Clad index of refraction inequality it possesses more optical fiber preform and its production manner

摘要

PROBLEM TO BE SOLVED: To provide an optical fiber preform which allows the distinct measurement of the boundary between a cored clad and external deposition clad formed in two stages and allows the measurement of a thickness fluctuation and the eccentricity and elliptical shape formation of a cross sectional circular surface and its production. ;SOLUTION: The optical fiber preform formed by enclosing a core rod 2 consisting of a core 3 and the cored clad 4 with the external deposition clad 6 of the same quality as the quality of the cored clad 4 has the nonuniform refractive index layer 5 varying in the concentration of the refractive index regulating dope material included in the clad glass between the cored clad 4 and the external deposition clad 6.;COPYRIGHT: (C)2000,JPO