Frequency dependent drive voltage is reported in velocity matched, packaged, Mach-Zehnder interferometers, made on Z-cut, Y-propagating LiNbO3, with and without etched ridges. Drive voltages of 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.
W. K. Burns, M. M. Howerton, R. P. Moeller, R. hl, R. W. McElhanon, and A. S. Greenblatt, "Low Drive Voltage, Broad-Band LiNbO3 Modulators With and Without Etched Ridges," J. Lightwave Technol. 17, 2551- (1999)