All-optical Logic Gates Based On Semiconductor Optical Amplifiers

In future high-speed optical networks, it is crucial to develop all-optical signal processing to avoid the limits of electronic bottlenecks. The optical logic gates, as important components of optical signal processing, have received much attention in recent years. Semiconductor optical amplifiers (SOAs) have many advantages such as small size, wide bandwidth and low response time, which make them a strong candidate to realize all-optical logic gates. Supported by the state Key Development Program for Basic Research of China (Grant No. 2000036605), the National High Technology Development Program of China (Grant No. 2002AA312160) and the National Natural Science Foundation of China (Grant No. 60407001), theoretical and experimental researches on all-optical logic gates based on SOA are presented in this paper. The main contents are listed as follows:(1) The research background, applications and achievements of all-optical logic gates are clarified. Two novel schemes for all-optical logic gates using XGM in SOA are proposed for the first time.(2) Based on the carrier density rate equation, optical power propagation equation and sectional model of SOA, the static and dynamic characteristics of SOA are theoretically simulated.(3) A novel scheme for all-optical NOR gate based on SOA fiber ring laser is proposed. The principle of operation and theoretical model of SOA fiber ring laser are presented. Theoretical results are simulated using the model. Experimental results for all-optical NOR gate at 10Gb/s, 20Gb/s and 40Gb/s are obtained. Some key factors in output performance are discussed.(4) A novel scheme for all-optical AND and NOR gate based on cascaded single-port-coupled SOAs are proposed. The principle of operation and theoretical model of cascaded single-port-coupled SOAs are presented. Theoretical results for logic AND and NOR operation are simulated and analyzed respectively. Experimental results up to 20Gb/s are obtained. Some key factors in output performance are discussed. There is a good agreement between theoretical and experimental results.