The mechanisms of radiation-induced absorption in silica optical fibers in the visible spectral region and in the telecom spectral windows as well as the technological means to lower the induced absorption are analyzed. Hydrogen loading of large-core silica optical fibers is shown to drastically reduce the induced absorption at megagray doses. It is shown that low-dose transient absorption can degrade the performance of pure-silica-core fibers at (lambda) approximately 1.55 micrometers . N-doped silica fibers are argued to be the best candidates for low-dose applications (e.g. in space). At megagray doses, the long-wavelength induced absorption is found to be the main induced absorption mechanism. Its origin is not known with certainty, whereas its value may be different in pure-silica-core fibers obtained under different preform fabrication conditions. Different types of radiation-sensitive fibers are investigated with the aim to develop fiber-optic dosimeters. An optimum wavelength region for the operation of P-doped silica fiber dosimeters has been determined. Novel types of dosimeters and neutron detectors are proposed based on the effect of irreversible radiation-induced increase of OH- group absorption.