International Telephone and Telegraph Corporation

Adolf R Asam

John Treagus Balkwill

Mokhtar S Maklad

A process is disclosed for finishing high-strength multilayer optical preforms capable of being drawn into long optical fibers useful for light-wave communications. The preforms are of the type prepared by sequential chemical-vapor-deposition of the various desired glass layers within a tubular glass substrate that is then collapsed into a solid cylindrical preform comprising a cylindrical light-transmitting core surrounded by a concentric cladding layer and one or more additional layers within the collapsed substrate. In order for the outermost deposited additional layer to constitute a thin high-compression layer on the surface of the completed optical structure, it is necessary first to remove substantially all of the substrate layer from the preform in such a manner as to leave the adjoining high-compression layer intact. This is accomplished by selecting a glass for the substrate layer that is capable of being etched away faster than the high-compression layer, and then using controlled preferential etching to remove the substrate layer without penetrating or damaging the high-compression layer. This method makes it possible to provide a thinner and more effective outer high-compression layer, on the surface of the completed preform, which is of uniform radial thickness regardless of any nonlinearity or non-concentricity of the core, enclosing layers, or substrate layer. An optical fiber drawn from the completed preform will then retain a uniform high-compressive stress in its outer layer that contributes materially to its tensile strength, durability, and fiber life.

Method of fabricating high strength optical preforms

A connector for joining one or more pairs of optical fibers uses a triangular cross-section to precisely align the fibers. One embodiment consists of a glass sleeve which is softened and crimped after inserting the fibers. The sleeve fuses with the fibers and forms a permanent connection.

Multifiber cable splicer

A linear array of electron multiplier microchannels is formed by fusing a plurality of solid core glass fibers into a rectangular array. A number of arrays is then sandwiched between a pair of glass plate support members fused into a linear arrangement followed by treating to form the electron multiplier. Treatment comprises subjecting the arrangement to an acid etch for removing the core material and hydrogen firing to activate the core walls for secondary electron emission. The apparatus finds application as an ion-electron converter in focal plane mass spectrometers where high electron gain is required.

Strip microchannel electron multiplier array support structure

A low loss multilayer optical fiber having good transmission propertiesin the infrared region of the spectrum is produced by depositing the core and cladding materials on the inner surface of a collapsible silica tube in the absence of moisture. A barrier layer is interposed between the silica tube and the cladding to prevent the migration of OH and transition metal ions during the tube collapsing and fiber drawing processes.

Low loss multilayer optical fiber

Method for making strip microchannel electron multiplier array

A method for forming optical fibers reduces losses of germania dopant due to evaporation during chemical vapor deposition. After deposition of a high purity silica layer on the inner surface of a hollow silica tube, the tube is closed at one end and loaded with a small amount of crystalline germanium compound, such as germanium iodide. The other end is then also sealed and the tube is heated to vaporize the GeI.sub.4 and deposit a coating of germanium. This process may be repeated to build up the Ge layer. The tube is then broken open at both ends and the iodine vapor removed. The germanium layer is oxidized and heated to diffuse germania into the silica layer to provide a doped high index of refraction core layer on a lower index cladding layer. The tube and layers are then collapsed to form a preform which is later drawn into the optical fiber.

Growing community of inventors

Daleville, VA, United States of America

Adolf R Asam