Process for fabricating a optical fiber preform.

摘要

The process comprises repeatedly depositing inside a quartz reaction tube a soot-like core forming glass (26) at different temperatures, by which a distribution of a doping concentration in the radial direction of the core can be set as desired.

A modification to the process comprises forming two constricted portions (28) at opposite ends of a quartz reaction tube (4), charging a solution of a compound of a rare earth element as a solution into the section of the tube between the constricted portions (28) for doping. By this method, the doping concentration becomes uniform along the length of an optical fiber preform (30) with defects being rarely produced and without any complicated operation.