Three-Dimensional Integrated Photonic-Phononic Circuit

The coherent optomechanical interaction between acoustic and optical waves known as stimulated Brillouin scattering (SBS) can enable ultra-high resolution signal processing and narrow linewidth lasers important for next-generation wireless communications, precision sensing, quantum information processing, and many more. But the proliferation of such a unique and powerful technology is currently impeded by fundamental challenges associated with circuit integration of Brillouin optomechanics in a versatile and mass producible material platform such as silicon nitride. The absence of acoustic guiding and the infinitesimal photo-elastic response of standard silicon nitride devices render conventional SBS in this material platform currently out of reach. An innovative approach that breaks with usual paradigms of actuating SBS solely through optical forces in two-dimensional waveguiding circuit is required to overcome these fundamental limitations. The TRIFFIC project aims to actuate and subsequently functionalize SBS in silicon nitride through three-dimensional (3D) integration of gigahertz acoustic wave sources and waveguides with low loss optical circuits. The two orders of magnitude SBS gain enhancement expected from this project will unlock Brillouin optomechanics in silicon nitride circuits for the first time. Using this novel 3D optomechanical platform, I aim to demonstrate a revolutionary concept of on-demand and programmable optomechanics that will transform the field of RF photonics by providing an advanced signal processor with comprehensive spectral control beyond what is currently possible. Further, I will demonstrate Hz-linewidth integrated SBS lasers in the red and blue visible wavelengths that can be integrated with future portable optical atomic clocks and trapped ion quantum computers. The ERC Consolidator will be instrumental for me to achieve these ambitious research objectives that will enable the optomechanics revolution in integrated optics.