Impact of thermal quenching on Bi active center photostability in Bi/Er Co-doped Fiber

The impact of thermal quenching on the photostability of bismuth active center (BAC) is investigated through measuring the photo-bleaching process under 830 nm irradiation in quenched Bi/Er co-doped fiber (BEDF). By fitting with the stretched-exponential model, the emission intensity ascribed to the photostable BAC associated with silica (BAC-Si) at 1400 nm (I( $\infty $ )), unbleachable ratio $(\gamma _{\textrm {UB}})$ and bleaching time $(\tau _{\mathbf {B}})$ are obtained. Compared to the untreated sample, the $\text{I}(\infty) $ increases with higher temperature or a longer dwell time, while both the $\gamma _{\textrm {UB}}$ and $\tau _{\mathbf {B}}$ decrease. The results show that BAC-Si could be bleached faster, while additional amount of BAC-Si could be retained in thermally quenched samples. Besides, the lower photostability of the newly quenching activated BAC, impacted by different quenching conditions, is estimated.