LiNbO3 Thin-Film Modulators Using Silicon Nitride Surface Ridge Waveguides

Lithium niobate (LiNbO3) is an excellent electrooptic material due to its low loss, large electrooptic coefficient, linear modulation response, and large modulation bandwidth. In this letter, we present the first LiNbO3 thin-film Mach-Zehnder optical modulator that employs silicon nitride surface ridge optical waveguides. The modulator contains a 1.2-cm-long push-pull phase modulation section and a pair of multimode interferometric 3-dB couplers. It demonstrated V-pi . L of similar to 3 V . cm and a 3-dB bandwidth of similar to 8 GHz.