Study on the tensile strength of optical glass fiber spliced by arc fusion method

Abstract

Recently, many optical grass fibers are used as the submarine cables because of exellent corrosion resistance, no electromagnetic noise and low transmission loss. The fiber has to be spliced to fabricate a long distance transmission line by the arc fusion method. However, there is a serious problem that the spliced part occasionally break after it is laid as the submarine cable, because the tensile strength of the spliced fiber reducues to about 1/2 than that of the virgin fiber. Therefore, the advance research for regeneration method of tensile strength of the fiber which is spliced by arc fusion is desired. For the above purpose, the position of fiber which was broken by a tensile testing device was measured, and the hardness of fiber's surface was examined throughout to the nonfusion region from the spliced center. And also, the shape and crack of indentation formed by hardness test were investigated. Form the correlation between the Vickers hardness for the distribution of fiber broken position and the growth of lateral crack of indentation, it was found that the main case of tensile strength was brought from a progress of brittleness of glass in the arc fusion.