All optical reversible design of Mach-Zehnder interferometer based Carry-Skip Adder

Nowadays, the design of optical circuits and devices is receiving wide attention among the researchers due to ultra-high speed and low-power consumption properties in the optical devices and interconnects. Chip level implementation of such optical circuits is under intense investigation by the research community. This work proposes an optical implementation of functionally reversible Carry-Skip Adder (CSA) circuit. Semiconductor optical amplifiers (SOA) based Mach-Zehnder interferometers (MZI) have been used to design the CSA circuit. Two separate designs of CSA are demonstrated. In the first design, a n-bit optical CSA is designed by considering 2-bit CSA module as a basic building block, whereas in the second design, multiple 4-bit CSA blocks are integrated to design the same n-bit optical CSA circuit. Comparative analysis with existing optical adder circuits shows that both the designs are cost and delay efficient compared to the existing designs.