Rayleigh scattering of silica core optical fiber after heat treatment.

We investigated the Rayleigh scattering of silica core optical fibers, parts of which were heat treated at various temperatures, in relation to their fictive temperatures (T(f)). The scattering intensities from short fiber segments were clearly reduced by heat treatment compared with those of the unheated parts. The T(f) values of the heated parts of the fibers were determined by measuring the infrared reflection spectrum for cleaved end surfaces and were also reduced by controlling the heating temperature. The reduction in the scattering intensity correlates well with the reduction in T(f).