Designs of all-optical buffer and OR gate using SOA-MZI

In the paper a novel scheme for an all-optical buffer and OR logic gates based on Mach-Zehnder interferometer structure is discussed. The operations of the scheme with 10 Gb/s return to zero pseudorandom bit streams simulated correctly with extinction ratio 19.21 and 17.61 dB where Q-factor 25.94 and 11.22 for buffer and OR gate respectively. With the help of numerical analyses, it can be seen that the extinction ratio of the OR operation is degraded and the output pattern effect is decreased by 0.9 dB compared to optical buffer schemes under the same condition. Furthermore, the carrier recovery time of a semiconductor optical amplifier is no longer a crucial parameter to restrict the operation speed of this scheme. The scheme is also potentially capable of multi input OR operation at higher speed.