Abstract: A single mode optical fiber is provided that includes a core region having an outer radius r1 and a maximum relative refractive index ?1max. The single mode optical fiber further includes a cladding region surrounding the core region, the cladding region includes a depressed-index cladding region, a relative refractive index ?3 of the depressed-index cladding region increasing with increased radial position. The single mode optical fiber has a bend loss at 1550 nm for a 15 mm diameter mandrel of less than about 0.75 dB/turn, a bend loss at 1550 nm for a 20 mm diameter mandrel of less than about 0.2 dB/turn, and a bend loss at 1550 nm for a 30 mm diameter mandrel of less than 0.005 dB/turn. Additionally, the single mode optical fiber has a mode field diameter of 9.0 microns or greater at 1310 nm wavelength.

Abstract: According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.

Abstract: Preparation of halogen-doped silica is described. The preparation includes doping silica with high halogen concentration, sintering halogen-doped silica to a closed-pore state, and subjecting the closed-pore silica body to a thermal treatment process and/or a pressure treatment process. The temperature of thermal treatment is sufficiently high to facilitate reaction of unreacted doping precursor trapped in voids or interstices of the glass structure, but is below temperatures conducive to foaming. Core canes or fibers drawn from halogen-doped silica subjected to the thermal treatment and/or pressure treatment show improved optical quality and possess fewer defects. The thermal treatment and/or pressure treatment is particularly advantageous when used for silica doped with high concentrations of halogen.

Abstract: An optical fiber production system is provided which includes a slow-cooling device and a purge device positioned above the slow-cooling device. The purge device includes a tube defining an inlet. An optical fiber extends through the slow-cooling device and the purge device. The purge device is configured to inject a purge gas through the inlet and against the optical fiber.

Abstract: Disclosed is a vaporizable substance application tool having an integrated ideal temperature indicator. In one embodiment, an apparatus includes an applicator, a thermocouple, and a temperature indicator. The applicator is positioned on a first end of the apparatus to apply a vaporizable substance onto a heatable surface. The thermocouple is positioned on a second end of the apparatus. The temperature indicator is positioned between the applicator and the thermocouple. In addition, the temperature indicator of the apparatus visually indicates different temperature states. In a first state, a background of the temperature indicator illuminates in a first color when the temperature is below an ideal range. In a second state, the background of the temperature indicator illuminates in a second color when the temperature is within the ideal range. In a third state, the background of the temperature indicator illuminates in a third color when the temperature exceeds the ideal range.

Abstract: An optical fiber comprises, from a center to a periphery, a fiber core of undoped silica; a cladding layer; and a coating of polyacrylate, wherein the fiber core has a radius of 5 to 7 ?m and an ellipticity of less than 1.5%, the cladding layer with an ellipticity of less than 0.4% comprises inner, intermediate, and outer cladding layers, the inner cladding layer being doped with fluorine of 5 to 12 ?m thickness, and refractive index difference to fiber core of ?0.4 to ?0.2%, the outer cladding layer being undoped quartz of 25 to 45 ?m thickness, and the coating comprises an inner coating of 25 to 40 ?m thickness, and an outer coating of 25 to 35 ?m thickness and an ellipticity of less than 2%. The optical fiber has high durability and large effective transmission area, a method and system for preparing such optical fiber are also disclosed.

Abstract: According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.

Abstract: A production method of an optical fiber preform includes: forming a porous preform by depositing silica particles at an outer periphery of a core rod; and vitrifying the porous preform by conducting thermal treatment steps. At a first thermal treatment step that is an initial thermal treatment step of the thermal treatment steps, the porous preform is heated so that internal temperatures at two end portions in a longitudinal direction of the porous preform increase before an internal temperature of a center portion in the longitudinal direction increases.

