Modeling degraded performance metrics of optical amplifiers under radiation
Gain, noise figure (NF), and output power are considered the common performance metrics of an optical fiber amplifier. With an increasing interest of space industry in developing technologies for satellite-ground and intersatellite communication in the optical band, the EDFA (erbium doped fiber amplifier) is needed as power amplifier in space to compensate attenuation and insertion losses between the building blocks of the architecture. There is very little research on modeling the degradation mechanisms of typical commercial fibers, specifically on the NF and output power metrics, that requires knownledge of the insertion losses at the entrance of the fiber for both the pump and the signal wavelengths λp and λs. In this brief report we propose that the noise figure and output power trends can be extrapolated from a semi-empirical model for the insertion losses proved at high and low dose rates at two different temperatures. The results show reasonable trends that a common offthe shelf EDFA can present in co-propagating configuration on the NF and output power under several doses at low and high rates. The radiation losses using non-hardened fiber show sustainable attenuation levels in dB that can possibly allow employing this off-the shelf fibers in CubeSats or small satellites without the need of special radiation insulation. It is further supported with theoretical data that the temperature factor can affect more the EDFA degradation in space than the radiation itself, imposing limits on the temperature control of commercial satellites using this photonics.