Abstract: A deposition system for depositing a chemical vapor onto a workpiece is disclosed, including a deposition chamber having a plurality of components for performing chemical vapor deposition on the workpiece. The workpiece is held by a lathe that rotates the workpiece relative to chemical burners that deposit silica soot on the workpiece. The deposition system 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. Multiple sets of chemical burners are disposed longitudinally along the length of the workpiece. Each set of burners is separated from other sets, such that each set of burners deposit silica particles onto generally different portions of a workpiece. The respective portions include an overlap segment in which one or more burners from one burner set will deposit silica particles on the same portion of the workpiece as one or more burners from another set.

Abstract: On an EUV light-reflecting surface of titania-doped quartz glass, an angle (?) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

Abstract: An optical fiber comprising a first core, a second core, a third core, and a cladding, wherein with a refractive index of the cladding as a reference, ?1 is a maximum value of a relative refractive index difference of the first core, ?2 is a maximum value of a relative refractive index difference of the second core, ?3 is a minimum value of a relative refractive index difference of the third core, “a” is a half-value radial width for the relative refractive index difference (?1??2) of the first core, “b” is a radius of a second core/third core boundary, and “c” is a radius of a third core/cladding boundary, the expressions 0.30%??1?0.45%, ?0.05%??2?0.05%, ?0.6%??3??0.3%, 2.85?b/a, 10 ?m?b?15 ?m, and 3 ?m?c?b?5.5 ?m are satisfied, and transmission loss for a wavelength of 1550 nm when the optical fiber is wound around a mandrel with a diameter of 10 mm is no greater than 0.2 dB/turn.

Abstract: Methods are described for manufacturing silica-based glass, in which silica precursor material is supplied to a synthesis flame in the form of an emulsion. The methods involve the steps of: forming an emulsion of an aqueous phase in a non-aqueous liquid silica precursor material; supplying the emulsion as a spray of droplets into a synthesis flame, whereby the precursor material is converted in the flame into a silica-containing soot; and collecting the soot on a substrate, either as a porous soot body for subsequent consolidation to glass or directly as a substantially pore-free glass.

Abstract: A low attenuation single mode optical fiber includes a core layer and claddings. The core layer has the relative refractive index difference (RRID) ?1 ranging from ?0.1% to +0.1% and the radius R1 ranging from 4.0 ?m to 6.0 ?m. The claddings have three claddings layers surrounding the core layer. The RRID of the first cladding layer ?2 ranges from ?0.2% to ?0.6%, and the radius R2 thereof ranges from 10 ?m to 22 ?m. The RRID of the second cladding layer ?3 is less than ?2. The RRID and radius of the first cladding layer and the RRID and radius of the second cladding layer satisfy the relationship of: V=(?2??3)×(R3?R2), and the value of V ranges from 0.15% ?m to 0.8% ?m. The third cladding layer is all the layers that closely surround the second cladding layer, and the RRID of each layer is greater than ?3.

Abstract: A method of manufacturing quartz glass includes depositing soot generated by flame hydrolysis of a raw material gas to a starting member, while the starting member is raised and rotated, to form a soot deposition member that includes an effective portion having a substantially constant outer diameter, the effective portion to become a material of a glass product, an upper ineffective portion formed at an upper end of the effective portion, and a lower ineffective portion formed at a lower end of the effective portion, each of the ineffective portions having an outer diameter changing in a tapering form, wherein the depositing includes forming the lower ineffective portion while decreasing a peripheral speed of a surface of the starting member to a predetermined final peripheral speed in a ratio of 1.3 m/minute or below per second during a period after the effective portion is formed.

Abstract: A method of manufacturing an optical fiber preform by depositing glass fine particles onto a surface of a glass rod while the glass rod is reciprocated relative to a plasma torch, including: moving the glass rod in a first direction relative to the plasma torch while the plasma torch is applied to the glass rod and supplied at least with a dopant material and a glass material to deposit the glass fine particles onto the surface of the glass rod, in such a manner that a plasma power is set higher during a first time interval starting from a beginning of the movement of the glass rod in the first direction than during a second time interval starting from an end of the first time interval; and moving the glass rod in a second direction relative to the plasma torch, where the second direction is opposite to the first direction.

