Studying pump light-induced darkening in erbium-doped fiber amplifiers with optical time domain reflectometry

A simple technique using optical time domain reflectometry at 1300 nm was developed to measure possible 1480 nm pump light-induced darkening in erbium optical fiber amplifiers. A single Er/sup 3+/-doped fiber (EDF) was spliced between two undoped fibers and continuously exposed to approximately 0.7 MW/cm/sup 2/ at 1480 nm. The attenuation of the EDF was periodically monitored for any transmission changes. During a period of 85 days no change was observed within the long term accuracy of this method ( approximately=0.02 dB).<
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