Semiconductor optical amplifiers (SOAs) are useful nonlinear components, which are the key elements for all-optical gates. This paper is devoted firstly to nonlinear elements based on SOAs. Secondly, a novel configuration using two cascaded SOAs will be presented. Besides the simplicity of this assembling, the gain nonlinearity is accentuated by the mutual gain modulation of the two SOAs which is an interesting feature to improve XGM applications. The reported results point essentially on static characteristics and applications. A spatial evolution of the XGM across the two SOAs cavities is simulated to evaluate and optimize the performances of this configuration. All-optical functions, such as a switch and a NOR gate, will be presented by using two SOAs of 500 μm and 750 μm lengths.
We investigate theoretically and experimentally the performances of two cascaded Semiconductor Optical Amplifiers (SOAs) in a counter-propagating topology. This configuration accentuates the gain non-linearity due to the mutual modulation of the two SOAs. Experimental results are obtained by using two SOAs of 500 μm and 750 μm lengths. By using this configuration, we present the performances of two all-optical functions. Firstly we demonstrate experimentally the all-optical switching operation for 2.5 GHz data pulses. Secondly we show the principle and the experimental results of all-optical logic NOR gate. For these two functions, an extinction ratio higher than 12 dB can be obtained for a wide range of input data wavelength between 1490 nm and 1560 nm.