Suppression of photo-induced effects in chemically stoichiometric Ge26.67Ga8S65.33 glasses

Abstract

We have prepared GexGa8S92-x glasses with x=20, 26.67 and 36, and investigated the photoinduced effects under illumination at sub-bandgap wavelength with different power densities. It was found that, Ge20 and Ge36 undergo photodarkening (PD) and photobleaching (PB), respectively, and the change of transmission ratio with and without illumination increases with increasing illumination power density as well as prolonging illumination time. On the other hand, Ge26.67 is almost optical stable in any cases. This potentially offers a chance to reduce additional optical loss induced by PD and achieve net optical gain in the erbium doped chalcogenide planar waveguide amplifier using chemically stoichiometric Ge26.67 glass.