NIR luminescence from Er–Yb, Bi–Yb and Bi–Nd codoped germanate glasses for optical amplification

Abstract

In this paper, we present the near-infrared luminescence from Er–Yb, Bi–Yb, Bi–Nd codoped germanate glasses. Compared with Bi-doped glass, Bi–Yb codoped glass has shown broad infrared luminescence under 800 nm excitation wavelength. The near-infrared spectra of Er 3+–Yb 3+ and Bi and Bi–Yb codoped glasses have shown full width at half maximum (FWHM) around 80 nm, 240 nm and 300 nm, respectively, under 980 nm and 800 nm LD. The absorption band of the Yb 3+ ion was located around 980 nm. Though the absorption band of Yb 3+ does not interact directly with the incident light at 800 nm, near-infrared emission intensity has been highly increased in Bi–Yb codoped glass. We explained the relevant mechanism for the observed enhancement in the near-infrared emission intensity of Bi doped glass with Yb codoping under 800 nm excitation. The measured lifetimes of Bi, Bi–Yb codoped glasses were 490 μs and 815 μs, respectively. The maximum stimulated emission cross sections for 1188 nm and 1258 nm emission bands of Bi and Bi–Yb codoped glasses were 9.003 × 10 −21 cm 2 and 5.445 × 10 −21 cm 2. These Er 3+–Yb 3+, Bi–Yb and Bi–Nd codoped glasses are promising materials for broadly tunable laser sources and broadband optical amplifiers.