Method of splicing two optical fibers

Abstract

Two optical fibers to be spliced are prepared, coatings of resin are removed from end portions of the respective optical fibers to expose glass fibers, the glass fibers are aligned to each other, an a fusion step is carried out to heat the end faces of the glass fibers to cause fusion thereof to form a fusion-spliced portion. After that, an additive-diffusing step is carried out to diffuse an additive added in the glass fibers around the fusion-spiced portion, by a heat treatment around the fusion-spliced portion, by a heat treatment around the fusion-spliced portion at a first temperature of not less than 800° C. nor more than 1500° C. Further after the additive-diffusing step, a thermal-strain-removing step is carried out to remove thermal strain by a heat treatment of a wider region than heated regions in the fusion splice step and in the additive-diffusing step of the fusion-spliced portion, at a temperature of not less than 500° C. nor more than 1200° C.

Dependencies are inferred from the claim text.