Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: A chalcogenide multi-clad optical fiber having a core, a first cladding and one or more subsequent claddings including a chalcogenide glass. The optical fiber may be capable of transmitting visible and inferred light and may be used for a wide variety of semiconductor applications.

Abstract: An optical fiber having microstructured terminal end suitable for reducing Fresnel losses. In an exemplary embodiment, the microstructured surface includes a plurality of protrusions, recesses or combinations thereof that effectively and incrementally change the refractive index of the terminal end of the optical fiber such that the refractive index is gradually drawn closer to the refractive index value of the surrounding environmental medium.

Abstract: Particles including a YAG core and a coating of sintering aid deposited thereon. The particles and agglomerates thereof maybe formed as a powder. The coated YAG-containing particles are well-suited to production of polycrystalline YAG-containing ceramics. The coated YAG-containing particles may be fabricated using a novel fabrication method which avoids the need for formation of a homogeneous powder mixture of YAG and sintering aid. In the method, a solution including a sintering aid or sintering aid precursor is prepared and mixed with YAG-containing particles to form a mixture. The mixture may be sprayed into a drying column and dried to produce coated particles. Alternatively, the YAG particles and sintering aid or sintering aid precursor solution may be separately introduced to the drying column and dried to form coated YAG-containing particles.

Abstract: A ceramic having at least about 90% by weight magnesium aluminate and having a bulk scattering and absorption loss of less than about 1/cm at any wavelength in a range of about 0.23 to about 5.3 microns or 0.2/cm at any wavelength in a range of about 0.27 to about 4.5 microns. A method of making a ceramic by providing a plurality of particles having a magnesium aluminate core and a fluoride salt coating; heating the particles in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C.; and sintering the particles to form a solid ceramic.

Abstract: A ceramic having at least about 90% by weight magnesium aluminate and having a bulk scattering and absorption loss of less than about 1/cm at any wavelength in a range of about 0.23 to about 5.3 microns or 0.2/cm at any wavelength in a range of about 0.27 to about 4.5 microns. A method of making a ceramic by providing a plurality of particles having a magnesium aluminate core and a fluoride salt coating; heating the particles in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C.; and sintering the particles to form a solid ceramic.

Abstract: A photonic band gap fiber and method of making thereof is provided. The fiber is made of a germanate glass comprising at least 30 mol % of a germanium oxide 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 90%. 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: The present invention is generally directed to a device comprising multiple specialty glass optical fibers that combines several different mid-infrared optical signals from multiple optical fibers into one signal in a single optical fiber. In addition, the present invention provides for a method of making the device.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: A method and apparatus for making a substantially void-free microstructured optical fiber using a one-step process is provided. A preform for the optical fiber is prepared, comprising an outer jacket made of solid glass, a cladding having a plurality of microtubes and/or microcanes arranged in a desired pattern within the jacket, and a core which may be solid or hollow, with the cladding and the core extending above the top of the outer jacket. The thus-prepared preform is placed into a fiber draw tower. As the fiber is drawn, negative gas pressure is applied to draw the canes together and consolidate the interfacial voids between the canes while positive gas pressure is applied to the preform to keep the holes of the microcanes open during the fiber drawing. The apparatus includes a jig having support tubes that are connected to a vacuum pump for application of the negative gas pressure and a vent tube connected to a gas supply for application of the positive gas pressure.

Abstract: A thermally stable chalcogenide glass, a process for making the same, and an optical fiber drawn therefrom are provided. A chalcogenide glass having the composition Ge(5?y)As(32?x)Se(59+x)Te(4+y) (0?y?1 and 0?x?2) is substantially free from crystallization when it is heated past the glass transition temperature Tg or drawn into optical fibers. A process for making the thermally stable chalcogenide glass includes purifying the components to remove oxides and scattering centers, batching the components in a preprocessed distillation ampoule, gettering oxygen impurities from the mixture, and heating the components to form a glass melt. An optical fiber formed from the chalcogenide glass is substantially free from crystallization and exhibits low signal loss in the near-infrared region, particularly at wavelengths of about 1.55 ?m.

Abstract: Beam steering apparatus is presented having a Risley double-prism pair with first and second double-prisms disposed along an optical path, where one or more of the prisms are made from a chalcogenide glass material.

