LASER-GENERATED ULTRASONIC CHARACTERIZATION OF IRRADIATED GLASS OPTICAL FIBERS

Glass optical fibers were irradiated from 100 krad (Si) to 1 Mrad (Si) with gamma radiation from a cobalt-60 source. The irradiated fibers w ere characterized with laser-generated ultrasonics as well as electron spin resonance techniques. Phosphorus- and germanium-based color cent ers were observed in the exposed fibers, and the intensity of the colo r centers was found to increase as the fibers were exposed to larger r adiation doses. The extensional wave speed was found to decrease with increasing radiation exposure owing to elastic softening of the fiber. A linear relationship was inferred between the electron spin resonanc e intensity and the extensional wave speed.