Interpretation and method of decreasing drawing-dependent optical losses in germanium-doped silica optical fibers

It is well known that optical losses of germanium-doped silica- core optical fibers (OF’s) depend on drawing conditions.1-3 In a single-mode OF losses increase when the temperature is increased or the speed is decreased during the drawing process. The drawing-induced losses are caused by the Ge-related defects in the core,3 but their origin is not known. In this paper we submit an interpretation that is quite valid for explaining all the known drawing-condition effects on initial fiber losses. On the basis of this model we propose and confirm experimentally a method for decreasing the drawing-induced loss. The proposed interpretation is based on results45 concerning the defect properties of Ge-doped silica glass.