Low-phase-noise microwave-frequency integrated oscillators provide compact solutions for various applications in signal processing, communications, and sensing. Surface acoustic waves (SAW), featuring orders-of-magnitude shorter wavelength than electromagnetic waves at the same frequency, enable integrated microwave-frequency systems with much smaller footprint on chip. SAW devices also allow higher quality (Q) factors than electronic components at room temperature. Here, we demonstrate a low-phase-noise gigahertz-frequency SAW oscillator on 128{\deg}Y-cut lithium niobate, where the SAW resonator occupies a footprint of 0.05 mm2. Leveraging phononic crystal bandgap-edge modes to balance between Q factors and insertion losses, our 1-GHz SAW oscillator features a low phase noise of -132.5 dBc/Hz at a 10 kHz offset frequency and an overlapping Hadamard deviation of 6.5×10−10 at an analysis time of 64 ms. The SAW resonator-based oscillator holds high potential in developing low-noise sensors and acousto-optic integrated circuits.
@article{arxiv.2409.03162,
title = {Low-phase-noise surface-acoustic-wave oscillator using an edge mode of a phononic band gap},
author = {Zichen Xi and Joseph G. Thomas and Jun Ji and Dongyao Wang and Zengyu Cen and Ivan I. Kravchenko and Bernadeta R. Srijanto and Yu Yao and Yizheng Zhu and Linbo Shao},
journal= {arXiv preprint arXiv:2409.03162},
year = {2025}
}