Patent ID: 8149488

Claim:
A method of operating an optical logic gate in order to perform a logic operation on optical input signals, the optical logic gate comprising a semiconductor optical amplifier having an output connected to a band pass optical filter, the method comprising: inputting first and second optical input signals having different wavelengths (λ A λ B ) to an input of the semiconductor optical amplifier, the first and second input optical signals having high and low states and each optical input signal configured to saturate the semiconductor optical amplifier when in the high state; inputting a probe signal into the semiconductor optical amplifier, the probe signal having a probe wavelength substantially equal to a four wave mixing product (λ FWM ) of the first and second wavelengths of the optical input signals; filtering the output of the semiconductor optical amplifier using the band-pass optical filter; and the band pass optical filter having a central wavelength substantially equal to the probe wavelength (λ FWM ).