Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5,5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5,5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5,5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5,5′) which are below the separating plates (4, 17) and adapted to blow an inert gas into the inner tubes (5,5′) and the muff

Abstract: A method of protecting a silica-containing article used in the manufacture of an optical fiber includes the step of applying to the silica-containing article a protective layer that facilitates removal of particulates that deposit on the protective layer and that ablates during or can be removed before subsequent processing of the silica-containing article. An intermediate product used in the manufacture of an optical fiber and protected against break-inducing particulates includes a silica-containing article, and a protective layer that facilitates removal of particulates-that have deposited on the protective layer and that can be ablated during or removed before subsequent processing of the intermediate product.

Abstract: A method for the pregobbing of an optical fiber preform to provide pre-optimized tip taper and system for drawing optical fiber therefrom. The downtime of an optical fiber drawing apparatus can be considerably shortened, by providing preforms that have a pre-optimized tip shape. Pre-optimized tips are provided which are melted off at the tip by an induction heater of a heating furnace. Preferably, the pregobbing furnace has substantially the same temperature profile as the draw furnace. Therefore, because the tip of the preform is optimized and unusable glass has been removed, throughput of the draw apparatus is advantageously increased. Moreover, the shape of the tip of the preform is optimized in that it has been exposed to the same temperature profile as it would have seen had the draw tip been formed in the draw furnace.

Abstract: A method of protecting a silica-containing article used in the manufacture of an optical fiber includes the step of applying to the silica-containing article a protective layer that facilitates removal of particulates that deposit on the protective layer and that ablates during or can be removed before subsequent processing of the silica-containing article. An intermediate product used in the manufacture of an optical fiber and protected against break-inducing particulates includes a silica-containing article, and a protective layer that facilitates removal of particulates that have deposited on the protective layer and that can be ablated during or removed before subsequent processing of the intermediate product.

Abstract: The invention is directed to the production of optical fibers from optical fiber preforms using flow physics. The present methods provide for the “drawing” of an optical fiber preform using focusing of the preform by a surrounding fluid, e.g. a heated gas.

Abstract: Based on an intermediate 20A in which a cladding portion 22 is formed on the outer periphery of a core portion 21, a pair of holes 23 and 24 are provided parallel to the z axis on both sides of the core portion 21 within the cladding portion 22, and an intermediate 20 is thereby fabricated. In this intermediate 20, a width Ry in the y-axis direction is made smaller than a width Rx in the x-axis direction. Moreover, a cylindrical stress applying part 33 is inserted into a hole 23 of the intermediate 20, and a cylindrical stress applying part 34 is inserted into a hole 24 thereof. Thus, a preform 40 is formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.

Abstract: A furnace is provided. The furnace includes a chamber for heating a portion of a preform to draw a fiber. The chamber has a melt region for melting the preform, and at least one port disposed proximate to the melt region. A purge gas supply is provided for supplying a purge gas into the chamber. The purge gas moves vapor products away from the fiber and exits the chamber through the at least one port.

Abstract: In a method of fabricating an optical fiber comprising a silica-based glassy material deuterium is injected in a fiber drawing device. Defect centers generated during the fiber drawing are occupied by deuterium atoms.

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: A method of manufacturing a silica-containing article used in the manufacture of an optical fiber includes the steps of applying to the silica-containing article a protective layer, and then transporting the coated article to a second factory for further processing. The layer facilitates ease of removal of particulates that deposit on the protective layer. The layer preferably ablates during, or can be readily removed subsequent to, further processing of the silica-containing article. Any intermediate product used in the manufacture of an optical fiber, for example, a core blank, core cane segment, consolidated preform, etc. may be readily shipped between various factories because the articles are protected against break-inducing particulates by the protective layer.

Abstract: Embodiments of the invention include a method and apparatus for making optical fiber preforms and optical fiber. The method includes the steps of positioning an overclad tube around a preform core rod, heating the overclad tube along the length thereof in the presence of a pressure gradient to collapse onto the preform core to form the overclad optical fiber preform, and adjusting the radial size of a heated portion of the preform core rod and/or the overclad tube to actively match the radial dimensions of the preform core rod along the length thereof with corresponding portions of the overclad tube. The active matching reduces variations in the physical dimensions of the preform core rod and/or the overclad tube, which improves transmission and other performance characteristics of fiber drawn from the created preform, e.g., by maintaining a relatively constant D/d ratio of the preform.

