Abstract: An apparatus for measuring the weight of a preform for optical fibers during a chemical deposition process for the formation of a preform is disclosed. The apparatus has at least one elastic constraint associated with at least one end portion of an elongated element made of a chemical deposition substrate for the formation of the preform, a device for inducing an oscillation, for example axial, on said elongated element, a device for detecting the frequency of oscillation of said elongated element, and a device for calculating the weight of the preform according to the detected frequency of oscillation. Advantageously, the device allows the realisation of a method for measuring the weight of the preform wherein the errors in measurement caused by thermal drift effects, by the axial distribution of the masses on the preform and by loads which are different from the mass of the preform in formation are reduced to below the required precision in measurement.

Abstract: There is provided a method of manufacturing an optical waveguide, the method including: allowing a beam to be incident in an optical waveguide direction of an optical waveguide material; generating an optical soliton in the optical waveguide material by adjusting intensity of the incident beam according to the optical waveguide material; allowing the incident beam to be re-incident at an intensity higher than an intensity of the incident beam after checking generation of the optical soliton in the optical waveguide material; and increasing a refractive index of an optical soliton-generating area of the optical waveguide material by the re-incident beam to thereby form an optical waveguide.

Abstract: A method of determining a heating amount adequate for fusion splicing is provided. In the method, the melting state of the end portions of optical fibers can be monitored on a real time basis so that fewer tests need to be performed. A method of fusion splicing and a fusion splicer are also provided. In the method of determining the heating amount, end portions of optical fibers that are placed opposite one another with a predetermined gap therebetween are heat-melted; an image of portions to be heat-melted is observed with an image-capturing device; and a luminance, a light emitting width, or a change in the luminance or the light emitting width is measured. In the method of fusion splicing, optical fibers are heat-melted with the heating amount that is determined using test fibers in advance, or determined using the optical fibers to be fusion spliced.

Abstract: A method for producing an optical fiber having low polarization mode dispersion, by the steps of a) providing an optical fiber perform of glass material; b) heating the glass material of an end portion of the optical fiber perform; c) drawing the heated glass material at a drawing speed V to form an optical fiber, the drawn glass material having a viscous zone; and d) applying to the optical fiber a substantially sinusoidal spin, which is transmitted to the viscous zone, the spin function frequency ?, the viscous zone length L and the drawing speed V being such that both a torsion and at least a 50% detorsion are applied to the viscous zone.

Abstract: A method and device for making high precision glass tubes. A glass rod is pushed into a heated chamber and the tube is pulled from the chamber. Preferably, both the push rate and the pull rate are controlled. Fiber optic glass ferrules and other components manufactured by the use of this invention have precision dimensions that fall well within the tight dimensional tolerances required for ferrules and others.

Abstract: A method and apparatus for impulsively spinning optical fiber while the optical fiber is being drawn is disclosed herein.

Abstract: A method of manufacturing mineral fibers includes rotating an orificed spinner and supplying molten mineral material to the spinner to centrifuge streams of molten mineral material. A downward annular flow of attenuating gases is directed to attenuate the streams of molten mineral material into mineral fibers. A mixture of combustion air and combustion gas is supplied to an annular burner positioned around the spinner. Heat from the annular burner is directed toward the spinner and the streams of molten mineral material to heat the spinner and assist in attenuating the streams of molten mineral material into mineral fibers. A pressure sensor senses the pressure of the combustion air prior to the introduction of the combustion air to the burner. The pressure of the combustion air is controlled in response to the sensed pressure to maintain the pressure of the combustion air at a specific pressure.

Abstract: A process for making a non-zero dispersion shifted optical fiber having low splice loss and low attenuation and to an optical fiber produced by this process. A reduction of the splice loss is observed with decreasing drawing tension. The optical fiber has a core region that includes three segments and an inner cladding segment, each having a maximum refractive index percent difference, ?deltai %, i=0-3, the subscript i referring to a particular refractive index, the core segments being selected such that ?delta0%>?delta2%>?delta1%?0 and ?delta2%>?delta3%?0. Optical fibers exhibiting low splice loss were drawn at tensions not larger than 150 g, preferably not larger than 100 g.

Abstract: A method and device for making high precision glass forms (110). A glass rod (1) is pushed into a melting tube (47) and the glass form is pulled from the chamber. Preferably, both the push rate and the pull rate are controlled. Fiber optic glass ferrules and other components manufactured by the use of this invention have precision dimensions that fall well within the tight dimensional tolerances required for ferrules and others.

