LiNbO₃Thin-Film Modulators Using Silicon Nitride Surface Ridge Waveguides

Abstract

Lithium niobate (LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) 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 LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> · L of ~3 V · cm and a 3-dB bandwidth of ~8 GHz.