Initial Results of Prototyping a 3-D Integrated Intra-Chip Free-Space Optical Interconnect
A new optical interconnect system for intra-chip communications based on free-space optics is summarized in this paper. All-to-all direct communications is provided using dedicated lasers and photodetectors, hence avoiding packet switching while offering ultra-low latency and scalable bandwidth. A board-level prototype for technology demonstration is built using fabricated germanium photodetectors, micro-lenses, commercial Vertical-Cavity Surface-Emitting Lasers (VCSELs), and micro-mirrors. Measured from the prototype setup, transmission loss in an optical link of 10-mm distance is measured as 5 dB. Small-signal bandwidth of the link is 10 GHz.