Gamma radiation effects on plastic optical fibers

We report on our study of the effect of gamma-ray irradiation on Plastic Optical Fibers with a 1 mm diameter for short reach communication. For the study, we used gamma-radiation facilities with 60Co sources for slow long-term irradiation with a low dose speed of around 70 Gy/hrs and a maximum dose up to 62.90 kGy and a higher speed irradiation dose of around 1 kGy/hrs with a maximum dose up to 51.30 kGy. The optical losses measurement showed that the losses increased linearly during the irradiation and began to decrease immediately after the end of being irradiated. Higher doses of irradiation cause a higher value of the optical loss, and at the dose of 62.9 kGy, the loss was unmeasurably high. A low dose of gamma radiation (1.24 kGy) increased optical losses only slightly and the gamma-ray irradiation at 17.6 kGy for the 20 m long fiber had optical losses of-15.5 dB at 650 nm. The results of the relaxation measurements also showed that optical losses measured at wave-length 535 nm are significantly higher than those at 650 nm. Spectral characteristics measurement done during the irradiation showed that the intensity of the transmitted light decreased and the absorption edge shifted towards the higher wavelengths. Spectral characteristics measured after irradiation during the relaxation period showed that the intensity increased and also that the absorption edge was shifted towards the lower wavelengths, but the same values as before the irradiation were not achieved.