Abstract: A method of fabricating a photonic crystal or photonic band gap optical fiber comprises providing a preform that includes a plurality of holes in an outer diameter, wherein the holes extend from a first end of a preform to a second end of the preform, and forming at least one radially inwardly-extending slot within the preform such that the slot intersects at least some of the holes, wherein the slot does not intersect at least one hole. The method also includes establishing a first pressure in the holes intersected by the slot by introducing the first pressure to the slot, and establishing a second pressure in the at least one hole not intersected by the slot by introducing the second pressure to an end of the at least one hole not intersected by the slot. The method further includes drawing the preform into a fiber while independently controlling the first and second pressures.

Abstract: Disclosed are process and apparatus for making high purity fused silica glass materials. The process involves depositing soot particles onto an essentially planar deposition supporting surface and modulation of motion of the soot-generating device relative to the deposition supporting surface to result in a low local soot density variation. The apparatus is designed to implement the planar deposition process. The invention makes it possible to produce fused silica glass without the use of potentially contaminating refractory bricks.

Abstract: A method of fabricating an optical waveguide fiber that includes the steps of providing a cylindrical glass optical fiber preform having a longitudinally extending centerline hole, and closing the hole under conditions suitable to result in uniform and symmetric hole closure. The method may include first plugging a first end and a second end of the centerline hole to prevent gas flow therethrough. The method preferably involves closing the centerline hole of the preform by drawing the preform down into an optical waveguide fiber.

Abstract: A method and apparatus for forming a hermetic seal between two substrates includes providing an electromagnetic absorbent sealing material perimetrically about a surface of one of the substrates. Furthermore, the illustrative method includes heating the sealing material. In addition, a package having a hermetic seal and apparati for disposing a sealing material are described.

Abstract: An apparatus for making a crystal pre-melt includes a hermetically-sealed muffle furnace made of a non-porous refractory material, at least one port for entry and exit of gaseous substance within the muffle furnace, a temperature-controlled zone defined inside the muffle furnace, and a crucible for holding crystal raw material in solid or molten form inside the muffle furnace. The crystal pre-melt is made by disposing crystal raw material in loose powder, pressed powder, granular, or densified form in the temperature-controlled zone, heating the temperature-controlled zone to a treatment temperature that enables reaction between a fluorinating agent and oxides in the crystal raw material, reacting the fluorinating agent with the crystal raw material to produce volatile gases, removing the volatile gases from the muffle furnace, heating the crystal raw material to form a melt, and solidifying the melt to form the crystal pre-melt.

Abstract: The invention includes methods and apparatus for depositing soot onto a glass surface to minimize water in the deposited soot and the diffusion of the water into the glass surface. The invention includes depositing a first layer of soot a on the glass surface at a first forward traverse rate and depositing a second layer of soot at a second forward traverse rate.

Abstract: A method of making crystals includes suspending a porous preform made of a crystal raw material in a hermetically-sealed chamber, heating the porous preform to a selected treatment temperature that enables reaction between a fluorinating agent and oxide impurities in the porous preform and reacting the fluorinating agent with the oxide impurities at the selected treatment temperature for a selected time period, filling a crucible in the hermetically-sealed chamber with a melt formed from at least a portion of the porous preform, and progressively moving the melt through a temperature gradient zone defined inside the hermetically-sealed chamber.