Logic gates based on optical transistors

In this paper a simple and novel scheme to develop optical logic gates for fast switching. This can be obtained by sending two laser beams coaxially through nonlinear media with saturating nonlinearity. The nonlinearity in the optical properties on the medium is assumed to be cubic quintic nonlinearity. Semianalytical solutions of the wave equations for the fields of incident laser beams have been obtained by using a variational formalism. Emphasis are put on dynamical variations of beam widths of the laser beams with distance of propagation through the medium. It has been found that the weak beam modulates the intensity variations of the strong beam that giving rise to the possibility of an optical transistor. Combinations of these optical transistors can further be used to obtain logic gates.