초록 ▼

A method is disclosed for making a step-index optical fiber having a steep refractive index gradient between core and cladding. Core glass particles comprising a base glass and a refractive index-increasing dopant are deposited on a mandrel. The mandrel is removed and the resultant soot preform is c

A method is disclosed for making a step-index optical fiber having a steep refractive index gradient between core and cladding. Core glass particles comprising a base glass and a refractive index-increasing dopant are deposited on a mandrel. The mandrel is removed and the resultant soot preform is consolidated to form a core preform having a dopant-poor surface region. The core glass preform is stretched and the hole therein is closed to form a core bait rod. Cladding glass soot is deposited on the core bait rod at a density which is at least 0.5 g/cc. This is accomplished by directing the flame from an auxiliary burner onto the core bait rod immediately prior to the deposition of cladding soot thereon. The resultant preform is consolidated and drawn into an optical fiber. In another embodiment, the etched core preform is overclad with a layer of cladding glass, and the composite preform is stretched prior to applying a second overclad layer.

대표청구항 ▼

A method of making an optical fiber preform comprising forming a glass rod the composition of which includes a base glass and at least one dopant, the concentration of said dopant changing radially from an acceptable level within said rod to an unacceptable level in a surface layer of said rod, imme

A method of making an optical fiber preform comprising forming a glass rod the composition of which includes a base glass and at least one dopant, the concentration of said dopant changing radially from an acceptable level within said rod to an unacceptable level in a surface layer of said rod, immersing said rod in an etchant to remove said surface layer, the step of etching being sufficiently severe that it results in the formation of etch pits in the surface of said rod, heating and stretching said rod to smooth said etch pits and provide a better surface on which to deposit cladding soot, the step of stretching resulting in the formation of an elongated core bait rod, and thereafter applying to said rod a layer of glass having a composition different from that of said rod by depositing a plurality of layers of particles of glass on said elongated core bait rod and heating the resultant assembly to consolidate said glass particles and form said layer of glass.