Abstract: Described is a modular method of making an optical fiber comprising a core and a cladding configured to support and guide a fundamental transverse mode, the cladding including (i) an outer cladding having an index nout less than the index n1 of the core, (ii) an inner cladding having an index n2<nout, (iii) a pedestal having an index n4?nout, (iv) an inner trench disposed between the inner cladding and the pedestal, the inner trench having an index n3<<n4, and (iv) an outer trench disposed between the pedestal and the outer cladding, the outer trench having an index n5<n4 and relatively close to nout. To suppress unwanted HOMs the pedestal is configured to resonantly couple at least one unwanted transverse mode of the core (other than the fundamental mode) to at least one transverse mode of the pedestal.

Abstract: A known refraction-sensitive optical fiber comprises a core zone with an index of refraction nK, a jacket zone surrounding the core zone, said jacket zone having an index of refraction nM, and an annular zone made of quartz glass doped with fluorine, said annular zone surrounding the jacket zone and having an index of refraction nF, where nF<nM<nK. With this as a starting point, an optical fiber is to be provided that is characterized by high refraction-sensitivity, good spliceability and compatibility, and a method is to be provided for cost-effective manufacture of such a fiber. With regard to the method, this object is accomplished according to the invention in that the quartz glass of the annular zone (21) is produced in a plasma deposition process on the outside in which an annular zonal layer made of the quartz glass doped with fluorine is produced on a substrate body (20), said layer having a layer thickness of at least 1 mm and an index of refraction nF<1.

Abstract: A method for manufacturing an optical fiber preform includes a process A of applying flame polishing to a center glass rod, a process B of determining a ratio ra/rb, which is a ratio of a radius ra of the center glass rod expressed in millimeters with respect to a radius rb of a target optical fiber preform expressed in millimeters, based on a refractive index profile of a target optical fiber preform, and a process C of determining an amount of fine glass particles to be deposited on the center glass rod so that a ratio ra/rb/c falls within a range from 0.002 to 0.01, where “c” is a maximum value of hydroxyl group concentration expressed in ppm in the vicinity of a boundary between the center glass rod and an outer layer, which is formed by depositing fine glass particles on the center rod and by being vitrified.

Abstract: A method is provided for forming an optical fiber amplifier. The method comprises providing a composite preform having a gain material core that includes one or more acoustic velocity varying dopants to provide a longitudinally varying acoustic velocity profile along the gain material core to suppress Stimulated Brillouin Scattering (SBS) effects by raising the SBS threshold and drawing the composite preform to form the optical fiber amplifier.

Abstract: A method of manufacturing an optical waveguide preform includes providing a first process gas atmosphere to a soot preform contained in a vessel. The first atmosphere is held in the vessel for a first reacting time sufficient to at least partially dope or dry the soot preform. The vessel is then at least partially refilled with a second doping or drying atmosphere. The second doping or drying atmosphere is held in the vessel for a second reacting time sufficient to further dope or dry the soot preform.

Abstract: A method for fabricating a porous silica preform includes the steps of supplying fuel gas for generating an oxyhydrogen flame to a glass synthesizing burner; supplying Gas A containing silicon and Gas B containing fluorine to the burner; synthesizing glass particles; and depositing the glass particles around a starting rod, in which when glass particles are deposited directly on the starting rod, a supply of Gas A and a supply of Gas B supplied to the burner are adjusted so that a ratio of the number of fluorine atoms to the number of silicon atoms in the gas supplied to the burner satisfies the following Formula (1): {(number of F atoms)/(number of Si atoms)}?0.1 ??(1).

