Optical loss mechanisms in GeSiON planar waveguides

A double frequency overtone of the fundamental N-H bond related vibration was found to dominate the optical loss in the 1.5-1.6 mum range in high index GeSiON-based planar waveguides deposited by plasma-enhanced chemical vapor deposition using hydrogen-based precursors. The fundamental N-H bond-related absorption and its double frequency overtone were measured to be similar to560 cm-1 and 1.8 cm-1, respectively, resulting in their ratio of 310+/-10. The optical loss, extracted from analysis of the N-H-related absorption is consistent with the directly measured optical loss in the waveguide structures. It was shown that using the deuterated precursors results in incorporation of N-D bonds in the GeSiON films. The N-H bond absorption band was eliminated in the deuterated films, leading to low optical losses in the communication band. (C) 2002 American Institute of Physics.