Caption: Schematic diagram for signal processing via optically-driven acoustic wave interference.
Acoustic waves induced by pump light (blue line) interfere with the change of pump light phase on silicon waveguides. The scattering of the probe light (green line) can be controlled by the acoustic wave interference.
Active Information Manipulation via Optically Driven Acoustic-Wave Interference
Implementing on-chip information processing systems through photonic–phononic interactions has attracted considerable interest owing to its potential for storing, sensing, and signal processing, but the generation and extinction of acoustic waves are determined by the existence of pump power and the phonon lifetime. Here, we demonstrate the acoustic-wave interference and active information manipulation by optically driven acoustic waves in a silicon photonic–phononic controller-emitter-receiver system. The filtered and transmitted information to the receiver has a narrow bandwidth of 6.2 MHz and can be amplified or canceled with a contrast greater than 40 dB by adjusting the relative microwave phase between the emitter and controller. The pulse-train signals can be transmitted, amplified, and canceled with a 3 dB cutoff frequency of 3.1 MHz. The proposed technique provides a potential solution for highly selective on-chip filtering, phase shifters, and information manipulation, offering new functions to optomechanical signal processing and silicon photonics.