Reduction of photodarkening in Yb/Al-doped fiber lasers

Magnus Engholm; Lars Norin

doi:10.1117/12.763218

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25 February 2008 Reduction of photodarkening in Yb/Al-doped fiber lasers

Magnus Engholm, Lars Norin

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Proceedings Volume 6873, Fiber Lasers V: Technology, Systems, and Applications; 68731E (2008) https://doi.org/10.1117/12.763218
Event: Lasers and Applications in Science and Engineering, 2008, San Jose, California, United States

Abstract

A strong charge-transfer band at UV-wavelengths is found to play a major role for the observed induced optical losses (photodarkening) in ytterbium doped high-power fiber lasers. This is correlated to the valence stability of the ytterbium ion in the silicate glass matrix, which we believe is the origin of photodarkening. We have performed UV-irradiation experiments on ytterbium-doped preform samples and accelerated photodarkening experiments on Yb-doped fibers, by using 915 nm high power diodes. Our results show that photodarkening can be reduced, to low levels, either by preparing the preform glass in a reducing atmosphere or by hydrogen loading the fiber in a pressure chamber at room temperature.

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Magnus Engholm and Lars Norin "Reduction of photodarkening in Yb/Al-doped fiber lasers", Proc. SPIE 6873, Fiber Lasers V: Technology, Systems, and Applications, 68731E (25 February 2008); https://doi.org/10.1117/12.763218

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