Comparative study of spectroscopic properties of Er³⁺-ion doped K₂O/KF-Gd₂O₃-P₂O₅ glass systems

The two phosphate glasses with composition 17K 2 O−17Gd 2 O 3 −65P 2 O 5 −01Er 2 O 3 and 17KF−17Gd 2 O 3 −65P 2 O 5 −01Er 2 O 3 composition were synthesized by conventional-melt quenching techniques to study comparatively the spectroscopic, Judd–Ofelt (JO), radiative properties and NIR-luminescent properties. The Urbach energy of K 2 O−Er and KF-Er samples was 0.3547 and 0.4799 eV. The observed trend is Ω 2 >Ω 4 >Ω 6 and Ω 2 >Ω 6 >Ω 4 for JO-intensity-parameters for K 2 O−Er and KF-Er glasses. Moreover, K 2 O−Er has higher Ω 4 and Ω 6 values, thus having more rigidity and viscosity than KF-Er. The measured values of full-width-half-maximum (FWHM) for K 2 O−Er and KF-Er glasses 54.60 and 58.27, respectively. The measured values of FWHM for K 2 O−Er and KF-Er glasses were 54.60 and 58.27, respectively. The A R values are 417.61 and 3038 for K 2 O−Er and KF-Er glasses, respectively. The radiative lifetime ( τ R ) for K 2 O−Er and KF-Er glasses is 2.39 ms and 3.18 ms, respectively. Utilizing McCumber theory the G ( λ , β ) is positive and population-inversion is more than 0.4 for both glasses. Both samples have flat gain-bandwidth in the range of 1505–1585 nm, which covers the S-, C-, and L-bands of the low-loss optical communication-window. It is evident from all these results that the prepared glass samples have the potential for a low-threshold and high gain NIR laser and optical-fiber amplifier.