Incoherent all-optical NAND-, NOR-, and XOR-gate using photorefractive fanning effect

An all-optical computing device is proposed to perform incoherent digital o perations, including the NAND, NOR, and XOR gates. Instead of using interfe rometer-based methods, making use of self-generating noise gratings and the erasure of them by another beam in two photorefractive self-pumped phase c onjugators (SPPC), the device is able to process mutually incoherent as wel l as mutually coherent inputs. Changing the orientations of two polarizers and a photorefractive crystal, we are able to perform incoherent parallel N AND, NOR, and XOR operations with this proposed setup.