Abstract: An apparatus for drawing an optical fiber and a method for controlling the feed speed of an optical fiber preform whereby the drawing speed of an optical fiber is stabilized to keep the size of the outer diameter uniform. The capstan speed is determined based on the outer diameter of the optical fiber. When the capstan speed is out of a target speed range, the preform feed speed is controlled to bring the capstan speed into the target range. A control unit includes a calculation unit for receiving a drawing speed signal output from the capstan and calculating a feed speed of the perform. The control unit regulates the outer diameter of the optical fiber by regulating the speed of the capstan according to a signal received from the outer diameter measurement unit indicating a change in the outer diameter of the optical fiber.

Abstract: An end heating and processing method of an optical fiber preform. In this method, an optical fiber preform is processed by heating and melting an end of a vitrified optical fiber preform including a core portion and a cladding portion formed on an outer circumference thereof to process the end having a shape for drawing as an optical fiber.

Abstract: The glass base material drawing apparatus for heating and drawing a glass base material has a storage unit for storing the glass base material having an opening unit that is opened along the longitudinal direction of the storage unit when the glass base material is placed inside the storage unit, a heating unit for heating the glass base material that has been stored inside the storage unit via the opening unit, and a pull-out unit for pulling out the glass base material heated by the heating unit. The opening unit may be opened in such a manner that the glass base material is moved from a side direction of the storage unit into the interior of the storage unit. A main axis for supporting the glass base material is connected to the glass base material. The storage unit may have a penetration hole through which the main axis is inserted when the opening unit is closed.

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

Abstract: Disclosed is a multiple core optical waveguide fiber having a negative total dispersion and negative total dispersion slope tailored to compensate the total dispersion of a typical high performance transmission fiber over a selected wavelength range. Also disclosed is a method of making the multiple core optical waveguide fiber and a compensated link using the multiple core fiber. The simplicity of the refractive index profiles of the constituent cores provides ease of manufacture of the multiple core structure.

Abstract: Apparatus and methods allow fused bi-conical couplers to be pulled to reduced diameters to exposes more of the evanescent field in the coupled region. First and second stages hold the fibers on either side of the fused region, with at least one of the stages being moveable relative to the other. A furnace positioned relative to the fused region, and a tensometer is used to determine the tension of the fibers between the stages. A controller is provided to monitor the tension on the fibers and increase the distance between the stages when the tension falls to a predetermined threshold. As the fibers are pulled, light begins to couple from one fiber to the next, leading to five distinct crossover regions. The tension is continuously monitored, and when the tension drops below each threshold, the furnace is slowly pushed back to maintain the tension by decreasing the heat on the fiber from the furnace. As the fiber is pulled through these crossover areas, the coupling region decreases in diameter.

Abstract: A method for fusing an optical fiber preform comprises fusing the preform while blowing an oxidative gas against the preform to be fused from upper and lower directions of a fusing burner unit. An apparatus for carrying out the method includes a plurality of nozzles for preventing deposition of silica cloud, which are each set at an angle, &thgr;, of blowing the oxidative gas relative to the preform being drawn such 20°≦&thgr;≦60°.

Abstract: The present invention provides for an apparatus and method to manufacture optical fiber in a way that produces controlled and patterned diffusion of optical radiation along its length. The novelty of the described invention is that the patterns of diffusion are produced at the time the optical fiber is manufactured. The “in-line” manufacturing method avoids the need for post-production treatment of the fiber, which makes the process highly efficient and economical. Light diffusing optical fibers of significant length can be produced. Several manufacturing configurations to achieve the desired effects and their inclusion in the fiber production process are described. The processes can be configured to process optical fibers constructed from a wide variety of known glass, polymeric or other materials. The partially diffusing optical fibers of this invention have applications ranging from illuminated fabrics and toys and to lighting systems and medical instruments.

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: A method of cooling an optical fiber while it is being drawn through contact with at least one cooling fluid in at least one cooling area, wherein said method is such that fast cooling, i.e. cooling that is faster than cooling in the surrounding air, is followed by slow cooling, i.e. cooling slower than cooling in the surrounding air, the temperature of the fiber in an intermediate area between the two cooling areas lying in the range 1200° C. to 1700° C. in the case of silica glass fibers.

