Reversible photo-darkening and resonant photobleaching of Ytterbium-doped silica fiber at in-core 977-nm and 543-nm irradiation

摘要: We report experimental results showing novel features in photo-darkening and photo-bleaching of a heavily-doped Ytterbium silica fiber exposed to in-core 977-nm 543-nm irradiation. It is shown that pumping the at resonant wavelength leads an increase absorption spectrally wide range (400–1000 nm, photo-darkening) simultaneous decrease (Yb3+) coefficient near ~ 1 μm (resonant photo-bleaching). Such character spectra transformations allows us propose they are signature light-induced Yb3+ → Yb2+ conversion process, with absorption, or photo-darkening, arise owing centers formation stem from corresponding ions concentration. as well demonstrated exposure fiber, where aforementioned have occurred, light partial return initial properties – bleaching excess loss visible increasing peak. Therefore, we reveal reverse Yb3+, possibly taking place last case.