Abstract: A process for manufacturing an optical fiber, includes the steps of: a) producing a soot core preform by depositing a core material on a substrate; b) removing the substrate from the soot preform leaving an axial cavity along the longitudinal axis of the soot core preform; (c) drying and consolidating the soot core preform so as to obtain a glass core preform having an axial hole corresponding to the axial cavity; d) reducing a diameter of the axial hole; and e) stretching the glass core preform so as to substantially close the axial hole, wherein the process further includes the step of measuring at least one geometric characteristic of the axial hole of the glass core preform.

Abstract: There is provided an elongation method of an optical fiber base material, by which a base material rod not requiring a process for modifying a bend from base material ingot is obtained. The method for elongating base material ingot to be a base material rod having a diameter smaller than before to manufacture an optical fiber base material, includes the steps of: elongating the base material ingot while controlling a control position so that a neck-down within a horizontal surface of the base material ingot is located at a target position; measuring a bending direction and a bending amount of an elongated base material rod; and adjusting the target position based on the result. In addition, it is preferable to adjust a position of a pendant portion of base material ingot in order to control the position of the neck-down to be the target position. For example, the position of the pendant portion may be moved in an XY direction, more particularly, in a direction in which the measured bend shows convexity.

Abstract: A method of producing a glass-particle-deposited body that has a small diameter variation and the like resulting from alteration of the deposition condition is offered. When the glass-particle-deposited body is produced, a burner row constituted by placing a plurality of burners is moved relative to a starting member, and glass particles ejected from the burners are deposited on the starting member. In the method of producing a glass-particle-deposited body, alteration of the deposition condition is performed during the course of the deposition of the glass particles on the starting member. The method of producing a glass-particle-deposited body has a feature in that the alteration of the deposition condition is performed at least twice and that the burner positions along the length of the starting member at which the deposition condition is altered are placed at intervals shorter than the intervals between burners.

Abstract: A drawing method for a bare optical fiber, comprises the steps of: melting an optical fiber preform using a heating device and drawing the bare optical fiber; and naturally cooling down the bare optical fiber or forcibly cooling down the bare optical fiber by a cooling device after the heating and melting step, wherein a temperature history during the drawing the optical fiber preform to obtain the bare optical fiber in the heating device satisfies a relational expression: T??0.01X+12 where a time period when the heated and molten portion of the optical fiber preform heated and molten by the heating device reaches 1800° C. or higher is T (min) and a OH group concentration in a cladding layer of the optical fiber preform is X (wtppm).

Abstract: A preform for forming a hollow-core, slotted photonic band-gap (PBG) optical fiber for use in an environmental sensor, and methods of forming such a fiber using the preform are disclosed. The preform comprises a slotted cladding tube that surrounds a slotted, hollow-core PBG cane. The slots in the cladding tube and PBG cane are longitudinally formed and substantially aligned with each other. When the preform is drawn, the slots merge to form an elongated side opening or slot in the resulting hollow-core PBG fiber. In one case, the slot reaches the hollow core upon drawing, while in another case a second step is used to extend the slot to connect to the hollow core. The fiber is used to form an environmental sensor for sensing the presence of a target substance in an environment. The slot formed in the PBG region of the fiber forms a ridge waveguide wherein a portion of the light that otherwise is confined to the hollow core as a bound mode travels in the slot.

Abstract: The invention relates to a method for producing mineral wool, wherein a mineral base material is melted in a cupola furnace having a shaft to hold the base material, the lower section of said shaft being provided with a grate, and beneath said grate there is a combustion chamber. The combustion chamber is heated by one or a plurality of burners, the burner or burners being run on liquid or gaseous fuel and an oxygen-containing gas. The burners are operated such that the length of the flames occurring during combustion of the fuel with the oxygen-containing gas is between 60% and 100% of the combustion chamber diameter.

Abstract: A method of making optical quality films is described. A silica film is deposited on a wafer by PECVD (Plasma Enhanced Chemical Vapor Deposition). The deposited film is then subjected to a first heat treatment to reduce optical absorption, wafer warp, and compressive stress. A second film is deposited. This step is then followed by a second heat treatment to reduce optical absorption, wafer warp and tensile stress. The two heat treatments have similar temperature profiles.

Abstract: In a known method for producing a cylindrical glass body in a vertical drawing process, a glass blank is softened in a heating zone and drawn off as a glass strand by means of a draw-off device at a controlled drawing speed, the draw-off device comprising a first draw-off unit with rolling bodies rolling on the glass strand and being distributed around the circumference thereof, the rolling bodies being formed by a reference rolling body and at least one auxiliary rolling body, the drawing speed being controlled via the speed of the reference rolling body.

