Direct UV patterning of waveguide devices in AS2Se3 thin films

Photodarkening of thermally evaporated amorphous As2Se3 chalcogenide thin films was generated by a UV mercury light source in a standard mask aligner. The refractive index modification of the chalcogenide glass was determined by applying Swanepoel's method. Index changes of + 0.04 were obtained for 500 s exposure. Using these photoinduced index changes, waveguides with losses of approximately 1 dB/cm at 980 nm were fabricated. Another set of waveguides was fabricated by UV exposure and subsequent selective etching to form rib structures. Those waveguides exhibited loss of approximately 2 dB/cm at 980 nm. Silver photodoping of As2Se3 was also performed on a mask aligner. with index increases on the order of 0.3 obtained. Due to the rapid and large photomodification obtainable with standard photolithographic equipment, these processes are promising for integrated optic device fabrication. (C) 2004 American Vacuum Society.