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

Thin film devices based on chalcogenide glasses (ChGs) are attractive for integrated optics applications due to their good infrared transmission and high nonlinear Kerr effects. To reveal structural variations which impact physical properties depending on material processing and in-use laser conditions we employ waveguide Raman spectroscopy (WRS) in ChG thin films and fibers using excitation in the near-infrared (NIR). The Raman spectra reveal significant microstructural differences between fibers drawn from bulk As2S3 glasses and unannealed films in that the latter contain As4S4 molecular subunits, The high signal-to-noise ratio and the absence of undesired photoreactions make NIR WRS a versatile new approach to in situ characterization of infrared waveguide devices. (C) 2001 Elsevier Science B.V. All rights reserved.