Design, simulation and optimization of an ultracompact all-optical encoder based on 2D-PC

In this paper, a new design of an all-optical 4 × 2 encoder based on 2D photonic crystal (PC) structures with a very good CR has been presented. Simulations and optimizations were performed to improve the performance of the structure. To achieve the desired results, Nano-resonators (NRs) were used to reduce noise distribution and losses. The symmetrical structure caused the encoder to have the same performance in various conditions. Due to the use of NRs and the symmetrical structure, the size of the structure was about 136.4 µm². The results obtained from the structure simulation showed the contrast ratio (CR) of 14.88 dB, the response time of 2 ps, and the bit rate (BR) of 5 Tbps. The central wavelength of 1550 nm was used for the simulations. Power applied to the structure in each of the stages was equal to 1 mW/µm². Structural parameters such as the radius of dielectric rods, the value of lattice constant, and the size of NRs were optimized and the effects of input power intensity, wavelength, and operating frequency on the results obtained from the simulations were investigated. The results indicated the proper design of the structure that can be used in optical integrated circuits. In the present paper, the plane wave expansion (PWE) method was used to extract the photonic bandgap (PBG) and the finite-difference time-domain (FDTD) method was used to obtain the results of the output spectrum.