Abstract: This invention involves optical fiber which supports essentially only a single guided mode, perhaps degenerate, at the transmission wavelength, usually between 0.6 and 1.7 microns. The index of refraction of the core material is graded in the radial direction so as to yield an optical fiber with very low total dispersion and therefore high bandwidth. Specific embodiments include, in addition to the low dispersion characteristic, improved field confinement, and therefore permit lower clad-to-core ratios then heretofore believed practical. Additional advantages which accrue as a result of the greater field confinement include lower cabling, microbending, and curvature-induced losses.

Abstract: A gold plating process is described in which gold concentration is monitored by a radioactive excitation procedure. This procedure for measuring gold concentration requires no chemical manipulation and yields immediate results. The procedure can be adapted to continuous concentration measurement for use in automatic control of gold concentration in a gold plating procedure.

Abstract: A method of practicing the MCVD process is disclosed. In the inventive process, the core deposition is completed prior to completion of the cladding. An intermediate preform structure with a core-to-clad ratio greater than that desired in the ultimate fiber is consequently obtained. Subsequent to internal core deposition, additional material is added externally to complete the cladding thereby yielding an optical fiber preform with the desired core-to-clad ratio.