Analysis of spectral components in the 1.5 μm emission band of Er3+ doped borosilicate glass

We measured the 1.5 μm emission spectra corresponding to 4I13/2 → 4I15/2 transition of Er3+ in borosilicate glass within the temperature range from 11 to 300 K. The spectral components emitting from the lowest and upper Stark levels of 4I13/2 state were distinguished by analyzing the spectra with normalized area. The effect of optical properties of the spectral components on the 1.5 μm emission bandwidth is investigated. The results indicate that to search for a host with higher spontaneous emission probability of the upper Stark levels of 4I13/2 state for Er3+ ions is very important to broadening of the 1.5 μm emission band. An equivalent model of four-level system is presented and applied to explain the spectral shape and temperature characteristics of the 1.5 μm emission band.