Transient absorption in optical fibers has been studied with emphasis on fast absorption components. Radiation damage was induced with a Febetron 706 electron accelerator, modified to deliver an electron pulse width of 1.1 ns. Dye lasers were synchronized to the accelerator to provide a light pulse through the fiber during the radiation pulse. The output light pulse was detected with a biplanar vacuum photodiode. Four scope traces were used on each electron pulse to monitor the Febetron output, the input drive pulse, and two records of the output pulse on two sweep speeds. Detailed data were acquired for times less than 100 ns after irradiation. An insulated enslosure was used to vary fiber temperature from -30/sup 0/C to + 250/sup 0/C. Several fibers were studied with emphasis on ITT T303 PCS fiber. Data were acquired at 600 and 850 nm. Theoretical modeling of the data is presented
