Acoustoelectric-Driven Frequency Mixing in Micromachined Lithium Niobate on Silicon Waveguides

This work reports on frequency mixing due to phonon-electron coupling (acoustoelectric effect) in lithium niobate (LN) on silicon (Si) micromachined Lamb mode waveguides. To study passive RF signal mixing in micro-acoustic domain, two-tone measurements are performed on said heterostructured waveguides. The results confirm the mixing is mainly due to the charge carriers in Si and is intensified as the input power level is increased. Furthermore, the mixed frequency components that lie outside of the design passband of the waveguide are also detected which is an indication of strong acoustic mixing. The preliminary results confirm the possibility of using the phonon-electron coupling in properly designed LN-on-Si waveguides for implementation of micro-acoustic mixers.