All-optical reconfigurable non-inverted logic gates with a single semiconductor optical amplifier

All-optical reconfigurable non-inverted logic gates with a single semiconductor optical amplifier (SOA) is proposed. Compared with the probe light of continuous light, the clock (Clk) pulse sequences light is regarded as the probe light so that the output of logic gates is a non-inverted code which is suitable to the further combination of different logic gates. The scheme is based on a single SOA with four-wave mixing and cross-gain modulation. Multiple functional logic operations are implemented and switched by adjusting the center wavelength of tunable optical band-pass filter without altering the experimental device. In the experiment, all-optical multiple logic gates with 10 Gb/s return-to-zero of NOT, NOR, XNOR, AND, A¯•B and A•B¯ are realized. Meanwhile, because Clk probe light is a small signal, a saturable absorber (SA) is configured to improve the extinction ratio (ER) and optical signal to noise ratio (OSNR). For logic gates NOT, NOR and XNOR with Clk probe light, ER and OSNR are only deteriorated by 1 dB with the SA. For logic gate AND with Clk probe light, ER is improved by about 2 dB based on four-wave mixing and OSNR keep the original values with the SA respectively. For logic gates A¯•B and A•B¯ without Clk probe light, ER and OSNR are both only deteriorated by 0.5 dB. It has the potential to obtain more complex combinational logic gates.