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

Abstract: A method of cooling an optical fiber during drawing through contact with at least one cooling fluid in at least one cooling area, wherein fast cooling, i.e. cooling that is faster than cooling in the surrounding air, from an initial temperature of the fiber to a temperature at the end of fast cooling of said fiber, is followed by slow cooling, i.e. cooling slower than cooling in the surrounding air, from a temperature of said fiber at the start of slow cooling to a temperature of said fiber at the end of slow cooling.

Abstract: Disclosed is a multi-line optical fiber drawing equipment, wherein at least two strands of optical fibers can be simultaneously drawn by the single draw tower, thereby maximizing an effectiveness of an installation space for a draw tower and the productivity in drawing the optical fiber. The optical fiber multi-line drawing equipment has at least two lines for drawing optical fibers from preforms. Each of the lines has a chuck, a furnace, a cooling unit, a coating unit, a curing unit, and a capstan, which are arranged in sequence in a draw tower. Processes for drawing optical fibers from preforms respectively along the lines are simultaneously performed.

Abstract: The soliton pulse compression optical fiber comprises a core and a clad that surrounds the core for compressing the injected light pulse in width. The maximum relative index difference between the core and the clad is between about 1.2% and 2.5%. The core diameter of the soliton pulse compression optical fiber varies along the length of the soliton pulse compression optical fiber and the core has a step-like refractive index distribution. The optical fiber perform of the soliton pulse compression optical fiber comprises a core preform, which is to be a core of the soliton pulse compression optical fiber, and a clad preform that surrounds the core preform. The maximum relative index difference between the core perform and the clad preform is also between about 1.2% and 2.5%.

Abstract: The invention describes a procedure for manufacturing photonic crystals and passive and active optoelectronic device components comprising of photonic crystals. The manufacturing approach draws upon the mature technology of producing microchannel plates (MCPs). Based on this manufacturing approach, photonic crystal structures with or without defects can be fabricated. The photonic band gaps produced in the presented invention can be made passive or active. A photonic crystal structure is described that contain different photonic band gap regions. Additionally, photonic crystal structures filled with different refractive indexes are described. The photonic crystals of the present invention maybe used as filters, phase shifters, splitters, couplers, multiplexers, demultiplexers, modulators, variable optical attenuators, gain equalizers, etc. for optical communication applications.

Abstract: The present invention provides a method for manufacturing a photonic crystal fiber that has a core portion in which a fiber core extends in a lengthwise direction and is formed as a solid or a void, and a porous clad portion provided around the core portion and having numerous pores extending along the core portion. A preform is fabricated by packing numerous capillaries into a cylindrical support pipe such that they are parallel to the central axis of the support pipe and disposing a core rod to serve as the solid core portion at the central axis portion of the support pipe. The preform is drawn to make it small in diameter.

Abstract: High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.

Abstract: An optical component and a method of making the same are provided. In one embodiment, the optical component is a low-OH optical fiber that includes a core and a cladding. The optical component is treated by immersion in a hydrogen gas atmosphere at a predetermined pressure, at a predetermined temperature and for a predetermined time period such that intrinsic and impurity defects of the optical component are destroyed. The method of making the optical component includes providing a preform having a content of OH-groups in the amount of about 0.1 to about 10.0 ppm and a content of chlorine in the amount of 0 to about 1000 ppm and drawing the preform to elongate it to form an optical component from the preform. The optical component is immersed in a hydrogen gas atmosphere at a predetermined pressure, at a predetermined temperature and for a predetermined time period that is sufficient to destroy intrinsic and impurity defects of the optical component.

Abstract: High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.

Abstract: In a known method for the manufacture of a tube made of a vitreous material, especially of quartz glass, a hollow cylindrical semifinished product made of a vitreous material is carried essentially vertically to a heating zone, wherein it is heated and drawn off downwards—without the use of tools—to the tube by forming a transitional area from semifinished product to tube, while diameter and wall thickness of the tube are continuously measured, and the tube's measured geometrical data being used to generate a control signal with the aid of which a pressure difference is regulated between pressure P1 in the interior space of the semifinished product, the transitional area and the tube, as well as pressure P2 in the heating chamber which is regulated in the heating zone at least in the transitional area from semifinished product to tube and its adjacent tube area.

Abstract: The present invention relates to an optical fiber fabrication method by which an optical fiber having an objective chromatic dispersion characteristic can be obtained readily. In an optical fiber fabrication method, a cutoff wavelength is measured in an optical fiber with a fixed length obtained by first drawing a part of an optical fiber preform. A target glass diameter for yielding an objective chromatic dispersion characteristic is then determined based on the cutoff wavelength thus measured. Then the rest of the optical fiber preform is drawn so that the glass diameter becomes the target glass diameter thus determined, thereby fabricating the optical fiber.

