Wafer-scale high-density Photonic Integrated Circuits

There is an increasing need for photonic integrated circuits (PICs) to advance technologies in sensing, datacoms and AI. These rely on complex optical circuitry containing passive and active compound semiconductor components, densely packed onto a wafer. The efficiency and functionality of the PIC depends strongly on the architecture of the building blocks and how they are connected. The structures here will be based on the indium phosphide (InP) material system; historically this has been widely used for generation, detection and amplification of light at the communication bandwidths. Versatile yet robust fabrication methods are required and in this project, fabrication of high-density PICs and complex epitaxial structures such as those used in quantum cascade lasers (QCLs) will be developed. As technology matures, the scale and complexity of manufacturing naturally increases. This presents processing challenges, particularly for InP, and this project will focus on the scaling and functionality of PICs which contain a high-density of micro/nano-structures, e.g. high aspect-ratio gratings and waveguides, studying the impact of dopants and composition on etching profiles. For certain components such as lasers or optical amplifiers, the application of thin-film coatings for high/low reflectivity (HR/AR) will be required and methods to apply these films as part of wafer-scale processing will be investigated.