Photonic crystal based integrated system for half adder and half subtractor operations.

In this paper, the implementation of an integrated system of half adder and half subtractor based on 2D Si-air photonic crystal is proposed. The structure includes two input ports, one control port, and two output ports. When light is absent in the control port, the structure operates as a half adder and when light is present in the control port, it functions as a half subtractor. The operation of the structure is based on the phenomenon of constructive and destructive interference of light waves. The novelty of the proposed structure is that using a single control signal, both half adder and half subtractor operations can be realized. Since no nonlinear material has been used to design the structure, the power consumption of the structure is very low. Another advantage of the structure is that same materials have been used for all the rods which makes the fabrication process easier. The structure has been simulated by utilizing PWE and FDTD methods. Different performance parameters such as contrast ratio, rise time, delay time, fall time, response time, and bit rate for the designed structure have been obtained as 14.78 dB, 0.25 ps, 0.3 ps, 0.11 ps, 0.44 ps, and 2.27 Tb/s respectively. Due to its high contrast ratio, fast response time, high bit rate, and smaller dimension, the designed structure can be a promising candidate for realizing high speed optical integrated circuits. [ABSTRACT FROM AUTHOR]