Abstract: Disclosed herein are various embodiments of coil transducers configured to provide high voltage isolation and high voltage breakdown performance characteristics in small packages. A coil transducer is provided through and across which data or power signals may be transmitted and received by primary and secondary coils disposed on opposing sides thereof without high voltage breakdowns occurring therebetween. A central core layer separates the transmitting and receiving coils, and has no vias disposed therethrough. At least portions of the coil transducer are formed of an electrically insulating, non-metallic, non-semiconductor, low dielectric loss material.

Abstract: A method of making optical fibers that includes controlled cooling to produce fibers having a low concentration of non-bridging oxygen defects and low sensitivity to hydrogen. The method may include heating a fiber preform above its softening point, drawing a fiber from the heated preform and passing the fiber through two treatment stages. The fiber may enter the first treatment stage at a temperature between 1500° C. and 1700° C., may exit the first treatment stage at a temperature between 1200° C. and 1400° C., and may experience a cooling rate less than 5000° C./s in the first treatment stage. The fiber may enter the second treatment stage downstream from the first treatment stage at a temperature between 1200° C. and 1400° C., may exit the second treatment stage at a temperature between 1000° C. and 1150° C., and may experience a cooling rate between 5000° C./s and 12,000° C./s in the second treatment stage.

Abstract: Provided is a method for producing an optical fiber having low attenuation and including a core that contains an alkali metal element. An optical fiber preform that includes a core part and a cladding part is drawn with a drawing apparatus 1 to form an optical fiber 30, the core part having an average concentration of an alkali metal element of 5 atomic ppm or more and the cladding part containing fluorine and chlorine. The optical fiber includes a glass portion and resin coating portion and the glass portion is under residual stress that is a compressive stress of 130 MPa or less. During the drawing, the time during which an individual position of the optical fiber preform is maintained at 1500° C. or higher is 110 minutes or less.

Abstract: An optical fiber end processing method includes the steps of: an optical fiber fixing step of fixing two parts of the optical fiber; a first heating step of heating a tip end side part of the optical fiber between two fixed parts fixed in the optical fiber fixing step, and melting the optical fiber of the tip end side heating part; a second heating step of heating a part on a base end side of the optical fiber between the fixed parts away from the tip end side heating part in a state that two parts of the optical fiber are fixed, and making the holes of the optical fiber disappear; and a removing step of removing the tip end side heating part after the second heating step.

Abstract: In the method for manufacturing a glass-fine-particle-deposited body according to the present invention, at least a part of a gas supplying pipe 25 from a temperature controlled booth 24 to a burner 18 for cladding is temperature-controlled so that the temperature at the burner side becomes high and temperature gradient becomes 5° C./m or more. The temperature control is performed so that the temperature gradient becomes preferably 15° C./m or more, more preferably 25° C./m or more. Specifically, the part is controlled to the predetermined temperature gradient by winding a tape heater 26 that is a heating element on the outer circumference of the gas supplying pipe 25 from the temperature controlled booth 24 to the burner 18 for cladding and temperature-controlling the tape heater 26.

Abstract: A method for using a temperature control loop in order to further develop process control during elongation of a cylindrical preform such that a component strand with high dimensional accuracy can be drawn even in the presence of temperature-effective defects during the elongation process: (a) the continuous measurement of a first temperature value, Ttop, at an upper measuring point on the surface of the cylindrical preform; (b) the continuous measurement of a second temperature value, Tbottom, at a lower measuring point; (c) calculation of a temperature distribution in the region between the measuring points Ttop and Tbottom, and determination of a modelled deformation temperature, Tmodel, using an algorithmic model taking with first and the second temperature values as model input parameters, and the modelled deformation temperature, Tmodel, as a regulating variable and the heating-zone temperature Toven as a manipulated variable for the temperature-control loop.

Abstract: A resistive heating element is used to fabricate a long-period grating mode converter. The resistive heating element creates a localized heating zone for creating an asymmetric perturbation at a periodic series of axial locations along the length of a segment of optical fiber that supports the propagation of both a symmetric mode and an asymmetric mode. In a further technique, a grating is written with an index contrast value that is higher than a selected optimum value. The heating element is then used to anneal the fiber segment so as to reduce the contrast value of the grating to the selected optimum value.

