AbstractHow can design engineers use epitaxial regrowth to enhance semiconductor laser performance and unlock new markets? First, we need to take a closer look at the relatively mature, epitaxial regrowth process for indium phosphide (InP) lasers, commonly used in 5G, datacomms, telecoms and co‐located optics applications. Then we can consider gallium arsenide (GaAs), a less mature material system, which suits a multitude of emerging industrial, biomedical imaging, datacomms, and sensing laser applications.