Ultrafast Optical Logic with Semiconductor Nonlinear Directional Couplers

摘要

A resonant soliton scheme to implement ultrafast optical logic gates using semiconductor, nonlinear directional couplers (NLDC) has been investigated numerically. It has been demonstrated that the resonant soliton logic gates meet fundamental requirements for digital optical logic devices: logic level restoration, cascadability, and logical completeness. The operation of AND, OR, XOR, NOT, NOR, and NAND logic gates have been demonstrated in numerical simulations using 2 X 2 device configuration for a directional coupler. 3 X 3 NLDC design has been suggested to implement logically complete gates without necessity to cascade two or more couplers. Using 3 X 3 device configuration, an inventor (NOT gate) and a NOR gate have been implemented. The opening characteristics of the resonant soliton logic gates have been investigated numerically using 100 fs input pulses with 2 (pie) pulse area. It has been shown that the operating speed of all constructed gates is 2 Tbit/s, the operation is bit-rate flexible, the signal-to-noise ratio is generally higher than 4, and the latency is on picosecond timescale. Quantitative comparison between the operating characteristics of the resonant soliton logic gates and the corresponding parameters of NOLM gates (fiber optics) and also semiconductor electronic logic gates has been made. A conclusion has been drawn that the resonant soliton logic gates represent a novel and unique class of all-optical devices which are capable to operate at least 100 times faster than the most advanced electronic gates.