Abstract: A method for manufacturing a primary preform for optical fibres including surrounding at least part of a hollow substrate tube with a furnace set at a temperature T0, supplying doped or undoped gases to the inside of the tube, creating a reaction zone to promote deposition, and moving the zone back and forth along the length of the tube between to form at least one preform layer, wherein the temperature of the furnace is varied linearly as a function of the thickness of the at least one preform layer to compensate for temperature increases of the tube during deposition.

Abstract: A method for producing a glass fiber, through longitudinally drawing a preform in a drawing kiln, wherein cooling the glass fiber is performed in at least three time periods, wherein the glass fiber is exposed to a first time based cooling rate above a crystallization temperature range, to a second time based cooling rate that is greater than the first time based cooling rate within the crystallization temperature range, and to a third time based cooling rate which is smaller than the second time based cooling rate below the crystallization temperature range.

Abstract: Provided is a method for manufacturing an optical fiber that is inserted into an insertion portion of an endoscope and guides light, wherein inside an upright fiber drawing furnace, inside a hollow clad tube including a clad glass having a viscosity ?1 of 5.0<Log ?1<7.0 at a temperature at which a viscosity ?2 of a core glass becomes Log ?2=3.5, the core glass in a fluidized state runs down by gravity, whereby the core glass and the clad glass are integrated.

Abstract: A method of producing an optical fiber preform by heating a glass preform that has a glass rod and a silica glass porous body and includes a valid portion and invalid portions, comprising: heating the glass preform while moving the glass preform along its axial direction relative to a heater; stopping the relative movement or decreasing a speed of the relative movement when an invalid portion positioned at a tail end reaches a vicinity of the heater; heating the invalid portion for a predetermined time while maintaining a temperature at which the silica glass porous body can be vitrified; decreasing the heating temperature to a temperature determined by adding 200° C. to an annealing point of a silica glass; and removing the glass preform to the outside of the heating furnace without increasing the heating temperature to the temperature at which the silica glass porous body is vitrified.

Abstract: The method of manufacturing porous glass base material for optical fiber includes that flame-hydrolyzing raw materials for glass in oxyhydrogen flame, depositing the generated glass fine particles on a rotating target to form porous glass base material, dehydrating and sintering the porous glass base material to transform into clear glass. The method features, in terms of the surface temperature of said porous glass base material, which changes as the burner used for depositing glass fine particle is moved relatively to said target, the temperature difference between the surface temperature of the porous glass base material touching the burner flame Ta and the surface temperature of the porous glass base material before touching the flame Tb, that is Ta?Tb, is adjusted to be within the range from 200 to 700 degrees centigrade.

Abstract: A method of manufacturing a holey fiber includes forming a preform and drawing the preform. The forming includes arranging a core rod at a center of a jacket tube and arranging capillary tubes having hollows around the core rod inside the jacket tube. The drawing includes heat melting the preform in a heating furnace while controlling at least one of a gas pressure to be applied to insides of the hollows of the capillary tubes, a temperature of the heating furnace, and a drawing speed, based on a structure of air holes to be formed in a first layer from the core region.

Abstract: The invention relates to a method for manufacturing an optical fiber, wherein a preform is placed in a draw tower, which draw tower comprises a furnace in which one end of a preform is heated, after which an optical fiber is drawn from the heated end, wherein the heating and/or cooling of the draw furnace takes place with a maximum temperature gradient of 15° C./minute.

Abstract: A method for producing a glass fiber, through longitudinally drawing a preform in a drawing kiln, wherein cooling the glass fiber is performed in at least three time periods, wherein the glass fiber is exposed to a first time based cooling rate above a crystallization temperature range, to a second time based cooling rate that is greater than the first time based cooling rate within the crystallization temperature range, and to a third time based cooling rate which is smaller than the second time based cooling rate below the crystallization temperature range.

