HIGH-SPEED CUTOFF MODULATOR USING A TI-DIFFUSED LINBO3 CHANNEL WAVEGUIDE

A high-speed intensity modulator has been fabricated taking advantage of the dependence of waveguide cutoff on its index of refraction. The modulator consists essentially of a 2-μm-wide 3.2-mm-long Ti-diffused channel waveguide in y-cut LiNbO3. By controlling the propagation cutoff through the electro-optic effect, an intensity modulation is obtained. The potential bandwidth, optical insertion loss, and specific energy at 0.63 μm are 5.3 GHz, 11 dB, and 230 μW/MHz, respectively. A brief analysis of modulator operation is given based on coupled-mode theory.