Abstract: In the method of making a preform for a high numerical aperture gradient index optical waveguide, the concentration of two dopant constituents is changed during fabrication. Concentration of the first dopant, GeO.sub.2, is changed radially as the preform is built up in order to produce the desired radial refractive index gradient. The concentration of the second dopant, B.sub.2 O.sub.3, is changed radially to compensate for the radial change in thermal expansion coefficient caused by the varying GeO.sub.2 concentration. B.sub.2 O.sub.3 is added to the cladding layer to make the thermal expansion coefficient of the cladding equal to or greater than the composite thermal expansion coefficient of the core. The magnitude of residual tension at the inner surface caused by thermal expansion gradients is reduced and premature cracking of the preform is eliminated.

Abstract: A substantially continuous method of and apparatus for forming an article suitable for an optical waveguide preform wherein the starting member is continuously removed is disclosed. The preform is formed by providing a starting member or bait and applying the particulate material to the exterior surface of the starting member to form a coating thereon. The coating is longitudinally translated while simultaneously additional particulate material is applied to the coating to form a preform body with the preform body thereafter being longitudinally translated. While longitudinally translating the preform body and applying additional particulate material to the end thereof, the starting member is continuously removed from the preform body leaving a longitudinal aperture remaining in the preform body. The particulate material may be applied by one or more burners, the output of which may be controlled to provide a predetermined desired cross sectional composition variation of the resulting preform body.

Abstract: Disclosed is a range of resistor compositions which exhibit a stability of less than 0.5 percent change in resistance after 2,000 hours at 175.degree. C., and yet which also have a temperature coefficient of resistance less than + or -25 ppm per degree Celsius. These compositions all comprise alloys of nickel, chromium and silicon, within a selected range. Also, disclosed is a method of manufacturing these compositions on a reproducible basis. The method includes the provision of a first silicon target and a second nickel chromium target and the subjecting of these targets to a sputtering gas and electrical potential such that the aforementioned silicon, nickel, chromium alloys are formed.

Abstract: A method of coating an optical waveguide filament employing a die body having an at least partly tapered central aperture and radial means for introducing coating material to the central aperture is disclosed. The method includes exposing the optical waveguide filament to the coating material within the tapered aperture of the die body. The die body and an apparatus for coating the filament is also disclosed.

Abstract: An article suitable as an integral handle for an optical waveguide preform is disclosed. The article comprises a hollow tubular member defining a substantially longitudinal aperture and having one end thereof tapered and of diminishing wall thickness for the length of said taper. Adjacent the tapered end is disposed an outwardly extending protrusion which is embedded in one end of an optical waveguide preform forming an integral unit therewith. Means are provided for a substantially gas-tight connection to the handle so that a gaseous medium may be flowed through the handle and the optical waveguide preform in its porous soot form. Means are also provided for attaching and securing the composite structure to a source of gaseous medium. Also disclosed is the combination of an optical waveguide preform rigidly affixed to a handle.

Abstract: A method of forming a preform suitable for optical waveguides is disclosed. The method comprises providing a hollow tubular member defining a substantially longitudinal aperture and having one end thereof tapered and of diminishing wall thickness for the length of said taper. Adjacent the tapered end is formed an outwardly extending protrusion. A starting mandrel is inserted into the aperture so as to extend therebeyond. Particulate material is deposited over at least a portion of each of the extending part of the hollow tubular member and the starting mandrel whereby the extending protrusion is embedded in one end of the resulting optical waveguide preform. An integral unit including the tubular member and the preform is thus formed. Means are provided for a substantially gas-tight connection to the handle so that a gaseous medium may be flowed through the handle and the optical waveguide preform in its porous soot form.

Abstract: A substantially continuous method for drying, consolidating and drawing an optical waveguide preform is disclosed. A porous soot preform suspended from a substantially hollow longitudinal preform handle having a longitudinal aperture therein is provided. The end of the hollow preform handle is connected to a source of gaseous drying medium, and a quantity of the gaseous drying medium is flowed through the aperture in the porous soot preform and through the porous walls of the preform thereby drying the preform structure. The extending end of the porous soot preform is heated to the consolidation temperature of the materials thereof to progressively consolidate the preform from the extending end thereof. The consolidated end of the preform is further heated to the drawing temperature of the materials thereof and a filament is drawn from the extending end of the consolidated preform.

Abstract: A dielectric material which meets the temperature requirements for X7R grade capacitors consists of a fired ternary niobate composition. A dielectric constant of at least 2000 and a limited change in dielectric constant with temperature is present in compositions having the approximate formula:Pb.sub.x .multidot.Ba.sub.y .multidot.Sr.sub.z (Nb.sub.2 O.sub.6)where x, y and z represent the mole fractions of each of Pb, Ba and Sr which are in the ranges of X=0.1 to 0.4, y=0.1 to 0.4, z=0.4 to 0.5, the sum of x, y and z being 1. Modifications which increase these ranges include doping the ternary niobate composition with a rare earth and substitution of Ta.sub.2 O.sub.5 for Nb.sub.2 O.sub.5. During preparation, the composition is heated in a cycle which produces a mixture of phases, primarily rhombohedral and tetragonal structures similar to those of PbNb.sub.2 O.sub.6.

