Low-driving-voltage LiNbO3 optical modulators with millimeter-wave bandwidths

Traveling-wave-type LN modulator structures, which achieve a low driving voltage and a large bandwidth, have been presented. As a result, under the velocity match conditions, a higher performance LN modulator can be obtained by utilizing a wider gap or a thinner buffer layer for the ridged z-cut LN substrate, and by utilizing a wider center electrode or a narrower gap for the thinned x-cut LN substrate. These LN modulators are expected to have a sufficient capability for use in millimeter-wave-band optoelectronic systems.