A high-speed integrated-optic Ti:LiNbO3 Mach-Zehnder interferometric modulator for 0.83-μm wavelength operation has been fabricated and characterized. The modulator exhibits smooth, resonance-free frequency response with a 17-GHz 3-dB bandwidth. The modulator has a built-in phase bias of π/2 for maximum linearity. Complete intensity modulation can be achieved with 120-mW drive power. Optical modulation was measured up to 18 GHz directly by using a very high-speed photodiode and indirectly using the swept frequency technique.