The document introduces the operation of a photonic full adder. It discusses using different wavelengths of light modulated with binary data and polarized in different ways to represent logic values. The full adder circuit uses these photonic logic gates such as AND, OR, and wavelength converters. It provides a detailed explanation of how the circuit works at each logic gate using the photonic representation and constructive/destructive interference of the wavelengths. The document also notes some optimizations that could be made to the circuit design to reduce components like wavelength converters.