A method for producing rod lenses with an enveloping diameter of the rod lens face of up to 200 mm and an edge length of at least 800 mm. The method is characterized in that fabrication is performed from a cylindrical rod lens element made from synthetic quartz glass material configured as a fused silica ingot. This is performed using a flame hydrolysis method with a direct one stage deposition process of SIO.sub.x particles from a flame stream onto die that rotates and is moveable in a linear manner with respect to the flame stream.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50° C., preferably 50° C.<T.sub.h<250° C.

Glass-based articles that include a hydrogen-containing layer extending from the surface of the article to a depth of layer. The hydrogen-containing layer includes a hydrogen concentration that decreases from a maximum hydrogen concentration to the depth of layer. The glass-based articles exhibit a high Vickers indentation cracking threshold. Glass compositions that are selected to promote the formation of the hydrogen-containing layer and methods of forming the glass-based article are also provided.

Glass-based articles that include a hydrogen-containing layer extending from the surface of the article to a depth of layer. The hydrogen-containing layer includes a hydrogen concentration that decreases from a maximum hydrogen concentration to the depth of layer. The glass-based articles exhibit a high Vickers indentation cracking threshold. Glass compositions that are selected to promote the formation of the hydrogen-containing layer and methods of forming the glass-based article are also provided.

Glass-based articles that include a hydrogen-containing layer extending from the surface of the article to a depth of layer. The hydrogen-containing layer includes a hydrogen concentration that decreases from a maximum hydrogen concentration to the depth of layer. The glass-based articles exhibit a high Vickers indentation cracking threshold. Glass compositions that are selected to promote the formation of the hydrogen-containing layer and methods of forming the glass-based article are also provided.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein Th is at least about 50° C., preferably 50° C.<Th.sub.h<250° C.

Glass-based articles that include a hydrogen-containing layer extending from the surface of the article to a depth of layer. The hydrogen-containing layer includes a hydrogen concentration that decreases from a maximum hydrogen concentration to the depth of layer. The glass-based articles exhibit a high Vickers indentation cracking threshold. Glass compositions that are selected to promote the formation of the hydrogen-containing layer and methods of forming the glass-based article are also provided.

The invention relates to an optical fiber having an axial direction and a cross section perpendicular to said axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and comprises a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature comprising a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

A diffuser material of synthetically produced, pore-containing quartz glass and a method for the manufacture of a molded body consisting fully or in part thereof. The diffuser material has a chemical purity of at least 99.9% SiO.sub.2, a cristobalite content of not more than 1%, and a density in the range of 2.0 to 2.18 g/cm.sup.3. Starting therefrom, to indicate a diffuser material which is improved with respect to diffuse reflectivity with Lambertian behavior over a wide wavelength range, high material homogeneity and UV radiation resistance, the quartz glass has a hydroxyl group content in the range of at least 200 wt. ppm and at least 80% of the pores have a maximum pore dimension of less than 20 μm.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50° C., preferably 50° C.<T.sub.h<250° C.