Abstract: A method for forming an optical fiber includes drawing the optical fiber from a glass supply and treating the fiber by maintaining the optical fiber in a treatment zone wherein the fiber is cooled at a specified cooling rate. The optical fiber treatment reduces the tendency of the optical fiber to increase in attenuation due to Rayleigh scattering, and/or over time following formation of the optical fiber due to heat aging. Methods for producing optical fibers along nonlinear paths incorporating fluid bearings are also provided thereby allowing for increased vertical space for the fiber treatment zone.

Abstract: A splicer comprises a positioning device, in which the fiber ends in general have a residual offset. A memory stores a predetermined relationship between the possible offset and a parameter which controls the application of heat. The parameter which controls the application of heat, for example the splicing time for a predetermined splicing current, is defined on the basis of an actual offset which can be recorded by means of cameras.

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: In a glass processing method according to the invention, in the case of performing chemical vapor deposition or diameter shrinkage of a substrate glass tube G by relatively moving a heating furnace 20 comprising a heating element 21 for annularly enclosing the circumference of the substrate glass tube in a longitudinal direction of the substrate glass tube G with respect to the substrate glass tube G in which an outer diameter is 30 mm or more and a wall thickness is 3 mm or more and is less than 15 mm and an ovality of the outer diameter is 1.0% or less using a glass processing apparatus 1, a temperature of at least one of the heating element 21 and the substrate glass tube G is measured and the amount of heat generation of the heating element 21 is adjusted based on the measured temperature.

Abstract: A method of making an optical fiber preform includes depositing silica glass on the inside of a tube substrate via a plasma chemical vapor deposition (PCVD) operation. The parameters of the PCVD operation are controlled such that the silica glass deposited on the interior of the tube substrate contains a non-periodic array of 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 void containing cladding. 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: In a glass processing method according to the invention, in the case of performing chemical vapor deposition or diameter shrinkage of a substrate glass tube G by relatively moving a heating furnace 20 comprising a heating element 21 for annularly enclosing the circumference of the substrate glass tube in a longitudinal direction of the substrate glass tube G with respect to the substrate glass tube G in which an outer diameter is 30 mm or more and a wall thickness is 3 mm or more and is less than 15 mm and an ovality of the outer diameter is 1.0% or less using a glass processing apparatus 1, a temperature of at least one of the heating element 21 and the substrate glass tube G is measured and the amount of heat generation of the heating element 21 is adjusted based on the measured temperature.

Abstract: According to an embodiment of the invention a method of manufacturing optical fiber cane comprises the steps of: (i) providing a core rod manufactured of relatively low viscosity glass; (ii) depositing SiO2 based soot around the core rod to form a soot preform, the soot being of relatively high viscosity material such that the softening point of the low viscosity glass is at least 200° C. lower than the viscosity of the high viscosity outer core region; and (iii) consolidating the soot of the soot preform by exposure to hot zone at temperatures of 1000° C.-1600° C. The soot is consolidated by heating the outer portion of the soot preform at a relatively fast heating rate, the heating rate being sufficient to densify the soot, so as to render the densified material with enough rigidity to confine the heated core rod and to prevent the heated core rod from puddling.

Abstract: A double-clad optical fiber fabrication method including the steps of: preparing a crystal fiber, inserting the crystal fiber into a silica capillary, attaching a sapphire tube to the periphery of the silica capillary, and applying a laser beam to the sapphire tube to increase the temperature of the sapphire tube and to further fuse the silica capillary with thermal radiation to have the fused silica capillary be wrapped about the crystal fiber, thereby forming the desired double-clad optical fiber.

