Technology and performances of silicon oxynitride waveguides for optomechanical sensors fabricated by plasma-enhanced chemical vapour deposition

The technology and performances of a micromachined channel waveguides, based on PECVD deposition of silicon oxynitride (SiOxNy) thin films, is presented. The deposition parameters of the PECVD process are studied in connection with their optical, mechanical and chemical properties. Waveguide deign is optimized allowing single mode, low loss propagation and high efficiency of coupling with single mode optical fiber. The proposed technology is applied to fabricate the pigtailed Mach-Zehnder interferometers, where the coupling from optical fiber to waveguide is based on the etch of U-grooves, supporting fibers in the same substrate as the waveguide substrate.