Transient SEUs in a fiber optic system for space applications

The results of an investigation on the SEU sensitivity for a fiber optic operating system are reported. Measurements were made on the upset cross sections for the system in static and dynamic modes of operation. The heavy ion SEU test facility at Brookhaven and the proton facility at Harvard University were used in this study. Cross sections were obtained for Honeywell transmitter and reciever devices operating in a system at a frequency of 100 kHz. Both devices were independently irradiated. The results show that the dynamic mode was the worst case, and the receiver was the most sensitive part type in the system. The threshold linear energy transfer (LET) for the receiver was determined to be 1.6 MeV sq cm/mg for the three input signals used in the tests, which were: a continuous high state, a low state, and a 100 kHz square wave.