Abstract: A method of fabricating an optical fiber preform that can give stable and high deposition efficiency from the start to the end of the deposition when synthesizing a large size preform. When fabricating a preform by hydrolyzing a glass raw material gas in flame to generate glass particles and depositing the glass particles on a rotating starting material in the radial direction using a burner with a concentric multiple-tube structure having at least a plurality of small diameter combustion assisting gas-ejecting ports having the same focal length. L1 is made greater than L2 (L1>L2) during an early stage of deposition and L2 is increased in the course of the deposition so that L2 is greater than L1 (L1<L2), where the focal length is denoted by L1 and the distance from the tip of the burner to a deposition plane on the starting material is denoted by L2.

Abstract: A method of making an optical fiber preform includes depositing silica glass soot on the inside of a substrate tube via a chemical vapor deposition operation. The silica glass soot is consolidated into silica glass under controlled conditions such that the consolidated silica glass on the interior of the substrate tube contains a non-periodic array of gaseous voids in a cladding region of the optical fiber preform. The optical fiber preform may be used to produce an optical fiber having a core and a cladding containing voids formed from the gaseous voids of the cladding region of the optical fiber preform. The core of the optical fiber has a first index of refraction and the cladding has a second index of refraction less than that of the core.

Abstract: A lens unit (20) includes a lens body (24) and a thin film (22) provided thereon. The thin film comprises a plurality of sections (220, 222, 224) from a center to a periphery. Each section has a different refractive index. The refractive index of the each section of the thin film increases from the center to the periphery of the lens body/thin film. Such a lens unit can be advantageously incorporated into a compact digital camera.

Abstract: An optical fiber is formed by performing vapor phase deposition of SiO2 on the outside of a glass rod comprising a core section and a first cladding section and drawing a glass preform which formed by a second cladding section. Also, a single mode optical fiber is manufactured so that the ratio of the diameter D of the first cladding section and the diameter d of the core section is in a range of 4.0 to 4.8, and OH concentration is 0.1 ppm or less. Also, an optical fiber is manufactured so that a value of D/d>4.8, and the OH concentration is 0. 1 ppm or less. It is thereby possible to maintain an initial loss in the 1380 nm wavelength range even if hydrogen diffusion occurs.

Abstract: The present invention relates to a method of manufacturing an optical fibre suitable for high transmission rates, which method comprises: i) supplying one or more glass forming precursors, and possibly a dopant, to a quartz substrate tube, ii) forming a plasma in the quartz substrate tube for the purpose of bringing about a reaction mixture so as to form glass layers, which may or may not be doped, on the interior of the substrate tube, iii) collapsing the substrate tube obtained in step ii) into a perform while heating, and iv) drawing an optical fibre from the perform while heating. The present invention furthermore relates to an optical fibre suitable for high transmission rates.

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: The present invention provides an optical fiber preform manufacturing method and a burner apparatus employed for this method. In this manufacturing method, when glass particles are synthesized in an oxy-hydrogen flame emitted from a burner to form a porous optical fiber preform by depositing glass particles in the radial direction of a starting member, the relationship between the flow rate vm (m/sec) of a source material gas or a mixed gas of the source material gas and an additive gas discharged from the burner, and the flow rate vs (m/sec) of an inert gas is such that ?0.06 vm+1.4?vs??0.02 vm+1.8, and vs?0.40, while the relationship between the flow volume Vm (1/min) of the source material gas discharged from the burner and the flow volume Vs (1/min) of the inert gas is such that Vs/Vm?0.2.

Abstract: An optical fiber and an optical fiber preform having optical characteristics, such as the wavelength dispersion, close to design values by controlling the amount of change in the refractive index in the core, thereby realizing high-quality and high-speed transmission, and manufacturing methods therefor. The optical fiber or the optical fiber preform is manufactured in a manner such that at each position in the area in which the relative refractive index of the core with respect to the cladding is 80% or higher of the maximum value of the relative refractive index, the absolute value of the rate of change of the relative refractive index with respect to the position along the diameter of the cladding is 0.5 or less, where the position along the diameter of the cladding is defined by percentage with respect to the diameter.

