For undersea cables radiation doses between 2.5 and 25 rad are to be expected during a working life of 25 years. The majority of previous investigations of the radiation sensitivity of optical fibers, however, apply dose rates /spl gsim/1 rad/s and total dose values /spl gsim/3/spl times/10/sup 3/ rad. The present paper describes /sup 60/Co irradiations of a Ge-doped single mode fiber with dose rates between 10/sup -4/ and 20 rad/s. Expected loss increase of an undersea optical fiber cable at 1550 nm wavelength with a temperature of 2/spl deg/C is derived by three different methods. The most comfortable and reliable one, the 'dose rate transformation method', yields, for example, a loss of only 0.0244 dB/100 km after 25 years of irradiation with a dose rate of 0.4 rad/s. This method could be the basis of a standard test procedure for the effect of natural radioactivity on optical fibers for very long repeaterless terrestrial and undersea cables.
No takes yet. Share an insight, caveat, or question.
Henschel et al. (1996) studied this question.