Ultra-fast all-optical polarization-encoded modified signed-digit addition using terahertz-optical-asymmetric-demultiplexer (TOAD) switches

In this paper, enhanced designs for ultra-fast all-optical circuits based on the terahertz-optical-asymmetric-demultiplexer (TOAD) adders are proposed. The high speed is achieved due to the use of the nonlinear optical materials and the nonbinary modified signed-digit (MSD) number representation. The proposed all-optical circuits use polarized light to present the trinary digits of the MSD numbers. It will be shown that the polarization-encoded MSD adder uses much less TOADs switches (37.5% less) and it is faster by 33.33% compared to the intensity-encoded ones.