Abstract: A GRIN fiber lens is fabricated by the steps of providing a graded index glass preform, thinning the graded index preform to remove a sufficient thickness of the graded glass to establish a desired ?n, and drawing a graded index optical fiber from the thinned graded index preform. Thinning, in this context, refers to removal of graded index glass from the outside of the graded index preform so as to reduce its outer diameter. The thinning thus changes ?n which is the refractive index difference between the center of the preform and its outer surface. The graded index preform can be provided by MCVD deposition followed by removal of the starting tube glass, by OVD deposition, by VAD, or by ion exchange fabrication. The thinned graded index preform is advantageously annealed before drawing in order to minimize ripple. And, in a variation of the process, an overcladding can be applied over the thinned graded preform before draw for further adjustment or control of the ?n.

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: A method and apparatus for forming a glass article such as an optical fiber having a substantially matching viscosity across an interface associated with a first section and a second section of the optical fiber is disclosed herein. The first section has a first halogen concentration and the second section has a second halogen concentration. At least one of a partial pressure of the second halogen provided to a substrate tube and a temperature of the substrate tube is configured to affect the concentration of the second halogen in the second section. Optical fiber embodiments are also included.

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: 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: 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: The present invention relates to a multimode fiber having a refractive index profile, wherein the area surrounding the center of the fiber has a refractive index profile such that the responses of a DMD (Differential Mode Delay) measurement carried out on a fiber having a length of at least 300 m are obtained without any pulse splitting occurring in the center of the fiber.

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: 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: 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 GRIN fiber lens is fabricated by the steps of providing a graded index glass preform, thinning the graded index preform to remove a sufficient thickness of the graded glass to establish a desired &Dgr;n, and drawing a graded index optical fiber from the thinned graded index preform. Thinning, in this context, refers to removal of graded index glass from the outside of the graded index preform so as to reduce its outer diameter. The thinning thus changes &Dgr;n which is the refractive index difference between the center of the preform and its outer surface. The graded index preform can be provided by MCVD deposition followed by removal of the starting tube glass, by OVD deposition, by VAD, or by ion exchange fabrication. The thinned graded index preform is advantageously annealed before drawing in order to minimize ripple. And, in a variation of the process, an overcladding can be applied over the thinned graded preform before draw for further adjustment or control of the &Dgr;n.

Abstract: A method for producing a porous preform comprising measuring the surface temperature distribution at the end of the core soot preform, and (1) maintaining the surface temperature Tc at the center point on the end of the core soot preform in the range of 500 to 1000° C., and preferably in the range of 600 to 950° C.; and maintaining the difference Tm−Tc between the maximum surface temperature Tm at the end of the core soot preform and the surface temperature Tc at the center point on the end of the core soot preform in the range of 5 to 45° C.; and/or (2) maintaining the ratio R of the area in which the surface temperature at the end of the core soot preform is higher than the surface temperature Tc at the center point on the end of the core soot preform in the range of 5 to 30%.

Abstract: A method for manufacturing a base material of optical fibres having a desired ratio of core to clad, including forming a porous base material upon depositing glass particles, producing a core member upon dehydrating and vitrifying the porous base material, adding a clad member onto the core member, is characterized in that the method includes, a step of dehydrating the porous base material in an atmosphere of gas including helium and chlorine within an electric furnace; a step of vitrifying the porous base material in an atmosphere of inert gas including helium; and a step of providing a purging step of heating the porous base material in an atmosphere of inert gas mainly including helium between the dehydrating step and the vitrifying step.

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: In an optical fiber of this invention, the MFD is increased to effectively suppress the influence of nonlinear optical effects. A method of manufacturing the optical fiber effectively prevents bubble occurrence in a transparent preform, deformation of the preform, and flaws on the preform surface during the manufacture. The optical fiber has, from its center to the peripheral portion, a first core having a first refractive index n1, a second core having a second refractive index n2 (<n1), a first cladding having a third refractive index n3 (<n2), and a second cladding having a fourth refractive index n4 (>n3, <n2). The outer diameter of the second core is set to be 25 to 40 &mgr;m. Specifically, the refractive indices of the first and second claddings of the optical fiber preferably increase in the radial direction from the inner side thereof to the peripheral side thereof.