Abstract: The method of manufacturing an optical fiber in accordance with the present invention comprises a step of yielding an optical fiber by drawing an optical fiber preform softened upon heating, wherein a temperature at which the optical fiber preform is softened is at least 1800° C., whereas the optical fiber preform or optical fiber has a glass cooling rate of 4000° C./sec or less when attaining a temperature of 1800° C.

Abstract: A method of making a phosphosilicate fiber comprises the steps of: (i) manufacturing a preform containing phosphorus doped silica; and (ii) drawing phosphosilicate fiber from said preform at a temperature in the range of 1700° C. to 1900° C.

Abstract: A method of fabricating an optical waveguide fiber from a preform having a centerline hole which includes pressurizing and expanding the centerline hole to improve uniformity, circularity, and/or symmetry of hole closure in order to achieve low levels of polarization mode dispersion in the fiber.

Abstract: This invention relates to production of high purity fused silica glass doped with titania using titanium chelates. Useful chelates include titanium acetylacetonate, and titanium ethyl acetoacetate among others.

Abstract: The drawing method of the present invention uses a drawing furnace comprising a furnace muffle tube, a furnace body and a heater. According to the method, an optical fiber preform is inserted from the inlet of the furnace muffle tube, the optical fiber preform is melted by means of a heater, under a specified gas atmosphere, and is drawn toward the outlet of the furnace muffle tube by means of a specified drawing tension.

Abstract: A core glass for making a preform for an optical fiber particularly useful for the transmission of ultraviolet radiation and methods for making the core glass are disclosed. The core glass is obtained by the flame hydrolysis of a silicon compound, deposition of finely granular SiO2 on a substrate with direct vitrification and formation of a synthetic quartz glass. The quartz glass has a hydrogen content of less than 1×1018 molecules/cm3.

Abstract: Disclosed is a method of producing an elliptic core optical fiber, in which a original preform having a circular core disposed at the center of a circular clad is processed to flatten on its periphery to form a processed preform that is then drawn with heating into an elliptic core optical fiber.

Abstract: The invention relates to a device for drawing optical fibers from a preform, comprising: a furnace comprising a tube for heating one end of said preform to the drawing temperature thereof, which tube comprises: i) a central tube, ii) an upper extension tube connected to the lower part of said central tube so as to obtain a gas tight seal against an ambient atmosphere exterior said furnace, wherein the upper extension tube comprises an inlet for an inert gas in the top region of the upper extension tube, as a result of which the preform and the fiber to be drawn therefrom are surrounded by an inert gas, iii) a lower extension tube connected to said upper extension tube in such a manner that a gas tight seal against an ambient atmosphere exterior said furnace is obtained, iv) a tube outlet connected to said lower extension tube, means for drawing the fiber, means for supporting the preform in the furnace.

Abstract: A multimode optical fiber having a first laser bandwidth greater than 220 MHz.km in the 850 nm window, a second laser bandwidth greater than 500 MHz.km in the 1300 nm window, a first OFL bandwidth of at least 160 MHz.km in the 850 nm window, and a second OFL bandwidth of at least 500 MHz.km in the 1300 nm window is disclosed. The multimode fiber is capable of operating in telecommunication systems employing both LED power sources and high power laser sources. Methods of making and testing the multimode optical fiber are also disclosed.

Abstract: Embodiments of the invention include a method and apparatus for making a multiple overclad optical fiber preform. The method includes positioning a first overclad tube around a preform core rod, positioning at least one second overclad tube around the first overclad tube, and collectively heating the preform core and the overclad tubes under pressure to collapse the overclad tubes onto the preform core rod thus producing a multiple overclad optical fiber preform. The apparatus includes a preform core rod, a first overclad tube surrounding the preform core rod, and at least one second overclad tube surrounding the first overclad tube. A quartz disc with or without one or more quartz spacers is used for supporting the preform core rod and the first overclad tube within the additional overclad tubes.