Abstract: An object is to provide a readily fusible glass fiber composition that can alleviate environmental problem and reduce raw material cost by decreasing boron content, and that can facilitate the manufacturing of fine-count glass filament. A glass fiber composition of the present invention is an oxide glass composition, and has compositions of 0.01 to 3% of P2O5, 52 to 62% of SiO2, 10 to 16% of Al2O3, 0 to 8% of B2O3, 0 to 5% of MgO, 16 to 30% of CaO, and 0 to 2% of R2O(R?Li+N+K), which are in terms of oxide represented in mass percentage.

Abstract: Various embodiments of the present invention relate to glass fiber forming bushings, to methods of controlling the temperature of bushings having multiple segments, to systems of controlling the temperature of bushings having multiple segments, and to other systems and methods. In one embodiment, a method of controlling the temperature of a bushing having multiple segments comprises forming a plurality of filaments from a bushing comprising at least two segments, gathering the filaments into at least two ends, measuring the size of each of the at least two ends, comparing the measured size of the at least two ends to a desired end size, adjusting the amount of current passing through the at least two bushing segments in response to the end size comparisons.

Abstract: A method and apparatus for measuring the insertion loss of a fiber optic connection is provided. The invention generally comprises a light source providing light to a test connector which contains a juncture of two fiber optic cables. The test connector has one or more opaque portions surrounding the fiber optic juncture. A pyrometer or other heat detection means is then used to measure any temperature increase as a result of light scattered into the opaque portions of the test connector.

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: Inorganic fiber production processes and systems are disclosed. One process includes providing a molten inorganic fiberizable material, forming substantially vertical primary fibers from the molten material, and attenuating the primary fibers using an oxy-fuel fiberization burner. Other processes include forming a composition comprising combustion gases, aspirated air and inorganic fibers, and preheating a fuel stream and/or an oxidant stream prior to combustion in a fiberization burner using heat developed during the process. Flame temperature of fiberization burners may be controlled by monitoring various burner parameters. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: Apparatus for forming fibres or flakes of material comprises means (1) for producing a heated stream of molten material (9), means for feeding the stream in a substantially vertically downward direction and means (7) for receiving the downwardly directed stream and for forming fibres or flakes therefrom. The apparatus includes means (11, 13, 15, 17) for effecting a change in the temperature of the stream subsequent to the production thereof whereby fibres or flakes of a desired thickness are obtained. Instead of, or in addition to, the temperature changing means, there may be provided means for controlling the mass or volume flow of the stream. The invention also provides methods corresponding to the apparatus.

Abstract: Methods for substantially improving the stability of a melting furnace system including bushings and cooling apparatus for converting molten mineral material to continuous fibers is disclosed. Apparatus and methods for maintaining the molten material throughput and the electrical power load on fiberizing bushings substantially constant are disclosed. The orifice plate, with or without tips or nozzles, is subjected to a more rapid rate of heat removal after the bushing breaks out than it did while the bushing was in a desired fiberizing mode. Apparatus for blowing cooling air upward onto the orifice plate during the time the bushing is breaking out and/or hanging to provide additional cooling is disclosed along with optional additional or alternative apparatus to use for optional additional or alternative cooling is also disclosed.

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 method of producing an optical fiber preform by heating a glass preform that has a glass rod and a silica glass porous body and includes a valid portion and invalid portions, comprising: heating the glass preform while moving the glass preform along its axial direction relative to a heater; stopping the relative movement or decreasing a speed of the relative movement when an invalid portion positioned at a tail end reaches a vicinity of the heater; heating the invalid portion for a predetermined time while maintaining a temperature at which the silica glass porous body can be vitrified; decreasing the heating temperature to a temperature determined by adding 200° C. to an annealing point of a silica glass; and removing the glass preform to the outside of the heating furnace without increasing the heating temperature to the temperature at which the silica glass porous body is vitrified.

