especially useful in the fabrication of microstructured optical fibers.

Abstract: A process for producing synthetic quartz glass using a burner composed of a plurality of concentric nozzles involves the steps of feeding a silica-forming raw material gas and a fluorine compound gas to a reaction zone from a center nozzle, feeding oxygen gas from a second nozzle outside the center nozzle, and feeding oxygen gas and/or hydrogen gas from a third nozzle. The silica-forming raw material gas is hydrolyzed to form fine particles of silica, which particles are deposited on a rotatable substrate so as to form a porous silica matrix, which is then fused to give the quartz glass. The flow rate of the oxygen gas fed from the second nozzle and the flow rate of the raw material gas are controlled so as to provide a 1.1- to 3.5-fold stoichiometric excess of oxygen. The excess oxygen suppresses Si—Si bond formation in the quartz glass, enabling the production of synthetic quartz glass having a high transmittance in the vacuum ultraviolet region.

Abstract: The present invention is directed to methods of producing soot used in the manufacture of optical waveguides. Both non-aqueous liquid reactants and aqueous solutions containing one or more salts are delivered through an atomizing burner assembly to form a homogenous soot stream containing the oxides of the selected elements contained within the non-aqueous liquid reactant and the aqueous solution. The resulting multi-component soot is collected by conventional methods to form preforms used in the manufacture of optical waveguide fibers. Preforms formed by the methods are also disclosed.

Abstract: A method for manufacturing a synthesized silica glass optical member, the method comprising: providing a porous silica glass body; heating the porous silica glass body in an atmosphere containing hydrogen or oxygen, and sintering the porous silica glass body in an atmosphere containing fluorine compound. Furthermore, a synthesized silica glass optical member manufactured by the method.

Abstract: An object of the present invention is to reduce the adhesion of floating glass particulates to the surface of a soot preform during the manufacture of the soot preform, thereby reducing the voids generated in the transparent glass preform made from the soot preform, and to improve the quality of the optical fiber manufactured from the transparent glass preform. The equipment of the invention is equipped with a reaction vessel 1, a burner 2 provided within the reaction vessel 1 into which raw material gas and combustion gas are supplied so as to generate glass particulates by hydrolysis reaction, and a starting rod 5 onto which the glass particulates generated by the burner 2 are deposited. By drawing up the starting rod 5 while turning it around its axis, the glass particulates are deposited on the tip of or around the starting rod 5 to form a soot preform 6 in column-like shape.

Abstract: Embodiments of the invention include a method for making optical fiber having reduced aging or hydrogen aging loss over the life of the fiber and optical fiber systems including such optical fibers. Improved silicon-oxygen stoichiometry during one or more preform manufacturing steps reduces the amount of Si defects generated in the optical fiber preform. Also, deuterium exposure of optical fiber drawn from the preform reduces the likelihood of having atomic defects such as Si defects in the optical fiber that, over time, attract and bond with hydrogen atoms to form molecules that contribute to increased water absorption loss. The inventive method produces optical fibers with improved transmission characteristics, e.g., optical fibers made by methods according to embodiments of the invention have transmission loss at 1385 nanometers that is less than 0.33 dB/km and the aging loss increase thereafter is less than 0.04 dB/km.

Abstract: Methods and apparatus for adding metals such as aluminum to fused silica glass articles are disclosed. The methods and apparatus allow for controlled, low level addition of metals into fused silica glass articles. The fused silica glass articles containing added aluminum exhibit improved internal transmission and decreased absorption change when irradiated with a laser.

Abstract: The present invention is directed to a method and apparatus for forming soot used in making glass, and in particular, optical waveguides. A liquid precursor (66) is first fed into orifice (52) of a liquid orifice insert (48) within an injector (44) positioned within an atomizing burner assembly, and is thereafter discharged from the injector into a pressurization chamber (56). An atomization gas (70) is also fed into the pressurization chamber (56) to mix with the liquid precursor liquid stream (68) which breaks into droplets (76). The liquid precursor and atomization gas arm forced under pressure out of an atomization orifice (32) on the face of the burner (30) assembly. Flame gas (74), reaction gas (84) and shield gas (82) are ejected from burner orifices (40, 38, 36 and 34) to produce the flame.

Abstract: A preform for a low loss fiber optic cable and method and apparatus for fabricating such a preform is provided. The method includes providing AlCl3 and CVD precursors and locally doping CaCl3. Alkali and/or alkaline earth fluxing agents can be introduced. The alkali and/or alkaline earths are doped along with the aluminum into the silica glass core.

Abstract: The invention includes methods of making a fluorine doped soot particle. One method of the invention includes the steps of (1) delivering a silicon containing precursor to a first opening in a burner face; (2) delivering a source of oxygen to a second opening, wherein the second opening is spaced apart from the first opening such that the silicon precursor and oxygen source react to form a soot particle having a surface area of more than about 20 m2/g; and (3) delivering a fluorine precursor to a third opening, said third opening is spaced apart from the first opening. A second method of the invention includes the steps of (A) delivering a silicon containing precursor to a first opening in a burner face; (B) delivering a fluorine precursor to a second opening, wherein said second opening is spaced apart from said first opening; and (C) delivering a fuel to a third opening, said third opening is spaced apart from said first opening.

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: This invention relates to the production of high purity fused silica glass through oxidation or flame hydrolysis of a vaporizable silicon-containing compound. More particularly, this invention is directed to the use of vaporizable, halide-free compounds in said production. In the preferred practice, a polymethylsiloxane comprises said vaporizable, halide-free compound.