Abstract
Limits on energy consumption in digital optical integrated circuits (ICs) using conventional and plasmon waveguide interconnects are presented. The maximum allowable on-chip power density imposes a lower limit on the spacing between devices and together with clock skew imposes an upper limit on the clock frequency. Optical ICs with low-loss plasmon waveguide interconnects may become viable if plasmon waveguide losses in the range 0.1-0.01 dB/m can be achieved.