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 solutio ns to overcoming the communication bandwidth bottleneck between VLSI chips. Large-scale demonstrators based on optical interconnects, when fully opera tional, can exhibit today the same aggregate bandwidth as that foreseen by the Roadmap for the year 2007. Massive parallelism, low input/output drivin g energy over large distances, and synchronous processing of hundreds of op tical 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 c omponents with VLSI chips, suitable types of optoelectronic device and the three main approaches to constructing optical data links: fibre-ribbons, pl anar waveguides and free-space optics.