Optically interconnected electronic chips: a tutorial and review of the technology

Optoelectronic interconnects between VLSI chips have been identified by the Semiconductor Industry Association (SIA) Roadmap as one of the few solutions to overcoming the communication bandwidth bottleneck between VLSI chips. Large-scale demonstrators based on optical interconnects, when fully operational, can exhibit today the same aggregate bandwidth as that foreseen by the Roadmap for the year 2007. Massive parallelism, low input/output driving energy over large distances, and synchronous processing of hundreds of optical information input channels mean that these prototypes can potentially provide on/off communication rates in the tera-pin-Hz region (i.e. a total capacity of one terabit/s). After discussing the limitations of electrical interconnects this paper reviews the means of integrating optoelectronic components with VLSI chips, suitable types of optoelectronic device and the three main approaches to constructing optical data links: fibre-ribbons, planar waveguides and free-space optics.