Abstract
High-power fiber-optic amplifiers are essential for optical communications in space. Specifically, erbium
and ytterbium co-doped fibers (EYDFs) are key to amplifying a signal power over 10 W. However, cosmic
radiation degrades a general EYDF. Doping the EYDF with cerium reportedly mitigates the radiation-
induced degradation. This paper shows that germanium-doped EYDF successfully amplifies output
power over 10 W with radiation tolerance. These results contribute to progress in spaceborne high-power
optical amplifiers and optical communication in space.