Abstract: Thermal 3-D microstructuring of photonic structures is provided by depositing laser energy by non-linear absorption into a focal volume about each point of a substrate to be micromachined at a rate greater than the rate that it diffuses thereout to produce a point source of heat in a region of the bulk larger than the focal volume about each point that structurally alters the region of the bulk larger than the focal volume about each point, and by dragging the point source of heat thereby provided point-to-point along any linear and non-linear path to fabricate photonic structures in the bulk of the substrate. Exemplary optical waveguides and optical beamsplitters are thermally micromachined in 3-D in the bulk of a glass substrate. The total number of pulses incident to each point is controlled, either by varying the rate that the point source of heat is scanned point-to-point and/or by varying the repetition rate of the laser, to select the mode supported by the waveguide or beamsplitter to be micromachined.

Abstract: A control for a glass forming machine is disclosed which receives as an input the event angles used to control the machines operation. These event angles, which define the time in a cycle when each event is turned on and off, are unwrapped to represent times in the glass forming process which takes more than two machine cycles to complete. A computerized model of the unwrapped cycle is defined and a control analyzes the computerized model as a constrained optimization problem to define an optimized schedule of event times and defines a plurality of intermediate event time schedules in an incremental application.

Abstract: An optical fiber has a section of the first kind having a chromatic dispersion not less than a given positive value x and a negative chromatic dispersion slope at a given wavelength and a section of the second kind has a chromatic dispersion not more than ?x and a positive chromatic dispersion slope at the same wavelength. Another optical fiber has a chromatic dispersion higher than a positive value x and a negative chromatic dispersion slope at a given wavelength band.

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: 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 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 present invention provides an optical device which comprises a light guide incorporating a Bragg grating. The apparatus also comprises a moveable wall portion which is coupled to the Bragg grating so that a movement of the wall portion causes a force that effects a change in strain of the Bragg grating and thereby effects a change in an optical period of the Bragg grating. A temperature related change in the optical period of the Bragg grating is reduced by a temperature related change in the force on the Bragg grating by the moveable wall portion.

Abstract: A method of determining parameters of plurality of thermal cycles to achieve a set glass strain level includes providing a plurality of input parameters for a glass substrate and a plurality of parameters for a plurality of thermal cycles. The method also includes iteratively modifying at least one of the pluralities of thermal cycle parameters so the glass strain is not greater than the set glass strain level after a final thermal cycle is completed. An aspect of the method usefully enables a user to determine from the material parameters and processing sequences of the glass manufacturer and further entities that may further process the glass (e.g., the glass manufacturer's customers) whether a particular glass strain can be achieved; and if not the example embodiments allows the manufacturer to calculate changes in the customers' processes to meet the desired glass strain.

Abstract: The invention relates to a method and apparatus for monitoring safety glass production or controlling a treatment process, such as a tempering process. Information representing a load of glass panels is used in controlling a treatment process, such as heating of glass panels, or in monitoring production. The information, which includes at least one of the following: shape, size, and position, is read with one or more cameras (6). This is possible as glass is made visible by means of reflected light as high intensity light is applied to the glass surface. The line camera (6) is used for receiving low intensity background light radiation incident through the glass conveying plane, a substantial increase in its intensity, as light is reflected by glass, being deciphered as glass.

Abstract: A glass body with at least one curve is formed from a glass blank in bar form in a bending device for bending the glass blanks. The bending device has grippers which are movable in relation to one another. The glass blank is taken up by the grippers and clamped. Subsequently, the bending region between the grippers is heated up to a bending temperature by heating means. After that, the grippers are moved in a predetermined way, the bending region being freely bent. The advantageous effects of the invention are seen as being that any desired curves can be produced on glass blanks without requiring moulds that rely on pressing or contact. The free bending takes place without touching the surface in the heated-up bending region, so that instances of damage to the surface are avoided. This allows curved glass bodies with good optical properties to be produced.

Abstract: Methods are disclosed herein for joining a first optical fiber and a second optical fiber, wherein at least one of the first and second optical fibers has an annular glass region, such as a cladding, which is provided with a plurality of holes. The methods are well suited for joining a first microstructured optical fiber, such as a first optical fiber having a plurality of holes having a maximum cross-sectional diameter on the order of 7 microns or less, to another second optical fiber. The second optical fiber could be another microstructured optical fiber or a non-microstructured optical fiber.

