Abstract: 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.

Abstract: A method and means is disclosed for continuously monitoring an optical fiber's attenuation or loss as it is being formed, which includes: a light source, which may be the heated fiber itself during drawing operations or an external source; passing the light through the fiber being produced; positioning the end of the fiber in a holder adjacent to a light detector, for example a photodiode with or without passing the transmitted light through a filter; detecting the light transmitted by the fiber from the light source; converting the detected light into an electrical equivalent signal; amplifying the signal if necessary and recording or observing the changes in the signal to determine an objective measure of the optical fiber's attenuating characteristic.

Abstract: A continuous optical fiber manufacturing process utilizes the method of chemical vapor deposition of the glass forming materials within an R.F. excited glow discharge. The rapid deposition rate within the discharge provides a sufficient stream of glass material for winding into a finished fiber on a synchronous take-up mechanism. Alternate embodiments include an oxygen air stream to remove dust particles from the fiber surface and an in-line fluorine stream to terminate surface bonding and reduce moisture attack on fiber surfaces.