Effects of melting temperature and composition on spectroscopic properties of Er^3+-doped bismuth glasses

Abstract

The spectroscopic properties (SPs) of bismuth glasses are strongly influenced by the preparation conditions. Here, we studied the effects of melting temperature and concentration ratio of Bi2O3 to SiO2 on the SPs of Er3+ doped Bi2O3-B2O3-SiO2 bismuth glasses. We have shown that the low melting temperature is preferable to achieve large and broad gain of Er3+ ions. When melted at high temperatures, however, the glasses get darkened which is against the application of these materials for optical fiber amplifiers. On the other hand, we have also shown that a compromise has to be made between the laser gain and threshold regarding the optimum concentration ratio of Bi2O3 to SiO2. Theoretical radiative transition rate and quantum efficiency of the 1.55 μm emission of Er3+ have been obtained by Judd-Ofelt (JO) fitting. The variation of the JO parameters characterizing the local chemical environments around Er3+ can be explained based on the concept of optical basicity.