Abstract: A method and apparatus are disclosed for the manufacture of an optical fiber preform having incorporated therein a comparatively high concentration of rare earth dopant material, and which thus can be drawn and processed into an optical fiber having low numerical aperture, low core attenuation, and high pumping power absorption. The high concentrations of rare earth dopant material are accomplished through either the “hybrid vapor processing” (HVP) method or a “hybrid liquid processing” (HLP) method, each capable of being practiced in combination or independently of one another. The HVP method involves the vaporization of a rare earth halogen by the exposure thereof to a sufficiently elevated temperature, independently, or contemporaneously with the transport of the resultant rare earth halogen laden vapor, into a glass forming oxidation reaction zone on a flowing stream of essentially an unreactive inert gas, such as helium.

Abstract: The present invention relates to a single-mode optical fiber having a configuration which enables lowering of dispersion slope while securing a sufficient MFD. This single-mode optical fiber has a refractive index profile in which an indent with a sufficient width is provided at the center of its core region.

Abstract: The present invention discloses novel methods for fabricating glass articles, particularly optical fiber glass preforms, which may contain alumina, yttrium, lanthanum, erbium, or other rare earth metals as dopants. The glass articles made in accordance with the present invention exhibit radially uniform dopant profiles relative to conventional dopant methods. In addition, the overall concentration of the dopant is increased relative to analogous dopant methods.

Abstract: A method of forming a silica soot preform comprising: forming a primary soot preform on an outer periphery of a glass rod by a primary burner; and forming a secondary soot preform by a secondary burner on an outer periphery the primary soot preform, wherein a diameter of the primary soot preform is set to be ranged from twice to five times of a diameter of the glass rod, a thickness of the secondary soot preform is set to be range from 1.5 times to seven times of that of the primary soot preform. Consequently, the deposition rate with respect to the introduction of the raw material gas is considerably increased. Further, it is possible to maximize a performance of depositing the primary soot preform.

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: 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 comprisses 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 reduced dispersion optical waveguide and methods of fabricating the same are implemented. The optical waveguide may be fabricated in commercially practicable units without having to predetermine its length in a particular application. The reduced dispersion optical waveguide prevents optical pulse overlap in optical waveguide transmission systems operating over long distances or at high data rates.

Abstract: Methods, systems, and apparatus consistent with the present invention apply one or more laser beams to a glass object, such as a tube. The beams may have differing wavelengths, energy levels, and/or focal length characteristics. As the beam (single or multiple) penetrates the glass tube, it creates a channel. The beam is provided through the channel to a starting point on a region of the glass tube, usually the region below an inside diameter surface of the tube. In one embodiment, the beam is used to selectively heat a reactant gas within the tube to deposit a coating/dopant layer on the inside diameter surface. In another embodiment, the coating layer is already present and the beam selectively heats the layer causing thermal diffusion of the coating material into the glass tube at the region being heated.

Abstract: There is disclosed a method of constructing photosensitive waveguides on silicon wafers through the utilization of a Plasma Enhanced Vapor Deposition (PECVD) system. The deposition is utilized to vary the refractive index of resulting structures when they have been subject to Ultra Violet (UV) post processing.

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: A method of manufacturing synthetic silica glass includes the steps of pressurizing a liquid storage tank including a liquid silicon compound therein, generating bubbles in the liquid silicon compound using a foamer, removing the bubbles using a degasser, displacing the liquid silicon compound into a vaporizer while controlling an amount of the liquid silicon compound displaced by a liquid mass flow meter, mixing the displaced liquid silicon compound with a carrier gas to generate a gaseous silicon compound, injecting the gaseous silicon compound into a synthesis furnace, and forming synthetic silica glass by hydrolyzing the gaseous silicon compound in the synthesis furnace.

Abstract: The present invention relates to a single-mode optical fiber having a configuration which enables lowering of dispersion slope while securing a sufficient MFD. This single-mode optical fiber has a refractive index profile in which an indent with a sufficient width is provided at the center of its core region.