Portas lógicas de duas e três entradas numa fibra de cristal fotônico de três núcleos

Abstract

The propagation of 100 femto-second (fs) solitonic pulses in a photonic crystal fiber (PCF) can be simulated by solving the coupled mode non-linear equations with the 4th order Runge-Kutta method. In this work we aim to obtain a device capable of performing the three - input OR and AND logic operations. The device must be of small length and operate with low-intensity pulses modulated in PAM-ASK. For this we use a new methodology in which we give special focus to the dimensioning of the couplers’ length (by searching for logic gates in couplers whose lengths are smaller than the coupling length) and in the utilization of cores (using of all cores as guides in which signals can be processed). Like this, we numerically demonstrate the acquisition of two all-optical devices that perform the OR and AND logic operations on a solid core PCF with three symmetrical cores in planar array. For the first device, we obtained the passive three-input OR and AND all-optical logic gates, which operated with contrast rations higher than 0,3 dB (high performance), so they could be used to replace more complex optical circuits (in which the occurrence of Boolean expressions like the three-input OR and three-input AND are very common). This result eliminates the need for the concatenation of elementary logic gates, therefore saving space and eliminating problems regarding the cascading of logic gates. For the second device, we obtained the active two-input OR and AND all-optical logic gates, which operated with exceptionally high contrast ratios and could therefore be used in optical signals processing.