Based on cross-gain modulation (XGM) in cascaded semiconductor optical amplifiers (SOAs), all-optical AND and NOR operations at 20Gb/s were both realized in the same configuration for the first time. By controlling the input signal power, the two logic gates can be achieved from different output channels. Single-port-couple SOAs with 1000μm active regions are exploited to improve the output performance. The dependence of the output characteristics on the input signal power and wavelength was also investigated.
A configuration of semiconductor fiber ring laser (SFRL) is used to achieve a tunable all-optical logic NOR gate at 20 Gb/s. Both gain and gain modulation is provided by a single semiconductor optical amplifier (SOA) in the ring cavity. In the theoretical simulations, sectional model is used for SOA and iterative condition is used for ring cavity to simulate the output from SFRL. All-optical NOR operation is successfully demonstrated experimentally at 20 Gb/s. There is a good agreement between theoretical simulations and experimental results. The extinction ratio higher than 14.9 dB is obtained as the output wavelength is tuned from 1530nm to 1560nm.
We analyze the all-optical wavelength converter (AOWC) based on a single-port-coupled (SPC) semiconductor optical amplifier (SOA). A comprehensive dynamic model is developed by considering longitudinal variations of carrier density, the residual rear-facet reflectivity of SOA and wide-band spontaneous noise emission (ASE). The numerical simulations for the novel wavelength conversion at 10Gbit/s are presented based on the model. The impact of the rear facet reflectivity on extinction ratio and conversion efficiency is analyzed. We find that when the reflectivity is in the range of 0.2 and 0.3, the extinction ratio over 10dB and the conversion efficiency over 0dB can be achieved. The pattern effect is also discussed to optimize the reflectivity. The wavelength conversion experiments employing two single-port-coupled SOAs with different reflectivity are demonstrated. The extinction ratio and conversion efficiency are measured. The experimental results are agreement with the simulation results.