Method of producing optical fiber preform.

摘要

A method of producing a preform for a single-polarization optical fiber wherein a glass rod 3 which in the fiber is to be a core or a glass rod which is to be a clad and a core is inserted into a quartz tube 1 which has on its inner wall surface (a) a thin glass film 2 which is to be a clad layer, (b) a thin glass film which is to be a jacket layer or (c) thin glass films which are to be a jacket layer and a clad layer. Then, with its internal pressure reduced, the tube 1 is heated to become solid, so that at least one of the clad and the jacket of the optical fiber preform becomes elliptic in cross section.