CRYSTALLIZATION AND OPTICAL LOSS STUDIES OF Dy~(3+)-DOPED, LOW Ga CONTENT, SELENIDE CHALCOGENIDE BULK GLASSES AND OPTICAL FIBERS

摘要

Dysprosiμm (Dy~(3+)) doped GeAsGaSe chalcogenide glasses are a significant candidate for novel mid-infrared fiber lasers beyond 4 μm wavelength. This work is a crystallization and optical loss study of Dy~(3+)-doped GeAsGaSe chalcogenide bulk, as-prepared glasses and Dy~(3+)-doped optical fiber with low Ga content. In the bulk glasses of 0-3000 ppm Dy~(3+)-doped Ge_(16.5)As_(16)Ga3Se_(64.5)(at% (atomic%)), despite none of their X-ray diffraction patterns showing any crystallization peaks, a sub-micron crystal is imaged in the 3000 ppm Dy~(3+)-doped Ge_(16.5)As_(16)Ga3Se_(64.5) glass and analyzed using high resolution transmission electron microscopy to be a modified Ga2Se3 incorporating a small amount of Ge. Extra background optical scattering loss of the bulk glasses is found in Fourier transform infrared spectra. Finally, this work presents the optical loss spectrμm of a 500 ppm Dy~(3+)-doped Ge_(16.5)As_(16)Ga3Se_(64.5) optical fiber, exhibiting 1.16 dB/m loss at 6.56 urn. An X-ray diffraction pattern of the powdered glass of the fiber exhibited small crystallisation peaks despite the low doping level of Dy~(3+).