Prediction of long-term hydrogen-induced loss increases in Er-doped amplifier fibers

Accelerated hydrogen aging tests have shown that Er-doped amplifier fibers of typical compositions react quickly with even trace levels of H/sub 2/, causing spectrally broad OH loss increases that influence signal and pump wavelengths. These loss increases have been noted in Er fibers made by different techniques and by different manufacturers. Loss increases at 1.55 mu m of 1 to 10 dB per 20-m device are predicted for nonhermetically coated fibers exposed to 0.001 atm of H/sub 2/ for 25 years at normal operating temperatures. These hydrogen induced losses can be prevented by using high-quality hermetic coatings to limit the H/sub 2/ that reaches the reactive fiber core.<
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