Micromachined Free-Space Integrated Optics for Computing Applications

Free-space optical interconnects have been shown to be very promising for providing input/output capacity in excess of a terabit per second for next generation VLSI chips [1] and 3D chip stacks [2]. In the past few years, significantly progress has been made in ultra-low threshold vertical cavity surface-emitting laser (VCSEL) arrays [3], which makes it feasible to integrate large, dense 2D arrays of VCSELs for free-space optical interconnects. However, packaging of such free-space optical systems remains a formidable task. Bulk optical elements often limit the sizes of such systems. Assembly and alignment of the optical systems are tedious and expensive. Furthermore, such free-space optical systems are often constructed on optical benches in laboratories, and might not be rugged enough for typical environment for computing systems.