All-optical wavelength coded logic gates

Abstract

All-optical logic gates in which binary words are encoded using wavelength. A method and apparatus for processing information in this wavelength encoded format is provided. The processing may occur entirely in the optical domain. This approach is modular and enables construction of logic gates using custom wave guide chips that can be mass-produced in a manner similar to that of conventional electronic digital chips. Specific gates, such as AND, OR, EXOR, or NAND, may be 'programmed' into a given chip during its fabrication to encode the desired truth table. The output states of the chip are determined by ultrafast mixing of binary encoded wavelengths in a semiconductor optical amplifier. The result is a new wavelength having a relationship to the input wavelengths determined entirely by the desired truth table. The possible clock-rates for these gates can be exceedingly high, such as several hundred Gigabits/second. The product of integer word length 'N' and gate clock speed can exceed several Terabits/second and may be as high as the overall optical bandwidth of the system. Complicated multi-input functions may be constructed using this approach and dynamically programmable functions may be built in which either electrical or optical signals reconfigure a set of gates by reprogramming the inverter operations in the chips.