Study On Optical Properties Of As₂S₈ Amorphous Semiconductor Films Waveguide

Chalcongenide semiconductor glass is one of the best potential materials of all-optical switching, it has a wide field of applications in optoelectronic integrated devices such as infrared electro-optic modulator, all-optical devices of optical communication band and so on, for its large nonlinear refractive index, wide infrared transmission window and good glass forming ability. This article studies the optical properties of AS2S8 amorphous semiconductor thin film waveguide upon light irradiation and annealing, mainly for the changes of its refractve index and thickness.This paper focuses on the exoperimental study of the changes of refractive index and thickness of the As2S8 amorphous semiconductor thin film waveguide upon processes of light irradiation and anealing. We observe the effect of refractive index increase of As2S8 amorphous semiconductor thin film irradiated by UV-light. The refractive index increase verge to saturation point with the irradiation time increase, and reach saturation point after 70 minutes. On the other hand, the annealing process is used to study the refractive index increase effect of as-deposited AS2S8 film, the refractive index increase induced by annealing of As2S8 film is found significant when the annealing temperature exceeds 160℃. Also, we observe that the thickness of As2S8 film decreases during UV-light irradiation and annealing. The amount of the decrease of thickness caused by irradiation of AS2S8 film tends not to change, while the thickness decrease caused by annealing is found more apparent when the annealing temperature reaches 160℃. In addition, the refractive index of the As2S8 film of irradiation saturation state is observed to be nearly invariant when the annealing temperature is below 160℃, while it is apparently decreasing when the temperature is higher than 160℃. That is to say, the refractive index of AsiS8 film is reversible with the co-action of irradiation and annealing. In addition, the refractive index changes of the AsaS8 film upon the annealing and saturation irradiation and annealing cycles are studied. Also, the refractive index changes of the As2S8 film upon the annealing and non-saturation irradiation and annealing cycles are shown. Based on the above experimental datas, we try to fabricate the AsiS8 glass strip waveguide and study the light propagation property of AS2S8 film waveguide.A good light propagation property with a low propagation loss of 0.76dB/cm is obtained.