Abstract:
The manufacture of a GRIN lens using a sol-gel process includes forming a wet gel from an alcohol solution containing a silicon alkoxide, a dopant alkoxide, and an aluminum alkoxide, first, an alcohol solution containing the silicon alkoxide and the aluminum alkoxide as is prepared, and then the dopant alkoxide is mixed thereto.
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.
Abstract:
A method for manufacturing a GRIN lens includes the steps of forming a wet gel provided with a concentration distribution having a different concentration of a refractive index distribution imparting metal that differs in concentration in a radial direction, drying the wet gel to form a dry gel having a bulk specific gravity ρ (g/cm3), sintering the dry gel to form a GRIN lens base material and stretching the GRIN lens base material while heating. The method is characterized in that, in the step of sintering the dry gel, partial pressures of oxygen during sintering at 800° C. or higher are 10−1 Pa or lower and also the relation between a rate of temperature increase ν (° C./hr) and a bulk density ρ of the dry gel during sintering at 1,000 to 1,150° C. is defined by ν≦105*EXP (−12ρ). As a result of this, the GRIN lens, which has a large numerical aperture and a small diameter, can stably and easily be manufactured.
Abstract:
The present invention relates to microspheres (i.e., beads) that comprise titania and bismuth oxide. The glass microspheres further comprise zirconia. The invention also relates to retroreflective articles, and in particular pavement markings, comprising such microspheres.
Abstract:
The invention is directed to ultra-low expansion glasses to which adjustments have been made to selected variables in order to improve the properties of the glasses, and particularly to lower the expansivity of the glasses. The glasses are titania-doped silica glasses. The variables being adjusted include an adjustment in β-OH level; an adjustment to the cooling rate of the molten glass material through the setting point; and the addition of selected dopants to impact the CTE behavior.
Abstract:
Highly durable silica glass containing 0.01% to 2% by weight of at least one element selected from magnesium, calcium, strontium, barium, yttrium, hafnium and zirconium. The silica glass is produced by melting a powdery material comprising a finely divided silica powder and a finely divided zirconium-containing substance by oxyhydrogen flame or plasma are to form an accumulated molten material layer, and extending the molten material layer outwardly in radial directions.
Abstract:
The present invention concerns a preform for an optical fiber, an optical fiber so obtained and methods for making the same. The fiber is characterized in that porous glass doped with at least one dopant is used. Resulting fibers can be used to make high attenuation fibers.
Abstract:
Applicants have determined that much of the nonuniformity in solution doped preforms is due to nonuniformity of the soot layer caused by the high temperature necessary for complete reaction, and that MCVD fabrication using reaction temperature lowering gases such as nitrous oxide (N.sub.2 O) can produce more uniform soot layers. The conventional oxygen/reactant gas mixture presents a very small temperature window in which a uniform silica soot layer can be deposited without sintering. If the temperature in oxygen is too low, SiCl.sub.4 will not react completely and silicon oxychlorides will form. This degrades the soot layer and makes it unusable. If the temperature is too high the soot layer begins to sinter, decreasing the surface area and porosity. Adding a reaction temperature lowering gas lowers the reaction temperature and enables deposition of soot on the tube wall at a temperature substantially lower than the sintering temperature. This results in a more uniform, porous soot layer along the length of the preform and from one preform to another; and, in turn, the greater uniformity permits more uniform solution doping.
Abstract:
The present invention includes an optical fiber amplifier having a core and cladding layer. The core includes Zirconium dioxide (ZrO.sub.2) and a rare earth material. The core may be co-deposited with SiO.sub.2. A co-dopant of Ytterbium (Yb) may also be used. The optical fiber amplifier is well suited for use in the 1300 nm band when pumped with an optical source of appropriate power and frequency.
Abstract:
This invention is directed to the production of essentially defect-free high purity fused silica glass articles, the method comprising the following steps: (a) forming a green body from silica particulates or a porous body of amorphous silica; (b) sintering said body in a chamber by raising the temperature of the chamber to above 1720.degree. C., while purging the chamber with helium or applying a vacuum to the chamber; and (c) consolidating the sintered body in a chamber by raising the temperature within the chamber to at least 1750.degree. C., introducing an inert gas into the chamber at a pressure less than about 6.9 MPa (1000 psig), and cooling the chamber while maintaining the pressurized atmosphere to a temperature at least below the annealing point of the glass. In the most preferred practice, a green body of silica particulates will be prepared via a sol-gel process.