III-V/Si Hybrid Laser Arrays Using Back End of the Line (BEOL) Integration
Creating arrays of efficient optical sources to enable dense integration of silicon photonic transceivers with silicon very large-scale integration circuits remains a challenge. We review manufacturing strategies and challenges for back-end-of-line integration of tunable, external-cavity lasers using edge-coupled and surface-normal-coupled integration approaches showing that such laser arrays can be manufactured with a fab-less model. We demonstrate, for the first time, hybrid laser arrays using both integration approaches highlighting performance and design differences. We also discuss challenges and opportunities for each method and present experimental techniques to reduce alignment tolerance and improve laser stability and mode control.