1.53 µm luminescence properties of Er3+-doped K–Sr–Al phosphate glasses

Trivalent erbium (Er3+)-doped K–Sr–Al phosphate glasses were prepared and studied their spectroscopic properties as a function of Er2O3 concentration. Judd–Ofelt analysis has been carried out for 1.0 mol% Er2O3-doped phosphate glass and in turn radiative properties have been evaluated for the excited levels of Er3+ ion. The radiative lifetime for the 4I13/2 level was found to be higher for the present glass when compared to other Er3+-doped glasses. The Er3+-doped glasses exhibit intense near infrared emission at 1.53 µm corresponds to 4I13/2→4I15/2 transition as well as green emission at 546 nm corresponding to 4S3/2→4I15/2 under 980 nm and 488 nm excitations, respectively. The emission cross-section spectrum for 1.0 mol% of Er2O3-doped glass has been evaluated using McCumber theory. The gain cross-section has been evaluated as a function of population inversion, which revealed that the lasing action would be achieved at 1.53 µm for a population inversion about 40%. Decay curves for the 4I13/2 level were measured and lifetimes have been determined for the studied glasses. The results indicate that the present glasses could be useful for laser as well as optical amplifiers at 1.53 µm.