​Professor Ooi's research is primarily concerned with the study of semiconductor lasers and photonic integrated circuits. Specifically, he has contributed significantly to the development of practical technologies for semiconductor photonics integrated circuits, and the development of novel broadband semiconductor lasers, multiple-wavelength lasers and superluminescent diodes. Most recently, he focuses his research on the areas of GaN-based nanostructures and lasers for applications such as solid-state lighting and visible light communications.