Spectrally resolved transmission loss in gamma irradiated Yb-doped optical fibers

Yb³⁺-doped silicate fibers are commonly employed in optical systems utilizing fiber lasers and amplifiers. Deployment of such materials and systems in space-based and other adverse radiation environments requires knowledge of their response to fluxes of ionizing radiation. This paper reports the results of gamma radiation exposures on a suite of passive, modern, highly Yb³⁺-doped aluminosilicate fibers. Of interest are the effects of total dose and dose rate as well as the development of radiation-induced absorption across a broad spectral window (1.0-1.7 μm). Results indicate that these fibers exhibit reasonable radiation resistance to gamma exposures typical of a five-year low-Earth-orbit environment. Maximum transmittance losses of less than 10% in the 1.0-1.7-μm spectral region for total gamma exposures of 2-5 krad (Si) were observed. In addition, it was found that the dependence of transmittance on radiation dose generally followed a power law that was dependent on dose rate.