Thermo-acoustic Phase Modulator based on Y36-cut LiNbO3 Thin Film

Microwave acoustic components have higher quality factors and less crosstalk than electromagnetic components. Efficient modulation of acoustic devices is essential for building large-scale multifunctional acoustic circuits. Here, we demonstrate a thermo-acoustic phase modulator based on a Y36-cut LiNbO
3
(LN) thin-film platform. The proposed structure integrates a 460 MHz SH
0
mode acoustic delay line (ADL) with an on-chip microheater for locally changing the temperature and thus controlling the phase of the ADL. Using this approach, we achieve a phase change of more than 281° at a heating power of 20 mW, and a modulation ability of 17 °/mW in the linear modulation range, which is 6.5 times improvement over previously reported bulk-LN platforms. Our thermo-acoustic modulators enable reconfigurable acoustic signal processing for next-generation wireless communication and microwave systems.