Patent ID: 8717651

Claim:
An optical device comprising: an optical device stage comprising: an optical input arranged to receive an optical input pulse at an input wavelength; an optical output arranged to output an optical output signal; an optical AND gate comprising a first input arranged to receive a part of said input optical pulse, a second input arranged to receive at least a part of a flip-flop optical output signal, and an output, and being arranged to generate an AND gate optical output pulse dependent on said flip-flop optical output signal; and an optical flip-flop comprising a first input arranged to receive a further part of said optical input pulse, a second input arranged to receive a said AND gate optical output pulse, and an output, and being arranged to generate said flip-flop optical output signal at a flip-flop output wavelength, and at least a part of said flip-flop optical output signal being provided to said optical output.