Gallium phosphide-on-insulator integrated photonic structures fabricated using micro-transfer printing

Gallium phosphide-on-insulator emerged recently as a promising platform for integrated nonlinear photonics due to its intrinsic material properties. However, current integration solutions, using direct die-to-wafer bonding, do not support spatially localized integration with CMOS circuits which induce a large and expensive footprint material need. Here we demonstrate the transfer of gallium phosphide layers to an oxidized silicon wafer using micro-transfer printing as a new approach for versatile future (hybrid) integration. Using this novel approach, we demonstrate as a proof of concept the fabrication of gallium phosphide-on-insulator ring resonators with Q-factors as high as 35,000.