Bi-doped glasses for broadband fiber light source

摘要

Bi-doped silica glass is a new broadband infrared fluorescence material. We drew optical fibers with the Bi doped silica glass for the fiber core and evaluated the fluorescence spectrum. The FWHM of fluorescence spectrum is measured to be 390 nm. When this broad band spectrum is used as an OCT light source, the expected axial resolution is calculated to be 1.9μm, This is comparable to the axial resolution (△z～1μm) by Ti:Al_2O_3 system. And we also examined the local structure of Bi ion in Bi-doped silica glass. These are analyzed by ESR, EXAFS, XPS, and ~(27)Al-NMR. According to these results, the structural model of Bi luminescent center is proposed that Bi~(5+) ion with 6-fold coordination exists close to Al~(3+) ion with 6-fold coordination.