Abstract: Disclosed is an optical fiber that includes a central core that is suitable for transmitting and amplifying an optical signal and an inner optical cladding that is suitable for confining the optical signal transmitted within the central core. The central core is formed from a core matrix that contains silica-based nanoparticles doped with at least one rare earth element. The disclosed optical fiber can be used with limited optical losses even in an environment with strong ionizing radiation.

Abstract: The present invention discloses a process for making rare earth (RE) doped optical fiber by using RE oxide coated silica nanoparticles as the precursor material, more particularly the method of the present invention involves preparation of stable dispersions (sol) of RE oxide coated silica nanoparticles at ambient temperature and applying a thin coating on the inner surface of silica glass tube following dip coating technique or any other conventional methods, of the said silica sol containing suitable dopants selected from Ge, Al, P, etc.

Abstract: The present invention discloses a process for making rare earth (RE) doped optical fibre by using RE oxide coated silica nanoparticles as the precursor materia, more particularly the method of the present invention involves preparation of stable dispersions (sol) of RE oxide coated silica nanoparticles at ambient temperature and applying a thin coating on the inner surface of silica glass tube following dip coating technique or any other conventional methods, of the said silica sol containing suitable dopants selected from Ge, Al, P, etc.

Abstract: Dental glass powders, methods for producing the powders and dental compositions including the glass powders. The powders preferably have a well-controlled particle size, narrow size distribution and a spherical morphology. The method includes forming the particles by a spray pyrolysis technique. The invention also includes dental filler and restorative compositions that include the glass powders.

Abstract: Disclosed are silica structure crack detection methods and apparatuses particularly useful in sol-gel fabrication processes. A wave signature of a crack in the silica structure is sensed to indicate that cracking has occurred. Sensing may be by active or passive techniques and may include contact and non-contact methods of monitoring. Further disclosed is a silica structure fabrication process development method wherein cracks are monitored by sensing a wave signature of a crack to isolate a process step or steps in which cracking has occurred. Process parameters are then adjusted in the isolated step to diminish or eliminate cracking.

Abstract: An optical item comprising an organic or mineral glass substrate (1) and a transparent polymeric material layer (3), characterized in that it comprises at least one intermediate layer (2) in direct contact with one main side of the substrate and the polymeric material layer, the intermediate layer(s) being made of particles of at least one colloidal mineral oxide and optionally of a binder, such (an) intermediate layer(s) having an initial porosity, and the initial porosity of the intermediate layer(s) being filled either by material from the polymeric material layer or by the substrate material if the latter is made in an organic glass and, optionally partly by the binder when present, so that the intermediate layer(s), after initial porosity filling, each represent a quarter waveplate with a wavelength in the range from 400 to 700 nm, preferably from 450 to 650 nm.

Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing deionized water with a monomer and a dimer to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fused silica and a dispersion agent; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the dispersed sol at the ambient temperature to stabilize silica particles, and removing air voids from the sol; and, (e) adding a polymerization initiator and a gelation agent to the aged sol.

Abstract: A silica sol-gel fabrication process is provided which allows improved control of the shrinkage that takes place during the drying of a gel body. In particular, the invention makes it possible to attain extremely low shrinkage through the completion of the drying stage, e.g., below 1% linear shrinkage, in relatively large sol-gel bodies of (dry weight) 1 kg or more, typically 10 kg or more, or even 40 kg or more, compared to the much higher shrinkages typically encountered. Specifically, use of a particular polymeric additive makes it possible for a gel body to experience linear shrinkage at least 55% less than an identical process without the polymeric additive.

Abstract: Disclosed are apparatus and method for ultrasonically dispersing a silica sol such as is used in a process of manufacturing a silica glass by a sol-gel method. The apparatus includes a sol feeder for holding a sol to be dispersed, a sol container for containing the ultrasonically dispersed sol, a medium tank having a liquid-phase ultrasonic medium, an ultrasonic vibrator for generating ultrasonic waves within the tank, and a sol pipe for providing a sol feeding path connecting the sol feeder and the sol container to each other, the sol pipe having a portion submerged under the ultrasonic medium in the medium tank. The portion of the sol pipe submerged under the ultrasonic medium has a shape bent in a zigzagged fashion.