An optical fiber for efficient coupling of optical signals to photonic devices. The optical fiber includes a Cl doped tapered core region with a changing outer diameter and changing maximum core refractive index to provide improved coupling at wavelength of interest to photonic devices. The photonic devices may be, for example, silicon photonic devices with an operating wavelength at or near 1310 nm, or at or near 1550 nm.

A method for forming high purity silica articles. The high purity silica articles can be particularly suitable for forming packaging such as packaging for pharmaceutical applications. The method for forming high purity silica articles can comprise, in one embodiment, (a) forming a fused quartz melt from a SiO.sub.2 raw material; (b) forming a quartz tube from the fused quartz melt; (c) treating the quartz tube with an acid composition; (d) heat treating the quartz tube subsequent to treating with the acid composition; and (e) optionally treating the quartz article with an acid composition subsequent to the heat treating operation. The method can enhance the purity of silica glass articles and products made therefrom.

A method for forming high purity silica articles. The high purity silica articles can be particularly suitable for forming packaging such as packaging for pharmaceutical applications. The method for forming high purity silica articles can comprise, in one embodiment, (a) forming a fused quartz melt from a SiO.sub.2 raw material; (b) forming a quartz tube from the fused quartz melt; (c) treating the quartz tube with an acid composition; (d) heat treating the quartz tube subsequent to treating with the acid composition; and (e) optionally treating the quartz article with an acid composition subsequent to the heat treating operation. The method can enhance the purity of silica glass articles and products made therefrom.

Glass ceramics having SiO.sub.2 as main crystal phase and precursors thereof are described which are characterized by very good mechanical and optical properties and in particular can be used as restoration material in dentistry.

Glass ceramics having SiO.sub.2 as main crystal phase and precursors thereof are described which are characterized by very good mechanical and optical properties and in particular can be used as restoration material in dentistry.

Provides is low scattering silica glass suitable as a material of an optical communication fiber. Silica glass has a fictive temperature of at least 1,000 C. and a void radius of at most 0.240 nm, as measured by positron annihilation lifetime spectroscopy. A method for heat-treating silica glass is also provided, which comprises holding silica glass to be heat-treated in an atmosphere at a temperature of at least 1,200 C. and at most 2,000 C. under a pressure of at least 30 MPa, and cooling the silica glass at an average temperature-decreasing rate of at least 40 C./min during cooling within a temperature range of from 1,200 C. to 900 C. A method for heat-treating silica glass also comprises holding silica glass to be heat-treated in an atmosphere at a temperature of at least 1,200 C. and at most 2,000 C. under a pressure of at least 140 MPa, and cooling the silica glass in an atmosphere under a pressure of at least 140 MPa during cooling within a temperature range of from 1,200 C. to 900 C.

A synthetic quartz glass substrate having a controlled hydrogen molecule concentration is prepared by (a) hot shaping a synthetic quartz glass ingot into a glass block, (b) slicing the glass block into a glass plate, (c) annealing the glass plate at 500-1,250 C. for 15-60 hours, (d) hydrogen doping treatment of the glass plate in a hydrogen gas atmosphere at 300-450 C. for 20-40 hours, and (e) dehydrogenation treatment of the glass plate at 200-400 C. for 5-10 hours.

A solid state method of producing inorganic nanoparticles using glass is disclosed. The nanoparticles may not be formed until the glass is reacted with or degraded by contact with a fluid in vivo or in vitro.

A solid state method of producing inorganic nanoparticles using glass is disclosed. The nanoparticles may not be formed until the glass is reacted with or degraded by contact with a fluid in vivo or in vitro.

A method for producing rare earth metal-doped quartz glass includes the steps of (a) providing a blank of the rare earth metal-doped quartz glass, and (b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis. Some rare earth metals, however, show a discoloration of the quartz glass, which hints at an unforeseeable and undesired change in the chemical composition or possibly at an inhomogeneous distribution of the dopants. To avoid this drawback and to provide a modified method which ensures the production of rare earth metal-doped quartz glass with reproducible properties, during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or a neutral plasma.