We present the production and characterization of TeO2-WO 3-Bi2O3 thin films to be used as core layer in the fabrication of optical sensors based on Mach-Zehnder Interferometer (MZI) that has applications as pressure sensors, temperature sensors, chemical and biological sensors. The waveguides were fabricated from pedestal type obtained using conventional optical lithography procedures, followed by plasma etching and Sputtering deposition. Propagation losses around 2.0 dB/cm and 2.5 dB/cm were obtained at 633 and 1050 nm, respectively. Measurements were also performed to characterize the guide modes. Single-mode propagation at 630 and 1050 nm was observed for waveguides width up to 10 μm; larger waveguides width provided multi-mode propagation. © 2013 IEEE.