Abstract: In a glass processing method according to the invention, in the case of performing chemical vapor deposition or diameter shrinkage of a substrate glass tube G by relatively moving a heating furnace 20 comprising a heating element 21 for annularly enclosing the circumference of the substrate glass tube in a longitudinal direction of the substrate glass tube G with respect to the substrate glass tube G in which an outer diameter is 30 mm or more and a wall thickness is 3 mm or more and is less than 15 mm and an ovality of the outer diameter is 1.0% or less using a glass processing apparatus 1, a temperature of at least one of the heating element 21 and the substrate glass tube G is measured and the amount of heat generation of the heating element 21 is adjusted based on the measured temperature.

Abstract: The invention relates to a method for the economic production of a blank for a component made from laser-active quartz glass in any form or dimension. The method comprises the following method steps: a) preparation of a dispersion with a solids content of at least 40 wt. %, comprising SiO2 nanopowder and doping agents, including a cation of the rare earth metals and transition metals in a fluid, b) granulation by agitation of the dispersion, with removal of moisture to form a doped SiO2 granulate of spherical porous granular particles with a moisture content of less than 35 wt. % and a density of at least 0.95 g/cm3, c) drying and purification of the SiO2 granulate, by heating to a temperature of at least 1000° C. to form doped porous SiO2 grains with an OH content of less than 10 ppm and d) sintering or fusing the doped SiO2 grains in a reducing atmosphere to give the blank made from doped quartz glass.

Abstract: In the jointing method of jointing an optical fiber F a softening point of which is higher than an optical lens L to the optical lens L, only the optical lens is softened by heating, and an end face as a joint portion of the optical fiber is pushed into a joint portion of the softened optical lens to thereby joint them.

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: A method for forming an optical fiber includes drawing the optical fiber from a glass supply and treating the fiber by maintaining the optical fiber within a treatment temperature range for a treatment time. Preferably also, the fiber is cooled at a specified cooling rate. The optical fiber treatment reduces the tendency of the optical fiber to increase in attenuation due to Rayleigh scattering, and/or over time following formation of the optical fiber due to heat aging. Apparatus are also provided.

Abstract: A pressure detecting unit detects a pressure of supplying a resin to at least a hole for forming an innermost resin layer on an optical fiber from among a plurality of successive holes in a coating die. A control unit controls a discharge amount of a constant-rate pump that supplies the resin to the coating die in such a manner that a detected resin pressure becomes a predetermined value, and controls a temperature of the optical fiber so that the temperature of the optical fiber becomes a predetermined temperature in accordance with a variation of the discharge amount of the constant-rate pump.

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 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: The present invention provides an optical synthetic quartz glass material which substantially does not cause changes in transmitted wave surface (TWS) by solarization, compaction (TWS delayed), rarefaction (TWS progressed) and photorefractive effect when ArF excimer laser irradiation is applied at a low energy density, e.g. at energy density per pulse of 0.3 mJ/cm2 or less. The present invention further provides a method for manufacturing the same. In order to solve the above-mentioned problems, the optical synthetic quartz glass material of the present invention is characterized in that, in a synthetic quartz glass prepared by a flame hydrolysis method using a silicon compound as a material, the followings are satisfied that the amount of SiOH is within a range of more than 10 ppm by weight to 400 ppm by weight, content of fluorine is 30 to 1000 ppm by weight, content of hydrogen is 0.

Abstract: An apparatus for producing an optical fiber preform to perform the deposition process by modified chemical vapor deposition. The Apparatus comprises a main heat source location sensor (800) for detecting the location of a main heat source for heating a substrate tube 100, an additional supporting device control part (1000) wiredly or wirelessly connected to the main heat source location sensor (800), and an additional supporting device (1100) wiredly or wirelessly connected to the additional supporting device control part (1000) for supporting the substrate tube (100). The present invention reduces the effective length of the substrate tube (100) by additionally supporting the substrate tube (100), thereby minimizing the deflection of the substrate tube (100). Particularly, it is possible to considerably reduce the deflection of the substrate tube at its initial part and thus to achieve a high deposition efficiency. Accordingly, it is possible to mass-produce an optical fiber preform of high quality.