Low‐loss optical waveguides have been produced inz‐cut Sr0.6Ba0.4Nb2O6(SBN:60) and electro‐optic modulation has been demonstrated at a wavelength of 1.3 &mgr;m. The refractive index increase responsible for waveguiding results from a strain produced by a SiO2film which has been deposited on the surface of the substrate at 320 °C. The waveguides are formed in the crystal by dry etching of channels in the strain film. The resulting optical waveguides support both polarizations. Propagation loss values of 0.7 dB/cm for TM polarization and 1.6 dB/cm for TE polarization were measured. Electro‐optic modulation up to 22 MHz was performed on repoled samples using coplanar electrodes. ©1995 American Institute of Physics.