Abstract In a process for continuously producing a light conducting glass fiber wherein the refractive index in a plane perpendicular to the optical axis of the glass fiber is so distributed that it continuously decreases outward from a certain value at the center toward the peripheral portion, a first kind of glass containing ions having a greater degree of contribution to the refractive index is drawn, in molten state from a central orifice to form the core portion of the glass fiber, and another kind of melted glass containing ions having less contribution to the refractive index is drawn from a second orifice to form an outer coating layer of the glass fiber, the tip of the first central orifice being located at a retracted position compared to that of the second orifice with respect to the drawn direction of the melted glasses, whereby thermal mutual diffusion of these ions is caused to occur through a boundary surface between two kinds of glasses located mainly in the distance portion between the tips.
A process according to claim 1, wherein first ions comprise Tl ions and said second ions comprise at least one kind of ions selected from the group consisting of Li, Na, K, Rb, and Cs ions.
Claim 2
Dependent Claim
26 words
A process according to claim 1; wherein said axial length within which both said core and sheath are constricted is more than 5 mm in length.
Claim 3
Dependent Claim
60 words
A process according to claim 1; wherein said axial length within which both said core and sheath are constricted is of a sufficient length to impart a Refractive index distribution to said glass fiber which decreases from the fiber optical axis to the fiber periphery in proportion to the square of the radial distance outwardly from the fiber optical axis.
Claim 4
Dependent Claim
46 words
A process according to claim 1; wherein said axial length within which both said core and sheath are constricted is of a sufficient length to maintain the refractive index of the fiber optical axis at the refractive index value of that of said first melted glass.