Abstract: The diameter of an optical fiber being drawn is monitored and controlled by an optical measuring technique. An electrical input signal is generated from the fringe pattern produced by directing a laser beam onto the fiber. The input signal is connected to appropriate terminals of first, second, third and fourth comparators. The input signal is delayed 180.degree. to provide an input signal to the remaining two terminals of the first and second comparators and is delayed 90.degree. to provide an input signal to the remaining terminals of the third and fourth comparators. The output pulses from the comparators are shaped, summed and counted to provide a control signal for the fiber drawing apparatus.

Abstract: This invention pertains to an apparatus for controlling the diameter of a glass bait tube during the deposition of glassy layers therein. The exhaust end of the bait tube is connected to a vented chamber. A gas source is connected to the chamber by a mass flow controller. A moving hot zone is generated within the bait tube while reactant gases flow therethrough in order to form uniform glassy deposits within the bait tube. An outer diameter monitor measures the bait tube diameter within the hot zone and provides an output signal to a controller which compares the output signal to a set point and provides a control signal to the mass flow controller. By varying the flow of gas into the chamber, the pressure within the bait tube is maintained at the level necessary to provide the desired tube diameter.

Abstract: Apparatus and method for assuring the quality of the results obtained from a blood gas analyzer. The apparatus comprises a device for storing blood gas quality control reagent comprising a first variable volume, gas impermeable container for receiving the reagent. The reagent is stored exclusively in the liquid phase therein. A valved exit passageway emanates from the container which container is situated in a second container surrounding the first, a space being present therebetween and a compressed gas situated in the space. Upon opening the valve, the compressed gas decreases the volume of the first container and reagent is expelled through the exit passageway. The present device is uneffected by changes in ambient temperature since the reagent is stored exclusively in the liquid phase. The device is reusable since a portion of the reagent may be expelled without contamination of the remaining contents.

Abstract: In drawing an optical waveguide, the blank is heated by a beam of laser radiation which has substantially zero power from the axis of the blank to a prescribed radial position and substantially uniform power from that position to a greater radial position. A rotating spinner splits radiation from the laser into two rotating beams, the paths of which are made to be non-intersecting with the axis of the blank being drawn. A conical reflector forms the radiation into a circumferential beam through which the blank passes.

Abstract: A method of incorporating an additive or dopant oxide into a glass body produced by the oxidation of vaporous source material in a flame. The resultant glassy particles are deposited to form a porous preform having a uniform refractive index. During the consolidation process, the preform is subjected to an atmosphere including a drying agent which penetrates the interstices of the soot preform to simultaneously dry and dope the preform.

Abstract: A method of making solid glass articles by the flame hydrolysis technique. First and second layers of glass soot produced by a flame hydrolysis are deposited on the outside surface of a mandrel to form a porous preform. The refractive index of the soot particles of the first layer is greater than that of the soot of the second layer, and the soot of the first layer has a viscosity lower than that of the second layer. The mandrel is removed, and the soot preform is subjected to a high temperature whereby it is consolidated to form a dense glass blank. The glass surface tension and the relative viscosities of the inner and outer portions of the preform cause the aperture to close during the consolidation process. The resultant blank may be heated and drawn into a filament, or it may be sliced into optical windows, lenses or the like.CROSS-REFERENCE TO RELATED APPLICATIONThis is a continuation of application Ser. No. 922,559, filed July 7, 1978, which is a continuation-in-part application of U.S.

Abstract: A rapid curing polybutadiene resin system dielectric coating composition suitable for coating electrical components such as thin film resistors is disclosed. This composition cures very rapidly and greatly improves adhesion to the coated article.

Abstract: A control system for a slide centrifuge includes a ratio checking circuit which produces a signal when the ratio between the light passing through the slide and the rate of change of this light passes through a predetermined critical value. When this ratio passes through the critical valve, spinning is stopped. This effectively stops spinning when the rate of reduction of blood cell density on the slide slows, thereby producing better slides for clinical analysis.

Abstract: A method of coating an optical waveguide filament employing a die body having an at least partly tapered central aperture and radial means for introducing coating material to the central aperture is disclosed. The method includes exposing the optical waveguide filament to the coating material within the tapered aperture of the die body. The die body and an apparatus for coating the filament is also disclosed.

Abstract: Coupling among discrete propagation modes of light energy is achieved by providing perturbations of finite length in an optical waveguide. An optimal function characterizing the perturbation is disclosed along with a method of implementing the function to obtain uniform coupling strength over a desired range of modes.

Abstract: A method of forming a preform or blank for an optical filament, the preform itself, and resulting optical filament is disclosed. A hollow cylindrical substrate is provided within which is disposed a burner having a substantially radial flame. Reactants are flowed into the hollow cylindrical substrate in the annular space between the inner surface of said substrate and the exterior of said burner. A hot zone is established within the interior of said substrate in the vicinity of said radial flame so that the reactants are reacted to produce a suspension of particulate material. The burner is traversed substantially along the longitudinal axis of the substrate whereby the hot zone is caused to move along the length of said substrate. A portion of the particulate material formed within the hot zone travels downstream where at least a portion thereof comes to rest on the inner surface of the substrate to subsequently form a continuous glassy deposit thereon.

Abstract: In making a preform for an optical waveguide, the bait rod is coated with carbon. After the preform is built up on the bait rod, it is easily removed. The carbon coating produces a smooth improved inner surface in the preform, thereby eliminating flaws which otherwise may be present when the preform is drawn into a waveguide.