The invention relates to microstructured optical fibers that are drawn through hollow channels and have a core region, which extends along a fiber longitudinal axis, and a jacket region surrounding the core region. The aim of the invention is to reduce a damping increase due to corrosion and to reduce the emission of chlorine on the basis of the microstructured optical fibers. This is achieved in that at least some of the hollow channels are delimited by a wall material made of synthetic quartz glass which has a chlorine concentration of less than 300 wt. ppm and oxygen deficiency centers in a concentration of at least 21015 cm-3.

A glass including silica and titania is disclosed. An average hydroxyl concentration of a plurality segments of the glass is in a range from about 20 ppm to about 450 ppm, an average titania concentration of the plurality of segments is in a range from about 6 wt. % to about 12 wt. %, and each segment of the plurality of segments has a length of about 12.7 mm, a width of about 12.7 mm, and a height of about 7.62 mm. The hydroxyl concentration of each segment is measured using a Fourier transform infrared spectroscopy in transmission, the refractive index is measured using an optical interferometer with a 633 nm operating wavelength and a resolution of 270 microns270 microns pixel size, and the average titania concentration is determined based upon the measured refractive index.

The present embodiment relates to an optical fiber preform manufacturing method in which two or more kinds of alkali metal elements are diffused and doped to an inner surface of a glass pipe. The manufacturing method includes: a first drying step performed at a temperature equal to or lower than a lowest temperature among melting point temperatures of the alkali metal salt raw materials; and a second drying step performed at a temperature which is equal to or higher than a highest temperature among the melting point temperatures of the alkali metal salt raw materials and at which vapor pressures of the alkali metal salt raw materials are 2 mmHg or lower.

The present invention relates to a method of manufacturing an optical fiber preform for obtaining an optical fiber with low transmission loss. A core preform included in the optical fiber preform comprises three or more core portions, which are each produced by a rod-in-collapse method, and in which both their alkali metal element concentration and chlorine concentration are independently controlled. In two or more manufacturing steps of the manufacturing steps for each of the three or more core portions, an alkali metal element is added. As a result, the mean alkali metal element concentration in the whole core preform is controlled to 7 atomic ppm or more and 70 atomic ppm or less.

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 discharge lamp includes a discharge vessel. A xenon gas is sealed within the discharge vessel so as to serve as a light emitting gas, the discharge vessel is made from quartz glass, a pair of electrodes are arranged so as to face each other in the discharge vessel, and the discharge vessel has a chip portion. The chip portion is made from a glass member that has a composition different from that of the discharge vessel, and the glass member has a transmittance of 50% or more over a wavelength range from 170 nm to 300 nm.

A discharge lamp includes a discharge vessel. A xenon gas is sealed within the discharge vessel so as to serve as a light emitting gas, the discharge vessel is made from quartz glass, a pair of electrodes are arranged so as to face each other in the discharge vessel, and the discharge vessel has a chip portion. The chip portion is made from a glass member that has a composition different from that of the discharge vessel, and the glass member has a transmittance of 50% or more over a wavelength range from 170 nm to 300 nm.

Provided is a silica glass member which exhibits high optical transparency to vacuum ultraviolet light and has a low thermal expansion coefficient of 4.010.sup.7/K or less at near room temperature, particularly a silica glass member which is suitable as a photomask substrate to be used in a double patterning exposure process using an ArF excimer laser (193 nm) as a light source. The silica glass member is used in a photolithography process using a vacuum ultraviolet light source, in which the fluorine concentration is 1 wt % or more and 5 wt % or less, and the thermal expansion coefficient at from 20 C. to 50 C. is 4.010.sup.7/K or less.

One aspect is a process for the preparation of a quartz glass body including providing a silicon dioxide granulate wherein the provision includes providing silicon dioxide powder, and processing the silicon dioxide powder to obtain a silicon dioxide granulate. The silicon dioxide granulate has a larger particle diameter than the silicon dioxide powder. The processing includes processing the silicon dioxide powder to obtain a silicon dioxide granulate I, wherein the silicon dioxide granulate I has a first carbon content wC(1), treating the silicon dioxide granulate I with a reactant to obtain a silicon dioxide granulate II with a further carbon content wC(2), wherein the further carbon content wC(2) is less than the first carbon content wC(1), making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate I prepared from a pyrogenically produced silicon dioxide powder, treating the silicon dioxide granulate I with a reactant at a temperature in a range from 1000 to 1300 C., and making a glass melt out of the silicon dioxide granulate. A quartz glass body is made out of at least a part of the glass melt. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to a light guide, an illuminant, and a formed body, each of which is obtainable by further processing of the quartz glass body. One aspect additionally relates to a process for the preparation of a silicon dioxide granulate II.