Abstract:
Method of outside plasma deposition onto a rod (17,22) of silica substantially free from hydroxyl ions, possibly doped to change its refractive index, by reaction with oxygen of a silicon compound and possibly of doping compounds, in the presence of a gas plasma raised to a very high temperature (16) by induction with the help of a high frequency generator (15). The rod on which the silica deposit is made is kept in a sealed chamber (19) separated from the surrounding atmosphere and supplied by a pipe (20) with atmospheric air that is successively passed through a filter (31), a compressor (32) a cooling means (33), a condensation water drain (35) and a final desiccation by adsorption (36, 38). A device for implementing the method is also claimed.
Abstract:
Disclosed is a method of making a polarization retaining single-mode optical fiber. There is initially formed a draw blank having diametrically opposed longitudinal apertures in the cladding glass parallel to the core glass region. The draw blank is drawn into a fiber under such conditions that the apertures close as the fiber is being drawn. The flow of surrounding glass, including the core glass region, toward the collapsing apertures, causes the core to assume an elliptical shape. The apertures are of such cross-sectional area and spacing from the core that the core develops the desired aspect ratio.
Abstract:
The method of enhancing purity of a fused quartz body having opposed boundary surfaces, includes the steps of maintaining the body at a temperature above 1000.degree. C. and at the same time applying a polarizing potential across the boundary surfaces by electrodes in contact with the boundary surfaces so that at least some of the residual impurity ions in it are made to migrate away from one of the boundary surfaces towards the opposite one of the boundary surfaces thereof and are subsequently discharged at the opposite boundary surface. To avoid surface contamination or deformation each of the electrodes is a gaseous electrode of an at least partially ionized helium, argon, neon, krypton, xenon, nitrogen or hydrogen gas or a flame produced by combustion of hydrogen, methane, propane, butane or acetylene. The temperature during the maintaining step is advantageously from 1500.degree. C. to 2100.degree. C., the polarizing potential applied across the boundary surfaces advantageously exceeds 10 volts per mm body thickness and the duration of the maintaining at these temperatures is at least 10 seconds per mm thickness.
Abstract:
A vaccine against a DNA virus, for exmaple, Herpes simplex virus, is prepared by incubating a cell sample which has been infected with the virus, releasing the nuclei in the infected cell material from the cytoplasmic fraction of that material, chemically fixing the polypeptide chains in the cytoplasmic fraction, and forming a precipitate which includes the virus antigens in the cytoplasmic fraction, the precipitate providing the active constituent of the vaccine. A characteristic strain of the virus is preferred, and transfers its characteristics to the vaccine so that vaccinated subjects may subsequently be distinguished from infected subjects.
Abstract:
A rod of silica 14 is inserted into a substrate tube 10 whose bore is lined with a layer 11 of material having a refractive index less than that of silica. This layer 11 is itself covered with a layer 12 of silica. The assembly of the rod and tube is drawn into fibre, or its components are fused together to form a solid cross-section optical fibre preform.
Abstract:
A quartz glass envelope tube for the preparation of a light guide fiber blank, the tube being in the form of a laminate in which the inner layer consists essentially of quartz glass made from rock crystal and the outer layer of synthetic quartz glass. Good mechanical properties, especially tensile strength, are thereby achieved.
Abstract:
A method of making a glass optical fiber having a core surrounded by cladding containing diametrically opposed regions of different TCE than the cladding. Three manufacturing techniques are disclosed. (1) A first glass rod having core and cladding glass is placed centrally in a glass tube. Rods of glass having a TCE different from that of the cladding glass are put on opposite sides of the first rod. Rods of cladding glass are placed in the interstices. (2) A soot preform is deposited on a rotating mandrel. In one embodiment, mandrel rotation is halted to deposit one longitudinally extending region and then rotated 180.degree. to deposit the other such region. In a modified embodiment the mandrel continuously rotates and the deposition burner is continuously supplied with reactant gas for forming a base glass and is also provided with pulses of a reactant gas for modifying the base glass to form the diametrically opposed regions. (3) A CVD process is modified by inserting a pair of tubes into the substrate tube when the longitudinally extending regions are to be deposited. There is passed between the first tube and the pair of tubes a gas which reacts to form particles of a base glass and there is passed through the pair of tubes another gas which reacts to form dopant glass particles which combine with base glass particles to form longitudinal strips of doped base glass within the tube.
Abstract:
This invention is directed to the production of fused silica-containing glass articles of large cross section or diameter wherein at least a surface layer thereof exhibits very high optical quality. The method involves depositing via flame hydrolysis/oxidation reaction a layer of fused silica-containing soot onto a supporting bait, essentially immediately thereafter applying a source of heat concentrated uniformly across the breadth of the soot deposit, but focused only over a relatively small area thereof, to raise the temperature within that area sufficiently to uniformly consolidate the soot in that area into a non-porous glass, and then cooling the glass to room temperature.
Abstract:
A single mode optical waveguide is fabricated in a manner such that the core thereof is subjected to a stress-induced birefringence. A hollow intermediate product is formed by depositing layers of cladding and core glass on the inner surface of a substrate tube. Opposite sides of the intermediate product are heated to cause it to collapse into a solid preform foreproduct having an oblong cross-section. A layer of flame hydrolysis-produced soot having a circular outer surface is deposited on the preform foreproduct and is consolidated to form a dense glass cladding layer thereon. The TCE of the outer cladding layer is different from that of the preform foreproduct on which it is deposited so that when the resultant preform is drawn into a fiber, a stress-induced birefringence exists in the core.
Abstract:
A semiproduct for use in the manufacture of light conducting fibers comprising a core of synthetic quartz glass having a thickness of 6 to 400 mm, the quartz glass containing less than 10 ppm hydroxyl ions and having, in the near infrared spectral range, an optical loss totaling less than 4 dB/km, measured in the mass, the core being fused with a jacket having a wall thickness of 2 to 20 mm and consisting essentially of synthetic quartz glass containing more than 4,000 ppm of fluorine, the jacket having a length of at least 200 mm; a method of producing the same and light conducting fibers derived therefrom.