Piezoelectrically driven Fano resonance in silicon photonics

Abstract

Piezoelectric optomechanical platforms provide a promising avenue for efficient signal transduction between microwave and optical domains. Lead zirconate titanate (PZT) thin film stands out as a compelling choice for building such a platform given its high piezoelectricity and optical transparency, enabling strong electro-optomechanical transduction. This work explores the application of such transduction to induce Fano resonance in a silicon photonics integrated circuit (PIC). Our methodology involves integrating a PZT thin film onto a silicon PIC and subsequently removing the SiO2 layer to suspend the silicon waveguide, allowing controlled mechanical vibrations. Fano resonances, characterized by their distinctive asymmetric line shape, were observed at frequencies up to 6.7 GHz with an extinction ratio of 21 dB. A high extinction ratio of 41 dB was achieved at the lower resonance frequency of 223 MHz. Our results demonstrate the potential of piezoelectric thin film integration for the generation of Fano resonances on passive photonic platforms such as Si, paving the way for highly sensitive, compact, and power-efficient devices relevant to a wide range of applications.