Patent ID: 7995877

Claim:
An optical NAND gate which receives a pair of digital optical inputs each with a logic state and generates therefrom a digital optical output which is a NAND representation of the logic states of the pair of digital optical inputs, the optical NAND gate comprising: a substrate; an optical AND gate formed on the substrate and comprising a first electroabsorption modulator and a first waveguide photodetector, with the first electroabsorption modulator receiving a first digital optical input of the pair of digital optical inputs, and with the first waveguide photodetector receiving a second digital optical input of the pair of digital optical inputs and generating therefrom a photocurrent signal, and with the photocurrent signal being connected to modulate an absorption of the first electroabsorption modulator through which the first digital optical input is transmitted and thereby convert the pair of digital optical inputs into a logical AND function output of the first electroabsorption modulator; and an optical NOT gate formed on the substrate and comprising a second electroabsorption modulator and a second waveguide photodetector, with the with the second waveguide photodetector receiving the logical AND function output from the first electroabsorption modulator and generating therefrom another photocurrent signal which is electrically connected to modulate the absorption of the second electroabsorption modulator which receives an input of continuous light, thereby converting the continuous light input into the digital optical output of the optical NAND gate.