Divalent Ytterbium in Ytterbium Doped Aluminosilicate Glass - Aspects on Photodarkening in Fiber Lasers

We show that divalent ytterbium ions are present in ytterbium doped aluminosilicate glass. The presence of Yb2+-ions may influence the formation of induced color centers in ytterbium doped fiber lasers leading to reduced performance.