Balancing electrical and optical interconnection resources at low levels

Free-space optical interconnections within a single chip can slow or halt the growth in the number of metal levels required as the gate count increases. Quantifying these benefits leads to the following interesting conclusions and questions. Free-space optical resources can be related to an equivalent number of metal levels. Optical interconnects can be used to augment metal resources in order to reduce wire-limited chip size. Increased regularity of the optical interconnect pattern leads to increased interconnection capacity. Under certain circumstances, microprocessor chip diameter can scale with no growth in the average or maximum metal wire length.