Editorial Editorial Introduction to JSTQE Special Issue on Photonic Electronic Co-Integration and Advanced Transfer Printing

Welcome to the IEEE Journal of Selected Topics in Quantum Electronics (JSTQE) Special Issue on Photonic Electronic Co-Integration and Advanced Transfer Printing . Over the past two decades, we have witnessed the establishment and adoption of integrated photonic platforms which allow the design and fabrication of chips that can contain a few dozen up to even hundreds of photonic components. These so-called photonic integrated circuits (PICs) are manufactured at wafer-scale, potentially allowing similar high-volume and low-cost fabrication that has been driving the electronics industry for over half a century. A first main platform is the Indium Phosphide process which allows manufacturing of PICs that contain passive devices (waveguides, optical filters etc.), active opto-electronic devices (detectors and modulators) and optical gain elements (optical amplifiers and lasers). The second process that has emerged is Silicon Photonics, which here refers to both the SOI (Silicon-on-insulator) and the SiN (Silicon Nitride) processes. The SOI-based platform allows for integration of both passives and active devices, however monolithic integration of optical gain elements remains a difficult challenge due to Silicon's indirect bandgap. SiN platforms originally only included passive functionality, although recently monolithic platforms that include both SOI and SiN waveguides have started to emerge. A few Silicon Photonic platforms that monolithically integrate both photonics and electronics have also been established by both academia and industry.