Implementation of 1×2 decoder and XOR-XNOR logic functions on a PhC structure

Abstract

In this article, a photonic crystal based 1 × 2 decoder is proposed with dual output logic using T-shaped beam splitters and waveguides which can also be used for the concurrent implementation of XOR and XNOR logic functions. The type of interference at two T-shaped junctions is determined by the phase difference of the input light beams. Phase of the light defines the input logic whereas the light intensity discriminates the output. The proposed design has resulted with a high contrast ratio of 41.9 dB and 29.4 dB at a bit rate of 2.10 Tbps and 1.29 Tbps, at the output ports Y0 and Y1, respectively. Furthermore, the calculated fabrication tolerance of the proposed structure shows that the splitter rod's radius can be allowed to vary within ±5% from the optimal value. This results in a small change of 4.4% and 2.3% from the observed value of the contrast ratio at the ports Y0 and Y1, respectively, which is trivial.