Abstract: A method of manufacturing an optical fiber preform by passing a porous glass preform through a heating area in an atmosphere of dehydration gas to dehydrate the porous glass preform is provided. Values Pcl and V are set and dehydration is performed to satisfy 0.0773×e7.4873×??Pcl×T×L/V according to ?, T, and L, where Pcl is a partial pressure of chlorine gas in the dehydration gas, T is a process temperature, L is a length of an area in the heating area where a temperature is 1150° C. or higher, V is a relative moving speed of the porous glass preform with respect to the heating area, and ? is an average bulk density of a porous glass layer.

Abstract: An optical fiber drawing installation is equipped with an oscillating pulley that applies torsion to the fiber alternately in one rotation direction and then in the opposite direction. To control the torsion applied to the fiber, images are formed of the fiber and the pulley. The images are analyzed to determine the position of the fiber relative to the pulley. The torsion is calculated from the calculated position, on the assumption that the fiber rolls on the pulley.

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: A process and apparatus for elongating an optical fibre preform includes heating the preform so as to soften one region thereof; elongating the preform by submitting the preform to a traction; determining, during the step of elongating, the preform diameter in at least one measuring point along the preform; and controlling the step of elongating on the basis of the determined diameter. During the step of elongating, at least a geometrical parameter of the preform is measured, and the position of said diameter measuring point is controlled according to the measured geometrical parameter. Measuring at least a geometrical parameter of the preform may be accomplished by determining the profile of at least a portion of the softened region, e.g., an image of the neck region profile.

Abstract: There is provided robust diameter-controlled optical fiber during optical fiber drawing process and an optical fiber drawing process which comprises drawing the optical fiber from a perform therefor under tension to form the optical fiber while heating and melting the preform, wherein an outer diameter of the preform is measured (at a safe position immediately) above the furnace, an outer diameter of the optical fiber on which no coating has been provided is measured at one process position or two process positions before coating, and drawing conditions are robustly controlled based on the deviation of the measured optical fiber diameter data and the measured preform diameter data from a preselected outer diameter of the optical fiber and a preselected outer diameter of the preform.

Abstract: To provide a method for producing a glass particle deposit and a method for producing a glass preform, in which outer diameter variation of the glass particle deposit can be reduced to thereby improve quality. A flow rate of clean gas (CG) introduced into a container potion 10 is limited to thereby prevent the outermost layer of a glass particle deposit 20 from being locally cooled and reduce variation in bulk density in the longitudinal direction of the glass particle deposit 20, that is, outer diameter variation and breakage.

Abstract: An optical fiber characterized by a cutoff wavelength of 1310 nm or less, a transmission loss of 0.40 dB/km or less at the wavelength of 1385 nm before hydrogen ageing, a transmission loss of 0.40 dB/km or less in the wavelength range of 1310 nm to 1625 nm after hydrogen ageing, and an electron spin density of the Non-Bridging Oxygen Hole Center of 1×1013 spins/g or less measured by the electron spin resonance method after the diameter of the optical fiber is made to be about 50 ?m by etching in diluted hydrofluoric acid, that having high reliability of hydrogen-proof characteristic suitable for WDM transmission in 1310 nm to 1625 nm and the method of evaluating the optical fiber are offered.

Abstract: An apparatus for manufacturing a glass base material, which is a base material of an optical fiber, comprising: a base rod, around and along which said glass base material is formed; a burner that hydrolyzes and accumulates a gas material, which is a base material of said glass base material, around and along said base rod; a first burner-moving-unit that moves said burner in a direction parallel with a longitudinal direction of said base rod; and a second burner-moving-unit that moves said first burner-moving-unit in a same moving direction of said first burner-moving-unit.

Abstract: A roll coater for placing binder on the fibers prior to being wound around a rotating drawing drum. The drawing drum draws fibers out of orifices in the bottom of a slowly reciprocating furnace. The fibers form a mat on the drawing drum that is later removed and expanded. The roll coater includes a graphite or other material coating drum that rotates in a bath of liquid binder and/or wetting agents, and reciprocates with the furnace. The fibers scrape over the surface of the coating drum after being formed but before winding around the drawing drum. The binder and/or wetting agent picked up on the surface of the coating drum coats the fibers with binder and/or wetting agent. Liquid binder and/or wetting agent is replenished in the bath in which the coating drum is partially submerged by a float, sensor, pump and large container of binder/wetting agent.

Abstract: According to a prior art method for producing a cylindrical component comprised of silica glass, a cylinder comprised of a softened silica glass mass is drawn in a predetermined drawing direction along a drawing axis by means of a drawing device which acts upon said cylinder. The aim of the invention is to provide a method which prevents, to the greatest possible extent, warping of the drawn cylinder and other deviations from the ideal cylinder dimensions and to prevent, to the greatest possible extent, the outer surface of the drawn cylinder from being touched. To these ends, the invention provides that the drawing device comprises a plurality of guide elements which are arranged one behind the other along the drawing axis, and which can be displaced independently of one another in a drawing direction and in a direction opposite thereto.

