Design and Simulation of Micro-ring Resonator based Optical Comparator

Digital comparators are one of the basic combinational logics used in digital electronic circuits. These conventional devices consist of copper interconnects and use CMOS transistors as building blocks. CMOS technology has almost reached its limit with the transistor sizes being reduced to as low as 7 nanometers. Micro-ring resonators (MRR) have found its application in designing optical combinational and sequential circuits. In this paper, an all-optical magnitude comparator has been designed and simulated using two different wavelengths of light with same or different values of amplitude which are supplied to the dual micro-ring resonator. The intensity and position of outputs determine the results of comparison. Ring resonator designs occupy a small area of 1500 μm² and also have a high quality factor of 627 for a single ring resonator design whose effective refractive index is calculated to be 2.285. The FSR and FWHM values are 33.34 nm and 5.07 ns respectively. These devices can operate at high frequencies of 1.6 THz. Unlike conventional devices, the propagation delay is only 640 fs.