OPTICAL FIBER BASE MATERIAL THAT HAS THERMAL CONDUCTIVITY VARIATION IN RADIAL DIRECTION AND ITS MANUFACTURE

摘要

Disclosed is an optical fiber capable of preventing an increase in an optical loss from occurring during fabrication and extraction of a single mode fiber preform and enhancement of an optical transmission efficiency, a method of producing the same comprising the steps of forming a first quartz robe having a first thermal conductivity, said first quartz tube being used as a clad; depositing a core layer and a clad layer inside the first quartz robe to form a preliminary perform by heating of the fist quartz robe; forming a second quartz tube having a second thermal conductivity lower than the first thermal conductivity; and depositing the second quartz tube to said preliminary preform by heating to produce the optical fiber preform. On embodiment, uses N overclad layers having thermal conductivites Kx such that K0>K1>K2 . . . >KN and coefficients of viscosity mu 0< mu 1< mu 2 . . . < mu N.