Subject of study. The electrical properties of traveling wave electrodes positioned on a lithium niobate surface are investigated in this study. Method. The investigation methods included the analytical calculation, numerical modeling, and experimental investigation of the amplitude–frequency response and spectra of collinear interaction at the wavelength of 1552 nm. Main results. We demonstrated that traveling wave electrodes with a refractive index close to the refractive index of the optical waveguide should be used when grating periods are shorter than the length of the interaction area. Moreover, in the case of an exact match of the refractive indices, the minimum grating period is mostly limited by frequency-dependent signal attenuation in the electrodes. The effective phase modulation of light at the wavelength of 1552 nm by an electric signal in the band up to 40 GHz was demonstrated. Practical significance. This study determines the parameters of integrated optical circuits, which allow the fabrication of highly effective phase and amplitude light modulators.