A new interferometer-based optical sensing platform with nanostructured thin films of ZrO2 or TiO2 as sensing environment has been developed. With the application of an IC compatible Si(3)N(4) waveguide technology, Mach-Zehnder interferometer devices have been fabricated. The application of the glancing angle deposition technique allowed fabrication of nanostructured thin films as the optical sensing environment. Sensing ability of fabricated devices has been demonstrated through the refractive index measurement of a known gas. The transmission spectra and time response measurements have demonstrated a maximum phase shift of Delta phi=pi/10 and a |Delta P(out)|=0.65 dBm. Devices with TiO2 film on the sensing region performed much better than devices with ZrO2, with sensitivity twice as high.