Quantitative Comparison of Optical and Electrical H, X, and Y clock Distribution Networks

In this paper, optical clocking systems are compared to electrical clocking systems. Three symmetrical optical clock distribution patterns, namely, H, X, and Y, are considered. The important factors for the optical distribution network are compared for different detector capacitances and clock tree shapes. The results show that the shape of clock distribution network does not have considerable impact on the delay of the optical system. The results also show that having high detector capacitances in the H-tree clock distribution networks, the total power consumption can exceed the power consumption of the electrical clock distribution networks. However the H-tree clock distribution network can reach 30% of the power saving at lower detector capacitances, which is the best power saving factor compare with X and Y-tree clock distributions.