OPTICAL DEVICES AND METHOD OF COUNTING OPTICAL PULSES

摘要

An optical device (10) comprises an optical device stage (12), which comprises an optical input (14), an optical AND gate (16), an optical flip-flop (18) and an optical output (26). The optical input (14) is arranged to receive an optical input pulse at an input wavelength. The optical AND gate (16) comprises a first input (16a) arranged to receive a part of said optical input pulse, a second input (16b) arranged to receive at least a part of a flip-flop optical output signal, and an output (16c). The optical AND gate (16) is arranged to generate an AND gate optical output pulse dependent on said flip-flop optical output signal (24). The optical flip-flop (18) comprises a first input (18a) arranged to receive a further part of said optical input pulse, a second input (18b) arranged to receive a said AND gate optical output pulse, and an output (18c). The optical flip-flop (18) is arranged to generate said flip-flop output signal at a flip-flop output wavelength. A least a part of the flip-flop output signal (24) is provided to said output (26).