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:
The present invention relates to microspheres (i.e., beads) having a high index of refraction. The invention also relates to retroreflective articles, and in particular pavement markings, comprising such microspheres.
Abstract:
High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.
Abstract:
The present invention is generally directed to a photonic bad gap fiber and/or fiber preform with a central structured region comprising a first non-silica based glass and a jacket comprising a second non-silica based glass surrounding the central structured region, where the Littleton softening temperature of the second glass is at least one but no more than ten degrees Celsius lower than the Littleton softening temperature of the first glass, or where the base ten logarithm of the glass viscosity in poise of the second glass is at least 0.01 but no more than 2 lower than the base ten logarithm of the glass viscosity in poise of the first glass at a fiber draw temperature. Also disclosed is a method of making a photonic bad gap fiber and/or fiber preform.
Abstract:
The present invention is generally directed to a photonic bad gap fiber and/or fiber preform with a central structured region comprising a first non-silica based glass and a jacket comprising a second non-silica based glass surrounding the central structured region, where the Littleton softening temperature of the second glass is at least one but no more than ten degrees Celsius lower than the Littleton softening temperature of the first glass, or where the base ten logarithm of the glass viscosity in poise of the second glass is at least 0.01 but no more than 2 lower than the base ten logarithm of the glass viscosity in poise of the first glass at a fiber draw temperature. Also disclosed is a method of making a photonic bad gap fiber and/or fiber preform
Abstract:
A vacuum melting furnace for infrared glass, includes an upper furnace body and a lower furnace body that can be connected with each other or isolated from each other. Vacuum melting of the infrared glass is achieved in the upper furnace body wherein the influence of water in the environment is eliminated. The vacuum negative pressure environments can promote separation of hydroxyl in the structure, which achieves removing of hydroxyl in the glass, and then discharging of the molten infrared glass is conducted at atmospheric pressure in the lower furnace body. By using the vacuum melting furnace for infrared glass, infrared glass with good spectrum transmission performance can be obtained with improved property stability and optical homogeneity, which facilitates the preparation and molding of large sized and special-shaped infrared glass products.
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:
An optical fiber, which has a zero-material dispersion wavelength equal to or greater than 2 μm, and a high nonlinear susceptibility χ3 equal to or greater than 1×10−12 esu, and uses tellurite glass having sufficient thermal stability for processing into a low loss fiber, employs a PCF structure or HF structure having strong confinement into a core region. This enables light to propagate at a low loss. The size and geometry of air holes formed in the core region, and the spacing between adjacent air holes make it possible to control the zero dispersion wavelength within an optical telecommunication window (1.2-1.7 μm), and to achieve large nonlinearity with a nonlinear coefficient γ equal to or greater than 500 W−1 km−1.
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. The interfaces between the support tube and the outer jacket and between the vent tube and the cladding are sealed to ensure that the appropriate application of negative or positive pressure during the draw step is obtained. The preforms according to the present invention can include one or more components fabricated from specialty non-silica glass.
Abstract:
The present disclosure relates to microspheres (i.e., beads) having a high index of refraction. The disclosure also relates to retroreflective articles, and in particular pavement markings, comprising such microspheres.