Abstract: The production of an optical component from quartz glass, by elongation of a coaxial arrangement of a core rod and a hollow cylinder of a given length, is known. The arrangement is thus introduced into a heating zone with a vertical orientation, such that the lower end begins to partly soften and the component is drawn downwards from the softened part. The hollow cylinder has an inner passage, provided with a restriction in the region of the lower end thereof, on which the core rod is supported. Several methods are disclosed for formation of the restriction in which the inner passage (55) is mechanically machined to a final dimension and, in one version of the method, the restriction in the inner passage (55) is generated by means of softening the lower end face of the hollow cylinder, swaged against a tool and thus folded inwards with formation of a peripheral bead ring.

Abstract: In a known method for producing a quartz glass tube by means of flame hydrolysis of a silicon-containing start component, SiO2-containing particles are produced, said particles are deposited on a carrier, forming a soot tube having a porous soot wall with a predetermined radial soot density profile, and the soot tube is treated in a chlorine-containing atmosphere and is then vitrified.

Abstract: An optical fiber preform includes a core rod and an overclad tube having an open, distal end dimensioned to enter the mouth of a vertical fiber draw furnace. A plug is fixed in the region of the distal end of the tube, and the core rod is disposed axially inside the overclad tube so that a distal end of the rod is restrained from downward movement by the plug as the tube enters and descends into a hot zone of the draw furnace. The distal end of the tube is heated in the furnace hot zone until the tube and the plug soften and fuse with one another. The tube then collapses onto the core rod to produce a drop from which an optical fiber having desired properties may be drawn.

Abstract: A method for measuring trace quantities of OH groups in quartz glass comprises preparing a set of test pieces comprising a reference test piece from a blank of a quartz glass body whose OH group content is known and a sample test piece from a quartz glass body whose OH group content is to be measured, having two planar planes faced to each other, setting the sample test piece and the reference test piece in an infrared spectrophotometer; successively irradiating perpendicular to one of the two planar planes an incident infrared radiation in a wavelength region of approximately 2500 nm to approximately 2950 nm, while simultaneously detecting the outgoing radiation spectrum from the other plane; obtaining the difference of the outgoing radiation spectrum of each of the test pieces; selecting the absorbance peak assigned to OH groups at a wavelength of 2720 nm to obtain the peak height thereof; and calculating the concentration of OH groups from the peak height in the sample test piece.

Abstract: A method for measuring trace quantities of OH groups in quartz glass comprises preparing a set of test pieces comprising a reference test piece from a blank of a quartz glass body whose OH group content is known and a sample test piece from a quartz glass body whose OH group content is to be measured, having two planar planes faced to each other, setting the sample test piece and the reference test piece in an infrared spectrophotometer; successively irradiating perpendicular to one of the two planar planes an incident infrared radiation in a wavelength region of approximately 2500 nm to approximately 2950 nm, while simultaneously detecting the outgoing radiation spectrum from the other plane; obtaining the difference of the outgoing radiation spectrum of each of the test pieces; selecting the absorbance peak assigned to OH groups at a wavelength of 2720 nm to obtain the peak height thereof; and calculating the concentration of OH groups from the peak height in the sample test piece.