CHARACTERIZATION OF GA-LA-S CHALCOGENIDE GLASS THIN-FILM OPTICAL WAVE-GUIDES, FABRICATED BY PULSED-LASER DEPOSITION

The fabrication of stoichiometric thin-film optical waveguides of Ga-L a-S via a pulsed laser deposition technique is reported. Stoichiometri c films are grown by ablating Ga-La-S bulk glass with a KrF excimer la ser (lambda = 248 nm) at an incident laser flux greater than or equal to 3.5 J/cm(2). The composition of the films is determined by energy-d ispersive X-ray analysis and the refractive index is measured by a dar k-mode prism coupling technique. Photoinduced structural rearrangement of the as-deposited films leads to a blueshift in the visible absorpt ion edge and a permanent refractive index change, Delta n, of -1%. On the basis of these results, grating structures have been written with both blue light, and e-beam addressing, and their suitability for inte grated optical structures assessed.