Patent ID: 7463804

Claim:
An all-optical AND gate comprising: first and second optical input media for receiving respective first and second amplitude-modulated optical input signals, the first and second amplitude-modulated optical input signals having respective data with binary logic levels; a combining medium optically coupled to the first and second optical input media, the combining medium configured to receive and combine the first and second optical input signals to produce a combined signal; a nonlinear element configured to receive the combined signal, the nonlinear element having an optical resonator with a resonant frequency tuned relative to the frequency of at least one of the first and second optical input signals so that the nonlinear element outputs light as an optical output signal with a high logic level only if the combined signal results from both the first and second optical input signals having high logic levels, and the nonlinear element outputs substantially no light as the optical output signal with a low logic level if the combined signal results from either or both of the optical input signals having a low logic level, the optical output signal thus having a binary logic level that is amplitude-modulated; and an optical output medium optically coupled to receive and output the optical output signal from the nonlinear element, the first and second optical input media, combining medium, nonlinear element and optical output medium formed in a photonic crystal, the first and second optical input media, the combining medium, and the optical output medium defined by the absence of structures in the photonic crystal, the nonlinear element optically positioned between an output side of the combining medium and an input side of the optical output medium.