This report is about the preparation and the optical transmission loss of rf‐sputtered SiO2‐Ta2O5films that are suitable for use as transmission media in integrated optical circuits. It is shown that the films, which can be produced with a refractive‐index range from 1.46 to 2.08 at 6328 A˚ wavelength by suitably selecting the ratio of the target constituents, exhibit a low optical transmission loss of less than 0.8 dB/cm for the TE0mode.