Foundry-Processed Optomechanical Photonic Integrated Circuits

Photonic integrated circuits (PICs) are a maturing technology with foundries enabling wafer-scale PIC fabrication. At the same time, optomechanics, in which micro-/nano-optical and -mechanical structures are coupled, is well-established with many basic research and practical applications. However, optomechanical devices have so far required highly-customized fabrication that limits their inclusion in foundry-processed PICs. To address this need, we design optomechanical PICs using standard low-loss process design kit (PDK) components. Our approach ensures access to the foundry’s low-loss PDK components and enables process compatibility. As a demonstration, we design a foundry-processed optomechanical Mach-Zehnder interferometer (MZI). Measurements demonstrate that a π-phase shift can be accumulated over an optomechanical interaction length of only 60 µm and tunable phase shifting can be achieved using gradient electric force actuation. We further demonstrate all-optical excitation and readout of mechanical resonances for sensing applications. Our PDK-focused optomechanics design approach enables the co-integration of optomechanics, photonics, and electronics in a single PIC.