Brown University

Other

Physical Sciences, Inc.

Lucent Technologies Inc.

Corning Glass Works

Theodore F Morse

Rajiv Gupta

Avilash Cramer

Paul Waltz

Gary A Moniz

Angus Ian Kingon

Christopher W Bull

Joseph J Helble

John Burnette MacChesney

Edward A Johnson

Arnd Hermann Kilian

Alexis Mendez

Chistopher Bull

A method and apparatus to manufacture a coherent bundle of scintillating fibers is disclosed. A method includes providing a collimated bundle having a glass preform with capillaries therethrough known in the industry as a glass capillary array, and infusing the glass capillary array with a scintillating polymer or a polymer matrix containing scintillating nanoparticles.

Method and apparatus for creating coherent bundle of scintillating fibers

A method and apparatus to manufacture a coherent bundle of scintillating fibers is disclosed. In the method and apparatus, a polymer matrix of a transparent polymer and nanoparticle scintillators is placed on top of a collimated bundle having a plurality of capillaries and pressed in a pressure vessel until the polymer matrix is forced into the capillaries. Pressure is applied via an anvil on top of the polymer matrix. To prevent fracturing of the collimated bundle during pressing, back pressure is supplied to the pressure vessel via a valve, which controls a supply of high pressure gas. Alternatively, the back pressure may also be supplied by a press (and or pressure) and support to the collimated bundle is provided by a high melting point thermoplastic. Heat may be applied to the polymer matrix via the anvil to speed the pressing operation due to the viscosity of the polymer.

A method is disclosed for fabricating a preform suitable for use in manufacturing a wide bandwidth multi-mode optical fiber. The method includes steps of employing a liquid phase spray pyrolysis technique for generating silica soot at a high rate, in combination with a non-chlorine containing liquid silica precursor and a refractory, index of refraction raising additive that overcomes the problems inherent in the use of germanium-based chemistry at typical sintering temperatures. The refractory, index of refraction raising additive is preferably comprised of a Group VB element oxide, such as a tantalum oxide. The liquid precursor is preferably comprised of a polymethylsiloxane, such as hexamethyl di-siloxane, octamethylcyclotetrasiloxane (OMCCTS), or tetramethylcyclotetrasiloxane. The step of employing a liquid phase spray pyrolysis technique includes the steps of: (a) merging at least two liquid streams, one comprised of the liquid silica precursor and another one comprised of the liquid silica precursor in combination with the additive; (b) atomizing, spraying and then combusting the merged streams to form a flame that generates silica soot that contains the additive; and (c) varying the flow rate of at least one of the streams in order to vary a concentration of the additive in the silica soot.

Liquid spray pyrolysis method for the fabrication of optical fiber preforms, with reactant mixing

A fiber optic reflectometer employs an optical fiber near a target substrate in a deposition chamber. The optical fiber is positioned within the chamber so that deposition of a thin film on the substrate also occurs on a portion of the optical fiber. A combination of monochromatic and broadband white light is transmitted through the optical fiber to the film deposited on it, and light reflectance measurements are made to determine, in situ and substantially in real time, such characteristics of the film as its growth rate, thickness, composition, surface roughness and refractive index. Such measurements can be made without bulk optics and without the precise alignment requirements of ellipsometry techniques and apparatus.

Fiber optic reflectance apparatus for in situ characterization of thin films

An optical fiber structure includes: an optical fiber comprising a rare earth doped core (that may be single mode or multi-mode), or several single mode cores, surrounded by a silica material; a glass cylinder tube containing the optical fiber along a length thereof such that the doped core is located at a center of the glass cylinder for a single core, or arranged geometrically around the center for multiple cores; and a support structure disposed between the light guiding section of the optical fiber optical fiber and an inner wall of the tube that functions as a portion of the support structure of the light guiding portion of the optical fiber. The support structure is arranged such that the effective cladding of the core is a gas contained between the optical fiber and the inner wall of the tube for providing the optical fiber with a numerical aperture that is approximately one. A polarization maintaining embodiment is described, as are methods for fabricating the optical fiber structures. To reduce the overall length of the fiber, a chirped Bragg grating may be written into a multi-mode section of the fiber. The optical fiber structures can be used as gain elements in optical fiber lasers, such as those having applications in communications, medical, and manufacturing environments.

