Design and simulation of a compact all-optical 2-to-1 digital multiplexer based on photonic crystal resonant cavity

摘要

Abstract In this paper, a new structure based on the two-dimensional photonic crystal for an all-optical 2-to-1 digital multiplexer has been proposed. The structure includes a 15 × 15 array of chalcogenide rods with a spatial period of 596 nm. Two resonant cavities couple the incoming optical waves in response to the amount of the optical intensity. The effective refractive index of the cavity changes corresponding to the optical intensity. By adjusting the radii of nonlinear rods, the coupling efficiency is maximized so the optical waves transmit to the output port. Accordingly, the multiplexing operation in a small area of the photonic crystal is obtained. The finite difference time domain method is used to calculate the components of the electric and magnetic fields throughout the structure. The area of the structure is just 80 µm2, smaller than the previous works. Also, the rise time of 185 fs demonstrates the fast response of the proposed multiplexer. The contrast ratio of the structure is equal to 18.9 dB and makes a high gap between logic 0 and logic 1. The small area, fast response, and high contrast ratio of the designed structure promise the proposed digital multiplexer for use in optical processing.