An interferometric modulator with Ti-diffused LiNb03 waveguide has been fabricated. Modulation experiments were made at the optical wavelength of 0.6328μm using square wave signal of 1kHz, pulse signal of 50kHz and sine wave signal of 100 kHz-30 MHz.Kxperimental results are as follows: maximum modulation degree-87%, π phase voltage-Vπ = 45 V (peak to peak), eapacitaneo-8 pf and 3 db bandwidth at 800 MHz.