Effects of Low-Dose-Rate Radiation on Opto-Electronic Components and the Consequences upon Fiber Optic Data Link Performance

Tests have been performed to examine the effects of low-dose-rate radiation exposure on opto-electronic components that can be used in the implementation of 20-Mbps digital fiber optic data links. Three important effects were studied: 1. Exposure of PIN photodetectors to a flux of ionizing particles produces current pulses which would cause false events or increased rms noise in the link. 2. The accumulation of total dose by the fibers produces increased attenuation. When exposed at a low dose rate for a period of time, a complicated recovery process occurs at the same time as the damage production. The result is that the amount of attenuation produced depends on the dose rate. 3. Exposure of GaAlAs light-emitting diodes to a proton fluence causes an unexpectedly large and permanent degradation in light output. To determine the consequences of these effects on data link performance, a link was designed for spaceborne applications and the failure thresholds examined.