Interference based all-optical 4 × 2 encoder

Abstract

In this article, we propose the design of all-optical photonic crystal based 4 × 2 encoder by interconnecting cross-shaped waveguide dependent OR gate. Initially the design and operation of photonic crystal based OR gate using cross-shaped waveguide is discussed with an additional reference input. The phase of all the input light signals are maintained at zero in order to have constructive interference to perform OR function. Later, OR gates are interconnected to realize encoder in such a way that the light path from the input ports to cross-shaped waveguide junctions be same. The structure is numerically simulated using Finite Difference Time Domain (FDTD) method and observed that the contrast ratio is 7.98 dB. Also, the size of the proposed structure is quite smaller by 84.7% and 22.07% than self-collimation and resonance based designs existing in the literature so far. With the fair results obtained, it can be concluded that the proposed encoder is suitable as a basic component in future Photonic Integrated Circuits.