Simple and reconfigurable all-optical logic gate

A photonics-based digital signal processing structure that has the ability to realise all the six basic logical operations, namely XOR, OR, AND, XNOR, NOR and NAND, is presented. It is based on applying the two digital inputs into a dual-polarisation modulator and adjusting the angle of a waveplate connected to the modulator output to realise different logical operations. The proposed dual-polarisation modulator based optical logic gate has a simple and compact structure and robust performance. Switching between different logical operations can be realised in high speed by adjusting only one system parameter, with no change in the system physical configuration. The proposed dual-polarisation modulator based optical logic gate is theoretically analysed. Using the system parameter setting obtained from the theoretical analysis, the six basic logical operations are experimentally demonstrated. To our knowledge, this is the first report of an optical logic gate that is capable of switching between all the six basic logical operations by adjusting only one system parameter.