Abstract: This invention pertains to a chalcogenide glass of low optical loss that can be on the order of 30 dB/km or lower, and to a process for preparing the chalcogenide glass.

Abstract: A wavelength converter comprising an arsenic sulfide (As—S) chalcogenide glass fiber coupled to an optical parametric oscillator (OPO) crystal and a laser system using an OPO crystal coupled to an As—S fiber are provided. The OPO receives pump laser radiation from a pump laser and emits laser radiation at a wavelength that is longer than the pump laser radiation. The laser radiation that is emitted from the OPO is input into the As—S fiber, which in turn converts the input wavelength from the OPO to a desired wavelength, for example, a wavelength beyond about 4.4 ?m. In an exemplary embodiment, the OPO comprises a periodically poled lithium niobate (PPLN) crystal. The As—S fiber can include any suitable type of optical fiber, such as a conventional core clad fiber, a photonic crystal fiber, or a microstructured fiber.

Abstract: A doped glass composition is provided. A base glass is doped with rare earth ions Terbium Tb3+ and Europium Eu3+ to produce a glass that reduces the transmission of short-wave infrared radiation therethrough without reducing the transmission of visible light. A base glass composition is doped with Tb3+ and Eu3+ ions to an appreciable concentration, in some embodiments in excess of 5 mol % and in other embodiments to a concentration in excess of 1 mol %. A suitable glass for doping according to the present invention includes any glass that can accept rare earth ions at appreciable densities such as the densities described above, and can include oxide-based, fluoride-based, and chalcogenide-based glasses. The doped glass attenuates transmission of short-wave infrared radiation having wavelengths of about 1.8 ?m to about 2.5 ?m and does not reduce transmission of visible light having wavelengths from about 0.4 ?m to about 0.8 ?m.

Abstract: A wavelength converter comprising an arsenic sulfide (As—S) chalcogenide glass fiber coupled to an optical parametric oscillator (OPO) crystal and a laser system using an OPO crystal coupled to an As—S fiber are provided. The OPO receives pump laser radiation from a pump laser and emits laser radiation at a wavelength that is longer than the pump laser radiation. The laser radiation that is emitted from the OPO is input into the As—S fiber, which in turn converts the input wavelength from the OPO to a desired wavelength, for example, a wavelength beyond about 4.4 ?m. In an exemplary embodiment, the OPO comprises a periodically poled lithium niobate (PPLN) crystal. The As—S fiber can include any suitable type of optical fiber, such as a conventional core clad fiber, a photonic crystal fiber, or a microstructured fiber.

Abstract: A photonic band gap fiber and method of making thereof is provided. The fiber is made of a germanate glass comprising at least 30 mol % of a germanium oxide 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 90%. 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: A transparent polycrystalline ceramic having scattering and absorption loss less than 0.2/cm over a region comprising more than 95% of the originally densified shape and further provides a process for fabricating the same by hot pressing. The ceramic can be any suitable ceramic such as yttria (Y2O3) or scandia (Sc2O3) and can have a doping level of from 0 to 20% and a grain size of greater than 30 ?m, although the grains can also be smaller than 30 ?m. In a process for making a transparent polycrystalline ceramic in accordance with the present invention, ceramic nanoparticles can be coated with a sintering aid to minimize direct contact of adjacent ceramic powder particles and then baked at high temperatures to remove impurities from the coated particles. The thus-coated particles can then be densified by hot pressing into the final ceramic product. The invention further provides a transparent polycrystalline ceramic solid-state laser material and a laser using the hot pressed polycrystalline ceramic.

Abstract: A high purity nano-sized Yb3+ doped Y2O3 (Yb:Y2O3) ceramic powder with a narrow size distribution and without hard agglomerates is provided. Also provided is a process for manufacturing the same wherein water in the reaction bath is replaced by a non-water washing agent having little or no hydrogen bonding capability to inhibit the formation of hard agglomerates in the ceramic powder.

Abstract: This invention pertains to a process of bonding a magnesium aluminate spinel article or articles and a germanate glass article or articles including the step of heating them together above the softening temperature of the glass.