Multiplier Architectures: Challenges and Opportunities with Plasmonic-based Logic

Emerging technologies such as plasmonics and photonics are promising alternatives to CMOS for high throughput applications, thanks to their waveguide's low power consumption and high speed of computation. Besides these qualities, these novel technologies also implement logic functionalities uncommon to traditional technologies that can be beneficial to existing CMOS architectures. In this work, we study how plasmonic-based devices can complement CMOS technology to achieve a more efficient implementation of multiplier architectures, which are the core of state-of-the-art data- and signal-processing circuits. A critical part of modern multipliers is the partial-product reduction step, used to reduce the partial product tree into a 2-input addition. In CMOS technology, this step is achieved by using compact and fast counters. On the other hand, the proposed plasmonic cells naturally implement counters of 3-, 9- and 27-inputs within a few logic levels at ultra-high speed. Thus, we present novel multiplier architectures, which take advantage of large plasmonic-based counters to reduce the number of cells and logic levels in the partial product reduction step of the multiplication. Our experimental results show that 3 levels and 30 counters are needed when 27-input cells are used. On the other side, 6 levels and 72 counters are employed with 9-input cells. Finally, we present various 16 x 16 multiplier implementations mixing 9- and 27input cells, focusing on the trade-off in the number of counters, levels, and area of each architecture.