The spectroscopic investigations show that small amounts of oxide (∼1%) in low-oxide-content sulphide glass create a second group of sites with a local environment different than that of the main sulphide sites. Dy3+ ions in the oxide site, which can constitute up to approximately one third of the total number of Dy3+ ions, experience a high-phonon-energy environment and do not show any 1.3-µm emission and hence cannot provide gain for a potential 1.3-µm optical-fiber amplifier in this material.