Non-linear optical properties of chalcogenide glasses in the system As-S-Se

We report results of a systematic study examining the relationship of bond type and concentration to the linear and non-linear optical properties of As-S-Se glasses. The effects of iso-structural substitution of Se for S and the resulting impact on structure and the non-linear refractive index, n(2), are discussed. Non-linear optical properties of As-S-Se chalcogenide glasses were measured by the Z-scan technique at 1.6 mu m, and measured n(2) up to 400 times the n(2) for silica were observed. Such large n(2) for glasses with small As/(S + Se) molar ratios is correlated with the presence of covalent, homopolar Se-Se bonds in the glass structure as identified by Raman spectroscopy, and can not be attributed to any red shift in the absorption edge or to a resonant effect. The suitability of these glasses for planar waveguides based on such nonlinear properties is thus confirmed, and recent fabrication results are described. (C) 1999 Published by Elsevier Science B.V. All rights reserved.