Low drive voltage, broad-band LiNbO/sub 3/ modulators with and without etched ridges

Frequency dependent drive voltage is reported in velocity matched, packaged, Mach-Zehnder interferometers, made on Z-cut, Y-propagating LiNbO/sub 3/, with and without etched ridges. Drive voltages of /spl sim/7 V at 40 GHz are demonstrated, with the etched ridge device showing a 1/2-1 V advantage. Microwave modeling allowed the extraction of the effects of dispersion in material properties, occurring near the acoustic resonance, on bandwidth and drive voltage.