Abstract: Methods and apparatuses estimate and control optical fiber primary coating diameter for wet-on-wet optical fiber manufacturing. The primary coating diameter for a particular length of optical fiber is calculated based upon a measurement of the weight of primary and/or secondary coating material consumed during optical fiber manufacturing. Control of the primary coating diameter is effected by a coating controller which can increase or decrease the primary coating diameter through control of glass temperature, coating viscosity and/or other parameters during wet-on-wet fiber manufacture.

Abstract: An optical fiber, and a method of making such optical fiber, wherein the optical fiber exhibits a beatlength greater than about 5 meters, and the fiber is spun to provide a polarization mode dispersion in the spun state of said fiber which is less than 0.05 ps/km1/2. The fiber is spun by employing a spin having a spin repeat distance of at least 10 meters. The spin preferably alternates between clockwise and counterclockwise directions.

Abstract: An optical fiber splicing method is provided for largely reducing an optical loss in a splice and eliminating a varying outer diameter and bending deformation. This splicing method splices opposing end faces of two optical fibers by fusion, and heats a formed fusion splice to match mode field diameters of the two optical fibers in the fusion splice, wherein the two optical fibers are fixed with an axial tension applied or not applied to the fusion splice, after the formation of the fusion splice, before the fusion splice is heated.

Abstract: A method for manufacturing optical fiber with enhanced photosensitivity comprising the step of: forming a molten layer of glass and drawing a fiber from the molten layer of glass at a temperature of between about 1900° C. and 1995° C. Draw tension can be adjusted to attain the desired draw speed.

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: A method for fabricating a GRIN fiber includes forming a tube of silica-glass having a tubular core and a concentric tubular cladding adjacent and external to the tubular core. The core has a dopant density with a radially graded profile. The method includes partially collapsing the tube by applying heat thereto. The partially collapsed tube has a central channel. The method includes passing a glass etchant through the central canal to remove an internal layer of silica glass, and then, collapsing the etched tube to a rod-like preform.

Abstract: A coolant system for cooling a fiber includes a heat exchanger with an internal passage disposed between a fiber inlet and fiber outlet to cool the fiber moving through the internal passage. A plurality of chambers are disposed within the internal passage, and at least one fluid medium flows within at least a portion of the internal passage, and at least one adjustable seal is positioned within the internal passage to form a partition between two adjacent chambers. A gas analyzer communicates with at least one chamber of the internal passage to extract a fluid sample from the chamber and to measure a concentration of a gas in the extracted fluid sample. A controller communicates with the analyzer and controls at least one of the adjustable seal and the flow rate of fluid medium within the internal passage based upon the measured concentration.

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

Abstract: A method of measuring optical fiber-drawing tension, containing: measuring oscillation of an optical fiber when drawing; determining a fundamental oscillation frequency of the optical fiber based on peak frequencies contained in spectrum components of oscillation waveform; and converting the fundamental oscillation frequency into tension applied to the optical fiber being drawn; wherein the determination of the fundamental oscillation frequency is performed through specifying, as a harmonic oscillation series group, a group of peak frequencies containing at least two peak frequencies, in which an interval between zero (0) and first peak frequencies, an interval between first and second peak frequencies, . . . , and an interval between (n−1)th and nth peak frequencies (where n is a natural number) are equal to each other, from among the peak frequencies in the spectrum components, to carry out the method based on the peak frequencies in the specified harmonic oscillation series group.

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

Abstract: A method of manufacturing a micro molten glass droplet, has the steps of, colliding a molten glass droplet with a micro through hole formed in a plate-shaped member; and pushing out at least part of the glass droplet to a reverse surface of the micro through hole as a micro droplet, thereby forming a glass droplet with a diameter of not more than 5 mm.

Abstract: A fiber drawing method according to the present invention is a drawing method of optical fiber for drawing an optical fiber 14 from one end of a fiber preform 13 by softening with heat, wherein the fiber preform 13 is set in a semi-closed space 10, 20 opening in part at a lower end in a fiber drawing furnace, the fiber preform 13 is heated by a heater 15 disposed on the lower end side of this semi-closed space 10, 20, and fiber drawing is carried out with adjusting a quantity of heat dissipation from the upper portion 20 of this semi-closed space.

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.