Fusion neutron damage on optical fibers and optoelectronic devices

Radiation-resistant optical fibers fabricated with purified silica glass were irradiated at room temperature with 14-MeV neutrons from the RTNS-II. The induced loss in light transmission was measured in situ during irradiation. It was found that the fusion neutron response of the optical fibers can be approximately classed in three types as follows: (1) a large induced loss with little recovery; (2) a large induced loss with a quick recovery; and (3) a small induced loss with a saturated tendency. The induced-loss rate has been calculated on the basis of damage components that depend mainly on neutron fluence and show little recovery. Fusion neutron irradiation effects on related optoelectronic devices and their hardness levels are shown. These are the neutron fluences at which important performance parameters of the devices begin to degrade. The data are useful for fiber-optics design for fusion diagnostic systems.<>