Broadband NIR emission in glasses and multicore optical fibers codoped with Ni2+/Cr3+/Bi3+ and rare-earth ions

In the paper, the possibility of obtaining broadband NIR luminescence in germanate glasses and fibers doped with transition metals (Cr, Ni), bismuth (Bi), and rare-earths (RE) has been investigated. In bismuth-doped GGB glasses, the influence of Sb2O3 content on luminescence properties has been studied, and the possibility of drawing glass into fiber. Luminescence at 1.3 mu m with FWHM=209 nm was observed for the glass doped with 3 mol% Sb2O3 and 1.5 mol% Bi2O3. In the next step, the spectroscopic properties of Cr3+ doped GGB glass and optical fiber were investigated. After drawing glass into fiber FWHM ( full with at half maximum) at 1.0 mu m increased from 202 nm to 234 nm compared to bulk glass. Obtained luminescence at 1.0 mu m can be attributed to the T-4(2) -> (4)A(2) transition of Cr3+ ions. For multicore glass-ceramic optical fiber, broadband near-infrared emission in the range of 1.1 to 2.1 mu m was obtained under 940 and 980 nm pump excitation as a superposition of luminescence bands of Ni2+, Er3+, Tm3+ and Ho3+ ions.