Optical properties of Er3+ doped alkali-chloro phosphate glasses for optical amplifiers

A new class of Erbium doped glasses with compositions xNa2O - (60-x)PbCl2 - 40P2O5 (x=0, 10, 20 and 30) were fabricated and characterized for optical properties. Absorption spectra were analyzed for important Judd-Ofelt parameters from the integrated intensities of various Er3+ glass absorption bands. Photoluminescence (PL) and its decay behavior studies were carried out for the transition 4I13/2 -> 4I15/2. A systematic correlation between the Judd-Ofelt parameter {omega}2 and the covalent nature of the glass matrix was observed, due to increased role of bridging oxygens in the glass network. The PL broadness and life times of 4I13/2_> 4I15/2 transition were typically in the range of 40-60nm and 2.13-2.5ms respectively. These glasses broadly showed high transparency, high refractive index, shorter life times and, most importantly, these glasses were found to be capable of being doped with larger concentrations of Er3+ (up to 4 wt%). Increase of Er3+ concentration resulted in the increase in PL line-widths with no significant effect of concentration quenching, indicating that these glasses are suitable for optical fibre/waveguide amplifiers.