Abstract: A method and apparatus for making a substantially void-free preform for a microstructured optical fiber using a one-step process is provided. A preform is prepared from specialty glasses using a direct extrusion method. A die for use with the direct extrusion method is also provided, and a method for drawing the preform into a HC-PBG fiber for use in transmitting infra-red wavelength light is also provided. The preform comprises an outer jacket made of solid glass, a cladding having a plurality of air holes arranged in a desired pattern within the jacket, and a core which is hollow.

Abstract: A method and apparatus for making a substantially void-free preform for a microstructured optical fiber using a one-step process is provided. A preform is prepared from specialty glasses using a direct extrusion method. A die for use with the direct extrusion method is also provided, and a method for drawing the preform into a HC-PBG fiber for use in transmitting infra-red wavelength light is also provided. The preform comprises an outer jacket made of solid glass, a cladding having a plurality of air holes arranged in a desired pattern within the jacket, and a core which is hollow.

Abstract: A photonic band gap fiber and method of making thereof is provided. The fiber is made of a non-silica-based glass and has a longitudinal central opening, a microstructured region having a plurality of longitudinal surrounding openings, and a jacket. The air fill fraction of the microstructured region is at least about 40%. The fiber may be made by drawing a preform into a fiber, while applying gas pressure to the microstructured region. The air fill fraction of the microstructured region is changed during the drawing.

Abstract: This invention pertains to a hollow core photonic band gap chalcogenide optical glass fiber and to a fabrication method for making the fiber. The fiber, which is 80-1000 microns in outside diameter, is characterized by a solid glass circumferential region and a structured region disposed centrally within the solid region, the structured region includes a hollow core of 1 micron to several hundreds of microns in diameter surrounded by a plurality of parallel hollow capillaries extending parallel to the core, the core being centrally and longitudinally located within the fiber. Ratio of open space to glass in the structured region is 30-99%. The fabrication method includes the steps of providing a mold, placing chalcogenide micro-tubes around the mold, stacking chalcogenide micro-canes around the stacked micro-tubes, fusing the micro-tubes and the micro-canes to form a preform, removing the mold and drawing the preform to obtain the fiber.

Abstract: An apparatus and method for drawing low loss fluoride glass fibers from a preform. A stream of reactive gas is passed around the preform and fiber so as to prevent moisture and oxygen contamination of the fiber while the fiber is being drawn. The apparatus includes an insulating vessel which surrounds a heating chamber in which the fiber is drawn, and a very narrow heating zone within the chamber for preventing crystallization of the drawn fiber.

Abstract: Chalcogenide glass fibers are coated with metals. The products have impro bending strength and resistance to UV, visible light, and moisture. The metal coating may be applied by any method, such as dip coating or sputtering. Typical metals include In, Sn, Bi, Pb, Tl, Zn, Cd and C.

Abstract: A fiber optic sensor for detecting at least one chemical by evanescent wave spectroscopy comprises a generator of a light signal, a mirror for introducing the light signal into a fiber, a clad optical chalcogenide glass fiber, a mirror for directing the light signal from the fiber into a detector, and a detector for detecting chemicals by the fiber. The fiber comprises a core and a clad having lower refractive index than the core enveloping and being in continuous contact with the core, at least one region on the fiber completely or partially devoid of the clad, and a polymer disposed in the region having affinity for the chemical(s). There being a different polymer in each region if there is more than one region.

Abstract: Glass free of surface carbon deposits, such as carbon film and/or carbon occlusions, and a process for removing such carbon deposits from glass. The process is characterized by the application of a plasma to glass to remove the carbon deposits. The plasma used for this purpose contains active specie which reacts with the carbon deposits to form gaseous carbon products.

Abstract: This invention pertains to optical waveguides which includes waveguides of ll shapes and sizes, preforms, and optical fibers made from the preforms, and to a method for making waveguides devoid of a physical interface.

Abstract: In order to provide a high power heat source having a very clean and invariable heat flux, a ring plasma is induced in a heating zone of a plasma torch including a plurality of coaxial tubular elements and the optical fiber is drawn through a channel passing axially through the center of the plasma torch and of the ring-shaped plasma. In this manner the preform from which the fiber is drawn can be placed in close proximity to the induced plasma without exposure to non-symmetrical temperature variations. Cooling gas passes through the heating zone either in an annular stream surrounding the plasma or in an annular stream passing through the center of the plasma around the preform and the fiber being drawn, or both. The heating zone is protected from environmental disturbances by an extension of the outer tubular element of the plasma torch which surrounds the heating zone.

Abstract: Hydroxyl free deposition with high efficiency and at a high deposition rate may be achieved, even with use of relatively inexpensive raw materials, by utilizing a ring-shaped plasma activated axial chemical vapor deposition obtaining 100% chemical conversion and fractional volatilization of impurities. The plasma is induced in an annular stream of a plasma-forming gaseous medium, and the reactant or reactants used in the axial chemical vapor deposition are introduced into the center of the ring-shaped plasma to be converted by the heat of the plasma flame into soot which is deposited on a bait. An annular stream of a cooling medium flows outwardly past the plasma flame and is circumferentially centered by an extension of the outer tubular element of a plasma torch in which the plasma is generated. An RF generator which induces the plasma is operated at a frequency exceeding 20 MHz to give the plasma flame the desired ring-sloped configuration.

Abstract: An optical fiber or similar article is coated by directing the fiber through a spherical mixing vessel. Two silicone RTV components are directed by means of an annular feed mechanism into the mixing vessel at predetermined flow rates. The motion of the fiber directed through the vessel produces a churning or agitation of the silicone components to uniformly and homogeneously coat the fiber with the mixed components and provide a protective elastomeric coating about the fiber.