Abstract: The present invention provides a polarization maintaining optical fiber of which polarization crosstalk characteristic is not deteriorated after fusing two or more polarization maintaining optical fibers, and provides a method for producing a preform thereof. The polarization maintaining optical fiber includes two stress applying portions disposed in a cladding around a core, in which an angle formed by a line connecting the center of one of the stress applying portions with the center of the core and a line connecting the center of the other stress applying portion with the center of the core is 3 degrees or less. The preform is produced by forming one insertion hole in a cladding element and then rotating the preform 180 degrees around a core element without moving the drilling tool, followed by forming the other insertion hole in the cladding element and then inserting stress applying elements into the insertion holes.

Abstract: A method for producing a large quartz glass preform for optical fibers having a low ellipticity at a low cost is provided. The method comprises a heating and stretching of a large quartz glass cylinder or a preform in which a core rod is inserted in said quartz glass cylinder without being integrated with the cylinder in non-contact state, using a heating furnace equipped with a carbon-made heating element, whereby setting the ratio (d/D) of the outer diameter (D) of the large quartz glass cylinder and the inner diameter (d) of the heating element to a range of from 1.02 to 1.5, and blowing in an inert gas from the upper part of the heating furnace (FIG.

Abstract: Provided is an optical fiber having holes extending along the axis whose transmission loss is substantially reduced and the manufacturing method thereof. First, a plurality of through-holes 9 are formed in a preform 5 extending along the preform axis. Subsequently, the preform 5 is heated by heating means 24 in the furnace preferably for 30 minutes or more at a temperature equal to or more than 800° C. while flowing a dry gas in the through-holes 9. As a result, the OH group which exists on the surfaces of the inner walls 5a of the through-holes 9 of the preform 5 is discharged outside the preform. Subsequently, the preform 5 is drawn into an optical fiber.

Abstract: In a method of elongating a glass preform comprising the steps of holding both ends of the glass preform 1a with a first holding section 2 and a second holding section 3, respectively; moving the first holding section 2 and the second holding section 3 in a longitudinal direction of the glass preform 1a with the moving speed of the first holding section 2 faster than that of the second holding section 3 and, at the same time, heating and softening the glass preform 1a by a heating section 4 successively; and elongating the glass preform 1a by a tensile force applied thereto, so as to form an elongated body 1c; an electric furnace is employed in the heating section 4; and said method further comprising the steps of setting a reference value R1 with respect to an outside diameter at a specific position 1d in a tapered region 1b in the glass preform 1a in the process of elongating; acquiring an actually measured value R2 at the specific position 1d; and controlling the moving speed of the first holding section 2

Abstract: The invention includes a ferrule having a layer of material on an inner surface of a hole therein which is selected to be preferentially softenable relative to the bulk material of the ferrule. The ferrule according to the present invention can be fused to optical fibers, capillaries and the like while reducing deformation of the fused component and the ferrule.

Abstract: Embodiments of the invention include a method and apparatus for making optical fiber preforms and optical fiber. The method includes the steps of positioning an overclad tube around a preform core rod, heating the overclad tube along the length thereof in the presence of a pressure gradient to collapse onto the preform core to form the overclad optical fiber preform, and adjusting the radial size of a heated portion of the preform core rod and/or the overclad tube to actively match the radial dimensions of the preform core rod along the length thereof with corresponding portions of the overclad tube. The active matching reduces variations in the physical dimensions of the preform core rod and/or the overclad tube, which improves transmission and other performance characteristics of fiber drawn from the created preform, e.g., by maintaining a relatively constant D/d ratio of the preform.

Abstract: Making a polymer-clad optical fiber comprising a step of determining at a plurality of temperatures the delamination resistance of the polymer coating from fiber. The delamination resistance at ambient temperature can be compared with a predetermined target value for delamination resistance in use. The delamination resistance at elevated temperature can be compared with a predetermined lower target value for ease of strippability. Coated optical fiber having delamination resistances outside the predetermined ranges will typically be rejected.

Abstract: An optical fiber and method of making, wherein the optical fiber alternates between regions having different diameters along its length, wherein the refractive index of said blank and the diameters of said fiber are chosen to result in a fiber having alternating regions of positive and negative dispersion at a wavelength which is greater than 1480 nm, yet preferably has a low net dispersion and dispersion slope. A preferred such profile consists of a core region surrounded by a cladding region, said core region comprised of an central core region which is updoped with respect to said cladding region, said central core region surrounded by a moat region which is downdoped with respect to said cladding region, and said moat region is surrounded by an annular ring region which is updoped with respect to said cladding region. In addition, a family of profiles is presented which may be used to produce very low dispersion slope fibers.