Bulk-film structural differences of chalcogenide glasses probed in situ bynear-infrared waveguide Raman spectroscopy

Thin film devices based on chalcogenide glasses (ChGs) are attractive for i ntegrated optics applications due to their good infrared transmission and h igh nonlinear Kerr effects. To reveal structural variations which impact ph ysical properties depending on material processing and in-use laser conditi ons we employ waveguide Raman spectroscopy (WRS) in ChG thin films and fibe rs using excitation in the near-infrared (NIR). The Raman spectra reveal si gnificant microstructural differences between fibers drawn from bulk As2S3 glasses and unannealed films in that the latter contain As4S4 molecular sub units, The high signal-to-noise ratio and the absence of undesired photorea ctions make NIR WRS a versatile new approach to in situ characterization of infrared waveguide devices. (C) 2001 Elsevier Science B.V. All rights rese rved.