Optical fibers for high radiation dose environments

Even in environments with extremely high radiation exposure such as nuclear reactors, nuclear fuel reprocessing facilities, high energy physics accelerators, or space satellites the use of optical fibers can be advantageous because of their low weight, high bandwidth, electrical isolation, and heat resistance. In this paper, a variety of modern single mode (SM) and graded index (GI) fibers as well as a new pure silica multimode step index (MMSI) fiber with high OH content were irradiated at a 60Co gamma ray source with a dose rate of ∼ 1.5Gy/s up to a total dose of 106Gy. The radiation-induced loss of all fibers was measured continuously during and after irradiation at discrete wave-lengths (∼850, ∼1,070, ∼1,300, ∼1,550nm). With one SM fiber type also the ''breaking stress'' before and after irradiation was determined. Radiation-induced losses of approx-lt 5dB/50m (at ∼1,300nm) were found with some of the SM fibers, whereas the MMSI fiber showed a final induced loss of only 0.5dB/50m at 1070nm wavelength. The breaking stress of the SM fiber increased by about 10%