Er–Yb codoped phosphate glasses with improved gain characteristics for an efficient 1.55 µm broadband optical amplifiers

We have investigated the optical properties of phosphate glasses codoped with Er3+–Yb3+ as a function of Yb3+concentration in order to evaluate their potential as both glass laser systems and amplifier materials. The results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of phosphate glasses. The Judd–Ofelt (JO) model has been applied to absorption intensities of Er3+ (4f11) transitions to establish the so-called Judd–Ofelt intensity parameters: Ω2, Ω4, Ω6. With the weak spectroscopic quality factors Ω4/Ω6 (0.38), we expect a relatively prominent Infrared laser emission. The intensity parameters are used to determine the spontaneous emission probabilities of some relevant transitions, the branching ratio and the radiative lifetimes of several excited states of Er3+ and compared to the equivalent parameters for other host glasses.