We have demonstrated experimentally that optical Not-OR (NOR) and Not-AND (NAND)
operations can be done with a single setup. The setup is capable of processing parallel
inputs. Two barium titanate (BaTiO3) crystals are used in the setup and photorefractive
effects are employed. Instead of using the interference between the two input signals to
be processed or the so called local incoherent erasing, the setup works on the
phenomenon of self-pumped phase conjugation and the suppression of it by the input
signals in ordinarily polarized state. In this way, the two input
channels can be mutually incoherent.