Electrical and optical on-chip interconnects in scaled microprocessors

The interconnect has become a primary bottleneck in integrated circuit design. As CMOS technology is scaled, it will become increasingly difficult for conventional copper interconnect to satisfy the design requirements of delay, power, bandwidth, and noise. On-chip optical interconnect is therefore being considered as a potential substitute for electrical interconnect. Based on predictions of optical device development, electrical and optical interconnects are compared for various design criteria. The critical dimensions beyond which optical interconnect becomes advantageous over electrical interconnect at the 22 nm technology node are approximately one tenth of the chip edge length.