Fig. 1: Hybrid nanophotonic high-overtone bulk acoustic resonator (HBAR) platform.
From: Hybrid integrated photonics using bulk acoustic resonators
a 3D schematic illustrating excitation of bulk acoustic waves via a macroscopic piezoelectric actuator, which transmit vertically into the stack and form acoustic standing waves inside the acoustic Fabry–Pérot cavity. The resonance-enhanced mechanical stress changes the waveguide’s refractive index via the stress-optical effect and thereby modulates the output optical intensity. b Cross-section of the device along the black dashed line in c, with critical dimensions labeled. The AlN piezoelectric actuator is placed directly on top of the Si3N4 microring resonator which is embedded in 5.4 μm of SiO2 cladding. c Optical microscope image of the fabricated device.