Ultra high numerical aperture high power optical fiber laser

The present invention is directed to methods and apparatus for detecting species in a laser cavity. According to one preferred embodiment, a device according to the invention includes: a source of excitation energy at a first wavelength; a first optic fiber; a resonant cavity; an absorption element; and a detector element. The first optic fiber has at least a first portion which is lasant-doped, and is optically coupled to the excitation source. The doping causes the first optic fiber to amplify light. Thus, in response to light coupled from the excitation source, the first optic fiber is capable of lasing. The resonant cavity surrounds the first portion of the optic fiber and has at least a first wavelength-specific reflector, such that laser light at only a second wavelength is amplified in the cavity. The absorption element can expose a sample to the light contained within the resonant cavity. The detector is optically coupled to the resonant cavity. It detects variations in the intensity of the laser light within the resonant cavity. By detecting variations in the intensity of the light in the cavity, the detector can indicate the presence of particular species.

Fiber laser intra-cavity spectroscope

A new method for the manufacture of glass films on substrates involves the flame reaction of an aerosol comprised of droplets of a solution containing all the precursors for the glass. A solution containing the precursors for all oxide components is atomized, and the resulting droplets are reacted in a flame to form spherical glass particles which are deposited on a heated substrate. By moving the substrate through the flame, a homogeneous deposit is achieved. Subsequent heat treatment in a furnace sinters the porous particle layer into a clear glass. The method has been successfully employed for the formation of sodium borosilicate glass films on silicon substrates and rare earth-doped multicomponent glass films for active devices.

Aerosol process for the manufacture of planar waveguides

An apparatus provides high temperature and short residence time conditions for the production of nanoscale ceramic powders. The apparatus includes a confinement structure having a multiple inclined surfaces for confining flame located between the surfaces so as to define a flame zone. A burner system employs one or more burners to provide flame to the flame zone. Each burner is located in the flame zone in close proximity to at least one of the inclined surfaces. A delivery system disposed adjacent the flame zone delivers an aerosol, comprising an organic or carbonaceous carrier material and a ceramic precursor, to the flame zone to expose the aerosol to a temperature sufficient to induce combustion of the carrier material and vaporization and nucleation, or diffusion and oxidation, of the ceramic precursor to form pure, crystalline, narrow size distribution, nanophase ceramic particles.

Apparatus for producing nanoscale ceramic powders

A method and apparatus for sensing electric and electromagnetic fields incorporating a fiber-optic transducer which mounts directly on a conventional optical fiber waveguide. The transducer employs a conductive Fabry-Perot microcavity bounded by a conductive, thin and corrugated diaphragm. When the conductive microcavity is placed in an electric field, the electric field is excluded from within the equipotential microcavity and a net electrostatic force acts on the diaphragm. Likewise, when the conductive microcavity is exposed to an electromagnetic wave, the wave exerts a radiation pressure on the diaphragm. In both cases, the diaphragm deflects linearly and uniformly under the influence of the extremely low electrostatic pressures which are induced. The diaphragm deflection modulates the reflectance within the optical fiber by varying the gap of the cavity. The change in reflected light is measured and correlated to the field strength using an improved dual-wavelength referencing technique which compensates for bending and transmission losses in the optical fiber.

Electric and electromagnetic field sensing system including an optical

Various CVD processes are known whereby glass particles are flowed toward or over a substrate on which they are to be deposited. Because the substrate is cooler than the stream in which the particles are flowing, the thermophoretic force directs the particles toward the substrate. In accordance with the invention a beam of laser light is propagated over the surface in the vicinity of the stream of particles. The particles and/or a component within the stream absorbs the laser energy to induce within the stream of particles a temperature gradient whereby temperature increases with increased distance from the substrate surface.

Method of making optical fiber preform

The invention is an improved form of an ultracentrifuge used in the separation of gases, particularly those of high molecular weight. Through the introduction of an inner cylinder within the outer cylinder of a high speed centrifuge, a higher over-all flow profile efficiency is created. In addition, although a gain of lesser significance, the vacuum core present in ultra centrifuges, which does not contribute to the separative power of the centrifuge, is virtually eliminated. Moreover, for those gases in which the maximum pressure in the centrifuge is limited by a phase change, i.e. the maximum pressure in the centrifuge must be kept below the vapor pressure, the addition of the inner cylinder raises the pressure in the central core region by several orders of magnitude, which permits the subsequent reduction of pressure on the outer walls of both inner and outer cylinders without any portion of the centrifuge being in the Knudsen regime. With this reduction of pressure on the outer walls, the gas can then be centrifuged at a lower temperature, thus further increasing the productive capacity of such a device.

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Providence, RI, United States of America

Theodore F Morse