Features in the photoluminescence line-shape of heavily Er-doped Ge–S–Ga glasses

Erbium doped chalcogenide glasses are of great interest in the integrated optoelectronic technology due to their Er3+ intra-4f emission at the standard telecommunication wavelength of 1.54 μm. In this paper, the photoluminescence (PL) of a series of (GeS2)x(Ga2S3)100−x (x = 75 and 67) glasses doped with high amounts of Er2S3 (1.8, 2.1, 2.4 and 2.7 mol%) under excitation with 1064 nm light has been studied. A quenching PL effect at 1.22 аt.% Er-doped (GeS2)75(Ga2S3)25 and 1.39 аt.% Er-doped (GeS2)67(Ga2S3)33 glasses has been established. The relative changes in PL line-shape at around 1540 nm have been estimated by deconvoluting the spectra to Gaussian sub-bands centered at 1519 ± 1, 1537 ± 1, 1546 ± 1, 1555 ± 1 and 1566 ± 4 nm, which correspond to F21, F11, F22, F12 and F13 transitions in the 4 I 13 / 2 and 4 I 15 / 2 energy levels and have intensity and manifestation that are strongly depend on the Er-doping level. The influence of gallium on the PL efficiency has been evaluated with a view to enhanced emission cross-section.